Gas and power company for California - FINAL …...FINAL REMOVAL ACTION WORKPLAN Former...

FINAL REMOVAL ACTION WORKPLAN

Former Watsonville-1 Manufactured Gas Plant

618 Main Street Watsonville, California

prepared for 3401 Crow Canyon Road

San Ramon, California 94583

prepared by

13900 Alton Parkway, Suite 122 Irvine, California 92618

October 27, 2011

Final Removal Action Workplan Former Watsonville-1 MGP Site

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TABLE OF CONTENTS TABLE OF CONTENTS ........................................................................................................................................... ii

LIST OF TABLES ......................................................................................................................................................vi

LIST OF FIGURES .................................................................................................................................................. vii

LIST OF APPENDICES .......................................................................................................................................... vii

LIST OF ACRONYMS ........................................................................................................................................... viii

ACKNOWLEDGEMENT AND SIGNATURE PAGE ...........................................................................................xi

EXECUTIVE SUMMARY ...................................................................................................................................... xii

1.0 INTRODUCTION ................................................................................................................................................. 1

1.1 General Information ........................................................................................................................................ 1

1.2 Purpose of the Removal Action Workplan ...................................................................................................... 1

1.3 RAW Organization .......................................................................................................................................... 1

2.0 BACKGROUND .................................................................................................................................................... 3

2.1 Property Location ............................................................................................................................................ 3

2.2 Property Description ....................................................................................................................................... 3

2.3 Property History .............................................................................................................................................. 3

2.4 Historic Evaluation .......................................................................................................................................... 4

2.5 Environmental Setting ..................................................................................................................................... 5

2.5.1 Geologic Conditions .............................................................................................................................. 5 2.5.1.1 Areal Geology ................................................................................................................................................... 5 2.5.1.2 Property Geology .............................................................................................................................................. 6

2.5.2 Hydrologic Conditions ........................................................................................................................... 6 2.5.2.1 Surface Water Hydrology .................................................................................................................................. 6 2.5.2.2 Areal Groundwater Hydrology .......................................................................................................................... 6 2.5.2.3 Property Groundwater Hydrology ..................................................................................................................... 7

2.6 Previous and Ongoing Environmental Studies ................................................................................................ 8

2.6.1 Preliminary Assessment by PG&E, 1986 .............................................................................................. 8 2.6.2 Preliminary Endangerment Assessment by CH2M Hill, 1991 ............................................................... 8 2.6.3 Community Profile by IT Corporation, 2000 and Craig Communications, 2009 .................................. 9 2.6.4 Site Investigation by IT Corporation, 2001 ........................................................................................... 9 2.6.5 Human Health Risk Assessment by IT Corporation, 2002 ................................................................... 10 2.6.6 Conceptual Remedy for the Watsonville-1 MGP Site by Shaw, 2003 .................................................. 10 2.6.7 Supplemental Site Investigation by ENV America, 2004 ..................................................................... 10 2.6.8 Additional Subsurface Investigation by TPG, 2008 ............................................................................. 11 2.6.9 Soil Gas Probe and Groundwater Monitoring Well Installation by TPG, 2009 .................................. 12 2.6.10 Soil Gas Monitoring ........................................................................................................................ 12 2.6.11 Groundwater Monitoring ................................................................................................................ 13


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2.6.12 Screening-Level Risk Evaluation by Iris Environmental, 2010 ....................................................... 13

2.7 Deed Restriction ............................................................................................................................................ 14

3.0 NATURE AND EXTENT OF IMPACT ............................................................................................................ 15

3.1 Introduction ................................................................................................................................................... 15

3.2 Soil ................................................................................................................................................................ 15

3.3 Soil Gas ......................................................................................................................................................... 19

3.4 Groundwater .................................................................................................................................................. 20

4.0 REMOVAL ACTION GOALS........................................................................................................................... 21

4.1 Overview ....................................................................................................................................................... 21

4.2 Soil ................................................................................................................................................................ 21

4.3 Soil Gas ......................................................................................................................................................... 21

4.4 Groundwater .................................................................................................................................................. 22

4.5 Applicable or Relevant and Appropriate Requirements ................................................................................ 22

4.6 Applicability of ARARs to the Property ....................................................................................................... 22

5.0 REMEDIAL ALTERNATIVES ......................................................................................................................... 24

5.1 Contaminants of Concern and Media of Interest ........................................................................................... 24

5.2 General Response Actions ............................................................................................................................. 24

5.2.1 General Response Actions for Soil ...................................................................................................... 24 5.2.2 General Response Actions for Soil Gas ............................................................................................... 25 5.2.3 General Response Actions for Groundwater ....................................................................................... 25

5.3 Identification and Preliminary Screening of Technologies and Process Options .......................................... 26

5.3.1 Screening of Technologies and Process Options for Soil .................................................................... 26 5.3.2 Screening of Technologies and Process Options for Soil Gas ............................................................. 28 5.3.3 Screening of Technologies and Process Options for Groundwater ..................................................... 29

5.4 Development of Alternatives ......................................................................................................................... 31

5.4.1 Remedial Alternatives for Soil ............................................................................................................. 31 5.4.2 Remedial Alternatives for Soil Gas ...................................................................................................... 32 5.4.3 Remedial Alternatives for Groundwater .............................................................................................. 33

5.5 Remedial Alternative Evaluation Criteria ..................................................................................................... 34

5.6 Description and Evaluation of Alternatives ................................................................................................... 35

5.6.1 Alternatives for Soil ............................................................................................................................. 36 5.6.1.1 Soil Alternative No. 1 – No Action ................................................................................................................. 36 5.6.1.2 Soil Alternative No. 2 – Capping with Institutional Control and Focused Excavation with Offsite Disposal . 36 5.6.1.3 Soil Alternative No. 3 - Excavation of Impacted Soil and Offsite Treatment ................................................. 38 5.6.1.4 Soil Alternative No. 4 - Excavation of Impacted Soil and Offsite Disposal .................................................... 41

5.6.2 Alternatives for Soil Gas ...................................................................................................................... 41 5.6.2.1 Soil Gas Alternative No. 1 – No Action .......................................................................................................... 41


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5.6.2.2 Soil Gas Alternative No. 2 – Soil Gas Monitoring with Institutional Control ................................................. 42 5.6.2.3 Soil Gas Alternative No. 3 – Soil Vapor Extraction and Vapor Treatment, Soil Gas Monitoring and Institutional Control ........................................................................................................................................................ 43

5.6.3 Alternatives for Groundwater .............................................................................................................. 45 5.6.3.1 Groundwater Alternative No. 1 – No Action................................................................................................... 45 5.6.3.2 Groundwater Alternative No. 2 – Monitored Natural Attenuation .................................................................. 45 5.6.3.3 Groundwater Alternative No. 3 – In situ Bioremediation ................................................................................ 46

5.7 Final Evaluation of Alternatives .................................................................................................................... 46

5.7.1 Comparison of Final Soil Alternatives................................................................................................. 47 5.7.2 Selection of the Final Soil Alternative ................................................................................................. 48 5.7.3 Comparison of Final Soil Gas Alternatives ......................................................................................... 49 5.7.4 Selection of the Final Soil Gas Alternative .......................................................................................... 50 5.7.5 Comparison of Final Groundwater Alternatives ................................................................................. 50 5.7.6 Selection of Final Groundwater Alternative ........................................................................................ 51

6.0 REMOVAL ACTION IMPLEMENTATION .................................................................................................. 53

6.1 Summary of Selected Remedial Approach .................................................................................................... 53

6.2 Quality Assurance/Quality Control (QA/QC) Plan ....................................................................................... 53

6.3 Soil Remediation Overview .......................................................................................................................... 53

6.3.1 Demolition ........................................................................................................................................... 53 6.3.2 Soil Removal ........................................................................................................................................ 54 6.3.3 Pavement Improvement ........................................................................................................................ 54

6.4 Property Security and Access ........................................................................................................................ 55

6.5 Traffic Control............................................................................................................................................... 55

6.6 Permit Requirements ..................................................................................................................................... 55

6.7 Agency Notification ...................................................................................................................................... 55

6.8 Soil Remediation ........................................................................................................................................... 56

6.8.1 Preliminary Activities .......................................................................................................................... 56 6.8.2 Soil Removal Activities ........................................................................................................................ 57

6.8.2.1 Equipment ....................................................................................................................................................... 57 6.8.2.2 Excavation Procedures .................................................................................................................................... 58 6.8.2.3 Backfill and Compaction ................................................................................................................................. 58

6.9 Restoration .................................................................................................................................................... 58

6.10 Waste Handling ........................................................................................................................................ 58

6.10.1 Types of Wastes ............................................................................................................................... 58 6.10.2 Transportation Plan ........................................................................................................................ 59

6.11 Spill Response Plan .................................................................................................................................. 60

6.12 Environmental Control ............................................................................................................................. 61

6.12.1 Noise ............................................................................................................................................... 61 6.12.2 Dust ................................................................................................................................................. 61


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6.12.3 Odor ................................................................................................................................................ 63 6.12.4 Decontamination ............................................................................................................................. 64

6.13 Stormwater Management .......................................................................................................................... 64

6.14 Health and Safety ..................................................................................................................................... 65

7.0 SAMPLING PLAN .............................................................................................................................................. 67

7.1 Objective ....................................................................................................................................................... 67

7.2 Soil Sampling ................................................................................................................................................ 67

7.2.1 Number and Location of Soil Samples ................................................................................................. 67 7.2.2 Soil Sampling Methodology ................................................................................................................. 67

7.3 Soil Gas Sampling ......................................................................................................................................... 68

7.4 Groundwater Sampling.................................................................................................................................. 69

8.0 CEQA COMPLIANCE ....................................................................................................................................... 70

9.0 PUBLIC PARTICIPATION ............................................................................................................................... 71

10.0 REMEDIATION SCHEDULE ......................................................................................................................... 72

11.0 PROPERTY CERTIFICATION ...................................................................................................................... 73

12.0 ADMINISTRATIVE RECORD LIST ............................................................................................................. 74

13.0 REFERENCES CITED ..................................................................................................................................... 79


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LIST OF TABLES

Table No.

Title

Table 2-1A Summary of PAH Concentrations in Soil Samples Table 2-1B Summary of Metals Concentrations in Soil Samples Table 2-1C Summary of TPH and TRPH Concentrations in Soil Samples Table 2-1D Summary of BTEX and MTBE Concentrations in Soil Samples Table 2-1E Summary of Ammonia, Cyanide, Sulfide, and Total Phenols Concentrations in Soil Samples Table 2-1F Summary of Physical Testing Results for Soil Samples Table 2-2A Summary of PAH Concentrations in Background Soil Samples Table 2-2B Summary of TPH and TRPH Concentrations in Background Soil Samples Table 2-2C Summary of Metals Concentrations in Background Soil Samples Table 2-2D Summary of Ammonia, Cyanide, and Sulfide Concentrations in

Background Soil Samples Table 2-3A Summary of PAH Concentrations in Groundwater Samples Table 2-3B Summary of VOC, TPH, Metal and Other Constituent Concentrations in

Groundwater Samples Table 2-4 Summary of TPHg and Detected VOC Concentrations in Soil Gas

Samples Table 4-1 Potentially Applicable or Relevant and Appropriate Requirements List Table 5-1A Summary of Technology Types and Process Options Screening for Soil Table 5-1B Summary of Technology Types and Process Options Screening for Soil

Gas Table 5-1C Summary of Technology Types and Process Options Screening for

Groundwater Table 5-2A Soil General Response Actions and Technology Types/Process Options

Retained for Further Evaluation Table 5-2B Soil Gas General Response Actions and Technology Types/Process

Options Retained for Further Evaluation Table 5-2C Groundwater General Response Actions and Technology Types/Process

Options Retained for Further Evaluation Table 5-3A Preliminary Remedial Cost Estimates for Soil Alternatives Table 5-3B Preliminary Remedial Cost Estimates for Soil Gas Alternatives Table 5-3C Preliminary Remedial Cost Estimates for Groundwater Alternatives


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Table 5-4A Screening of Remedial Alternatives for Soil Table 5-4B Screening of Remedial Alternatives for Soil Gas Table 5-4C Screening of Remedial Alternatives for Groundwater

LIST OF FIGURES

Figure No.

Title

Figure 1-1 Property Location Map Figure 1-2 Property Plan Figure 2-1 Parcel Map Figure 2-2 Sampling Location Map Figure 2-3 Background Soil Sample Location Map Figure 3-1 Benzo(a)Pyrene Equivalent Concentration Map Figure 6-1 Excavation Plan Figure 7-1 Soil Sampling Plan

LIST OF APPENDICES

Appendix

Contents

Appendix A Draft Screening-Level Vapor Intrusion and Soil Data Health Risk Evaluation Report

Appendix B Deed Restriction Appendix C Quality Assurance/Quality Control Plan Appendix D Responsiveness Summary Appendix E Notice of Exemption


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LIST OF ACRONYMS

afy acre-feet per year APN Assessor Parcel Number ARAR Applicable or Relevant and Appropriate Requirement ASGI Active Soil Gas Investigations ASTM American Society for Testing and Materials, now ASTM International B(a)P benzo(a)pyrene BTEX benzene, toluene, ethylbenzene and total xylenes bgs below ground surface Cal/EPA California Environmental Protection Agency Cal/OSHA California Occupational Safety and Health Administration CAM California Assessment Manual CCG&E Coast Counties Gas and Electric Company CCR California Code of Regulations CEQA California Environmental Quality Act CERCLA Comprehensive Environmental Response, Compensation and Liability Act CFR Code of Federal Regulations CHP California Highway Patrol CHSC California Health and Safety Code CMP corrugated metal piping COC chemical of concern COPC chemical of potential concern CPAH carcinogenic polycyclic aromatic hydrocarbon dBA decibels DOSH California Division of Occupational Safety and Health DOT Department of Transportation DQO data quality objective DTSC Department of Toxic Substances Control EE/CA Engineering Evaluation and Cost Analysis ENTRIX ENTRIX, Inc. ENV America ENV America Incorporated ESCP Emergency Spill Contingency Plan FID flame ionization detector FIFRA Federal Insecticide, Fungicide, and Rodenticide Act HI hazard index HHRA Human Health Risk Assessment HSP Health and Safety Plan IT IT Corporation MBUAPCD Monterey Bay Unified Air Pollution Control District


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LIST OF ACRONYMS - continued

MDL method detection limit mg/kg milligrams per kilogram mg/L milligrams per liter mg/m3 milligrams per cubic meter MGP manufactured gas plant mL/min milliliter per minute MNA monitored natural attenuation MS/MSD matrix spike/matrix spike duplicate msl mean sea level MTBE methyl tertiary-butyl ether NCP National Contingency Plan NEPA National Environmental Policy Act NHPA National Historic Protection Act NIST National Institute for Standards and Technology NRHP National Register of Historic Places O&M operation and maintenance ORC Oxygen Release Compound OVA organic vapor analyzer PAH polycyclic aromatic hydrocarbon PCB polychlorinated biphenyl PEA Preliminary Endangerment Assessment PEL permissible exposure limit PG&E Pacific Gas and Electric Company PID Photoionization detector PPE personal protective equipment ppm parts per million PRG Preliminary Remediation Goal Property Portion of former Watsonville-1 MGP located at 618 Main Street PVWMA Pajaro Valley Water Management Agency QA/QC quality assurance/quality control RAG removal action goal RAW Removal Action Workplan RCRA Resource Conservation and Recovery Act RMC Raines, Melton & Carella, Inc. RPD relative percent difference SDWA Safe Drinking Water Act Shaw Shaw Environmental, Inc.


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LIST OF ACRONYMS – continued

SI Site Investigation Site Watsonville-1 Former Manufactured Gas Plant Smith Smith Technology Corporation SSI Supplemental Site Investigation TDS total dissolved solid TPG Terra Pacific Group Incorporated TPH total petroleum hydrocarbons TPHd total petroleum hydrocarbons quantified as diesel TPH-e extractable total petroleum hydrocarbons TPHg total petroleum hydrocarbons quantified as gasoline TPHmo total petroleum hydrocarbons quantified as motor oil TPH-p purgeable total petroleum hydrocarbons TRPH total recoverable petroleum hydrocarbons TSCA Toxic Substances Control Act USCS Unified Soil Classification System USEPA United States Environmental Protection Agency USGS United States Geological Survey VOC volatile organic compound µg/L micrograms per liter µg/kg micrograms per kilogram µg/m3 micrograms per cubic meter ºC degrees Centigrade ºF degrees Fahrenheit


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ACKNOWLEDGEMENT AND SIGNATURE PAGE

This Removal Action Workplan (RAW) was prepared by Terra Pacific Group Incorporated. Work associated with this RAW was managed by Mr. Mike Lee of Pacific Gas and Electric Company and was prepared under the auspices of the California Department of Toxic Substances Control’s Project Manager, Mr. Henry Chui.

10/27/11 ______________________________________ _______________ Richard McCartney, P.G. Date Senior Project Manager

10/27/11 ______________________________________ _______________ Max Reyhani, P.E. Date Principal-In-Charge


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EXECUTIVE SUMMARY

This Removal Action Workplan (RAW) was prepared by Terra Pacific Group Incorporated (TPG), on behalf of the Pacific Gas and Electric Company (PG&E), for the portion of the Former Watsonville-1 Manufactured Gas Plant (MGP) occupied by the property located at 618 Main Street in Watsonville, California (hereinafter referred to as the “Property”). This RAW was prepared for submittal to the California Environmental Protection Agency, Department of Toxic Substances Control (DTSC), to comply in part with a Hazardous Substance Site Cleanup Agreement (Docket No. HSA 96/97-029). This RAW was prepared to summarize and evaluate the nature and extent of impact at the Property to support the selection of an appropriate response action.

The Property is located northwest of the intersection of East Fifth Street and Main Street, in the downtown area of the city of Watsonville, California. The County of Santa Cruz lists the Property as Assessor Parcel Number (APN) 018-151-26. The Property was previously part of a larger parcel that was occupied by the Watsonville-1 Former MGP. The Watsonville-1 MGP was originally constructed in 1871 and was shut down in 1905 when another MGP (Watsonville-2) began operation at another location approximately 1-mile to the southeast. From about 1905 to 1931, the property was used for various purposes including: a schoolhouse; automobile painting and trimming shop; an automobile dealership; and an automobile repair shop. In 1931, Coast Counties Gas and Electric Company (CCG&E) constructed the existing restaurant building for use as a customer service center. The northeastern end of the MGP, where gas manufacturing had primarily been conducted, was sold to private parties in 1935. CCG&E continued to use the remaining portion of the Former MGP (subject Property) as a customer service center until it was acquired by PG&E in 1954. PG&E utilized the Property as a customer service center as well until 1989, when it was leased for use as a restaurant. The Property is currently privately owned and is currently occupied by Jalisco’s, a Mexican restaurant.

Since 1985, several environmental studies have been conducted at the Property, including subsurface investigations consisting of soil, soil gas and groundwater sampling, a Human Health Risk Assessment (HHRA), ongoing periodic groundwater monitoring since 1991, and ongoing periodic soil gas monitoring since 2008. These studies have indicated that soil, soil gas and groundwater within the Property are impacted by compounds that may, in part, represent MGP residual wastes. The HHRA concluded that the three major contributors to excess cancer risk were polycyclic aromatic hydrocarbons (PAH) and hexavalent chromium in soil, and benzene in groundwater. The inclusion of hexavalent chromium as a cancer risk factor has since been eliminated based on re-sampling of the area where the single elevated concentration of hexavalent chromium was previously detected. A screening-level vapor intrusion health risk evaluation was subsequently conducted based on the soil gas sampling results from sampling conducted after the completion of the HHRA to address the possibility that volatile chemicals present in the subsurface may migrate upwards via diffusion through the vadose (unsaturated) soil zone, and be transported by advection through cracks, conduits, or seams in the building foundation into the indoor air space of the existing onsite commercial building. Results of the evaluation indicated that levels of volatile organic compounds (VOCs) in the soil gas around the building would be considered safe and acceptable for the current commercial uses of the Property.


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A deed restriction was recorded in 2001 as an interim remedial measure to limit land usage until further evaluation could be performed and a final remedy selected. The removal action goal developed for the Property is to minimize potential future exposure of humans (Property workers and visitors) to the chemicals of concern (COCs) that may be available for ingestion, inhalation, or dermal contact.

Remedial alternatives for soil evaluated as part of this RAW include: No Action; Capping with Institutional Control and Focused Excavation with Offsite Disposal; Removal of Impacted Soil and Offsite Treatment; and Removal of Impacted Soil and Offsite Disposal. Remedial alternatives for soil gas evaluated include: No Action; Soil Gas Monitoring with Institutional Control; and Soil Vapor Extraction and Vapor Treatment, Soil Gas Monitoring and Institutional Control. Remedial alternatives for groundwater evaluated include: No Action; Monitored Natural Attenuation; and In situ Bioremediation.

Based on the detailed evaluation of remedial alternatives, as presented in Section 5.0 of this RAW, the preferred and selected remedial alternative for soil is Capping with Institutional Control and Focused Excavation with Offsite Disposal (Alternative No. 2). This alternative consists of containment, institutional controls, and focused soil excavation to minimize potential future exposure of humans (Property workers and visitors) to carcinogenic PAH (CPAH) that might be available for ingestion, inhalation, or dermal contact. This approach will include the removal of near-surface soil within the landscape planter areas that contain elevated CPAH concentrations and backfilling with clean import soil. The approach will also include replacement of all existing asphalt pavement and the surface water drainage system. The new pavement and clean soil backfill within the planters will collectively constitute a cap to contain or conceal the underlying impacted soil. Once the cap is installed, an operation and maintenance (O&M) plan will be developed to ensure that the cap is properly maintained and functioning as intended. The existing deed restriction (institutional control) will provide a mechanism to further reduce potential exposure to Property users as a result of potential periodic subsurface repair work.

The selected remedial approach for soil gas is Soil Gas Monitoring with Institutional Control (Alternative No. 2). Under this alternative, no active remediation of the impacted soil gas would be conducted. However, soil gas would be sampled from select soil gas probe locations periodically and analyzed for VOCs to monitor soil vapor conditions. An institutional control in the form of the existing deed restriction would then be updated for the property to prohibit the construction of new enclosed building(s) within the area of impact (eastern portion of parking lot).

Soil Gas Alternative No. 3 (Soil Vapor Extraction and Vapor Treatment, Soil Gas Monitoring and Institutional Controls) will be retained as a contingency alternative for soil gas should Soil Gas Monitoring show that soil gas concentrations are increasing and exceeding thresholds to be developed as part of the engineering design. This option includes the installation of a network of vapor extraction wells and collection and treatment system.

The selected remedial approach for groundwater is Monitored Natural Attenuation (Alternative No. 2). Under this alternative, no active remediation of the impacted groundwater would be conducted. However, groundwater would be sampled and analyzed for contaminants and natural attenuation


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parameters to monitor the natural attenuation processes. This approach will include continuation of the existing semi-annual groundwater monitoring program that began in 1997. In addition, In situ Bioremediation (Alternative No. 3) is retained as a contingency alternative in the event that the Monitored Natural Attenuation alternative proves ineffective.


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1.0 INTRODUCTION

1.1 GENERAL INFORMATION This Removal Action Workplan (RAW) was prepared by Terra Pacific Group Incorporated (TPG), on behalf of the Pacific Gas and Electric Company (PG&E), for the portion of the Watsonville-1 Former Manufactured Gas Plant (MGP) occupied by the property located at 618 Main Street in Watsonville, California (hereinafter referred to as the “Property”).

This RAW was prepared for submittal to the California Environmental Protection Agency (Cal/EPA), Department of Toxic Substances Control (DTSC), to comply in part with a Hazardous Substance Site Cleanup Agreement (Docket No. HSA 96/97-029). This RAW was prepared to summarize and evaluate the nature and extent of impact at the Property to support the selection of an appropriate response action.

The Property is located northwest of the intersection of East Fifth Street and Main Street in the downtown area of the city of Watsonville, California (Figure 1-1). The Property is currently occupied by Jalisco’s, a Mexican restaurant (Figure 1-2). The restaurant building was originally constructed in 1931 by the Coast Counties Gas and Electric Company (CCG&E) for use as a customer service center.

1.2 PURPOSE OF THE REMOVAL ACTION WORKPLAN The soil beneath the Property is impacted with MGP-related compounds most notably polycyclic aromatic hydrocarbons (PAHs). The purpose of the RAW is to compile, summarize, and analyze data on the nature and extent of impact such that an appropriate response action can be selected.

1.3 RAW ORGANIZATION This RAW is based on the results of several DTSC-approved reports, prepared by PG&E, CH2M Hill, Smith Technology Corporation (Smith), IT Corporation (IT), Shaw Environmental, Inc. (Shaw), ENV America Incorporated (ENV America), TPG and Iris Environmental. These previous reports include the following:

• Preliminary Assessment of the Former Manufactured Gas Plant Site in the City of Watsonville (PG&E, 1986);

• Preliminary Endangerment Assessment (PEA) (CH2M Hill, 1991); • Site Investigation (SI) Results (IT, 2001); • Human Health Risk Assessment (HHRA) (IT, 2002); • Supplemental Site Investigation (SSI) Report (ENV America, 2004); • Additional Subsurface Investigation Report (TPG, 2009); • Previous groundwater monitoring reports from 1997 through October 2009,

prepared by Smith, Shaw, ENV America and TPG;



• Soil Gas Probe and Groundwater Monitoring Well Installation Report (TPG, 2010b); and

• Draft Screening-Level Vapor Intrusion and Soil Health Risk Evaluation (Iris Environmental, 2010; Appendix A).

The data from previous investigations, as well as the HHRA, the removal action goals and objectives, and the most appropriate remedial alternative for the Property are summarized in this RAW. The contents of this RAW are organized as follows:

Section 1.0 Introductory information.

Section 2.0 Relevant background information including a summary of Property history, ownership and operation, current land usage, previous investigations, and a description of the environmental setting.

Section 3.0 Discussion regarding the nature and extent of impact.

Section 4.0 The development and discussion of proposed removal action goals.

Section 5.0 A summary of the feasible remedial alternatives evaluated and selection of the recommended alternative.

Section 6.0 Overview of the selected remedial alternative.

Section 7.0 Description of the Sampling Plan.

Section 8.0 Description of this project’s status regarding the California Environmental Quality Act (CEQA).

Section 9.0 Overview of future public participation activities.

Section 10.0 A presentation of the tentative proposed remediation implementation schedule.

Section 11.0 A description of requested Property Certification for completion.

Section 12.0 A detailed listing of previous project work and agency involvement.

Section 13.0 A list of cited references.



2.0 BACKGROUND

This section describes the Property’s location, current features and use, historical Property development and operations, geologic and hydrogeologic conditions, and previous investigations. The information in this section was primarily obtained from the Preliminary Assessment (PG&E, 1986), PEA (CH2M Hill, 1991), SI Results Report (IT, 2001), and the HHRA (IT, 2002).

2.1 PROPERTY LOCATION The Property is located in the Pajaro Valley, a low-lying basin that is bordered on the north and south by rolling foothill terrain, within the southernmost end of Santa Cruz County. The ground surface of the Pajaro Valley slopes mildly seaward (west) and is drained by the Pajaro River and its principal tributaries. The Property is located approximately 4.5 miles east of the Pacific Ocean, approximately 90 miles south of downtown San Francisco, and 0.8-mile northwest of the Pajaro River at an approximate elevation of 37 feet above mean sea level (msl).

The Property is listed at an address of 618 Main Street, northwest of the intersection of East Fifth Street and Main Street, in the downtown area of the city of Watsonville, California (Figure 1-1). The County of Santa Cruz lists the Property as Assessor Parcel Number (APN) 018-151-26 (Figure 2-1).

A predominantly commercial and residential area of downtown Watsonville surrounds the Property, which is bordered by a bank to the northwest, a commercial property to the northeast, a market to the southeast, and Main Street to the southwest. Residential properties exist approximately 100 feet north of the Property (CH2M Hill, 1991).

2.2 PROPERTY DESCRIPTION The Property is nearly rectangular in plan view and occupies approximately 0.4-acre of relatively flat-lying land. The Property is currently occupied by Jalisco’s, a Mexican restaurant, which is bordered by an asphalt parking lot and planters (Figure 1-2). The restaurant building, originally constructed in 1931 for use as a customer service center, is listed on the City of Watsonville’s Directory of Historical Resources and is deemed as eligible for listing on the National Register of Historic Places (NRHP).

The restaurant building exists on the southwestern portion of the Property, facing Main Street. A driveway runs along the south side of the building, providing access to the back parking lot from Main Street. The Property is separated from the surrounding properties by wooden fencing (northern boundary), a concrete-block retaining wall/wooden fence (eastern boundary), and a building and shrubbery (southern boundary) (Figure 1-2).

2.3 PROPERTY HISTORY The Property was previously part of a larger parcel that was occupied by the Watsonville-1 Former MGP. The Watsonville-1 MGP was originally constructed in 1871 and was shut down in 1905 when another MGP (Watsonville-2) began operation at another location approximately 1-mile to the southeast. Historical features are shown on Figure 1-2.



In 1871, the Watsonville Maxim Gas Company constructed the Watsonville-1 MGP, which utilized gasoline as the feedstock for producing gas. Soon after the MGP was constructed, an explosion occurred burning several people. The gasoline-fueled MGP was repaired and used until the Spring of 1879, when the MGP was converted to a coal-gas works.

The coal-gas works operated at the Watsonville-1 MGP from 1879 until 1902. During this time period, the MGP was expanded southward to what is now Fifth Street. MGP features included a small gas holder, a structure containing retorts, a purifier, and a scrubber, and a coal shed. Only the gas holder and a portion of the main retorts structure existed within the limits of the Property (Figure 1-2).

Ownership of the Watsonville-1 MGP was transferred from the Watsonville Maxim Gas Company to the Watsonville Gas Company in 1902. The MGP was immediately converted from a coal-gas works to an oil-gas plant and a larger gas holder, a generator building, and two aboveground crude oil tanks were installed on the northeastern portion of the Watsonville-1 MGP, northeast of the Property. Following the conversion, the coal-gas works features were removed.

In 1905 the Watsonville Gas Company was acquired by the Watsonville Light and Power Company. The new owners shut down the Watsonville-1 MGP and opened the Watsonville-2 MGP approximately 1-mile to the southeast on the corner of Walker and Front Streets. The Watsonville-1 MGP was dismantled in 1908.

From about 1905 to 1931, the property was used for various purposes including: a schoolhouse; automobile painting and trimming shop; an automobile dealership; and an automobile repair shop. In 1931, CCG&E constructed the existing restaurant building for use as a customer service center. The northeastern end of the Former MGP, where gas manufacturing had primarily been conducted, was sold to private parties in 1935. CCG&E continued to use the remaining portion of the Former MGP as a customer service center until it was acquired by PG&E in 1954. PG&E utilized the property as a customer service center as well until 1989, when it was leased for use as a restaurant.

To minimize the potential for exposure of contaminants to current and/or future Property users, a Covenant to Restrict Use of Property (deed restriction) was recorded in 2001. PG&E subsequently sold the property to the current restaurant owners in 2001.

2.4 HISTORIC EVALUATION The restaurant building was evaluated for historical significance based on age, historical association, architectural value, and integrity defined under the National Historic Protection Act (NHPA) (ENTRIX, Inc. [ENTRIX], 2004). The building is historically significant, and was designed by Albert F. Roller, a master architect who designed commercial structures in California during the middle portion of the twentieth century. Therefore, the building meets historic designation Criterion C, by representing the work of a master. The property itself is significant since it is associated with development of the gas industry in the Watsonville area, and therefore meets Criterion A, associated with events that have made a significant contribution to the broad patterns of our history. The PG&E building is a direct result of the growth of the manufactured gas industry and the subsequent consumer-oriented power industry in the State, in which PG&E played a major



role. The building retains excellent integrity of setting, materials, and workmanship, feeling, and association with the downtown area. The building continues to convey the significant features of historical architecture that make it such an important component of Main Street, Watsonville. Based on this evaluation, the building appears to be eligible for listing on the NRHP.

The ENTRIX’s historical and architectural report (ENTRIX, 2004) stated that the historical significance of the PG&E building could be impaired if future projects demolish or substantially alter in an adverse manner those physical characteristics that convey its historical significance by diminishing the integrity of the property’s location, design, setting, materials, workmanship, feeling, or association. Adverse effects included, but are not limited to, the following:

• Physical destruction, damage, or alteration of all or part of the property; • Isolation of the property or alteration of the character of the property’s setting when

that character contributes to the property’s qualifications for the NRHP; • Introduction of visual, audible, or atmospheric elements out of character with the

property or changes that may alter its setting; • Neglect of the property, resulting in its deterioration or destruction; and • Transfer, lease, or sale of the property without adequate provisions to protect its

historic integrity.

The report concluded that, in order to avoid or minimize future impacts to the Property, any future projects should incorporate appropriate mitigation measures to minimize and avoid adverse effects to the integrity of the building (ENTRIX, 2004).

2.5 ENVIRONMENTAL SETTING 2.5.1 Geologic Conditions

2.5.1.1 Areal Geology

The Pajaro Valley is a structural depression that is deeply infilled with continental and marine sediments. Intrusive granitic rocks underlie the entire Valley. The San Andreas Fault trends along the eastern boundary of the Pajaro Valley and the subparallel Zayante-Vergeles Faults transect the Valley approximately 1-mile east of Watsonville (Muir, 1972).

The geologic units of the Pajaro Valley area are commonly grouped into consolidated rocks and unconsolidated deposits that generally have non-water-bearing and water-bearing characteristics, respectively. The consolidated materials comprise multiple formations and consist of Cretaceous-age granitic basement rocks that are unconformably overlain by Cretaceous to Miocene marine sediments and some volcanic flows (Muir, 1972). The unconsolidated materials include the Pliocene-age Purisima Formation, the Pleistocene-age Aromas red sands and terrace deposits, and Holocene-age alluvium and dune sands. The unconsolidated units collectively constitute the groundwater basin of the Pajaro Valley.



Alluvium rests directly on the Aromas red sands throughout much of the Pajaro Valley. The alluvium is Holocene in age and consists of a highly variable mixture of unconsolidated gravel, sand, silt, and clay (Muir, 1972). The alluvium has an average thickness of about 150 feet, with a gravel zone comprising approximately the basal 50 feet. Surficial Holocene deposits of dune sands exist along the coast near Monterey Bay. The dune sands are eolian in origin, remain locally active, and are estimated to be less than 100 feet in total thickness (Muir, 1972).

2.5.1.2 Property Geology

Soil encountered at the Property by previous investigators consisted primarily of sandy silt to clayey sand with minor amounts of gravel. It is estimated that the uppermost 2 to 5 feet of soil at the Property consists of anthropogenic fill that was placed during previous grading operations. Based on available information, the fill material primarily consists of reworked alluvium (silts and sand).

2.5.2 Hydrologic Conditions

2.5.2.1 Surface Water Hydrology

The Pajaro River and its principal tributaries dominate the surface-water hydrology of the Pajaro Valley. In addition to the Pajaro River and its tributaries, surface water bodies in the Pajaro Valley include several sloughs and relatively small lakes. No water is imported into the Pajaro Valley and all water supplies originate from local rainfall or from stream flow into the Valley. Diverted surface water constitutes approximately three percent of the water used in the Pajaro Valley (Pajaro Valley Water Management Agency [PVWMA], 2001).

There are no upstream reservoirs or lakes capable of regulating the amount or rate of surface-water flow into the Pajaro Valley. A flood control system, consisting of levees and various channel improvements, was installed in 1949 to provide 50-year flood protection to the Watsonville area. Despite the existing flood control system, the Pajaro River has overflowed its banks several times and caused severely damaging floods.

Since 1940, the United States Geological Survey (USGS) has monitored and recorded the daily streamflow of the Pajaro River where it enters the Pajaro Valley at Chittenden. Since 1940, the annual surface water inflow at the Chittenden gauging station has varied widely; the minimum rate was 766 acre-feet per year (afy) in 1977 and the maximum rate was more than 653,900 afy in 1983 (Raines, Melton & Carella, Inc. [RMC], 2001).

2.5.2.2 Areal Groundwater Hydrology

The water-bearing sediments of the Pajaro Valley consist of a complex sequence of separate hydrogeologic units that are geologically interconnected. These interconnected units effectively function as a single groundwater reservoir that extends from the San Andreas Fault to far offshore beneath the Pacific Ocean.



Fresh groundwater in the Pajaro Valley occurs in the Purisima Formation, Aromas red sands, terrace deposits, alluvium, and dune sand. Both the Purisima Formation and the Aromas red sands contain multiple aquifers that are separated by discontinuous clay interbeds. The Aromas red sands are the most intensely pumped unit in the Pajaro Valley (RMC, 2001).

The alluvium also contains multiple aquifers that are separated by discontinuous clay interbeds. The basal portion of the alluvium consists of a gravel bed that is approximately 50 feet thick. The basal gravel bed is the main water-bearing subunit of the alluvium (Muir, 1972). Throughout much of the Pajaro Valley, the uppermost portion of the alluvium predominantly consists of clay-rich sediments

Infiltration of rainfall into the alluvium is minimal in most areas, due to the preponderance of clay and silt that essentially seals the alluvium from direct surface water recharge (Muir, 1972). The alluvium is, however, recharged in the north and northeast portions of the Pajaro Valley by seepage from the Pajaro River and other streams (Muir, 1972). The current groundwater pumping demand is more than double the current sustainable yield, resulting in a dramatic groundwater deficit (RMC, 2001).

Increased water demand over the last several decades has lowered the potentiometric surface so that it is now below sea level throughout much of the Pajaro Valley. The groundwater flow pattern changes seasonally and annually, but groundwater generally flows toward a pumping trough between Watsonville and the coast. Since there is no barrier between the main aquifers and the ocean, the lowering of the potentiometric surface has resulted in seawater intrusion into the fresh groundwater basin. Seawater has most noticeably impacted the basal gravel unit in the alluvium as well as aquifers in the Aromas red sands (RMC, 2001).

Shallow groundwater exists in the alluvium throughout much of the Pajaro Valley as a semiperched aquifer that is separated from the main groundwater body by shallow beds of clay and silt. In some areas the shallow semiperched groundwater occurs under water table conditions (i.e., unconfined). Much of the shallow semiperched groundwater, as well as groundwater within the deeper aquifers, occurs under pressure conditions (i.e., confined).

Groundwater from the shallow aquifer is probably not directly used, due to apparently low to moderate yield and poor water quality reported as early as 1953. The poor water quality was attributed to the infiltration of irrigation water, organic wastes from domestic septic tanks, and from industrial plants (Muir, 1972). At that time (1953), groundwater from the shallow aquifer contained relatively high total dissolved solid (TDS) content, and individual concentrations of sulfate, nitrate, chloride, and magnesium commonly exceeded 100 milligrams per liter (mg/L) (Muir, 1972).

2.5.2.3 Property Groundwater Hydrology

Since groundwater monitoring was initiated at the Property in 1991, the depth to groundwater has fluctuated between approximately 16 and 32 feet below ground surface (bgs). As would be expected, groundwater elevations are routinely higher in spring months as compared to the fall months. During the recent fall 2009 groundwater monitoring event, the overall groundwater flow



pattern was to the southwest at an approximate hydraulic gradient of 0.10 foot/foot, which is generally consistent with previous monitoring events conducted in the fall.

2.6 PREVIOUS AND ONGOING ENVIRONMENTAL STUDIES Various studies have been conducted for the Property since 1986. This section summarizes previous studies as well as ongoing groundwater and soil gas monitoring activities.

2.6.1 Preliminary Assessment by PG&E, 1986

In 1986 PG&E conducted a Preliminary Assessment of the Former Watsonville-1 MGP to evaluate the environmental conditions of the PG&E-owned portion of the Former MGP, referred to in this document as the “Property” (PG&E, 1986). The investigation included: conducting a title search; reviewing fire insurance maps and company maps; review of historical gas plant production records, local newspaper articles, and video filming; and, the collection of one surface soil sample, MT-408-8-1 (Figure 2-2).

The surface soil sample was collected from a planter bed and was analyzed for PAH, lead, arsenic, mercury, and cyanide. The analytical results indicated that lead (360 milligrams per kilogram [mg/kg]), arsenic (28 mg/kg), and mercury (1.0 mg/kg) were detected in the surface soil sample, while total cyanide was not detected. Total PAH was detected at 5.5 mg/kg. PAH concentrations are summarized in Table 2-1A, and the sampling location is shown on Figure 2-2. Metals concentrations are summarized in Table 2-1B.

2.6.2 Preliminary Endangerment Assessment by CH2M Hill, 1991

A PEA was conducted by CH2M Hill in 1991 to assess the potential human health and environmental risks (CH2M Hill, 1991). During the PEA, five surface soil samples (DSS-WAT1-1 through DSS-WAT1-5) were collected from planter areas (Figure 2-2). Additionally, four soil borings were advanced and sampled with total depths ranging from 20 to 35 feet bgs. Three of these borings, MW-WAT1-1 through MW-WAT1-3, were completed as monitoring wells while boring B-WAT1-1 was backfilled after sampling. Following completion and development, groundwater samples were collected from the three wells. Five offsite, background soil samples (DSS-WAT1-6 through DSS-WAT1-10) were collected from public right-of-way locations within ¼-mile of the Property (Figure 2-3).

Samples retrieved during the PEA were analyzed for one or more of the following: polychlorinated biphenyls (PCBs); volatile organic compounds (VOCs); metals; pH; total cyanide; PAHs; total phenols; purgeable total petroleum hydrocarbons (TPH-p) quantified as gasoline (TPHg); extractable total petroleum hydrocarbons (TPH-e) quantified as diesel (TPHd) and motor oil (TPHmo); ammonia; and total sulfides. Groundwater samples were also analyzed for alkalinity, conductivity, chloride, sulfate, and TDS. Analytical results for onsite soil samples, background soil samples and groundwater samples are summarized in Tables 2-1A through 2-1E, 2-2A through 2-2D, and 2-3A and 2-3B, respectively. Approximate sampling locations are shown on Figures 2-2 and 2-3.



As part of the PEA, baseline human health and environmental risk assessments were conducted. The HHRA concluded that chemicals identified at the Property did not constitute an immediate threat to human health or the environment. The PEA recommended that additional investigations be conducted to determine the extent of PAH, VOCs, and total petroleum hydrocarbons (TPH) in the soil. Though emergency soil removal at the Property was determined to be unnecessary, the PEA recommended an interim removal action to prevent exposure to surface soil from the onsite planters.

2.6.3 Community Profile by IT Corporation, 2000 and Craig Communications, 2009

In 2000, a Site-specific Community Profile Report summarizing the Property setting and demographics of the community was submitted to the DTSC (IT, 2000). The purpose of the Community Profile Report was to assist the DTSC in assessing the potential level of community interest in the investigation activities and in determining suitable public participation activities for continuing work at the Property. The Community Profile summarized Site history, land use, previous investigations, chemicals of potential concern (COPCs), surrounding property uses, and demographics of the community. Other issues such as community interest, potential project impacts, and recommended public participation were also addressed.

In 2009, an updated Community Profile was prepared by Craig Communications to address public participation needs for investigation and remediation work that is planned for the near future (Craig Communications, 2009). The purpose of the updated Community Profile was to: (1) provide a description of the Property and the community in which it is located, (2) determine initial community interest in investigation and cleanup activities, and (3) recommend future public participation activities to ensure that interested community members are kept informed about the Property investigation and cleanup process. The updated Community Profile also summarized the results of a community survey conducted in September 2009. Based on the community survey response, the fact that the Property is located in a commercial area and is separated physically and visually from surrounding properties with fences and hedges, it is anticipated that there will be low interest in any environmental work at the Property.

2.6.4 Site Investigation by IT Corporation, 2001

An SI was conducted by IT in 2001 to further identify and delineate the nature and extent of COPC (IT, 2001). As part of the SI, IT advanced nine shallow hand auger borings (SS-WAT1-1 through SS-WAT1-9) within onsite planters, advanced two deeper hollow-stem auger borings (B-WAT1-2 and B-WAT1-3), and installed two additional groundwater monitoring wells (MW-WAT1-4 and MW-WAT1-5). Soil samples were collected during drilling and two groundwater grab samples were also collected from the deeper hollow-stem auger boring locations. Following the installation and development of the monitoring wells, semi-annual groundwater monitoring was conducted (MW-WAT1-1 through MW-WAT1-5). Sampling locations and groundwater monitoring wells are shown on Figure 2-2.

The SI included the analysis of 32 soil samples (excluding duplicates), five groundwater monitoring well samples (both filtered and unfiltered), and two groundwater grab samples. Samples were analyzed for one or more of the following: PAH; TPH-e (as TPHd and TPHmo); TPH-p (as TPHg);



benzene, toluene, ethylbenzene, and total xylenes (BTEX); methyl tertiary-butyl ether (MTBE); arsenic; hexavalent chromium; cyanide; ammonia; and, phenols. Analytical results for onsite soil samples are summarized in Tables 2-1A through 2-1E. Approximate sampling locations are shown on Figure 2-2. Historical groundwater quality data is summarized in Tables 2-3A and 2-3B.

As a part of the SI, the basement of the onsite building was inspected for cracks and any evidence of water damage. A visual inspection of the accessible areas of the basement did not reveal any evidence of water damage or cracks.

2.6.5 Human Health Risk Assessment by IT Corporation, 2002

In 2002, IT prepared a HHRA to evaluate the potential human health effects of exposure to onsite chemicals in soil and groundwater (IT, 2002). Based on the existing deed restriction, the current and future land use scenarios were assumed to be commercial and industrial with associated receptors including current gardener workers, current and future commercial/industrial workers, future construction workers, and hypothetical offsite residential adults and children. Potentially complete exposure pathways (inhalation, dermal contact, ingestion) were evaluated for each receptor.

Following the evaluation of the Site-specific exposure scenarios, a toxicity assessment and risk characterization were conducted for each of the aforementioned scenarios, receptors, and exposure pathways. The HHRA concluded that the cancer risks (between 1x10-4 and 1x10-6) and the non-cancer hazard indices (HIs) (below 1) were within the “risk management range” established by the United States Environmental Protection Agency (USEPA). However, the receptor-specific risks were greater than the DTSC’s point of departure of 1x10-6. The three major contributors to the excess cancer risk (above 1x10-6) were PAH (primarily benzo[a]pyrene) and hexavalent chromium in soil, and benzene in groundwater.

2.6.6 Conceptual Remedy for the Watsonville-1 MGP Site by Shaw, 2003

On behalf of PG&E, Shaw prepared a memorandum entitled “Conceptual Remedy for the Watsonville-I MGP Site,” dated March 3, 2003 (Shaw, 2003). The memorandum conceptually summarized a mitigative alternative to reduce potential exposure to receptors identified in the HHRA (IT, 2002). The memorandum proposed the removal and replacement of shallow soil within the planter areas and the replacement of surface pavements to contain the PAH and hexavalent chromium that may otherwise be available for ingestion, inhalation, or dermal contact. Based on a general decreasing trend of benzene concentrations in groundwater and on the relative distance of benzene-impacted groundwater (approximately 55 feet) from the building, Shaw’s memorandum proposed a long-term monitoring alternative for benzene in the groundwater.

2.6.7 Supplemental Site Investigation by ENV America, 2004

ENV America conducted an SSI in May 2004 to further define the nature and extent of impacted soil (ENV America, 2004). The SSI included the advancement of 10 shallow hand auger borings (HA1 through HA10) within the onsite planters and four deeper direct-push borings (GP1 through GP4) within the paved area of the Property. Soil samples were analyzed for one or more of the following: PAH; hexavalent chromium; TPH-p (as TPHg), TPH-e (as TPHd and TPHmo); and



BTEX. Boring locations are depicted on Figure 2-2. Analytical results for onsite soil samples are summarized in Tables 2-1A through 2-1E.

To either verify or refute the single elevated concentration of hexavalent chromium (24.8 mg/kg) detected during the PEA (CH2M Hill, 1991), boring HA9 was advanced in approximately the same location as surface sample DSS-WAT1-3. Samples retrieved from boring HA9 were analyzed for hexavalent chromium by USEPA Method 7199, which is considered a more reliable method than the USEPA Method 7196A that was used during the PEA. The maximum concentration of hexavalent chromium detected in boring HA9 was 0.26 mg/kg, which is well below the USEPA’s Preliminary Remediation Goal (PRG) for residential soil of 30 mg/kg and is two orders of magnitude below the concentration of 24.8 mg/kg previously detected at the same location by CH2M Hill (1991). Hexavalent chromium was only detected in one of the 40 samples of onsite soil previously analyzed, and there is no known source of hexavalent chromium at the Property. Accordingly, ENV America concluded that the concentration of hexavalent chromium previously detected by CH2M Hill (1991) in surface sample DSS-WAT1-3 (24.8 mg/kg) was likely invalid and should require no further action.

The SSI also concluded that the Property had been sufficiently characterized and that a mitigative action to reduce potential exposure to PAH-impacted soil would be necessary in the northeast portion of the Property.

2.6.8 Additional Subsurface Investigation by TPG, 2008

TPG conducted an additional subsurface investigation in February 2008 to investigate the potential presence of vapor-phase organic constituents in subsurface soils and to provide additional soil data to supplement the existing characterization dataset at the Property (TPG, 2009). The investigation included advancing and sampling five direct-push borings (TPG-1 through TPG-5) and installing and sampling seven semi-permanent soil gas probes (SG-1 through SG-7) within various portions of the Property (Figure 2-2). Soil gas probes were installed at depths of 5 and 15 feet bgs at six locations (SG-2 through SG-7) and at a depth of 5 feet bgs only at one location (SG-1). Each soil sample was analyzed for PAHs, TPH-e (as TPHd and TPHmo), TPH-p (as TPHg) and California Assessment Manual (CAM) metals. Soil gas samples were analyzed for VOCs. Boring and soil gas probe locations are depicted on Figure 2-2. Analytical results for onsite soil samples are summarized in Tables 2-1A through 2-1E and analytical results for soil gas samples are summarized on Table 2-4. Subsequent to sampling, the soil gas probes were destroyed.

Soil sampling results were generally consistent with previous investigations findings. The highest VOCs detected in soil gas samples collected at the Property were encountered at probes SG-4, SG-5, SG-6 and SG-7, in the eastern portion of the parking lot, consistent with areas of elevated soil impacts encountered during this and previous investigations. The results of VOC analyses from locations immediately adjacent to the building, probes SG-1, SG-2 and SG-3, were reported at relatively low concentrations (Table 2-4).



2.6.9 Soil Gas Probe and Groundwater Monitoring Well Installation by TPG, 2009

TPG installed nine dual-depth soil gas probes and two monitoring wells in October 2009 to: (1) provide new permanent soil gas probes to enable the initiation of a semi-annual soil vapor sampling program, and augment currently available soil gas data, and (2) provide additional groundwater monitoring wells to supplement the existing onsite well network which is currently included in the ongoing semi-annual groundwater monitoring program (TPG, 2010b).

Dual-depth permanent soil gas probes were installed at depths of 5 and 15 feet bgs at eight locations (SG-2A through SG-6A, SG-8 through SG-10) and at depths of 5 and 9 feet bgs at one location (SG-1A). Two additional groundwater monitoring wells (MW-WAT1-6 and MW-WAT1-7) were installed, each with a screen depth interval of 19 to 34 feet, to obtain supplemental groundwater quality data along the northeastern portion of the building. Soil samples collected from the well borings were analyzed for physical parameters including moisture content, grain size, specific gravity, wet and dry density and porosity. Physical testing results for soil samples are summarized in Table 2-1F. Soil gas probe and monitoring well locations are depicted on Figure 2-2.

Sampling of the soil gas probes and the two new wells have been incorporated into the ongoing semi-annual groundwater and soil gas monitoring program, as described in Sections 2.6.10 and 2.6.11 below.

2.6.10 Soil Gas Monitoring

In February 2008, seven semi-permanent soil gas probes (SG-1 through SG-7) were installed and sampled, and subsequently destroyed after sampling was completed. In October 2009, nine permanent soil gas probes (SG-1A through SG-6A, SG-8 through SG-10) were installed, and subsequently sampled as part of a new semi-annual monitoring program. The results of the first semi-annual soil gas monitoring event (Fall 2009) is discussed below (TPG, 2010a).

As discussed above, soil gas sampling was conducted in February 2008 and in October 2009. Soil gas samples (and duplicates) collected during each of these two events were analyzed for VOCs (including naphthalene) by USEPA Method 8260B. Confirmation soil gas samples were collected from selected probes and analyzed for VOCs (including naphthalene) by USEPA Method TO-15. In addition, soil gas samples (and duplicates) collected from the nine permanent probes (Fall 2009) were also analyzed for TPHg by the same methods. Soil gas analytical results from both sampling events are summarized in Table 2-4. The results of soil gas sampling at the Property are summarized in Section 3.3.

In 2009, a Soil Gas Contingency Plan was prepared to present steps to be taken in the unlikely event that elevated impacts are found in soil gas samples collected adjacent to the restaurant building during the implementation of soil gas sampling at the Property (TPG and Iris Environmental, 2009). The Contingency Plan presents risk-based soil gas screening levels developed for the Property. During the implementation of soil gas sampling at the Property, soil gas results from probes nearest the building (SG-1A, SG-2A, SG-3A and SG-8) are compared to the screening levels. The Contingency Plan further outlines the steps to be taken if these screening levels are exceeded, including potential subslab sampling and indoor air sampling.



To-date, soil gas sample results have not exceeded any action levels outlined in the Contingency Plan.

2.6.11 Groundwater Monitoring

Groundwater monitoring wells MW-WAT1-1, MW-WAT1-2, and MW-WAT1-3 were installed and initially monitored and sampled in 1991. Semi-annual sampling was initiated at the Property in October 1997. Two additional monitoring wells, MW-WAT1-4 and MW-WAT1-5, were installed and incorporated into the groundwater monitoring program in March 2001. Thereafter, two more monitoring wells, MW-WAT1-6 and MW-WAT1-7, were installed and incorporated into the semi-annual groundwater monitoring program in October 2009.

Since the onset of groundwater monitoring in 1991, the depth to groundwater has fluctuated between approximately 16 and 32 feet bgs. As would be expected and with few exceptions, groundwater elevations are routinely higher in spring months as compared to the fall months. Groundwater elevation data from the October 2009 monitoring event indicate that groundwater flows generally in a westerly to northwesterly direction at an approximate hydraulic gradient of 0.10 foot/foot (TPG, 2010a).

Since 1991, groundwater samples have regularly been analyzed for PAH, TPH-p (as TPHg), TPH-e (as TPHd and TPHmo), BTEX, and MTBE. Periodically, samples have also been analyzed for cyanide, ammonia, arsenic, hexavalent chromium, phenolics, and TDS. Groundwater analytical results from previous sampling events are summarized in Tables 2-3A and 2-3B.

The results of groundwater sampling at the Property are summarized in Section 3.4.

2.6.12 Screening-Level Risk Evaluation by Iris Environmental, 2010

A screening-level vapor intrusion health risk evaluation was conducted based on the soil gas sampling results of the additional subsurface investigation (TPG, 2009) and the October 2009 sampling event (TPG, 2010a) to address the possibility that volatile chemicals present in the subsurface may migrate upwards via diffusion through the vadose (unsaturated) soil zone, and be transported by advection through cracks, conduits, or seams in the building foundation into the indoor air space of the existing onsite commercial building (Iris Environmental, 2010). In addition, DTSC had requested that Property soil data from several previous investigations from 1986 to 2008 be compared to screening levels. This evaluation consisted of comparing maximum soil concentration data against published risk-based screening levels from Cal/EPA and USEPA and, for some chemicals, against background levels.

The results of the screening-level risk evaluation are include in Appendix A. The risk evaluation found that in the “worst case scenario” screen, the estimated incremental cancer risk to onsite commercial workers, associated with inhalation of volatile COPCs (i.e., detected VOCs in soil gas) present in indoor air as a result of vapor intrusion into the existing building, is 4.6×10-7, which is below the 1×10-6 risk threshold. The estimated noncancer hazard index under the worst case scenario is 1.9×10-2, which is two orders of magnitude below the threshold value of 1.0. Therefore,



it may be concluded from this assessment that levels of VOCs in the soil gas around the existing building would be considered safe and acceptable for the current commercial uses of the Property.

In addition, the screening-level vapor intrusion health risk evaluation included an assessment of possible exposure to residents present in a hypothetical future onsite residential building. The worst-case estimated cancer risk to future hypothetical residents, associated with inhalation of volatile COPCs present in indoor air as a result of vapor intrusion, is 5.5×10-4, of which 60 percent is attributable to naphthalene and 22 percent is attributable to benzene. This future hypothetical result is slightly above the 1×10-6 to 1×10-4 risk management range. The future hypothetical worst-case estimated noncancer hazard index is 32, which is above the threshold level of 1.0. The screening-level soil health risk evaluation supports that the deed restriction is needed until the time at which further evaluations support that property conditions are safe and protective of future residential land use.

The primary constituents in soil that exceed applicable direct-contact commercial screening criteria (or background concentrations, where background concentrations are known to be greater than risk-based screening criteria) are carcinogenic PAHs (CPAHs). The evaluation concluded that any proposed remedy that effectively precludes the potential for direct contact, such as a cover or cap over the impacted soils, will protect current commercial workers from potential adverse health effects that could result from these direct exposures. In the event that the deed restriction was ever to be removed from the Property, and residential development considered, additional risk-based evaluations of the soil constituents would be warranted.

2.7 DEED RESTRICTION In 2001, deed restrictions were placed on the Property to minimize the potential for human exposure to subsurface contaminants and to prohibit the use of the property for residential purposes. A land use covenant was recorded on January 26, 2001 and is included in Appendix B.



3.0 NATURE AND EXTENT OF IMPACT

3.1 INTRODUCTION The chemicals typically associated with former MGP sites include PAH, select inorganics (e.g., some trace metals and cyanide), BTEX and TPH. The PAH from lampblack and tars generated from gas manufacturing processes are the typical indicator chemicals used to direct the investigation and remediation of MGP sites.

The discussion below regarding the nature and extent of impact at the Property is based on the analytical data generated from the various phases of investigations that were described in Section 2.6, as well as upon field observations made during those investigations. The subsections below present a summary of the findings for each category of contaminants detected at the Property. Tables 2-1A through 2-1E, 2-2A through 2-2D, 2-3A and 2-3B, and 2-4 summarize the onsite soil analytical results, the background soil analytical results, the groundwater analytical results, and the soil gas analytical results, respectively.

3.2 SOIL Carcinogenic Polycyclic Aromatic Hydrocarbons

As indicated earlier, PAHs are common constituents from historical gas manufacturing processes. Accordingly, nearly all samples selected for analyses were tested for PAHs using USEPA Methods 8310 or 8270SIM. Carcinogenic PAHs (CPAHs) include benzo(a)anthracene, benzo(a)pyrene, benzo(b)fluoranthene, benzo(k)fluoranthene, chrysene, dibenzo(a,h)anthracene, and indeno(1,2,3-c,d)pyrene. Naphthalene has recently been re-classified from a non-carcinogenic compound to a carcinogenic compound by the Cal/EPA. Non-carcinogenic PAHs include acenaphthalene, acenaphthene, anthracene, benzo(g,h,i)perylene, fluoranthene, fluorene, phenanthrene, and pyrene.

To collectively evaluate the CPAH compounds, a toxicity equivalency approach was employed in accordance with criteria set forth by Cal/EPA ( Cal/EPA, 1994). The relative degree of toxicity of each individual compound is weighted relative to the most potent CPAH (benzo[a]pyrene) and then summed to calculate benzo(a)pyrene (B[a]P) equivalent concentrations using the potency equivalency factors list below.

Factors Used to Calculate CPAH Expressed in B(a)P Equivalent Concentrations

Compound Potency Equivalency Factor(a)

Benzo(a)pyrene 1.0 Benzo(a)anthracene 0.1 Benzo(b)fluoranthene 0.1 Benzo(k)fluoranthene 0.1 Chrysene 0.01 Dibenzo(a,h)anthracene 0.34 Indeno(1,2,3-c,d)pyrene 0.1

(a)Cal/EPA, 1994 Appendix 1



The results of all PAH analyses for onsite soil and background soil samples are presented in Tables 2-1A and 2-2A, respectively. The CPAH concentrations for onsite soil, in B(a)P equivalent concentrations, are plotted on Figure 3-1. Concentrations of PAHs, expressed in B(a)P equivalent concentrations, for soil shallower than 5 feet bgs ranged from non-detectable to 17.161 mg/kg detected at boring GP1. The B(a)P equivalent concentrations for soil samples greater than or equal to 5 feet bgs ranged from non-detectable to 21.035 mg/kg detected at boring GP1. Elevated B(a)P equivalent concentrations (greater than 0.9 mg/kg) were detected to a maximum depth of 20 feet bgs. The highest CPAH concentrations for soil were detected in soil samples collected from the northeastern portion (rear) of the Property. Based on the presence of elevated CPAH concentrations along the northeastern boundary of the Property, it appears that impacts to soil extend upgradient onto the remaining portion of the former MGP outside of the Property.

Naphthalene

Albeit naphthalene is now classified as a carcinogen, it is discussed separately from the other CPAH since naphthalene is not included in the calculation of B(a)P equivalent concentrations. All naphthalene analyses from onsite soil samples are listed with the other PAH compounds in Table 2-1A. Naphthalene concentrations ranged from non-detectable to 320 mg/kg detected at boring GP4. Elevated naphthalene concentrations were generally collocated with elevated B(a)P equivalent concentrations. The highest naphthalene concentrations were detected in soil samples collected from the northeastern portion (rear) of the Property. Based on the presence of elevated naphthalene concentrations along the northeastern boundary of the Property, it appears that impacts to soil extend upgradient onto the remaining portion of the former MGP outside of the Property.

Total Petroleum Hydrocarbons

Samples from the PEA, SI, and SSI were analyzed for TPHg and TPHd using USEPA Method 8015M. Samples from the SI and SSI were also analyzed for TPHmo using USEPA Method 8015M. Samples from the additional subsurface investigation were analyzed for TPHd and TPHmo using USEPA Method 8015M and TPHg using USEPA Method 8260B/5035. PEA samples were additionally analyzed for total recoverable petroleum hydrocarbons (TRPH) using USEPA Method 418.1. TPH and TRPH concentrations for onsite and background soil samples are summarized in Tables 2-1C and 2-2B, respectively.

Concentrations of TPHg ranged from non-detectable to 5,300 mg/kg detected at boring GP1. The highest concentrations of TPHg were detected at 13 to 15 feet bgs in borings MW-WAT1-3, GP1, and GP4, located in the rear portion of the Property. The maximum TPHg concentration detected in shallow soil (less than 5 feet bgs) was 8.1 mg/kg in surface sample DSS-1-WAT1-2. Background TPHg concentrations ranged from non-detectable to 1.3 mg/kg detected in surface sample DSS-1-WAT1-7.

TPHd concentrations ranged from non-detectable to 14,000 mg/kg detected at boring GP1. The highest concentrations of TPHd were detected at 13 to 20 feet bgs in borings MW-WAT1-3, GP1, and GP4, located in the rear portion of the Property. The maximum TPHd concentration detected



in shallow soil (less than 5 feet bgs) was 2,100 mg/kg in boring GP1 at 2.5 feet. TPHd was not detected in any of the five background samples analyzed as part of the PEA.

Concentrations of TPHmo ranged from non-detectable to 9,500 mg/kg (at boring GP1 at 15 feet bgs). The maximum TPHmo concentration detected in shallow soil (less than 5 feet bgs) was 4,200 mg/kg in boring GP1 at 2.5 feet. Background samples, collected during the PEA, were not analyzed for TPHmo.

TRPH concentrations ranged from non-detectable to 673 mg/kg in the samples analyzed during the PEA. The highest TRPH concentrations were detected in boring MW-WAT1-3 between 13 and 18 feet bgs. The maximum TRPH concentration detected in shallow soil (less than 5 feet bgs) was 141 mg/kg in boring MW-WAT1-2 at 4 feet bgs. Concentrations of TRPH detected in background soil samples ranged from 27.1 mg/kg detected in surface sample DSS-1-WAT1-6 to 364 mg/kg detected in surface sample DSS-1-WAT1-7.

With the exception of one sample, collected from boring GP1 at a depth of 20 feet bgs, all soil samples containing the highest TPH concentrations also contain elevated PAH concentrations.

Benzene, Toluene, Ethylbenzene, Total Xylenes, and Methyl Tertiary-Butyl Ether

Soil samples collected during the PEA were analyzed for toluene, ethylbenzene, and total xylenes using USEPA Method 8020. Samples collected during the SI and SSI were analyzed for BTEX and MTBE using USEPA Method 8021B/5035 while samples collected during the additional subsurface investigation were analyzed for BTEX using USEPA Method 8260B/5035.

Benzene was detected at very low levels (i.e., below the reporting limit) in soil samples collected only during the additional subsurface investigation conducted in 2008, primarily because method detection limits (MDLs) were lower for samples analyzed during that investigation compared to previous investigations. Toluene, ethylbenzene, and total xylenes were generally not detected above their MDL except for samples collected during the additional subsurface investigation for the same reason as described for benzene. The maximum concentrations of toluene (19 mg/kg), ethylbenzene (28 mg/kg), and total xylenes (400 mg/kg) were detected in the 15-foot sample from boring GP1. MTBE was not detected above the MDL in any sample analyzed for MTBE. BTEX and MTBE concentrations for onsite soil samples are summarized in Table 2-1D. Background soil samples were not analyzed for any of these compounds.

Arsenic

Soil samples collected during the PEA, SI and additional subsurface investigation were analyzed for arsenic using USEPA Methods 7060 or 6010B. Concentrations ranged from non-detectable to 10.3 mg/kg in surface sample DSS-WAT1-3. Background soil sample concentrations ranged from 1.25 mg/kg in surface sample DSS-WAT1-10 to 27 mg/kg in surface sample DSS-WAT1-8. Arsenic concentrations for onsite and background soil samples are summarized in Tables 2-1B and 2-2C, respectively.



Hexavalent Chromium

Soil samples collected during the PEA and SI were analyzed for hexavalent chromium using USEPA Method 7196. With the exception of surface sample DSS-WAT1-3 (with a 24.8 mg/kg detection), hexavalent chromium was not detected in any of the other samples analyzed during the PEA or the SI. Hexavalent chromium was detected in one background sample, DSS-WAT1-9, at a concentration of 12 mg/kg during the PEA.

As part of the SSI, soil samples from boring HA9 were analyzed for hexavalent chromium using USEPA Method 7199 to confirm the concentration of 24.8 mg/kg that was previously reported in surface sample DSS-WAT1-3 (CH2M Hill, 1991). Hexavalent chromium was detected at a maximum concentration of 0.26 mg/kg in boring HA9 at 1 foot bgs. This concentration is two orders of magnitude below the concentration previously detected in the same location (DSS-WAT1-3). Since the USEPA Method 7196 previously used to analyze hexavalent chromium is considered to be less reliable than the USEPA Method 7199 used during the SSI, the concentration previously reported for sample DSS-WAT1-3 at 24.8 mg/kg appears to be invalid. Hexavalent chromium concentrations for onsite and background soil samples are summarized in Tables 2-1B and 2-2C, respectively.

Ammonia

Soil samples collected during the PEA were analyzed for ammonia using USEPA Method 350.2 and concentrations ranged from non-detectable to 375 mg/kg detected at boring MW-WAT1-3. The highest concentrations were detected between 13 and 20 feet bgs in borings MW-WAT1-2 and MW-WAT1-3, advanced along the northeastern boundary of the property. SI soil samples were analyzed using USEPA Method 350.3. With the exception of one concentration of 5.6 mg/kg, ammonia was not detected in the SI samples. Background soil samples, collected during the PEA, were analyzed for ammonia using USEPA Method 350.2. Concentrations ranged from 15.3 mg/kg in surface sample DSS-WAT1-10 to 18.1 mg/kg in surface sample DSS-WAT1-9. Ammonia concentrations for onsite and background soil samples are summarized in Tables 2-1E and 2-2D, respectively.

Cyanide

Soil samples collected during the PEA and SI were analyzed for cyanide using USEPA Methods 335.2 or 9010B, respectively. PEA samples ranged from non-detectable to 14.3 mg/kg detected at boring MW-WAT1-2. Cyanide was only detected in two of the thirty-two SI soil samples, at concentrations of 0.62 mg/kg and 0.78 mg/kg at borings SS-WAT1-4 and SS-WAT1-5, respectively. Cyanide was not detected in any of the background soil samples. Cyanide concentrations for onsite and background soil samples are summarized in Tables 2-1E and 2-2D, respectively.

Sulfide (Extractable)

Soil samples collected during the PEA were analyzed for extractable sulfide using USEPA Method 376.1. Sulfide was only detected in one onsite soil sample at a concentration of 3.05 mg/kg



in boring MW-WAT1-1 at 8 feet bgs. Sulfide was not detected in any of the background samples analyzed. Sulfide concentrations for onsite and background soil samples are summarized in Tables 2-1E and 2-2D, respectively.

Total Phenols

Onsite soil samples collected during the PEA were analyzed for total phenols using USEPA Method 420.1. Phenol concentrations ranged from non-detectable to 10.9 mg/kg in boring MW-WAT1-3 at 13 feet bgs. Total phenol concentrations for onsite soil samples are summarized in Table 2-1E.

PCBs

PEA surface samples DSS-WAT1-1 through DSS-WAT1-10 were analyzed for PCBs compounds 1016, 1221, 1232, 1242, 1248, 1254, and 1260. PCBs were not detected in any of the onsite samples analyzed. Background soil sample DSS-WAT1-9 reported the only detection of a PCB compound: Aroclor 1260 at a concentration of 210 micrograms per kilogram (µg/kg).

3.3 SOIL GAS

In February 2008, an initial soil gas survey was conducted at the Property. Semi-permanent soil gas probes were installed at depths of 5 and 15 feet bgs at six locations (SG-2 through SG-7) and at a depth of 5 feet bgs only at location SG-1 (Figure 2-2). At probe SG-1, a soil gas probe was not installed at a depth of 15 feet bgs as originally planned because water was observed in the boring at a depth of 13 feet bgs. All the probes were subsequently destroyed after sampling was completed. In October 2009, nine permanent soil gas probes (SG-1A through SG-6A, SG-8 through SG-10) were installed at depths of 5 and 15 feet bgs, except for the deeper depth at probe SG-1A, which was set at 9 feet bgs due to water being observed at 13 feet bgs. These nine probes were subsequently sampled in conjunction with the semi-annual groundwater sampling program. All soil gas samples were analyzed for TPHg and VOCs (including naphthalene) by an onsite mobile analytical laboratory using USEPA Method 8260B. Confirmation samples were analyzed by an offsite stationary laboratory using USEPA Method TO-15. Analytical results for soil gas samples are summarized on Table 2-3.

In October 2009 sampling event, TPHg and one or more VOCs were detected in soil gas samples collected from each probe location, with the exception of probes SG-2A and SG-8. In general, the highest TPHg and VOC concentrations (including benzene and naphthalene) detected at the Property were encountered at probe locations SG-4A and SG-6A in the upgradient eastern portion of the parking lot. At both of these locations, elevated soil impacts were also encountered during previous investigations. In the western portion of the Property (e.g., SG-1A, SG-2A, SG-3A and SG-8), soil gas VOCs, if detected, were reported at concentrations significantly lower than those reported at locations SG-4A and SG-6A. The analytical results for soil gas samples collected from paired soil gas probe locations (e.g., SG-1 and SG-1A) during the February 2008 and October 2009 were generally consistent, suggesting that the soil gas plume is stable.



3.4 GROUNDWATER

Groundwater monitoring wells MW-WAT1-1, MW-WAT1-2, and MW-WAT1-3 were installed and initially monitored and sampled in 1991 as part of the PEA. Semi-annual sampling was initiated at the Property in October 1997. Two additional groundwater monitoring wells, MW-WAT1-4 and MW-WAT1-5, were installed and incorporated into the groundwater monitoring program in March 2001. Also, two additional monitoring wells, MW-WAT1-6 and MW-WAT1-7, were installed and incorporated into the groundwater monitoring program in October 2009.

Since 1991, groundwater samples have regularly been sampled and analyzed for PAH, TPH-p (as TPHg), TPH-e (as TPHd and TPHmo), BTEX, and MTBE. Periodically, samples have also been analyzed for cyanide, ammonia, arsenic, hexavalent chromium, phenolics, and TDS. Analytical results for groundwater samples are summarized in Tables 2-3A and 2-3B.

In general, the highest concentrations of BTEX, PAHs, ammonia (as nitrogen) and total cyanide have been detected in groundwater samples from well MW-WAT1-3, located on the northeastern portion of the Property. TPHd, and ammonia (as nitrogen) have also been detected in the groundwater samples from wells MW-WAT1-4 and MW-WAT1-6. However, during the October 2009 monitoring event, the initially high concentrations of TPHd and TPHmo detected in the groundwater sample from newly installed well MW-WAT1-6 were suspected to largely represent waste animal and vegetable oils because of the proximity of well MW-WAT1-6 to the onsite restaurant kitchen. As such, the groundwater sample from well MW-WAT1-6 were re-analyzed for TPHd and TPHmo with a silica-gel cleanup and reported at concentrations significantly lower than the initial results, and lower than the TPHd concentration detected in the sample from upgradient well MW-WAT1-3. No chemicals were detected in the groundwater samples collected at the three downgradient wells (MW-WAT1-1, MW-WAT1-5, and MW-WAT1-7) during the October 2009 monitoring event.

The overall distribution of detected chemicals reported in groundwater indicates that impacted groundwater is generally limited to the northeastern portion of the Property in the vicinity of wells MW-WAT1-3, MW-WAT1-4, and MW-WAT1-6. Over the last 19 years, the concentrations of detectable analytes have generally followed an overall decreasing trend. However, seasonal fluctuations consist of relatively higher analyte concentrations in the spring months, when groundwater elevations are higher, compared to lower analyte concentrations in the fall months. In 2009, decreasing concentrations of select compounds such as TPHd, TPHg and BTEX were observed during the October sampling event as compared to the preceding April sampling event, where increases in the concentrations of these chemicals were noted. These compounds continue to be non-detect at the downgradient wells (MW-WAT1-5 and MW-WAT1-7), indicating that the contaminant plume appears to remain localized and stable.



4.0 REMOVAL ACTION GOALS

4.1 OVERVIEW As discussed above, the HHRA (IT, 2002) concluded that the receptor-specific risks and HIs associated with direct exposure to soil and indirect exposure to groundwater were within the USEPA’s risk range of 1x10-4 and 1x10-6 and below the target level of 1, respectively. However, the receptor-specific risks were greater than the DTSC’s point of departure of 1x10-6. The HHRA indicated that the three major contributors to the excess cancer risk were PAH (primarily benzo[a]pyrene) and hexavalent chromium in soil, and benzene in groundwater. The inclusion of hexavalent chromium as a cancer risk factor has since been eliminated based on re-sampling of the area where the single elevated concentration of hexavalent chromium was previously detected.

In addition, the recent screening-level risk evaluation (Iris Environmental, 2010) found that, under a worst case scenario, the estimated incremental cancer risk to current onsite commercial workers, associated with inhalation of volatile COPCs present in indoor air as a result of vapor intrusion, is 4.6x10-7. Despite this risk being below the DTSC’s point of departure of 1x10-6, the soil gas medium is still being evaluated in this RAW to allow the development of a contingency plan under the unlikely scenario that soil gas concentrations increase in the future.

A deed restriction was recorded in 2001 as an interim remedial measure to limit land usage until further evaluations could be performed and a final remedy selected (Appendix B). The Deed may be amended, if necessary, to address a change in conditions at the Property due to remediation. The removal action goal (RAG) developed for the Property is to minimize potential future exposure of humans (Property workers and visitors) to the chemicals of concern (COCs) that may otherwise be available for ingestion, inhalation, or dermal contact.

4.2 SOIL Removal actions for soil could be used to eliminate or ease land-use restrictions. For the purposes of this study, an action level for CPAH of 1 mg/kg B(a)P equivalent concentrations was selected to allow a comparison of costs for the various remedial alternatives. This criterion was generally based on target cleanup levels used for other MGP sites in California that were successfully remediated to background PAH concentrations. This action level was not based on a specific risk-based scenario, but is sufficiently low to profile approximate costs for remediation to meet a less restricted Property use.

4.3 SOIL GAS Soil gas sampling data indicates that elevated COPC concentrations, including benzene and naphthalene, are present in soil gas on the northeastern portion of the parking lot, approximately 30 to 50 feet away from the onsite restaurant building, whereas COPC concentrations are low or non-detectable immediately adjacent to the building. These findings are consistent with the distribution of COPCs in soil and groundwater at the Property. Semi-annual soil gas monitoring near the building has been initiated to confirm that soil gas concentrations near the building remain below levels of concern.



4.4 GROUNDWATER Historical groundwater quality data indicates that only groundwater from monitoring well MW-WAT1-3 has consistently contained detectable concentrations of constituents of concern, including benzene and ethylbenzene. The concentrations of detectable analytes have generally followed an overall decreasing trend. Based on a general decreasing trend of benzene concentrations in groundwater, only long-term monitoring of groundwater is being conducted.

4.5 APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS The Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) requires the selection of a removal action that is protective of human health and the environment. The USEPA policy is that both Federal and State Applicable or Relevant and Appropriate Requirements (ARARs) should be identified and attained to the extent practicable. The three types of ARARs are described below.

Chemical-specific ARARs. Chemical-specific ARARs are usually health or risk-based numerical values or methodologies that are applied to site-specific conditions. These values establish the acceptable amount or concentration of a chemical that may be found in, or discharged to, the environment.

Location-specific ARARs. Location-specific ARARs set restrictions on the concentration of hazardous substances or the conduct of activities solely because they are in specific locations. Some examples of specific locations are floodplains, wetlands, historic places, and sensitive ecosystems.

Action-specific ARARs. Action-specific ARARs are technology or activity based requirements or limitations on actions taken with respect to hazardous wastes. The requirements are prompted by the particular remedial activities that are selected to accomplish a remedy. Action-specific requirements do not in themselves determine the remedial alternative but indicate how a selected alternative must be achieved. Examples of action-specific ARARs are Resource Conservation and Recovery Act (RCRA) regulations for waste treatment, storage, and disposal.

4.6 APPLICABILITY OF ARARS TO THE PROPERTY

ARARs are identified by first determining whether the requirement is applicable, and if so, whether the requirement is both relevant and appropriate. Soil, soil gas, and groundwater are the media of interest identified for the Property. Potential chemical-, location-, and action-specific ARARs are summarized in Table 4-1.

Potential “To-Be-Considered” Criteria

In addition to ARARs, other nonenforceable criteria, policies, or guidance may be used to screen remedial alternatives under 400 Code of Federal Regulations (CFR) 300.430(e)(2)(I). These criteria may include local restrictions such as noise ordinances as well as city or county permits that may be required to conduct specific removal actions such as excavation or discharge to the publicly-owned treatment works (sewer).



Other Federal and State Laws

Other Federal laws were reviewed as potential ARARs but were judged not to contain standards or regulations pertinent to the RAG at the Property. These laws include, but are not limited to, the Toxic Substances Control Act (TSCA), the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), and the National Environmental Policy Act (NEPA).

In addition, laws regulating activities based on specific historical or environmental features do not appear to be potential ARARs at the Property. These laws include, but are not limited to, the NHPA, the Wild and Scenic Rivers Acts, the Fish and Wildlife Coordination Act, the Wilderness Act, and the Coastal Zone Management Act.



5.0 REMEDIAL ALTERNATIVES

The purpose of this section is to identify remedial alternatives directly applicable for the Property, to evaluate relevant information concerning the removal action options, and to recommend a remedial alternative that can effectively mitigate potential risks associated with the impacted soil. Mitigative measures will be implemented to achieve the removal action goals established in Section 4.0. The overall removal action goal is to minimize potential future exposure of humans (Property workers and visitors) to the COCs that may otherwise be available for ingestion, inhalation, or dermal contact.

5.1 CONTAMINANTS OF CONCERN AND MEDIA OF INTEREST

As indicated earlier, the primary COPCs associated with current Property conditions are PAH in soil and benzene in groundwater. The primary or most significant medium of concern at the Property is shallow soil. It is possible that surface, near-surface, and subsurface soil may be excavated by intrusive workers (i.e., utility trench installation) at the Property. Therefore, such workers could be directly exposed to this soil.

Surface water is a medium of interest at the Property. Based on Property conditions, surface water from the Property may flow onto the adjacent streets and ultimately reach the Pacific Ocean. It should be noted, however, that the surface water flow from the Property is minimal since unpaved drainage areas are small and vegetated. Soil gas is also a medium of interest as COPCs including benzene and naphthalene could potentially further volatilize into the soil gas and migrate through the vadose zone and enter the restaurant through cracks in the floor slab or basement walls.

5.2 GENERAL RESPONSE ACTIONS

General response actions were developed based on the RAGs presented in Section 4.0. General response actions are summarized in Tables 5-1A, 5-1B and 5-1C for soil, soil gas and groundwater, respectively. Applicable technology types and process options were then identified for each general response action, as presented in Tables 5-1A, 5-1B and 5-1C. For the purposes of this RAW, the term "technology type" refers to a general category of technologies, such as capping, excavation, and chemical or biological treatment. The term "process option" refers to the material, equipment, or methodology used to implement a technology.

5.2.1 General Response Actions for Soil

Response actions developed for Property soil include: No Action; Institutional Control; Containment; In situ Treatment; and Soil Excavation combined with Onsite or Offsite Treatment or Offsite Disposal.

The case of No Action is where the Property is left in its existing condition without implementing mitigative measures. This case serves as the baseline for which other alternatives can be compared. The Institutional Control case is a scenario where restrictions are established such as deed restriction to limit land use and/or the maintenance of site control measures (e.g., a cap) to minimize or



prevent potential human contact with contaminants. Containment is where natural or engineered barriers are used to minimize the exposure and/or migration of contaminants. In situ Treatment refers to application of various in situ technologies to destroy, remove or immobilize the contaminants by physical, chemical or biological means. Soil Removal consists of excavating and removing impacted soil from the Property. Onsite Treatment involves the onsite biological, chemical, or physical treatment of soil to minimize the toxicity, mobility, and/or volume of contaminants. Offsite Treatment is similar to the onsite treatment scenario, except that it involves the removal of impacted soil from the Property for treatment at an offsite facility. Offsite disposal involves disposal in a permitted offsite facility.

5.2.2 General Response Actions for Soil Gas

Response actions developed for soil gas include: No Action; Institutional Control; Soil Gas Monitoring; and Soil Vapor Extraction and Vapor Treatment.

The case of No Action is where no soil gas remediation or monitoring would be conducted at the Property. This case serves as the baseline for which other alternatives can be compared. The Institutional Control case is a scenario where restrictions are established such as deed restriction to limit land use and/or the maintenance of site control measures (e.g., vapor barrier) to minimize or prevent potential human contact with impacted soil gas. Soil Gas Monitoring includes the routine long-term collection of soil gas samples near the existing building to verify that impacted soil gas does not encroach upon the building foundation. Under this option, no active remediation of the impacted soil gas will be conducted. Soil Vapor Extraction and Vapor Treatment consists of active extraction of soil gas via a network of soil gas extraction wells located throughout the eastern portion of the parking lot, and treatment of vapors before discharge, under a permit.

5.2.3 General Response Actions for Groundwater

Response actions developed for groundwater include: No Action; Monitored Natural Attenuation; Groundwater Extraction and Treatment; Barrier Wall/Encapsulation; In situ Bioremediation; and Removal of Impacted Groundwater during Soil Excavation.

The case of No Action is where no groundwater remediation or monitoring would be conducted at the Property. This case serves as the baseline for which other alternatives can be compared. Monitored Natural Attenuation takes advantage of naturally occurring potential subsurface processes to reduce groundwater impacts to acceptable levels. Under this option, no active remediation of the impacted groundwater would be conducted; however, the groundwater would be monitored. Groundwater Extraction and Treatment is where impacted groundwater would be extracted by pumping from wells and/or a trench recovery system at the Property. The extracted groundwater would be treated before discharge, under a permit. Barrier Wall/Encapsulation refers to the installation of a barrier wall in the subsurface to confine the contaminants by surrounding the entire impacted groundwater zone. In situ Bioremediation consists of injecting nutrients and oxygen into the groundwater to stimulate and enhance breakdown of contaminants through biological activities. Removal of Impacted Groundwater during Soil Excavation involves removing impacted



groundwater through a combination of removal of vadose and saturated soil and pumping of free liquid from the excavation during the removal of impacted soil.

5.3 IDENTIFICATION AND PRELIMINARY SCREENING OF TECHNOLOGIES AND PROCESS OPTIONS

In this preliminary screening step, technologies and process options are screened on the basis of technical and administrative considerations such as implementability, effectiveness, and comparable costs. The preliminary screening takes into consideration information regarding the contaminant type and concentration, as well as characteristics of a site. Current and future land uses are significant factors in selecting the most appropriate remedial measure. Technologies and process options may be discounted or rejected on the basis of one or more of the following issues:

• An option is not practical in consideration of the volume or area of impacted material;

• An option is not feasible or effective due to onsite conditions such as the location, size, surrounding land use, geology, soil, hydrogeology, or contaminant concentrations;

• An option could not be effectively administered;

• An option is not proven to be effective for the type of onsite contaminants or impacted media; and/or

• An option is significantly higher in cost as compared to other technologies.

Based on experience at other MGP sites in California, options which have proven to be ineffective for contaminants or media at a site were eliminated from the screening process. Potentially viable options, along with an indication of whether an option is retained for further evaluation, are presented in Tables 5-1A, 5-1B and 5-1C for soil, soil gas and groundwater, respectively, and are listed below. A summary of the retained technologies and process options are presented in Tables 5-2A, 5-2B and 5-2C, and discussed below in Sections 5.3.1, 5.3.2 and 5.3.3 for soil, soil gas and groundwater, respectively.

5.3.1 Screening of Technologies and Process Options for Soil

No Action

Under this option, a site is left in its existing condition without any site control or removal action. There is no cost associated with this option, and there is no reduction in contaminant concentrations. This option is listed as a baseline comparison.

Institutional Controls

This option involves controlling the type of construction, business, or activities that can take place at the Property. Fencing and deed restrictions are typical examples of institutional controls. Fencing limits access of unauthorized personnel and thus limits the potential for exposure to contaminants.



Deed restrictions effectively reduce the potential for users of the Property to come in contact with the underlying soil by imposing restrictions on the type of activities that can be conducted at the Property. Deed restrictions have been implemented at the Property but may be amended, if necessary, to address a change in conditions due to remediation.

Containment by Capping

Capping is a proven technology where asphalt, soil, vegetation, or concrete is used to seal or contain contaminants in soil. Capping minimizes the distribution of impacted surface soil or dust and prevents the accidental direct contact by humans or animals. Capping also significantly reduces the infiltration of surface water into the impacted soil zone. However, this option does not reduce the volume or toxicity of impacted soil.

Under the capping option, Institutional Controls, including various restrictions on site use and site activities would be recorded on the property deed to prevent site users from disturbing the cap and coming in contact with underlying impacted soil. Routine inspection and monitoring programs are also required under this option. This option is retained for further consideration.

Soil Excavation

Soil removal by excavation is a common practice at sites with relatively shallow impacted soil and can be accomplished by a wide variety of conventional earth-moving equipment. The primary types of equipment that may be suited for excavations work include loaders, excavators, and backhoes. This option could be implemented at portions of the Property and is retained for future consideration.

Onsite Thermal Desorption of Excavated Soil

Thermal desorption involves excavation of impacted soil and induced volatilization of organic wastes in the excavated soil by heating and subsequent destruction or capture of the resulting gaseous emissions. This process is effective and widely used for the treatment of PAH-affected soil. Mobile units are available and permitted by the DTSC for the treatment and recycling of non-hazardous waste. Under this scenario, treated soil can be used as backfill material or incorporated with asphalt or road base material. The limited size of the Property would prohibit the use of an onsite mobile unit. Space would be required for the placement of the desorption unit in addition to an area large enough for a front end loader to maneuver and load soil into the unit and remove treated soil. Stockpiles and/or containers to manage treated and untreated soil would require additional space. Therefore, this option is not considered viable and is not retained for future consideration.

Offsite Thermal Desorption of Excavated Soil

Thermal desorption involves excavation of impacted soil and induced volatilization of organic wastes in the excavated soil by heating and subsequent destruction or capture of the resulting gaseous emissions. This process is effective and widely used for the treatment of PAH-affected soil. Offsite stationary facilities are available and permitted by the DTSC for the treatment and recycling



of non-hazardous waste. Under this scenario, treated soil can be used as backfill material or incorporated with asphalt or road base material. This option is considered viable and is retained for future consideration.

Offsite Disposal of Excavated Soil

Offsite disposal includes excavation of impacted soil and transportation to permitted landfills or recycling facilities for final disposal. There are several facilities in California and neighboring states, which accept wastes similar to those at the Property. This option is considered viable and is retained for future consideration.

5.3.2 Screening of Technologies and Process Options for Soil Gas

No Action

Under this option, no soil gas remediation or monitoring would be conducted. This option serves as a baseline against which other soil gas remedial options can be compared and will be retained. This option offers no reduction in exposure levels and there is no cost involved within this option.


This option involves controlling the type of construction, business, or activities that can take place at the Property. Fencing and deed restrictions are typical examples of institutional controls. Fencing limits access of unauthorized personnel and thus limits the potential for exposure to contaminants. Deed restrictions have been implemented at the Property but may be amended, if necessary, to address a change in conditions due to remediation.

Monitored Natural Attenuation

Natural attenuation takes advantage of naturally occurring potential subsurface processes such as biodegradation, adsorption, and chemical reactions to reduce impacts to acceptable levels. Under this option, no active remediation of the impacted soil gas would be conducted. However, soil gas would be sampled and analyzed periodically to monitor whether there is a decrease in contaminant concentrations due to natural attenuation processes.

MGP-related contaminants in onsite subsurface soil, soil gas and groundwater generally appear to be in equilibrium. Based on 19 years of groundwater monitoring at the Property, contaminant concentrations in groundwater have generally been decreasing. With over 100 years passing since the MGP was shut down, soil gas has not been significantly impacted near the onsite building, whereas soil gas has been impacted to the northeast of the building in the parking lot where impacts to soil and groundwater are co-located. On this basis, it appears unlikely that contaminated soil gas will migrate from the source area (eastern portion of parking lot) to the existing onsite building, and may actually be attenuating over time. Under this option, no active remediation of the impacted soil gas would be conducted. However, soil gas concentrations will be monitored periodically to demonstrate that conditions are stable and offsite impacts are not migrating beneath the onsite building.



Soil gas monitoring near the building is anticipated to be an effective option for verifying that vapor intrusion into indoor air does not occur in the existing restaurant building. Therefore, this option will be retained for further consideration.

Soil Vapor Extraction and Vapor Treatment

Under this option, a soil gas extraction system consisting of a network of soil gas extraction wells would be installed within the impacted area, and soil gas would be extracted and treated prior to discharge, under a permit. Soil gas would be treated using one or more proven technologies, including thermal oxidation and carbon adsorption. Monitoring would be required to assess the effectiveness of the extraction system.

Given that the primary sources of soil gas impact are likely in the eastern portion of the Former MGP in areas east of the Property, onsite soil vapor extraction may further mobilize impacts from offsite areas into the vadose zone on the Property. However, with placement of extraction wells between the existing building and impacted area in the eastern portion of the Property, it would be effective at preventing soil gas containing COPCs at levels of concern from reaching the building. Therefore, this option will be retained for further evaluation.

5.3.3 Screening of Technologies and Process Options for Groundwater

No Action

Under this option, no groundwater remediation or monitoring would be conducted. This option serves as a baseline against which other groundwater remedial options can be compared and will be retained. This option offers no reduction in exposure levels and there is no cost involved within this option.

Monitored Natural Attenuation

Natural attenuation takes advantage of naturally occurring potential subsurface processes such as volatilization, adsorption, chemical reactions, mineral precipitation, and biodegradation to reduce impacts to acceptable levels. Under this option, no active remediation of the impacted groundwater would be conducted. However, groundwater would be sampled and analyzed periodically to monitor whether there is a decrease in contaminant concentrations due to natural attenuation processes. Natural attenuation parameters would be collected to confirm that aquifer conditions favor natural attenuation and that the observed concentrations declines can be attributed to natural attenuation processes.

Monitored Natural Attenuation is anticipated to be an effective option for the reduction of the concentrations of impacted groundwater. Historical groundwater quality data indicates that only groundwater from monitoring well MW-WAT1-3 has consistently contained detectable concentrations of constituents of concern, most notably benzene. The concentrations of detectable COPCs have generally followed an overall decreasing trend. The decrease in benzene concentrations in monitoring well MW-WAT1-3 is consistent with typical observations at sites



where benzene is undergoing natural attenuation. Therefore, this option will be retained for further consideration.

Groundwater Extraction and Treatment

Under this option, impacted groundwater would be extracted by pumping wells and/or a trench recovery system. The extracted groundwater would be treated before discharge, under a permit.

Because the offsite upgradient portion of the Former MGP and associated subsurface impacts is not being remediated and pumping groundwater from the Property may result in the mobilization of offsite impacts onto the Property, groundwater extraction is not considered practical. As such, this option will not be retained for further evaluation.

Barrier Wall/Encapsulation

Under this option, a barrier wall would be installed in the subsurface to confine the contaminants by surrounding the entire impacted groundwater zone. Barrier walls can consist of slurry walls, sheet pile cutoff walls, or grout walls.

Slurry walls can be constructed in several different ways. For example, with the trench method, a trench is excavated and bentonite slurry is placed to the desired depth. In most cases, the slurry wall is solidified either by incorporating excavated material with bentonite, or by adding cement in the slurry.

Sheet pile cutoff walls are constructed by driving interlocking steel piles into the ground. Because of the joints between piles, sheet pile walls typically leak. Leakage can be reduced through newly developed sealing techniques or, in some cases, fine-grained soils will fill the joints. However, there is a concern about the effective ability of sheet pile walls to control contaminant migration.

Grouting walls are another direct way to control the migration of contaminants in groundwater. A grout wall or curtain is constructed by injecting fluids under pressure into the ground. The grouting material expands out from the zone of injection eventually to gel or solidify, thereby reducing the hydraulic conductivity. The distance of grout penetration varies from site to site but can be relatively small requiring closely spaced injection holes (i.e., 4 to 5 feet). In practice, holes are drilled in two or three staggered rows to ensure that a more or less continuous barrier is constructed. Typical grouting fluids include cement, bentonite, or specialty fluids like silicate grouts.

Periodic monitoring would be required to verify that the barrier did not fail over time. Given the relatively large costs associated with constructing a barrier wall, there are not many examples of their use in these types of remedial applications. Moreover, this alternative would require work across multiple developed properties. This option will not be retained for further evaluation.

In situ Bioremediation

This option includes injection of nutrients and dissolved oxygen into the saturated zone to stimulate and enhance breakdown of hydrocarbons through biological activities. Although both oxygen and



nutrients can be injected to enhance biological activities and breakdown of hydrocarbons, oxygen is the limiting factor in aerobic bioremediation. The addition of oxygen can be accomplished by injection of air, hydrogen peroxide or Oxygen Release Compound (ORC). ORC is a commercially available time-release compound which releases oxygen slowly into the saturated zone. Monitoring of the groundwater is needed to assess the degree of enhanced biodegradation.

In situ bioremediation is a proven technology and may be an effective option for reducing contaminant concentrations in groundwater. Therefore, this option will be retained for further consideration.

Removal of Impacted Groundwater During Soil Excavation

Under this option, impacted groundwater would be removed from the impacted areas by pumping fluid from the excavation, created during the removal of impacted soil. The extracted liquids would be stored in an onsite aboveground tank. The stored liquids would be either treated onsite and discharged under a permit or transported to an appropriate offsite facility for treatment and disposal. Treatment and discharge permits would be required for onsite treatment and discharge. Monitored Natural Attenuation would then be conducted until the removal action goals for groundwater are achieved. As groundwater recovery would be minimal under an excavation scenario, this option will not be retained for further evaluation.

5.4 DEVELOPMENT OF ALTERNATIVES

This subsection describes the rationale for combining the options retained from the initial screening process, described in the subsection above, into preliminary remedial alternatives. These alternatives have been developed to meet the previously stated removal action goals. The assembled alternatives are discussed below.

5.4.1 Remedial Alternatives for Soil

Four alternatives (including the No Action Alternative) have been developed by combining compatible and complementary options into removal action scenarios that would address impacted soil at the Property. The objective is to consider options that would adequately protect public health and the environment and which would be technically feasible. The assembled alternatives for soil are discussed below in greater detail.

Soil Alternative No. 1 - No Action

Under this alternative, the Property would be left in its existing condition without the benefits of Property control or cleanup activities. Retention of this alternative is mandated under the National Oil and Hazardous Substances Pollution Contingency Plan (also called National Contingency Plan [NCP]). As indicated earlier, this category merely serves as a baseline for comparison with other alternatives. There are no costs associated with this option.



Soil Alternative No. 2 - Capping with Institutional Control and Focused Excavation with Offsite Disposal

This alternative includes placing and/or maintaining a cap (asphalt, soil, or concrete) over the impacted soil beneath the Property. Portions of the planters that contain elevated CPAH concentrations would be excavated to a depth of 2 feet bgs or to the base of the foundations of adjacent structures (e.g., buildings and retaining walls), whichever is shallower. A permeable synthetic geotextile mesh would be installed at the base of the excavated planters prior to backfilling with clean fill. Larger plants would remain in place while smaller shrubs would be removed from the planters and replaced after backfilling. Paved areas of the Property would then be re-paved with new asphalt or concrete paving. An institutional control in the form of a deed restriction would then be placed on the property to maintain the cap and to prohibit activities that could damage or penetrate the cap. This alternative thereby prevents exposure to Property users, minimizes the distribution of impacted soil or dust, and reduces water infiltration. The volume and concentrations of contaminants would be reduced under this option, although to a lesser extent than in Soil Alternatives Nos. 3 and 4.

Soil Alternative No. 3 - Excavation of Impacted Soil and Offsite Treatment

Under this alternative, impacted soil would be excavated to depths ranging from approximately 2 feet to 20 feet using standard earthmoving equipment. Excavated soils would then be transported to an approved treatment/recycling facility. The excavated area would be backfilled and restored to pre-excavation conditions. The volume and concentrations of contaminants would be reduced under this option.

Soil Alternative No. 4 - Excavation of Impacted Soil and Offsite Disposal

This alternative also includes the excavation of impacted soil, but the soil would be disposed of at an appropriately permitted facility with or without pre-treatment processes. The volume and concentrations of contaminants at the Property would be reduced under this option.

5.4.2 Remedial Alternatives for Soil Gas

Four alternatives (including the No Action Alternative) have been developed by combining compatible and complementary options into removal action scenarios that would address impacted soil gas at the Property. The objective is to consider options that would adequately protect public health and the environment and which would be technically feasible. The assembled alternatives for Property soil gas are discussed below in greater detail.

Soil Gas Alternative No. 1 - No Action

Under this alternative, no soil gas remediation or monitoring will be conducted at the Property. This option serves as a baseline against which other soil gas remedial options can be compared. Retention of the No Action Alternative is required by the NCP. There are no costs associated with this alternative.



Soil Gas Alternative No. 2 – Soil Gas Monitoring with Institutional Control

Under this alternative, no active remediation of the impacted soil gas would be conducted. However, soil gas would be sampled from soil gas probe locations adjacent to the existing building semi-annually and analyzed for VOCs to monitor whether contaminants in soil gas are approaching the building. An institutional control in the form of a deed restriction would then be placed on the property to prohibit the construction of new enclosed building(s) within the area of impact (eastern portion of parking lot).

With over 100 years passing since the MGP was shut down, soil gas has not been significantly impacted near the onsite building, whereas soil gas has been impacted to the northeast of the building in the parking lot where impacts to soil and groundwater are co-located. In the unlikely event that COPCs in soil gas migrate in vadose soil towards the building, the soil gas monitoring near the building would identify contaminated soil gas before it reaches the existing building, so that additional action could be taken as warranted. This alternative thereby prevents Property users from being exposed to impacted soil gas that could result from the intrusion of vapors through the building foundation or basement walls into indoor air.

Soil Gas Alternative No. 3 – Soil Vapor Extraction and Vapor Treatment, Soil Gas Monitoring and Institutional Control

Under this alternative, a series of vapor extraction wells would be installed between the building and the impacted area on the east side of the parking lot. The placement and design of the extraction wells would be completed to optimize the capture of soil gas migrating toward the building from the impacted area. In addition, one or more vapor extraction wells would be installed in the impacted area on the east side of the parking lot to minimize further migration of impacted soil gas towards the building. Soil gas extracted from the wells would be conveyed to an onsite treatment system, and treated using one or more proven technologies, including thermal oxidation and carbon adsorption. Routine operation and maintenance activities will be required. Existing soil gas probes adjacent to the building would be sampled semi-annually, as described in Alternative No. 2, to assess the effectiveness of the extraction system. An institutional control in the form of a deed restriction would then be placed on the property to prohibit the construction of new enclosed building(s) within the area of impact (eastern portion of parking lot), and to prohibit activities that could damage the subsurface vapor collection system.

In the unlikely event that contaminated soil gas migrates in vadose soil towards the building, construction of the vapor extraction system would be effective at intercepting such soil gas. This alternative thereby prevents Property users from being exposed to impacted soil gas that could result from the intrusion of vapors through the building foundation into indoor air.

5.4.3 Remedial Alternatives for Groundwater

The following alternatives (including the No Action Alternative) were retained through the screening process and have been developed by combining compatible and complimentary options into removal action scenarios that would address the groundwater impact at the Property.



The objective is to consider options that would adequately accomplish goals and would be technically feasible. The assembled alternatives are discussed below in greater detail.

Groundwater Alternative No. 1 - No Action

Under this alternative, no groundwater remediation or monitoring will be conducted at the Property. This option serves as a baseline against which other groundwater remedial options can be compared. Retention of the No Action Alternative is required by the NCP. There are no costs associated with this alternative.

Groundwater Alternative No. 2 - Monitored Natural Attenuation

Under this option, no active remediation of the impacted groundwater would be conducted. However, groundwater would be sampled and analyzed for dissolved contaminants and monitored natural attenuation (MNA) parameters to monitor the natural attenuation processes. Natural Attenuation takes advantage of naturally occurring potential subsurface processes such as biodegradation, volatilization, adsorption, chemical reactions, mineral precipitation, and biodegradation to reduce impacts to acceptable levels.

Semi-annual groundwater monitoring has been conducted at the Property since 1997 and has shown a reduction in the concentrations of constituents in groundwater. Therefore, this option will be retained for further consideration as an alternative.

Groundwater Alternative No. 3 - In situ Bioremediation

This option stimulates aerobic degradation of benzene by increasing dissolved oxygen concentrations in groundwater. ORC would be used as the oxygen source and applied by placing filter socks containing ORC into wells at the Property and allowing the socks to remain in the saturated zone of the wells for extended periods of time. Oxygen would be slowly released to groundwater for up to one year following each application of ORC.

In addition to the existing onsite wells, it is anticipated that three additional wells would be drilled and used to deliver ORC to the subsurface. Monitoring of the groundwater is needed to assess the degree of enhanced biodegradation.

In situ bioremediation may be an effective option for reducing contaminant concentrations in impacted groundwater at the Property. Therefore, this option will be retained for further consideration as an alternative.

5.5 REMEDIAL ALTERNATIVE EVALUATION CRITERIA

This RAW is prepared pursuant to Health and Safety Code section 25356.1 as a non-emergency removal action at a hazardous waste site which is projected to cost less than $2 million. As such, response actions will be conducted pursuant to Health and Safety Code Chapter 6.8 in a manner that is consistent with the NCP. For removal actions with a planning period of six months, the NCP requires the use of an Engineering Evaluation and Cost Analysis (EE/CA) or its equivalent. The



USEPA guidance on “Conducting Non-Time Critical Removal Actions Under CERCLA” identifies effectiveness, implementability and cost as the three evaluation criteria for evaluating removal action alternatives. Therefore, these three criteria are considered in the analysis of the alternatives to ensure that the RAW is prepared following the EE/CA or its equivalent.

This section presents an evaluation of the remedial alternatives using the three criteria: effectiveness; implementability; and comparative costs. These are the same criteria that were used for the screening of technologies and process options, except that in this screening process the alternatives are evaluated on the basis of their potential to address remediation of the Property, and not just evaluation of a technology.

Effectiveness

The effectiveness criterion essentially evaluates the ability of an alternative to reduce toxicity, mobility, volume, or exposure to contaminants and its short-term and long-term ability to protect public health and the surrounding environment.

Implementability

Implementability is a measure of the technical and administrative feasibility of constructing, operating, and maintaining a removal action alternative. Implementability is used to evaluate an alternative’s combination of process options with respect to Property conditions. Technical feasibility refers to the ability to construct, reliably operate, and meet technology-specific regulations for process options until removal action is complete. It also includes operation, maintenance, replacement, and monitoring of technical components of an alternative, if required, after the removal action is complete. Administrative feasibility refers to the ability of an alternative to obtain approvals from the regulatory agencies.

Cost

Preliminary cost estimates are developed for each alternative to provide a relative comparison to other alternatives. Initial capital as well as operation and maintenance costs are considered. The cost estimates are based on cost estimating guides, generic unit prices, product/service vendor information, prior experience, and engineering judgment based on professional experience. Preliminary cost estimates developed for the alternatives are presented in Tables 5-3A, 5-3B and 5-3C for soil, soil gas and groundwater, respectively.

5.6 DESCRIPTION AND EVALUATION OF ALTERNATIVES

This section presents a more detailed evaluation of each of the four final alternatives for soil, three final alternatives for soil gas, and three final alternatives for groundwater. The final soil alternatives consist of No Action; Capping with Institutional Control and Focused Excavation with Offsite Disposal; Excavation of Impacted Soil and Offsite Treatment; and Excavation of Impacted Soil and Offsite Disposal. The final soil gas alternatives consist of No Action; Soil Gas Monitoring with Institutional Control; and Soil Vapor Extraction and Vapor Treatment, Soil Gas Monitoring and



Institutional Control. The final groundwater alternatives include No Action, Monitored Natural Attenuation and In situ Bioremediation.

5.6.1 Alternatives for Soil

5.6.1.1 Soil Alternative No. 1 – No Action

Description

As indicated earlier, the No Action alternative serves as a baseline against which the other removal action alternatives can be evaluated. There would be no removal action under the No Action alternative.

Evaluation

Effectiveness. There would be no additional short-term risk posed to the community or the environment because no removal action will be performed under this alternative.

Implementability. The implementability criterion is not applicable for the No Action alternative.

Cost. There are no remedial costs associated with this alternative.

5.6.1.2 Soil Alternative No. 2 – Capping with Institutional Control and Focused Excavation with Offsite Disposal

Description

This alternative includes covering the impacted areas with a surficial cap and/or maintaining an existing cap. The existing parking lot at the Property would be repaved with asphalt or concrete, which will require grading and removal of up to approximately 200 cubic yards of soil. Focused soil excavation (approximately 100 cubic yards) would take place in some of the planters to remove CPAH contaminated soil (Figure 6-1). Small plants would be removed prior to excavation whereas large plants and trees would remain and excavation activities would be conducted, by hand, in the vicinity of these larger plants to remove as much contaminated soil as possible without damaging the plants. A permeable synthetic geotextile mesh would be placed at the bottom of the excavation prior to backfilling with clean fill. The affected planter areas would then be landscaped.

The deed restriction, which already exists for the property, would be amended to address a change in conditions due to remediation. The existing Land Use Covenant is attached as Appendix B. The deed restriction would be amended to prohibit future alteration of the protective caps. A Soil Management Plan for future excavation or disturbance of contaminated soil would be required in addition to periodic inspection of the caps, and maintenance as necessary. Any potential disturbance of the protective caps in the impacted areas in the future would have to be pre-approved by the DTSC.

The proposed deed restriction amendments would also include the following items:



• Construction activities in the impacted soil zones beneath the caps would need to be pre-approved by the DTSC and conducted under a Site-specific Health and Safety Plan (HSP) prepared in accordance with the specifications set forth in California Code of Regulations (CCR), Title 8, Section 5192 (8 CCR 5192) and the Code of Federal Regulations, Title 29, Part 1910.120 (29 CFR 1910.120);

• Any excavated soil would have to be handled properly, profiled for disposal and transported to a suitable facility for treatment/recycling and disposal. The excavations would have to be backfilled with clean, imported fill material and compacted; and

• Upon completion of any construction activities in the impacted soil zones beneath the caps, the caps would have to be appropriately repaired.

Evaluation

Effectiveness. The effectiveness of this alternative is evaluated for both short-term and long-term effectiveness in the following paragraphs.

The primary threat to the community would be from inhalation of dust (and potential odor and organic vapors) during surface grading and initial paving or repaving. This threat could be substantially mitigated by implementation of standard odor and dust suppression measures, which would include wetting of surface soil, covering exposed soil with foam or plastic sheeting during periods of inactivity, and ceasing grading during periods of significant wind speeds. By implementing prudent measures, this alternative would be sufficiently protective of the surrounding community during removal action implementation.

Remediation workers could be exposed to impacted soil during grading and initial paving. The routes of potential exposure would include inhalation, dermal absorption, and ingestion. Appropriate protective equipment, such as Tyvek® coveralls, gloves, and respirators (if needed) would be used by remediation workers that may come in contact with impacted materials. Proper use of protective equipment would substantially reduce exposure risks. Air monitoring would also be conducted throughout construction activities, and water spray and dust control measures detailed above would be implemented. A Site-specific HSP would be developed and implemented to meet the requirements of the California Health and Safety Code, Title 8, and Proposition 65. The HSP would assign responsibilities, establish personnel protection standards and mandatory safety procedures, and specify appropriate measures and procedures to be taken for contingencies that may arise while operations are being conducted at the Property and/or while excavated materials are being transported to the offsite facility. During grading and paving, some dust and odor emissions could be generated at the Property. These emissions are expected to be low and the dispersal radius would be small. Anticipated environmental impact during remediation would be minimal. Unless unexpected difficulties or delays are encountered, capping (where needed) could be completed over a relatively short period.

Caps would prevent direct contact with contaminants by Property users. Because of its protectiveness and the relatively immobile nature of contaminants (e.g., PAHs), this alternative



would effectively eliminate the soil, air, and surface water exposure pathways. However, this alternative would achieve little or no reduction in the volume or toxicity of contaminants. Construction workers would be potentially exposed to the impacted soil during intrusive work. Long-term operation and maintenance controls associated with this alternative would include routine inspection, repair, and maintenance of the caps, and institutional controls. These controls are considered reliable and should provide adequate protection for human health and the environment.

Implementability. Installation/maintenance of caps, where needed, could be completed using well-demonstrated technologies. From a technical standpoint, there should be no difficulties or uncertainties associated with cap construction/maintenance. Administratively, local construction permits would likely be required.

Cost. The total cost of this alternative is estimated to be approximately $520,000 as shown in Table 5-3A. With the exception of small planter areas surrounding the building and at the edge of the parking lot, the entire Property is already covered with a building and asphalt paving. Direct costs would likely consist of Property preparation, construction, and dust control. The costs also include the upkeep and maintenance of the caps. However, indirect costs, such as those for administration, or the administrative cost for DTSC supervision during the remedial activities, are not included in these estimates.

5.6.1.3 Soil Alternative No. 3 - Excavation of Impacted Soil and Offsite Treatment

Description

This alternative includes excavation and offsite treatment (thermal desorption treatment/recycling) of soil in areas impacted with PAH. The soil in the impacted areas would be excavated using conventional earthmoving equipment. It is estimated that approximately 3,000 cubic yards (4,500 tons) of soil would be excavated based to a maximum depth of 15 to 20 feet in the parking lot of the Property. Concrete and/or asphalt, where they exist, would be cut and removed first to allow excavation of the underlying impacted soil. Dust/odor control measures such as soil wetting and/or the use of vapor/odor suppressant foam would be implemented during excavation, as necessary. Air monitoring would be conducted during excavation activities.

A permitted offsite facility would be selected to perform the thermal desorption treatment. The excavated soil would be transported in accordance with a Transportation Plan to the facility for treatment using a stationary treatment system. The offsite treatment system would consist of a soil preprocessing unit, including a vibrating screen and continuous weight feeder; a primary soil processing unit, consisting of a rotating cylindrical dryer operating at temperatures between 300 degrees Fahrenheit (°F) to 1,100°F; an off-gas treatment unit, consisting of an afterburner operating at temperatures of 2,000°F to 3,000°F; an emissions control unit, consisting of a wet quenching/scrubbing unit; and a baghouse. The desorber unit would operate on electricity, natural gas or fuel oil, depending on the type of system selected.



At the thermal desorption facility, stockpiled soil would be delivered by a front-end loader to a vibrating screen, which would separate out oversized materials. The soil would then be transferred to a weight feeder. The feeder would deliver soil at a constant rate (depending on treatment capacity of the desorber unit) to a belt conveyor, which in turn would transfer it to the primary dryer. After a residence time of approximately 20 to 30 minutes, the treated soil would be discharged to a pile, and the soil would then be removed by a front-end loader for stockpiling and ultimate reuse. The water within the quencher/scrubber unit could be recycled, and periodically treated and discharged offsite. The treated soil could be used offsite for general backfill material, asphalt/concrete mix, or roadbase. The treated soil would not be returned to the Property

Evaluation

Effectiveness. The primary threat to the community would be from the potential inhalation of dust and potential odor and organic vapors generated during excavation and loading of the impacted soil, and from the transport of soil offsite on the tires and body of the transportation vehicles. This threat could be substantially mitigated by implementation of odor and dust suppression measures, which would include wetting of surface soil, covering exposed soil with foam or plastic sheeting during periods of inactivity, and ceasing excavation during periods of significant wind activity. Loading all trucks over plastic sheeting or similar measures would minimize the amount of soil being tracked offsite by truck tires. To reduce the exposure of the community to the soil being hauled from the Property, the beds of the trucks would be covered, and truck routes would be established that minimize travel through residential areas. This alternative would thus be sufficiently protective of the surrounding community during removal action implementation.

Remediation workers could be exposed to the impacted soil during excavation and loading operations. The routes of potential exposure would include inhalation, dermal absorption, and ingestion. Appropriate protective equipment, such as Tyvek® coveralls, gloves, and respirators would be used by remediation workers that may come in contact with impacted materials. Proper use of protective equipment should substantially reduce exposure risks. Air monitoring would also be conducted throughout construction activities, and water spray and dust control measures detailed above would be implemented. A Site-specific HSP would be implemented to meet the requirements of the California Health and Safety Code, Title 8, and Proposition 65. The HSP would assign responsibilities, establish personnel protection standards and mandatory safety procedures, and specify appropriate measures and procedures to be taken for contingencies that may arise while operations are being conducted at the Property and/or while excavated materials are being transported to the offsite facility.

During remediation, some dust and odor emissions can be expected due to remedial operations. These emissions are expected to be low and the dispersal radius should be small. Environmental impact during remediation is expected to be minimal. Removing impacted soil from excavations and loading onto trucks is expected to be one of the time limiting factors in this alternative. Excavation, transportation and backfill would be completed over a period of approximately 2 to 3 months.



The implementation of this alternative would result in an acceptable residual risk since the concentration, volume and mobility of contaminants in the impacted soil at the Property would be substantially reduced. This alternative is considered reliable and effective. A deed restriction for remediated areas may not be required if the removal action goals were achieved.

Implementability. Soil removal by excavation is a common practice at sites with relatively shallow impacted soil and can be accomplished by a wide variety of conventional earth-moving equipment. The primary types of equipment most suited for site work include front-end loaders, bulldozers, excavators, and backhoes. This option could be implemented at the Property in accessible areas. However, there are numerous Site-specific constraints at this Property related to this approach that include the following:

• The Property is privately-owned and is the location of a popular restaurant in downtown Watsonville;

• Access to the area behind the restaurant requiring excavation is very limited, with only one approximately 10-foot wide driveway;

• Excavation of the estimated volume of soil in this area would result in substantial potential volumes of dust and odor emissions, in very close proximity to the restaurant and other businesses;

• The estimated volume of required excavation would result in approximately 350 truckloads of excavated and imported soils in and out of the Property;

• Given the limited access and space for construction activities, reasonable excavation production rates would result in a construction presence onsite of up to 3 months or more;

• The restaurant building onsite is listed on the City of Watsonville’s Directory of Historical Resources and is deemed as eligible for listing on the National Register of Historic Places (NRHP). The age and historic nature of the building further complicates any nearby deeper excavations (up to 15 to 20 feet deep) due to the reduction in routine settlement tolerances associated with standard excavation design approaches.

Under this option, excavated soils would be transported to a thermal desorption facility. Thermal desorption is a demonstrated technology for the treatment of soil impacted with petroleum hydrocarbons and PAH. Removal efficiencies from the soil would depend on media parameters such as soil type, extent of contaminant adsorption to soil, compound volatility, and on equipment operation parameters such as operating temperature and residence time. This technology has been successfully used for treatment of soil from several similar former MGP sites. Several permitted offsite treatment facilities are available in the market for conducting the thermal desorption treatment and recycling. At least one, located in southern California (TPS Technologies, Inc.), has demonstrated to have successfully conducted thermal desorption treatment and recycling of treated soil from several other similar MGP sites. No significant administrative problems are foreseen for this alternative.



Cost. The total cost of this alternative is estimated to be approximately $1,872,000 as shown in Table 5-3A. Direct costs would consist of excavation, transportation, treatment, backfill, decontamination and reconstruction. Indirect costs, such as those for administration, inspection, and permitting or the administrative cost for DTSC supervision during the remedial activities, are not included in these estimates.

5.6.1.4 Soil Alternative No. 4 - Excavation of Impacted Soil and Offsite Disposal

Description

This alternative includes excavation and offsite disposal of impacted soil in areas impacted with PAHs. Excavation procedures are as described under Alternative No. 3. The impacted soil would be disposed of at a permitted offsite facility.

Evaluation

Effectiveness. Same as Alternative No. 3.

Implementability. Excavation is the same as Alternative No. 3. Offsite disposal is a demonstrated and acceptable practice for removal of impacted soil from a specific area (e.g., the Property). Several permitted disposal facilities are available. No administration problems are foreseen for this alternative.

Cost. The total cost of this alternative is estimated to be approximately $1,759,500 as shown in Table 5-3A. Direct costs consist of excavation, transportation, disposal, backfill, decontamination, and reconstruction. The cost for additional delineation of impacted area within the building is included. Indirect costs such as those for administration, inspection, and permitting or the administrative cost for DTSC supervision during the remedial activities are not included in these estimates.

5.6.2 Alternatives for Soil Gas

5.6.2.1 Soil Gas Alternative No. 1 – No Action

Description

Under this option, no soil gas remediation or monitoring would be conducted. This option serves as a baseline against which other soil gas remedial options can be compared. This option offers no reduction in exposure levels and there is no cost involved within this option.

Evaluation

Effectiveness. There would be no additional short-term risk posed to the community or the environment because no removal action would be performed under this alternative. In the long-term there would be no reduction in risk posed to the community because no removal action would



be performed under this alternative. However, natural degradation of contaminants in soil gas will likely reduce concentrations from their current levels.



5.6.2.2 Soil Gas Alternative No. 2 – Soil Gas Monitoring with Institutional Control

Description

In the unlikely event that contaminated soil gas migrates in vadose soil towards the onsite building, the soil gas monitoring program would detect the increased soil gas concentrations allowing for additional contingency measures as appropriate. Under this alternative, no active remediation of the impacted soil gas would be conducted. However, soil gas would be sampled at selected existing soil gas probe locations onsite and adjacent to the existing building semi-annually for the first five years and annually thereafter or until the source of the soil gas is permanently mitigated.

A deed restriction, which already exists for the property, would not be removed but would be amended to prohibit the construction of new enclosed building(s) within the area of impact (eastern portion of parking lot) unless appropriate approvals are obtained from DTSC.

Evaluation

Effectiveness. There would be no additional short-term risk posed to the community or the environment because no active removal action would be performed under this alternative. Implementation of this remedial alternative would provide advanced warning if soil gas conditions were to change.

Implementability. No difficulties are anticipated for the construction of soil gas probes (if additional or replacement probes are required) and routine sampling of soil gas under this alternative. Soil gas sampling would be conducted contemporaneously with groundwater sampling, assuming the groundwater sampling activities continue.

Cost. The total cost of this alternative is estimated to be approximately $347,288 as shown in Table 5-3B. Direct costs would consist of soil gas monitoring and sampling, laboratory analyses, and reporting. Indirect costs, such as those for administration, inspection, and permitting or the administrative cost for DTSC supervision, are not included in the estimates. Also, it is assumed that the existing permanent soil gas probes at the Property will be used for long-term monitoring, and that no additional costs for the replacement of probes will be incurred.



5.6.2.3 Soil Gas Alternative No. 3 – Soil Vapor Extraction and Vapor Treatment, Soil Gas Monitoring and Institutional Control

Description

Under this alternative, active remediation of the impacted soil gas would be conducted. Prior to installation of the soil vapor extraction system, a radius-of-influence investigation would be conducted as part of the engineering design at the Property to obtain soil permeability characteristics required for system design. In accordance with the final design vapor extraction wells would be installed at optimal locations between the building and the impacted area on the east side of the parking lot. Based on the results of the radius-of-influence investigation, the placement and design of the extraction wells would be completed to optimize the capture of soil gas migrating toward the building from the impacted area, effectively creating a soil vapor barrier. In addition, one of more vapor extraction wells may be installed in the impacted area on the east side of the parking lot to minimize further migration of impacted soil gas towards the building. Subsurface piping would convey extracted vapors from the vapor extraction wells to an aboveground treatment system likely located along the northeastern property boundary. Limited soil excavated during installation and construction activities would be disposed of at an offsite landfill. A blower at the treatment system would generate sufficient vacuum to convey soil gas from the extraction wells to the treatment system. The soil gas would be treated using one or more proven technologies, including thermal oxidation and carbon adsorption, prior to being discharged. Periodically, the carbon drums would be changed, with the spent drum being sent offsite for recycling or disposal at a permitted facility. Appropriate permits would be required to discharge the treated effluent and periodic system monitoring and sampling will be conducted in accordance with the permits. Routine operation and maintenance activities will be required.

Select soil gas probes onsite would be sampled semi-annually for the first three years and then annually thereafter for as long as the system is operating, or until discontinuation is approved by the DTSC. An institutional control in the form of a deed restriction would then be placed on the property to prohibit the construction of new enclosed building(s) within the area of impact (eastern portion of parking lot), and to prohibit activities that could damage the subsurface vapor collection system.

Evaluation

Effectiveness. There would be very limited short-term risk posed to the community or the environment because soil drilling and excavation associated with the installation of vapor extraction wells and vapor collection system (primarily subsurface piping) is of limited extent and duration. As with soil alternatives involving soil excavation, the primary threat to the community would be from inhalation of dust (and potential odor and organic vapors) during excavation and construction of the vapor collection system. This threat could be substantially mitigated by implementation of standard odor and dust suppression measures, which would include wetting of surface soil, and covering exposed soil with plastic sheeting during periods of inactivity. By implementing prudent measures, this alternative would be sufficiently protective of the surrounding community during vapor extraction system construction.



Remediation workers could be exposed to impacted soil during soil excavation. The routes of potential exposure would include inhalation, dermal absorption, and ingestion. Appropriate protective equipment, such as Tyvek® coveralls, gloves, and respirators (if needed) would be used by remediation workers that may come in contact with impacted materials. Proper use of protective equipment would substantially reduce exposure risks. Air monitoring would also be conducted throughout construction activities, and water spray and dust control measures detailed above would be implemented. A Site-specific HSP would be developed and implemented to meet the requirements of the California Health and Safety Code, Title 8, and Proposition 65. The HSP would assign responsibilities, establish personnel protection standards and mandatory safety procedures, and specify appropriate measures and procedures to be taken for contingencies that may arise while operations are being conducted at the Property and/or while excavated materials are being transported to the offsite disposal facility. During soil excavation, some dust and odor emissions could be generated at the Property. These emissions are expected to be low and the dispersal radius would be small. Anticipated environmental impact during remediation would be minimal. Unless unexpected difficulties or delays are encountered, soil excavation could be completed over a relatively short period.

Construction and operation of the vapor extraction and treatment system should prevent contaminated soil gas from migrating in the future through vadose soil from the impacted area into the existing building. Implementation of soil gas monitoring would also detect increased soil gas concentrations in the vicinity of the building. However, this alternative would achieve little reduction in the overall volume or toxicity of soil gas contaminants because sources remain in offsite areas east of the Property. Long-term operation and maintenance controls associated with this alternative would include periodic soil gas monitoring, routine inspection, repair, maintenance and operation of the vapor extraction and treatment system, and institutional controls (i.e., a deed restriction). These controls are considered reliable and should provide adequate protection for human health and the environment.

Implementability. The design, installation and operation of soil vapor extraction and treatment systems are common practices at some construction and remediation sites. The primary type of construction equipment most suited for this work would include a drilling rig for the installation of extraction wells, and a backhoe or other trenching equipment for the installation of the collection system piping. The treatment system equipment would be stationed within a small fenced area along the northeastern boundary of the Property. This option could be implemented at the Property, although the limited access in the parking lot area would make soil management difficult and the placement of the treatment system would further limit parking for the operating restaurant.

From a technical standpoint, there should be no difficulties or uncertainties associated with the vapor extraction and treatment system construction or maintenance. Offsite disposal of limited excavated soil is a demonstrated and acceptable practice for removal of impacted soil from a specific area (e.g., the Property). Several permitted disposal facilities are available. No difficulties are anticipated for the routine monitoring and sampling of soil gas probes under this alternative. No administration problems are foreseen for this alternative.



Cost. The total cost of this alternative is estimated to be approximately $1,042,569 as shown in Table 5-3B. Direct costs would likely consist of the radius-of-influence investigation, installation of the vapor extraction wells and collection system, construction of the vapor treatment system, dust control, periodic soil gas monitoring and sampling, laboratory analyses, reporting, and operation and maintenance of the treatment system. However, indirect costs, such as those for administration, or the administrative cost for DTSC supervision during the remedial activities, are not included in these estimates.

5.6.3 Alternatives for Groundwater

5.6.3.1 Groundwater Alternative No. 1 – No Action

Description

Under this option, no groundwater remediation or monitoring would be conducted. This option serves as a baseline against which other groundwater remedial options can be compared. This option offers no reduction in exposure levels and there is no cost involved within this option.

Evaluation

Effectiveness. There would be no additional short-term risk posed to the community or the environment because no removal action would be performed under this alternative. In the long-term there would be no reduction in risk posed to the community because no removal action would be performed under this alternative. However, natural degradation of contaminants in groundwater will likely reduce concentrations from their current levels.



5.6.3.2 Groundwater Alternative No. 2 – Monitored Natural Attenuation

Description

Natural attenuation takes advantage of naturally occurring potential subsurface processes such as biodegradation, volatilization, adsorption, chemical reactions, mineral precipitation, and biodegradation to reduce impacts to acceptable levels. Under this option, no active remediation of the impacted groundwater would be conducted. However, groundwater would be sampled and analyzed to monitor the natural attenuation processes.

Evaluation

Effectiveness. There would be no additional short-term risk posed to the community or the environment because no active removal action would be performed under this alternative. Implementation of this remedial alternative would result in a reduction in the toxicity, mobility, and volume of contaminated groundwater over time.



Implementability. No difficulties are anticipated for the routine monitoring and sampling of groundwater under this alternative. Additional natural attenuation parameters can easily be collected during routine groundwater monitoring events.

Cost. The total cost of this alternative is estimated to be approximately $413,438 as shown in Table 5-3C. Direct costs would consist of groundwater monitoring and sampling, laboratory analyses, water disposal, and reporting. Indirect costs, such as those for administration, inspection, and permitting or the administrative cost for DTSC supervision, are not included in the estimates.

5.6.3.3 Groundwater Alternative No. 3 – In situ Bioremediation

Description

This option stimulates aerobic degradation of benzene by increasing the concentration of dissolved oxygen in groundwater. ORC would be used as the oxygen source and applied by placing filter socks containing ORC into wells at the Property and allowing the socks to remain in the saturated zone of the wells for extended periods of time. Oxygen would be slowly released to groundwater for up to one year following each application of ORC. In addition to the existing onsite wells, it is anticipated that three additional wells would be drilled and used to deliver ORC to groundwater. Monitoring of the groundwater is needed to assess the degree of enhanced biodegradation.

Evaluation

Effectiveness. There would be a small increase in the short-term risk posed to the community or the environment due the drilling and installation of new oxygen delivery wells. Implementation of this remedial alternative would result in a reduction in the toxicity, mobility, and volume of contaminated groundwater over time.

Implementability. Regulatory approval may be required to place ORC in the saturated zone of the oxygen delivery wells. Additionally, the radius of influence of the oxygen delivery wells may be limited due to the presence of low permeability sediments at the Property.

Cost. The total cost of this alternative is estimated to be approximately $552,063 as shown in Table 5-3C. Direct costs would consist of drilling of new oxygen delivery wells, ORC, additional groundwater monitoring and sampling, laboratory analyses, and reporting. Indirect costs, such as those for administration, inspection, and permitting or the administrative cost for DTSC supervision, are not included in the estimates.

5.7 FINAL EVALUATION OF ALTERNATIVES

Four alternatives for soil, three alternatives for soil gas and three alternatives for groundwater have been evaluated in the previous section. Each of these alternatives, except the No Action alternative, would adequately remediate the Property and provide for protection of human health and the environment.



The alternatives were compared with respect to effectiveness, implementability, and cost. Evaluations of the final alternatives for soil, soil gas and groundwater are summarized in Tables 5-4A, 5-4B and 5-4C, respectively.

5.7.1 Comparison of Final Soil Alternatives

Effectiveness

Short-term effectiveness is defined as the ability of each alternative to protect human health and the environment during construction and removal action implementation. Alternative No. 2 (Capping with Institutional Control and Focused Excavation with Offsite Disposal) has better short-term protection than Alternative Nos. 3 and 4, since minimal disturbance of soil occurs as a result of its implementation. Alternative No. 3 (Excavation of Impacted Soil and Offsite Treatment) and Alternative No. 4 (Excavation of Impacted Soil and Offsite Disposal) require extensive excavation and handling of impacted soil and materials. The No Action alternative (Alternative No. 1) would be the least effective.

Long-term effectiveness is defined as the ability of each alternative to protect human health and the environment by reducing the toxicity, volume, and mobility of contaminants. Alternative No. 2 (Capping with Institutional Control and Focused Excavation with Offsite Disposal) provides long-term protection by reducing the mobility of contaminants, but does not offer a material reduction in the toxicity or volume of contaminants. Excavation of Impacted Soil and Offsite Treatment of PAH-impacted soil (Alternative No. 3) would provide a better overall long-term protection, because implementation of this alternative would permanently reduce the toxicity, volume, and mobility of PAH in the soil. Alternative No. 4 (Excavation of Impacted Soil and Offsite Disposal) would be less protective than Alternative No. 3 for PAH-impacted soil, since it would not permanently reduce the toxicity and volume of PAH. The No Action alternative (Alternative No. 1) would be the least effective.

Implementability

Each of the final alternatives, except the No Action alternative, utilizes well demonstrated and reliable technologies. Alternative No. 2 (Capping with Institutional Control and Focused Excavation with Offsite Disposal) can be readily implemented and has demonstrated success at a number of former MGP sites, as MGP residues are generally not appreciably mobile in the subsurface environment. Alternative No. 3 (Excavation of Impacted Soil and Offsite Treatment) and Alternative No. 4 (Excavation of Impacted Soil and Offsite Disposal) could be implemented as well, but with great difficulty due to adjacent structural improvements (buildings and retaining walls), limited access, and use of the Property as a restaurant.

Cost

The alternatives, listed in order of increasing present worth cost, are as follows: Alternative No. 1 (No Action), Alternative No. 2 (Capping with Institutional Control and Focused Excavation with Offsite Disposal), Alternative No. 4 (Excavation of Impacted Soil and Offsite Disposal), and Alternative No. 3 ( Excavation of Impacted Soil and Offsite Treatment).



5.7.2 Selection of the Final Soil Alternative

Alternative No. 2 (Capping with Institutional Control and Focused Excavation with Offsite Disposal), Alternative No. 3 (Excavation of Impacted Soil and Offsite Treatment), and Alternative No. 4 (Excavation of Impacted Soil and Offsite Disposal) would all adequately remediate the Property and provide for the protection of human health and the environment. Alternative No. 1 (No Action) is not protective of human health and the environment and is therefore eliminated from further evaluation.

Alternative No. 2 (Capping with Institutional Control and Focused Excavation with Offsite Disposal) would have the best short-term effectiveness and would be the easiest to implement. Alternative No. 3 (Excavation of Impacted Soil and Offsite Treatment) would have the highest degree of long-term effectiveness but would be as difficult to implement as Alternative No. 4 (Excavation of Impacted Soil and Offsite Disposal), based on the following key factors:

• The Property is a privately-owned historic building and is the location of a popular restaurant in downtown Watsonville;

• Access to the area behind the restaurant requiring excavation is limited;

• Excavation would result in dust and odor emissions in proximity to the restaurant;

• Approximately 350 truckloads of excavated and imported soils would enter and exit the Property; and

• Estimated excavation production rates would result in a construction presence onsite of up to 3 months or more.

Alternative No. 2 would also be the most cost effective option, will be in compliance with ARARs and should be acceptable to regulatory agencies.

As outlined above, Alternative No. 2 (Capping with Institutional Control and Focused Excavation with Offsite Disposal) has several advantages over Alternative Nos. 3 and 4. Accordingly, Alternative No. 2 has been selected as the remedial alternative for soil.

Soil Alternative No. 2 has been selected because source removal is limited by several conditions including the year-round presence of an on-site business, access restrictions, space limitations, and the presence of contaminants upgradient of the Site. However, PG&E will reevaluate implementing further remedial actions if future conditions change such that additional source removal is feasible and if access is provided by the property owner.



5.7.3 Comparison of Final Soil Gas Alternatives

Effectiveness

Short-term effectiveness is again defined as the ability of each alternative to protect human health and the environment during construction and removal action implementation. Alternative No. 2 (Soil Gas Monitoring with Institutional Control) has better short-term protection than Alternative No. 3, since minimal disturbance of soil occurs as a result of its implementation. Alternative No. 3 (Soil Vapor Extraction and Vapor Treatment, Soil Gas Monitoring and Institutional Controls) requires some soil drilling, excavation and handling of potentially impacted soil and materials. The No Action alternative (Alternative No. 1) would be the least effective.

Long-term effectiveness is again defined as the ability of each alternative to protect human health and the environment by reducing the toxicity, volume, and mobility of contaminants. Alternative Nos. 1 and 2 offer similar long-term protection of the environment, as there should be a reduction in the toxicity, mobility or volume of contaminants under either scenario, as natural biodegradation reduces the toxicity, mobility, and volume of contaminants. However, Alternative No. 2 includes monitoring to verify that impacted soil gas is not approaching the foundation or basement of the existing building and is therefore considered more effective than Alternative No. 1 for the protection of human health from potential vapor intrusion into indoor air, if it were to occur. Alternative No. 3 offers better long-term effectiveness than Alternative No. 2 since the vapor extraction and treatment would minimize migration of contaminated soil gas beneath the existing building, if it were to be detected, and could even reduce the volume of potential impacted soil gas between the building and the vapor extractions wells. However, given that the primary source of the soil gas impact is likely in offsite areas east of the Property, Alternative No. 3 would only act as a soil vapor barrier.

Implementability

Each of the final alternatives, except the No Action alternative, utilizes well demonstrated and reliable technologies. Alternative No. 2 (Soil Gas Monitoring with Institutional Control) can be readily implemented and has demonstrated success in monitoring the presence of impacted soil gas at a number of former MGP sites. Alternative No. 3 (Soil Vapor Extraction and Vapor Treatment, Soil Gas Monitoring and Institutional Controls) could be implemented as well, but with somewhat greater difficulty due to limited access and use of the Property as a restaurant.

Cost

The alternatives, listed in order of increasing present worth cost, are as follows: Alternative No. 1 (No Action), Alternative No. 2 (Soil Gas Monitoring with Institutional Control), and Alternative No. 3 (Soil Vapor Extraction and Vapor Treatment, Soil Gas Monitoring and Institutional Controls).



5.7.4 Selection of the Final Soil Gas Alternative

Alternative No. 2 (Soil Gas Monitoring with Institutional Control) and Alternative No. 3 (Soil Vapor Extraction and Vapor Treatment, Soil Gas Monitoring and Institutional Controls) would each adequately provide for the protection of human health by minimizing the potential for vapor intrusion of contaminated soil gas into indoor air. Alternative No. 1 (No Action) is not protective of human health and the environment and is therefore eliminated from further evaluation.

Alternative No. 2 (Soil Gas Monitoring with Institutional Control) would have the best short-term effectiveness and would be the easiest to implement. Alternative No. 3 (Soil Vapor Extraction and Vapor Treatment, Soil Gas Monitoring and Institutional Controls) would have the highest degree of long-term effectiveness but would be more difficult to implement due to the limited access and use of the Property as a restaurant and may jeopardize the existing subsurface equilibrium by pulling soil vapors from offsite sources and facilitating migration of vapors towards the onsite building.

Alternative No. 2 would also be the most cost effective option, will be in compliance with ARARs and should be acceptable to regulatory agencies.

As outlined above, Alternative No. 2 (Soil Gas Monitoring with Institutional Control) has several advantages over Alternative No. 3. Accordingly, Alternative No. 2 has been selected as the remedial alternative for soil gas.

Trend analyses will be performed on each soil gas probe sample on an annual basis. In the unlikely event that an increasing concentration trend is observed at these locations then additional contingency measures will be implemented as necessary. As part of the engineering design, appropriate thresholds will be established for additional contingency actions.

Soil Gas Alternative No. 3 (Soil Vapor Extraction and Vapor Treatment, Soil Gas Monitoring and Institutional Controls) will be retained as a contingency alternative for soil gas and will be established as a contingency action as part of the remedy design. This option, applied as a contingency measure, includes the installation of a network of vapor extraction wells and collection and treatment system that would be connected to a vapor extraction system should contingency thresholds be exceeded during routine monitoring as part of the implementation of Alternative No. 2.

5.7.5 Comparison of Final Groundwater Alternatives

Effectiveness

Short-term effectiveness is again defined as the ability of each alternative to protect human health and the environment during construction and removal action implementation. Of the three final viable alternatives, Alternative No. 1 (No Action) and Alternative No. 2 (Monitored Natural Attenuation) have better short-term protection than Alternative No. 3 (In situ Bioremediation) since Alternative No. 3 requires drilling of new wells and placement of ORC in existing and new wells at the Property. However, the short-term impacts of Alternative No. 3 can be minimized and controlled to provide adequate protection of human health and the environment.



Long-term effectiveness is defined as the ability of each alternative to protect human health and the environment by reducing the toxicity, volume, and mobility of contaminants. Alternative Nos. 1 and 2 offer similar long-term protection of the environment, as there should be a reduction in the toxicity, mobility or volume of contaminants under either scenario, as natural biodegradation reduces the toxicity, mobility, and volume of contaminants. However, Alternative No. 2 includes monitoring to verify that natural degradation processes are reducing contaminant concentrations and is therefore considered more effective than Alternative No. 1. Alternative No. 3 offers better long-term effectiveness than Alternative No. 2 since the degradation of contaminants would occur more rapidly under this alternative.

Implementability

Alternative No. 2 would be modestly more difficult to implement than Alternative No. 1, but is a demonstrated and reliable approach. There would be no foreseeable administrative difficulties for either Alternative Nos. 1 or 2. Alternative No. 3 would be more difficult to implement than the other Alternatives due to the need to drill new wells, apply ORC periodically, and monitor existing and new wells.

Cost

The groundwater alternatives, listed in order of increasing present worth cost, are as follows: Alternative No. 1 (No Action), Alternative No. 2 (Monitored Natural Attenuation), and Alternative No. 3 (In situ Bioremediation).

5.7.6 Selection of Final Groundwater Alternative

As outlined above, Alternative No. 2 (Monitored Natural Attenuation) has several advantages and meets all applicable requirements. The alternative is readily implementable, effective at reducing toxicity, mobility, and volume of contaminated groundwater, and has a moderate cost relative to the other alternatives. Therefore, Alternative No. 2 is selected as the remedial alternative for groundwater.

The concentrations of detectable analytes have generally followed an overall decreasing trend. Benzene concentrations in monitoring well MW-WAT1-3 have decreased from a high of 140 micrograms per liter (µg/L) in June 1991 to as low as 0.53 µg/L in October 2009. Although seasonal fluctuation in concentrations appear to be associated with the fluctuation in the groundwater table, these decreases in dissolved concentrations support the supposition that natural degradation is occurring at the Property. Continued groundwater monitoring with the addition of monitoring for natural attenuation parameters will ensure that concentration trends continue to decrease.

Groundwater Alternative No. 3 (In situ Bioremediation) will be retained for use as a contingency to Alternative No. 2. This option will be applied as a contingency measure if it is determined that a sustained increasing trend in contaminant concentrations in groundwater is observed over three or more groundwater sampling events, directly attributable to MGP-related sources originating from the Property. Contingency actions will include introduction of ORC into wells at the Property.



Oxygen would be slowly released to groundwater for up to one year following each application of ORC. Since groundwater impacts are expected to be present immediately upgradient (off-site) of the Property, several factors would be reviewed and evaluated to determine the validity of adopting this or any other contingency measure, in the unlikely event that the trend of concentrations in groundwater are shown to be increasing. At a minimum, establishment of this contingency action would be conditional on: (1) the data showing that impacted groundwater from upgradient off-site sources are not responsible for increases in concentrations in groundwater beneath the Property, and (2) increasing trends are evident in groundwater concentrations at downgradient wells at the boundary of the Property.



6.0 REMOVAL ACTION IMPLEMENTATION

6.1 SUMMARY OF SELECTED REMEDIAL APPROACH The selected remedial approach for soil consists of containment and institutional controls along with focused excavation of soil to minimize potential future exposure of humans (Property workers and visitors) to CPAH that might otherwise be available for ingestion, inhalation, or dermal contact. This approach will include the removal of near-surface soil within landscape planter areas that contain elevated CPAH concentrations and backfilling with clean import soil. The approach will also include replacement of all existing asphalt pavement and the surface water drainage system. The new pavement and clean soil backfill within the planters will collectively constitute a cap to contain or conceal the underlying impacted soil. Once the cap is installed, an operation and maintenance (O&M) plan will be developed to ensure that the cap is properly maintained and functioning as intended. The existing deed restriction (institutional control) will provide a mechanism to further reduce potential exposure to Property users as a result of potential periodic subsurface repair work.

The selected remedial approach for soil gas consists of Soil Gas Monitoring. This approach will include continuation of the semi-annual soil gas monitoring program that began in October 2009. The nature of soil gas sampling is described in Section 7.0.

The selected remedial approach for groundwater consists of Monitored Natural Attenuation. This approach will include continuation of the existing semi-annual groundwater monitoring program that began in 1997. The nature of Natural Attenuation Monitoring is described in Section 7.0.

The existing deed restriction (institutional control) will be modified to provide a mechanism to further reduce potential exposure to Property users by preventing the construction of building(s) over the impacted area (eastern portion of parking lot).

6.2 QUALITY ASSURANCE/QUALITY CONTROL (QA/QC) PLAN A Quality Assurance/ Quality Control (QA/QC) Plan is necessary to assure that all environmental data obtained will be scientifically valid, defensible, of known quality and that reports are correct and accurate. A detailed QA/QC Plan has been written for this RAW and is included as Appendix C. The QA/QC Plan specifies QA/QC procedures, collection of QA/QC samples, sample handing, QA/QC audits and correction actions, QA/QC for review of documents, QA objectives for measurement data, definition of criteria, and goals for assessment criteria.

6.3 SOIL REMEDIATION OVERVIEW 6.3.1 Demolition

Existing features to be demolished will include all asphalt pavement within the Property boundaries, the existing surface water drainage system, as well as relatively small plants and shrubs within portions of the planters that are in exposed areas impacted with CPAH. Remaining features, including building structures and larger shrubs and trees, will be protected in-place unless field



conditions dictate otherwise. Any unknown subsurface features encountered during soil remediation activities will be addressed on a case-by-case basis.

Groundwater monitoring wells MW-WAT1-1 through MW-WAT1-7 will be protected in-place during remediation. However, the well boxes for monitoring wells MW-WAT1-1 through MW-WAT1-4, and MW-WAT1-6 and MW-WAT1-7 may need to be replaced during the reconstruction and repaving of the parking lot.

6.3.2 Soil Removal

Soil will be removed only from portions of the planters that contain elevated CPAH concentrations. Impacted soil will be excavated to a depth of 2 feet bgs or to the base of the foundations of adjacent structures (e.g., buildings and retaining walls), whichever is shallower. The areas targeted for soil removal are depicted on Figure 6-1. Soil samples will be collected from the base of the excavated areas to further document the residual CPAH concentrations. Prior to backfilling, the floor of the excavations will be covered with a synthetic geotextile mesh to provide an obvious transition point between clean and CPAH-affected soil and to deter future excavation into the underlying impacted soil. The excavations will be backfilled with clean, imported fill material, and the Property will be restored. The soil remediation will be conducted in accordance with the following general sequence:

1. Surface paving will be sawcut and removed, if necessary.

2. Impacted soil will be removed using a small backhoe in planter areas that are easily accessible, and manually using a shovel in areas adjacent to large trees to ensure that the greatest amount of soil can be removed without significantly disturbing the trees.

3. Excavated soil will be loaded into trucks or roll-off bins with a skip loader, and transported offsite for disposal.

4. Clean soil will be used to backfill the excavations.

5. Following backfilling, new asphalt paving will be placed and planters will be reconstructed to match existing conditions.

6.3.3 Pavement Improvement

After soil remediation is completed and the excavated areas have been backfilled, the entire parking lot will be repaved with approximately 4 inches of asphalt or concrete. The existing storm drain system will be replaced to eliminate the ponding of surface water within the parking lot. The new paving will be underlain by approximately 4 inches of Class II aggregate base material (Class II AB) that will be placed under the direction of a Soil Engineer, and in accordance with a City of Watsonville grading permit. Monitoring wells MW-WAT1-1 through MW-WAT1-4 and MW-WAT1-6 and MW-WAT1-7 will be provided with new traffic-rated well boxes to accommodate relative differences of the finished surface.



6.4 PROPERTY SECURITY AND ACCESS During work activity periods, the Property will be secured to provide for the protection and safety of restaurant workers, patrons, onsite construction personnel and equipment and to prevent unauthorized access. A 6-feet high, chain-link fence, with a visual barrier (tarpaulin-like mesh) will be set up around the excavation area. The fenced area will include the exclusion, decontamination, and support zones, as well as the staging area. During non-working hours, the fencing will be fully closed and locked. During remedial activities, Property access will be restricted to authorized personnel only.

6.5 TRAFFIC CONTROL Traffic control measures associated with Property work will be implemented on Main Street, as required by Caltrans and the city of Watsonville. The shoulder lane along northbound Main Street may be temporarily closed, if necessary, under an encroachment permit issued by the City of Watsonville. Pedestrian traffic may be restricted in accordance with the City of Watsonville guidelines, as necessary. Extreme caution will be exercised during entering and exiting of the work area to ensure safe and uninterrupted traffic flow. Entrance into and departure from the work area by trucks will be facilitated by flag-persons and signage.

6.6 PERMIT REQUIREMENTS All necessary permits for removal activities will be obtained prior to the initiation of remediation. The permits will be kept onsite and be made available for inspection during working hours. The anticipated permits may include, but are not necessarily limited to, the following:

• City of Watsonville Grading or Building Permit;

• City of Watsonville Transportation Permit for waste hauling;

• City of Watsonville Stormwater Discharge Permit for surface water drainage;

• Caltrans and/or City of Watsonville Encroachment Permit to use the sidewalk and roadway shoulder along Main Street for a staging area; and

• All appropriate Monterey Bay Unified Air Pollution Control District (MBUAPCD) air emission rules for visible emissions (Rule 400), nuisance (Rule 402), and particulate matter (Rule 403).

6.7 AGENCY NOTIFICATION At least one week prior to the beginning of intrusive activities, appropriate notifications will be made to DTSC and the County of Santa Cruz Environmental Health Service.



6.8 SOIL REMEDIATION

6.8.1 Preliminary Activities

Preliminary work will consist of all tasks associated with preparing for removal action. The general sequence of preliminary work is outlined below.

• All applicable and necessary permits will be secured;

• Underground Service Alert, commonly referred to as USA or Dig Alert, will be contacted to identify all proximal underground utilities. Each utility will be conspicuously marked and relocated, if necessary;

• Necessary equipment and supplies will be mobilized;

• Temporary facilities and utilities, such as portable toilets and hand-washing stations, will be installed as needed;

• The fencing around the work area will be covered with a visual barrier;

• Work zones, including the exclusion, decontamination, and support zones, will be identified and clearly delineated. The exclusion zone will include all areas of excavation, impacted soil staging, and truck loading. The decontamination zone will be positioned immediately adjacent to the exclusion zone for the purposes of decontaminating personnel, equipment, and vehicles as they exit the exclusion zone. The support zone will be located within the designated work area, but beyond the limits of the exclusion and decontamination zones. The support zone will be used to temporarily store equipment, vehicles, and clean soil;

• The impacted soil staging area will be identified and clearly marked. In order to minimize impacts to the restaurant operations, the soil staging area will be located in the most northern corner of the property. This locations will minimize the impact to the restaurant business, provides the greatest access for trucks and loading equipment, and is centrally located to the areas where soil will be excavated (Figure 6-1). Soil staging for contaminated soil will consist of an area where either a roll-off bin or truck will be placed and loaded with contaminated soil. Once impacted soil has been excavated from all proposed locations, clean fill material will be brought in and stockpiled in the same area where contaminated soil was staged. The clean soil will be placed on a tarp and berms will be set up to prevent runoff from the soil pile; and

• All health and safety equipment and supplies will be positioned for use when needed.



6.8.2 Soil Removal Activities

6.8.2.1 Equipment

Based on space limitations, and sensitivity toward the environmental controls (noise and dust), relatively small equipment will be selected. This equipment may include the following (or equivalent):

Excavation/Loading Equipment

• Small Backhoe. This equipment should produce a noise level of less than 80 decibels (dBA) at the source.

• One Bobcat Loader. This equipment may be used to excavate and load soil and should produce a similar or lower noise level as that of the backhoe.

• One Smooth-Drum Roller. This equipment will be used for compaction of soil to meet Class II AB specifications. This equipment should produce a similar noise level as the other equipment.

Transportation Equipment

A backhoe or loader will be used to load excavated soil into trucks or roll-off bins. Two types of transportation vehicles are considered for transferring wastes to an appropriate destination, roll-off bins or transfer trucks.

Roll-off bins will be used for portions of the excavation where loading processes are relatively slow. Transfer trucks will be used when loading can be achieved within a short period of time. The noise levels associated with these operations are mainly related to the truck's engine or when the roll-off bins are loaded. In either case, the noise will occur over a short duration at intermittent periods.

Other Miscellaneous Equipment

Other small support equipment may also be used during soil remediation. The sizes will be small and the duration of use should be short and intermittent. This equipment may include:

• Saw cutting equipment to cut asphalt. This machine may be used as part of preparation activities at the beginning of each stage. It is anticipated that this machine will be used for a short duration.

• Other equipment may be used on an as-needed basis. Selection of this equipment will be made based on their noise levels, mobility, etc. These equipment pieces may include jack hammers or handheld compactors for areas where equipment access is limited.



6.8.2.2 Excavation Procedures Prior to remediation, the following procedures will be implemented:

• Prioritize area to be excavated first to ensure that access and egress are available for other activities;

• Develop staging and access paths for equipment to be used during remediation, such that offsite tracking of wastes is prevented;

• Develop loading procedures;

• Develop dust control procedures; and

• Locating perimeter air and noise monitoring stations.

6.8.2.3 Backfill and Compaction

Following excavation and soil sampling, the floor of the excavation will be lined with a synthetic geotextile mesh and then backfilled with imported fill material. To ensure that the imported fill is free of contamination, representative samples will be collected and analyzed in accordance with the DTSC’s fact sheet entitled “Information Advisory, Clean Imported Fill Material” (DTSC, 2001).

The proposed backfill material will consist primarily of clean, granular soil that will support vegetation in the planters. Compaction of soil in the planters will not be performed.

6.9 RESTORATION Restoration activities will include the replacement of the surface water drainage system, the replacement of asphalt pavement, and the replanting of plants and shrubbery to match existing conditions. The surface water drainage system includes a series of inlet grates that are interconnected by buried, corrugated metal piping (CMP), which discharges surface water into the gutter along Main Street. This system will be upgraded to provide positive surface water flow from the parking lot to the street.

The pavement section will be constructed in accordance with the Soil Engineer’s recommendations and the City of Watsonville’s requirements. It is currently estimated that the pavement section will consist of 4 inches of asphalt or concrete over 4 inches of Class II AB.

All landscaping will be restored to mirror pre-construction conditions.

6.10 WASTE HANDLING 6.10.1 Types of Wastes

It is anticipated that four types of wastes will be generated, including:



• Recyclable construction debris such as asphalt rubble. The recyclable construction debris will be transported to a local recycling facility via dump trucks;

• Non-recyclable construction debris including landscape vegetation and trash. The non-recyclable construction debris will be transported and disposed at a local landfill via dump trucks;

• Soil impacted primarily with PAH will be transported to the Forward Landfill in Manteca, California. The landfill accepts Class I, II, and III wastes and therefore will be suitable for the anticipated (Class II) waste excavated at the Property; and

• Water generated as a result of decontaminating sampling tools or equipment will be temporarily containerized and subsequently disposed of at an appropriate offsite facility.

6.10.2 Transportation Plan

Soil impacted primarily with PAH and petroleum compounds will be transported to the Forward Landfill in Manteca, California. All transportation activities will be performed in strict compliance with all regulations and ordinances. The selected transportation company will be appropriately licensed and certified. The hauling contractor(s) used to transport impacted waste will be fully licensed and permitted by the USEPA and the State of California. All Department of Transportation (DOT) and California Highway Patrol (CHP) safety regulations will be strictly followed.

Transportation equipment will be chosen to safely transport the expected volumes of soil, taking into consideration the types of roads to be traveled and their loading capacity. Routine truck maintenance and repairs will be performed at the contractor’s premises prior to picking up loads of waste material from the Property. The contractor will be required to cleanup, to the satisfaction of the regulatory agencies involved, any spills resulting from maintenance of the trucks or due to road accidents during the operation of this project.

Trucks will use only pre-planned and authorized routes, as approved by the City of Watsonville. The anticipated route from the Property to the Forward Landfill is as follows:



Start out going NORTHWEST (turn RIGHT) on MAIN ST./CA-152. 0.1 miles

Veer LEFT, staying on MAIN ST./CA-152. Continue to follow MAIN ST. 1.6 miles

Merge onto CA-1 NORTH toward SANTA CRUZ. 14.2 miles

Merge onto CA-17 NORTH toward SAN JOSE / OAKLAND. 26.5 miles

Merge onto I-880 NORTH. 12.5 miles

Merge onto MISSION BLVD / CA-262 EAST toward I-680 / SACRAMENTO. 1.2 miles

Merge onto I-680 NORTH toward SACRAMENTO. 17.0 miles

Merge onto I-580 EAST toward STOCKTON. 20.0 miles

Take I-205 EAST toward TRACY / STOCKTON. 14.5 miles

Merge onto I-5 NORTH. 5.9 miles

Take the ROTH ROAD exit toward SHARPE DEPOT. 0.2 miles

Turn RIGHT onto ROTH RD. 1.4 miles

Turn LEFT onto SOUTH AIRPORT WAY / CR-J3. 1.2 miles

Turn RIGHT onto FRENCH CAMP RD / CR-J9. 4.1 miles

Turn LEFT onto SOUTH AUSTIN RD. 2.0 miles

Arrive at 9999 South Austin Rd, Manteca, CA 95336-8924

A detailed log of the loads hauled from the Property will be maintained. The log will include, at a minimum, the date and the time trucks were loaded and off-loaded, the destination, size (volume and weight) of the load, description of contents, name and signature of the hauler, and name and signature of the contractor’s representative. The waste will be off-loaded for treatment or disposal in a manner consistent with current Federal USEPA, State, and local regulations.

Trucks used for the offsite transportation of impacted soil and debris will remain on clean areas at all times to minimize the need to decontaminate the truck tires. During loading, dust and odor emissions will be monitored and mitigated as necessary. The hauling trucks will be equipped to fully cover all soil and debris during transportation. At a minimum, the impacted soil and debris will be tightly covered by a heavy tarpaulin.

6.11 SPILL RESPONSE PLAN In the unlikely event of an inadvertent spill, the remediation contractor will be responsible and will be prepared to respond in a safe and efficient manner, specific to the particular spill situation. Standards will be set and consistent procedures will be used for handling of spills, whether they are onsite spills or spills occurring during transportation. The HSP will address the handling of onsite spills. Because safety and protection of the public and the environment are of major concern, the



first consideration is that of public safety and environmental protection. An Emergency Spill Contingency Plan (ESCP) will be prepared to ensure that all drivers and dispatchers know their responsibilities in the unlikely event that an accident occurs during loading or while transporting impacted material. The drivers, dispatchers, managers, and emergency response personnel will be required to know the procedures for emergency spill response. The ESCP will be prepared to meet or exceed all Federal, State, and County regulations currently in effect. The provisions of the ESCP will be strictly adhered to, in order to ensure continued protection of the public safety and the environment.

6.12 ENVIRONMENTAL CONTROL 6.12.1 Noise

To reduce the noise level during remediation, the following factors were incorporated:

• Equipment operation will be limited to daylight hours, Monday through Friday.

• In general, the excavation equipment to be used at the Property will not be exceedingly large and they will be properly and routinely maintained such that their noise levels will be relatively low.

A noise-level meter will be used to monitor the perimeter of the remediation area to minimize the affect of remediation on surrounding properties. The City of Watsonville standards for construction noise limits require that any single piece of equipment not exceed 85 dBA at a distance of 50 feet while operating at its noisiest mode. If noise monitoring data indicate that sustained levels exceed 85 dBA at the perimeter of the Property, or 50 feet from the equipment, then appropriate measures will be taken to implement additional engineering controls to reduce the noise levels. These measures may include the following:

• Operating speed of equipment may be reduced;

• Sound barriers may be installed to deflect sound from sensitive areas if noise becomes a major issue;

• Alternate equipment may be considered; and

• Staggering of equipment operation periods may be implemented.

6.12.2 Dust

To comply with MBUAPCD rules, and the HSP, dust control measures were factored into the design of remediation. Major factors included in the design are as follows:

• Considering the size of the excavation, the area excavated will be a very manageable size for the purpose of dust control.



• The excavation equipment will be small enough that dust control measures such as water spray can be easily implemented and managed appropriately.

• The design includes providing an appropriate water source and plumbing so that adequate water supply can be provided for multiple activities at each work area. The water source may include water trucks, or tapping into a fire hydrant.

• In the event that stockpiles of impacted soil are left onsite overnight, the exposed portion will be fully covered with plastic to reduce any dust emissions.

The MBUAPCD has determined that construction activities (e.g., excavation, grading, onsite vehicles) which directly generate 82 pounds per day or more of PM10

would have a significant impact on local air quality when they are located nearby and upwind of sensitive receptors. However, District-approved PM10 dispersion modeling can be used to refute (or validate) this determination. If the modeling demonstrates that direct emissions under individual or cumulative conditions would not cause the exceedance of the State PM10 ambient air quality standard (50 micrograms per cubic meter [µg/m3]) at existing receptors as averaged over 24 hours. The proposed excavation activities at the Property are not expected to reach the MBUAPCD threshold of significance of 82 pounds per day or more of PM10. Therefore, impacts to air quality from the proposed project are expected to be less than significant.

In addition to impacts related to PM10 generated from construction activities, the MBUAPCD also has rules related to visual emissions. Rule 400 limits discharge into the atmosphere from any emission source whatsoever any air contaminant for a period or periods aggregating more than three minutes in any one hour, which is as dark or darker in shade as that designated as No. 1 on the Ringelmann Chart as published by the United States Bureau of Mines.

Detailed, continuous monitoring of dust levels is planned during construction activities. Dust levels will be monitored continuously during excavation activities and during loading of soil in addition to levels at Property boundaries. Dust levels will be controlled such that at the property lines, concentrations are below the MBUAPCD Rule 400 that the dust cloud at the edge of the project area is limited to a Ringelmann 1 or 20% opacity. If the monitoring data indicates that dust levels are beyond the targeted levels, then additional engineering control measures will be implemented to reduce the dust level.

Additionally, dust levels will be monitored for health and safety purposes as outlined in the HSP. The type and frequency of monitoring as well as the action levels for breathing and work zones are outlined in the following table.



Device Reading Location Time Period Action

Mini-Ram

<5 mg/m3 Work Area ------- Level D: Monitoring every half hour

>5 mg/m3 Work Area ------- Implement Dust Control Measures

>10 mg/m3 Work Area ------- Stop work. Evacuate upwind and notify Site Manager.

Mini-Ram

>1 mg/m3 Worker Breathing Zone 1 minute Implement Dust Control Measures

>2.5 mg/m3 (a) Worker Breathing Zone 1 minute Stop Work

(a)Based on Cal/OSHA ½-respirable particulate permissible exposure limit (PEL)

6.12.3 Odor

The primary potential odor source will be MGP wastes that may emit petroleum and/or naphthalene odors. By controlling the dust with the procedures discussed above, the emissions of any airborne contaminants will be significantly reduced to levels that pose no risk to the health of the public and remediation personnel. The water spray used to control dust will also significantly reduce the emissions of any potential volatiles that may be present in the soil. In addition, the loading and transportation of soil on a routine basis will minimize or avoid soil stockpiling, thus reducing potential emissions of volatiles. As indicated earlier any stockpile of impacted soil or exposed excavation left overnight at the Property, will be properly covered with plastic so emissions of volatiles are minimized, if not eliminated.

Based on the results of the sampling conducted during the investigation activities, air emissions of volatile organic hydrocarbons are not anticipated during remediation activities. Due to the physical characteristics of contaminants present at the Property, including PAHs, only airborne dust emissions are potentially expected. By controlling the dust as discussed in the previous section, the emissions of any airborne contaminants will be significantly reduced to levels that pose no risk to the health of the public and remediation personnel.

The water spray used to control dust will also significantly reduce the emissions of any potential volatiles that may be present in the soil, although none are expected. In addition, loading and transportation of soil on a routine basis, will minimize soil stockpiling, thus reducing potential emissions of volatiles. The equipment proposed for the remediation must have been manufactured within the past few years and maintained properly so that exhaust emissions will be within acceptable standards.

Monitoring of excavations and the Property perimeter will be conducted periodically using a flame ionization detector (FID) or photoionization detector (PID). These instruments will be calibrated daily according to the manufacturers’ specifications. If sustained elevated readings are recorded



during the remediation activities, then proper engineering control measures will be implemented to reduce the emissions of volatiles. The type and frequency of monitoring as well as the action levels for breathing and work zones are outlined in the following table.

Device Reading Location Time Period Action

OVA <5 ppm Borehole/Working Face

------- Continue hourly monitoring

OVA >5 ppm Borehole/Working Face

1 minute Stop work, proceed to next sample location

OVA 1-2 ppm Worker Breathing Zone

------- Increase monitoring frequency. Monitor every half hour.

OVA >2 ppm

Worker Breathing Zone

1 minute

Stop work; move upwind while vapors dissipate. If elevated levels remain, cover borings and spoils, evacuate upwind and notify Site Manager.

6.12.4 Decontamination

To prevent residual contamination from being left onsite by construction equipment and personnel, the following decontamination procedures have been developed:

• All equipment wheels/tires will be cleaned by means of shovels and stiff-bristled brooms or brushes until they are fully cleaned. Upon completion of cleaning, any debris will be placed in an appropriate transportation vessel.

•• Personal protective equipment (PPE), such as disposable coveralls and gloves, will be removed and discarded in the contamination reduction zone and transported offsite with impacted soil. To decontaminate reusable items such as work boots, a two-stage decontamination process will be used. This process will include washing in a detergent solution with a stiff-bristled brush and rinsing in clean water.

6.13 STORMWATER MANAGEMENT Other environmental controls may be required in the event that anticipated conditions at the Property change. In the event that remediation activities occur in the rainy season, typically considered as the period between October 15 and April 15, then water management procedures will be implemented, in addition to probable modifications of other plans such as the HSP. The following procedures will be implemented during the rainy season:

• The weather forecast will be monitored at least daily. During days when heavy rain is forecasted, remediation activities will be terminated;



• The boundary of the remediation area will be properly bermed so that no run-on enters the excavated area and no run-off leaves the excavated area;

• The run-on water from non-impacted areas will be properly discharged in the street via the natural runoff pathway. The water within the excavated area will be pumped and transported to a properly licensed disposal facility;

• Care will be exercised to ensure that mud will not stick to truck tires. The procedure may include placing plastic sheeting at the loading area; and

• Plastic sheeting will be used extensively to make sure that the area of excavation is protected from rain during off-hours and during sudden heavy rain.

In general, the excavation will be kept as dry as possible to make sure that no waste is generated, no environmental concerns arise, and that the backfilling of the excavation can be conducted promptly.

6.14 HEALTH AND SAFETY A detailed HSP will be prepared prior to remediation activities and will be used during remediation work. The HSP provides information regarding anticipated health and safety matters and establishes policies and procedures adequate to protect workers, the public, and the environment from the predicted hazards. As will be indicated in the HSP, in the event that anticipated conditions change, the HSP will be modified accordingly. The HSP will be developed as a stand-alone document and contains the following elements:

• A general description of the Property, including its location and Site map.

• Work objectives at the Property.

• A hazard evaluation, which includes the characteristics of the potential hazards to be found at the Property.

• Name of key personnel and alternates responsible for health and safety, including the appointment of a health and safety coordinator.

• Site personnel training requirements as specified by 29 CFR 1910.120 and medical surveillance requirements in addition to requirements of 8 CCR 5192.

• PPE to be used by personnel in addition to action levels and decision criteria for upgrading the levels of PPE.

• The frequency and types of personal and area air monitoring, and environmental sampling techniques and instrumentation to be used for health and safety purposes.



• Site control measures, including the designation of work zones (i.e., exclusion zone, contamination reduction zone, and support zone).

• Decontamination procedures for personnel and equipment.

• Noise control procedures and action levels.

• Dust control procedures and action levels.

• Procedures to perform safe work.

• Contingency plans for emergencies including contact names and phone numbers.

• Location of nearest medical facility for emergency medical care, as well as a map showing the route from the Property to the medical facility.

• Site safety plan consent agreement.



7.0 SAMPLING PLAN

7.1 OBJECTIVE As discussed in Section 4.0, the removal action goal developed for the Property is to minimize potential future exposure of humans (Site workers and visitors) to the COCs that may otherwise be available for ingestion, inhalation, or dermal contact. To achieve this goal, exposed impacted soil will be removed and replaced with clean fill soil, the asphalt pavement will be replaced and the deed restriction will remain in-place to further mitigate the potential for exposure to COCs. A semi-annual soil gas and groundwater monitoring program will be continued to monitor the natural attenuation processes and to verify that elevated VOC concentrations in soil gas has not migrated through vadose soils into close proximity to the building foundation.

A QA/QC plan for sampling and analyses is included as Appendix C. The plan describes the protocol and specifications for sample collection, processing, detection limits, holding times, and documentation (i.e., chain of custody).

7.2 SOIL SAMPLING 7.2.1 Number and Location of Soil Samples

Following the removal of asphalt pavement within the parking lot and the removal of near-surface soil from the planter areas, soil samples will be collected from exposed soil surfaces. Soil samples will be collected in a systematic, triangular grid pattern with approximate spacing of 30 feet. The triangular grid pattern has the following advantages:

• It is relatively easy to use; and

• It provides a uniform coverage of the area being sampled, whereas simple random or stratified random sampling can leave subareas that are not sampled.

The soil sampling plan is presented on Figure 7-1. The number and location of soil samples may be field adjusted as necessary to avoid subsurface obstructions.

7.2.2 Soil Sampling Methodology

Prior to sampling, any loose material or soil will be gently brushed off the surface. Soil samples will be collected in laboratory-supplied, glass jars with threaded Teflon®-lined lids. The soil samples will be collected by scooping soil directly into the sample jars. If soil is too dense to scoop directly into sample jars, a stainless steel spoon will be used to transfer soil into the sample jars. Sample jars will be filled with soil and lightly packed to minimize headspace in the samples. Each sample will be labeled, placed in a resealable plastic bag, and stored on ice in a cooler that will be maintained at about 4 degrees Centigrade (ºC). All samples will be shipped using appropriate chain-of-custody and shipping procedures to a California-certified laboratory and analyzed for PAH using USEPA Method 8270SIM.



Each soil sample will have a unique identification code such that the sample identification will indicate where and at what depth a sample was collected. All sample identifications will begin with the letter “P” to indicate that a particular sample is a post-closure sample, followed by the reference grid designation (e.g., A2), followed by the sequential number in a particular grid (i.e., 1, 2, 3...), and finally followed by the depth bgs. For example, the second sample collected from Grid A2 at a depth of 1 foot bgs would be labeled “PA2-2-1.”

7.3 SOIL GAS SAMPLING Initially, soil gas sampling will occur in the spring and fall to coincide with the semi-annual groundwater monitoring event. After the first five years, the sampling may be reduced if concentration trends are shown to be stable or diminishing. Soil gas sampling activities will be conducted in accordance with the procedures described below. In general, the soil gas sampling program will include the following:

• Soil gas sampling from soil vapor probes in accordance with the final design;

• Analytical laboratory testing; and

• Reporting.

Soil gas samples will be collected following protocols described below, which are based on the March 2010 “Advisory-Active Soil Gas Investigation” (ASGI) guidance document prepared by DTSC (DTSC, 2010). Soil gas sampling will not be conducted during or within a minimum of 5 days following a significant rain event (rainfall of ½ -inch or more).

Leak testing will be conducted at each soil gas sampling probe to evaluate whether a good seal has been established in the sampling train, ground surface, and probe interface. Leak testing consisting of a “vacuum shut-in test” to test the aboveground sampling equipment’s ability to hold vacuum in the tubing, valves, and connections located between the soil gas probe and SummaTM canister and a chemical tracer leak test using a leak-check compound (e.g., helium) will be conducted prior to soil gas sample collection at each soil gas probe to test the integrity of the sampling system, probe, and borehole seal. If the vacuum shut-in test fails, the tubing and valves will be changed and/or adjusted, and the test will be repeated until it passes. If the chemical tracer leak test fails, the sampling shroud and sample train connections will be checked, readjusted, and replaced as needed, and the chemical leak check test will then be repeated. If the probe continues to fail the chemical leak check test, then the probe will be properly abandoned and a replacement probe will be installed, as appropriate.

Each soil gas probe will be purged of three purge volumes prior to sample collection at a consistent purge rate ranging between 100 and 200 mL/min using a pump. Vacuums less than 100” W.C. will be maintained to minimize partitioning of vapors from pore water to soil gas, to prevent ambient air from diluting the soil gas samples, and to reduce the variability of purging rates.

Soil gas samples will be collected using clean laboratory-certified 1-liter SummaTM canisters after the soil gas probe has been appropriately purged and the leak check tests completed. A flow regulator



calibrated by the analytical laboratory to flow at a rate between 100 to 200 mL/min will be used to collect the soil gas sample in the SummaTM canister. A vacuum gauge will be also used to ensure a vacuum of less than 100” W.C. is maintained during sampling.

Per DTSC ASGI guidance, field quality control (QC) samples including either duplicate or replicate samples will be collected at a rate of one (1) duplicate/replicate sample per 20 samples or per batch shipment to the laboratory, whichever is more often. In addition, field QC samples will also include an equipment blank and a field blank. The need for a duplicate/replicate sample, equipment blank and field blank will be re-evaluated after two years of sampling has been completed.

The soil gas samples and field QC samples will be analyzed by an off-site stationary California-certified laboratory for VOCs including naphthalene using EPA Method TO-15.

Each sample will be identified by a unique identification number which will allow tracking and retrieval of information concerning a particular sample. Upon collection, each sample will be identified by sample location, depth and time of collection. The location identifier will be the soil gas probe number followed by the depth at which the sample was collected.

7.4 GROUNDWATER SAMPLING Initially, groundwater monitoring events will occur in the spring and fall to coincide with expected high and low-water periods. After the first five years, the sampling may be reduced if concentration trends are shown to be stable or diminishing. Groundwater monitoring activities will be conducted in accordance with the procedures developed for the currently ongoing groundwater monitoring program. In general, the groundwater monitoring program will include the following:

• Static water level measurements;

• Low-flow purging and sampling;

• Analytical laboratory testing; and

• Reporting.

Groundwater samples from each well, and one duplicate sample and one equipment blank sample, will be analyzed for: as TPH-e (as TPHd and TPHmo) by USEPA Method 8015B; TPH-p (as TPHg) and BTEX/MTBE by USEPA Method 8260B; PAH by USEPA Method 8270SIM; total cyanide by USEPA Method 335.2; ammonia as nitrogen by USEPA Method 350.2; and arsenic by USEPA Method 6010B. One trip blank sample will also be analyzed for TPH-p and BTEX/MTBE.

Field parameters for natural attenuation will also be collected and the results used to support the natural attenuation selection for the Property. These parameters include dissolved oxygen, redox potential, pH, reduced iron, nitrate, reduced manganese, and sulfate. The reduced iron, nitrate, reduced manganese, and sulfate concentrations will be measured in the field using Hach colorimetric testing and digital titration or similar methodology.



8.0 CEQA COMPLIANCE

The proposed remedial action will be conducted in accordance with California Environmental Quality Act (CEQA). Pursuant to CEQA Article 19 (Catagorical Exemptions) Section 15330 for Minor Actions to Prevent, Minimize, Stabilize, Mitigate or Eliminate the Release or Threat of Release of Hazardous Waste or Hazardous substances, the proposed remedial action qualifies for a Class 30 Exemption.

Class 30 exemptions consist of minor cleanup actions taken to prevent, minimize, stabilize, mitigate, or eliminate the release or threat of a release of hazardous waste or substances for small or medium sized removal actions that cost one million dollars or less. Examples of minor cleanup actions exempt from CEQA under Class 30 exemption include: removal of sealed non-leaking drums or barrels; maintenance or stabilization of berms, dikes, or surface impoundments; onsite treatment of contaminated soils or sludges; construction, maintenance or interim temporary surface caps; excavation and/or offsite disposal of contaminated soils or sludges in regulated units; application of dust suppressants or dust binders to soils; controls for surface water run-on and run-off that meet seismic safety standards; pumping of leaking ponds into an enclosed container; construction of interim or emergency groundwater treatment systems; and posting warning signs and fencing for a hazardous waste or substance site that meet legal requirements for protection of wildlife.

Once it is confirmed by the lead public agency (i.e., DTSC) that work proposed under the remedial action is exempt from CEQA, a notice of exemption will be filed by the lead public agency prior to implementation of this remedial action. This notice of exemption will include the following information:

• A brief description of the project;

• The location of the project (either by street address and cross street for a project in an urbanized area or by attaching a specific map, preferably a copy of a U.S.G.S. 15' or 7-1/2' topographical map identified by quadrangle name);

• A finding that the project is exempt from CEQA, including a citation to the State Guidelines section or statute under which it is found to be exempt; and

• A brief statement of reasons to support the finding.



9.0 PUBLIC PARTICIPATION

A Community Profile was prepared in 2000 and subsequently updated in 2009 (IT, 2000; Craig Communications, 2009) as a means to assist the DTSC in assessing the potential level of community interest in the investigation and mitigation process. Based on responses to a community survey presented in the updated Community Profile, it is anticipated that there will be low interest by the community in any environmental work at the Property.

It is anticipated that the DTSC may collect additional information to aid in the decision-making process, which may include public notices, work notices, and/or a Fact Sheets. Such items will present information about the Property history, DTSC involvement, investigation project status and remediation plans, and provide opportunities for public involvement in the decision-making process. Community concerns and comments will be summarized and responses will be prepared as appropriate.

Throughout the project, interested parties will be able to review project documents at the designated repository, the Watsonville Main Public Library located at 310 Union Street. The DTSC will solicit public comments on the draft RAW during a 30-day public comment period.



10.0 REMEDIATION SCHEDULE

The following tentative schedule is anticipated for public participation, approval of this RAW, and excavation and restoration of the Property:

Activity Duration Draft RAW Public Comment Period 1 month Finalize RAW and Distribute 1 month Site Remediation 2 months Site Draft Completion Report 2 to 3 months

This tentative schedule was projected based on information available at the time of preparation of this document and the need to implement the remediation during the summer months to avoid rain. The schedule may be modified based on potential circumstances beyond the control of PG&E.



11.0 PROPERTY CERTIFICATION

The fundamental removal action goal for the Property is to minimize potential future exposure of humans (Property workers and visitors) to the COCs that may otherwise be available for ingestion, inhalation, or dermal contact. To achieve this goal, focused soil excavation will be conducted and any remaining impacted soil will be capped with clean soil and asphalt or concrete pavement, and the deed restriction will remain in-place to further mitigate the potential for exposure to COCs.

Soil gas monitoring will be conducted to verify that soil gas conditions onsite are stable. Also, groundwater monitoring program will be continued to monitor the natural attenuation processes. Once the removal action is implemented at the Property, a Completion Report will be prepared which will detail the proposed post-remediation soil gas and groundwater monitoring program. The Completion Report will also request a certification of completion of remediation activities from DTSC.



12.0 ADMINISTRATIVE RECORD LIST

The Administrative Record List for the Property is provided below. Site-Specific Records are listed first in chronological order, followed by Regulatory Records listed in reverse chronological order. This list contains Site-Specific Records and Regulatory Records that were relied upon in evaluation and selection of the remedy for the Property.

Date Author Title of Document/Subject

Site-Specific Records

December 1986 PG&E

Preliminary Assessment of the Former Manufactured Gas Plant Site in the City of Watsonville, Site MT-CO-WAT-1.

November 1991 CH2M Hill Preliminary Endangerment Assessment, PG&E, Watsonville, California.

December 1996 DTSC Hazardous Substances Site Cleanup Agreement, Docket No. HSA 96/97-029

April 23, 1997 Smith

Workplan for Groundwater Monitoring, Pacific Gas and Electric Company’s Former Watsonville-1 Manufactured Gas Plant, 618 Main Street, Watsonville, California,

April 1999 PG&E

A Semi-annual Groundwater Monitoring and Sampling Report, prepared by, was submitted to the DTSC.

September 19, 2000 IT A Site Investigation Work Plan, prepared by the IT Corporation, was submitted to the DTSC.

September 20 2000 IT Community Profile, PG&E Watsonville-1 Former Manufactured Gas Plant Site.

December 6, 2000 IT Site Investigation Work Plan with final revisions was submitted to the DTSC.

August 2001 with Revision Pages February

2002 IT

Site Investigation Results, Pacific Gas and Electric Company Watsonville-1 Former Manufactured Gas Plant Site.

November 5, 2001 DTSC

The DTSC issued a letter to PG&E, based on review of the IT Corporation’s August 2001 Site Investigation Results Report, requesting clarifications.




March 4, 2002 IT Human Health Risk Assessment, Pacific Gas and Electric Company Watsonville-1 Former Manufactured Gas Plant Site

March 3, 2003 Shaw Memorandum: Conceptual Remedy for the Watsonville-1 MGP Site

July 18, 2003 Shaw

Groundwater Monitoring Report, April 2003, Semi-annual Groundwater Monitoring Program, Pacific Gas and Electric Company Watsonville-1 Former Manufactured Gas Plant Site

April 2004 ENV America

Fall 2003, Groundwater Monitoring Report, Pacific Gas and Electric Company, Watsonville-1 Former Manufactured Gas Plant, 618 Main Street, Watsonville, California.

March 30, 2004 DTSC Letter to PG&E with comments on the Supplemental Site Investigation Workplan.

May 6, 2004 ENV America Supplemental Site Investigation Workplan, Watsonville-1 Former Manufactured Gas Plant, 618 Main Street, Watsonville, California

August 2004 ENV America

May 2004, Groundwater Monitoring Report, Pacific Gas and Electric Company, Watsonville-1 Former Manufactured Gas Plant, 618 Main Street, Watsonville

August 9, 2004 ENV America Supplemental Site Investigation Report, Watsonville-1 Former Manufactured Gas Plant, 618 Main Street, Watsonville, California.

August 19, 2004 ENTRIX Historical and Architectural Evaluation, The PG&E Building, 618 Main Street, Watsonville, California, APN 018-151-26

January 31, 2005 ENV America

Fall 2004, Groundwater Monitoring Report, Pacific Gas and Electric Company, Watsonville-1 Former Manufactured Gas Plant, 618 Main Street, Watsonville, California.

July 2005 ENV America

Spring 2005, Groundwater Monitoring Report, Pacific Gas and Electric Company, Watsonville-1 Former Manufactured Gas Plant, 618 Main Street, Watsonville, California.

June 29, 2006 TPG

Groundwater Monitoring and Sampling Workplan, Watsonville-1 Former Manufactured Gas Plant Site, 618 Main Street, Watsonville, California.




August 25, 2006 TPG

August 2006 Groundwater Monitoring Report, Watsonville-1 Former Manufactured Gas Plant Site, 618 Main Street, Watsonville, California.

February 2, 2007 TPG

December 2006 Groundwater Monitoring Report, Watsonville-1 Former Manufactured Gas Plant Site, 618 Main Street, Watsonville, California.

August 21, 2007 TPG

June 2007 Groundwater Monitoring Report, Watsonville-1 Former Manufactured Gas Plant Site, 618 Main Street, Watsonville, California.


November 2007 Groundwater Monitoring Report, Watsonville-1 Former Manufactured Gas Plant Site, 618 Main Street, Watsonville, California.

July 18, 2008 TPG

April 2008 Groundwater Monitoring Report, Watsonville-1 Former Manufactured Gas Plant Site, 618 Main Street, Watsonville, California.


November 2008 Groundwater Monitoring Report, Watsonville-1 Former Manufactured Gas Plant Site, 618 Main Street, Watsonville, California.

July 15, 2009 TPG

April 2009 Groundwater Monitoring Report, Watsonville-1 Former Manufactured Gas Plant Site, 618 Main Street, Watsonville, California.

July 27, 2009 TPG

Additional Subsurface Investigation Report, Watsonville-1 Former Manufactured Gas Plant Site, 618 Main Street, Watsonville, California.

September 30, 2009 TPG and Iris

Environmental

Contingency Plan for Soil Gas Sampling, Watsonville-1 Former Manufactured Bas Plant


Soil Gas Probe and Groundwater Monitoring Well Installation Report, Former Watsonville-1 Manufactured Gas Plant Site, 618 Main Street, Watsonville, California





October 2009 Groundwater and Soil Gas Monitoring Report, Watsonville-1 Former Manufactured Gas Plant Site, 618 Main Street, Watsonville, California.

April 22, 2010 Iris Environmental

Draft Screening-Level Vapor Intrusion and Soil Health Risk Evaluation, Former Watsonville-1 Manufactured Gas Plant Site, 618 Main Street, Watsonville, California.

Regulatory Records

October 2005 (last updated)

California Environmental Protection Agency

(CAL/EPA)

California Code of Regulations (CCR) Title 22, Division 4.5, Chapter 10, Article 2: Soluble Threshold Limit Concentration (STLC)

January 2005 (Statute Amended)

September 2004 Guidelines Amended 1970 (established)

CAL/EPA

California Environmental Quality Act (CEQA) Statute: California Public Resource Code (CPRC) Division 13, Environmental Protection Guidelines: CCR Title 14, Chapter 3 Guidelines for Implementation of CEQA

January 2005 (last updated)

CAL/EPA Porter-Cologne Water Quality Control Act California Water Code Division 7, Section 13000

November 2004 (last updated)

CAL/EPA California Safe Drinking Water Act and Toxic Enforcement Act: CCR Title 22 Division 4, Article 4, Section 64431

June 2004 Monterey Bay Unified Air Pollution Control District

(MBUAPCD)

CEQA Air Quality Guidelines

July 2002 USEPA USEPA National Primary Drinking Water Standards pursuant to 40 CFR Chapter 1 Subpart B Section 141.62

January 2002 (revised)

USEPA

USEPA 40 Code of Federal Regulations (CFR) 300.430(e)(2)(i) for establishment of site-specific remedial action goals that are protective of human health and the environment

October 2001 Department of Toxic Substances Control

(DTSC)

Department of Toxic Substances Control, Public Policy and Procedures Manual, EO-94-002-PP

August 2001 RMC

(Raines, Melton & Carella, Inc.,)

Draft Revised Basin Management Plan, prepared for the Pajaro Valley Water Management Agency




State of California -Division of Occupational

Safety and Health (DOSH)

California Occupational Safety and Health Act (OSHA) and CCR Title 8, Division 1, Chapter 3.2. California Occupational Safety and Health Regulations Subchapter 2. Regulations of the Division of Occupational Safety and Health

January 1999 CAL/EPA, Air Resources

Control Board

Hazardous Waste Control Act Health and Safety Code Chapter 6.5, Section 25100-25250.26

March 1996 (established)

USEPA USEPA 29 CFR Part 1910.120 for Occupational Health and Safety (OSHA) Hazardous Waste Operations and Emergency Response

October 1995 Rice et al.

Recommendations to Improve the Cleanup Process for California’s Leaking Underground Fuel Tanks (LUFTs), Lawrence Livermore National Laboratory

October 1994 (revised)

March 1990 (established)

USEPA

USEPA National Oil and Hazardous Substance Pollution Contingency Plan (NCP pursuant to 40 CFR Part 300

September 1994 Central Coast Regional Water Quality Control

Board

Water Quality Control Plan for the Central Coast Region (Basin Plan)

December 1993 USEPA USEPA Guidance on Conducting Non-Time Critical Removal Actions Under CERCLA, EPA/540-R-93-057.

December 1980 USEPA USEPA Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), also known as Superfund

June 1972 K.S. Muir

Geology and Groundwater of the Pajaro Valley Area, Santa Cruz and Monterey Counties, California, Unites States Geological Survey, Water Resources Division, Open File Report 73-199

1972 (established) USEPA Clean Water Act, 33 USC 1251-1387

1967 (established) CAL/EPA Air Resources

Board Mulford-Carrell Air Resources Act Health and Safety Code Section 39000 et seq.

1963 (established) United States Code

(USC) Clean Air Act, 42 USC 7401, and 40 CFR 50-80

(1) Document and pertinent correspondence references are included in Section 13 (references)



13.0 REFERENCES CITED

CH2M Hill. 1991. Preliminary Endangerment Assessment, PG&E, Watsonville, California. Volumes I, II and III. November.

California Environmental Protection Agency (Cal/EPA). 1994. California Cancer Potency Factors: Update. Memorandum from the Standards and Criteria Work Group of the Office of Environmental Health Hazard Assessment (OEHHA) to the Cal/EPA Departments, Boards, and Office. Sacramento, California. November 1.

Cal/EPA, Department of Toxic Substances Control (DTSC). 2001. Fact Sheet: Information Advisory, Clean Imported Fill Material. October.

Cal/EPA, DTSC. 2010. Draft Advisory – Active Soil Gas Investigation. March.

ENTRIX, Inc. (ENTRIX). 2004. Historical and Architectural Evaluation, The PG&E Building, 618 Main Street, Watsonville, California, APN 018-151-26. August 19.

ENV America Incorporated (ENV America). 2004. Supplemental Site Investigation Report, Watsonville-1 Former Manufactured Gas Plant, 618 Main Street, Watsonville, California. August 9.

Iris Environmental. 2010. Draft Screening-Level Vapor Intrusion and Soil Health Risk Evaluation, Former Watsonville-1 Manufactured Gas Plant Site, 618 Main Street, Watsonville, California. April 22.

IT Corporation. 2000. Community Profile, PG&E Watsonville-1 Former Manufactured Gas Plant Site. September 20.

IT Corporation. 2001. Site Investigation Results, Pacific Gas and Electric Company Watsonville-1 Former Manufactured Gas Plant Site. August 2001, with Revision Pages February 2002.

IT Corporation, 2002. Human Health Risk Assessment, Pacific Gas and Electric Company Watsonville-1 Former Manufactured Gas Plant Site. March 4.

Muir, K.S. 1972. Geology and Ground Water of the Pajaro Valley Area, Santa Cruz and Monterey Counties, California, United States Geological Survey, Water Resources Division, Open File Report 73-199. June 27.

Pacific Gas and Electric Company. 1986. Preliminary Assessment of the Former Manufactured Gas Plant Site in the City of Watsonville, Site MT-CO-WAT-1. December.

Pajaro Valley Water Management Agency (PVWMA). 2001. State of the Basin Report. August.

Raines, Melton & Carella, Inc. (RMC). 2001. Draft Revised Basin Management Plan, prepared for the Pajaro Valley Water Management Agency. August.

Shaw Environmental, Inc. (Shaw). 2003. Memorandum: Conceptual Remedy for the Watsonville-1 MGP Site. March 3.

Terra Pacific Group (TPG). 2009. Additional Subsurface Investigation Report, Former Watsonville-1 Manufactured Gas Plant Site, 618 Main Street, Watsonville, California. July 27.



TPG. 2010a. October 2009 Groundwater and Soil Gas Monitoring Report, Former Watsonville-1 Manufactured Gas Plant Site, 618 Main Street, Watsonville, California. February 3.

TPG. 2010b. Soil Gas Probe and Groundwater Monitoring Well Installation Report, Former Watsonville-1 Manufactured Gas Plant Site, 618 Main Street, Watsonville, California. February 3.

TPG and Iris Environmental. 2009. Contingency Plan for Soil Gas Sampling, Watsonville-1 Former Manufactured Gas Plant. September 30.

TABLES

Table 2-1ASummary of PAH Concentrations in Soil Samples

Former Watsonville-1 MGP SiteWatsonville, California

Page 1 of 16

Boring ID MT-408-8-1 DSS-WAT1-1 DSS-WAT1-2 DSS-WAT1-3 DSS-WAT1-4

Sample ID MT-408-8-1 DSS-WAT1-1 DSS-WAT1-2 DSS-WAT1-3 DSS-WAT1-4 DSS-WAT1-5 DUPLICATEDSS-WAT1-5 B-WAT1-1-3.5-5 B-WAT1-1-10-11.5 B-WAT1-1-15-16.5

Sample Depth (feet bgs) 0 0 0 0 0 0 0 3.5-5 10-11.5 15-16.5Sample Date 6/30/1986 6/24/1991 6/24/1991 6/24/1991 6/24/1991 6/24/1991 6/24/1991 6/23/1991 6/23/1991 6/23/1991

Laboratory McKesson CH2M Hill CH2M Hill CH2M Hill CH2M Hill CH2M Hill CH2M Hill CH2M Hill CH2M Hill CH2M HillNon-Carcinogenic

Acenaphthylene 0.14 ND<0.076 ND<0.74 ND<0.76 ND<0.076 ND<0.72 ND<0.36 ND<0.078 ND<0.079 ND<0.076Acenaphthene 0.06 ND<0.076 ND<0.74 ND<0.76 ND<0.076 ND<0.72 ND<0.36 ND<0.078 ND<0.079 ND<0.076

Anthracene 0.13 ND<0.076 ND<0.74 ND<0.76 ND<0.076 ND<0.72 ND<0.36 ND<0.078 ND<0.079 ND<0.076Benzo(g,h,i)perylene 0.33 0.16 ND<0.74 ND<0.76 0.16 0.74 ND<0.36 ND<0.078 ND<0.079 ND<0.076

Fluoranthene 0.88 0.15 3.2 1.1 0.16 ND<0.72 0.51 ND<0.078 ND<0.079 ND<0.076Fluorene 0.04 ND<0.076 ND<0.74 ND<0.76 ND<0.076 ND<0.72 ND<0.36 ND<0.078 ND<0.079 ND<0.076

Phenanthrene 0.49 ND<0.076 1.3 ND<0.76 ND<0.076 ND<0.72 ND<0.36 ND<0.078 ND<0.079 ND<0.076Pyrene 0.77 ND<0.076 ND<0.74 ND<0.76 ND<0.076 ND<0.72 ND<0.36 ND<0.078 ND<0.079 ND<0.076

CarcinogenicBenzo(a)anthracene 0.41 ND<0.076 1.4 ND<0.76 0.092 ND<0.72 ND<0.36 ND<0.078 ND<0.079 ND<0.076

Benzo(a)pyrene 0.4 0.11 2.2 0.95 0.16 ND<0.72 0.46 ND<0.078 ND<0.079 ND<0.076Benzo(b)fluoranthene 0.43 0.33 2.6 1.5 0.34 1.3 0.88 ND<0.078 ND<0.079 ND<0.076Benzo(k)fluoranthene 0.27 0.08 ND<0.74 ND<0.76 0.077 ND<0.72 ND<0.36 ND<0.078 ND<0.079 ND<0.076

Chrysene 0.53 ND<0.076 1.4 ND<0.76 ND<0.076 ND<0.72 ND<0.36 ND<0.078 ND<0.079 ND<0.076Dibenzo(a,h)anthracene 0.05 0.17 1.4 0.87 0.19 0.75 0.57 ND<0.078 ND<0.079 ND<0.076Indeno(1,2,3-cd)pyrene 0.35 0.22 1 0.93 0.21 0.94 0.58 ND<0.078 ND<0.079 ND<0.076

Naphthalene 0.23 ND<0.076 ND<0.74 ND<0.76 ND<0.076 ND<0.72 ND<0.36 ND<0.078 ND<0.079 ND<0.076B(a)P Equivalent 0.568 0.235 3.227 1.569 0.297 0.915 0.838 0.068 0.069 0.067

Notes:All results are presented in milligrams per kilogram (mg/kg).Samples were analyzed by USEPA Method 8310, except for samples collected in 2008 which were analyzed using USEPA Method 8270 SIM."ND<" indicates the constituent was not detected at or above the laboratory reporting limit or method detection limit.Benzo(a)pyrene equivalents represent the sum of the concentration of each carcinogenic PAH multiplied by its toxicity equivalence factor (except for naphthalene).B(a)P = benzo(a)pyrenebgs = below ground surfacePAH = polycyclic aromatic hydrocarbonUSEPA = United States Environmental Protection AgencyD = sample diluted to bring the analyte concentration within calibration rangeJ = estimated value; analyte detected at a concentration less than the reporting limit and greater than or equal to the method detection limit

DSS-WAT1-5 B-WAT1-1



Page 2 of 16

Boring ID

Sample IDSample Depth (feet bgs)

Sample DateLaboratory

Non-CarcinogenicAcenaphthyleneAcenaphthene

AnthraceneBenzo(g,h,i)perylene

FluorantheneFluorene

PhenanthrenePyrene

CarcinogenicBenzo(a)anthracene

Benzo(a)pyreneBenzo(b)fluorantheneBenzo(k)fluoranthene

ChryseneDibenzo(a,h)anthraceneIndeno(1,2,3-cd)pyrene

NaphthaleneB(a)P Equivalent

MW-WAT1-1-3-5 MW-WAT1-1-8-10 MW-WAT1-1-12-13 MW-WAT1-1-18-19 MW-WAT1-1-20-21.5

3.0-5.0 8.0-10.0 12.0-13.0 18.0-19.0 20-21.56/22/1991 6/22/1991 6/22/1991 6/22/1991 6/22/1991CH2M Hill CH2M Hill CH2M Hill CH2M Hill CH2M Hill

ND<0.078 ND<0.078 ND<0.077 ND<0.075 ND<0.074ND<0.078 ND<0.078 ND<0.077 ND<0.075 ND<0.074ND<0.078 ND<0.078 ND<0.077 ND<0.075 ND<0.074ND<0.078 ND<0.078 ND<0.077 ND<0.075 ND<0.074ND<0.078 ND<0.078 ND<0.077 ND<0.075 ND<0.074ND<0.078 ND<0.078 ND<0.077 ND<0.075 ND<0.074ND<0.078 ND<0.078 ND<0.077 ND<0.075 ND<0.074ND<0.078 ND<0.078 ND<0.077 ND<0.075 ND<0.074

ND<0.078 ND<0.078 ND<0.077 ND<0.075 ND<0.074ND<0.078 ND<0.078 ND<0.077 ND<0.075 ND<0.074ND<0.078 ND<0.078 ND<0.077 ND<0.075 ND<0.074ND<0.078 ND<0.078 ND<0.077 ND<0.075 ND<0.074ND<0.078 ND<0.078 ND<0.077 ND<0.075 ND<0.074ND<0.078 ND<0.078 ND<0.077 ND<0.075 ND<0.074ND<0.078 ND<0.078 ND<0.077 ND<0.075 ND<0.074ND<0.078 ND<0.078 ND<0.077 ND<0.075 ND<0.074

0.068 0.068 0.067 0.066 0.065


MW-WAT1-1



Page 3 of 16

Boring ID






PhenanthrenePyrene





MW-WAT1-2-4-5 MW-WAT1-2-5-6.5 MW-WAT1-2-10-11.5 MW-WAT1-2-11.5-13 MW-WAT1-2-13-15 DUPLICATEMW-WAT1-2-13-15 MW-WAT1-2-15-16.5

4.0-5.0 5.0-6.5 10-11.5 11.5-13 13-15 13-15 15-16.56/23/1991 6/23/1991 6/23/1991 6/23/1991 6/23/1991 6/23/1991 6/23/1991CH2M Hill CH2M Hill CH2M Hill CH2M Hill CH2M Hill CH2M Hill CH2M Hill

ND<0.78 ND<0.76 ND<0.076 ND<0.076 0.4 ND<3.8 ND<0.077ND<0.78 ND<0.76 ND<0.076 ND<0.076 ND<0.39 ND<3.8 ND<0.077ND<0.78 ND<0.76 ND<0.076 ND<0.076 3.7 14 ND<0.077

1.4 0.84 ND<0.076 ND<0.076 ND<0.39 ND<3.8 ND<0.0775.9 3.8 ND<0.076 ND<0.076 3.4 15 ND<0.077

ND<0.78 ND<0.76 ND<0.076 ND<0.076 3.4 11 ND<0.0772.2 1.2 ND<0.076 ND<0.076 6.5 27 ND<0.077

ND<0.78 ND<0.76 ND<0.076 ND<0.076 ND<0.39 ND<3.8 ND<0.077

3.4 2.2 ND<0.076 ND<0.076 0.68 4.8 ND<0.0776.7 4.2 ND<0.076 ND<0.076 0.97 6.3 ND<0.0777.6 4.4 ND<0.076 ND<0.076 0.91 4.7 ND<0.0771.5 0.88 ND<0.076 ND<0.076 ND<0.39 ND<3.8 ND<0.077

ND<0.78 ND<0.76 ND<0.076 ND<0.076 ND<0.39 ND<3.8 ND<0.0775.1 2.3 ND<0.076 ND<0.076 1 7.1 ND<0.0774.2 2.1 ND<0.076 ND<0.076 ND<0.39 ND<3.8 ND<0.077

ND<0.78 ND<0.76 ND<0.076 ND<0.076 ND<0.39 ND<3.8 ND<0.077

10.108 5.944 0.067 0.067 1.510 10.063 0.067

Notes:All results are presented in milligrams per kilogram (mg/kg).Samples were analyzed by USEPA Method 8310, except for samples collected in 2008 which were analyzed using USEPA Method 8270 SIM."ND<" indicates the constituent was not detected at or above the laboratory reporting limit or method detection limit.Benzo(a)pyrene equivalents represent the sum of the concentration of each carcinogenic PAH multiplied by its toxicity equivalence factor (except for naphthalene).B(a)P = Benzo(a)pyrenebgs = below ground surfacePAH = polycyclic aromatic hydrocarbonUSEPA = United States Environmental Protection AgencyD = sample diluted to bring the analyte concentration within calibration rangeJ = estimated value; analyte detected at a concentration less than the reporting limit and greater than or equal to the method detection limit

MW-WAT1-2



Page 4 of 16

Boring ID






PhenanthrenePyrene





MW-WAT1-3-3.5-6 MW-WAT1-3-10-11.5 MW-WAT1-3-13-15 DUPLICATEMW-WAT1-3-13-15 MW-WAT1-3-15-16.5 MW-WAT1-3-18-20 MW-WAT1-3-20-21.5 MW-WAT1-3-23-25 MW-WAT1-3-25-26.5

3.5-6 10-11.5 13-15 13-15 15-16.5 18-20 20-21.5 23-25 25-26.56/24/1991 6/24/1991 6/24/1991 6/24/1991 6/24/1991 6/24/1991 6/24/1991 6/24/1991 6/24/1991CH2M Hill CH2M Hill CH2M Hill CH2M Hill CH2M Hill CH2M Hill CH2M Hill CH2M Hill CH2M Hill

ND<0.077 ND<0.79 120 8.4 65 ND<0.76 ND<0.079 ND<0.076 ND<0.076ND<0.077 ND<0.79 630 ND<0.38 ND<3.8 ND<0.76 ND<0.079 ND<0.076 ND<0.076ND<0.077 0.94 19 5 21 ND<0.76 ND<0.079 ND<0.076 ND<0.076ND<0.077 ND<0.79 ND<3.8 ND<0.38 ND<3.8 ND<0.76 ND<0.079 ND<0.076 ND<0.076ND<0.077 7.8 31 6.4 27 1 ND<0.079 ND<0.076 ND<0.076ND<0.077 ND<0.79 ND<3.8 5.1 19 ND<0.76 ND<0.079 ND<0.076 ND<0.076ND<0.077 2.6 80 13 54 2 ND<0.079 ND<0.076 ND<0.076ND<0.077 12 ND<3.8 ND<0.38 ND<3.8 ND<0.76 ND<0.079 ND<0.076 ND<0.076

ND<0.077 5.4 12 2.3 10 ND<0.76 ND<0.079 ND<0.076 ND<0.076ND<0.077 8.1 11 2.4 8.4 ND<0.76 ND<0.079 ND<0.076 ND<0.076ND<0.077 6.7 9.3 1.8 8.4 ND<0.76 ND<0.079 ND<0.076 ND<0.076ND<0.077 1.7 ND<3.8 0.5 ND<3.8 ND<0.76 ND<0.079 ND<0.076 ND<0.076

0.079 ND<0.79 ND<3.8 ND<0.38 ND<3.8 ND<0.76 ND<0.079 ND<0.076 ND<0.076ND<0.077 7 11 2.3 8.5 ND<0.76 ND<0.079 ND<0.076 ND<0.076ND<0.077 2 ND<3.8 0.5 ND<3.8 ND<0.76 ND<0.079 ND<0.076 ND<0.076ND<0.077 ND<0.79 73 5.8 59 ND<0.76 ND<0.079 ND<0.076 ND<0.076

0.068 12.064 17.269 3.694 13.529 0.665 0.069 0.067 0.067


MW-WAT1-3



Page 5 of 16

Boring ID






PhenanthrenePyrene





SS-WAT1-1-1-12" SS-WAT1-1-1-30" SS-WAT1-2-1-12" DUPLICATESS-WAT1-2-2-12" SS-WAT1-2-1-30" SS-WAT1-3-1-12" SS-WAT1-3-1-30" SS-WAT1-4-1-12" SS-WAT1-0401

1 2.5 1 1 2.5 1 2.5 1 2.53/14/2001 3/14/2001 3/14/2001 3/14/2001 3/14/2001 3/14/2001 3/14/2001 3/14/2001 3/26/2001

STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab

ND<0.01 ND<0.01 ND<0.01 ND<0.05 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.5ND<0.01 ND<0.01 ND<0.01 ND<0.05 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.5ND<0.005 ND<0.005 ND<0.005 ND<0.025 ND<0.005 0.011 ND<0.005 0.015 2ND<0.01 ND<0.01 ND<0.01 ND<0.05 ND<0.01 ND<0.01 ND<0.01 0.1 2

0.027 0.0098 ND<0.005 0.063 ND<0.005 0.12 0.016 0.2 15ND<0.005 ND<0.005 ND<0.005 ND<0.025 ND<0.005 ND<0.005 ND<0.005 ND<0.005 2

0.016 ND<0.005 ND<0.005 ND<0.025 ND<0.005 0.052 ND<0.005 0.063 6.40.026 0.0064 0.03 0.052 0.0061 0.18 0.015 0.28 16

0.01 0.0053 0.0094 ND<0.025 ND<0.005 0.047 0.006 0.12 5.8ND<0.005 ND<0.005 0.01 ND<0.025 ND<0.005 ND<0.005 ND<0.005 0.17 4.5ND<0.005 ND<0.005 ND<0.005 ND<0.025 ND<0.005 ND<0.005 ND<0.005 0.13 ND<0.25ND<0.005 ND<0.005 ND<0.005 ND<0.025 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.25

0.012 0.0052 0.01 ND<0.025 ND<0.005 0.035 0.0065 0.1 4.6ND<0.01 ND<0.01 ND<0.01 ND<0.05 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.5ND<0.01 ND<0.01 ND<0.01 ND<0.05 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.5ND<0.015 ND<0.015 ND<0.015 ND<0.075 ND<0.015 ND<0.015 ND<0.015 ND<0.015 ND<0.75

0.006 0.006 0.014 0.027 0.005 0.010 0.006 0.198 5.261


SS-WAT1-2 SS-WAT1-3 SS-WAT1-4SS-WAT1-1



Page 6 of 16

Boring ID






PhenanthrenePyrene





SS-WAT1-5-1-12" SS-WAT1-0501 SS-WAT1-6-1-12" SS-WAT1-6-1-30" SS-WAT1-7-1-12" SS-WAT1-7-1-30" SS-WAT1-8-1-12" SS-WAT1-8-1-30" SS-WAT1-9-1-12" SS-WAT1-9-1-30"

1 2.5 1 2.5 1 2.5 1 2.5 1 2.53/14/2001 3/26/2001 3/14/2001 3/14/2001 3/14/2001 3/14/2001 3/14/2001 3/14/2001 3/14/2001 3/14/2001

STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab

ND<0.5 ND<0.01 ND<0.05 ND<0.05 ND<0.01 ND<0.01 ND<0.01 ND<0.05 ND<0.05 ND<0.01ND<0.5 ND<0.01 ND<0.05 ND<0.05 ND<0.01 ND<0.01 ND<0.01 ND<0.05 ND<0.05 ND<0.01

1.5 ND<0.005 0.38 0.12 0.039 ND<0.005 ND<0.005 ND<0.025 ND<0.025 ND<0.0052.5 ND<0.01 ND<0.05 ND<0.05 ND<0.01 ND<0.01 ND<0.01 ND<0.05 ND<0.05 ND<0.0120 0.033 2.9 1.2 0.35 0.034 ND<0.005 0.16 ND<0.025 ND<0.005

ND<0.25 ND<0.005 ND<0.025 ND<0.025 ND<0.005 ND<0.005 ND<0.005 ND<0.025 ND<0.025 ND<0.0053.3 ND<0.005 1.3 0.66 0.13 0.015 ND<0.005 0.072 ND<0.025 ND<0.00518 0.016 4.6 2 0.48 0.1 ND<0.005 0.18 ND<0.025 ND<0.005

10 0.016 1.5 ND<0.025 ND<0.005 0.032 ND<0.005 0.096 ND<0.025 ND<0.0058.7 0.026 1.7 0.6 ND<0.005 ND<0.005 ND<0.005 0.13 ND<0.025 ND<0.0056.2 ND<0.005 ND<0.025 ND<0.025 ND<0.005 ND<0.005 ND<0.005 ND<0.025 ND<0.025 ND<0.0053.2 ND<0.005 ND<0.025 ND<0.025 ND<0.005 ND<0.005 ND<0.005 ND<0.025 ND<0.025 ND<0.0056.7 0.018 0.83 0.37 ND<0.005 0.028 ND<0.005 0.071 ND<0.025 ND<0.005

ND<0.5 ND<0.01 ND<0.05 ND<0.05 ND<0.01 ND<0.01 ND<0.01 ND<0.05 ND<0.05 ND<0.01ND<0.5 ND<0.01 ND<0.05 ND<0.05 ND<0.01 ND<0.01 ND<0.01 ND<0.05 ND<0.05 ND<0.01ND<0.75 ND<0.015 ND<0.075 ND<0.075 ND<0.015 ND<0.015 ND<0.015 ND<0.075 ND<0.075 ND<0.015

10.817 0.030 1.872 0.618 0.005 0.009 0.005 0.154 0.027 0.005


SS-WAT1-8 SS-WAT1-9SS-WAT1-5 SS-WAT1-6 SS-WAT1-7



Page 7 of 16

Boring ID






PhenanthrenePyrene





B-WAT1-2-1-6.5 B-WAT1-2-1-10 B-WAT1-2-1-15 B-WAT1-3-1-6.5 B-WAT1-3-1-10 DUPLICATEB-WAT1-3-2-10 B-WAT1-3-1-15

6.5 10 15 6.5 10 10 153/13/2001 3/13/2001 3/13/2001 3/13/2001 3/13/2001 3/13/2001 3/13/2001

STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab

ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005

ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01ND<0.015 ND<0.015 ND<0.015 ND<0.015 ND<0.015 ND<0.015 ND<0.015

0.005 0.005 0.005 0.005 0.005 0.005 0.005


B-WAT1-2 B-WAT1-3



Page 8 of 16

Boring ID






PhenanthrenePyrene





MW-WAT1-4-1-6.5 MW-WAT1-4-1-10 MW-WAT1-4-1-15 MW-WAT1-4-1-20 MW-WAT1-5-1-6.5 MW-WAT1-5-1-10 MW-WAT1-5-1-15 MW-WAT1-5-1-20 DUPLICATEMW-WAT1-5-2-20

6.5 10 15 20 6.5 10 15 20 203/13/2001 3/13/2001 3/13/2001 3/13/2001 3/14/2001 3/14/2001 3/14/2001 3/14/2001 3/14/2001

STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab

ND<0.01 ND<0.01 ND<0.01 ND<0.05 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01ND<0.01 ND<0.01 ND<0.01 ND<0.05 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01ND<0.005 ND<0.005 ND<0.005 0.86 0.025 ND<0.005 ND<0.005 ND<0.005 ND<0.005ND<0.01 ND<0.01 ND<0.01 ND<0.05 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01

0.046 0.01 ND<0.005 2.5 0.32 ND<0.005 ND<0.005 ND<0.005 ND<0.005ND<0.005 ND<0.005 ND<0.005 0.3 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005ND<0.005 ND<0.005 ND<0.005 ND<0.025 0.071 ND<0.005 ND<0.005 ND<0.005 ND<0.005

0.039 0.0072 ND<0.005 0.81 0.51 ND<0.005 ND<0.005 ND<0.005 ND<0.005

0.024 0.0059 ND<0.005 0.62 0.2 ND<0.005 ND<0.005 ND<0.005 ND<0.005ND<0.005 ND<0.005 ND<0.005 0.51 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005ND<0.005 ND<0.005 ND<0.005 ND<0.025 0.13 ND<0.005 ND<0.005 ND<0.005 ND<0.005ND<0.005 ND<0.005 ND<0.005 ND<0.025 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005

0.017 ND<0.005 ND<0.005 0.37 0.15 ND<0.005 ND<0.005 ND<0.005 ND<0.005ND<0.01 ND<0.01 ND<0.01 ND<0.05 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01ND<0.01 ND<0.01 ND<0.01 ND<0.05 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01ND<0.015 ND<0.015 ND<0.015 ND<0.075 ND<0.015 ND<0.015 ND<0.015 ND<0.015 ND<0.015

0.008 0.006 0.005 0.589 0.039 0.005 0.005 0.005 0.005


MW-WAT1-4 MW-WAT1-5



Page 9 of 16

Boring ID






PhenanthrenePyrene





HA1-0-0.5 HA1-2.5-3 HA1-4-4.5 HA2-0-0.5 DUP 2 HA2-1-1.5 HA2-2.5-3 HA2-4-4.5 HA3-0-0.5 HA3-1-1.5 HA3-2.5-3 HA3-4-4.5

0-0.5 2.5-3 4-4.5 0-0.5 0-0.5 1-1.5 2.5-3 4-4.5 0-0.5 1-1.5 2.5-3 4-4.55/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience

0.62 ND<0.032 ND<0.032 0.056 0.45 0.034J ND<0.032 ND<0.032 0.32 ND<0.032 0.12 ND<0.032ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019

0.12 ND<0.0019 ND<0.0019 0.0032J 0.23 ND<0.0019 ND<0.0019 ND<0.0019 0.38 0.16 0.027J ND<0.00190.053 ND<0.0047 ND<0.0047 0.11 0.29 ND<0.0047 ND<0.0047 ND<0.0047 0.48 0.33 0.07 ND<0.00471.2 0.007J ND<0.0049 0.33 2.4D 0.011J ND<0.0049 ND<0.0049 3.6D 1.6 0.22 ND<0.0049

0.041J ND<0.016 ND<0.016 ND<0.016 0.082 ND<0.016 ND<0.016 ND<0.016 0.07 0.041J 0.024J ND<0.0160.44 0.0051J 0.0042J 0.094 0.57 0.0046J ND<0.0022 ND<0.0022 0.96 0.55 0.09 ND<0.00220.15 0.0082J ND<0.0031 0.14 0.94 ND<0.0031 0.062J ND<0.0031 1.6D 0.58 0.095 ND<0.0031

0.68 0.003J ND<0.0029 0.19 1.3D 0.0032J ND<0.0029 ND<0.0029 2.5D 0.88 0.11 ND<0.00290.46 0.0049J ND<0.0032 0.16 0.97 0.0062J ND<0.0032 ND<0.0032 2.0D 0.87 0.13 ND<0.00320.34 ND<0.0035 ND<0.0035 0.15 0.69 ND<0.0035 ND<0.0035 ND<0.0035 1.7D 0.49 0.12 ND<0.00350.19 ND<0.0022 ND<0.0022 0.06 0.39 ND<0.0022 ND<0.0022 ND<0.0022 0.61 0.45 0.061 ND<0.00220.11 0.003J ND<0.0026 0.18 1.2D 0.0055J 0.0027J ND<0.0026 2.3D 0.82 0.14 ND<0.0026

ND<0.0044 ND<0.0044 ND<0.0044 ND<0.0044 ND<0.0044 0.0087J ND<0.0044 ND<0.0044 ND<0.0044 0.035J ND<0.0044 ND<0.00440.27 0.024J ND<0.0025 0.079 0.51 0.0037J 0.0075J ND<0.0025 0.85 0.45 0.098 ND<0.0025

ND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026

0.610 0.009 0.003 0.210 1.272 0.010 0.004 0.003 2.590 1.117 0.171 0.003


HA1 HA2 HA3



Page 10 of 16

Boring ID






PhenanthrenePyrene





HA4-0-0.5 HA4-2.5-3 HA4-4-4.5 HA5-0-0.5 HA5-2.5-3 HA5-4-4.5 HA6-0-0.5 HA6-1-1.5 HA6-2.5-3 HA6-3-3.5 HA6-4-4.5

0-0.5 2.5-3 4-4.5 0-0.5 2.5-3 4-4.5 0 - 0.5 1-1.5 2.5-3 3-3.5 4-4.55/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience

ND<0.032 ND<0.032 ND<0.032 0.041J ND<0.032 ND<0.032 0.034J ND<0.032 ND<0.032 ND<0.032 ND<0.032ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.0190.0051J 0.0044J ND<0.0019 0.017J ND<0.0019 ND<0.0019 0.069 0.023J ND<0.0019 ND<0.0019 ND<0.0019

0.33 ND<0.0047 ND<0.0047 0.043J ND<0.0047 ND<0.0047 0.35 0.076 0.0089J ND<0.0047 ND<0.00470.16 0.0092J ND<0.0049 0.14 ND<0.0049 ND<0.0049 0.7 0.26 0.0067J 0.0087J ND<0.0049

ND<0.016 ND<0.016 ND<0.016 ND<0.016 ND<0.016 ND<0.016 0.021J ND<0.016 ND<0.016 ND<0.016 ND<0.0160.027J 0.012J ND<0.0022 0.057 ND<0.0022 ND<0.0022 0.29 0.079 ND<0.0022 0.0039J ND<0.0022

ND<0.0031 0.011J ND<0.0031 0.082 ND<0.0031 ND<0.0031 0.4 0.1 ND<0.0031 ND<0.0031 ND<0.0031

0.051 ND<0.0029 ND<0.0029 0.091 ND<0.0029 ND<0.0029 0.29 0.17 0.0034J 0.0029J ND<0.00290.19 ND<0.0032 ND<0.0032 0.13 ND<0.0032 ND<0.0032 0.54 0.17 0.0097J 0.0067J ND<0.00320.13 ND<0.0035 ND<0.0035 0.081 ND<0.0035 ND<0.0035 0.49 0.15 0.0054J ND<0.0035 ND<0.00350.15 ND<0.0022 ND<0.0022 0.055 ND<0.0022 ND<0.0022 0.2 0.064 0.0033J 0.0028J ND<0.00220.06 ND<0.0026 ND<0.0026 0.082 ND<0.0026 ND<0.0026 0.41 0.18 0.0034J 0.0039J ND<0.0026

ND<0.0044 ND<0.0044 ND<0.0044 ND<0.0044 ND<0.0044 ND<0.0044 0.36 0.065 ND<0.0044 ND<0.0044 ND<0.00440.089 ND<0.0025 ND<0.0025 0.091 ND<0.0025 ND<0.0025 0.19 0.1 0.029J ND<0.0025 ND<0.0025

ND<0.026 ND<0.026 0.026J ND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026

0.233 0.003 0.003 0.163 0.003 0.003 0.784 0.242 0.015 0.008 0.003


HA4 HA5 HA6



Page 11 of 16

Boring ID






PhenanthrenePyrene





HA7-0-0.5 DUP 1 HA7-1-1.5 HA7-2.5-3 HA7-4-4.5 HA8-0-0.5 HA8-1.5-2 HA8-2.5-3 HA8-4-4.5 HA10-0-0.5 HA10-1.5-2 HA10-2.5-3

0-0.5 0-0.5 1-1.5 2.5-3 4-4.5 0-0.5 1.5-2 2.5-3 4-4.5 0-0.5 1.5-2 2.5-35/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience

ND<0.320 ND<0.032 ND<0.032 ND<0.032 ND<0.032 ND<0.032 0.32 ND<0.032 ND<0.032 ND<0.032 ND<0.032 ND<0.032ND<0.190 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019

0.033J 0.025J ND<0.0019 ND<0.0019 ND<0.0019 0.0069J 0.096 ND<0.0019 0.0021J 0.018J 0.029J 0.0024J0.92 0.42 0.0089J ND<0.0047 ND<0.0047 0.087 0.21 ND<0.0047 ND<0.0047 0.45 0.039J 0.012J0.47J 0.48 0.0092J ND<0.0049 ND<0.0049 0.12 0.62 ND<0.0049 0.039J 0.23 0.2 0.020J

ND<0.160 ND<0.016 ND<0.016 ND<0.016 ND<0.016 ND<0.016 0.031J ND<0.016 ND<0.016 ND<0.016 0.023J ND<0.0160.140J 0.11 0.0023J ND<0.0022 ND<0.0022 0.032J 0.24 ND<0.0022 0.008J 0.087 0.13 0.0086J

1.9 0.22 0.0044J ND<0.0031 ND<0.0031 0.053 0.29 ND<0.0031 0.022J 0.13 0.063 0.015J

0.210J 0.14 ND<0.0029 ND<0.0029 ND<0.0029 0.042J 0.53 ND<0.0029 0.038J 0.11 0.071 0.0072J0.89 0.4 0.0099J ND<0.0032 ND<0.0032 0.092 0.63 ND<0.0032 0.024J 0.25 0.062 0.014J0.6 0.33 0.0036J ND<0.0035 ND<0.0035 0.086 0.48 ND<0.0035 0.012J 0.22 0.053 0.0064J

0.220J 0.12 0.0024J ND<0.0022 ND<0.0022 0.036J 0.2 ND<0.0022 0.013J 0.17 0.020J 0.0034J0.290J 0.19 0.0041J ND<0.0026 ND<0.0026 0.053 0.57 ND<0.0026 0.042J 0.16 0.064 0.0097J0.480J ND<0.0044 0.0055J ND<0.0044 ND<0.0044 ND<0.0044 0.17 ND<0.0044 ND<0.0044 ND<0.0044 0.016J ND<0.00440.77 0.36 0.0077J ND<0.0025 ND<0.0025 0.085 0.45 ND<0.0025 0.014J 0.14 0.049J 0.0075J

ND<0.260 ND<0.026 ND<0.026 0.027J ND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026 0.25 ND<0.026

1.236 0.498 0.013 0.003 0.003 0.118 0.860 0.003 0.033 0.316 0.087 0.017


HA7 HA8 HA10



Page 12 of 16

Boring ID






PhenanthrenePyrene





GP1-0.5-1 GP1-2.5-3 GP1-5-5.5 GP1-10-10.5 GP1-15-15.5 GP1-20-20.5 DUP 4 GP1-24-24.5 GP2-0.5-1 GP2-2.5-3 GP2-5-5.5 DUP 5 GP2-10-10.5 GP2-15-15.5

0.5-1 2.5-3 5-5.5 10-10.5 15-15.5 20-20.5 20-20.5 24-24.5 0.5-1 2.5-3 5-5.5 5-5.5 10-10.5 15-15.55/11/2004 5/11/2004 5/11/2004 5/11/2004 5/11/2004 5/11/2004 5/11/2004 5/11/2004 5/11/2004 5/11/2004 5/11/2004 5/11/2004 5/11/2004 5/11/2004Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience

ND<0.032 ND<0.032 ND<0.032 ND<0.032 ND<0.640 ND<0.032 ND<0.032 ND<0.032 ND<0.032 ND<0.032 ND<0.032 ND<0.032 ND<0.032 ND<0.032ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.380 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019

2.2DJ 0.078 0.024J 0.062 36D 1.6D 0.0086J 0.0022J 0.52 0.68 0.019J 0.064 0.0029J 4.5D1.9 0.37 0.1 ND<0.0047 1.9 0.17 ND<0.0047 ND<0.0047 1.3D 3.8D ND<0.0047 0.88 ND<0.0047 0.1839D 1.4 0.46 0.58 73D 3.7D 0.007J ND<0.0049 5.6D 8.5D 0.22 0.76 ND<0.0049 12D0.77 0.13 0.086 0.033J 59D 2.3D 0.038J 0.035J 0.14 0.21 ND<0.016 0.037J ND<0.016 5.9D7.6D 0.11 0.076 0.12 67D 3.2D 0.030J 0.010J 1.3D 3.6D 0.11 0.25 0.0074J 7.1D15D 2.3D 0.25 0.54 17 0.68 0.0066J 0.0072J 3.0D 4.7D 0.17 0.73 ND<0.0031 0.57

23D 1.7D 0.2 0.42 21D 0.84 ND<0.0029 ND<0.0029 3.5D 3.6D 0.13 0.53 ND<0.0029 2.9D13D 1.3D 0.049J 0.35 16 0.58 ND<0.0032 ND<0.0032 3.6D 5.1D 0.23 0.95 ND<0.0032 1.1D5.0D 0.56 ND<0.0035 0.24 12 0.42 ND<0.0035 ND<0.0035 2.8D 3.7D 0.1 0.58 ND<0.0035 16.2D 0.29 ND<0.0022 0.1 9.4 0.25 ND<0.0022 ND<0.0022 1.5D 1.6D 0.018J 0.15 ND<0.0022 0.4323D 1.6D 0.28 0.37 16DJ 0.76 ND<0.0026 ND<0.0026 3.5D 3.8D 0.11 0.52 ND<0.0026 2.2D

ND<0.0044 ND<0.0044 ND<0.0044 ND<0.0044 ND<0.088 ND<0.0044 ND<0.0044 ND<0.0044 ND<0.0044 ND<0.0044 ND<0.0044 ND<0.0044 ND<0.0044 ND<0.00445.1D 0.22 ND<0.0025 ND<0.0025 6.2 0.095 ND<0.0025 ND<0.0025 2.1D 3.8D ND<0.0025 0.56 ND<0.0025 0.15

ND<0.026 ND<0.026 ND<0.026 ND<0.026 250D 9.8 0.25 0.33 ND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026

17.161 1.594 0.073 0.431 21.035 0.749 0.003 0.003 4.626 6.409 0.257 1.138 0.003 1.571


GP1 GP2



Page 13 of 16

Boring ID






PhenanthrenePyrene





GP3-0.5-1 GP3-2.5-3 GP3-5-5.5 GP3-10-10.5 GP3-15-15.5 GP3-20-20.5 GP3-23.5-24 GP4-0.5-1 GP4-2.5-3 GP4-5-5.5 GP4-10-10.5 GP4-15-15.5 GP4-20-20.5 GP4-23.5-24

0.5-1 2.5-3 5-5.5 10-10.5 15-15.5 20-20.5 23.5-24 0.5-1 2.5-3 5-5.5 10-10.5 15-15.5 20-20.5 23.5-245/11/2004 5/11/2004 5/11/2004 5/11/2004 5/11/2004 5/11/2004 5/11/2004 5/11/2004 5/11/2004 5/11/2004 5/11/2004 5/11/2004 5/11/2004 5/11/2004Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience

ND<0.032 ND<0.032 ND<0.032 ND<0.032 ND<0.032 8.6 ND<0.032 ND<0.032 ND<0.032 ND<0.032 ND<0.032 ND<0.320 ND<0.032 ND<0.032ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.190 ND<0.019 ND<0.019

0.017J ND<0.0019 ND<0.0019 ND<0.0019 0.012J 14D 0.055 0.06 0.17 0.48 0.45 40D 0.014J ND<0.00190.044J ND<0.0047 ND<0.0047 ND<0.0047 ND<0.0047 0.85 ND<0.0047 0.38 0.34 0.42 0.5 1.2 ND<0.0047 ND<0.00470.16 0.0053J ND<0.0049 ND<0.0049 0.017J 29D 0.066 1 2.8D 6.6D 3.9D 84D 0.018J ND<0.0049

0.020J ND<0.016 ND<0.016 ND<0.016 ND<0.016 18D 0.072 0.13 0.13 0.091 0.13 58D 0.021J ND<0.0160.067 0.0036J ND<0.0022 ND<0.0022 0.0023J 19D 0.016J 0.16 0.14 0.84 0.71 87D 0.031J 0.0052J0.069 ND<0.0031 ND<0.0031 ND<0.0031 ND<0.0031 7.8D 0.017J 0.84 1.3D 3.3D 2.6D 18D 0.011J 0.0033J

0.11 0.0033J ND<0.0029 ND<0.0029 ND<0.0029 9.0D 0.0061D 0.91 1.6D 3.5D 2.6D 24D ND<0.0029 ND<0.00290.13 ND<0.0032 ND<0.0032 ND<0.0032 ND<0.0032 5.5D 0.004J 0.62 0.76 3.0D 2.8D 14D ND<0.0032 ND<0.00320.08 ND<0.0035 ND<0.0035 ND<0.0035 ND<0.0035 4.4D ND<0.0035 0.47 0.49 1.7 1.8 7.8 ND<0.0035 ND<0.0035

0.030J ND<0.0022 ND<0.0022 ND<0.0022 ND<0.0022 2.7D ND<0.0022 0.31 0.32 0.99 0.85 6 ND<0.0022 ND<0.00220.095 ND<0.0026 ND<0.0026 ND<0.0026 ND<0.0026 6.9D ND<0.0026 0.85 1.1D 3.2D 2.4D 19D ND<0.0026 ND<0.0026

ND<0.0044 ND<0.0044 ND<0.0044 ND<0.0044 ND<0.0044 ND<0.0044 ND<0.0044 ND<0.0044 ND<0.0044 ND<0.0044 ND<0.0044 ND<0.044 ND<0.0044 ND<0.00440.039J 0.003J ND<0.0025 ND<0.0025 ND<0.0025 2.0D ND<0.0025 0.22 0.19 1.2D 0.67 5.2 ND<0.0025 ND<0.0025

ND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026 0.16 ND<0.026 320D 0.084 0.16

0.158 0.003 0.003 0.003 0.003 7.380 0.006 0.820 1.032 3.772 3.417 18.497 0.003 0.003


GP4GP3



Page 14 of 16

Boring ID






PhenanthrenePyrene





TPG-1-2 TPG-1-5 TPG-1-10 TPG-1-16 TPG-1-19.5 TPG-1-23.5 TPG-2-2 TPG-2-5 TPG-2-10 TPG-2-15 TPG-2-20 TPG-2-24.5

2 5 10 16 19.5 23.5 2 5 10 15 20 24.52/13/08 2/13/08 2/13/08 2/13/08 2/13/08 2/13/08 2/13/08 2/13/08 2/13/08 2/13/08 2/13/08 2/13/08

Test America Test America Test America Test America Test America Test America Test America Test America Test America Test America Test America Test America

0.0013 J 0.02 ND<0.00025 ND<0.00025 ND<0.00025 0.0089 0.065 0.67 0.45 0.024 0.0013 J 0.00036 J0.00043 J 0.0014 J ND<0.00023 ND<0.00023 ND<0.00023 0.011 0.012 J 0.12 0.015 J 0.031 0.0022 J 0.00083 J0.0016 J 0.022 ND<0.00011 0.00013 J B 0.00013 J B ND<0.00011 0.11 1.1 0.082 J 0.079 0.0006 J B 0.0002 J B

0.0074 0.033 ND<0.00043 0.00043 J ND<0.00043 ND<0.00043 0.23 1.5 0.28 0.028 ND<0.00043 ND<0.00043 0.012 0.081 0.00023 J 0.00099 J 0.0002 J 0.0002 J 0.55 5.9 0.6 0.1 0.0005 J 0.00036 J

0.00056 J 0.0055 ND<0.00024 ND<0.00023 ND<0.00023 0.013 0.032 0.3 0.092 J 0.068 0.00026 J ND<0.00023 0.0061 0.018 0.0004 J B 0.00046 J B 0.0004 J B 0.0097 0.29 2.6 0.08 J 0.12 0.00056 J B 0.00036 J B0.013 0.12 0.00027 J 0.0011 J 0.0002 J ND<0.00012 0.63 6.5 1.2 0.1 0.0006 J 0.00046 J

0.01 0.098 0.00053 0.0012 0.00076 0.00093 0.57 7 0.6 0.058 0.0006 0.00060.0073 0.086 ND<0.0003 0.00059 ND<0.0003 ND<0.0003 0.61 5.9 0.75 0.055 ND<0.0003 ND<0.00030.016 0.1 ND<0.00043 0.00089 ND<0.00043 ND<0.00043 1 8.5 0.77 0.056 0.00063 0.00043

ND<0.00015 0.032 ND<0.00015 0.00026 ND<0.00015 ND<0.00015 ND<0.00076 1.8 0.32 0.022 ND<0.00015 ND<0.000150.0083 0.083 0.00023 0.00069 0.00017 0.00026 0.45 4.2 0.53 0.052 0.00036 0.000260.0012 0.021 ND<0.00037 ND<0.00037 ND<0.00037 ND<0.00037 0.052 0.56 0.09 0.008 ND<0.00037 ND<0.00037 0.0061 0.034 ND<0.00037 ND<0.00037 ND<0.00037 ND<0.00037 0.23 1.6 0.27 0.025 ND<0.00037 ND<0.00037

0.00099 J B 0.0024 J B 0.00043 J B 0.0003 J B 0.00079 J B 0.0042 J 0.02 J 0.33 0.011 J 0.026 0.00073 J B 0.00093 J B0.0110 0.1204 0.0003 0.0009 0.0003 0.0004 0.8122 8.0224 0.9819 0.0743 0.0004 0.0003


TPG-1 TPG-2



Page 15 of 16

Boring ID






PhenanthrenePyrene





TPG-3-2 TPG-3-5 TPG-3-12 TPG-3-15 TPG-3-20 TPG-3-24.5 TPG-4-2 TPG-4-5 TPG-4-10 TPG-4-15 TPG-4-20 TPG-4-24.5

2 5 12 15 20 24.5 2 5 10 15 20 24.52/12/08 2/12/08 2/12/08 2/12/08 2/12/08 2/12/08 2/13/08 2/13/08 2/13/08 2/13/08 2/13/08 2/13/08

Test America Test America Test America Test America Test America Test America Test America Test America Test America Test America Test America Test America

0.066 0.00047 J 4 0.0028 J 0.0091 0.022 0.049 0.0058 ND<0.00025 0.022 0.37 0.00033 J0.0031 J ND<0.00023 3.2 0.0015 J 0.0041 J 0.023 0.00097 J ND<0.00023 ND<0.00023 0.018 0.19 0.004 J

0.1 0.00033 J 5 0.0026 J 0.017 0.031 0.09 0.0027 J 0.00012 J 0.056 0.54 0.00017 J B0.14 0.00083 J 0.47 0.0013 J 0.0036 J ND<0.00043 0.071 0.0051 ND<0.00043 0.001 J 0.051 ND<0.00043 1.1 0.0023 J 4.1 0.0033 J 0.014 0.015 0.48 0.012 0.00039 J 0.046 0.6 0.0003 J

0.023 0.00027 J 7.8 0.003 J 0.0093 0.054 0.01 0.001 J ND<0.00023 0.059 0.65 ND<0.00023 0.048 0.0006 J 12 0.005 0.016 0.0048 J 0.16 0.0029 J 0.00033 J B 0.13 1.1 0.00046 J B1.2 0.0028 J 5.1 0.0042 J 0.021 0.011 0.48 0.016 0.00054 J 0.038 0.56 0.00027 J

1 0.0015 2.7 0.0033 0.01 0.0011 0.45 0.019 0.0013 0.014 0.3 0.00030.59 0.0017 1.5 0.0031 0.0099 0.0009 0.3 0.018 0.00055 0.0056 0.19 ND<0.00030.55 0.0034 1.6 0.0031 0.0085 0.00076 0.41 0.024 ND<0.00043 0.0057 0.21 ND<0.000430.25 ND<0.00015 0.39 0.0015 0.0034 0.0003 0.12 0.0064 ND<0.00015 0.0021 0.097 ND<0.000150.71 0.0021 2.4 0.0026 0.0091 0.00096 0.31 0.013 0.0005 0.0055 0.25 0.000230.056 ND<0.00037 0.12 0.0012 ND<0.00037 ND<0.00037 0.029 0.0018 ND<0.00037 0.00041 0.028 ND<0.00037 0.16 0.00077 0.44 0.0013 0.003 ND<0.00037 0.08 0.0052 ND<0.00037 0.0013 0.063 ND<0.00037

0.0029 J 0.00063 J 8.4 0.0054 0.0037 J 0.003 J 0.0037 J 0.00042 J B 0.00046 J B 0.065 1.2 0.0006 J B0.8121 0.0024 2.0778 0.0045 0.0125 0.0012 0.4190 0.0242 0.0008 0.0081 0.2690 0.0003


TPG-3 TPG-4



Page 16 of 16

Boring ID






PhenanthrenePyrene





TPG-5-2 TPG-5-5 TPG-5-10 TPG-5-15 TPG-5-20 TPG-5-24.5

2 5 10 15 20 24.52/13/08 2/13/08 2/13/08 2/13/08 2/13/08 2/13/08

Test America Test America Test America Test America Test America Test America

0.00052 J 0.0011 J 0.001 J 0.0013 J 0.00043 J 0.00039 JND<0.00046 0.0014 J ND<0.00023 ND<0.00047 ND<0.00023 ND<0.00023

0.00063 J 0.0051 0.0014 J 0.0017 J 0.00059 J 0.00048 J0.0016 J 0.0014 J 0.0014 J 0.0018 J ND<0.00043 0.00051 J0.0044 J 0.0068 0.0051 0.0071 J 0.0012 J 0.0003 J

ND<0.00047 0.0036 J 0.00087 J 0.00096 J 0.00056 J ND<0.00023 0.0038 J 0.0017 J 0.0065 0.0062 J 0.00056 J B ND<0.00016 0.0051 J 0.0066 0.0054 0.0076 J 0.0012 J 0.00045 J

0.0033 0.0019 0.0038 0.0067 0.00093 0.0020.0018 0.0022 0.002 0.0032 ND<0.0003 0.000640.0035 0.0025 0.003 0.0051 0.00053 ND<0.00043

ND<0.0003 0.00099 ND<0.00015 ND<0.00031 ND<0.00015 ND<0.000150.0049 0.0028 0.0028 0.0047 0.00086 0.00064

ND<0.00074 ND<0.00037 0.00045 ND<0.00075 ND<0.00037 ND<0.00037 0.001 0.0011 0.0011 0.0015 ND<0.00037 0.00041

0.00078 J B 0.0003 J B 0.00096 J B 0.0026 J B 0.00069 J B 0.00065 J B0.0028 0.0029 0.0030 0.0047 0.0004 0.0010


TPG-5

Table 2-1BSummary of Metals Concentrations in Soil Samples


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60107060 or 6010B1 6010 6010 6010

7196/7196A or 71992 6010 6010 6010 6010 7571 6010 6010 7740 6010 7841 6010 6010

Location IDYear

SampledSample Depth

(feet bgs)MT-408-8-1 1986 0 NA 28* NA NA NA NA NA NA NA 360* 1* NA NA NA NA NA NA NA

DSS-WAT1-1 1991 0 2.6 0.84 36.7 ND<0.2 0.3 ND<11.4 48.7 6.7 13.6 ND<4.1 0.22 ND<0.5 30.2 ND<0.18 ND<0.2 ND<0.21 24.3 28.7DSS-WAT1-2 1991 0 3.7 8.79 146 ND<0.2 0.7 ND<11.1 43.5 9.6 30.4 83.3 0.11 ND<0.4 51.9 ND<0.18 ND<0.2 ND<0.2 35.8 118DSS-WAT1-3 1991 0 3.2 10.3 88.9 0.2 1.2 24.8 28 7.7 38.7 106 0.2 0.5 28 ND<0.18 ND<0.2 ND<0.2 27.3 138DSS-WAT1-4 1991 0 4.4 2.15 55.3 ND<0.2 0.5 ND<12.1 74.4 10 16.8 26.4 ND<0.07 ND<0.5 47.5 ND<0.19 ND<0.2 ND<0.22 37.1 55.1DSS-WAT1-5 1991 0 ND<1.7 4.63 95.5 ND<0.2 0.9 ND<10.7 31 8 21.8 44.9 0.06 ND<0.4 32.8 0.2 ND<0.2 ND<0.19 30.9 187DSS-WAT1-5 1991 0 DUP 5.9 5.33 129 0.3 1.1 ND<10.8 50.3 9.3 32.7 154 0.13 ND<0.4 37.4 ND<0.17 ND<0.2 ND<0.19 43.3 164

B-WAT1-1 1991 3.5 2.5 2.79 114 0.5 0.7 ND<11.6 44.2 16.1 16 5.4 ND<0.07 ND<0.5 36 ND<0.19 0.4 ND<0.21 45.8 42.510 2.9 1.67 72.4 ND<0.2 0.5 ND<11.7 63.2 12.4 9.5 ND<4.2 ND<0.07 ND<0.5 63.2 ND<0.19 0.4 ND<0.21 27 30.715 4.1 2.91 114 ND<0.2 0.7 ND<11.4 56.2 14.5 17.9 ND<4.1 ND<0.07 ND<0.5 120 ND<0.18 0.3 ND<0.2 34.2 36.5

MW-WAT1-1 1991 3 2.9 2.84 150 0.6 0.6 ND<11.6 40.6 11.9 16.9 7.1 ND<0.07 0.9 33.3 ND<0.19 ND<0.2 ND<0.21 55.5 40.38 5.9 2.69 129 0.5 0.5 ND<11.7 45.1 13 14.5 6.7 ND<0.07 ND<0.5 31.3 ND<0.19 ND<0.2 0.21 53.6 36.412 3.3 2.12 140 0.2 0.3 ND<11.5 66.1 13.5 14.7 ND<4.1 ND<0.07 ND<0.5 87.7 ND<0.18 ND<0.2 0.21 31.4 35.718 2.3 2.52 83.7 ND<0.2 0.3 ND<11.3 66.6 9.7 12.8 ND<4.1 ND<0.07 ND<0.5 69 ND<0.18 ND<0.2 ND<0.2 24.2 25.520 5.5 1.94 495 ND<0.2 0.5 ND<11.1 52.4 10.6 23.9 4.3 ND<0.07 ND<0.4 79.7 ND<0.18 ND<0.2 ND<0.2 39.5 48.4

MW-WAT1-2 1991 4 3.9 4.77 165 ND<0.2 0.9 ND<11.6 34 11.5 17.5 51.7 0.07 ND<0.5 131 ND<0.19 0.3 ND<0.21 174 62.75 6.3 3.14 175 0.4 0.8 ND<11.4 63.9 12.6 19.7 41.9 ND<0.07 ND<0.5 67.9 ND<0.18 0.4 ND<0.21 53.1 53.810 3.5 2.25 86.8 0.3 0.9 ND<11.4 82.6 10 12.9 5.2 ND<0.07 ND<0.5 63.5 ND<0.18 0.5 ND<0.2 41 32.4

11.5 4.3 3.05 104 0.4 0.6 ND<11.4 82.4 11 16.9 ND<4.1 ND<0.07 ND<0.5 54.1 ND<0.18 0.2 ND<0.21 37.9 36.913 5.4 1.61 77.4 0.2 0.9 ND<11.7 92 11.4 12.2 5.2 ND<0.07 ND<0.5 82 ND<0.19 0.4 ND<0.21 40 34

13 DUP 3.5 1.42 63.7 ND<0.2 0.5 ND<11.4 66.6 9.5 11.7 ND<4.1 ND<0.07 ND<0.5 69.1 ND<0.18 ND<0.2 ND<0.21 33.4 28.615 4 1.94 198 ND<0.2 0.6 ND<11.5 64.5 11.5 57.4 5 ND<0.07 ND<0.5 89.7 ND<0.18 ND<0.2 ND<0.21 28.6 55.3

MW-WAT1-3 1991 3.5 2.6 2.26 156 0.3 0.8 ND<11.6 33.2 14.3 15.7 7 ND<0.07 ND<0.5 27.7 ND<0.18 0.3 ND<0.21 45.4 44.210 3.3 2.81 141 ND<0.2 0.6 ND<11.8 58.1 10.6 21.4 ND<4.3 0.08 0.7 72.9 ND<0.19 0.5 ND<0.21 31.1 46.213 5.1 1.44 151 ND<0.2 0.8 ND<10.9 67.7 15.6 17.2 ND<4 ND<0.07 ND<0.4 119 ND<0.18 0.5 ND<0.2 41.2 40.4

13 DUP ND<1.8 1.75 97.9 ND<0.2 0.6 ND<12.7 66.9 10.6 12.5 ND<4.1 ND<0.07 ND<0.5 93.7 ND<0.18 0.3 ND<0.21 26 31.415 3.5 1.33 93.7 ND<0.2 0.6 ND<11.3 75 9.9 14 ND<4.1 ND<0.07 ND<0.5 83.4 ND<0.18 0.6 ND<0.2 28.2 31.518 4 1.71 70 ND<0.2 0.5 ND<11.3 55.3 8.7 8.8 ND<4.1 ND<0.07 ND<0.5 63.2 ND<0.18 0.4 ND<0.2 21.6 25.420 2.4 3.74 57.6 ND<0.2 0.5 ND<11.6 37.9 5.3 6.9 ND<4.2 ND<0.07 ND<0.5 50.4 ND<0.19 0.3 ND<0.21 18.4 21.223 4.8 2.01 115 ND<0.2 0.5 ND<11.3 92.3 9.5 12.1 ND<4.1 ND<0.07 ND<0.5 86 ND<0.18 0.4 ND<0.2 27.1 2925 4.6 2.14 91.6 ND<0.2 0.6 ND<11.4 74.6 10.6 13.6 ND<4.1 ND<0.07 ND<0.5 82.9 ND<0.18 0.3 ND<0.21 29.3 32.5

SS-WAT1-1 2001 1 NA 2.7 NA NA NA ND<0.2 NA NA NA NA NA NA NA NA NA NA NA NA2.5 NA 1.7 NA NA NA ND<0.2 NA NA NA NA NA NA NA NA NA NA NA NA

SS-WAT1-2 2001 1 NA 10 NA NA NA ND<0.2 NA NA NA NA NA NA NA NA NA NA NA NA1 DUP NA 5.7 NA NA NA ND<0.2 NA NA NA NA NA NA NA NA NA NA NA NA

2.5 NA 5.9 NA NA NA ND<0.2 NA NA NA NA NA NA NA NA NA NA NA NASS-WAT1-3 2001 1 NA 7.2 NA NA NA ND<0.2 NA NA NA NA NA NA NA NA NA NA NA NA

2.5 NA 2.9 NA NA NA ND<0.2 NA NA NA NA NA NA NA NA NA NA NA NASS-WAT1-4 2001 1 NA 4.1 NA NA NA ND<0.2 NA NA NA NA NA NA NA NA NA NA NA NA

2.5 NA 4.7 NA NA NA ND<0.2 NA NA NA NA NA NA NA NA NA NA NA NA

Analyte

USEPA Method Number



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60107060 or 6010B1 6010 6010 6010

7196/7196A or 71992 6010 6010 6010 6010 7571 6010 6010 7740 6010 7841 6010 6010

Location IDYear

SampledSample Depth

(feet bgs)

Analyte

USEPA Method Number




SS-WAT1-8 2001 1 NA 3 NA NA NA ND<0.2 NA NA NA NA NA NA NA NA NA NA NA NA2.5 NA 2.7 NA NA NA ND<0.2 NA NA NA NA NA NA NA NA NA NA NA NA

SS-WAT1-9 2001 1 NA 8 NA NA NA ND<0.2 NA NA NA NA NA NA NA NA NA NA NA NA2.5 NA 4.4 NA NA NA ND<0.2 NA NA NA NA NA NA NA NA NA NA NA NA

B-WAT1-2 2001 6.5 NA ND<1 NA NA NA ND<0.2 NA NA NA NA NA NA NA NA NA NA NA NA10 NA ND<1 NA NA NA ND<0.2 NA NA NA NA NA NA NA NA NA NA NA NA15 NA ND<1 NA NA NA ND<0.2 NA NA NA NA NA NA NA NA NA NA NA NA

B-WAT1-3 2001 6.5 NA ND<1 NA NA NA ND<0.2 NA NA NA NA NA NA NA NA NA NA NA NA10 NA ND<1 NA NA NA ND<0.2 NA NA NA NA NA NA NA NA NA NA NA NA

10 DUP NA 1.6 NA NA NA ND<0.2 NA NA NA NA NA NA NA NA NA NA NA NA15 NA 1.6 NA NA NA ND<0.2 NA NA NA NA NA NA NA NA NA NA NA NA

MW-WAT1-4 2001 6.5 NA 1.4 NA NA NA ND<0.2 NA NA NA NA NA NA NA NA NA NA NA NA10 NA 1.6 NA NA NA ND<0.2 NA NA NA NA NA NA NA NA NA NA NA NA15 NA 1.1 NA NA NA ND<0.2 NA NA NA NA NA NA NA NA NA NA NA NA20 NA 3.3 NA NA NA ND<0.2 NA NA NA NA NA NA NA NA NA NA NA NA

MW-WAT1-5 2001 6.5 NA 3.4 NA NA NA ND<0.2 NA NA NA NA NA NA NA NA NA NA NA NA10 NA 1.9 NA NA NA ND<0.2 NA NA NA NA NA NA NA NA NA NA NA NA15 NA 1.5 NA NA NA ND<0.2 NA NA NA NA NA NA NA NA NA NA NA NA20 NA 2.2 NA NA NA ND<0.2 NA NA NA NA NA NA NA NA NA NA NA NA

20 DUP NA 1.2 NA NA NA ND<0.2 NA NA NA NA NA NA NA NA NA NA NA NAHA9 2004 0-0.5 NA NA NA NA NA 0.22 NA NA NA NA NA NA NA NA NA NA NA NA

0-0.5 DUP NA NA NA NA NA 0.17 NA NA NA NA NA NA NA NA NA NA NA NA1-1..5 NA NA NA NA NA 0.26 NA NA NA NA NA NA NA NA NA NA NA NA

TPG-1 2008 2 ND (0.053) 4.4 130 0.75 0.95 33 NA 6.7 18 6 ND (0.0010) 0.61 J B 26 ND (0.11) 0.071 J ND (0.075) 38 505 ND (0.052) 5.1 130 0.59 0.34 J 31 NA 8.2 19 7.8 0.056 0.55 J 29 0.28 J 0.13 J 0.095 J 35 10010 ND (0.053) 2.4 86 0.39 J 0.10 J 25 NA 6.2 8.8 3.8 0.029 J 0.16 J 18 ND (0.11) 0.030 J ND (0.075) 33 2116 ND (0.050) 2.6 95 0.40 J 0.17 J 45 NA 8.3 9.6 4 0.025 J 0.46 J 38 ND (0.10) 0.043 J ND (0.071) 30 26

19.5 ND (0.053) 3.2 140 0.34 J 0.19 J 55 NA 10 13 3.2 0.039 J ND (0.044) 71 ND (0.11) 0.045 J ND (0.075) 29 3623.5 ND (0.050) 1.4 140 0.35 J 0.19 J 69 NA 11 18 4.2 0.077 ND (0.041) 110 ND (0.10) 0.048 J ND (0.071) 30 44

TPG-2 2008 2 ND (0.050) 7.5 97 0.44 J 1.1 35 NA 7.1 24 39 0.096 0.29 J B 38 ND (0.11) 0.12 J ND (0.072) 26 1205 ND (0.052) 5.9 160 0.59 0.9 32 NA 6.7 16 38 0.21 0.41 J B 38 ND (0.11) 0.10 J ND (0.075) 30 5510 ND (0.055) 2.1 54 0.50 J 0.82 39 NA 8.1 8.3 2.7 0.037 J 0.24 J B 43 ND (0.11) 0.031 J ND (0.078) 29 2415 ND (0.053) 2.7 88 0.48 J 0.64 43 NA 7.1 9.8 14 0.055 0.84 J B 39 ND (0.11) 0.046 J ND (0.076) 27 2720 ND (0.052) 2.6 70 0.35 J 0.55 41 NA 7.5 8.1 2.3 0.031 J 0.11 J B 65 ND (0.11) 0.025 J ND (0.074) 21 21

24.5 ND (0.053) 3.1 130 0.74 1.2 84 NA 11 19 2.7 0.034 J 0.31 J B 110 ND (0.11) 0.030 J ND (0.075) 45 36



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60107060 or 6010B1 6010 6010 6010

7196/7196A or 71992 6010 6010 6010 6010 7571 6010 6010 7740 6010 7841 6010 6010

Location IDYear

SampledSample Depth

(feet bgs)

Analyte

USEPA Method Number

TPG-3 2008 2 ND (0.050) 3.6 95 0.38 J 0.23 J 26 NA 6.7 11 4.2 0.09 0.16 J 22 0.42 J 0.058 J ND (0.072) 31 325 ND (0.051) 3.3 100 0.54 0.16 J 32 NA 6.4 12 4.8 0.035 J 0.44 J 25 ND (0.11) 0.058 J ND (0.073) 40 2912 ND (0.053) 2.2 110 0.27 J 0.19 J 40 NA 8.2 11 3.4 0.045 J 0.44 J 65 ND (0.11) 0.066 J ND (0.076) 22 2215 ND (0.054) 3 130 0.24 J 0.16 J 78 NA 8.6 13 3.7 0.048 J 0.12 J 84 ND (0.11) 0.057 J ND (0.077) 30 2220 ND (0.055) 1.8 71 0.21 J 0.11 J 54 NA 8.6 11 2 0.029 J ND (0.045) 65 ND (0.12) 0.053 J ND (0.079) 31 21

24.5 ND (0.051) 1.7 150 0.43 J 0.17 J 41 NA 12 23 4.8 0.091 ND (0.042) 100 ND (0.11) 0.049 J ND (0.073) 28 48TPG-4 2008 2 ND (0.050) 7.5 100 0.67 0.9 55 NA 9.9 16 11 0.095 0.38 J B 45 ND (0.10) 0.048 J ND (0.071) 35 38

5 ND (0.050) 3.6 110 0.75 0.85 38 NA 6.2 12 4.7 0.021 J 0.38 J B 25 ND (0.11) 0.019 J ND (0.072) 45 3310 ND (0.051) 2.8 58 0.48 J 0.7 38 NA 6.4 6.8 2.4 0.029 J 0.15 J B 39 ND (0.11) 0.020 J ND (0.073) 25 2215 ND (0.051) 1.8 59 0.33 J 0.51 45 NA 6.6 6.9 2 0.055 0.18 J B 58 ND (0.11) 0.025 J ND (0.073) 21 2020 ND (0.052) 3.7 170 0.59 0.92 75 NA 10 20 2.8 0.062 3.1 B 120 ND (0.11) 0.069 J ND (0.074) 34 27

24.5 ND (0.051) 2.4 98 0.45 J 0.74 59 NA 10 13 2.4 0.28 0.27 J B 77 ND (0.11) 0.044 J ND (0.073) 34 27TPG-5 2008 2 ND (0.053) 2.6 110 0.56 0.69 26 NA 7.1 15 4.3 0.021 J 0.90 J B 21 ND (0.11) 0.041 J 0.18 J B 33 29

5 ND (0.052) 3 110 0.75 0.72 34 NA 10 11 4 0.038 J 0.43 J B 25 ND (0.11) 0.035 J ND (0.074) 39 2510 ND (0.052) 3.2 130 0.72 0.98 91 NA 7.4 12 3.5 0.041 J 1.5 B 72 ND (0.11) 0.045 J ND (0.075) 34 3215 ND (0.054) 3.1 110 0.61 0.89 70 NA 9.2 14 2.9 ND (0.00099) 1.7 B 66 ND (0.11) 0.052 J ND (0.077) 40 2820 ND (0.053) 4.2 120 0.62 1 59 NA 9.5 19 3.6 0.042 J 0.18 J B 110 ND (0.11) 0.046 J ND (0.076) 32 38

24.5 ND (0.054) 2.3 83 0.41 J 0.64 49 NA 7.3 10 2.6 0.036 J 0.072 J B 61 ND (0.11) 0.031 J ND (0.077) 24 26

Notes:All results are presented in milligrams per kilogram (mg/kg)."ND<" indicates the constituent was not detected at or above the laboratory reporting limit or method detection limit.bgs = below ground surfaceNA = not analyzedUSEPA = United States Environmental Protection Agency(1) 1991 PEA arsenic samples analyzed by USEPA Method 7060; 2001 SI arsenic samples analyzed by USEPA Method 6010B.(2) 1991 PEA Cr6 samples analyzed by USEPA Method 7196; 2001 SI Cr6 samples analyzed by USEPA Method 7196A; 2004 Cr6 samples analyzed by USEPA Method 7199.* analytical method not knownB = estimated value; analyte detected in the sample and the assocaited method blank. Analyte was detected at a concentration less than 10 times the concentration detected in method blank.J = estimated value; analyte detected at a concentration less than the reporting limit and greater than or equal to the method detection limit

Table 2-1CSummary of TPH and TRPH Concentrations in Soil Samples


Page 1 of 2

TPHg TPHd TPHmoDSS-1-WAT1-1 1991 0 (surface soil) 1.5 ND<110 NA 84.9DSS-1-WAT1-2 1991 0 (surface soil) 8.1 ND<110 NA 35.6DSS-1-WAT1-3 1991 0 (surface soil) 1.9 ND<110 NA 66.5DSS-1-WAT1-4 1991 0 (surface soil) ND<1.2 ND<24 NA 38.6DSS-1-WAT1-5 1991 0 (surface soil) 2.2 ND<110 NA 91.2

B-WAT1-1 1991 3.5 2.7 ND<12 NA ND<1.910 ND<1.2 ND<12 NA ND<1.915 ND<1.1 ND<11 NA ND<1.9

MW-WAT1-1 1991 3 ND<1.2 ND<12 NA ND<1.98 ND<1.2 ND<12 NA ND<1.612 ND<1.2 ND<12 NA ND<1.918 ND<1.1 ND<11 NA ND<1.620 ND<1.1 ND<11 NA ND<1.8

MW-WAT1-2 1991 4 5.8 ND<120 NA 1415 3.8 ND<110 NA 12410 ND<1.1 ND<11 NA ND<1.9

11.5 ND<1.1 ND<11 NA 2.513 21 600 NA 19.4

13-DUP 200 1,200 NA 27.115 1.9 ND<12 NA ND<1.9

MW-WAT1-3 1991 3.5 ND<1.2 ND<12 NA ND<1.910 21 ND<120 NA 18.813 3,000 4,400 NA 67315 3,500 2,500 NA 31618 120 210 NA 29620 1.6 ND<12 NA ND<1.923 1.7 ND<11 NA ND<1.925 ND<1.1 ND<11 NA ND<1.9

SS-WAT1-1 2001 1 ND<1 4.7 ND<50 NA2.5 ND<1 2.8 ND<50 NA

SS-WAT1-2 2001 1 ND<1 12 80 NA2.5 ND<1 7.9 71 NA

SS-WAT1-3 2001 1 ND<1 15 140 NA2.5 ND<1 9.1 120 NA

SS-WAT1-4 2001 1 ND<1 36 150 NA2.5 ND<1 750 660 NA

SS-WAT1-5 2001 1 ND<1 860 2,000 NA2.5 ND<1 2.3 ND<50 NA

SS-WAT1-6 2001 1 ND<1 700 1,500 NA2.5 ND<1 270 530 NA

SS-WAT1-7 2001 1 ND<1 50 400 NA2.5 ND<1 6.4 ND<50 NA

SS-WAT1-8 2001 1 ND<1 210 2,300 NA2.5 ND<1 4.8 55 NA


B-WAT1-2 2001 6.5 ND<1 ND<1 ND<50 NA10 ND<1 ND<1 ND<50 NA15 ND<1 ND<1 ND<50 NA

B-WAT1-3 2001 6.5 ND<1 1.5 ND<50 NA10 ND<1 1.3 ND<50 NA15 ND<1 ND<1 ND<50 NA

MW-WAT1-4 2001 6.5 ND<1 ND<1 ND<50 NA10 ND<1 ND<1 ND<50 NA15 ND<1 ND<1 ND<50 NA20 ND<1 350 450 NA

MW-WAT1-5 2001 6.5 ND<1 47 ND<50 NA10 ND<1 ND<1 ND<50 NA15 ND<1 ND<1 ND<50 NA20 ND<1 ND<1 ND<50 NA

GP1 2004 2.5-3 ND<0.22 2,100 4,200 NA5-5.5 ND<0.20 66 120 NA

10-10.5 490 400 1,500 NA15-15.5 5,300 14,000 9,500 NA20-20.5 0.8 1,500 2,500 NA

20-20.5 DUP 0.53 ND<5.0 ND<25 NA24-24.5 ND<0.69 ND<5.0 ND<25 NA

TRPHLocation ID Total Petroleum HydrocarbonsYear Sampled

Sample Depth(feet bgs)

Table 2-1CSummary of TPH and TRPH Concentrations in Soil Samples


Page 2 of 2

TPHg TPHd TPHmo TRPHLocation ID Total Petroleum HydrocarbonsYear Sampled

Sample Depth(feet bgs)

GP2 2004 2.5-3 ND<0.50 98 2,700 NA5-5.5 ND<0.50 160 440 NA

5-5.5 DUP ND<0.50 270 930 NA10-10.5 ND<0.26 71 190 NA15-15.5 ND<0.30 620 640 NA

GP3 2004 2.5-3 ND<0.50 ND<5.0 ND<25 NA5-5.5 ND<0.50 ND<5.0 ND<25 NA

10-10.5 ND<0.24 ND<5.0 ND<25 NA15-15.5 ND<0.33 ND<5.0 ND<25 NA20-20.5 ND<0.20 840 950 NA23.5-24 ND<0.41 ND<5.0 ND<25 NA

GP4 2004 2.5-3 ND<0.50 150 210 NA5-5.5 ND<0.33 180 260 NA

10-10.5 ND<0.21 190 300 NA15-15.5 1,300 8,600 5,200 NA20-20.5 ND<0.28 ND<5.0 ND<25 NA23.5-24 0.35 ND<5.0 ND<25 NA

TPG-1 2008 2-2.5 0.038 J B 5.5 15 J NA5-5.5 0.035 J B 14 41 J NA

10-10.5 0.033 J B 0.74 J ND<9.2 NA16-16.5 0.057 J B 1 ND<9.2 NA19.5-20 0.041 J B 0.47 J ND<9.2 NA23.5-24 0.13 J B 0.84 J ND<9.1 NA

TPG-2 2008 2-2.5 0.041 J B 230 620 NA5-5.5 0.25 B 560 1,200 NA

10-10.5 0.027 J B 320 510 NA15-15.5 0.093 J B 9.2 17 J NA20-20.5 0.030 J B 0.63 J ND<9.2 NA24.5-25 0.037 J B 0.75 J ND<9.2 NA

TPG-3 2008 2-2.5 0.044 J B 180 300 NA5-5.5 0.044 J B 1.3 ND<9.2 NA

12-12.5 43 B J 1,200 910 NA15-15.5 0.082 J B 2.7 ND<9.2 NA20-20.5 0.088 J B 3.9 ND<9.2 NA24.5-25 0.16 J B 1.7 ND<9.2 NA

TPG-4 2008 2-2.5 0.089 J B 16 32 J NA5-5.5 0.054 J B 5.3 20 J NA

10-10.5 0.10 J B 1.1 ND<9.2 NA15-15.5 0.45 B 7.5 ND<9.2 NA20-20.5 4.5 47 45 J NA24.5-25 0.079 J B ND<0.37 ND<9.1 NA

TPG-5 2008 2-2.5 0.047 J B 22 110 NA5-5.5 0.070 J B 0.79 J ND<9.1 NA

10-10.5 0.082 J B 6.3 32 J NA15-15.5 0.083 J B 11 53 NA20-20.5 0.061 J B 0.47 J ND<9.2 NA24.5-25 0.060 J B ND<0.38 ND<9.2 NA

Notes:Results are presented in milligrams per kilogram (mg/kg)."ND<" indicates the constituent was not detected at or above the laboratory reporting limit or method detection limit.bgs = below ground surfaceDUP = duplicateNA = not analyzedTPHg = total petroleum hydrocarbons quantified as gasoline. Samples were analyzed using United States Environmental Protection Agency (USEPA) Method 8015M, except for samples collected in 2008, which were analyzed by USEPA Method 8260B/5035.TPHd = total petroleum hydrocarbons quantified as diesel. Samples were analyzed using USEPA Method 8015M.TPHmo = total petroleum hydrocarbons quantified as motor oil. Samples were analyzed using USEPA Method 8015M.TRPH - total recoverable petroleum hydrocarbons. Samples were analyzed using USEPA Method 418.1.B = estimated value; analyte detected in the sample and the assocaited method blank. Analyte was detected at a concentrationless than 10 times the concentration detected in method blank.J = estimated value; analyte detected at a concentration less than the reporting limit and greater than or equal to the method detection limit

Table 2-1DSummary of BTEX and MTBE Concentrations in Soil Samples


Page 1 of 2

Location IDYear

SampledSample Depth

(feet bgs) Benzene Toluene EthylbenzeneTotal

Xylenes MTBEB-WAT1-1 1991 10 NA NA NA 0.0012 NA

15 NA NA NA ND<0.001 NAMW-WAT1-1 1991 8 NA NA NA ND<0.001 NA

12 NA NA NA ND<0.001 NA18 NA NA NA ND<0.001 NA20 NA NA NA ND<0.001 NA

MW-WAT1-2 1991 4 NA 0.0013 ND<0.001 0.0021 NA5 NA ND<0.001 ND<0.001 ND<0.001 NA10 NA ND<0.001 ND<0.001 ND<0.001 NA

11.5 NA ND<0.001 ND<0.001 ND<0.001 NA13 NA 0.022 0.028 0.011 NA

MW-WAT1-3 1991 10 NA ND<0.001 ND<0.001 ND<0.001 NA13 NA 2.8 4.8 65 NA15 NA 12 11 110 NA18 NA ND<0.28 ND<0.28 1.6 NA20 NA 0.072 0.06 0.48 NA23 NA 0.0011 ND<0.001 0.0024 NA25 NA ND<0.001 ND<0.001 ND<0.001 NA

SS-WAT1-1 2001 1 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.0052.5 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005



SS-WAT1-4 2001 1 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.0052.5 ND<0.005 ND<0.005 ND<0.005 0.0064 ND<0.005






B-WAT1-2 2001 6.5 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.00510 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.00515 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005

B-WAT1-3 2001 6.5 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.00510 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.00515 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005

MW-WAT1-4 2001 6.5 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.00510 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.00515 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.00520 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005

MW-WAT1-5 2001 6.5 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.00510 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.00515 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.00520 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005

GP1 2004 2.5-3 ND<0.0017 ND<0.0017 ND<0.0017 ND<0.0017 NA5-5.5 ND<0.0016 ND<0.0016 ND<0.0016 ND<0.0016 NA

10-10.5 ND<0.20 ND<0.20 ND<0.20 0.52 NA15-15.5 ND<15 19 28 400 NA20-20.5 ND<0.0017 0.011 0.01 0.1 NA20-20.5 ND<0.0036 0.0047 0.0039 0.038 NA24-24.5 ND<0.0055 ND<0.0055 ND<0.0055 0.012 NA

Table 2-1DSummary of BTEX and MTBE Concentrations in Soil Samples


Page 2 of 2

Location IDYear

SampledSample Depth

(feet bgs) Benzene Toluene EthylbenzeneTotal

Xylenes MTBEGP2 2004 2.5-3 ND<0.0050 ND<0.0050 ND<0.0050 ND<0.0050 NA

5-5.5 ND<0.0050 ND<0.0050 ND<0.0050 ND<0.0050 NA5-5.5 ND<0.0050 ND<0.0050 ND<0.0050 ND<0.0050 NA



10-10.5 ND<0.0019 ND<0.0019 ND<0.0019 ND<0.0019 NA15-15.5 ND<0.0026 ND<0.0026 ND<0.0026 ND<0.0026 NA20-20.5 ND<0.0016 ND<0.0016 ND<0.0016 ND<0.0016 NA23.5-24 ND<0.0033 ND<0.0033 ND<0.0033 ND<0.0033 NA


10-10.5 ND<0.0017 ND<0.0017 ND<0.0017 ND<0.0017 NA15-15.5 ND<8.7 ND<8.7 ND<8.7 80 NA20-20.5 ND<0.0022 0.0027 ND<0.0022 0.012 NA23.5-24 ND<0.0022 ND<0.0022 0.012 0.038 NA

TPG-1 2008 2-2.5 0.00029 J ND<0.00017 ND<0.00025 ND<0.00050 NA5-5.5 0.00075 J 0.00026 J B ND0.00027 ND<0.00054 NA

10-10.5 ND<0.00025 0.00023 J B ND<0.00025 ND<0.00050 NA16-16.5 ND<0.00022 0.00028 J B ND<0.00022 ND<0.00044 NA19.5-20 ND<0.00020 0.00021 J B ND<0.00020 ND<0.00041 NA23.5-24 0.0013 J 0.00061 J B 0.00035 J 0.00097 J B NA

TPG-2 2008 2-2.5 0.0017 J 0.0014 J B ND<0.00025 0.0011 J B NA5-5.5 0.028 0.034 B 0.0036 J 0.034 B NA

10-10.5 ND<0.00025 0.00041 J B ND<0.00025 ND<0.00050 NA15-15.5 0.00050 J 0.00039 J B 0.00021 J 0.00084 J B NA20-20.5 0.00020 J 0.00026 J B ND<0.00020 ND<0.00040 NA24.5-25 0.00035 J 0.00026 J B ND<0.00025 ND<0.00050 NA

TPG-3 2008 2-2.5 ND<0.00025 ND<0.00017 ND<0.00025 ND<0.00050 NA5-5.5 ND<0.00025 0.00028 J B ND<0.00025 ND<0.00051 NA

12-12.5 ND<0.31 0.74 J B ND <0.25 0.60 J NA15-15.5 0.00027 J 0.00034 J B ND<0.00025 ND<0.00049 NA20-20.5 0.00061 J 0.00033 J B ND<0.00023 ND<0.00047 NA24.5-25 ND<0.00029 0.00041 J B 0.00044 J ND<0.00057 NA

TPG-4 2008 2-2.5 0.00021 J 0.00032 J B ND<0.00020 ND<0.00040 NA5-5.5 ND<0.00025 0.00019 J B ND<0.00025 ND<0.00051 NA

10-10.5 ND<0.00026 0.00029 J B ND<0.00026 ND<0.00051 NA15-15.5 0.00083 J 0.0026 J B 0.0037 J 0.021 NA20-20.5 0.0017 J 0.017 0.031 0.23 NA24.5-25 0.00036 J 0.00035 J B ND<0.00021 ND<0.00042 NA

TPG-5 2008 2-2.5 0.00044 J 0.00042 J B ND<0.00023 ND<0.00045 NA5-5.5 ND<0.00023 0.00022 J B ND<0.00023 ND<0.00046 NA

10-10.5 ND<0.00029 0.00033 J B ND<0.00029 ND<0.0005 NA15-15.5 0.00047 J 0.00056 J B ND<0.00030 ND<0.00061 NA20-20.5 0.00033 J 0.00023 J B ND<0.00024 ND<0.00047 NA24.5-25 0.00032 J 0.00033 J B ND<0.00031 ND<0.00061 NA

Notes:All results are presented in milligrams per kilogram (mg/kg).ND< indicates the constituent was not detected at or above the laboratory reporting limit or method detection limit.BTEX = benzene, toluene, ethylbenzene, and total xylenesMTBE = methyl tertiary-butyl etherNA = not analyzedJ = estimated value; analyte detected at a concentration less than the reporting limit and greater than or equal to the method detection limit.B = estimated value; analyte detected in the sample and the assocaited method blank. Analyte was detected at a concentrationless than 10 times the concentration detected in method blank.1991 samples analyzed by United States Environmental Protection Agency (USEPA) Method 80202001 and 2004 samples analyzed by USEPA Method 8021B/50352008 samples analyzed by USEPA Method 8260B/5035

Table 2-1ESummary of Ammonia, Cyanide, Sulfide, and Total Phenols Concentrations in Soil Samples


Page 1 of 2

Ammonia CyanideSulfide

(Extractable)Total

Phenols350.2 or 350.3(1) 335.2 or 9010B(2) 376.1 420.1

Location IDYear

SampledSample Depth

(feet bgs)MT-408-8-1 1986 0 NA ND<1.0 NA NA

DSS-WAT1-1 1991 0 16.7 ND<0.57 ND<2.28 NADSS-WAT1-2 1991 0 13.5 0.81 ND<2.22 NADSS-WAT1-3 1991 0 10.3 ND<0.56 ND<2.26 NADSS-WAT1-4 1991 0 19.7 ND<0.6 ND<2.42 NADSS-WAT1-5 1991 0 20.4 2.95 ND<2.14 NA

0 DUP 11.9 1.06 ND<2.16 NAB-WAT1-1 1991 3.5 4.34 ND<0.58 ND<2.23 ND<2.9

10 ND<1.76 ND<0.59 ND<2.34 ND<2.9215 ND<1.7 ND<0.57 ND<2.27 ND<2.85

MW-WAT1-1 1991 3 6.35 ND<0.58 ND<2.33 5.18 ND<1.75 ND<0.58 3.05 ND<2.9212 ND<1.73 ND<0.58 ND<2.3 ND<2.8818 ND<1.69 ND<0.56 ND<2.25 ND<2.8220 ND<1.67 ND<0.56 ND<2.22 ND<2.77

MW-WAT1-2 1991 4 6.64 5.26 ND<2.32 ND<2.95 5.23 14.3 ND<2.28 ND<2.8510 ND<1.7 0.57 ND<2.27 ND<2.85

11.5 4.11 0.66 ND<2.28 ND<2.8513 117 13.1 ND<2.34 ND<2.92

13 DUP 122 1.67 ND<2.29 5.0415 278 ND<0.58 ND<2.31 ND<2.88

MW-WAT1-3 1991 3.5 ND<3.47 ND<0.58 ND<2.31 ND<2.910 25.5 ND<0.59 ND<2.36 ND<2.9513 167 ND<0.56 ND<2.24 10.9

13 DUP 116 ND<0.57 ND<2.28 ND<2.8515 232 ND<0.56 ND<2.26 8.7918 375 ND<0.56 ND<2.25 ND<2.8220 151 ND<0.58 ND<2.32 ND<2.923 3.37 ND<0.56 ND<2.25 ND<2.8225 48.4 ND<0.57 ND<2.27 ND<2.85

SS-WAT1-1 2001 1 ND<5 ND<0.5 NA NA2.5 ND<5 ND<0.5 NA NA

SS-WAT1-2 2001 1 ND<5 ND<0.5 NA NA1 DUP ND<5 ND<0.5 NA NA

2.5 ND<5 ND<0.5 NA NASS-WAT1-3 2001 1 ND<5 ND<0.5 NA NA


2.5 ND<5 0.62 NA NASS-WAT1-5 2001 1 ND<5 ND<0.5 NA NA

2.5 5.6 0.78 NA NASS-WAT1-6 2001 1 ND<5 ND<0.5 NA NA




2.5 ND<5 ND<0.5 NA NAB-WAT1-2 2001 6.5 ND<0.5 ND<0.01 NA NA

10 ND<0.5 ND<0.01 NA NA15 ND<0.5 ND<0.01 NA NA

B-WAT1-3 2001 6.5 ND<0.5 ND<0.01 NA NA10 ND<0.5 ND<0.01 NA NA

10 DUP ND<0.5 ND<0.01 NA NA15 ND<0.5 ND<0.01 NA NA

USEPA MethodAnalyte

Table 2-1ESummary of Ammonia, Cyanide, Sulfide, and Total Phenols Concentrations in Soil Samples


Page 2 of 2


(Extractable)Total

Phenols350.2 or 350.3(1) 335.2 or 9010B(2) 376.1 420.1

Location IDYear

SampledSample Depth

(feet bgs)

USEPA MethodAnalyte

MW-WAT1-4 2001 6.5 ND<5 ND<0.5 NA NA10 ND<5 ND<0.5 NA NA15 ND<5 ND<0.5 NA NA20 ND<5 ND<0.5 NA NA

MW-WAT1-5 2001 6.5 ND<5 ND<0.5 NA NA10 ND<5 ND<0.5 NA NA15 ND<5 ND<0.5 NA NA20 ND<5 ND<0.5 NA NA

20 DUP ND<5 ND<0.5 NA NA

Notes:All results are presented in milligrams per kilogram (mg/kg)."ND<" indicates the constituent was not detected at or above the laboratory reporting limit.bgs = below ground surfaceNA = not analyzedUSEPA = United States Environmental Protection Agency(1) 1991 samples analyzed for ammonia by USEPA Method 350.2; 2001 samples analyzed for ammonia by USEPA Method 350.3.(2) 1991 samples analyzed for cyanide by USEPA Method 335.2; 2001 samples analyzed for cyanide by USEPA Method 9010B.* analytical method not known

Table 2-1FSummary of Physical Testing Results for Soil Samples


Page 1 of 1

Porosity (API

RP40)

Porosity (%)

Specific Gravity

(unitless)

Wet Density

(pcf)

Dry Density

(pcf)

Moisture Content

(%)

Passing No. 200 Sieve

(%)

Laboratory USCS

Classification

10/5/2009 MW-WAT1-6-5' 5 - 5.5 29.3 2.688 137 119 15.7 43.2 SC10/5/2009 MW-WAT1-6-10' 10 - 10.5 42.3 2.671 113 96 17.2 17.6 SC10/5/2009 MW-WAT1-6-15' 15 - 15.5 38.8 2.731 119 105 13.8 11.7 SP-SC10/6/2009 MW-WAT1-7-4.5' 4.5 - 5 33.3 2.698 131 112 16.4 48.0 SC10/6/2009 MW-WAT1-7-10.5' 10.5 - 11 34.9 2.670 123 109 13.1 11.9 SP-SC10/7/2009 MW-WAT1-7-16' 16 - 16.5 31.0 2.682 126 115 9.5 8.7 SP-SC

Notes:API = America Petroleum InstituteASTM = American Society for Testing and Materialsbgs = below ground surfaceUSCS = Unified Soil Classification System % = percentbgs = below ground surfacepcf = pounds per cubic footSC = clayey sandSP-SC = sand with clay and gravel

MW-WAT1-7

MW-WAT1-6 35.5

36

Sample Interval (feet bgs)

Moiture Content and Unit Weight (ASTM D-854, D-2216 & D-2937)

Sample ID

Sieve Anlaysis (ASTM D-422) or Percent Passing 200 Sieve

(ASTM D-1140)

Analyses (Method Number)

Sample DateBoring IDTotal Depth of Boring(feet bgs)

Table 2-2ASummary of PAH Concentrations in Background Soil Samples


Page 1 of 1

Location ID DSS-WAT1-6 DSS-WAT1-7 DSS-WAT1-8 DSS-WAT1-9 DSS-WAT1-10Sample Depth (feet bgs) 0 0 0 0 0

Sample Date 6/24/1991 6/24/1991 6/24/1991 6/24/1991 6/24/1991Laboratory CH2M Hill CH2M Hill CH2M Hill CH2M Hill CH2M Hill

Non-CarcinogenicAcenaphthylene ND<0.079 ND<0.076 ND<0.078 ND<0.069 ND<0.076Acenaphthene ND<0.079 ND<0.076 ND<0.078 ND<0.069 ND<0.076

Anthracene ND<0.079 ND<0.076 ND<0.078 ND<0.069 ND<0.076Benzo(g,h,i)perylene 0.18 ND<0.076 ND<0.078 ND<0.069 ND<0.076

Fluoranthene 0.58 0.14 0.13 0.18 ND<0.076Fluorene ND<0.079 ND<0.076 ND<0.078 ND<0.069 ND<0.076

Phenanthrene 0.35 ND<0.076 ND<0.078 0.11 ND<0.076Pyrene ND<0.079 ND<0.076 ND<0.078 ND<0.069 ND<0.076

CarcinogenicBenzo(a)anthracene 0.16 ND<0.076 ND<0.078 ND<0.069 ND<0.076

Benzo(a)pyrene 0.23 ND<0.076 ND<0.078 ND<0.069 ND<0.076Benzo(b)fluoranthene 0.41 0.12 0.089 0.11 ND<0.076Benzo(k)fluoranthene 0.12 ND<0.076 ND<0.078 ND<0.069 ND<0.076

Chrysene ND<0.079 ND<0.076 ND<0.078 ND<0.069 ND<0.076Dibenzo(a,h)anthracene 0.23 0.084 ND<0.078 ND<0.069 ND<0.076Indeno(1,2,3-cd)pyrene 0.26 ND<0.076 ND<0.078 ND<0.069 ND<0.076

Naphthalene ND<0.079 ND<0.076 ND<0.078 ND<0.069 ND<0.076B(a)P Equivalent 0.404 0.090 0.073 0.068 0.067

Notes:All results are presented in milligrams per kilogram (mg/kg).Samples were analyzed by USEPA Method 8310, except for samples collected in 2008 which were analyzed using USEPA Method 8270SIM."ND<" indicates the constituent was not detected at or above the laboratory reporting limit.BaP = benzo(a)pyrenebgs = below ground surfacePAH = polycyclic aromatic hydrocarbonUSEPA = United States Environmental Protection AgencyBenzo(a)pyrene equivalents represent the sum of the concentration of each carcinogenic PAH multiplied by its toxicity equivalence factor (except for naphthalene).D = sample diluted to bring the analyte concentration within calibration rangeJ = estimated value; analyte detected at a concentration less than the reporting limit and greater than or equal to the method detection limit

Table 2-2BSummary of TPH and TRPH Concentrations in Background Soil Samples


Page 1 of 1

TPHg TPHd TPHmoDSS-1-WAT1-6 0 (surface soil) 6/24/1991 ND<1.2 ND<23 NA 27.1DSS-1-WAT1-7 0 (surface soil) 6/24/1991 1.3 ND<110 NA 364DSS-1-WAT1-8 0 (surface soil) 6/24/1991 ND<1.2 ND<23 NA 55.4DSS-1-WAT1-9 0 (surface soil) 6/24/1991 ND<1 ND<20 NA 86.1DSS-1-WAT1-10 0 (surface soil) 6/24/1991 ND<1.1 ND<110 NA 158

Notes:Results are presented in milligrams per kilogram (mg/kg)."ND<" indicates the consitituent was not detected at or above the laboratory reporting limit.bgs = below ground surfaceUSEPA = United States Environmental Protection AgencyNA = not analyzedTPHg = total petroleum hydrocarbons quantified as gasoline. Samples were analyzed using USEPA Method 8015M. TPHd = total petroleum hydrocarbons quantified as diesel. Samples were analyzed using USEPA Method 8015M.TPHmo = total petroleum hydrocarbons quantified as motor oil. TRPH = total recoverable petroleum hydrocarbons. Samples were analyzed using USEPA Method 418.1.

TRPHLocation ID Total Petroleum HydrocarbonsDate SampledSample Depth(feet bgs)

Table 2-2CSummary of Metals Concentrations in Background Soil Samples


Page 1 of 1

DSS-WAT1-6 DSS-WAT1-7 DSS-WAT1-8 DSS-WAT1-9 DSS-WAT1-100 0 0 0 0

6/24/1991 6/24/1991 6/24/1991 6/24/1991 6/24/1991Analyte USEPA MethodAntimony 6010 4.6 5.5 2 6.5 ND<1.8Arsenic 7060 2.04 1.45 27 1.47 1.25Barium 6010 98 89.5 98.3 58.5 68.7Beryllium 6010 ND<0.2 0.3 ND<0.2 ND<0.2 ND<0.2Cadmium 6010 0.6 0.7 0.7 0.8 0.3Chromium (Hexavalent) 7196 ND<11.7 ND<11.3 ND<11.7 12 ND<11.4Chromium (total) 6010 41.9 34.2 27.8 42.9 12Cobalt 6010 10.9 8 8.1 11.7 7.1Copper 6010 62.4 28.7 31.8 59 37.7Lead 6010 75.2 73.7 192 142 32.4Mercury 7571 0.16 0.51 ND<0.07 0.22 ND<0.07Molybdenum 6010 ND<0.5 ND<0.5 0.8 ND<0.4 ND<0.5Nickel 6010 43.1 30.1 25.2 32 10.9Selenium 7740 ND<0.19 ND<0.18 ND<0.19 ND<0.16 ND<0.18Silver 6010 ND<0.2 ND<0.2 ND<0.2 ND<0.2 ND<0.2Thallium 7841 ND<0.21 ND<0.2 ND<0.21 ND<0.18 ND<0.2Vanadium 6010 37.2 39.7 36 55.2 31.8Zinc 6010 99 77.5 105 103 99

Notes:All results are presented in milligrams per kilogram (mg/kg)."ND<" indicates the consitituent was not detected at or above the laboratory reporting limit.bgs = below ground surfaceUSEPA = United States Environmental Protection Agency

Location IDSample Depth (feet bgs)

Sample Date

Table 2-2DSummary of Ammonia, Cyanide, and Sulfide Concentrations in Background Soil Samples


Page 1 of 1


(Extractable)350.2 335.2 376.1

Boring/Sample IDSample Depth

(feet bgs)Sample

DateDSS-WAT1-6 0 6/24/1991 18 ND<0.59 ND<2.35DSS-WAT1-7 0 6/24/1991 15.4 ND<0.56 ND<2.26DSS-WAT1-8 0 6/24/1991 17.6 ND<0.58 ND<2.33DSS-WAT1-9 0 6/24/1991 18.1 ND<0.51 ND<2.04DSS-WAT1-10 0 6/24/1991 15.3 ND<0.57 ND<2.27

Notes:All results are presented in milligrams per kilogram (mg/kg)."ND<" indicates the consitituent was not detected at or above the laboratory reporting limit.bgs = below ground surfaceUSEPA = United States Environmental Protection Agency

AnalyteUSEPA Method

Table 2-3ASummary of PAH Concentrations in Groundwater Samples


Page 1 of 5

Well ID

Date Sampled

Acenaph-thene

Acenaph-thylene

Anthra-cene

Benzo(a)Anthra-

cene

Benzo(b)Fluoran-

thene

Benzo(k)Fluoran-

thene

Benzo(g,h,i)

peryleneBenzo(a)pyrene Chrysene

Dibenz(a,h)

Anthra-cene

Fluoran-thene Fluorene

Indeno-(1,2,3-cd)-

pyreneNaph-

thalenePhenan-threne Pyrene

µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/LMW-WAT1-1 6/24/1991 Unfiltered <5 <5 <5 <5 <5 <5 <5 <5 <5 <5 <5 <5 <5 <5 <5 <5

10/17/1997 Filtered <0.1 <0.1 <0.051 <0.15 <0.1 <0.051 <0.1 <0.1 <0.1 <0.1 <0.2 <0.1 <0.1 <0.1 <0.1 <0.15 10/17/1997 Unfiltered <0.1 <0.1 <0.051 <0.15 <0.1 <0.051 <0.1 <0.1 <0.1 <0.1 <0.2 <0.1 <0.1 <0.1 <0.1 <0.15 4/16/1998 Filtered NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC4/16/1998 Unfiltered <0.1 <0.1 <0.05 <0.15 <0.1 <0.05 <0.1 <0.1 <0.1 <0.1 <0.2 <0.1 <0.1 <0.1 <0.1 <0.15 6/19/1998 Unfiltered <10 <10 <0.5 <0.5 <1 <0.5 <2 <0.5 <0.5 <2 <1 <1 <0.5 <5 <0.5 <1 10/16/1998 Filtered NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC10/16/1998 Unfiltered <0.1 <0.1 <0.05 <0.15 <0.1 <0.05 <0.1 <0.1 <0.1 <0.1 <0.2 <0.1 <0.1 <0.1 <0.1 <0.15 4/15/1999 Filtered <0.1 <0.1 <0.052 <0.15 <0.1 <0.052 <0.1 <0.1 <0.1 <0.1 <0.21 <0.1 <0.1 0.67 <0.1 <0.15 4/15/1999 Unfiltered <0.1 <0.1 <0.05 <0.15 <0.1 <0.05 <0.1 <0.1 <0.1 <0.1 <0.2 <0.1 <0.1 0.14 <0.1 <0.15 10/26/1999 Filtered NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC10/26/1999 Unfiltered <1 <10 <0.5 <0.1 <0.2 <0.1 <0.2 <0.1 <0.1 <0.2 <0.4 <1 <0.14 <5 <0.5 <0.2 4/13/2000 Filtered <0.1 <0.1 <0.05 <0.1 <0.1 <0.05 <0.1 <0.1 <0.1 <0.1 <0.15 <0.1 <0.1 <0.15 <0.1 <0.15 10/5/2000 Filtered <0.1 <0.1 <0.05 <0.1 <0.1 <0.05 <0.1 <0.1 <0.1 <0.1 <0.15 <0.1 <0.1 <0.15 <0.1 <0.15 3/27/2001 Filtered <0.1 <0.1 <0.05 <0.1 <0.1 <0.05 <0.1 <0.1 <0.1 <0.1 <0.15 <0.1 <0.1 <0.15 <0.1 <0.15

10/26/2001 Filtered <0.1 <0.1 <0.05 <0.1 <0.1 <0.05 <0.1 <0.1 <0.1 <0.1 <0.15 <0.1 <0.1 <0.15 <0.1 <0.15 4/23/2002 Filtered <0.1 <0.1 <0.05 <0.1 <0.1 <0.05 <0.1 <0.1 <0.1 <0.1 <0.15 <0.1 <0.1 <0.15 <0.1 <0.15 10/29/2002 Filtered <5 <2 <0.05 <0.1 <0.1 <0.05 <0.1 <0.1 <0.1 <0.18 <0.15 <0.1 <0.1 <5 <0.1 <0.15 4/28/2003 Filtered <5 <2 <0.05 <0.1 <0.1 <0.05 <0.1 <0.1 <0.1 <0.18 <0.15 <0.1 <0.1 <5 <0.1 <0.15 11/20/2003 Filtered <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <0.20 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 0.062 J 0.64 J5/12/2004 Filtered <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <0.20 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.011/9/2004 Filtered <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <0.20 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.05/12/2005 Filtered <0.94 <0.94 <0.94 <0.94 <0.94 <0.94 <0.94 <0.19 <0.94 <0.94 <0.94 <0.94 <0.94 <0.94 <0.94 <0.948/2/2006 Filtered <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <0.20 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0

12/19/2006 Filtered <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <0.20 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.06/26/2007 Filtered <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.1111/15/2007 Filtered <0.12 <0.12 <0.12 <0.12 <0.12 <0.12 <0.12 <0.12 <0.12 <0.12 <0.12 <0.12 <0.12 <0.12 <0.12 <0.124/22/2008 Filtered <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.1111/6/2008 Filtered <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.114/8/2009 Filtered <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10

10/12/2009 Filtered <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10MW-WAT1-2 6/24/1991 Unfiltered 8.6 8.6 <5 <5 <5 <5 <5 <5 <5 <5 <5 5.5 <5 5.2 <5 <5

10/17/1997 Filtered <0.12 <0.12 <0.059 <0.12 <0.12 <0.059 <0.12 <0.12 <0.12 <0.12 <0.24 <0.12 <0.11 <0.12 <0.12 <0.18 10/17/1997 Unfiltered <0.11 <0.11 <0.056 <0.11 <0.11 <0.056 <0.11 <0.11 <0.11 <0.11 <0.22 <0.11 <0.11 <0.11 <0.11 <0.17

Units



Page 2 of 5

Well ID

Date Sampled

Acenaph-thene

Acenaph-thylene

Anthra-cene

Benzo(a)Anthra-

cene

Benzo(b)Fluoran-

thene

Benzo(k)Fluoran-

thene

Benzo(g,h,i)


Dibenz(a,h)

Anthra-cene


Indeno-(1,2,3-cd)-

pyreneNaph-


µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/LUnitsMW-WAT1-2 4/16/1998 Filtered <0.1 3.8 0.17 <0.15 <0.1 <0.05 <0.1 <0.1 <0.1 <0.1 <0.2 <0.1 <0.1 <0.1 <0.1 0.36(continued) 4/16/1998 Unfiltered <0.1 2.6 0.75 0.4 <0.1 <0.05 0.74 <0.1 0.39 <0.1 1.4 <0.1 0.32 <0.1 <0.1 1.2

6/19/1998 Unfiltered <10 <10 <0.5 <0.5 <1 <0.5 <2 <0.5 <0.5 <2 <1 <1 <0.5 <5 <0.5 <1 10/16/1998 Filtered NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC10/16/1998 Unfiltered NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC4/15/1999 Filtered <0.1 <0.1 <0.05 <0.15 <0.1 <0.05 <0.1 <0.1 <0.1 <0.1 <0.2 <0.1 <0.1 <0.1 <0.1 <0.15 4/15/1999 Unfiltered 11 <2 <1 <3.1 <2 <1 <2 <2 <2 <2 <4.1 21 <2 410 8.7 <3.1 10/26/1999 Filtered NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC10/26/1999 Unfiltered NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC4/13/2000 Filtered <0.1 <0.1 <0.05 <0.1 <0.1 <0.05 <0.1 <0.1 <0.1 <0.1 <0.15 <0.1 <0.1 <0.15 <0.1 <0.15 10/5/2000 Filtered NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC3/27/2001 Filtered <0.1 <0.1 <0.05 <0.1 <0.1 <0.05 <0.1 <0.1 <0.1 <0.1 <0.15 <0.1 <0.1 <0.15 <0.1 <0.15 10/26/2001 Filtered NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC4/23/2002 Filtered NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC10/29/2002 Filtered NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC4/28/2003 Filtered NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC

11/20/2003 Filtered NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC5/12/2004 Filtered <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <0.20 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.011/9/2004 Filtered NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC5/12/2005 Filtered <0.94 <0.94 <0.94 <0.94 <0.94 <0.94 <0.94 <0.19 <0.94 <0.94 <0.94 <0.94 <0.94 <0.94 <0.94 <0.948/2/2006 Filtered <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <0.20 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0

12/19/2006 Filtered NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC6/26/2007 Filtered <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.1011/15/2007 Filtered <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.114/22/2008 Filtered <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.1011/6/2008 Filtered <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.104/8/2009 Filtered <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10

10/13/2009 Filtered NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NCMW-WAT1-3 6/24/1991 Unfiltered 40 74 20 <5 <5 <5 <5 <5 <5 <5 <5 42 <5 <5 33 16

10/17/1997 Filtered <0.1 <0.1 <0.051 <0.15 <0.1 <0.051 <0.1 <0.1 <0.1 <0.1 <0.2 <0.1 <0.1 11 <0.1 <0.15 10/17/1997 Unfiltered 4.6 0.72 11 <0.11 <0.11 <0.054 <0.11 <0.11 0.24 <0.11 1.4 7.9 <0.11 18 <0.11 <0.16 4/16/1998 Filtered 11 230 1.8 <3 <2 <1 <2 <2 <2 <2 8 12 <2 260 2.5 <3 4/16/1998 Unfiltered 12 230 3.1 <3 <2 <1 <2 <2 <2 <2 <4 19 <2 290 4.4 <3 6/19/1998 Unfiltered <10 120 1.9 <0.5 <1 <0.5 <2 <0.5 <0.5 <2 <1 11 <0.5 <5 2.6 <1



Page 3 of 5

Well ID

Date Sampled

Acenaph-thene

Acenaph-thylene

Anthra-cene

Benzo(a)Anthra-

cene

Benzo(b)Fluoran-

thene

Benzo(k)Fluoran-

thene

Benzo(g,h,i)


Dibenz(a,h)

Anthra-cene


Indeno-(1,2,3-cd)-

pyreneNaph-


µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/LUnitsMW-WAT1-3 10/16/1998 Filtered <0.1 <0.1 <0.05 <0.15 <0.1 <0.05 <0.1 <0.1 <0.1 <0.1 <0.2 <0.1 <0.1 0.4 <0.1 <0.15 (continued) 10/16/1998 Unfiltered <0.1 <0.1 2.4 <0.15 <0.1 <0.05 <0.1 0.51 <0.1 <0.1 1.3 <0.1 <0.1 1.7 <0.1 0.7

4/15/1999 Filtered NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC4/15/1999 Unfiltered <2.2 <2.2 1.9 <3.3 <2.2 <1.1 <2.2 <2.2 <2.2 <2.2 <4.3 23 <2.2 440 6.5 <3.3 10/26/1999 Filtered <1 <10 4.6 <0.1 <0.2 <0.1 <0.2 <0.1 <0.1 <0.2 <0.4 5 <0.14 34 <0.5 <0.2 10/26/1999 Unfiltered <1 <10 6.4 0.2 <0.2 <0.1 <0.2 0.2 0.4 <0.2 1.2 5.4 <0.14 38 <0.5 1.14/13/2000 Filtered <2 <2 <1 <2 <2 <1 <2 <2 <2 <2 <3 19 <2 510 5.8 <3 10/5/2000 Filtered <0.1 <0.1 0.73 <0.1 <0.1 <0.05 <0.1 <0.1 <0.1 <0.1 <0.15 <0.1 <0.1 <0.15 <0.1 <0.15 3/27/2001 Filtered <5 <5 <2.5 <5 <5 <2.5 <5 <5 <5 <5 <7.5 <5 <5 97 <5 <7.5

10/26/2001 Filtered 0.33 0.95 0.6 <0.1 <0.1 <0.05 <0.1 <0.1 <0.1 <0.1 0.28 0.67 <0.1 <0.15 <0.1 <0.15 4/23/2002 Filtered 18 19 1.5 <0.1 <0.1 <0.05 <0.1 <0.1 <0.1 <0.1 0.98 1.6 <0.1 13 0.46 0.9710/29/2002 Filtered <5 <2 <0.05 <0.1 <0.1 <0.05 <0.1 <0.1 <0.1 <0.18 <0.15 <0.1 <0.1 <5 <0.1 <0.15 4/28/2003 Filtered <5 26 J 0.93 J <0.1 <0.1 <0.05 <0.1 <0.1 <0.1 <0.18 0.37 1.4 J <0.1 14 J 0.07 J 0.2511/20/2003 Filtered <1.0 <1.0 0.16 J 0.15 J <1.0 <1.0 <1.0 <0.20 <1.0 <1.0 0.41 J <1.0 <1.0 <1.0 0.18 J <1.05/12/2004 Filtered <1.0 <1.0 1.7 <1.0 <1.0 <1.0 <1.0 <0.20 <1.0 <1.0 0.60J 2.2 <1.0 42 0.14J 0.27J11/9/2004 Filtered <1.0 <1.0 2.1 <1.0 <1.0 <1.0 <1.0 <0.20 <1.0 <1.0 0.66 J <1.0 <1.0 <1.0 0.068 J 0.70 J5/12/2005 Filtered <0.94 <0.94 0.53 J <0.94 <0.94 <0.94 <0.94 <0.19 <0.94 <0.94 <0.94 7.4 <0.94 NA 0.73 J <0.948/2/2006 Filtered 2.7 19 <1.0 <1.0 <1.0 <1.0 <1.0 <0.20 <1.0 <1.0 <1.0 7.5 <1.0 23 <1.0 <1.0

12/19/2006 Filtered <1.0 3.1 <1.0 <1.0 <1.0 <1.0 <1.0 <0.20 <1.0 <1.0 <1.0 <1.0 <1.0 2.1 <1.0 <1.06/26/2007 Filtered 1.7 1.8 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 0.48 <0.10 3.3 <0.10 <0.1011/15/2007 Filtered 0.15 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 0.12 <0.11 <0.114/22/2008 Filtered 3.4 3.3 0.82 <0.51 <0.51 <0.51 <0.51 <0.51 <0.51 <0.51 <0.51 2.3 <0.51 29 <0.51 <0.5111/6/2008 Filtered 3.9 8.8 <2.0 <2.0 <2.0 <2.0 <2.0 <2.0 <2.0 <2.0 <2.0 2.3 <2.0 99 <2.0 <2.04/8/2009 Filtered 13 16 <5.2 <5.2 <5.2 <5.2 <5.2 <5.2 <5.2 <5.2 <5.2 12 <5.2 450 <5.2 <5.2

10/13/2009 Filtered 1.3 1.1 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 0.30 <0.10 3.0 <0.10 <0.10MW-WAT1-3 4/16/1998 Filtered 9.7 210 1.2 <1.5 <1 <0.5 <1 <1 <1 <1 <2 10 <1 250 1.8 <1.5

duplicate 4/16/1998 Unfiltered 18 360 4 <3 <2 <1 <2 <2 <2 <2 <4 22 <2 360 5.4 <3 6/19/1998 Unfiltered <10 160 2.1 <0.5 <1 <0.5 <2 <0.5 <0.5 <2 <1 13 <0.5 77 2.6 <1 10/16/1998 Filtered <0.1 <0.1 <0.05 <0.15 <0.1 <0.05 <0.1 <0.1 <0.1 <0.1 <0.2 <0.1 <0.1 <0.1 <0.1 <0.15 10/16/1998 Unfiltered <0.1 <0.1 2.6 0.2 <0.1 <0.05 <0.1 0.36 <0.1 <0.1 1.3 <0.1 <0.1 1.6 <0.1 0.494/15/1999 Unfiltered <2 <2 <1 <3 <2 <1 <2 <2 <2 <2 <4 27 <2 440 8.8 <3

10/26/1999 Filtered <1 <10 4 <0.1 <0.2 <0.1 <0.2 <0.1 <0.1 <0.2 <0.4 4.2 <0.14 32 <0.5 <0.2 10/26/1999 Unfiltered <1 <10 6.6 0.2 <0.2 <0.1 <0.2 0.1 0.3 <0.2 1.1 6 <0.14 39 <0.5 14/13/2000 Filtered <2 <2 <1 <2 <2 <1 <2 <2 <2 <2 <3 19 <2 580 5.4 <3



Page 4 of 5

Well ID

Date Sampled

Acenaph-thene

Acenaph-thylene

Anthra-cene

Benzo(a)Anthra-

cene

Benzo(b)Fluoran-

thene

Benzo(k)Fluoran-

thene

Benzo(g,h,i)


Dibenz(a,h)

Anthra-cene


Indeno-(1,2,3-cd)-

pyreneNaph-


µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/LUnitsMW-WAT1-3 10/5/2000 Filtered 1.2 <0.1 1.4 <0.1 <0.1 <0.05 <0.1 <0.1 <0.1 <0.1 <0.15 1.8 <0.1 4.5 <0.1 <0.15

duplicate 3/27/2001 Filtered <0.96 <0.96 4.1 <0.96 <0.96 <0.48 <0.96 <0.96 <0.96 <0.96 <1.4 7.6 <0.96 120 3.6 <1.4 (continued) 10/29/2002 Filtered <5 <2 <0.05 <0.1 <0.1 <0.05 <0.1 <0.1 <0.1 <0.18 <0.15 <0.1 <0.1 <5 <0.1 <0.15

4/28/2003 Filtered <5 17 J 0.41 J <0.1 <0.1 <0.05 <0.1 <0.1 <0.1 <0.18 <0.15 0.69 J <0.1 9 J 0.07 J <0.15 11/20/2003 Filtered <1.0 <1.0 <1.0 0.17 J <1.0 <1.0 <1.0 <0.20 <1.0 <1.0 <1.0 <1.0 <1.0 0.66 J 0.13 J <1.05/12/2004 Filtered <1.0 <1.0 1.8 <1.0 <1.0 <1.0 <1.0 <0.2 <1.0 <1.0 0.32J 2.3 <1.0 47 0.14J 0.2J11/9/2004 Filtered <1.0 <1.0 2 <1.0 <1.0 <1.0 <1.0 <0.20 <1.0 <1.0 0.63 J <1.0 <1.0 <1.0 <1.0 0.64 J5/12/2005 Filtered <0.94 <0.94 <0.94 <0.94 <0.94 <0.94 <0.94 <0.19 <0.94 <0.94 <0.94 NA <0.94 NA 0.11 J <0.948/2/2006 Filtered 4.7 21 <1.0 <1.0 <1.0 <1.0 <1.0 <0.20 <1.0 <1.0 <1.0 8.1 <1.0 26 <1.0 <1.0

12/19/2006 Filtered <1.0 4.0 <1.0 <1.0 <1.0 <1.0 <1.0 <0.20 <1.0 <1.0 <1.0 <1.0 <1.0 1.8 <1.0 <1.06/26/2007 Filtered 3.3 3.1 0.35 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 2.2 <0.10 4.7 <0.10 <0.1011/15/2007 Filtered 0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 0.16 <0.11 <0.114/22/2008 Filtered 5 4.9 0.99 <0.51 <0.51 <0.51 <0.51 <0.51 <0.51 <0.51 <0.51 3.5 <0.51 40 <0.51 <0.5111/6/2008 Filtered 3.9 6.4 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 2.2 <1.0 100 <1.0 <1.04/8/2009 Filtered 13 16 <5.1 <5.1 <5.1 <5.1 <5.1 <5.1 <5.1 <5.1 <5.1 11 <5.1 460 <5.1 <5.1

10/13/2009 Filtered 1.3 1.1 0.13 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 0.40 <0.10 3.0 <0.10 <0.10MW-WAT1-4 3/27/2001 Filtered <2 30 6.3 9.7 8.5 <1 <2 9.9 7.5 <2 7.6 12 <2 94 9.6 4.6

10/26/2001 Filtered <0.11 0.56 0.18 <0.11 <0.11 <0.056 <0.11 <0.11 <0.11 <0.11 0.26 <0.11 <0.11 <0.17 <0.11 <0.17 4/23/2002 Filtered 24 10 1.1 <0.1 <0.1 <0.05 <0.1 <0.1 <0.1 <0.1 0.35 3.1 <0.1 8.6 0.4 <0.15 10/29/2002 Filtered <5 <2 <0.05 <0.1 <0.1 <0.05 <0.1 <0.1 <0.1 <0.18 <0.15 <0.1 <0.1 <5 <0.1 <0.15 4/28/2003 Filtered <5 <2 <0.05 <0.1 <0.1 0.03 J 0.2 0.1 <0.1 0.27 <0.15 <0.1 0.08 J <5 <0.1 <0.15 11/20/2003 Filtered <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <0.20 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.05/12/2004 Filtered <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <0.20 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.011/9/2004 Filtered <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <0.20 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.05/12/2005 Filtered <0.94 <0.94 <0.94 <0.94 <0.94 <0.94 <0.94 <0.19 <0.94 <0.94 <0.94 <0.94 <0.94 <0.94 <0.94 <0.948/2/2006 Filtered <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <0.20 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0

12/19/2006 Filtered <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <0.20 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.06/26/2007 Filtered <0.10 0.41 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.1011/15/2007 Filtered <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.114/22/2008 Filtered <0.10 0.36 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 4.3 <0.10 <0.1011/6/2008 Filtered <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.114/8/2009 Filtered 0.46 1.0 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 0.24 <0.10 <0.10

10/13/2009 Filtered <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10



Page 5 of 5

Well ID

Date Sampled

Acenaph-thene

Acenaph-thylene

Anthra-cene

Benzo(a)Anthra-

cene

Benzo(b)Fluoran-

thene

Benzo(k)Fluoran-

thene

Benzo(g,h,i)


Dibenz(a,h)

Anthra-cene


Indeno-(1,2,3-cd)-

pyreneNaph-


µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/LUnitsMW-WAT1-4

duplicate 4/23/2002 Filtered 18 11 0.95 <0.1 <0.1 <0.05 <0.1 <0.1 <0.1 <0.1 0.52 1.5 <0.1 6.2 0.29 <0.15

MW-WAT1-5 3/27/2001 Filtered <0.1 <0.1 <0.05 <0.1 <0.1 <0.05 <0.1 <0.1 <0.1 <0.1 <0.15 <0.1 <0.1 <0.15 <0.1 <0.15 10/26/2001 Filtered NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC4/23/2002 Filtered <0.1 <0.1 <0.05 <0.1 <0.1 <0.05 <0.1 <0.1 <0.1 <0.1 <0.15 <0.1 <0.1 <0.15 <0.1 <0.15 10/29/2002 Filtered NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC4/28/2003 Filtered <5 <2 <0.05 <0.1 <0.1 <0.05 <0.1 <0.1 <0.1 <0.18 <0.15 <0.1 <0.1 <5 <0.1 <0.15 11/20/2003 Filtered NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC5/12/2004 Filtered <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <0.20 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.011/9/2004 Filtered NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC5/12/2005 Filtered <0.94 <0.94 <0.94 <0.94 <0.94 <0.94 <0.94 <0.19 <0.94 <0.94 <0.94 <0.94 <0.94 0.56 J <0.94 <0.948/2/2006 Filtered <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <0.20 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0

12/19/2006 Filtered <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <0.20 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.06/26/2007 Filtered <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.1011/15/2007 Filtered <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.104/22/2008 Filtered <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.11 <0.1111/6/2008 Filtered <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.104/8/2009 Filtered <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10

10/12/2009 Filtered <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10MW-WAT1-6 10/13/2009 Filtered <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10MW-WAT1-7 10/13/2009 Filtered <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10 <0.10

--- --- --- --- --- --- --- 0.2 --- --- --- --- --- --- --- ---

Notes:Analytical results presented in bold exceed the MCL, if available

µg/L = micrograms per liter"<" = analyte not detected at or above laboratory reporting limit shown "J" = analyte detected at an estimated concentration between the laboratory method detection limit and the reporting limit"NC" = not collected due to insufficient water columnMCL = Maximum Contaminant Level based on Federal Drinking Water Standards (USEPA) (last updated June 2003) or California EPA (last updated September 2003); the more stringent MCL is shown--- = MCL has not been established for compoundSource: modified from ENV America (2005) and Shaw (2003)

PAHs = polycyclic aromatic hydrocarbons

Drinking Water MCL (ug/L)

Table 2-3BSummary of VOC, TPH, Metal

and Other Constituent Concentrations in Groundwater Samples Former Watsonville-1 MGP Site

Watsonville, California

Page 1 of 5

Benzene Toluene EthylbenzeneTotal

Xylenes* MTBE TPHg TPHd TPHmo Arsenic ** Hexavalent Chromium

Ammonia(as Nitrogen)

Total Cyanide Phenolics

µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/LMW-WAT1-1 6/24/1991 <1 <1 <1 1.4 --- <50 <50 <500 --- --- --- <10 <50

10/17/1997 <0.5 <0.5 <0.5 <0.5 --- <50 <50 <500 --- --- --- <10 <5 4/16/1998 <0.5 <0.5 <0.5 <0.5 --- <50 <50 <500 --- --- --- 40 <5 6/19/1998 <0.5 <0.5 <0.5 <0.5 --- <50 <50 <500 --- --- --- <10 <50

10/16/1998 <0.5 <0.5 <0.5 <0.5 <5 <50 57 <500 --- --- --- <10 <5 4/15/1999 <0.5 <0.5 <0.5 <0.5 <5 <50 <50 <500 --- --- --- <10 <5

10/26/1999 <0.5 <0.5 <0.5 <0.5 7.6 <50 <50 <300 --- --- --- <10 <50 4/13/2000 <0.5 <0.5 <0.5 <0.5 <5 <50 <50 <500 --- --- --- <5 11010/5/2000 <0.5 <0.5 <0.5 <0.5 <5 <50 <50 <500 --- --- --- <10 <100 3/14/2001 NC NC NC NC NC NC NC NC NC NC NC NC NC3/27/2001 <0.5 <0.5 <0.5 <0.5 <5 140 <50 <500 --- --- --- <5 <100

10/26/2001 <0.5 <0.5 <0.5 <0.5 <5 <50 <50 <500 --- --- --- --- ---4/23/2002 <0.5 <0.5 <0.5 <0.5 <5 <50 <50 <500 --- <10 130 <10 ---

10/29/2002 <0.5 <0.5 <0.5 <1.5 UJ --- <50 UJ <500 <500 <5 --- <110 <24 ---4/28/2003 <0.5 <0.5 <0.5 <1.5 UJ <5 <50 <480 <480 <5 --- 2,030 <21 ---

11/20/2003 <0.30 <0.30 <0.30 <0.30 <5.0 <50 <50 <250 <15 --- <100 <50 ---5/12/2004 <0.30 <0.30 <0.30 <0.60 <5.0 <50 <50 <250 <15 --- <100 <50 ---11/9/2004 0.24 J <0.30 <0.30 <0.30 <5.0 <50 <50 <250 <10 --- <100 <50 ---5/12/2005 <0.30 0.53 <0.30 <0.30 <5.0 <50 <50 <250 <10 --- <100 <50 ---8/2/2006 <0.30 <0.30 <0.30 <0.60 <5.0 <50 <50 <250 <10.0 --- <100 <50 ---

12/19/2006 <0.50 <0.50 <0.50 <1.0 <5.0 <50 <50 <250 <10.0 --- <100 <50 ---6/26/2007 <0.50 <0.50 <0.50 <1.0 <0.50 <50 <50 <500 <5.0 --- <200 <10 ---

11/15/2007 <0.50 <0.50 <0.50 <1.0 <0.50 <50 <50 <500 <5.0 --- <200 <10 ---4/22/2008 <0.50 <0.50 <0.50 <1.0 <0.50 <50 <50 <500 <5.0 --- <200 <10 ---11/6/2008 <0.50 <0.50 <0.50 <1.0 <0.50 <50 66 UN <500 9.2 --- <200 <10 ---4/8/2009 <0.50 <0.50 <0.50 <1.0 <0.50 <50 <50 <300 <9.5 --- <200 <10 ---

10/12/2009 <0.50 <0.50 <0.50 <1.0 <0.50 <50 <52 <310 <10 --- <200 <10 ---MW-WAT1-2 6/24/1991 2.3 2.2 2.1 12 --- 360 60 <500 --- --- --- 40 <50

10/17/1997 <0.5 <0.5 <0.5 <0.5 --- <50 <62 <620 --- --- --- 130 <5 4/16/1998 <0.5 <0.5 <0.5 <0.5 --- 11 120 <500 --- --- --- 210 76/19/1998 <0.5 <0.5 <0.5 <0.5 --- <50 <50 <500 --- --- --- 87 <50

10/16/1998 NC NC NC NC NC NC NC NC NC NC NC NC NC4/15/1999 <0.5 <0.5 <0.5 <0.5 <5 <50 <50 <500 --- --- --- 74.9 <50

10/26/1999 NC NC NC NC NC NC NC NC NC NC NC NC NC4/13/2000 <0.5 <0.5 <0.5 <0.5 <5 <50 <50 <500 --- --- --- <5 10010/5/2000 NC NC NC NC NC NC NC NC NC NC NC NC NC

Metals

Units

Other Constituents

Well ID Date Sampled

Volatile Organic Compounds Total Petroleum Hydrocarbons




Page 2 of 5





µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L µg/L

Metals

Units

Other Constituents



MW-WAT1-2 3/14/2001 NC NC NC NC NC NC NC NC NC NC NC NC NC(continued) 3/27/2001 <0.5 <0.5 <0.5 <0.5 <5 <50 56 <500 --- --- --- <5 <100

10/26/2001 NC NC NC NC NC NC NC NC NC NC NC NC NC4/23/2002 NC NC NC NC NC NC NC NC NC NC NC NC NC

10/29/2002 NC NC NC NC NC NC NC NC NC NC NC NC NC4/28/2003 NC NC NC NC NC NC NC NC NC NC NC NC NC

11/20/2003 <0.30 <0.30 <0.30 <0.30 <5.0 <50 140 <250 --- --- <100 --- ---5/12/2004 <0.30 <0.30 <0.30 <0.60 <5.0 <50 <50 <250 <15 --- <100 190 ---11/9/2004 <0.30 0.27 J <0.30 0.45 <5.0 <50 <50 <250 NC --- NC <50 ---5/12/2005 <0.30 0.57 <0.30 <0.30 <5.0 <50 110 <250 <10 --- 1,700 100 ---8/2/2006 <0.30 <0.30 <0.30 <0.60 <5.0 <50 <50 <250 <10.0 --- 350 81 ---

12/19/2006 <0.50 <0.50 <0.50 <1.0 <5.0 <50 NC NC NC --- NC NC ---6/26/2007 <0.50 <0.50 <0.50 <1.0 <0.50 <50 150 <500 <5.0 --- 1,300 220 ---

11/15/2007 <0.50 <0.50 <0.50 <1.0 <0.50 <50 NC NC NC NC NC NC ---4/22/2008 <0.50 <0.50 <0.50 <1.0 <0.50 <50 160 <500 <5.0 --- 1,900 220 ---11/6/2008 <0.50 <0.50 <0.50 <1.0 <0.50 <50 200 <500 <5.0 --- <200 300 ---4/8/2009 < 0.50 <0.50 <0.50 <1.0 <0.50 <50 <50 <300 <9.5 --- <200 100 ---

10/13/2009 <0.50 <0.50 <0.50 <1.0 <0.50 <50 NC NC NC --- NC NC ---MW-WAT1-3 6/24/1991 140 350 270 730 --- 900 510 800 --- --- --- <10 350

10/17/1997 8.8 49 8.7 100 --- 470 560 <570 --- --- --- 140 114/16/1998 18 130 130 420 --- 2,100 4,900 <500 --- --- --- 30 616/19/1998 7.6 81 47 190 --- 1,500 2,000 670 --- --- --- 24 69

10/16/1998 1.2 6.9 2.4 12 <5 73 170 <500 --- --- --- <10 <5 4/15/1999 25 310 120 740 <50 2,800 3,100 <500 --- --- --- 18 110

10/26/1999 2.3 24 9.3 39 4.3 300 150 <290 --- --- --- 10 <50 4/13/2000 33 360 110 650 <25 2,800 6,500 <500 --- --- --- <5 35010/5/2000 <0.5 5.2 1.2 6 <5 <50 160 <500 --- --- --- 20 <100 3/14/2001 NC NC NC NC NC NC NC NC NC NC NC NC NC3/27/2001 9.4 40 36 99 <25 900 1,500 <590 --- --- --- <5 <100

10/26/2001 <0.5 <0.5 <0.5 <0.5 <5 <50 <50 <500 --- --- --- --- ---4/23/2002 1.8 4.3 7.3 15 <5 240 460 <500 --- <10 4,100 6 ---

10/29/2002 1.5 <0.5 UJ <0.5 UJ 9.1 --- <50 UJ <500 UJ <500 8.3 --- 2,860 <24 ---4/28/2003 4.2 8.9 28.5 47 12 250 350 J <480 6 --- 3,490 <21 ---

11/20/2003 3.9 17 8.5 19.6 <10 110 160 <250 18.4 --- 2,500 <50 ---5/12/2004 3.3 7.3 16 27.2 <5.0 330 680 <250 <15 --- 4,700 <50 ---11/9/2004 0.53 0.68 0.88 1.93 <5.0 <50 69 <250 <10 --- 2,000 <50 ---




Page 3 of 5






Metals

Units

Other Constituents



MW-WAT1-3 5/12/2005 8.8 38 78 190 <10 1,800 3,000 1,000 <10 --- 6,700 <50 ---(continued) 8/2/2006 2.9 2.7 19 18.6 <5.0 520 1,200 610 <10.0 --- <100 <50 ---

12/19/2006 0.55 1.2 1.7 3.4 <5.0 <50 220 <250 <10.0 --- 4,600 <50 ---6/26/2007 2.5 2.9 12 11 <0.50 290 500 <500 5.0 --- 5,800 <10 ---

11/15/2007 0.70 2.4 2.1 4.7 <0.50 59 <50 <500 7.2 --- 2,000 <10 ---4/22/2008 8.6 23 49 45 <0.50 710 1,000 <500 5.1 --- 7,300 <10 ---11/6/2008 23 67 110 220 <0.50 1,500 1,300 < 500 6.7 --- 5,600 <10 ---4/8/2009 41 290 270 750 <2.5 4,200 5,800 <300 <9.5 --- 8,000 <10 ---

10/13/2009 <0.50 0.81 2.1 4.0 <0.50 <50 150 <310 <10 --- 3,600 13 ---MW-WAT1-3 4/16/1998 21 150 130 430 --- 2,200 3,400 <500 --- --- --- 20 43

duplicate 6/19/1998 8.6 92 55 230 --- 1,800 1,900 640 --- --- --- 230 <50 10/16/1998 1.2 7.6 2.6 12 <5 66 250 <500 --- --- --- 10 <5 4/15/1999 26 440 110 680 <50 3,000 3,300 <500 --- --- --- 16.6 110

10/26/1999 2.3 23 8.8 36 7 290 200 <300 --- --- --- 20 <50 4/13/2000 38 410 110 720 <25 3,300 5,600 <500 --- --- --- <5 36010/5/2000 0.57 5.7 1.6 5.9 <5 51 210 <500 --- --- --- <10 <100 3/27/2001 11 48 41 100 <25 1,100 1,700 <1,000 --- --- --- --- ---

10/26/2001 <0.5 <0.5 <0.5 <0.5 <5 <50 --- --- --- --- --- --- ---10/29/2002 1.8 <0.5 UJ <0.5 UJ 10 --- <50 UJ <500 UJ <500 9.8 --- 3,040 <24 ---4/28/2003 3.9 8.4 27.4 45 <5 230 400 J <480 5.4 --- 3,530 <21 ---

11/20/2003 2.9 15 7.5 16.6 <10 100 140 <250 24.2 --- 2,500 <50 ---5/12/2004 3.2 7.2 15 27 6.2 340 750 <250 <15 --- 4,600 <50 ---11/9/2004 0.44 0.58 0.73 1.48 <5.0 <50 <50 <250 <10 --- 2,000 <50 ---5/12/2005 8.8 39 79 192 <10 1,800 3,600 1,200 <10 --- 6,700 <50 ---8/2/2006 3 2.8 19 18.7 <5.0 600 930 420 <10.0 --- <100 <50 ---

12/19/2006 0.53 1.1 1.6 3.3 <5.0 <50 200 <250 <10.0 --- 4,000 <50 ---6/26/2007 2.1 2.6 11 9.4 <0.50 270 480 <500 <5.0 --- 5,800 12 ---

11/15/2007 0.74 2.4 2.2 4.9 <0.50 53 <50 <500 <5.0 --- 2,100 <10 ---4/22/2008 6.2 17 37 36 <0.50 520 910 <500 <5.0 --- 5,800 <10 ---11/6/2008 20 55 96 180 <0.50 1,100 1,400 <500 6.6 --- 5,600 < 10 ---4/8/2009 39 310 260 720 <2.5 4,100 5,800 <300 <9.5 --- 8,000 < 10 ---

10/13/2009 0.53 0.94 2.3 4.5 <0.50 <50 150 <310 <10 --- 3,400 13 ---MW-WAT1-4 3/27/2001 <0.5 1.1 1 18 <5 230 990 <500 --- --- --- <5 <100

10/26/2001 <0.5 <0.5 <0.5 <0.5 <5 <50 <50 <500 --- --- --- --- ---4/23/2002 <0.5 <0.5 <0.5 <0.5 <5 <50 180 <500 --- <10 1,400 <10 ---

10/29/2002 <0.5 <0.5 <0.5 <1.5 UJ --- <50 UJ <500 <500 <5 --- 402 <24 ---




Page 4 of 5






Metals

Units

Other Constituents



MW-WAT1-4 4/28/2003 <0.5 <0.5 UJ 1.4 <1.5 UJ 15 33 J <480 <480 <5 --- 664 <21 ---(continued) 11/20/2003 <0.30 <0.30 <0.30 <0.30 <5.0 <50 <50 <250 <15 --- <100 <50 ---

5/12/2004 <0.30 <0.30 <0.30 <0.60 <5.0 <50 <50 <250 <15 --- 1,800 <50 ---11/9/2004 0.54 <0.30 0.18 J 0.39 <5.0 <50 <50 <250 <10 --- <100 <50 ---5/12/2005 <0.30 0.78 <0.30 <0.30 6.1 <50 110 <250 <10 --- 280 <50 ---8/2/2006 <0.30 <0.30 <0.30 <0.60 <5.0 <50 150 <250 <10.0 --- <100 <50 ---

12/19/2006 <0.50 <0.50 <0.50 <1.0 <5.0 <50 <50 <250 <10.0 --- 560 <50 ---6/26/2007 <0.50 <0.50 <0.50 <1.0 <0.50 <50 350 660 <5.0 --- 1,600 <10 ---

11/15/2007 <0.50 <0.50 <0.50 <1.0 <0.50 <50 <50 <500 <5.0 --- 610 <10 ---4/22/2008 1.7 13 2.8 39 <0.50 190 620 <500 <5.0 --- 440 <10 ---11/6/2008 <0.50 <0.50 <0.50 <1.0 <0.50 <50 110 <500 <5.0 --- <200 37 ---4/8/2009 <0.50 1.0 <0.50 2.4 <0.50 <50 280 <300 <9.5 --- 750 UN <10 ---

10/13/2009 <0.50 <0.50 <0.50 <1.0 <0.50 <50 55 <310 <10 --- 1,200 <10 ---MW-WAT1-4

duplicate 4/23/2002 <0.5 <0.5 <0.5 <0.5 <5 <50 150 <570 --- <0.01 870 <10 ---

MW-WAT1-5 3/27/2001 <0.5 <0.5 <0.5 <0.5 <5 <50 <50 <500 --- --- --- <5 <100 10/26/2001 NC NC NC NC NC NC NC NC NC NC NC NC NC4/23/2002 <0.5 <0.5 <0.5 <0.5 <5 <50 <50 <500 --- <10 400 <10 ---

10/29/2002 NC NC NC NC NC NC NC NC NC NC NC NC NC4/28/2003 <0.5 <0.5 UJ <0.5 <1.5 UJ <5 <50 <480 <480 <5 --- <170 <21 ---

11/20/2003 NC NC NC NC NC NC NC NC NC NC NC NC NC5/12/2004 <0.30 <0.30 <0.30 <0.60 8.8 <50 <50 <250 <15 --- <100 <50 ---11/9/2004 NC NC NC NC NC NC NC NC NC NC NC NC NC5/12/2005 <0.30 <0.30 <0.30 <0.30 <5.0 <50 --- --- <10 --- <100 <50 ---8/2/2006 <0.30 <0.30 <0.30 <0.60 <5.0 <50 66 <250 <10.0 --- <100 <50 ---

12/19/2006 <0.50 <0.50 <0.50 <1.0 <5.0 <50 <50 <250 <10.0 --- <100 <50 ---6/26/2007 <0.50 <0.50 <0.50 <1.0 <0.50 <50 100 <500 <5.0 --- <200 <10 ---

11/15/2007 <0.50 <0.50 <0.50 <1.0 <0.50 <50 <50 <500 <5.0 --- <200 <10 ---4/22/2008 <0.50 <0.50 <0.50 <1.0 <0.50 <50 <50 <500 <5.0 --- <200 <10 ---11/6/2008 <0.50 <0.50 <0.50 <1.0 <0.50 <50 <50 <500 12 --- <200 <10 ---4/8/2009 <0.50 <0.50 <0.50 <1.0 <0.50 <50 <50 <300 <9.5 --- <200 <10 ---

10/12/2009 <0.50 <0.50 <0.50 <1.0 <0.50 <50 <51 <300 <10 --- <200 <10 ---MW-WAT1-6 10/13/2009*** <0.50 <0.50 <0.50 <1.0 <0.50 <50 1,800 / 68 1,000 / <300 <10 --- 510 <10 ---MW-WAT1-7 10/13/2009 <0.50 <0.50 <0.50 <1.0 <0.50 <50 <50 <300 <10 --- <200 <10 ---

1.0 150 300 1,750 13 --- --- --- 10 --- --- 150 ---Drinking Water MCL (ug/L)




Page 5 of 5

Notes:Analytical results presented in bold exceed the drinking water maximum contaminant level (MCL), if available * Total xylenes represents the sum of p/m-xylene and o-xylene; when both constituents were not detected, the higher reporting limit of the individual constituent is shown.** Beginning in 2003, all samples collected for arsenic analysis have been filtered upon collection.*** TPHd and TPHmo sample re-analyzed using silica-gel cleanup: initial TPHd and TPHmo concentration on left, and TPHd and TPHmo concentrations with silica-gel cleanup on right.

µg/L = micrograms per litermg/L = milligrams per liter "<" = analyte not detected at or above laboratory reporting limit shown"J" = analyte detected at an estimated concentration between the laboratory method detection limit and reporting limit "UJ" = analyte detected at an estimated concentration below the reporting limit, but was changed to non-detected above reporting limit based on detected concentration in associated QA/QC sample"UN" = analyte concentration represents a tentative non-detection at the reported result based on a detected concentration of the compound in an associated QA/QC sample"NC" = sample was not collected due to insufficient water column"MCL" = Maximum Contaminant Level based on Federal Drinking Water Standards (USEPA) (last updated May 2009) or California EPA (last updated May 2009); the more stringent MCL is shown --- = not analyzed / no data (MCL has not been established for compound)Source: modified from ENV America (2005) and Shaw (2003)

MTBE = methyl tert-butyl ether TPHg = total petroleum hydrocarbons (TPH) quantified as gasolineTPHd = TPH quantified as dieselTPHmo = TPH quantified as motor oil

Table 2-4Summary of TPHg and Detected VOCs in Soil Gas Samples


Page 1 of 4

Analytical MethodLocation ID SG-1

Sample Depth (feet bgs) 5 5 9 5 15 15 (dup) 5 15 5 15Sample Date 2/13/08 10/12/09 10/12/09 2/13/08 2/13/08 2/13/08 10/12/09 10/12/09 2/13/08 2/13/08

TPHg NA 6.17 1.49 NA NA NA ND (0.008) ND (0.008) NA NA1,2,4-Trimethylbenzene ND (0.007) 0.142 ND (0.008) ND (0.007) ND (0.007) ND (0.007) ND (0.008) ND (0.008) ND (0.007) ND (0.007)1,3,5-Trimethylbenzene ND (0.007) 0.021 ND (0.008) ND (0.007) ND (0.007) ND (0.007) ND (0.008) ND (0.008) ND (0.007) ND (0.007)

2-Butanone (MEK) NA NA NA NA NA NA NA NA NA NA4-Ethyltoluene NA NA NA NA NA NA NA NA NA NA

4-Isopropyltoluene ND (0.007) 0.043 ND (0.008) ND (0.007) ND (0.007) ND (0.007) ND (0.008) ND (0.008) ND (0.007) ND (0.007)Acetone NA NA NA NA NA NA NA NA NA NABenzene ND (0.007) ND (0.008) ND (0.008) ND (0.007) ND (0.007) ND (0.007) ND (0.008) ND (0.008) ND (0.007) ND (0.007)

Bromodichloromethane ND (0.007) 0.030 ND (0.008) ND (0.007) ND (0.007) ND (0.007) ND (0.008) ND (0.008) ND (0.007) ND (0.007)n-Butylbenzene ND (0.007) 0.059 ND (0.008) ND (0.007) ND (0.007) ND (0.007) ND (0.008) ND (0.008) ND (0.007) ND (0.007)

sec-Butylbenzene ND (0.007) 0.140 ND (0.008) ND (0.007) ND (0.007) ND (0.007) ND (0.008) ND (0.008) ND (0.007) ND (0.007)tert-Butylbenzene ND (0.007) ND (0.008) ND (0.008) ND (0.007) ND (0.007) ND (0.007) ND (0.008) ND (0.008) ND (0.007) ND (0.007)Carbon disulfide NA NA NA NA NA NA NA NA NA NA

Carbon tetrachloride ND (0.007) ND (0.008) ND (0.008) ND (0.007) ND (0.007) ND (0.007) ND (0.008) ND (0.008) ND (0.007) ND (0.007)Chloroform ND (0.007) 0.384 ND (0.008) ND (0.007) ND (0.007) ND (0.007) ND (0.008) ND (0.008) ND (0.007) ND (0.007)

Dichlorodifluoromethane ND (0.007) ND (0.008) ND (0.008) ND (0.007) ND (0.007) ND (0.007) ND (0.008) ND (0.008) ND (0.007) ND (0.007)Ethylbenzene ND (0.007) 0.018 ND (0.008) ND (0.007) ND (0.007) ND (0.007) ND (0.008) ND (0.008) ND (0.007) ND (0.007)

Isopropylbenzene ND (0.007) 0.025 ND (0.008) ND (0.007) ND (0.007) ND (0.007) ND (0.008) ND (0.008) ND (0.007) ND (0.007)Methylene chloride ND (0.007) ND (0.008) ND (0.008) ND (0.007) ND (0.007) ND (0.007) ND (0.008) ND (0.008) ND (0.007) ND (0.007)

Naphthalene ND (0.007) ND (0.008) ND (0.008) ND (0.007) ND (0.007) ND (0.007) ND (0.008) ND (0.008) ND (0.007) ND (0.007)n-Propylbenzene ND (0.007) ND (0.008) ND (0.008) ND (0.007) ND (0.007) ND (0.007) ND (0.008) ND (0.008) ND (0.007) ND (0.007)

Styrene ND (0.007) ND (0.008) ND (0.008) ND (0.007) ND (0.007) ND (0.007) ND (0.008) ND (0.008) ND (0.007) ND (0.007)Toluene 0.013 ND (0.008) 0.403 0.015 0.037 0.020 ND (0.008) ND (0.008) 0.042 0.083

Trichlorofluoromethane ND (0.007) ND (0.008) ND (0.008) ND (0.007) ND (0.007) ND (0.007) ND (0.008) ND (0.008) ND (0.007) ND (0.007)Xylenes (total) ND (0.007) 0.202 0.085 ND (0.007) ND (0.007) ND (0.007) ND (0.008) ND (0.008) ND (0.007) ND (0.007)Other VOCs ND ND ND ND ND ND ND ND ND ND

Notes:Analytical results are presented in micrograms per liter (ug/L)."ND<" indicates the consitituent was not detected at or above the laboratory reporting limit.On 2/12/08 and 2/13/08, a purge test was conducted on soil gas samples collected from 15 feet at probe SG-7. Sample volumes were collected at 1, 3 and 7 volumes (1P, 3P and 7P, respectively). The highest concentrations for the compounds of interest were detected

in the 1-purge-volume sample. As a result, soil gas samples from all remaining probes were collected after purging 1 volume of air. On 10/12/09, a purge test was conducted on soil gas samples collected from 5 feet and 15 feet at probe SG-6A. Sample volumes were collected at 1, 3 and 10 volumes (1P, 3P and 10P, respectively). The highest concentrations for the compounds of interest were detected

in the 3-purge-volume and 10-purge-volume samples, respectively. As a result, soil gas samples from all remaining probes were collected after purging 3 volumes of air for the 5-foot samples and 10 volumes of air for the 9-foot or 15-foot samples.

dup = duplicate sampleNA = not analyzedTPHg = total petroleum hydrocarbons quantified as gasolineVOC = volatile organic compoundUSEPA = United States Environmental Protection AgencyJA = estimated value because of interference by non-target compounds J = estimated value; analyte detected at a concentration less than the reporting limit and greater than or equal to the method detection limitUN = Result is estimated due to possible contamination in the trip blank. Result is less than five times the amount reported in the trip blank.

TPHg and VOCs including Naphthalene (USEPA Method 8260B)SG-1A SG-2 SG-2A SG-3



Page 2 of 4

Analytical MethodLocation ID

Sample Depth (feet bgs)Sample Date

TPHg1,2,4-Trimethylbenzene1,3,5-Trimethylbenzene

2-Butanone (MEK)4-Ethyltoluene

4-IsopropyltolueneAcetoneBenzene

Bromodichloromethanen-Butylbenzene

sec-Butylbenzenetert-ButylbenzeneCarbon disulfide

Carbon tetrachlorideChloroform

DichlorodifluoromethaneEthylbenzene

IsopropylbenzeneMethylene chloride

Naphthalenen-Propylbenzene

StyreneToluene

TrichlorofluoromethaneXylenes (total)Other VOCs

5 15 5 15 15 (dup) 5 15 5 15 5 15 5 1510/12/09 10/12/09 2/12/08 2/12/08 2/12/08 10/12/09 10/12/09 2/13/08 2/12/08 10/12/09 10/12/09 2/12/08 2/12/08

6.32 ND (0.008) NA NA NA 15.4 6,170 NA NA 0.955 17.5 NA NAND (0.008) ND (0.008) ND (0.018) 1.13 1.23 0.147 114 ND (0.007) ND (0.018) 0.119 0.046 ND (0.018) ND (0.018)ND (0.008) ND (0.008) ND (0.018) 1.24 1.18 0.067 157 ND (0.007) ND (0.018) 0.027 0.052 ND (0.018) ND (0.018)

NA NA NA NA NA NA NA NA NA NA NA NA NANA NA NA NA NA NA NA NA NA NA NA NA NA

ND (0.008) ND (0.008) ND (0.018) ND (0.07) ND (0.07) 0.078 ND (0.08) ND (0.007) ND (0.018) 0.044 ND (0.008) ND (0.018) ND (0.018)NA NA NA NA NA NA NA NA NA NA NA NA NA

ND (0.008) ND (0.008) 0.571 41.5 43.7 ND (0.008) 26.8 ND (0.007) 0.214 ND (0.008) 0.109 0.608 19.1ND (0.008) ND (0.008) ND (0.018) ND (0.07) ND (0.07) ND (0.008) ND (0.08) ND (0.007) ND (0.018) ND (0.008) ND (0.008) ND (0.018) ND (0.018)ND (0.008) ND (0.008) ND (0.018) ND (0.07) ND (0.07) 0.06 ND (0.08) ND (0.007) ND (0.018) 0.057 ND (0.008) ND (0.018) ND (0.018)ND (0.008) ND (0.008) ND (0.018) ND (0.07) ND (0.07) 0.145 ND (0.08) ND (0.007) ND (0.018) ND (0.008) ND (0.008) ND (0.018) ND (0.018)ND (0.008) ND (0.008) ND (0.018) ND (0.07) ND (0.07) ND (0.008) 5.66 ND (0.007) ND (0.018) 0.102 0.105 ND (0.018) ND (0.018)

NA NA NA NA NA NA NA NA NA NA NA NA NAND (0.008) ND (0.008) ND (0.018) ND (0.07) ND (0.07) ND (0.008) ND (0.08) ND (0.007) ND (0.018) ND (0.008) ND (0.008) ND (0.018) ND (0.018)ND (0.008) ND (0.008) ND (0.018) ND (0.07) ND (0.07) ND (0.008) ND (0.08) ND (0.007) ND (0.018) 0.142 0.009 ND (0.018) ND (0.018)ND (0.008) ND (0.008) ND (0.018) ND (0.07) ND (0.07) ND (0.008) ND (0.08) ND (0.007) ND (0.018) ND (0.008) ND (0.008) ND (0.018) ND (0.018)ND (0.008) ND (0.008) 0.525 26.5 27.3 0.671 283 ND (0.007) ND (0.018) ND (0.008) 0.124 0.940 10.4ND (0.008) ND (0.008) ND (0.018) 1.65 0.824 0.03 25.8 ND (0.007) ND (0.018) 0.021 0.640 ND (0.018) 0.441ND (0.008) ND (0.008) ND (0.018) ND (0.07) ND (0.07) ND (0.008) ND (0.08) ND (0.007) ND (0.018) ND (0.008) ND (0.008) ND (0.018) ND (0.018)ND (0.008) ND (0.008) ND (0.018) ND (0.07) ND (0.07) ND (0.008) 85.8 ND (0.007) ND (0.018) ND (0.008) 0.035 ND (0.018) ND (0.018)ND (0.008) ND (0.008) ND (0.018) ND (0.07) ND (0.07) ND (0.008) ND (0.08) ND (0.007) ND (0.018) ND (0.008) ND (0.008) ND (0.018) ND (0.018)ND (0.008) ND (0.008) ND (0.018) ND (0.07) ND (0.07) ND (0.008) ND (0.08) ND (0.007) ND (0.018) ND (0.008) ND (0.008) ND (0.018) ND (0.018)

3.12 ND (0.008) 9.45 445 501 0.295 1,320 0.059 1.56 0.122 0.211 5.97 99.3ND (0.008) ND (0.008) ND (0.018) ND (0.07) ND (0.07) ND (0.008) ND (0.08) ND (0.007) ND (0.018) ND (0.008) ND (0.008) ND (0.018) ND (0.018)ND (0.008) ND (0.008) 3.16 130 145 1.05 2,170 ND (0.007) ND (0.018) 0.321 0.527 6.00 24.7

ND ND ND ND ND ND ND ND ND ND ND ND ND





TPHg and VOCs including Naphthalene (USEPA Method 8260B)SG-3A SG-4 SG-4A SG-5 SG-5A SG-6



Page 3 of 4












StyreneToluene


5 15 5 15 5 15 5 5 (dup) 15 5 15 15 (dup)10/12/09 10/12/09 2/12/08 2/12/08 10/12/09 10/12/09 10/12/09 10/12/09 10/12/09 10/12/09 10/12/09 10/12/09

6.65 946 NA NA ND (0.008) ND (0.008) 0.180 0.195 6.2 1.26 4.03 4.550.342 11.1 ND (0.018) ND (0.018) ND (0.008) ND (0.008) 0.058 0.070 ND (0.008) 0.113 ND (0.02) ND (0.008)0.188 29.6 ND (0.018) ND (0.018) ND (0.008) ND (0.008) ND (0.008) ND (0.008) ND (0.008) 0.030 ND (0.02) ND (0.008)

NA NA NA NA NA NA NA NA NA NA NA NANA NA NA NA NA NA NA NA NA NA NA NA

0.057 ND (0.02) ND (0.018) ND (0.018) ND (0.008) ND (0.008) 0.048 0.042 ND (0.008) 0.090 ND (0.02) ND (0.008)NA NA NA NA NA NA NA NA NA NA NA NA

ND (0.008) 3.54 0.051 1.19 ND (0.008) ND (0.008) ND (0.008) ND (0.008) ND (0.008) 0.050 ND (0.02) ND (0.008)ND (0.008) ND (0.02) ND (0.018) ND (0.018) ND (0.008) ND (0.008) ND (0.008) ND (0.008) ND (0.008) ND (0.008) ND (0.02) ND (0.008)

0.076 ND (0.02) ND (0.018) ND (0.018) ND (0.008) ND (0.008) ND (0.008) ND (0.008) ND (0.008) 0.060 ND (0.02) ND (0.008)0.301 ND (0.02) ND (0.018) ND (0.018) ND (0.008) ND (0.008) 0.073 0.083 ND (0.008) 0.120 ND (0.02) ND (0.008)

ND (0.008) 0.995 ND (0.018) ND (0.018) ND (0.008) ND (0.008) ND (0.008) ND (0.008) ND (0.008) ND (0.008) ND (0.02) ND (0.008)NA NA NA NA NA NA NA NA NA NA NA NA

ND (0.008) ND (0.02) ND (0.018) ND (0.018) ND (0.008) ND (0.008) ND (0.008) ND (0.008) ND (0.008) ND (0.008) ND (0.02) ND (0.008)ND (0.008) ND (0.02) ND (0.018) ND (0.018) ND (0.008) ND (0.008) ND (0.008) ND (0.008) ND (0.008) ND (0.008) ND (0.02) ND (0.008)ND (0.008) ND (0.02) ND (0.018) ND (0.018) ND (0.008) ND (0.008) ND (0.008) ND (0.008) ND (0.008) ND (0.008) ND (0.02) ND (0.008)

0.649 43.5 1.26 0.358 ND (0.008) ND (0.008) ND (0.008) ND (0.008) ND (0.008) 0.201 ND (0.02) ND (0.008)0.095 9.87 ND (0.018) ND (0.018) ND (0.008) ND (0.008) ND (0.008) ND (0.008) ND (0.008) 0.024 ND (0.02) ND (0.008)

ND (0.008) ND (0.02) ND (0.018) ND (0.018) ND (0.008) ND (0.008) ND (0.008) ND (0.008) ND (0.008) ND (0.008) ND (0.02) ND (0.008)ND (0.008) 19.7 ND (0.018) ND (0.018) ND (0.008) ND (0.008) ND (0.008) ND (0.008) ND (0.008) ND (0.008) ND (0.02) ND (0.008)

0.021 ND (0.02) ND (0.018) ND (0.018) ND (0.008) ND (0.008) ND (0.008) ND (0.008) ND (0.008) ND (0.008) ND (0.02) ND (0.008)ND (0.008) ND (0.02) ND (0.018) ND (0.018) ND (0.008) ND (0.008) ND (0.008) ND (0.008) ND (0.008) ND (0.008) ND (0.02) ND (0.008)

0.141 70.0 2.01 6.97 ND (0.008) ND (0.008) ND (0.008) ND (0.008) ND (0.008) 0.129 ND (0.02) ND (0.008)ND (0.008) ND (0.02) ND (0.018) ND (0.018) ND (0.008) ND (0.008) ND (0.008) ND (0.008) ND (0.008) ND (0.008) ND (0.02) ND (0.008)

1.14 258 16.0 1.10 ND (0.008) ND (0.008) ND (0.007) ND (0.007) ND (0.007) 0.291 0.205 0.191ND ND ND ND ND ND ND ND ND ND ND ND





TPHg and VOCs including Naphthalene (USEPA Method 8260B)SG-8 SG-9 SG-10SG-6A SG-7



Page 4 of 4












StyreneToluene


SG-1A SG-2 SG-4 SG-4A SG-6A5 15 5 15 5

10/12/09 2/13/08 2/12/08 10/12/09 10/12/098.5 NA NA 6,200 19

ND (0.0064) 0.0051 0.033 110 0.054ND (0.0054) ND (0.0024) 0.025 70 0.093

0.0083 J 0.0055 ND (0.0058) ND (3.0) 0.011 JND (0.0049) 0.0040 0.046 140 0.088

NA NA NA NA NA0.036 0.032 0.026 ND (3.0) ND (0.0069)

ND (0.0048) 0.030 0.0093 20 0.016ND (0.0067) ND (0.002) ND (0.004) ND (3.4) ND (0.0078)

NA NA NA NA NANA NA NA NA NANA NA NA NA NA

ND (0.0062) 0.019 0.0084 ND (3.1) 0.019 JND (0.0063) ND (0.0019) ND (0.0038) ND (3.2) ND (0.0073)

0.56 ND (0.0015) ND (0.003) ND (2.5) 0.010 JND (0.0074) 0.0038 ND (0.003) ND (3.7) ND (0.0086)

0.0051 J 0.0044 0.015 180 0.082NA NA NA NA NA

0.011 UN 0.0016 ND (0.002) ND (1.8) 0.0096 UNND (0.016) ND (0.0026) ND (0.0052) ND (7.9) 0.023 J

NA NA NA NA NAND (0.0043) 0.0035 JA 0.03 JA 63 ND (0.0049)

0.013 0.041 0.096 810 0.052ND (0.0056) 0.0027 ND (0.0044) ND (2.8) ND (0.0065)

0.027 0.024 0.430 1,800 0.40ND ND ND ND ND





TPHg and VOCs including Naphthalene (USEPA Method TO-15)

Table 4-1

Potentially Applicable or Relevant and Appropriate Requirements List Former Watsonville-1 MGP Site


Page 1 of 3

Standard, Requirement, Criteria, Limitation

Citation

Description

Type of ARARs

Federal Clean Air Act 42 United States Code (USC)

7401-7642 Emission Standards from stationary and mobile sources Chemical

Hazardous Waste Identification 40 Code of Federal Regulations (CFR) 261.24

Establishes criteria to determine whether solid waste exhibits hazard characteristics of toxicity

Chemical

National Primary and Secondary Ambient Air Quality Standards (NAAQS)

40 CFR Part 150 Establishes NAAQS for criteria pollutants: particulate matter (PM10), sulfur dioxide, carbon monoxide, nitrogen dioxide, ozone, and lead.

Chemical

Hazardous Materials Transportation, Marking, Labeling and Placarding

US Department of Transportation (DOT) 49 USC 1802, et seq. and 49 CFR 171 & 172

Provides standards for marking, labeling, placarding, and transportation of waste.

Action

Clean Water Act 33 USC 1251-1387 Regulates the discharge of nontoxic and toxic pollutants into surface water by municipal sources, industrial sources, and other specific and nonspecific sources

Chemical

Occupational Health and Safety 29 CFR 1910.120 Establishes requirements for health and safety training Action

USEPA “Superfund” Program Comprehensive, Environmental Response, Compensation, and Liability Act (CERCLA) as amended by the Superfund Amendments and Reauthorization Act of 1986 (SARA) (US 1986). Part of the National Contingency Plan (NCP; US 1994)

CERCLA provides federal authority to respond to abandoned or uncontrolled hazardous waste disposal sites as well as to incidents involving hazardous substances. CERCLA provides for liability, compensation, cleanup, and emergency response in connection with cleanup of these “superfund” sites.

Chemical/ Action

Resource Conservation and Recovery Act (RCRA)

42 USC 6901 et seq. 40 CFR 260-268

Classifies and regulates hazardous wastes and facilities which treat, store and dispose of hazardous materials.

Chemical/ Action

Health Risk Assessment US EPA, Risk Assessment Guidance for Superfund, 1989

Guidance and framework to assess health risk To Be Considered

State and Local Determination of Characteristic Wastes 22 California Code of Regulations (CCR)

66261.24 Establishes criteria for identifying characteristic wastes. Chemical

Ambient Air Quality Standards Health and Safety Code (H&SC) Section 39000-44071

Establishes standards for emissions of chemical vapors and dust Chemical

Table 4-1



Page 2 of 3


Citation

Description

Type of ARARs

Hazardous Waste Control Act H&SC Chapter 6.5, Sec. 25100-25250.26 Establishes hazardous waste control measures Action Hazardous Waste Generator Requirements

22 CCR 66262.11 et seq. Establishes standards applicable to generators of hazardous waste Action

Occupational Health and Safety 8 CCR Sections 1500, 2300, and 3200 et seq.

Establishes standards for working conditions and employees matter; and notification requirements.

Action

Environmental Impact Review Public Resources Code Section 21000-21177

Mandates environmental impact review of projects approved by governmental agencies

Action

Hazardous Substances Account Act H&SC, Chapter 6.8, Sections 25300-25395.15

Establishes site mitigation and cost recovery programs Action

DTSC Site Mitigation Program Policies and Procedures

DTSC Applicable policies, procedures, management memos and related guidance documents.

Action

Standards for Discharges of Waste to Land

Title 23 CCR, Division 3, Chapter 15, Article 1, Section 2511(d) and Articles 2, 8, and 9.

Exempts from Chapter 15 any actions taken by a public agency to cleanup waste, provided that waste removed from place of release shall be discharged according to the Article 2.

Action

Monterey Bay Unified Air Pollution Control District Mulford-Carrell Air Resources Act

Health and Safety Code Section 39000 et seq.

Establishes fugitive dust/particulate emissions requirements Action

Porter-Cologne Water Quality Control Act

Title 23 CCR, Division 3, Chapter 15, Article 2; Waste Classification and Management

Establishes/defines procedures and criteria for classification and management of waste.

Chemical/ Action

California Safe Drinking Water and Toxic Enforcement Act

Title 22 CCR, Division 4, Article 4, Section 64431

Establishes criteria for levels of constituents in drinking water (i.e. sets state maximum contaminant limits [MCLs])

Chemical/ Action

Determination of Hazardous Waste 22 CCR 66260.1 et seq. Establishes criteria for determining waste classification for the purposes of transportation and disposal of wastes

Chemical/ Action

Land Disposal Restrictions 22 CCR Chapter 18 Identifies hazardous waste restricted from land disposal unless specific treatment standards are met

Chemical/ Action

Land Use Covenants 22 CCR Chapter 39, Division 4.5, Section 67391.1

Specifies that a land use covenant imposing appropriate limitations on land use shall be executed and recorded when hazardous materials, hazardous wastes or constituents, or hazardous substances will remain at the property at levels which are not suitable for unrestricted use of the land.

Action

Table 4-1



Page 3 of 3


Citation

Description

Type of ARARs

City/County Permits City of Watsonville Santa Cruz County

Site-specific grading/backfill and drill permits, noise ordinances, and discharges to publicly owned treatment works (POTWs)

To Be Considered

Note: ARAR = Applicable or Relevant and Appropriate Requirement

of 4

TABLE 5-1A

Summary of Technology Types and Process Options Screening for Soil Former Watsonville-1 MGP Site


General Response

Action

Technology Type/Process

Options

Description

Screening Comments

Retained for

Further Analyses No Action

• None

Site is not changed.

Required for consideration by National Contingency Plan (NCP).

Yes


• Deed Restriction • Fence

Deed restriction on property prohibiting Site activities that could disturb underlying contaminated materials, or limit land use to certain conditions. Fencing around site to limit access.

Potentially applicable. Would not reduce or control migration of contaminants. Would require landowner’s approval. The site is an operating restaurant that utilizes the area surrounding the building for access and parking.

Yes

No

Containment

• Capping

- Earthen Cap

- Asphalt/Concrete Cap

- Vegetative Cap

Application of a layer of clean soil over areas of contamination. Installation of an asphalt or concrete layer over areas of contamination. Plant and maintain vegetation over areas of contamination.

Minimizes exposure to impacted surface soil and control of surface runoff. Easily maintained. Potentially applicable. Minimizes exposure to surface soil. More costly to install and maintain. Proposed site use will include a parking lot with planters along the perimeter. A vegetative cap would not be appropriate for the parking area and would be aesthetically less pleasing than a soil cap with landscaping similar to existing conditions.

Yes

Yes

No

of 4

TABLE 5-1A Summary of Technology Types and Process Options Screening for Soil

Former Watsonville-1 MGP Site Watsonville, California

General Response

Action


Options

Description

Screening Comments

Retained for

Further Analyses In-situ Treatment

• Vapor Extraction • Bioventing

Vapor extraction to strip soils contaminated with volatile organic compounds. Off-gases will be treated before release into the atmosphere. Injection of oxygen and nutrients to enhance the natural microbial degradation process which lead to breakdown and disintegration of the organic compounds.

Not proven to be effective for treatment of PAHs. Not proven to be effective for treatment of PAHs.

No

No

Excavation

• Excavation and Earthmoving

Excavation of soil by conventional equipment.

Excavation of soil for either offsite disposal or ex-situ treatment.

Yes

of 4



General Response

Action


Options

Description

Screening Comments

Retained for

Further Analyses Treatment/ Disposal

• Thermal Treatment

- Rotary Kiln

- Thermal Desorption

- Thermal Distillation • Physical Treatment

(Stabilization/Fixation) - Portland Cement Base - Silicate Base - Fly Ash Derivatives Base - Organophilic Clay Base

• Soil Washing

Combustion of soil in offsite incinerators. Volatilization of organics by low temperature heating. Volatilization of organics by high temperature heating. In-situ or ex-situ mixing with solidifying agents. Organic and inorganic contaminants are washed from soil by water and/or solvents.

Effective for wide range of organics. Closest permitted facility is in Texas. Cost far too high. Offsite treatment facilities or onsite treatment units are available. Effective for PAHs. Effective for PAHs. Treatment units are available. Cost is higher than thermal desorption treatment. No advantages over thermal desorption. Immobilizes organics into a monolithic chemical structure. Not proved to be effective for PAHs. Not effective for low-soluble PAHs.

No

Yes

No

No

No

of 4



General Response

Action


Options

Description

Screening Comments

Retained for

Further Analyses Treatment/ Disposal

• Biological Treatment

- Biodegradation

- Landfarming • Cold Mix Asphalt Processing • Offsite Disposal • Hot Air/Steam Stripping

Degradation of organics using microorganisms in an aerobic or anaerobic environment. Degradation of organics using microorganisms in an aerobic environment. Incorporation of petroleum hydrocarbon-laden soils into a cold mix asphalt which can be used for paving. Transportation of contaminated materials to a proper landfill and disposal of at the landfill. Injection of hot air or steam into ground to help remove volatile organic compounds.

Not demonstrated effective for treatment of PAHs. Not demonstrated to be effective for treatment of soils that are contaminated with PAHs. Large land area is required. Potentially effective for petroleum hydrocarbons. Would not reduce volume and toxicities of contaminants. Contaminants are removed and transferred to an appropriate offsite facility. Would not reduce volume and toxicity. Not fully demonstrated to be effective on semivolatile organic compounds.

No

No

No

Yes

No

of 1

Table 5-1B

Summary of Technology Types and Process Options Screening For Soil Gas Former Watsonville-1 MGP Site


General Response

Action


Options

Description

Screening Comments

Retained for

Further Analyses

No Action

• None



Yes


• Deed restriction

Deed restriction on property limiting land use to certain conditions (i.e., no buildings on eastern portion of site to avoid vapor intrusion of contaminated soil gas into indoor air)

Potentially applicable. Would not reduce or control migration of contaminants. Would require landowner’s approval.

Yes

Soil Gas Monitoring

• Semi-annual monitoring

Soil gas sampling and analysis to verify contaminated soil gas not migrating towards building

Viable option, albeit relatively long-term.

Yes


• Pumping vadose soil gas wells

and treatment

Extraction of contaminated soil gas from pumping vadose soil gas wells located in area of impact. Soil gas treated onsite and discharged under permit.

Relatively costly and potentially ineffective in primary offsite areas where sources remain.

Yes

of 1

Table 5-1C

Summary of Technology Types and Process Options Screening For Groundwater Former Watsonville-1 MGP Site


General Response

Action


Options

Description

Screening Comments

Retained for

Further Analyses

No Action

• None



Yes

Monitoring and Natural Attenuation

• Semi-annual monitoring

Groundwater sampling and analyses to monitor natural biodegradation of contaminants.

Viable option, albeit relatively long-term.

Yes

Groundwater Extraction and Treatment

• Pumping wells & treatment • Trench recovery system and

treatment

Extraction of contaminated groundwater from pumping wells. Water treated onsite and discharged under permit. Extraction of contaminated groundwater from trench recovery system. Water treated onsite and discharged under permit.

Based on low hydraulic conductivity of the shallow aquifer, groundwater extraction and treatment is not considered practical.

No

Barrier Wall/Encapsulation

• Slurry wall • Sheet pile cut-off wall • Grout curtain

Installation of subsurface barrier to confine contaminants by surrounding contaminated groundwater.

Relatively high costs associated with construction and difficult to implement across multiple developed properties.

No

In-situ Bio-remediation

• Injection of nutrients and/or

oxygen

Introduction of compounds into the saturated zone to enhance biodegradation of hydrocarbons.

Relatively costly and potentially ineffective in areas beyond injection points, due to relatively cohesive saturated zone.

Yes

Removal of Contaminated Groundwater During Soil Excavation

• Groundwater pumping and

onsite or offsite treatment

Pumping of contaminated liquid from open excavation. Groundwater then treated onsite and discharged or transported offsite for treatment/disposal.

Groundwater recovery would be minimal under an excavation scenario.

No

of 1

Table 5-2A Soil General Response Actions and Technology Types/Process Options Retained for Further

Evaluation Former Watsonville-1 MGP Site Watsonville, California

General Response Actions

Technology Types/Process Options Retained Under Each

Response Action No Action

Required by NCP. Serves as Baseline

Institutional Control

Deed Restriction

Containment

Cap

Excavation/Disposal

Excavation and Offsite Disposal

Excavation/Treatment

Excavation and Thermal Desorption

of 1

Table 5-2B Soil Gas General Response Actions and Technology Types/Process Options Retained for Further

Evaluation Former Watsonville-1 MGP Site Watsonville, California

General Response Actions



Required by NCP. Serves as Baseline

Institutional Control

Deed Restriction


Semi-annual Soil Gas Monitoring


Vapor Extraction via Extraction Well Network and Carbon Adsorption Treatment

of 1

Table 5-2C

Groundwater General Response Actions and Technology Types/Process Options Retained for Further Evaluation

Former Watsonville-1 MGP Site Watsonville, California General Response Actions



Required by NCP. Serves as Baseline.


Semi-annual groundwater monitoring.

In situ Bioremediation Injection of oxygen and/or nutrients, monitoring.

Table 5-3APreliminary Remedial Cost Estimates for Soil Alternatives


Page 1 of 1

1. No Action 1 1 0 0 0

2. Cap, Institutional Controls & Focused Excavation1) Planning/Permitting/Mob/Demob 1 Est. 50,000 50,0002) Demo & Disposal 1 Est. 15,000 15,0003) Excavation, Loading, Transport, Disposal & Backfill 1 Est. 145,000 145,0004) Grading, Paving & Drainage 1 Est. 85,000 85,0005) Landscaping & Restoration 1 Est. 20,000 20,0006) Oversight/Management 1 Est. 135,000 135,0008) Confirmation Sampling & Completion Report 1 Est. 70,000 70,000 520,000

3. Excavation and Offsite Treatment1) Mob/Demob/Permitting/Demolition 1 Est. 85,000 85,0002) Removal & Loading of Soil 4,500 ton 45 202,5003) Transportation and Offsite Treatment (Non-Haz) 4,500 ton 125 562,5004) Backfilling with Clean Soil 3,400 ton 30 102,0005) Backfilling with Slurry 1,500 CY 100 150,0006) Soil Retainment System (shoring or equiv.) 1 Est. 200,000 200,0007) Design/Oversight/Management 1 Est. 250,000 250,0008) Fenceline Air Sampling 1 Est. 120,000 120,0009) Grading, Paving, Drainage & Restoration 1 Est. 85,000 85,00010) Confirmation Sampling & Closure Report 1 Est. 115,000 115,000 1,872,000

4. Excavation and Offsite Disposal1) Mob/Demob/Permitting/Demolition 1 Est. 85,000 85,0002) Removal & Loading of Soil 4,500 ton 45 202,5003) Transportation and Offsite Disposal (Non-Haz) 4,500 ton 100 450,0004) Backfilling with Clean Soil 3,400 ton 30 102,0005) Backfilling with Slurry 1,500 CY 100 150,0006) Soil Retainment System (shoring or equiv.) 1 Est. 200,000 200,0007) Design/Oversight/Management 1 Est. 250,000 250,0008) Fenceline Air Sampling 1 Est. 120,000 120,0009) Grading, Paving, Drainage & Restoration 1 Est. 85,000 85,00010) Confirmation Sampling & Closure Report 1 Est. 115,000 115,000 1,759,500

Quantity Unit Rate ($)

Present Worth

Subtotal ($)

Present Worth Total

($)Alternative

Table 5-3BPreliminary Remedial Cost Estimates for Soil Gas Alternatives


Page 1 of 1

1. No Action 1 1 0 0 0

2. Soil Gas Monitoring and Institutional Controls1) Monitoring and sampling (2)(4) 35 event 9,600 264,6002) Data Analyses and Evaluation 35 event 3,000 82,688 347,288

3. Soil Vapor Extraction and Vapor Treatment, Soil Gas Monitoring and Institutional Controls

1) Planning/Design/Permitting/Mob/Demob 1 Est. 65,000 65,000

2) Vapor Extraction Well Installation 1 Est. 55,000 55,0003) Vapor Collection and Treatment System Installation

1 Est. 95,000 95,000

4) Engineering/Oversight/Management 1 Est. 75,000 75,0005) Installation Startup Testing and Reporting 1 Est. 45,000 45,000

6) Monitoring and sampling (3)(4) 33 event 4,500 116,9447) Operation, Maintenance and Reporting of Vapor Treatment System

30 Years 25,000 590,625 1,042,569

Alternative

(2) Semi-annual sampling and monitoring for years 1 through 5 followed by annual monitoring for years 6 through 30.

(3) Semi-annual sampling and monitoring for years 1 through 3 followed by annual monitoring for years 4 through 30.

Notes:(1) Present worth adjustments made for future costs on items labeled with Note (4). Present worth adjustments calculated based on annual discount rate of 3.4%.

(4) Future costs adjusted for present worth [see Note (1)].

Quantity Unit Rate ($)Present(1)

Worth Subtotal

($)

Present Worth Total

($)

Table 5-3CPreliminary Remedial Cost Estimates for Groundwater Alternatives


Page 1 of 1

1. No Action 1 1 0 0 0

2. Monitored Natural Attenuation Groundwater Monitoring and Sampling (2) 35 event 13,000 358,313

Data Analyses, Evaluation and Reporting 35 event 2,000 55,125 413,438

3. In-situ Bioremediation Groundwater Monitoring and Sampling (3) 35 event 9,000 248,063

Design, Permitting, Installation and Development of New Wells 4 well 8,500 34,000

ORC Compound for 2 Treatments 2 Est. 110,000 220,000

Data Analyses, Evaluation & Reporting 2 event 25,000 50,000 552,063

Notes:(1) Present worth adjustments made for future costs on items labeled with Note (2). Present worth adjustments calculated based on annual discount rate of 3.4%.

(3) Semi-annual monitoring for years 1 through 5 followed by annual monitoring from years 6 through 30 for select wells.

Quantity Unit Rate ($)Present(1)

Worth Subtotal

($)

Present Worth

Total ($)Alternative

(2) Semi-annual monitoring for years 1 through 5 followed by annual monitoring from years 6 through 30.

of 1

Table 5-4A Screening of Remedial Alternatives for Soil


Alternative Number Description

Selection Criteria

Effectiveness Implementability Reasons for Selection Cost

1

No Action

Very limited land use, no reduction in toxicity, mobility, or volume.

No technology involved. Feasible, but, considerable institutional obstacles. Not desirable to regulatory agencies.

Required by NCP. Serves as a baseline reference for the other retained alternatives. $0

2

Install and maintain cap over contaminated soil; maintain deed restriction to prohibit activities that could damage or penetrate cap and to control onsite construction activities.

Limits land use, but minimizes exposure potential to contaminated soil. Minimal reduction in toxicity, mobility, or volume.

Technically feasible and readily implemented. Bears minimal institutional and administrative obstacles.

Contamination remains in soil. Minimizes direct contact with contaminated surface soil and prevents surface water infiltration. Commercial uses continue. $520,000

3

Remove and treat/recycle contaminated shallow soil by thermal desorption treatment at an offsite facility; backfill with clean soil to grade and compact; restore the Site.

Unrestricted land use in remediated areas. Complies with ARARs, and results in considerable reduction in toxicity, mobility, and volume of contamination.

Technically feasible, but difficult to implement considering existing structural improvements. Results in minimal institutional obstacles. Some potential community and administrative obstacles.

Contaminated soil at the Site will be removed. Complies with ARARs. Probably most acceptable to owners and regulatory agencies. Relatively high cost. Does not require any institutional control, if remedial goals are achieved. Residential uses possible.

$1,872,000

4

Remove contaminated surface soil and dispose of contaminated soil at a proper landfill; backfill with clean soil to grade and compact; restore the Site.

Unrestricted land use in remediated areas. Complies with ARARs; but results in no net reduction in toxicity, or volume.

Technically feasible, but difficult to implement considering existing structural improvements. Results in minimal institutional obstacles. Some potential community and administrative obstacles.

Contaminated soil at the Site will be removed. Complies with ARARs. Less preferred by agencies compared to offsite treatment alternative. High cost. Does not require any institutional control. Residential uses possible.

$1,759,500

(1) Retention of No Action alternative is required by the National Contingency Plan (NCP, 1990).

of 1

Table 5-4B Screening of Remedial Alternatives for Soil Gas



Selection Criteria


1

No Action

Limited land use, no reduction in toxicity, mobility, or volume.


Required by NCP. Serves as a baseline reference for the other retained alternatives. $0

2

Soil Gas Monitoring. Sample soil gas on a semi-annual basis; maintain deed restriction to prohibit construction of building on east side of property.

Limits land use, but minimizes exposure potential to contaminated soil gas. Minimal reduction in toxicity, mobility, or volume due to continued natural attenuation.

Technically feasible and readily implemented. Bears minimal institutional and administrative obstacles.

Contamination remains in soil gas. Provides verification that contaminated soil gas is not migrating to building foundation.

$347,288

3

Installation of vapor extraction wells between impacted area and building and within impacted area, and extract and treat potentially contaminated soil gas; sample soil gas on a semi-annual basis; maintain deed restriction to prohibit construction of building on east side of property.

Limits land use, but further minimizes exposure potential to contaminated soil gas compared to Alt. 2. Minimal reduction in toxicity, mobility, or volume due to continued natural attenuation and soil vapor extraction.

Technically feasible, but more difficult to implement considering existing structural improvements. Results in minimal institutional obstacles. Some potential community and administrative obstacles.

Vapor extraction will provide hydraulic barrier for potential soil gas migration toward building. Relatively high cost.

$1,042,569

(1) Retention of No Action alternative is required by the National Contingency Plan (NCP, 1990).

of 1

Table 5-4C Screening of Remedial Alternatives for Groundwater



Selection Criteria


1

No Action

No reduction in toxicity, mobility, or volume.


Required by NCP. Serves as a baseline reference for the other retained alternatives.

$0

2

Monitored Natural Attenuation. Monitor and sample groundwater on a semi annual basis.

Slow reduction in toxicity, mobility, or volume.

Technically feasible and readily implemented.

Technically viable alternative for low-level petroleum hydrocarbons. Readily implemented, complies with ARARs, and cost effective.

$413,438

3

In situ Bioremediation

Effective at reducing toxicity, mobility, or volume.

Technically feasible but may be difficult to implement due to low permeability sediments.

Technically viable alternative for petroleum hydrocarbons. Readily implemented, complies with ARARs. Also retained as contingency should MNA prove ineffective.

$552,063

(1)Retention of No Action alternative is required by the National Contingency Plan (NCP, 1990).

FIGURES

APPENDIX A

SCREENING-LEVEL VAPOR INTRUSION AND SOIL DATA HEALTH RISK EVALUATION REPORT

`

DRAFT

SCREENING-LEVEL VAPOR INTRUSION

AND SOIL HEALTH RISK EVALUATION

Former Watsonville-1 Manufactured Gas Plant Site

618 Main Street, Watsonville, California

February 26, 2010

Prepared for: Pacific Gas and Electric Company

3401 Crow Canyon Road San Ramon, California 94583

Prepared by:

IRIS ENVIRONMENTAL 1438 Webster Street, Suite 302

Oakland, California 94612 (510) 834-4747

Screening-level Vapor Intrusion February 26, 2010 and Soil Health Risk Evaluation DRAFT Former Watsonville-1 MGP Site

i IRIS ENVIRONMENTAL

TABLE OF CONTENTS

Table of Contents ............................................................................................................................. i 1.0 Introduction ......................................................................................................................... 1 2.0 Vapor Intrusion Health Risk Evaluation ............................................................................. 1

2.1 Soil Gas Characterization ............................................................................................... 1 2.2 Chemicals of Potential Concern...................................................................................... 2 2.3 Johnson and Ettinger Transport Modeling ...................................................................... 3

2.3.1 Source Characterization .......................................................................................... 4 2.3.2 Physicochemical Properties .................................................................................... 4 2.3.3 Lithology and Building Parameters ........................................................................ 5 2.3.4 Soil Properties ......................................................................................................... 5 2.3.5 Modeling Results .................................................................................................... 5

2.4 Screening-level Inhalation Risk Evaluation.................................................................... 6 2.4.1 Cancer Risk ............................................................................................................. 6 2.4.2 Noncancer Hazard ................................................................................................... 7

2.5 Results and Conclusions ................................................................................................. 9 2.5.1 Existing Commercial Building ............................................................................. 11 2.5.2 Future Residential Building .................................................................................. 11

3.0 Soil Data Evaluation ......................................................................................................... 12 3.1 Site Soil Data ................................................................................................................ 12 3.2 Risk-based Screening Levels ........................................................................................ 12 3.3 Soil Data Evaluation Results ........................................................................................ 13 3.4 Discussion of Soil Data Evaluation Results.................................................................. 14 3.5 Summary and Conclusions ........................................................................................... 15

4.0 References ......................................................................................................................... 15

Tables Table 1. Results of Soil Gas Investigations

Table 2. Johnson and Ettinger Model Input Data – Commercial Scenario

Table 3. Johnson and Ettinger Model Input Data – Residential Scenario

Table 4. Physicochemical Properties

Table 5. Attenuation Factors – Commercial Scenario

Table 6. Attenuation Factors – Residential Scenario

Table 7. Modeled Indoor Air Concentrations – Commercial Scenario

Table 8. Modeled Indoor Air Concentrations – Residential Scenario

Table 9. Cancer and Noncancer Toxicity Values

Table 10. Exposure Assumptions


ii IRIS ENVIRONMENTAL

Table 11. Cancer Risk – Commercial Scenario

Table 12. Cancer Risk – Residential Scenario

Table 13. Noncancer Hazard – Commercial Scenario

Table 14. Noncancer Hazard – Residential Scenario

Table 15. Comparison of Site Soil Data to Published Levels of Concern

Figures Figure 1. Site Plan and Soil Gas Sampling Locations

Figure 2. Modeled Soil Lithology and Building Geometry – Slab-on-grade Scenario

Figure 3. Modeled Soil Lithology and Building Geometry – Basement Scenario

Appendices

Appendix A Example Johnson and Ettinger Model Report

Appendix B Soil Sampling Locations and Results (TPG, 2009)


1 IRIS ENVIRONMENTAL

1.0 INTRODUCTION

This report summarizes the methodology and results of a screening-level vapor intrusion health risk evaluation and a screening-level soil evaluation for the portion of the Former Watsonville-1 Manufactured Gas Plant Site located at 618 Main Street in Watsonville, California. The 618 Main Street property (the “site”) is approximately 0.4 acres in size and is currently occupied by one commercial building, a Mexican restaurant (Jalisco). The site was previously part of a larger property which was occupied by the Watsonville-1 Manufactured Gas Plant. Previous investigations at the site have documented the presence of chemicals in site soil, groundwater, and/or soil gas, including: polycyclic aromatic hydrocarbons (PAHs); total petroleum hydrocarbons in the gasoline (TPH-g) and diesel (TPH-d) ranges; volatile organic compounds (VOCs) including benzene, toluene, ethylbenzene, and xylenes (BTEX); and metals (TPG, 2009).

Based on a review of the Additional Subsurface Investigation Report, Former Watsonville-1 Manufactured Gas Plant, 618 Main Street, Watsonville, California (TPG, 2009), the California Environmental Protection Agency (Cal/EPA) Department of Toxic Substances Control (DTSC) has requested that a screening-level risk evaluation be conducted using the soil gas results to address the possibility that volatile chemicals present in the subsurface may migrate upwards via diffusion through the vadose (unsaturated) soil zone, and be transported by advection through cracks, conduits, or seams in the building foundation into the indoor air space of the existing onsite commercial building (a transport phenomenon known as “vapor intrusion”). This screening-level vapor intrusion health risk evaluation is described in Section 2.0.

In addition to the screening-level vapor intrusion health risk evaluation, DTSC has requested that site soil data from several site investigations from 1986 to 2008 be compared to conservative screening levels. This evaluation is described in Section 3.0 and consists of comparing maximum soil concentration data against risk-based screening levels published by Cal/EPA and the United States Environmental Protection Agency (USEPA) and, for some chemicals, against background levels.

The purpose of the screening-level vapor intrusion and soil health risk evaluations is to support the remedy selection process, as described in the main text of the Removal Action Workplan (RAW). As mentioned in the RAW, a deed restriction was placed on the property in 2001, to limit the land use to commercial operations. The screening-level soil health risk evaluation presented here supports that the deed restriction is needed until the time at which further evaluations support that site conditions are safe and protective of future residential land use.

2.0 VAPOR INTRUSION HEALTH RISK EVALUATION

2.1 Soil Gas Characterization

The soil gas data used to model vapor intrusion are the results of the site soil gas investigations conducted in February 2008 and October 2009 by Terra Pacific Group, as presented in Table 1. Soil gas samples collected from locations near the restaurant building – SG-1, SG-1A, SG-2,



SG-2A, SG-3, SG-3A, and SG-8 – are used to evaluate a current commercial land use scenario, i.e., are used to evaluate potential vapor intrusion into the existing onsite commercial building. Soil gas samples collected from all locations are used to evaluate a hypothetical future residential scenario, i.e., are used to evaluate potential vapor intrusion into a future residence that may be constructed anywhere onsite. Soil gas samples were collected from 5 feet below ground surface (bgs) and 15 feet bgs, except at SG-1A where the deep sample was collected from 9 feet bgs. As explained further below, locations near the basement of the restaurant (SG-2A and SG-3A) are conservatively modeled as a basement scenario in evaluating the current commercial scenario.

2.2 Chemicals of Potential Concern

The chemicals of potential concern (COPCs) of this vapor intrusion evaluation are the 24 volatile chemicals detected in soil gas during either or both of the February 2008 or October 2009 soil gas investigations, by either Method 8260 or Method TO-15, as presented in Table 1. Included among these previously detected 24 volatile “chemicals” is total petroleum hydrocarbons in the gasoline range (TPH-g), which comprises a mixture of individual hydrocarbon compounds within the gasoline carbon range.

Based on DTSC guidance, the noncancer health effects of total petroleum hydrocarbon (TPH) mixtures are evaluated differently than all other COPCs (Cal/EPA, 2009b). (The cancer health effects associated with TPH are still evaluated on an individual-chemical basis, per USEPA and Cal/EPA guidance.) The DTSC TPH guidance provides noncancer toxicological values and physicochemical properties for four subgroups of TPH within the gasoline range, based on chemical structure and carbon number:

• C5 to C8 aliphatics;

• C9 to C18 aliphatics;

• C6 to C8 aromatics; and

• C9 to C16 aromatics.

DTSC still recommends evaluating the noncancer health effects of C6 to C8 aromatics on an individual chemical basis (Cal/EPA, 2009b). The noncancer health effects of the remaining three TPH-g subgroups are evaluated in accordance with the DTSC interim guidance; soil gas screening levels are developed for each of these three TPH-g subgroups based on toxicity data and physicochemical properties published in the interim guidance.

As recommended in the DTSC interim guidance (Cal/EPA, 2009b), it is conservatively assumed that the TPH-g mixture measured in site soil gas is comprised of 50 percent aliphatics and 50 percent aromatics. With respect to carbon number, it is assumed that the TPH-g measured in site soil gas is comprised of 75 percent short-chain hydrocarbons and 25 percent long-chain hydrocarbons within each of the aromatic and aliphatic groups, based upon fractionation data for fresh gasoline product published by Metcalf and Eddy (1993). The TPH-g measured in site soil gas is therefore assumed to be comprised of 37.5 percent C5 to C8 aliphatics; 37.5 percent C6 to C8 aromatics; 12.5 percent C9 to C18 aliphatics; and 12.5 percent C9 to C16 aromatics. Attenuation factors are modeled for each TPH-g subgroup, and then combined based on these



fractions to calculate an overall attenuation factor for TPH-g. Similarly, the noncancer toxicity values published by DTSC for each TPH-g subgroup are combined, using the same fractions, to calculate an overall noncancer toxicity value for TPH-g.

It should be noted here that TPH-g is a catch-all measurement that represents the summation of the concentrations of all detected hydrocarbon compounds in the gasoline range, i.e., from C5 to C12. It should not be assumed, however, that the concentrations of TPH-g measured in soil gas are necessarily associated with gasoline fuel, as there are many hydrocarbons within this range that would be included in the quantitation of TPH-g that are not gasoline constituents. The TPH noncancer toxicity values published by DTSC do assume that TPH-g is gasoline-related; e.g., the noncancer toxicity of the C5 to C8 aliphatic fraction is (by DTSC) conservatively based upon the most toxic gasoline constituent within that fraction, hexane. Furthermore, it is conservatively assumed here that the fractionation by carbon number of the TPH-g measured at the site is consistent with that of fresh gasoline product. Application of this noncancer toxicity value to evaluate site TPH-g measurements is therefore highly conservative, because the toxicity value assumes the TPH-g resembles fresh gasoline product, whereas the TPH-g measured at the site may not be related to gasoline at all, or may be related to highly weathered gasoline which would exhibit a different, and likely less toxic, speciation.

2.3 Johnson and Ettinger Transport Modeling

In this analysis, the vapor intrusion transport process is modeled to estimate concentrations of volatile chemicals that could potentially be present in the indoor air space of the existing onsite commercial building or a hypothetical future residential building, and a screening-level human health risk evaluation is performed to quantify the associated potential inhalation health risks to commercial workers or residents.

The transport of volatile chemicals from soil gas to indoor air is modeled using the USEPA-recommended Johnson and Ettinger model for soil gas (SG-SCREEN Version 2.0), as modified by the Cal/EPA DTSC Human and Ecological Risk Division (HERD) (Johnson and Ettinger, 1991; USEPA, 2004a; Cal/EPA, 2009a), and as modified by Iris Environmental to allow for the input of multiple chemicals and site-specific building parameters. As recommended by DTSC (Cal/EPA, 2005c), soil gas data, rather than soil or groundwater data, are used to evaluate the vapor intrusion pathway, because soil gas data represent a direct measurement of the volatile chemicals that could migrate into indoor air. The potential health risks associated with inhalation of volatile COPCs in the indoor air of the onsite building are estimated using standard Cal/EPA Office of Environmental Health Hazard Assessment (OEHHA) and DTSC risk-assessment methodology (Cal/EPA, 2005b; Cal/EPA, 2009a).

Inputs to the Johnson and Ettinger model include depth and concentration of soil gas contamination, physicochemical properties of the chemicals being transported, lithology and building parameters, and soil properties. The existing onsite commercial building has a partial basement that is approximately 15 feet by 25 feet and extends to a depth of approximately 10 feet bgs (305 centimeters [cm]) bgs (see Figure 1) (TPG, 2008b); the building is otherwise of slab-on-grade construction. Transport of volatile chemicals into the existing commercial building is modeled for both basement and slab-on-grade building geometries, to evaluate soil



gas data collected near the basement and away from the basement, respectively. The hypothetical future residential building is assumed to be of slab-on-grade construction. Model input data are documented in Tables 2 and 3 for the commercial and residential scenarios, respectively, and are discussed below in this section.

2.3.1 Source Characterization

To characterize worst-case impacts, vapor intrusion into commercial and residential buildings is modeled on an individual soil gas sample basis, i.e., the transport of COPCs from each boring location and sampling depth (5 feet bgs and 15 feet bgs) is evaluated separately.

The evaluation of vapor intrusion into the existing onsite commercial building considers the results of soil gas samples collected at locations SG-1, SG-1A, SG-2, SG-2A, SG-3, SG-3A, and SG-8, which are adjacent to this existing building (see site plan in Figure 1). As noted above, the existing onsite commercial building has a partial basement which extends, where present, to an estimated depth of 10 feet bgs; the shallow soil gas contamination measured at 5 feet bgs adjacent to the basement (at SG-2, AG-2A, SG-3 and SG-3A) is assumed to be present just below the basement slab for the purpose of modeling transport of COPCs from shallow soil gas into the existing commercial building (note the model requires that the depth to contamination be at least 1 cm below the bottom of the slab, thus the shallow soil gas contamination is assumed to be located at 306 cm for the basement scenario). Note that a soil gas sample could not be collected at 15 feet bgs from locations SG-1 and SG-1A, due to encountered perched groundwater.

The evaluation of potential vapor intrusion into hypothetical future onsite residential buildings considers the complete soil gas sample set as it is assumed that future residential development could occur anywhere onsite.

At some sampling locations, a second soil gas sample was collected for independent analysis by Method TO-15, to confirm the results of the primary analysis by Method 8260. At those locations with both an 8260 and TO-15 sample, a “composite” sample is created by taking the higher concentration (from either sample) of each chemical to represent soil gas conditions at that location. This process is documented in Table 1.

2.3.2 Physicochemical Properties

Physicochemical properties that are used by the Johnson and Ettinger model to simulate the transport of volatile chemicals through the subsurface include: diffusivity in water, diffusivity in air, Henry’s Law constant, molecular weight, and other properties. These data are used by the model to calculate the effective diffusivity of the volatile chemical through the vadose zone, which varies slightly from chemical-to-chemical. These input data are documented in Table 4.



2.3.3 Lithology and Building Parameters

The screening-level Johnson & Ettinger model for soil gas used in this analysis (SG-SCREEN Version 2.0) is a one-soil-layer model. Soil properties associated with this layer are discussed in Section 2.3.4.

To evaluate potential vapor intrusion into the existing onsite commercial building, two distinct building geometries are modeled: basement and slab-on-grade. Attenuation factors developed assuming the basement geometry are applied to the soil gas data collected near the basement, at locations SG-2, SG-2A, SG-3 and SG-3A. Attenuation factors developed assuming the slab-on-grade geometry are applied to the soil gas data collected away from the basement (but still near the building), at locations SG-1, SG-1A, and SG-8.

Existing Commercial Building

When modeling vapor intrusion transport into a building with a basement, the predicted attenuation factors and predicted concentrations of COPCs in indoor air are those associated with the basement space. Concentrations of COPCs in the indoor air of the aboveground portion of the building would likely be lower.

For both the basement and slab-on-grade building geometries, a default building area (Cal/EPA, 2009a) and default air exchange rate (Cal/EPA, 2005a) for a commercial building are assumed. Values of model inputs are documented in Table 2 for the commercial scenario.

The hypothetical future onsite residential building is assumed to have default slab-on-grade building dimensions (Cal/EPA, 2005a). The modeled residential building geometry is depicted in Figure 2. The assumed air exchange rate is the default for evaluating a residential exposure scenario (Cal/EPA, 2005a). Values of model inputs are documented in Table 3 for the residential scenario.

Hypothetical Future Residential Building

2.3.4 Soil Properties

Soil-property inputs to the screening-level Johnson & Ettinger model are total porosity, water-filled porosity, bulk density, and temperature. The assumed soil temperature of the soil layer is the USEPA-recommended default value for Watsonville, California (USEPA, 2004a). Conservative default values are assigned to the other soil properties (Cal/EPA, 2009a). These input data are documented in Tables 2 and 3, for the commercial and residential scenarios, respectively.

2.3.5 Modeling Results

The output parameter of the Johnson and Ettinger model is the attenuation factor (α). By definition, the attenuation factor is the ratio of the chemical concentration in indoor air (resulting from vapor intrusion) to the chemical concentration in soil gas beneath the building at the specified depth:



SG

IA

CC

α ≡ (1)

where:

α = attenuation factor (unitless);

CIA = concentration of chemical in indoor air (µg/m3); and

CSG = concentration of chemical in soil gas at specified depth (µg/m3).

An attenuation factor is calculated with the Johnson and Ettinger model for each chemical in soil gas, at 5 and 15 feet bgs for the slab-on-grade scenario and at 10 and 15 feet bgs for the basement scenario. These chemical- and depth-specific attenuation factors are summarized in Tables 5 and 6, for the commercial and residential scenarios, respectively. For modeling potential vapor intrusion into the existing onsite commercial building, the commercial-building-with-basement attenuation factors are applied to the soil gas data collected near the basement (at SG-2, SG-2A, SG-3 and SG-3A), and the commercial slab-on-grade building attenuation factors are applied to the soil gas data collected away from the basement (but still near the building) (at SG-1, SG-1A, and SG-8). For modeling potential vapor intrusion into hypothetical future onsite residential buildings, the residential slab-on-grade building attenuation factors are applied to all soil gas data collected at the site. Estimated indoor air concentrations calculated by Equation 1 are presented in Tables 7 and 8, for the commercial and residential scenarios, respectively. An example Johnson and Ettinger model report is presented in Appendix A.

2.4 Screening-level Inhalation Risk Evaluation

This section presents a screening-level health risk evaluation that considers a single exposure route: inhalation of volatile COPCs that could be present in indoor air of onsite buildings as a result of vapor intrusion from the subsurface. Two receptor populations are considered: current indoor commercial workers present in the existing onsite commercial building, and residents present in a hypothetical future onsite residential building. The incremental cancer risk and noncancer health hazard associated with inhalation of volatile COPCs that could be present in indoor air are estimated using standard OEHHA and DTSC inhalation risk assessment methodology (Cal/EPA, 2005b; Cal/EPA, 2009a), as described below.

2.4.1 Cancer Risk

The lifetime incremental cancer risk associated with inhalation of each volatile COPC that could be present in the indoor air of onsite buildings is estimated using standard OEHHA and DTSC inhalation risk assessment methodology (Cal/EPA, 2005b; Cal/EPA, 2009a):

cATEDEFCAURFRISK ×

××= (2)

where:

RISK = inhalation cancer risk (unitless);

URF = inhalation unit risk factor (per µg/m3);



CA = concentration of chemical in air (µg/m3);

EF = exposure frequency (days/year);

ED = exposure duration (years);

ATc = averaging time for carcinogenic effects (days).

The inhalation carcinogenic potency of each COPC is defined by its unit risk factor (URF). The unit risk factor represents the estimated probability of the receptor getting cancer as a result of a constant exposure to an ambient concentration of 1 microgram per cubic meter (µg/m3) of the chemical over a 70-year lifetime (USEPA, 1989). Consistent with Cal/EPA guidance (2005b), URF values are obtained from the OEHHA Toxicity Criteria Database (Cal/EPA, 2010). Toxicity values are presented in Table 9.

The chemical concentration in indoor air (CA) is that predicted using the Johnson and Ettinger model, as discussed above and presented in Tables 7 and 8. Values assigned to the exposure parameters – exposure frequency (EF), exposure duration (ED), and averaging time for carcinogenic effects (ATc) – are documented in Table 10. These values are consistent with standard Cal/EPA DTSC exposure assumptions (Cal/EPA, 2005d).

As a matter of policy, USEPA (1989) considers the potential cancer risks from exposure to multiple carcinogens to be additive, regardless of the carcinogens’ mechanisms of toxicity or sites (organs of the body) of action. Therefore, the chemical-specific cancer risks calculated by Equation 2 may be summed across all carcinogenic chemicals to produce an estimate of the cumulative (multi-chemical) inhalation cancer risk associated with each soil gas sample.

This estimated cancer risk may be compared to the “acceptable” cancer risk, as defined and endorsed by relevant state and federal agencies. The National Contingency Plan (NCP) is cited by USEPA (1989) as the basis for defining acceptable incremental risk levels. According to the NCP, lifetime incremental cancer risk levels posed by a site should be within the risk range of one in a million (1×10-6) to 100 in a million (1×10-4). Thus, USEPA and Cal/EPA agencies typically consider the 10-6 risk level to be an insignificant risk, and consider a calculated excess cancer risk between 1×10-6 and 1×10-4 to be within the acceptable risk range. The threshold risk level under California Proposition 65 is the logarithmic midpoint of the acceptable risk range: 10 in a million (1×10-5).

2.4.2 Noncancer Hazard

The noncancer health hazard associated with inhalation of each volatile COPC that could be present in the indoor air of onsite buildings is estimated using standard OEHHA and DTSC inhalation risk assessment methodology (Cal/EPA, 2005b; Cal/EPA, 2009a):

ncATEDEFCA

RfC1HQ ×

××= (3)

where:

HQ = inhalation noncancer hazard quotient (unitless);



RfC = inhalation reference concentration (µg/m3); and

ATnc = averaging time for noncarcinogenic effects (days).

The inhalation noncancer toxicity of a particular chemical is described by its inhalation chronic reference concentration (RfC). The chronic reference concentration is an estimate (with uncertainty spanning perhaps an order of magnitude) of the chemical concentration in air that a human population (including sensitive subgroups) may be continuously exposed to without an appreciable risk of deleterious effects. In accordance with current DTSC recommendation (Cal/EPA, 2009a), the chronic reference concentrations used in this health screening evaluation are taken from the following hierarchy of sources (in order):

1) The lower (more conservative) value from either

a) Cal/EPA OEHHA Toxicity Criteria Database (Cal/EPA, 2010) or

b) USEPA Integrated Risk Information System (IRIS) (USEPA, 2010); and

2) USEPA Regional Screening Levels for Chemical Contaminants at Superfund Sites (RSLs Table) (USEPA, 2009a).

The RfCs for TPH-g subgroups are obtained from DTSC interim guidance for evaluating the noncancer health effects of TPH mixtures (Cal/EPA, 2009b), as discussed in Section 2.2. These TPH-g subgroup-specific RfC values are combined to calculate a weighted-average RfC value for TPH-g mixture, based on the assumed fractionation of TPH-g measured at the site into the four TPH-g subgroups.

The chronic inhalation RfCs used in this evaluation are documented in Table 9.

The chemical concentration in indoor air (CA) is that predicted using the Johnson and Ettinger model, as discussed above. Values assigned to the exposure parameters are documented in Table 10; these values are consistent with standard Cal/EPA OEHHA exposure assumptions for indoor commercial workers and residents (Cal/EPA, 2005d).

The chemical-specific noncancer hazard quotients calculated by Equation 3 may be summed across all chemicals to produce an estimate of the cumulative (multi-chemical) inhalation “hazard index” associated with each soil gas sample. It should be noted here that the summation of hazard quotients across chemicals, independent of the target organ which is affected by each chemical, is conservative, as chemicals that impact different target organs (e.g., liver, kidney) are not truly additive in their potential to cause the adverse impact. USEPA risk assessment guidance (USEPA, 1989) states, “application of the hazard index equation to a number of compounds that are not expected to induce the same type of effects or that do not act by the same mechanism could overestimate the potential for effects, although such an approach is appropriate at a screening level.”

This estimated noncancer HI is compared to the threshold value 1.0. An HI of less than 1.0 indicates that the exposure is not likely to result in adverse noncancer health effects (USEPA, 1989).



2.5 Results and Conclusions

The estimated incremental cancer risk associated with inhalation of volatile chemicals that could be present in the indoor air of the existing onsite commercial building or a future hypothetical residential building as a result of vapor intrusion are documented in Tables 11 and 12 for the commercial and residential scenarios, respectively. The estimated incremental noncancer hazard associated with inhalation of volatile chemicals that could be present in the indoor air of the existing onsite commercial building or a future hypothetical residential building as a result of vapor intrusion are documented in Tables 13 and 14 for the commercial and residential scenarios, respectively. As described above, the cumulative cancer risk and noncancer hazard is calculated for each soil gas sample, as summarized below.



Results of Screening-level Vapor Intrusion Health Risk Evaluation

Sample ID Risk Hazard Risk Hazard

SG-1-5 3.2E-08 5.4E-04 1.1E-07 1.5E-03

SG-1A-5 4.6E-07 1.7E-02 1.5E-06 4.8E-02

SG-1A-9 3.6E-08 3.0E-03 1.2E-07 8.5E-03

SG-2-5 1.9E-07 1.6E-03 3.5E-07 2.2E-03

SG-2-15 2.9E-08 5.1E-04 4.2E-08 6.2E-04

SG-2A-5 8.7E-08 1.4E-03 1.2E-07 1.7E-03

SG-2A-15 3.3E-08 5.5E-04 4.9E-08 6.6E-04

SG-3-5 7.6E-08 1.3E-03 1.1E-07 1.6E-03

SG-3-15 2.9E-08 5.5E-04 4.2E-08 6.7E-04

SG-3A-5 8.7E-08 1.9E-02 1.2E-07 3.2E-02

SG-3A-15 3.3E-08 5.5E-04 4.9E-08 6.6E-04

SG-4-5 NA NA 6.8E-06 7.7E-02

SG-4-15 NA NA 2.0E-04 1.6E+00

SG-4A-5 NA NA 6.9E-07 7.9E-02

SG-4A-15 NA NA 5.5E-04 3.2E+01

SG-5-5 NA NA 1.1E-07 1.6E-03

SG-5-15 NA NA 1.1E-06 5.9E-03

SG-5A-5 NA NA 4.3E-07 2.1E-02

SG-5A-15 NA NA 7.0E-07 3.4E-02

SG-6-5 NA NA 7.7E-06 9.1E-02

SG-6-15 NA NA 9.2E-05 4.5E-01

SG-6A-5 NA NA 8.1E-07 1.2E-01

SG-6A-15 NA NA 1.1E-04 4.8E+00

SG-7-5 NA NA 1.8E-06 1.5E-01

SG-7-15 NA NA 5.7E-06 2.9E-02

SG-8-5 3.6E-08 6.1E-04 1.2E-07 1.7E-03

SG-8-15 1.4E-08 2.4E-04 4.9E-08 6.6E-04

Maximum (Worst-case Sample) 4.6E-07 1.9E-02 5.5E-04 3.2E+01

NA = Sample not evaluated; sample not located near existing commercial building

Current Exisiting Commercial Building

Future Hypothetical Residential Building



2.5.1 Existing Commercial Building

The worst-case estimated cancer risk to onsite commercial workers, associated with inhalation of volatile COPCs present in indoor air as a result of vapor intrusion, is 4.6×10-7. This result is below the threshold of 1.0×10-6. The worst-case estimated noncancer hazard index is 1.9×10-2, which is two orders of magnitude below the threshold value of 1.0. Thus, it may be concluded from this evaluation that levels of VOCs in soil gas around the existing commercial building may be considered safe and acceptable for the current commercial use of the site.

Of note, the estimated cancer risk and hazard to current commercial workers associated with transport from shallow (5 feet bgs) soil gas are consistently higher than those associated with transport from deep soil gas (15 feet bgs), at all locations near the existing building. These results suggest that there is no chemical source present in this area of the site that is currently impacting soil gas conditions.

2.5.2 Future Residential Building

The worst-case estimated cancer risk to future hypothetical residents, associated with inhalation of volatile COPCs present in indoor air as a result of vapor intrusion, is 5.5×10-4, of which 60 percent is attributable to naphthalene and 22 percent is attributable to benzene. This future hypothetical result is slightly above the 1×10-6 to 1×10-4 risk management range. The future hypothetical worst-case estimated noncancer hazard index is 32, which is above the threshold level of 1.0. Both the worst-case cancer risk and worst-case noncancer hazard index are associated with the soil gas sample collected at location SG-4A at a depth of 15 feet bgs. There is considerable uncertainty associated with estimating vapor intrusion risk associated with future hypothetic buildings due to the potential changes in soil parameters caused by building construction activities.

Of note, the worst-case estimated cancer risk and noncancer hazard index associated with transport from shallow (5 feet bgs) soil gas are significantly lower than those associated with transport from deep soil gas (15 feet bgs). Typically, this may indicate that steady-state conditions have not been reached, and/or that diffusive transport of COPCs is influenced by site geology, which could be acting to retard the transport of deeper soil gas contaminants in a way unaccounted for by the Johnson and Ettinger model. Thus, the soil gas data suggest that diffusive transport of COPCs from 15 feet bgs to 5 feet bgs is not occurring to the extent predicted by the model, likely because of the use of very conservative default soil properties. The estimated cancer risk and noncancer hazard index associated with transport from shallow soil gas may be more representative of potential exposures to hypothetical future onsite residents.

Considering only transport from shallow soil gas, the worst-case estimated cancer risk is 7.6×10-6, which is within the 1×10-6 to 1×10-4 risk management range. Considering only transport from shallow soil gas, the worst-case estimated noncancer hazard index is 0.15, which is below the threshold level of 1.0.



3.0 SOIL DATA EVALUATION

3.1 Site Soil Data

Soil sampling has been conducted at the site between 1986 and 2008. Chemicals sampled-for in site soil include:

• 17 polycyclic aromatic hydrocarbons (PAHs), eight of which are carcinogenic;

• 18 metals, consisting of the 17 Title 22 metals plus hexavalent chromium;

• total petroleum hydrocarbons (TPH) in the gasoline, diesel, motor oil, and recoverable ranges;

• benzene, toluene, ethylbenzene, xylene (BTEX), and methyl tert-butyl ether MTBE); and

• ammonia, cyanide, sulfide, and total phenols.

Presented in Table 15 is a summary of site soil data including, for each chemical, the frequency of detection, average concentration, and maximum concentration of the combined soil dataset from the 1986 to 2008 site investigations. Nondetect results are assumed equal to one-half the laboratory reporting limit for the purpose of calculating these average concentrations.

Carcinogenic PAHs other than naphthalene are converted to benzo(a)pyrene equivalents for evaluation against a risk-based screening level for benzo(a)pyrene. On an individual soil sample basis, the reported concentration of each carcinogenic PAH (other than naphthalene) is converted to an equivalent benzo(a)pyrene concentration by multiplying the reported PAH concentration by the toxicity equivalent factor (TEF) for that carcinogenic PAH. The TEF values used in this calculation are those published by OEHHA (Cal/EPA, 1994b). Nondetect results are assumed equal to one-half the laboratory reporting limit for the purpose of this calculation. The calculated benzo(a)pyrene equivalents are then summed across the seven carcinogenic PAHs to yield the total benzo(a)pyrene equivalent concentration for the soil sample. Shown in Table 15 are the average and maximum benzo(a)pyrene equivalent concentrations of 149 soil samples analyzed for PAHs.

3.2 Risk-based Screening Levels

Site soil data are compared to published human health risk-based screening levels from the following hierarchy of sources (in order of preference, except where noted):

1) Cal/EPA OEHHA California Human Health Screening Levels (CHHSLs) for soil (Cal/EPA, 2005b);

2) USEPA Regional Screening Levels (RSLs) for soil (USEPA, 2008); and

3) San Francisco Bay Regional Water Quality Control Board (RWQCB) Environmental Screening Levels (ESLs) for soil considering direct exposure concerns (Cal/EPA, 2008)

The three types of soil screening levels used here – CHHSLs, RSLs, and ESLs – are based on the same three direct exposure routes: dermal contact with soil, ingestion of soil, and inhalation of dust or vapors in the ambient air. Vapor intrusion into overlying buildings is not incorporated



into these soil screening levels, nor are non-human health concerns such as leaching to groundwater. All screening levels are based on a target cancer risk of 1×10-6 and target noncancer hazard index of 1. Risk-based soil screening levels for residential and commercial/industrial exposure scenarios are presented in Table 15. Exceptions to the hierarchy presented above are documented in the Table 15 footnotes.

Additionally, as risk-based screening levels for benzo(a)pyrene are below typical background concentrations, Table 15 also presents a comparison of the benzo(a)pyrene equivalent concentrations detected in the soil to the background-based screening concentration for B(a)P equivalents that is presented in the Northern California background CPAH dataset (ENVIRON et al., 2002). As presented in the Northern California background study, the 95 percentile of the Northern California background dataset is 0.90 mg/kg. This is the initial screening value that is presented in Table 15, and used as an initial screen to assess whether concentrations of benzo(a)pyrene equivalents are present at levels greater than background concentrations.

A local arsenic background level of 10 mg/kg was recommended as an initial cleanup goal for the nearby Watsonville-2 former MGP site (TPG, 2008a). This background level is based on a combination of 16 local background samples collected from around the Watsonville-2 former MGP site, as well as a set of post-remediation soil samples collected from the Vista Montana (VM) Development, located within 2 miles of the site (incorporated and evaluated specifically at the request of the City of Watsonville and the Santa Cruz County Environmental Health Services Agency during the development of the Watsonville-2 Draft Remedial Action Plan). As is common with arsenic, the local background level of arsenic significantly exceeds the commercial risk-based screening level of 0.24 mg/kg.

3.3 Soil Data Evaluation Results

A comparison of site soil data to risk-based screening levels for residential and commercial/industrial exposure scenarios is presented in Table 15. Shown for each chemical are the frequency of exceedance of the residential screening level and the frequency of exceedance of the commercial/industrial screening level. For the purposes of this comparison, nondetect results are assumed equal to one-half the associated laboratory reporting limit (i.e., a nondetect result is counted as an exceedance if one-half the reporting limit is greater than the screening level). As discussed above, Table 15 also includes a comparison of benzo(a)pyrene equivalents and arsenic to their respective background concentrations.

The following table presents a summary of those chemicals that exceed their respective residential or commercial screening levels in at least one site soil sample:



Summary of Comparison of Soil Data to Screening Levels

Background Residential Commercial

Arsenic 90 2 90 90

Benzene 102 – 6* 2*

Benzo(a)pyrene equivalents 149 29 76 55

Chromium (hexavalent) 61 – 1 0

Ethylbenzene 102 – 2 0

Lead 58 – 1 0

Naphthalene 149 – 6 6

Total phenols 22 – 3 0

TPH-d 111 – 14 4

TPH-g 111 – 4 3

TPH-mo 84 – 7 0

* All samples in exceedance of the residential and commercial screening levels are nondetect results included in the analysis as one-half the reporting limit.

ChemicalTotal Number of

Soil Samples

Number of Soil Samples in Exceedance of Screening Level

3.4 Discussion of Soil Data Evaluation Results

As the current site usage is commercial, and will continue to be commercial in the future, the results for the commercial scenario soil data evaluation were analyzed in greater depth to support the remedial decision making at the site.

The background benzo(a)pyrene equivalent concentration of 0.90 mg/kg is exceeded in 29 of 149 (19 percent) samples. The background arsenic concentration of 10 mg/kg is exceeded in only two of 90 (2.2 percent) samples. The exceedances of the arsenic background level are a detection of 28 mg/kg from a soil sample collected in 1986 and a detection of 10.3 mg/kg from a soil sample collected in 1991. As indicated in Table 15, as the risk-based screening concentrations for both residential and commercial populations for arsenic and benzo(a)pyrene equivalents are below background concentrations, the relevant point of comparison for these compounds is the background concentration.

Although the tables indicate that TPH in the gasoline, diesel, and motor oil range was detected in numerous samples at concentrations that exceed either residential or residential and commercial screening concentrations, we note that the screening levels for all ranges of TPH are conservative. Specifically, TPH is a complex mixture of hundreds of different hydrocarbons. The development of soil screening levels for TPH requires assumptions of the carbon chain



ranges and structures present. The TPH ESLs developed by the RWQCB adopted the conservative assumptions made by the Massachusetts Department of Environmental Protection (Cal/EPA, 2008). In particular, for both the TPH-g and TPH-d ESLs, it is assumed that all of the TPH is in the relatively mobile C11-C22 aromatic range. In actuality, a fraction of the TPH is likely to be in less mobile forms which may be either heavier or aliphatic. Additionally, the toxicity values assumed for the C11-C22 aromatic range are based on those of pyrene and are more conservative that the toxicity values recommended by the TPH Working Group (TPHWG, 1998).

The depth of the soil sample is not considered in the comparison of site soil sample results to risk-based screening levels. In practice, soil samples at depths greater than 10 feet are typically not compared to risk-based screening levels which assume direct contact with the soil. All naphthalene soil samples in exceedance of the residential or commercial screening levels are from depths greater than 12 feet. All TPH-g samples in exceedance of the residential or commercial screening levels are from depths greater than 13 feet. All TPH-d samples in exceedance of the commercial screening level are from depths greater than 13 feet. All benzene samples in exceedance of the residential or commercial screening levels are from depths greater than 12 feet and are nondetect results included in the analysis at one-half the reporting limit.

3.5 Summary and Conclusions

Considering the factors described above, the primary constituents in soil that exceed applicable direct-contact commercial screening criteria (or background concentrations, where background concentrations are known to be greater than risk-based screening criteria) are the CPAHs. Any proposed remedy that effectively precludes the potential for direct contact, such as a cover or cap of the impacted soils, will protect current commercial workers from potential adverse health effects that could result from these direct exposures. In the event that the deed restriction were ever to be removed from the site, and residential development considered, additional risk-based evaluations of the soil constituents would be warranted.

4.0 REFERENCES

California Environmental Protection Agency (Cal/EPA). 1994a. Preliminary Endangerment Assessment Manual. Department of Toxic Substances Control (DTSC). January. Second printing June 1999.

Cal/EPA. 1994b. Memorandum, to Cal/EPA Departments, Boards, and Offices from Standards and Criteria Work Group, Office of Environmental Health Hazard Assessment (OEHHA). Subject: California Cancer Potency Factors. November 1.

Cal/EPA. 2003. 240 Locust Street Property: Results of Soil Sampling at 240 Locust Street. Fact Sheet from the Department of Toxic Substances Control. April.

Cal/EPA. 2004. Air Toxics Hot Spots Program Risk Assessment Guidelines Part II: Technical Support Document for Describing Available Cancer Potency Factors. Office of Environmental Health Hazard Assessment (OEHHA). Air Toxicology and Epidemiology Section. January.



Cal/EPA. 2005a. SG-SCREEN. Johnson and Ettinger screening-level soil gas model contained in Excel spreadsheet “HERD_Soil_Gas_Screening_Model_2005.xls”. Department of Toxic Substances Control (DTSC). Human and Ecological Risk Division (HERD). January 21.

Cal/EPA. 2005b. Human-Exposure-Based Screening Numbers Developed to Aid Estimation of Cleanup Costs for Contaminated Soil. Office of Environmental Health Hazard Assessment (OEHHA). Integrated Risk Assessment Section. January.

Cal/EPA. 2005c. Guidance for the Evaluation and Mitigation of Subsurface Vapor Intrusion to Indoor Air. Department of Toxic Substances Control. Interim Final. February 2.

Cal/EPA. 2005d. Recommended DTSC Default Exposure Factors for Use in Risk Assessment at California Military Facilities. Human Health Risk Assessment (HHRA) Note Number: 1. Department of Toxic Substances Control (DTSC). Human and Ecological Risk Division (HERD). October 27.

Cal/EPA. 2008. Screening for Environmental Concerns at Sites with Contaminated Soil and Groundwater. California Regional Water Quality Control Board (RWQCB), San Francisco Bay Region. Interim Final. May.

Cal/EPA. 2009a. SG-SCREEN. Johnson and Ettinger screening-level soil gas model contained in Excel spreadsheet “HERD_Soil_Gas_Screening_Model_2009_rev.xls”. Department of Toxic Substances Control (DTSC). Human and Ecological Risk Division (HERD). February 4.

Cal/EPA. 2009b. Interim Guidance Evaluating Human Health Risks from Total Petroleum Hydrocarbons (TPH). Department of Toxic Substances Control (DTSC). Human and Ecological Risk Division (HERD). June 16.

Cal/EPA. 2010. Toxicity Criteria Database. Office of Environmental Health Hazard Assessment (OEHHA). URL: http://www.oehha.org/risk/ChemicalDB/index.asp. Accessed February.

ENVIRON Corporation, Iris Environmental, and ENV America (ENVIRON et al.). 2002. Draft Background Levels of Polycyclic Aromatic Hydrocarbons in Northern California Surface Soil. May 31.

Iris Environmental. 2009. Screening Levels for Chemicals in Soil Gas, Sub-slab Soil Gas, and Indoor Air. Watsonville-1 Former Manufactured Gas Plant Site. October 23.

Johnson, P.C. and R.A. Ettinger. 1991. Heuristic Model for Predicting the Intrusion Rate of Contaminant Vapors into Buildings. Environ. Sci. Technol. 25, 1445-1452.

Metcalf and Eddy, Inc. 1993. Chemical and Physical Characteristics of Crude Oil, Gasoline, and Diesel Fuel: a Comparative Study. September 17.



Terra Pacific Group Incorporated (TPG). 2007. Removal Action Plan, Former Watsonville-1 Manufactured Gas Plant Site, 618 Main Street, Watsonville, California. April 24.

TPG. 2008a. Draft Remedial Action Plan Equivalent Document Watsonville-2 Former Manufactured Gas Plant Site. June 10.

TPG. 2008b. Personal communication between Max Reyhani of TGP and Robert Balas of Iris Environmental, regarding location and dimensions of basement beneath onsite commercial building. September 5.

TPG. 2009. Additional Subsurface Investigation Report, Former Watsonville-1 Manufactured Gas Plant Site, 618 Main Street, Watsonville, California. July 27.

Total Petroleum Hydrocarbon Working Group (TPHCWG). 1998. Analysis of Petroleum Hydrocarbons in Environmental Media. Ed.Wade Weisman. Amherst Scientific Publishers, Amherst, Massachusetts. ISBN 1-884-940-14-5.

United States Environmental Protection Agency (USEPA). 1989. Risk Assessment Guidance for Superfund Volume I: Human Health Evaluation Manual (Part A). Interim Final. Office of Emergency and Remedial Response. December.

USEPA. 1997. Health Effects Assessment Summary Tables (HEAST) FY 1997 Update. Office of Solid Waste and Emergency Response. EPA 540-R-97-036. July.

USEPA. 2002. Supplemental Guidance for Developing Soil Screening Levels for Superfund Sites. Office of Solid Waste and Emergency Response (OSWER). December.

USEPA. 2004a. User’s Guide for Evaluating Subsurface Vapor Intrusion into Buildings. Office of Emergency and Remedial Response. February 22.

USEPA. 2004b. Region 9 PRG Table. October. URL: http://epa.gov/region9/waste/sfund/prg/files/04prgtable.pdf

USEPA. 2008. Regional Screening Levels for Chemical Contaminants at Superfund Sites July 7, 2008. July 7.

USEPA. 2009. Regional Screening Levels for Chemical Contaminants at Superfund Sites. December.

USEPA. 2010. Integrated Risk Information System (IRIS). URL: http://www.epa.gov/iriswebp/iris/. Accessed February.

Screening-level Vapor Intrusion and Soil Data Health Risk EvaluationFormer Watsonville-1 MGP Site

February 26, 2010DRAFT

Table 1. Results of Soil Gas Investigations

Sample ID► SG-1-5 SG-1A-9 SG-2-15 SG-2A-5 SG-2A-15 SG-3-5 SG-3-15 SG-3A-5 SG-3A-15 SG-4-15 SG-4A-5 SG-5-5 SG-5-15 SG-5A-5 SG-5A-15 SG-6-5 SG-6-15 SG-6A-15 SG-7-5 SG-7-15 SG-8-5 SG-8-15 SG-9-5 SG-9-15 SG-10-5 SG-10-15

Sample Date► 02/13/08 10/12/09 10/12/09 10/12/09 02/13/08 02/13/08 02/13/08 10/12/09 10/12/09 02/13/08 02/13/08 10/12/09 10/12/09 02/12/08 02/12/08 02/12/08 10/12/09 10/12/09 10/12/09 02/13/08 02/12/08 10/12/09 10/12/09 02/12/08 02/12/08 10/12/09 10/12/09 10/12/09 02/12/08 02/12/08 10/12/09 10/12/09 10/12/09 10/12/09 10/12/09 10/12/09

Sample Method► 8260B 8260B TO-15 Combined 8260B 8260B TO-15 Combined 8260B 8260B 8260B 8260B 8260B 8260B 8260B 8260B TO-15 Combined 8260B 8260B 8260B TO-15 Combined 8260B 8260B 8260B 8260B 8260B 8260B 8260B TO-15 Combined 8260B 8260B 8260B 8260B 8260B 8260B 8260B 8260B 8260B

Chemical (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3)

TPH-Gasoline NS 6,170 8,500 8,500 1,490 NS NS NS NS < 8 < 8 NS NS 6,320 < 8 NS NS NS NS 15,400 6,170,000 6,200,000 6,200,000 NS NS 955 17,500 NS NS 6,650 19,000 19,000 946,000 NS NS < 8 < 8 180 6,200 1,260 4,030

Acetone NS NS 36 36 NS NS 32 32 NS NS NS NS NS NS NS NS 26 26 NS NS NS < 12000 < 12000 NS NS NS NS NS NS NS < 28 < 28 NS NS NS NS NS NS NS NS NS

Benzene < 7 < 8 < 9.6 < 8 < 8 < 7 30 30 < 7 < 8 < 8 < 7 < 7 < 8 < 8 571 9 571 41,500 < 8 26,800 20,000 26,800 < 7 214 < 8 109 608 19,100 < 8 16 16 3,540 51 1,190 < 8 < 8 < 8 < 8 50 < 20

Bromodichloromethane < 7 30 < 13 30 < 8 < 7 < 2 < 2 < 7 < 8 < 8 < 7 < 7 < 8 < 8 < 18 < 4 < 4 < 70 < 8 < 80 < 6800 < 80 < 7 < 18 < 8 < 8 < 18 < 18 < 8 < 16 < 8 < 20 < 18 < 18 < 8 < 8 < 8 < 8 < 8 < 20

2-Butanone (methyl ethyl ketone) NS NS < 30 < 30 NS NS 6 6 NS NS NS NS NS NS NS NS < 5.8 < 5.8 NS NS NS < 15000 < 15000 NS NS NS NS NS NS NS < 34 < 34 NS NS NS NS NS NS NS NS NS

n-Butylbenzene < 7 59 NS 59 < 8 < 7 NS < 7 < 7 < 8 < 8 < 7 < 7 < 8 < 8 < 18 NS < 18 < 70 60 < 80 NS < 80 < 7 < 18 57 < 8 < 18 < 18 76 NS 76 < 20 < 18 < 18 < 8 < 8 < 8 < 8 60 < 20

sec-Butylbenzene < 7 140 NS 140 < 8 < 7 NS < 7 < 7 < 8 < 8 < 7 < 7 < 8 < 8 < 18 NS < 18 < 70 145 < 80 NS < 80 < 7 < 18 < 8 < 8 < 18 < 18 301 NS 301 < 20 < 18 < 18 < 8 < 8 73 < 8 120 < 20

tert-Butylbenzene < 7 < 8 NS < 8 < 8 < 7 NS < 7 < 7 < 8 < 8 < 7 < 7 < 8 < 8 < 18 NS < 18 < 70 < 8 5,660 NS 5,660 < 7 < 18 102 105 < 18 < 18 < 8 NS < 8 995 < 18 < 18 < 8 < 8 < 8 < 8 < 8 < 20

Carbon disulfide NS NS < 31 < 31 NS NS 19 19 NS NS NS NS NS NS NS NS 8 8 NS NS NS < 16000 < 16000 NS NS NS NS NS NS NS < 36 < 36 NS NS NS NS NS NS NS NS NS

Chloroform < 7 384 560 560 < 8 < 7 < 1.5 < 1.5 < 7 < 8 < 8 < 7 < 7 < 8 < 8 < 18 < 3 < 3 < 70 < 8 < 80 < 4900 < 80 < 7 < 18 142 9 < 18 < 18 < 8 < 11 < 8 < 20 < 18 < 18 < 8 < 8 < 8 < 8 < 8 < 20

Cumene < 7 25 NS 25 < 8 < 7 NS < 7 < 7 < 8 < 8 < 7 < 7 < 8 < 8 < 18 NS < 18 1,650 30 25,800 NS 25,800 < 7 < 18 21 640 < 18 441 95 NS 95 9,870 < 18 < 18 < 8 < 8 < 8 < 8 24 < 20

Cymene < 7 43 NS 43 < 8 < 7 NS < 7 < 7 < 8 < 8 < 7 < 7 < 8 < 8 < 18 NS < 18 < 70 78 < 80 NS < 80 < 7 < 18 44 < 8 < 18 < 18 57 NS 57 < 20 < 18 < 18 < 8 < 8 48 < 8 90 < 20

Dichlorodifluoromethane (Freon 12) < 7 < 8 < 15 < 8 < 8 < 7 4 4 < 7 < 8 < 8 < 7 < 7 < 8 < 8 < 18 < 3 < 3 < 70 < 8 < 80 < 7500 < 80 < 7 < 18 < 8 < 8 < 18 < 18 < 8 < 17 < 8 < 20 < 18 < 18 < 8 < 8 < 8 < 8 < 8 < 20

Ethylbenzene < 7 18 < 8.7 18 < 8 < 7 4 4 < 7 < 8 < 8 < 7 < 7 < 8 < 8 525 15 525 26,500 671 283,000 180,000 283,000 < 7 < 18 < 8 124 940 10,400 649 82 649 43,500 1,260 358 < 8 < 8 < 8 < 8 201 < 20

4-Ethyltoluene NS NS < 9.8 < 9.8 NS NS 4 4 NS NS NS NS NS NS NS NS 46 46 NS NS NS 140,000 140,000 NS NS NS NS NS NS NS 88 88 NS NS NS NS NS NS NS NS NS

Methylene chloride < 7 < 8 11 11 < 8 < 7 2 2 < 7 < 8 < 8 < 7 < 7 < 8 < 8 < 18 < 2 < 2 < 70 < 8 < 80 < 3500 < 80 < 7 < 18 < 8 < 8 < 18 < 18 < 8 10 10 < 20 < 18 < 18 < 8 < 8 < 8 < 8 < 8 < 20Naphthalene < 7 < 8 < 31 < 8 < 8 < 7 < 2.6 < 2.6 < 7 < 8 < 8 < 7 < 7 < 8 < 8 < 18 < 5.2 < 5.2 < 70 < 8 85,800 < 16000 85,800 < 7 < 18 < 8 35 < 18 < 18 < 8 < 36 < 8 19,700 < 18 < 18 < 8 < 8 < 8 < 8 < 8 < 20n-Propylbenzene < 7 < 8 NS < 8 < 8 < 7 NS < 7 < 7 < 8 < 8 < 7 < 7 < 8 < 8 < 18 NS < 18 < 70 < 8 < 80 NS < 80 < 7 < 18 < 8 < 8 < 18 < 18 21 NS 21 < 20 < 18 < 18 < 8 < 8 < 8 < 8 < 8 < 20Styrene < 7 < 8 < 8.5 < 8 < 8 < 7 0.0035 JA 0.0035 JA < 7 < 8 < 8 < 7 < 7 < 8 < 8 < 18 0.03 JA 0.03 JA < 70 < 8 < 80 63,000 63,000 < 7 < 18 < 8 < 8 < 18 < 18 < 8 < 9.9 < 8 < 20 < 18 < 18 < 8 < 8 < 8 < 8 < 8 < 20Toluene 13 < 8 13 13 403 15 41 41 37 < 8 < 8 42 83 3,120 < 8 9,450 96 9,450 445,000 295 1,320,000 810,000 1,320,000 59 1,560 122 211 5,970 99,300 141 52 141 70,000 2,010 6,970 < 8 < 8 < 8 < 8 129 < 20Trichlorofluoromethane (Freon 11) < 7 < 8 < 11 < 8 < 8 < 7 3 3 < 7 < 8 < 8 < 7 < 7 < 8 < 8 < 18 < 4.4 < 4.4 < 70 < 8 < 80 < 5700 < 80 < 7 < 18 < 8 < 8 < 18 < 18 < 8 < 13 < 8 < 20 < 18 < 18 < 8 < 8 < 8 < 8 < 8 < 201,2,4-Trimethylbenzene < 7 142 < 15 142 < 8 < 7 5 5 < 7 < 8 < 8 < 7 < 7 < 8 < 8 < 18 33 33 1,130 147 114,000 110,000 114,000 < 7 < 18 119 46 < 18 < 18 342 54 342 11,100 < 18 < 18 < 8 < 8 58 < 8 113 < 201,3,5-Trimethylbenzene < 7 21 < 15 21 < 8 < 7 < 2.4 < 2.4 < 7 < 8 < 8 < 7 < 7 < 8 < 8 < 18 25 25 1,240 67 157,000 70,000 157,000 < 7 < 18 27 52 < 18 < 18 188 93 188 29,600 < 18 < 18 < 8 < 8 < 8 < 8 30 < 20Xylenes < 7 202 27 202 85 < 7 24 24 < 7 < 8 < 8 < 7 < 7 < 8 < 8 3,160 430 3,160 130,000 1,050 2,170,000 1,800,000 2,170,000 < 7 < 18 321 527 6,000 24,700 1,140 400 1,140 258,000 16,000 1,100 < 8 < 8 < 7 < 7 291 205

Notes:

(1) Concentration units are micrograms per cubic meter (µg/m3). Where a chemical was not detected above the laboratory reporting limit, a less-than sign (<) and the reporting limit are shown.

(2) "NS" indicates chemical was not analyzed for in the sample using the associated sample method.

(3) "JA" indicates estimated value because of interference by non-target compounds.

SG-6A-5SG-1A-5 SG-2-5 SG-4-5 SG-4A-15

Page 1 of 1 IRIS ENVIRONMENTAL



Table 2. Johnson and Ettinger Model Input Data – Commercial Scenario

Parameter Symbol Slab-on-grade Basement Units Reference

Building PropertiesDepth below grade to bottom of enclosed space floor LF 15 305 cm DTSC/HERD default (Cal/EPA, 2005c; 2009a)

Building height H 244 366 cm USEPA default (USEPA, 2004a)

Building area A 1.0E+06 1.0E+06 cm2 DTSC/HERD default (Cal/EPA, 2005c; 2009a)

Area of enclosed space below grade Ab 1.0E+06 1.8E+06 cm2 DTSC/HERD default (Cal/EPA, 2009a)

Building air exchange rate AXRb 1.0 1.0 hr-1 DTSC default (Cal/EPA, 2005c)

Vapor flow rate into building Qsoil 5 5 L/min DTSC/HERD default (Cal/EPA, 2005c; 2009a)

Soil Properties

Average soil temperature Ts 17 17 oC Site-specific (Cal/EPA, 2005c)

Dry bulk density ρb 1.50 1.50 g/cm3 DTSC/HERD default (Cal/EPA, 2005c; 2009a)

Total porosity η 0.430 0.430 cm3/cm3 DTSC/HERD default (Cal/EPA, 2009a)

Water-filled porosity θw 0.150 0.150 cm3/cm3 DTSC/HERD default (Cal/EPA, 2005c; 2009a)




Table 3. Johnson and Ettinger Model Input Data – Residential Scenario

Parameter Symbol Slab-on-grade Units Reference

Building PropertiesDepth below grade to bottom of enclosed space floor LF 15 cm DTSC/HERD default (Cal/EPA, 2005c; 2009a)

Building height H 244 cm USEPA default (USEPA, 2004a)

Building area A 1.0E+06 cm2 DTSC/HERD default (Cal/EPA, 2005c; 2009a)

Area of enclosed space below grade Ab 1.0E+06 cm2 DTSC/HERD default (Cal/EPA, 2009a)

Building air exchange rate AXRb 0.5 hr-1 DTSC default (Cal/EPA, 2005c; 2009a)

Vapor flow rate into building Qsoil 5 L/min DTSC/HERD default (Cal/EPA, 2005c; 2009a)

Soil Properties

Average soil temperature Ts 17 oC Site-specific (Cal/EPA, 2005c)

Dry bulk density ρb 1.50 g/cm3 DTSC/HERD default (Cal/EPA, 2005c; 2009a)

Total porosity η 0.430 cm3/cm3 DTSC/HERD default (Cal/EPA, 2009a)

Water-filled porosity θw 0.150 cm3/cm3 DTSC/HERD default (Cal/EPA, 2005c; 2009a)




Table 4. Physicochemical Properties

Chemical of Potential Concern Value Source Value Source Value Source Value Source Value Source Value Source Value Source Value Source Value Source Value Source Value Source

(cm2/s) (cm2/s) (atm-m3/mol) (oC) (cal/mol) (oK) (oK) (cal/mol) (atm-m3/mol) (unitless) (cm2/s)

Total Petroleum Hydrocarbons (TPH)

C5-C8 Aliphatic 1.00E-01 3 1.00E-05 3 8.00E-01 3 25 3 7.00E+03 3 369.00 3 508.00 3 8.42E+03 J&E 5.41E-01 J&E 2.27E+01 J&E 7.80E-03 J&E

C9-C12 Aliphatic 1.00E-01 3 1.00E-05 3 1.90E+00 3 25 3 7.00E+03 3 473.00 3 568.90 3 1.08E+04 J&E 1.15E+00 J&E 4.82E+01 J&E 7.80E-03 J&E

C9-C10 Aromatic 1.00E-01 3 1.00E-05 3 1.20E-02 3 25 3 9.32E+03 3 473.00 3 637.00 3 1.27E+04 J&E 6.65E-03 J&E 2.79E-01 J&E 7.80E-03 J&E

Volatile Organic Compounds (VOCs)

Acetone 1.24E-01 1 1.14E-05 1 3.87E-05 1 25 1 6.96E+03 1 329.20 1 508.10 1 7.47E+03 J&E 2.73E-05 J&E 1.15E-03 J&E 9.77E-03 J&E

Benzene 8.80E-02 1 9.80E-06 1 5.54E-03 1 25 1 7.34E+03 1 353.24 1 562.16 1 8.05E+03 J&E 3.81E-03 J&E 1.60E-01 J&E 6.86E-03 J&E

Bromodichloromethane 2.98E-02 1 1.06E-05 1 1.60E-03 1 25 1 7.80E+03 1 363.15 1 585.85 1 8.60E+03 J&E 1.07E-03 J&E 4.49E-02 J&E 2.33E-03 J&E

2-Butanone (methyl ethyl ketone) 8.08E-02 1 9.80E-06 1 5.58E-05 1 25 1 7.48E+03 1 352.50 1 536.78 1 8.33E+03 J&E 3.78E-05 J&E 1.59E-03 J&E 6.36E-03 J&E

n-Butylbenzene 5.70E-02 1 8.12E-06 1 1.31E-02 1 25 1 9.29E+03 1 456.46 1 660.50 1 1.18E+04 J&E 7.59E-03 J&E 3.19E-01 J&E 4.45E-03 J&E

sec-Butylbenzene 5.70E-02 1 8.12E-06 1 1.39E-02 1 25 1 8.87E+04 1 446.50 1 679.00 1 1.07E+05 J&E 9.37E-05 J&E 3.94E-03 J&E 4.47E-03 J&E

tert-Butylbenzene 5.65E-02 1 8.02E-06 1 1.19E-02 1 25 1 8.98E+03 1 442.10 1 1220.00 1 9.47E+03 J&E 7.64E-03 J&E 3.21E-01 J&E 4.41E-03 J&E

Carbon disulfide 1.04E-01 1 1.00E-05 1 3.02E-02 1 25 1 6.39E+03 1 319.00 1 552.00 1 6.63E+03 J&E 2.22E-02 J&E 9.32E-01 J&E 8.11E-03 J&E

Chloroform 1.04E-01 1 1.00E-05 1 3.66E-03 1 25 1 6.99E+03 1 334.32 1 536.40 1 7.48E+03 J&E 2.58E-03 J&E 1.09E-01 J&E 8.11E-03 J&E

Cumene 6.50E-02 1 7.10E-06 1 1.16E+00 1 25 1 1.03E+04 1 425.56 1 631.10 1 1.25E+04 J&E 6.45E-01 J&E 2.71E+01 J&E 5.07E-03 J&E

Cymene 6.37E-02 4 7.33E-06 6 1.10E-02 4 25 4 NONE NONE 450.10 4 NONE NONE NA J&E 1.10E-02 J&E 4.62E-01 J&E 4.97E-03 J&E

Dichlorodifluoromethane (Freon 12) 6.65E-02 1 9.92E-06 1 3.42E-01 1 25 1 9.42E+03 1 243.20 1 384.95 1 8.18E+03 J&E 2.34E-01 J&E 9.82E+00 J&E 5.19E-03 J&E

Ethylbenzene 7.50E-02 1 7.80E-06 1 7.86E-03 1 25 1 8.50E+03 1 409.34 1 617.20 1 1.01E+04 J&E 4.92E-03 J&E 2.07E-01 J&E 5.85E-03 J&E

4-Ethyltoluene 6.81E-02 4 7.84E-06 6 5.01E-03 4 25 4 NONE NONE 433.15 4 NONE NONE NA J&E 5.01E-03 J&E 2.10E-01 J&E 5.31E-03 J&E

Methylene chloride 1.01E-01 1 1.17E-05 1 2.18E-03 1 25 1 6.71E+03 1 313.00 1 510.00 1 6.96E+03 J&E 1.58E-03 J&E 6.64E-02 J&E 7.88E-03 J&E

Naphthalene 5.90E-02 1 7.50E-06 1 4.82E-04 1 25 1 1.04E+04 1 491.14 1 748.40 1 1.28E+04 J&E 2.65E-04 J&E 1.11E-02 J&E 4.61E-03 J&E

n-Propylbenzene 6.01E-02 1 7.83E-06 1 1.07E-02 1 25 1 9.12E+03 1 432.20 1 630.00 1 1.13E+04 J&E 6.31E-03 J&E 2.65E-01 J&E 4.69E-03 J&E

Styrene 7.10E-02 1 8.00E-06 1 2.74E-03 1 25 1 8.74E+03 1 418.31 1 636.00 1 1.04E+04 J&E 1.69E-03 J&E 7.11E-02 J&E 5.54E-03 J&E

Toluene 8.70E-02 1 8.60E-06 1 6.62E-03 1 25 1 7.93E+03 1 383.78 1 591.79 1 9.08E+03 J&E 4.34E-03 J&E 1.82E-01 J&E 6.79E-03 J&E

Trichlorofluoromethane (Freon 11) 8.70E-02 1 9.70E-06 1 9.68E-02 1 25 1 6.00E+03 1 296.70 1 471.00 1 6.08E+03 J&E 7.29E-02 J&E 3.06E+00 J&E 6.79E-03 J&E

1,2,4-Trimethylbenzene 6.06E-02 1 7.92E-06 1 6.14E-03 1 25 1 9.37E+03 1 442.30 1 649.17 1 1.16E+04 J&E 3.58E-03 J&E 1.50E-01 J&E 4.73E-03 J&E

1,3,5-Trimethylbenzene 6.02E-02 1 8.67E-06 1 5.87E-03 1 25 1 9.32E+03 1 437.89 1 637.25 1 1.16E+04 J&E 3.42E-03 J&E 1.44E-01 J&E 4.70E-03 J&E

Xylenes 8.50E-02 2 9.90E-06 2 7.30E-03 5 25 5 8.66E+03 1b 417.60 1b 630.30 1b 1.03E+04 J&E 4.51E-03 J&E 1.90E-01 J&E 6.63E-03 J&E

Notes:

(a) Sources of physicochemical data are as follows.

1 –

2 –

3 – Evaluating Human Health Risks from Total Petroleum Hydrocarbons (TPH) (Cal/EPA, 2009b)

4 –

5 – Regional Water Quality Control Board (RWQCB). 2000. Risked Based Screening Levels. Table J. Physio-chemical and Toxicity Constants used in Models. August.

6 – USEPA. 2006. Water9, Version 3. June 29. URL: http://www.epa.gov/ttn/chief/software/water/water9_3.

J&E – Calculated by Johnson & Ettinger model

(b)

Johnson and Ettinger screening-level soil gas model contained in Excel spreadsheet “HERD_Soil_Gas_Screening_Model_2009_rev.xls”. Department of Toxic Substances Control (DTSC). Human and Ecological Risk Division (HERD). (Cal/EPA, 2009a)

Vadose Zone Effective Diffusion Coefficient

(DeffV)Diffusivity in Air

(Da) Diffusivity In Water

(Dw)

Physicochemical data shown in table for xylenes are those for p-xylene.

Regional Screening Levels for Chemical Contaminants at Superfund Sites (USEPA, 2009)

SRC PhysProp Database. 2003. Found at http://esc.syrres.com/interkow/physdemo.htm. And methods from Schwarzenback R. P. et al. 1993. Environmental Organic Chemistry. John Wiley and Sons, Inc., New York, NY.

Henry's Law Constant at Reference Temperature

(H)

Henry's Law Constant at Average Soil

Temperature (H'TS)

Henry's Law Constant at Average Soil

Temperature (HTS)

Henry's Law Constant Reference

Temperature (TR)

Normal Boiling Point (TB)

Critical Temperature (TC)

Enthalpy of Vaporization at The

Normal Boiling Point (DHv,b)

Enthalpy of Vaporization at Average Soil

Temperature(DHv,TS)





10 feet 15 feet 5 feet 15 feet


8.1E-04 4.3E-04 5.0E-04 2.1E-04

8.1E-04 4.3E-04 5.0E-04 2.1E-04

8.1E-04 4.3E-04 5.0E-04 2.1E-04

TPH-Gasoline 8.1E-04 4.3E-04 5.0E-04 2.1E-04


8.2E-04 4.8E-04 5.7E-04 2.6E-04

8.1E-04 4.0E-04 4.6E-04 1.9E-04

8.0E-04 2.0E-04 2.1E-04 7.3E-05

8.1E-04 3.9E-04 4.4E-04 1.8E-04

8.1E-04 3.2E-04 3.4E-04 1.3E-04

8.1E-04 3.2E-04 3.5E-04 1.3E-04

8.1E-04 3.2E-04 3.4E-04 1.3E-04

8.2E-04 4.4E-04 5.1E-04 2.2E-04

8.2E-04 4.4E-04 5.1E-04 2.2E-04

8.1E-04 3.4E-04 3.8E-04 1.5E-04

8.1E-04 3.4E-04 3.7E-04 1.5E-04

8.1E-04 3.5E-04 3.8E-04 1.5E-04

8.1E-04 3.7E-04 4.2E-04 1.7E-04

8.1E-04 3.5E-04 3.9E-04 1.5E-04

8.1E-04 4.3E-04 5.0E-04 2.2E-04

8.1E-04 3.2E-04 3.5E-04 1.4E-04

8.1E-04 3.3E-04 3.6E-04 1.4E-04

8.1E-04 3.6E-04 4.0E-04 1.6E-04

8.1E-04 4.0E-04 4.6E-04 1.9E-04

8.1E-04 4.0E-04 4.6E-04 1.9E-04

8.1E-04 3.3E-04 3.6E-04 1.4E-04

8.1E-04 3.3E-04 3.6E-04 1.4E-04

8.1E-04 4.0E-04 4.5E-04 1.9E-04

Benzene

Bromodichloromethane

Dichlorodifluoromethane (Freon 12)

sec-Butylbenzene

tert-Butylbenzene

Cumene

Cymene

Carbon disulfide

Naphthalene

C5-C8 Aliphatic

Ethylbenzene

4-Ethyltoluene

Chemical of Potential Concern

Acetone

C9-C12 Aliphatic

C9-C10 Aromatic

2-Butanone (methyl ethyl ketone)

n-Butylbenzene

n-Propylbenzene

Styrene

Chloroform

Methylene chloride

Toluene

Trichlorofluoromethane (Freon 11)

1,2,4-Trimethylbenzene


Xylenes

Basement Slab-on-grade





10 feet 15 feet 5 feet 15 feetChemical of Potential Concern

Basement Slab-on-grade

Notes:

(1)

α = CIA / CSG

(2)

(3)

where:

αnc,TPH-g = noncancer-based target concentration for TPH-g (µg/m3);

xi = mass fraction of TPH-g within subgroup i (unitless); and

αnc,I = noncancer-based target concentration for subgroup i (µg/m3).

The the attenuation factor (α) for TPH-g is calculated as a weighted average of the attenuation factors for the TPH-g subgroups by the following equation (see text for details):

Attenuation factors at depth are calculated with the USEPA-recommended Johnson & Ettinger Model for soil gas (SG-SCREEN Version 2.0), as modified by DTSC/HERD (Johnson and Ettinger, 1991; USEPA, 2004; Cal/EPA, 2009a), and as modified by Iris Environmental.

where CIA is the chemical concentration in indoor air resulting from vapor intrusion, and CSG is the chemical concentration in soil gas at the specified depth.

By definition, the attenuation factor (α) is the ratio of the chemical concentration in indoor air (resulting from vapor intrusion) to the chemical concentration in soil gas beneath the building at the specified depth:

∑∑=−

i

igTPHnc, x

αxα i





5 feet 15 feet


1.0E-03 4.3E-04

1.0E-03 4.3E-04

1.0E-03 4.3E-04

TPH-Gasoline 1.0E-03 4.3E-04


1.1E-03 5.2E-04

9.2E-04 3.9E-04

4.2E-04 1.5E-04

8.8E-04 3.6E-04

6.9E-04 2.6E-04

6.9E-04 2.7E-04

6.8E-04 2.6E-04

1.0E-03 4.4E-04

1.0E-03 4.4E-04

7.5E-04 3.0E-04

7.4E-04 2.9E-04

7.7E-04 3.0E-04

8.3E-04 3.4E-04

7.8E-04 3.1E-04

1.0E-03 4.3E-04

7.1E-04 2.7E-04

7.1E-04 2.8E-04

8.0E-04 3.2E-04

9.2E-04 3.8E-04

9.2E-04 3.8E-04

7.2E-04 2.8E-04

7.2E-04 2.8E-04

9.0E-04 3.7E-04

Slab-on-grade

Toluene




Xylenes

Carbon disulfide

Naphthalene

n-Propylbenzene

Styrene

C5-C8 Aliphatic

Ethylbenzene

4-Ethyltoluene


Acetone

C9-C12 Aliphatic

C9-C10 Aromatic


n-Butylbenzene

Chloroform

Benzene



sec-Butylbenzene

tert-Butylbenzene

Methylene chloride

Cumene

Cymene





5 feet 15 feet

Slab-on-grade


Notes:

(1)

α = CIA / CSG

(2)

(3)

where:

αnc,TPH-g = noncancer-based target concentration for TPH-g (µg/m3);

xi = mass fraction of TPH-g within subgroup i (unitless); and

αnc,I = noncancer-based target concentration for subgroup i (µg/m3).

The the attenuation factor (α) for TPH-g is calculated as a weighted average of the attenuation factors for the TPH-g subgroups by the following equation (see text for details):

where CIA is the chemical concentration in indoor air resulting from vapor intrusion, and CSG is the chemical concentration in soil gas at the specified depth.

By definition, the attenuation factor (α) is the ratio of the chemical concentration in indoor air (resulting from vapor intrusion) to the chemical concentration in soil gas beneath the building at the specified depth:

Attenuation factors at depth are calculated with the USEPA-recommended Johnson & Ettinger Model for soil gas (SG-SCREEN Version 2.0), as modified by DTSC/HERD (Johnson and Ettinger, 1991; USEPA, 2004; Cal/EPA, 2009a), and as modified by Iris Environmental.

∑∑=−

i

igTPHnc, x

αxα i




Table 7. Modeled Indoor Air Concentrations – Commercial Scenario

Sample ID► SG-1-5 SG-1A-5 SG-1A-9 SG-2-5 SG-2-15 SG-2A-5 SG-2A-15 SG-3-5 SG-3-15 SG-3A-5 SG-3A-15 SG-8-5 SG-8-15

Sample Date► 02/13/08 10/12/09 10/12/09 02/13/08 02/13/08 10/12/09 10/12/09 02/13/08 02/13/08 10/12/09 10/12/09 10/12/09 10/12/09(µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3) (µg/m3)

TPH-Gasoline NS 4.2E+00 7.4E-01 NS NS 3.3E-03 1.7E-03 NS NS 5.1E+00 1.7E-03 2.0E-03 8.6E-04

Acetone NS 2.0E-02 NS 2.6E-02 NS NS NS NS NS NS NS NS NS

Benzene 1.6E-03 1.8E-03 1.8E-03 2.4E-02 1.4E-03 3.3E-03 1.6E-03 2.8E-03 1.4E-03 3.3E-03 1.6E-03 1.8E-03 7.7E-04

Bromodichloromethane 7.3E-04 6.2E-03 8.3E-04 8.0E-04 7.1E-04 3.2E-03 8.1E-04 2.8E-03 7.1E-04 3.2E-03 8.1E-04 8.3E-04 2.9E-04

2-Butanone (methyl ethyl ketone) NS 6.6E-03 NS 4.5E-03 NS NS NS NS NS NS NS NS NS

n-Butylbenzene 1.2E-03 2.0E-02 1.4E-03 2.8E-03 1.1E-03 3.2E-03 1.3E-03 2.8E-03 1.1E-03 3.2E-03 1.3E-03 1.4E-03 5.3E-04

sec-Butylbenzene 1.2E-03 4.8E-02 1.4E-03 2.8E-03 1.1E-03 3.2E-03 1.3E-03 2.8E-03 1.1E-03 3.2E-03 1.3E-03 1.4E-03 5.3E-04

tert-Butylbenzene 1.2E-03 1.4E-03 1.4E-03 2.8E-03 1.1E-03 3.2E-03 1.3E-03 2.8E-03 1.1E-03 3.2E-03 1.3E-03 1.4E-03 5.3E-04

Carbon disulfide NS 7.9E-03 NS 1.5E-02 NS NS NS NS NS NS NS NS NS

Chloroform 1.8E-03 2.9E-01 2.0E-03 6.1E-04 1.5E-03 3.3E-03 1.8E-03 2.9E-03 1.5E-03 3.3E-03 1.8E-03 2.0E-03 8.9E-04

Cumene 1.3E-03 9.4E-03 1.5E-03 2.8E-03 1.2E-03 3.2E-03 1.4E-03 2.8E-03 1.2E-03 3.2E-03 1.4E-03 1.5E-03 5.9E-04

Cymene 1.3E-03 1.6E-02 1.5E-03 2.8E-03 1.2E-03 3.2E-03 1.4E-03 2.8E-03 1.2E-03 3.2E-03 1.4E-03 1.5E-03 5.8E-04

Dichlorodifluoromethane (Freon 12) 1.3E-03 1.5E-03 1.5E-03 3.1E-03 1.2E-03 3.2E-03 1.4E-03 2.8E-03 1.2E-03 3.2E-03 1.4E-03 1.5E-03 6.1E-04

Ethylbenzene 1.5E-03 7.5E-03 1.7E-03 3.6E-03 1.3E-03 3.3E-03 1.5E-03 2.8E-03 1.3E-03 3.3E-03 1.5E-03 1.7E-03 6.7E-04

4-Ethyltoluene NS 1.9E-03 NS 3.3E-03 NS NS NS NS NS NS NS NS NS

Methylene chloride 1.8E-03 5.5E-03 2.0E-03 1.3E-03 1.5E-03 3.3E-03 1.7E-03 2.9E-03 1.5E-03 3.3E-03 1.7E-03 2.0E-03 8.7E-04

Naphthalene 1.2E-03 1.4E-03 1.4E-03 1.1E-03 1.1E-03 3.2E-03 1.3E-03 2.8E-03 1.1E-03 3.2E-03 1.3E-03 1.4E-03 5.5E-04

n-Propylbenzene 1.3E-03 1.4E-03 1.4E-03 2.8E-03 1.1E-03 3.2E-03 1.3E-03 2.8E-03 1.1E-03 3.2E-03 1.3E-03 1.4E-03 5.6E-04

Styrene 1.4E-03 1.6E-03 1.6E-03 2.8E-06 1.3E-03 3.3E-03 1.4E-03 2.8E-03 1.3E-03 3.3E-03 1.4E-03 1.6E-03 6.4E-04

Toluene 5.9E-03 5.9E-03 1.8E-01 3.3E-02 1.5E-02 3.3E-03 1.6E-03 3.4E-02 3.3E-02 2.5E+00 1.6E-03 1.8E-03 7.6E-04

Trichlorofluoromethane (Freon 11) 1.6E-03 1.8E-03 1.8E-03 2.2E-03 1.4E-03 3.3E-03 1.6E-03 2.8E-03 1.4E-03 3.3E-03 1.6E-03 1.8E-03 7.6E-04

1,2,4-Trimethylbenzene 1.3E-03 5.1E-02 1.4E-03 4.1E-03 1.2E-03 3.2E-03 1.3E-03 2.8E-03 1.2E-03 3.2E-03 1.3E-03 1.4E-03 5.6E-04


Xylenes 1.6E-03 9.1E-02 3.8E-02 2.0E-02 1.4E-03 3.3E-03 1.6E-03 2.8E-03 1.4E-03 3.3E-03 1.6E-03 1.8E-03 7.5E-04

Notes:

(1) Concentration units are micrograms per cubic meter (µg/m3).





Table 8. Modeled Indoor Air Concentrations – Residential Scenario

Sample ID► SG-1-5 SG-1A-5 SG-1A-9 SG-2-5 SG-2-15 SG-2A-5 SG-2A-15 SG-3-5 SG-3-15 SG-3A-5 SG-3A-15 SG-4-5 SG-4-15 SG-4A-5 SG-4A-15 SG-5-5 SG-5-15 SG-5A-5 SG-5A-15 SG-6-5 SG-6-15 SG-6A-5 SG-6A-15 SG-7-5 SG-7-15 SG-8-5 SG-8-15 SG-9-5 SG-9-15 SG-10-5 SG-10-15

Sample Date► 02/13/08 10/12/09 10/12/09 02/13/08 02/13/08 10/12/09 10/12/09 02/13/08 02/13/08 10/12/09 10/12/09 02/12/08 02/12/08 10/12/09 10/12/09 02/13/08 02/12/08 10/12/09 10/12/09 02/12/08 02/12/08 10/12/09 10/12/09 02/12/08 02/12/08 10/12/09 10/12/09 10/12/09 10/12/09 10/12/09 10/12/09

TPH-Gasoline NS 8.5E+00 1.5E+00 NS NS 4.0E-03 1.7E-03 NS NS 6.3E+00 1.7E-03 NS NS 1.5E+01 2.7E+03 NS NS 9.5E-01 7.5E+00 NS NS 1.9E+01 4.1E+02 NS NS 4.0E-03 1.7E-03 1.8E-01 2.7E+00 1.3E+00 1.7E+00

Acetone NS 4.1E-02 NS 3.6E-02 NS NS NS NS NS NS NS 2.9E-02 NS NS 3.1E+00 NS NS NS NS NS NS 1.6E-02 NS NS NS NS NS NS NS NS NS

Benzene 3.2E-03 3.7E-03 3.7E-03 2.8E-02 1.4E-03 3.7E-03 1.5E-03 3.2E-03 1.4E-03 3.7E-03 1.5E-03 5.3E-01 1.6E+01 3.7E-03 1.0E+01 3.2E-03 8.3E-02 3.7E-03 4.2E-02 5.6E-01 7.4E+00 1.5E-02 1.4E+00 4.7E-02 4.6E-01 3.7E-03 1.5E-03 3.7E-03 1.5E-03 4.6E-02 3.9E-03

Bromodichloromethane 1.5E-03 1.2E-02 1.7E-03 4.2E-04 5.1E-04 1.7E-03 5.8E-04 1.5E-03 5.1E-04 1.7E-03 5.8E-04 8.3E-04 5.1E-03 1.7E-03 5.8E-03 1.5E-03 1.3E-03 1.7E-03 5.8E-04 3.7E-03 1.3E-03 1.7E-03 1.5E-03 3.7E-03 1.3E-03 1.7E-03 5.8E-04 1.7E-03 5.8E-04 1.7E-03 1.5E-03

2-Butanone (methyl ethyl ketone) NS 1.3E-02 NS 4.8E-03 NS NS NS NS NS NS NS 2.5E-03 NS NS 2.7E+00 NS NS NS NS NS NS 1.5E-02 NS NS NS NS NS NS NS NS NS

n-Butylbenzene 2.4E-03 4.1E-02 2.8E-03 2.4E-03 9.3E-04 2.8E-03 1.1E-03 2.4E-03 9.3E-04 2.8E-03 1.1E-03 6.2E-03 9.3E-03 4.1E-02 1.1E-02 2.4E-03 2.4E-03 3.9E-02 1.1E-03 6.2E-03 2.4E-03 5.2E-02 2.6E-03 6.2E-03 2.4E-03 2.8E-03 1.1E-03 2.8E-03 1.1E-03 4.1E-02 2.6E-03

sec-Butylbenzene 2.4E-03 9.7E-02 2.8E-03 2.4E-03 9.3E-04 2.8E-03 1.1E-03 2.4E-03 9.3E-04 2.8E-03 1.1E-03 6.2E-03 9.3E-03 1.0E-01 1.1E-02 2.4E-03 2.4E-03 2.8E-03 1.1E-03 6.2E-03 2.4E-03 2.1E-01 2.7E-03 6.2E-03 2.4E-03 2.8E-03 1.1E-03 5.0E-02 1.1E-03 8.3E-02 2.7E-03

tert-Butylbenzene 2.4E-03 2.7E-03 2.7E-03 2.4E-03 9.2E-04 2.7E-03 1.1E-03 2.4E-03 9.2E-04 2.7E-03 1.1E-03 6.2E-03 9.2E-03 2.7E-03 1.5E+00 2.4E-03 2.4E-03 7.0E-02 2.8E-02 6.2E-03 2.4E-03 2.7E-03 2.6E-01 6.2E-03 2.4E-03 2.7E-03 1.1E-03 2.7E-03 1.1E-03 2.7E-03 2.6E-03

Carbon disulfide NS 1.6E-02 NS 1.9E-02 NS NS NS NS NS NS NS 8.6E-03 NS NS 3.5E+00 NS NS NS NS NS NS 1.8E-02 NS NS NS NS NS NS NS NS NS

Chloroform 3.6E-03 5.7E-01 4.1E-03 7.6E-04 1.6E-03 4.1E-03 1.8E-03 3.6E-03 1.6E-03 4.1E-03 1.8E-03 1.5E-03 1.6E-02 4.1E-03 1.8E-02 3.6E-03 4.0E-03 1.4E-01 4.0E-03 9.2E-03 4.0E-03 4.1E-03 4.4E-03 9.2E-03 4.0E-03 4.1E-03 1.8E-03 4.1E-03 1.8E-03 4.1E-03 4.4E-03

Cumene 2.6E-03 1.9E-02 3.0E-03 2.6E-03 1.0E-03 3.0E-03 1.2E-03 2.6E-03 1.0E-03 3.0E-03 1.2E-03 6.8E-03 4.9E-01 2.3E-02 7.7E+00 2.6E-03 2.7E-03 1.6E-02 1.9E-01 6.8E-03 1.3E-01 7.2E-02 2.9E+00 6.8E-03 2.7E-03 3.0E-03 1.2E-03 3.0E-03 1.2E-03 1.8E-02 3.0E-03

Cymene 2.6E-03 3.2E-02 3.0E-03 2.6E-03 1.0E-03 3.0E-03 1.2E-03 2.6E-03 1.0E-03 3.0E-03 1.2E-03 6.7E-03 1.0E-02 5.8E-02 1.2E-02 2.6E-03 2.6E-03 3.3E-02 1.2E-03 6.7E-03 2.6E-03 4.2E-02 2.9E-03 6.7E-03 2.6E-03 3.0E-03 1.2E-03 3.6E-02 1.2E-03 6.7E-02 2.9E-03

Dichlorodifluoromethane (Freon 12) 2.7E-03 3.1E-03 3.1E-03 2.9E-03 1.1E-03 3.1E-03 1.2E-03 2.7E-03 1.1E-03 3.1E-03 1.2E-03 1.1E-03 1.1E-02 3.1E-03 1.2E-02 2.7E-03 2.7E-03 3.1E-03 1.2E-03 6.9E-03 2.7E-03 3.1E-03 3.0E-03 6.9E-03 2.7E-03 3.1E-03 1.2E-03 3.1E-03 1.2E-03 3.1E-03 3.0E-03

Ethylbenzene 2.9E-03 1.5E-02 3.3E-03 3.7E-03 1.2E-03 3.3E-03 1.3E-03 2.9E-03 1.2E-03 3.3E-03 1.3E-03 4.4E-01 8.9E+00 5.6E-01 9.5E+01 2.9E-03 3.0E-03 3.3E-03 4.2E-02 7.8E-01 3.5E+00 5.4E-01 1.5E+01 1.0E+00 1.2E-01 3.3E-03 1.3E-03 3.3E-03 1.3E-03 1.7E-01 3.4E-03

4-Ethyltoluene NS 3.8E-03 NS 3.1E-03 NS NS NS NS NS NS NS 3.6E-02 NS NS 4.3E+01 NS NS NS NS NS NS 6.9E-02 NS NS NS NS NS NS NS NS NS

Methylene chloride 3.5E-03 1.1E-02 4.0E-03 1.6E-03 1.5E-03 4.0E-03 1.7E-03 3.5E-03 1.5E-03 4.0E-03 1.7E-03 1.0E-03 1.5E-02 4.0E-03 1.7E-02 3.5E-03 3.9E-03 4.0E-03 1.7E-03 9.0E-03 3.9E-03 9.6E-03 4.3E-03 9.0E-03 3.9E-03 4.0E-03 1.7E-03 4.0E-03 1.7E-03 4.0E-03 4.3E-03

Naphthalene 2.5E-03 2.8E-03 2.8E-03 9.2E-04 9.6E-04 2.8E-03 1.1E-03 2.5E-03 9.6E-04 2.8E-03 1.1E-03 1.8E-03 9.6E-03 2.8E-03 2.3E+01 2.5E-03 2.5E-03 2.8E-03 9.6E-03 6.4E-03 2.5E-03 2.8E-03 5.4E+00 6.4E-03 2.5E-03 2.8E-03 1.1E-03 2.8E-03 1.1E-03 2.8E-03 2.7E-03

n-Propylbenzene 2.5E-03 2.9E-03 2.9E-03 2.5E-03 9.7E-04 2.9E-03 1.1E-03 2.5E-03 9.7E-04 2.9E-03 1.1E-03 6.4E-03 9.7E-03 2.9E-03 1.1E-02 2.5E-03 2.5E-03 2.9E-03 1.1E-03 6.4E-03 2.5E-03 1.5E-02 2.8E-03 6.4E-03 2.5E-03 2.9E-03 1.1E-03 2.9E-03 1.1E-03 2.9E-03 2.8E-03

Styrene 2.8E-03 3.2E-03 3.2E-03 2.8E-06 1.1E-03 3.2E-03 1.3E-03 2.8E-03 1.1E-03 3.2E-03 1.3E-03 2.4E-05 1.1E-02 3.2E-03 2.0E+01 2.8E-03 2.9E-03 3.2E-03 1.3E-03 7.2E-03 2.9E-03 3.2E-03 3.2E-03 7.2E-03 2.9E-03 3.2E-03 1.3E-03 3.2E-03 1.3E-03 3.2E-03 3.2E-03

Toluene 1.2E-02 1.2E-02 3.7E-01 3.8E-02 1.4E-02 3.7E-03 1.5E-03 3.8E-02 3.2E-02 2.9E+00 1.5E-03 8.6E+00 1.7E+02 2.7E-01 5.0E+02 5.4E-02 6.0E-01 1.1E-01 8.1E-02 5.5E+00 3.8E+01 1.3E-01 2.7E+01 1.8E+00 2.7E+00 3.7E-03 1.5E-03 3.7E-03 1.5E-03 1.2E-01 3.8E-03

Trichlorofluoromethane (Freon 11) 3.2E-03 3.7E-03 3.7E-03 2.5E-03 1.3E-03 3.7E-03 1.5E-03 3.2E-03 1.3E-03 3.7E-03 1.5E-03 2.0E-03 1.3E-02 3.7E-03 1.5E-02 3.2E-03 3.4E-03 3.7E-03 1.5E-03 8.2E-03 3.4E-03 3.7E-03 3.8E-03 8.2E-03 3.4E-03 3.7E-03 1.5E-03 3.7E-03 1.5E-03 3.7E-03 3.8E-03

1,2,4-Trimethylbenzene 2.5E-03 1.0E-01 2.9E-03 3.7E-03 9.8E-04 2.9E-03 1.1E-03 2.5E-03 9.8E-04 2.9E-03 1.1E-03 2.4E-02 3.2E-01 1.1E-01 3.2E+01 2.5E-03 2.5E-03 8.6E-02 1.3E-02 6.5E-03 2.5E-03 2.5E-01 3.1E+00 6.5E-03 2.5E-03 2.9E-03 1.1E-03 4.2E-02 1.1E-03 8.1E-02 2.8E-03

1,3,5-Trimethylbenzene 2.5E-03 1.5E-02 2.9E-03 8.6E-04 9.7E-04 2.9E-03 1.1E-03 2.5E-03 9.7E-04 2.9E-03 1.1E-03 1.8E-02 3.4E-01 4.8E-02 4.4E+01 2.5E-03 2.5E-03 1.9E-02 1.4E-02 6.4E-03 2.5E-03 1.3E-01 8.2E+00 6.4E-03 2.5E-03 2.9E-03 1.1E-03 2.9E-03 1.1E-03 2.1E-02 2.8E-03

Xylenes 3.2E-03 1.8E-01 7.7E-02 2.2E-02 1.3E-03 3.6E-03 1.5E-03 3.2E-03 1.3E-03 3.6E-03 1.5E-03 2.8E+00 4.9E+01 9.5E-01 8.1E+02 3.2E-03 3.4E-03 2.9E-01 2.0E-01 5.4E+00 9.3E+00 1.0E+00 9.7E+01 1.4E+01 4.1E-01 3.6E-03 1.5E-03 3.2E-03 1.3E-03 2.6E-01 7.7E-02

Notes:

(1) Concentration units are micrograms per cubic meter (µg/m3).






Chemical of Potential Concern Value Source Value Source

(per µg/m3) (µg/m3)


NC NC 7.0E+02 5

NC NC 3.0E+02 5

NC NC 5.0E+01 5

TPH-Gasoline NC NC 2.9E+02 5c


NC NC 3.1E+04 3

2.9E-05 1 3.0E+01 2

3.7E-05 1 7.0E+01 2R

NC NC 5.0E+03 2

NC NC 1.4E+02 4R

NC NC 1.4E+02 4R

NC NC 1.4E+02 4R

NC NC 7.0E+02 25.3E-06 1 3.0E+02 1

NC NC 4.0E+02 2NC NC 4.0E+02 2aNC NC 2.0E+02 3

2.5E-06 1 1.0E+03 2NC NC 1.0E+02 2b

1.0E-06 1 4.0E+02 13.4E-05 1 3.0E+00 2

NC NC 1.0E+03 3NC NC 9.0E+02 1NC NC 3.0E+02 1

NC NC 7.0E+02 3

NC NC 7.0E+00 3

NC NC 3.5E+01 3

NC NC 1.0E+02 2

Benzene


C9-C10 Aromatic

Cymene

n-Butylbenzene

sec-Butylbenzene

4-Ethyltoluene

tert-Butylbenzene

Carbon disulfide

Methylene chloride

Naphthalene

n-Propylbenzene

Styrene

Toluene

Acetone



Chloroform

Cumene

Ethylbenzene




Xylenes

C5-C8 Aliphatic

C9-C12 Aliphatic

Unit Risk Factor (URF)

Reference Concentration(RfC)





Chemical of Potential Concern Value Source Value Source

(per µg/m3) (µg/m3)

Unit Risk Factor (URF)

Reference Concentration(RfC)

Notes:

(a) Sources of toxicity data are as follows.

1 –

2 –

3 –

4 –

5 –

a –

b –

R –

(b)

(c)

RfCnc,TPH-g =

xi =

RfCnc,i =

Cumene is used as a surrogate.

Xylenes is used as a surrogate.

Route-to-route extrapolation of the oral toxicity value

Integrated Risk Information System (IRIS) (USEPA, 2010)

Regional Screening Levels for Chemical Contaminants at Superfund Sites (USEPA, 2009)

Region 9 PRG Table (USEPA, 2004b)

Evaluating Human Health Risks from Total Petroleum Hydrocarbons (TPH) (Cal/EPA, 2009b)

OEHHA Toxicity Criteria Database (Cal/EPA, 2010)

"NC" indicates that the chemical is classified as a noncarcinogen for the inhalation pathway.

The reference concentration for TPH-g is calculated as a weighted average of the reference concentrations for the TPH-g subgroups by the following equation (see text for details):

where:

noncancer-based target concentration for TPH-g (µg/m3);

mass fraction of TPH-g within subgroup i (unitless); and

noncancer-based target concentration for subgroup i (µg/m3).

∑=−

inc,

igTPHnc,

RfCx

1RfC




Table 10. Exposure Assumptions

Symbol Commercial/Industrial Residential Units

EF 250 350 d/yr

ED 25 30 yr

ATc 25,550 25,550 d

ATnc 9,125 10,950 d

Notes:

(1)

Parameter

Exposure assumptions are default values recommended by DTSC/HERD (Cal/EPA, 2005d).

Exposure frequency

Averaging time for carcinogenic effects

Averaging time for noncarcinogenic effects

Exposure duration




Table 11. Cancer Risk – Commercial Scenario


Sample Date► 02/13/08 10/12/09 10/12/09 02/13/08 02/13/08 10/12/09 10/12/09 02/13/08 02/13/08 10/12/09 10/12/09 10/12/09 10/12/09

TPH-Gasoline NS NC NC NS NS NC NC NS NS NC NC NC NC

Acetone NS NC NS NC NS NS NS NS NS NS NS NS NS



2-Butanone (methyl ethyl ketone) NS NC NS NC NS NS NS NS NS NS NS NS NS

n-Butylbenzene NC NC NC NC NC NC NC NC NC NC NC NC NC

sec-Butylbenzene NC NC NC NC NC NC NC NC NC NC NC NC NC

tert-Butylbenzene NC NC NC NC NC NC NC NC NC NC NC NC NC

Carbon disulfide NS NC NS NC NS NS NS NS NS NS NS NS NS


Cumene NC NC NC NC NC NC NC NC NC NC NC NC NC

Cymene NC NC NC NC NC NC NC NC NC NC NC NC NC

Dichlorodifluoromethane (Freon 12) NC NC NC NC NC NC NC NC NC NC NC NC NC


4-Ethyltoluene NS NC NS NC NS NS NS NS NS NS NS NS NS



n-Propylbenzene NC NC NC NC NC NC NC NC NC NC NC NC NC

Styrene NC NC NC NC NC NC NC NC NC NC NC NC NC

Toluene NC NC NC NC NC NC NC NC NC NC NC NC NC

Trichlorofluoromethane (Freon 11) NC NC NC NC NC NC NC NC NC NC NC NC NC

1,2,4-Trimethylbenzene NC NC NC NC NC NC NC NC NC NC NC NC NC

1,3,5-Trimethylbenzene NC NC NC NC NC NC NC NC NC NC NC NC NC

Xylenes NC NC NC NC NC NC NC NC NC NC NC NC NC

Cumulative (multi-chemical) 3.2E-08 4.6E-07 3.6E-08 1.9E-07 2.9E-08 8.6E-08 3.3E-08 7.5E-08 2.9E-08 8.6E-08 3.3E-08 3.6E-08 1.4E-08

Notes:


(2) "NC" indicates chemical is noncarcinogenic.




Table 12. Cancer Risk – Residential Scenario


Sample Date► 02/13/08 10/12/09 10/12/09 02/13/08 02/13/08 10/12/09 10/12/09 02/13/08 02/13/08 10/12/09 10/12/09 02/12/08 02/12/08 10/12/09 10/12/09 02/13/08 02/12/08 10/12/09 10/12/09 02/12/08 02/12/08 10/12/09 10/12/09 02/12/08 02/12/08 10/12/09 10/12/09 10/12/09 10/12/09 10/12/09 10/12/09

TPH-Gasoline NS NC NC NS NS NC NC NS NS NC NC NS NS NC NC NS NS NC NC NS NS NC NC NS NS NC NC NC NC NC NC

Acetone NS NC NS NC NS NS NS NS NS NS NS NC NS NS NC NS NS NS NS NS NS NC NS NS NS NS NS NS NS NS NS

Benzene 3.8E-08 4.4E-08 4.4E-08 3.3E-07 1.6E-08 4.4E-08 1.8E-08 3.8E-08 1.6E-08 4.4E-08 1.8E-08 6.3E-06 1.9E-04 4.4E-08 1.2E-04 3.8E-08 9.8E-07 4.4E-08 5.0E-07 6.7E-06 8.8E-05 1.8E-07 1.6E-05 5.6E-07 5.5E-06 4.4E-08 1.8E-08 4.4E-08 1.8E-08 5.5E-07 4.6E-08


2-Butanone (methyl ethyl ketone) NS NC NS NC NS NS NS NS NS NS NS NC NS NS NC NS NS NS NS NS NS NC NS NS NS NS NS NS NS NS NS

n-Butylbenzene NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC

sec-Butylbenzene NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC

tert-Butylbenzene NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC

Carbon disulfide NS NC NS NC NS NS NS NS NS NS NS NC NS NS NC NS NS NS NS NS NS NC NS NS NS NS NS NS NS NS NS


Cumene NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC

Cymene NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC

Dichlorodifluoromethane (Freon 12) NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC

Ethylbenzene 3.0E-09 1.5E-08 3.4E-09 3.8E-09 1.2E-09 3.4E-09 1.4E-09 3.0E-09 1.2E-09 3.4E-09 1.4E-09 4.5E-07 9.2E-06 5.7E-07 9.8E-05 3.0E-09 3.1E-09 3.4E-09 4.3E-08 8.0E-07 3.6E-06 5.5E-07 1.5E-05 1.1E-06 1.2E-07 3.4E-09 1.4E-09 3.4E-09 1.4E-09 1.7E-07 3.5E-09

4-Ethyltoluene NS NC NS NC NS NS NS NS NS NS NS NC NS NS NC NS NS NS NS NS NS NC NS NS NS NS NS NS NS NS NS


Naphthalene 3.5E-08 3.9E-08 3.9E-08 1.3E-08 1.3E-08 3.9E-08 1.5E-08 3.5E-08 1.3E-08 3.9E-08 1.5E-08 2.6E-08 1.3E-07 3.9E-08 3.3E-04 3.5E-08 3.4E-08 3.9E-08 1.3E-07 8.9E-08 3.4E-08 3.9E-08 7.5E-05 8.9E-08 3.4E-08 3.9E-08 1.5E-08 3.9E-08 1.5E-08 3.9E-08 3.8E-08

n-Propylbenzene NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC

Styrene NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC

Toluene NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC

Trichlorofluoromethane (Freon 11) NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC

1,2,4-Trimethylbenzene NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC

1,3,5-Trimethylbenzene NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC

Xylenes NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC NC

Cumulative (multi-chemical) 1.1E-07 1.5E-06 1.2E-07 3.5E-07 4.2E-08 1.2E-07 4.9E-08 1.1E-07 4.2E-08 1.2E-07 4.9E-08 6.8E-06 2.0E-04 6.9E-07 5.5E-04 1.1E-07 1.1E-06 4.3E-07 7.0E-07 7.7E-06 9.2E-05 8.1E-07 1.1E-04 1.8E-06 5.7E-06 1.2E-07 4.9E-08 1.2E-07 4.9E-08 8.0E-07 1.2E-07

Notes:


(2) "NC" indicates chemical is noncarcinogenic.




Table 13. Noncancer Hazard – Commercial


Sample Date► 02/13/08 10/12/09 10/12/09 02/13/08 02/13/08 10/12/09 10/12/09 02/13/08 02/13/08 10/12/09 10/12/09 10/12/09 10/12/09

TPH-Gasoline NS 1.0E-02 1.8E-03 NS NS 7.7E-06 4.1E-06 NS NS 1.2E-02 4.1E-06 4.7E-06 2.0E-06

Acetone NS 4.5E-07 NS 5.8E-07 NS NS NS NS NS NS NS NS NS



2-Butanone (methyl ethyl ketone) NS 9.0E-07 NS 6.1E-07 NS NS NS NS NS NS NS NS NS

n-Butylbenzene 5.9E-06 9.9E-05 6.7E-06 1.4E-05 5.4E-06 1.6E-05 6.2E-06 1.4E-05 5.4E-06 1.6E-05 6.2E-06 6.7E-06 2.6E-06

sec-Butylbenzene 5.9E-06 2.4E-04 6.8E-06 1.4E-05 5.4E-06 1.6E-05 6.2E-06 1.4E-05 5.4E-06 1.6E-05 6.2E-06 6.8E-06 2.6E-06

tert-Butylbenzene 5.9E-06 6.7E-06 6.7E-06 1.4E-05 5.4E-06 1.6E-05 6.2E-06 1.4E-05 5.4E-06 1.6E-05 6.2E-06 6.7E-06 2.6E-06

Carbon disulfide NS 7.7E-06 NS 1.5E-05 NS NS NS NS NS NS NS NS NS


Cumene 2.3E-06 1.6E-05 2.6E-06 4.9E-06 2.1E-06 5.6E-06 2.3E-06 4.9E-06 2.1E-06 5.6E-06 2.3E-06 2.6E-06 1.0E-06

Cymene 2.2E-06 2.7E-05 2.5E-06 4.9E-06 2.0E-06 5.6E-06 2.3E-06 4.9E-06 2.0E-06 5.6E-06 2.3E-06 2.5E-06 1.0E-06

Dichlorodifluoromethane (Freon 12) 4.6E-06 5.3E-06 5.3E-06 1.1E-05 4.2E-06 1.1E-05 4.8E-06 9.7E-06 4.2E-06 1.1E-05 4.8E-06 5.3E-06 2.1E-06


4-Ethyltoluene NS 1.3E-05 NS 2.2E-05 NS NS NS NS NS NS NS NS NS



n-Propylbenzene 8.6E-07 9.8E-07 9.8E-07 1.9E-06 7.9E-07 2.2E-06 9.0E-07 1.9E-06 7.9E-07 2.2E-06 9.0E-07 9.8E-07 3.8E-07

Styrene 1.1E-06 1.2E-06 1.2E-06 2.2E-09 9.6E-07 2.5E-06 1.1E-06 2.2E-06 9.6E-07 2.5E-06 1.1E-06 1.2E-06 4.9E-07

Toluene 1.4E-05 1.4E-05 4.2E-04 7.6E-05 3.4E-05 7.4E-06 3.7E-06 7.8E-05 7.6E-05 5.8E-03 3.7E-06 4.2E-06 1.7E-06

Trichlorofluoromethane (Freon 11) 1.6E-06 1.8E-06 1.8E-06 2.2E-06 1.4E-06 3.2E-06 1.6E-06 2.8E-06 1.4E-06 3.2E-06 1.6E-06 1.8E-06 7.5E-07



Xylenes 1.1E-05 6.2E-04 2.6E-04 1.3E-04 9.5E-06 2.2E-05 1.1E-05 2.0E-05 9.5E-06 2.2E-05 1.1E-05 1.2E-05 5.1E-06

Cumulative (multi-chemical) 5.4E-04 1.7E-02 3.0E-03 1.6E-03 5.1E-04 1.4E-03 5.5E-04 1.3E-03 5.5E-04 1.9E-02 5.5E-04 6.1E-04 2.4E-04

Notes:





Table 14. Noncancer Hazard – Residential


Sample Date► 02/13/08 10/12/09 10/12/09 02/13/08 02/13/08 10/12/09 10/12/09 02/13/08 02/13/08 10/12/09 10/12/09 02/12/08 02/12/08 10/12/09 10/12/09 02/13/08 02/12/08 10/12/09 10/12/09 02/12/08 02/12/08 10/12/09 10/12/09 02/12/08 02/12/08 10/12/09 10/12/09 10/12/09 10/12/09 10/12/09 10/12/09

TPH-Gasoline NS 2.8E-02 4.9E-03 NS NS 1.3E-05 5.7E-06 NS NS 2.1E-02 5.7E-06 NS NS 5.1E-02 8.8E+00 NS NS 3.2E-03 2.5E-02 NS NS 6.3E-02 1.3E+00 NS NS 1.3E-05 5.7E-06 5.9E-04 8.8E-03 4.2E-03 5.7E-03

Acetone NS 1.3E-06 NS 1.1E-06 NS NS NS NS NS NS NS 9.1E-07 NS NS 9.6E-05 NS NS NS NS NS NS 4.9E-07 NS NS NS NS NS NS NS NS NS

Benzene 1.0E-04 1.2E-04 1.2E-04 8.8E-04 4.3E-05 1.2E-04 4.9E-05 1.0E-04 4.3E-05 1.2E-04 4.9E-05 1.7E-02 5.1E-01 1.2E-04 3.3E-01 1.0E-04 2.6E-03 1.2E-04 1.3E-03 1.8E-02 2.4E-01 4.7E-04 4.4E-02 1.5E-03 1.5E-02 1.2E-04 4.9E-05 1.2E-04 4.9E-05 1.5E-03 1.2E-04


2-Butanone (methyl ethyl ketone) NS 2.5E-06 NS 9.3E-07 NS NS NS NS NS NS NS 4.9E-07 NS NS 5.2E-04 NS NS NS NS NS NS 2.9E-06 NS NS NS NS NS NS NS NS NS

n-Butylbenzene 1.6E-05 2.8E-04 1.9E-05 1.6E-05 6.3E-06 1.9E-05 7.3E-06 1.6E-05 6.3E-06 1.9E-05 7.3E-06 4.2E-05 6.3E-05 2.8E-04 7.3E-05 1.6E-05 1.6E-05 2.7E-04 7.3E-06 4.2E-05 1.6E-05 3.6E-04 1.8E-05 4.2E-05 1.6E-05 1.9E-05 7.3E-06 1.9E-05 7.3E-06 2.8E-04 1.8E-05

sec-Butylbenzene 1.7E-05 6.6E-04 1.9E-05 1.7E-05 6.4E-06 1.9E-05 7.3E-06 1.7E-05 6.4E-06 1.9E-05 7.3E-06 4.3E-05 6.4E-05 6.9E-04 7.3E-05 1.7E-05 1.6E-05 1.9E-05 7.3E-06 4.3E-05 1.6E-05 1.4E-03 1.8E-05 4.3E-05 1.6E-05 1.9E-05 7.3E-06 3.5E-04 7.3E-06 5.7E-04 1.8E-05

tert-Butylbenzene 1.6E-05 1.9E-05 1.9E-05 1.6E-05 6.3E-06 1.9E-05 7.2E-06 1.6E-05 6.3E-06 1.9E-05 7.2E-06 4.2E-05 6.3E-05 1.9E-05 1.0E-02 1.6E-05 1.6E-05 4.8E-04 1.9E-04 4.2E-05 1.6E-05 1.9E-05 1.8E-03 4.2E-05 1.6E-05 1.9E-05 7.2E-06 1.9E-05 7.2E-06 1.9E-05 1.8E-05

Carbon disulfide NS 2.2E-05 NS 2.7E-05 NS NS NS NS NS NS NS 1.2E-05 NS NS 4.9E-03 NS NS NS NS NS NS 2.5E-05 NS NS NS NS NS NS NS NS NS


Cumene 6.3E-06 4.5E-05 7.2E-06 6.3E-06 2.5E-06 7.2E-06 2.9E-06 6.3E-06 2.5E-06 7.2E-06 2.9E-06 1.6E-05 1.2E-03 5.4E-05 1.8E-02 6.3E-06 6.4E-06 3.8E-05 4.6E-04 1.6E-05 3.1E-04 1.7E-04 7.0E-03 1.6E-05 6.4E-06 7.2E-06 2.9E-06 7.2E-06 2.9E-06 4.3E-05 7.1E-06

Cymene 6.2E-06 7.7E-05 7.1E-06 6.2E-06 2.5E-06 7.1E-06 2.8E-06 6.2E-06 2.5E-06 7.1E-06 2.8E-06 1.6E-05 2.5E-05 1.4E-04 2.8E-05 6.2E-06 6.3E-06 7.8E-05 2.8E-06 1.6E-05 6.3E-06 1.0E-04 7.0E-06 1.6E-05 6.3E-06 7.1E-06 2.8E-06 8.6E-05 2.8E-06 1.6E-04 7.0E-06

Dichlorodifluoromethane (Freon 12) 1.3E-05 1.5E-05 1.5E-05 1.4E-05 5.1E-06 1.5E-05 5.8E-06 1.3E-05 5.1E-06 1.5E-05 5.8E-06 5.5E-06 5.1E-05 1.5E-05 5.8E-05 1.3E-05 1.3E-05 1.5E-05 5.8E-06 3.3E-05 1.3E-05 1.5E-05 1.5E-05 3.3E-05 1.3E-05 1.5E-05 5.8E-06 1.5E-05 5.8E-06 1.5E-05 1.5E-05

Ethylbenzene 2.8E-06 1.4E-05 3.2E-06 3.5E-06 1.1E-06 3.2E-06 1.3E-06 2.8E-06 1.1E-06 3.2E-06 1.3E-06 4.2E-04 8.6E-03 5.4E-04 9.1E-02 2.8E-06 2.9E-06 3.2E-06 4.0E-05 7.5E-04 3.4E-03 5.2E-04 1.4E-02 1.0E-03 1.2E-04 3.2E-06 1.3E-06 3.2E-06 1.3E-06 1.6E-04 3.2E-06

4-Ethyltoluene NS 3.7E-05 NS 3.0E-05 NS NS NS NS NS NS NS 3.4E-04 NS NS 4.2E-01 NS NS NS NS NS NS 6.6E-04 NS NS NS NS NS NS NS NS NS


Naphthalene 7.9E-04 9.0E-04 9.0E-04 2.9E-04 3.1E-04 9.0E-04 3.5E-04 7.9E-04 3.1E-04 9.0E-04 3.5E-04 5.9E-04 3.1E-03 9.0E-04 7.5E+00 7.9E-04 7.9E-04 9.0E-04 3.1E-03 2.0E-03 7.9E-04 9.0E-04 1.7E+00 2.0E-03 7.9E-04 9.0E-04 3.5E-04 9.0E-04 3.5E-04 9.0E-04 8.7E-04

n-Propylbenzene 2.4E-06 2.7E-06 2.7E-06 2.4E-06 9.3E-07 2.7E-06 1.1E-06 2.4E-06 9.3E-07 2.7E-06 1.1E-06 6.2E-06 9.3E-06 2.7E-06 1.1E-05 2.4E-06 2.4E-06 2.7E-06 1.1E-06 6.2E-06 2.4E-06 1.4E-05 2.7E-06 6.2E-06 2.4E-06 2.7E-06 1.1E-06 2.7E-06 1.1E-06 2.7E-06 2.7E-06

Styrene 3.0E-06 3.4E-06 3.4E-06 3.0E-09 1.2E-06 3.4E-06 1.4E-06 3.0E-06 1.2E-06 3.4E-06 1.4E-06 2.6E-08 1.2E-05 3.4E-06 2.2E-02 3.0E-06 3.1E-06 3.4E-06 1.4E-06 7.7E-06 3.1E-06 3.4E-06 3.4E-06 7.7E-06 3.1E-06 3.4E-06 1.4E-06 3.4E-06 1.4E-06 3.4E-06 3.4E-06

Toluene 3.8E-05 3.8E-05 1.2E-03 1.2E-04 4.5E-05 1.2E-05 4.9E-06 1.2E-04 1.0E-04 9.1E-03 4.9E-06 2.8E-02 5.4E-01 8.6E-04 1.6E+00 1.7E-04 1.9E-03 3.6E-04 2.6E-04 1.7E-02 1.2E-01 4.1E-04 8.6E-02 5.9E-03 8.5E-03 1.2E-05 4.9E-06 1.2E-05 4.9E-06 3.8E-04 1.2E-05

Trichlorofluoromethane (Freon 11) 4.4E-06 5.0E-06 5.0E-06 3.4E-06 1.8E-06 5.0E-06 2.1E-06 4.4E-06 1.8E-06 5.0E-06 2.1E-06 2.8E-06 1.8E-05 5.0E-06 2.1E-05 4.4E-06 4.7E-06 5.0E-06 2.1E-06 1.1E-05 4.7E-06 5.0E-06 5.2E-06 1.1E-05 4.7E-06 5.0E-06 2.1E-06 5.0E-06 2.1E-06 5.0E-06 5.2E-06

1,2,4-Trimethylbenzene 3.4E-04 1.4E-02 3.9E-04 5.0E-04 1.3E-04 3.9E-04 1.5E-04 3.4E-04 1.3E-04 3.9E-04 1.5E-04 3.2E-03 4.3E-02 1.4E-02 4.4E+00 3.4E-04 3.4E-04 1.2E-02 1.8E-03 8.9E-04 3.4E-04 3.4E-02 4.3E-01 8.9E-04 3.4E-04 3.9E-04 1.5E-04 5.7E-03 1.5E-04 1.1E-02 3.8E-04

1,3,5-Trimethylbenzene 6.9E-05 4.1E-04 7.8E-05 2.4E-05 2.7E-05 7.8E-05 3.0E-05 6.9E-05 2.7E-05 7.8E-05 3.0E-05 4.9E-04 9.4E-03 1.3E-03 1.2E+00 6.9E-05 6.9E-05 5.3E-04 4.0E-04 1.8E-04 6.9E-05 3.7E-03 2.3E-01 1.8E-04 6.9E-05 7.8E-05 3.0E-05 7.8E-05 3.0E-05 5.9E-04 7.6E-05

Xylenes 3.0E-05 1.7E-03 7.4E-04 2.1E-04 1.3E-05 3.5E-05 1.4E-05 3.0E-05 1.3E-05 3.5E-05 1.4E-05 2.7E-02 4.7E-01 9.1E-03 7.8E+00 3.0E-05 3.2E-05 2.8E-03 1.9E-03 5.2E-02 8.9E-02 9.9E-03 9.3E-01 1.4E-01 4.0E-03 3.5E-05 1.4E-05 3.0E-05 1.3E-05 2.5E-03 7.4E-04

Cumulative (multi-chemical) 1.5E-03 4.8E-02 8.5E-03 2.2E-03 6.2E-04 1.7E-03 6.6E-04 1.6E-03 6.7E-04 3.2E-02 6.6E-04 7.7E-02 1.6E+00 7.9E-02 3.2E+01 1.6E-03 5.9E-03 2.1E-02 3.4E-02 9.1E-02 4.5E-01 1.2E-01 4.8E+00 1.5E-01 2.9E-02 1.7E-03 6.6E-04 8.0E-03 9.5E-03 2.2E-02 8.1E-03

Notes:






Number of Samples

Number of Detections Average

Maximum Detection

Background Screening Level (1)

No. of Exceed-

ances

Residential Screening Level (2)

No. of Exceed-

ances

Commercial Screening Level (2)

No. of Exceed-

ances

(mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg)

Carcinogenic Polycyclic Aromatic Hydrocarbons (PAHs)

Benzo(a)anthracene 149 94 1.17 24 – – (3) (3) (3) (3)

Benzo(b)fluoranthene 149 73 0.755 12 – – (3) (3) (3) (3)

Benzo(k)fluoranthene 149 57 0.340 9.4 – – (3) (3) (3) (3)

Benzo(a)pyrene 149 82 0.978 16 – – 3.8E-02 c (3) 1.3E-01 c (3)

Chrysene 149 88 0.819 23 – – (3) (3) (3) (3)

Dibenzo(a,h)anthracene 149 34 0.284 11 – – (3) (3) (3) (3)

Indeno(1,2,3-cd)pyrene 149 65 0.346 6.2 – – (3) (3) (3) (3)

Naphthalene 149 43 4.89 320 – – 1.3E+00 e 6 2.8E+00 e 6

Benzo(a)pyrene equivalents 149 NA 1.34 21.0 9.0E-01 29 3.8E-02 c 76 1.3E-01 c 55

Noncarcinogenic PAHs

Acenaphthene 149 21 4.30 630 – – 3.4E+03 r 0 3.3E+04 r 0

Acenaphthylene 149 39 1.39 120 – – 3.4E+03 r 0 3.3E+04 r 0

Anthracene 149 81 1.09 40 – – 1.7E+04 r 0 1.7E+05 r 0

Benzo(g,h,i)perylene 149 62 0.232 3.8 – – 1.7E+03 r 0 1.7E+04 r 0

Fluoranthene 149 102 2.85 84 – – 2.3E+03 r 0 2.2E+04 r 0

Fluorene 149 53 1.24 59 – – 2.3E+03 r 0 2.2E+04 r 0

Phenanthrene 149 95 2.56 87 – – 1.7E+04 r 0 1.7E+05 r 0

Pyrene 149 90 1.09 18 – – 1.7E+03 r 0 1.7E+04 r 0

Metals

Antimony 57 26 1.80 6.3 – – 3.0E+01 c 0 3.8E+02 c 0






Number of Samples


Maximum Detection


No. of Exceed-

ances


No. of Exceed-

ances


No. of Exceed-

ances



Arsenic 90 85 3.38 28 1.0E+01 2 7.0E-02 c 90 2.4E-01 c 90

Barium 57 57 116 495 – – 5.2E+03 c 0 6.3E+04 c 0

Beryllium 57 40 0.355 0.75 – – 1.5E+02 c 0 1.7E+03 c 0

Cadmium 57 57 0.614 1.2 – – 7.0E+01 r 0 8.1E+02 r 0

Chromium (hexavalent) 61 3 2.90 24.8 – – 1.7E+01 c 1 3.7E+01 c 0

Chromium (total) 57 57 52.9 92.3 – – 2.8E+02 r 0 1.4E+03 r 0

Cobalt 57 57 9.55 16.1 – – 6.6E+02 c 0 3.2E+03 c 0

Copper 57 57 15.8 57.4 – – 3.0E+03 c 0 3.8E+04 c 0

Lead 58 45 17.0 360 – – 1.5E+02 c 1 8.0E+02 r 0

Mercury 58 35 0.0728 1 – – 1.8E+01 c 0 1.8E+02 c 0

Molybdenum 57 29 0.392 3.1 – – 3.8E+02 c 0 4.8E+03 c 0

Nickel 57 57 61.2 131 – – 1.6E+03 c 0 1.6E+04 c 0

Selenium 57 3 0.0845 0.42 – – 3.8E+02 c 0 4.8E+03 c 0

Silver 57 46 0.155 0.6 – – 3.8E+02 c 0 4.8E+03 c 0

Thallium 57 4 0.0755 0.21 – – 5.0E+00 c 0 6.3E+01 c 0

Vanadium 57 57 35.7 174 – – 5.3E+02 c 0 6.7E+03 c 0

Zinc 57 57 42.9 187 – – 2.3E+04 c 0 1.0E+05 c 0


TPH-gasoline 111 50 125 5300 – – 5.5E+02 e 4 2.2E+03 e 3

TPH-diesel 111 68 389 14000 – – 5.5E+02 e 14 2.2E+03 e 4

TPH-motor oil 84 41 497 9500 – – 1.8E+03 e 7 1.8E+04 e 0





Number of Samples


Maximum Detection


No. of Exceed-

ances


No. of Exceed-

ances


No. of Exceed-

ances



TPH-recoverable 27 13 71.1 673 – – 1.8E+03 e 0 1.8E+04 e 0

Benzene, Toluene, Ethylbenzene, Xylenes (BTEX), and MTBE

Benzene 102 18 0.125 0.028 – – 1.2E-01 e 6* 2.7E-01 e 2*

Toluene 102 37 0.386 19 – – 5.0E+03 r 0 4.6E+04 r 0

Ethylbenzene 102 13 0.478 28 – – 5.7E+00 r 2 2.9E+01 r 0

Xylenes 102 23 6.46 400 – – 6.0E+02 r 0 2.6E+03 r 0

MTBE 56 0 0.0124 0 – – 3.9E+01 r 0 1.9E+02 r 0

Other Compounds

Ammonia 59 20 26.8 375 – – 1.4E+08 r 0 6.0E+08 r 0

Cyanide 60 9 0.855 14.3 – – 1.6E+03 r 0 2.0E+04 r 0

Sulfide (extractable) 27 1 1.21 3.05 – – 2.8E+06 r 0 1.2E+07 r 0

Total phenols 22 3 2.37 10.9 – – 4.4E+00 c 3 1.3E+01 c 0

Notes:

* All samples in exceedance of the residential and commercial screening levels are nondetect results included in the analysis as one-half the reporting limit.

(1)

(2)

c –

r –

e –

Risk-based screeing levels are:

Cal/EPA California Human Health Screening Level (CHHSL) for soil (Cal/EPA, 2005b)

USEPA Regional Screening Level (RSL) for soil (USEPA, 2008)

Concentrations of benzo(a)pyrene equivalents and arsenic are compared to their associated background levels, as described in the text. Background levels exceed risk-based screening levels for these chemicals.

RWQCB Environmental Screening Level (ESL) for soil based on direct exposure concern (Cal/EPA, 2008).





Number of Samples


Maximum Detection


No. of Exceed-

ances


No. of Exceed-

ances


No. of Exceed-

ances



Notes (continued):

(3)

(4)

(5)

(6)

(7)

(8)

(9)

(10)

(11)

(12)

Cadmium is not considered an oral carcinogen by DTSC Human and Ecological Risk Division (HERD), and therefore the RSL screening level is used instead of the CHHSL screening level to be consistent with HERD.

The carcinogenic toxicity value used by DTSC for benzene is more conservative than the value used by USEPA. Therefore, to be conservative and consistent with Cal/EPA, the benzene ESL is used instead of the RSL as the screening level.

DTSC considers naphthalene carcinogenic by both the oral and inhalation routes, whereas USEPA considers it carcinogenic by inhalation only. Therefore, to be conservative and consistent with Cal/EPA, the naphthalene ESL is used instead of the RSL as the screening level.

Carcinogenic PAHs other than naphthalene are converted to benzo(a)pyrene equivalents for evaluation against the background level for benzo(a)pyrene equivalents and the CHHSL for benzo(a)pyrene. This calculation may be described as follows. On an individual soil sample basis, the reported concentration of each carcinogenic PAH (other than naphthalene) is converted to an equivalent benzo(a)pyrene concentration by multiplying the reported PAH concentration by the toxicity equivalent factor (TEF) for that carcinogenic PAH. The TEF values used in this calculation are those published by DTSC (Cal/EPA, 1994b). The calculated benzo(a)pyrene equivalents are then summed across the nine non-naphthalene carcinogenic PAHs to yield the total benzo(a)pyrene equivalent concentration for the soil sample. The average and maximum benzo(a)pyrene equivalent concentration of 149 soil samples are shown in this table.

Nondetect results are assumed equal to one-half the reporting limit for this analysis.

The CHHSL used for total phenols is that for pentachlorophenol, the most toxic phenol. This is very conservative as the majority of phenols will be significantly less toxic.

The RSL used for acenaphthylene is that of acenaphthene.

The RSL used for phenanthrene is that of anthracene.

The RSL used for sulfide is that of hydrogen sulfide.

The RSL used for benzo(g,h,i)perylene is that of pyrene.


Drafted by: Date: Contract No.:

IRIS ENVIRONMENTAL1438 Webster Street, Suite 302Oakland, California 94612(510) 834-4747

Modeled Soil Lithology and Building Geometry – Slab-on-grade ScenarioFormer Watsonville-1 Manufactured Gas Plant Site

File:

Figure

200-143-C1GSN

SINGLE SOIL LAYER IS DTSC/HERD DEFAULT SOIL

INDOOR AIR

SLAB

SOIL GAS SCREENING LEVELS ARE CALCULATED AT SOIL GAS SAMPLING DEPTH OF 457 cm

OUTDOOR AIR

GROUND SURFACE

NOT TO SCALE

LS = 152 cm

LS = 457 cm

BUILDING WITH SLAB-ON-GRADE

LF = 15 cm (DEFAULT)


Drafted by: Date: Contract No.: File:

Figure

300-143-C1GSN

IRIS ENVIRONMENTAL1438 Webster Street, Suite 302Oakland, California 94612(510) 834-4747

Modeled Soil Lithology and Building Geometry – Basement ScenarioFormer Watsonville-1 Manufactured Gas Plant Site

SINGLE SOIL LAYER IS DTSC/HERD DEFAULT SOIL

INDOOR AIR

SLAB


OUTDOOR AIR

GROUND SURFACE

NOT TO SCALE

BASEMENT

LS = 306 cm

LS = 457 cm

BUILDING WITH BASEMENT

LF = 305 cm (SITE-SPECIFIC)

SOIL GAS SCREENING LEVELS ARE CALCULATED AT SUB-BASEMENT SLAB DEPTH OF 306 cm

Screening-level Vapor Intrusion February 26, 2010 and Soil Data Health Risk Evaluation DRAFT Former Watsonville-1 MGP Site

IRIS ENVIRONMENTAL

APPENDIX A

EXAMPLE JOHNSON AND ETTINGER MODEL REPORT

DATA ENTRY SHEET

DTSCVapor Intrusion GuidanceInterim Final 12/04

ENTER ENTER ENTER (last modified 2/4/09)Soil Soil

Chemical gas OR gasCAS No. conc., conc.,

(numbers only, Cg Cg

no dashes) (μg/m3) (ppmv) Chemical

71432 5.71E+02 Benzene

ENTER ENTER ENTER ENTER ENTERDepth

MORE below grade Soil gas Vadose zone User-definedto bottom sampling Average SCS vadose zone

of enclosed depth soil soil type soil vaporspace floor, below grade, temperature, (used to estimate OR permeability,

LF Ls TS soil vapor kv

(15 or 200 cm) (cm) (oC) permeability) (cm2)

15 152.4 17 1.00E-08

ENTER ENTER ENTER ENTER ENTERMORE Vandose zone Vadose zone Vadose zone Vadose zone Average vapor

SCS soil dry soil total soil water-filled flow rate into bldg.soil type bulk density, porosity, porosity, (Leave blank to calculate)

ρbA nV θw

V Qsoil

(g/cm3) (unitless) (cm3/cm3) (L/m)

1.5 0.43 0.15 5

MOREENTER ENTER ENTER ENTER

Averaging Averagingtime for time for Exposure Exposure

carcinogens, noncarcinogens, duration, frequency,ATC ATNC ED EF(yrs) (yrs) (yrs) (days/yr)

70 30 30 350

END

Soil Gas Concentration Data

SG-SCREENPA Version 2.0; 04/

Reset to Defaults

Lookup Soil Parameters

DTSC / HERDLast Update: 11/1/03

DTSC Indoor Air GuidanceUnclassified Soil Screening Model

Watsonville_Example_Benzene_SG-4-5_Residential_HERD_Soil_Gas_Screening_Model_2009rev2/26/2010

4:33 PM

Example J&E Model Output - Residential Scenario Evaluation of Benzene at SG-4-5

CHEMICAL PROPERTIES SHEET

Henry's Henry's Enthalpy oflaw constant law constant vaporization at Normal Unit

Diffusivity Diffusivity at reference reference the normal boiling Critical risk Reference Molecularin air, in water, temperature, temperature, boiling point, point, temperature, factor, conc., weight,

Da Dw H TR ΔHv,b TB TC URF RfC MW(cm2/s) (cm2/s) (atm-m3/mol) (oC) (cal/mol) (oK) (oK) (μg/m3)-1 (mg/m3) (g/mol)

8.80E-02 9.80E-06 5.54E-03 25 7,342 353.24 562.16 2.9E-05 3.0E-02 78.11

END

2 of 4


INTERMEDIATE CALCULATIONS SHEET

Vadose zone Vadose zone Vadose zone Vadose zone Vadose zone Floor-Source- soil effective soil soil soil wall Bldg.building air-filled total fluid intrinsic relative air effective vapor seam Soil ventilation

separation, porosity, saturation, permeability, permeability, permeability, perimeter, gas rate,LT θa

V Ste ki krg kv Xcrack conc. Qbuilding

(cm) (cm3/cm3) (cm3/cm3) (cm2) (cm2) (cm2) (cm) (μg/m3) (cm3/s)

137.4 0.280 #N/A #N/A #N/A 1.00E-08 4,000 5.71E+02 3.39E+04

Area of Vadoseenclosed Crack- Crack Enthalpy of Henry's law Henry's law Vapor zone

space to-total depth vaporization at constant at constant at viscosity at effective Diffusionbelow area below ave. soil ave. soil ave. soil ave. soil diffusion pathgrade, ratio, grade, temperature, temperature, temperature, temperature, coefficient, length,

AB η Zcrack ΔHv,TS HTS H'TS μTS DeffV Ld

(cm2) (unitless) (cm) (cal/mol) (atm-m3/mol) (unitless) (g/cm-s) (cm2/s) (cm)

1.00E+06 5.00E-03 15 8,050 3.81E-03 1.60E-01 1.78E-04 6.86E-03 137.4

Exponent of InfiniteAverage Crack equivalent source Infinite

Convection Source vapor effective foundation indoor sourcepath vapor Crack flow rate diffusion Area of Peclet attenuation bldg.

length, conc., radius, into bldg., coefficient, crack, number, coefficient, conc.,Lp Csource rcrack Qsoil Dcrack Acrack exp(Pef) α Cbuilding

(cm) (μg/m3) (cm) (cm3/s) (cm2/s) (cm2) (unitless) (unitless) (μg/m3)

15 5.71E+02 1.25 8.33E+01 6.86E-03 5.00E+03 3.50E+10 9.22E-04 5.26E-01

Unitrisk Reference

factor, conc.,URF RfC

(μg/m3)-1 (mg/m3)

2.9E-05 3.0E-02

END

DTSC / HERDLast Update: 11/1/03

DTSC Indoor Air GuidanceUnclassified Soil Screening Model

Watsonville_Example_Benzene_SG-4-5_Residential_HERD_Soil_Gas_Screening_Model_2009rev2/26/2010

4:33 PM


RESULTS SHEET

INCREMENTAL RISK CALCULATIONS:

Incremental Hazardrisk from quotient

vapor from vaporintrusion to intrusion toindoor air, indoor air,carcinogen noncarcinogen(unitless) (unitless)

6.3E-06 1.7E-02

MESSAGE SUMMARY BELOW:

END

Watsonville_Example_Benzene_SG-4-5_Residential_HERD_Soil_Gas_Screening_Model_2009rev 4 of 4


Screening-level Vapor Intrusion February 26, 2010 and Soil Data Health Risk Evaluation DRAFT Former Watsonville-1 MGP Site

IRIS ENVIRONMENTAL

APPENDIX B

SOIL SAMPLING LOCATIONS AND RESULTS

(TGP, 2008a)

Table 2-1Summary of PAH Concentrations in Soil


Sample ID MT-

408-

8-1

DS

S-W

AT1

-1

DS

S-W

AT1

-2

DS

S-W

AT1

-3

DS

S-W

AT1

-4

DS

S-W

AT1

-5

DU

PLI

CA

TED

SS

-WA

T1-5

B-W

AT1

-1-3

.5-5

B-W

AT1

-1-1

0-11

.5

B-W

AT1

-1-1

5-16

.5

Boring ID MT-408-8-1 DSS-WAT1-1 DSS-WAT1-2 DSS-WAT1-3 DSS-WAT1-4 DSS-WAT1-5 DSS-WAT1-5 B-WAT1-1 B-WAT1-1 B-WAT1-1Sample Depth (feet) 0 0 0 0 0 0 0 3.5-5 10-11.5 15-16.5

Sample Date 6/30/1986 6/24/1991 6/24/1991 6/24/1991 6/24/1991 6/24/1991 6/24/1991 6/23/1991 6/23/1991 6/23/1991Laboratory Units McKesson CH2M Hill CH2M Hill CH2M Hill CH2M Hill CH2M Hill CH2M Hill CH2M Hill CH2M Hill CH2M Hill

Naphthalene mg/kg 0.23 ND<0.076 ND<0.74 ND<0.76 ND<0.076 ND<0.72 ND<0.36 ND<0.078 ND<0.079 ND<0.076Acenaphthylene mg/kg 0.14 ND<0.076 ND<0.74 ND<0.76 ND<0.076 ND<0.72 ND<0.36 ND<0.078 ND<0.079 ND<0.076Acenaphthene mg/kg 0.06 ND<0.076 ND<0.74 ND<0.76 ND<0.076 ND<0.72 ND<0.36 ND<0.078 ND<0.079 ND<0.076Fluorene mg/kg 0.04 ND<0.076 ND<0.74 ND<0.76 ND<0.076 ND<0.72 ND<0.36 ND<0.078 ND<0.079 ND<0.076Phenanthrene mg/kg 0.49 ND<0.076 1.3 ND<0.76 ND<0.076 ND<0.72 ND<0.36 ND<0.078 ND<0.079 ND<0.076Anthracene mg/kg 0.13 ND<0.076 ND<0.74 ND<0.76 ND<0.076 ND<0.72 ND<0.36 ND<0.078 ND<0.079 ND<0.076Fluoranthene mg/kg 0.88 0.15 3.2 1.1 0.16 ND<0.72 0.51 ND<0.078 ND<0.079 ND<0.076Pyrene mg/kg 0.77 ND<0.076 ND<0.74 ND<0.76 ND<0.076 ND<0.72 ND<0.36 ND<0.078 ND<0.079 ND<0.076Benzo(g,h,i)perylene mg/kg 0.33 0.16 ND<0.74 ND<0.76 0.16 0.74 ND<0.36 ND<0.078 ND<0.079 ND<0.076Benzo(a)anthracene mg/kg 0.41 ND<0.076 1.4 ND<0.76 0.092 ND<0.72 ND<0.36 ND<0.078 ND<0.079 ND<0.076Benzo(a)pyrene mg/kg 0.4 0.11 2.2 0.95 0.16 ND<0.72 0.46 ND<0.078 ND<0.079 ND<0.076Benzo(b)fluoranthene mg/kg 0.43 0.33 2.6 1.5 0.34 1.3 0.88 ND<0.078 ND<0.079 ND<0.076Benzo(k)fluoranthene mg/kg 0.27 0.08 ND<0.74 ND<0.76 0.077 ND<0.72 ND<0.36 ND<0.078 ND<0.079 ND<0.076Chrysene mg/kg 0.53 ND<0.076 1.4 ND<0.76 ND<0.076 ND<0.72 ND<0.36 ND<0.078 ND<0.079 ND<0.076Dibenzo(a,h)anthracene mg/kg 0.05 0.17 1.4 0.87 0.19 0.75 0.57 ND<0.078 ND<0.079 ND<0.076Indeno(1,2,3-cd)pyrene mg/kg 0.35 0.22 1 0.93 0.21 0.94 0.58 ND<0.078 ND<0.079 ND<0.076Calculated B(a)P Equivalent mg/kg 0.568 0.235 3.227 1.569 0.297 0.915 0.838 0.068 0.069 0.067

Notes:"ND<" = constituent not detected at or above the stated laboratory reporting limit"J" = analyte detected at an estimated concentration between the method detection limit (MDL) and the practical quantitation limit (PQL) "D" = sample diluted to bring the analyte concentration within calibration rangeBold and italicized compounds indicate carcinogenic PAHs used to calculate benzo(a)pyrene equivalent concentration for sample.PAH = polycyclic aromatic hydrocarbonB(a)P = benzo(a)pyrene equivalentSamples analyzed by EPA Method 8310.

Page 1 of 13



Sample IDBoring ID

Sample Depth (feet)Sample Date

Laboratory UnitsNaphthalene mg/kgAcenaphthylene mg/kgAcenaphthene mg/kgFluorene mg/kgPhenanthrene mg/kgAnthracene mg/kgFluoranthene mg/kgPyrene mg/kgBenzo(g,h,i)perylene mg/kgBenzo(a)anthracene mg/kgBenzo(a)pyrene mg/kgBenzo(b)fluoranthene mg/kgBenzo(k)fluoranthene mg/kgChrysene mg/kgDibenzo(a,h)anthracene mg/kgIndeno(1,2,3-cd)pyrene mg/kgCalculated B(a)P Equivalent mg/kg

MW

-WA

T1-1

-3-5

MW

-WA

T1-1

-8-1

0

MW

-WA

T1-1

-12-

13

MW

-WA

T1-1

-18-

19

MW

-WA

T1-1

-20-

21.5

MW

-WA

T1-2

-4-5

MW

-WA

T1-2

-5-6

.5

MW

-WA

T1-2

-10-

11.5

MW

-WA

T1-2

-11.

5-13

MW

-WA

T1-2

-13-

15

MW-WAT1-1 MW-WAT1-1 MW-WAT1-1 MW-WAT1-1 MW-WAT1-1 MW-WAT1-2 MW-WAT1-2 MW-WAT1-2 MW-WAT1-2 MW-WAT1-23.0-5.0 8.0-10.0 12.0-13.0 18.0-19.0 20-21.5 4.0-5.0 5.0-6.5 10-11.5 11.5-13 13-15

6/22/1991 6/22/1991 6/22/1991 6/22/1991 6/22/1991 6/23/1991 6/23/1991 6/23/1991 6/23/1991 6/23/1991CH2M Hill CH2M Hill CH2M Hill CH2M Hill CH2M Hill CH2M Hill CH2M Hill CH2M Hill CH2M Hill CH2M HillND<0.078 ND<0.078 ND<0.077 ND<0.075 ND<0.074 ND<0.78 ND<0.76 ND<0.076 ND<0.076 ND<0.39ND<0.078 ND<0.078 ND<0.077 ND<0.075 ND<0.074 ND<0.78 ND<0.76 ND<0.076 ND<0.076 0.4ND<0.078 ND<0.078 ND<0.077 ND<0.075 ND<0.074 ND<0.78 ND<0.76 ND<0.076 ND<0.076 ND<0.39ND<0.078 ND<0.078 ND<0.077 ND<0.075 ND<0.074 ND<0.78 ND<0.76 ND<0.076 ND<0.076 3.4ND<0.078 ND<0.078 ND<0.077 ND<0.075 ND<0.074 2.2 1.2 ND<0.076 ND<0.076 6.5ND<0.078 ND<0.078 ND<0.077 ND<0.075 ND<0.074 ND<0.78 ND<0.76 ND<0.076 ND<0.076 3.7ND<0.078 ND<0.078 ND<0.077 ND<0.075 ND<0.074 5.9 3.8 ND<0.076 ND<0.076 3.4ND<0.078 ND<0.078 ND<0.077 ND<0.075 ND<0.074 ND<0.78 ND<0.76 ND<0.076 ND<0.076 ND<0.39ND<0.078 ND<0.078 ND<0.077 ND<0.075 ND<0.074 1.4 0.84 ND<0.076 ND<0.076 ND<0.39ND<0.078 ND<0.078 ND<0.077 ND<0.075 ND<0.074 3.4 2.2 ND<0.076 ND<0.076 0.68ND<0.078 ND<0.078 ND<0.077 ND<0.075 ND<0.074 6.7 4.2 ND<0.076 ND<0.076 0.97ND<0.078 ND<0.078 ND<0.077 ND<0.075 ND<0.074 7.6 4.4 ND<0.076 ND<0.076 0.91ND<0.078 ND<0.078 ND<0.077 ND<0.075 ND<0.074 1.5 0.88 ND<0.076 ND<0.076 ND<0.39ND<0.078 ND<0.078 ND<0.077 ND<0.075 ND<0.074 ND<0.78 ND<0.76 ND<0.076 ND<0.076 ND<0.39ND<0.078 ND<0.078 ND<0.077 ND<0.075 ND<0.074 5.1 2.3 ND<0.076 ND<0.076 1ND<0.078 ND<0.078 ND<0.077 ND<0.075 ND<0.074 4.2 2.1 ND<0.076 ND<0.076 ND<0.39

0.068 0.068 0.067 0.066 0.065 10.108 5.944 0.067 0.067 1.510


Page 2 of 13



Sample IDBoring ID



DU

PLI

CA

TEM

W-W

AT1

-2-1

3-15

MW

-WA

T1-2

-15-

16.5

MW

-WA

T1-3

-3.5

-6

MW

-WA

T1-3

-10-

11.5

MW

-WA

T1-3

-13-

15

DU

PLI

CA

TEM

W-W

AT1

-3-1

3-15

MW

-WA

T1-3

-15-

16.5

MW

-WA

T1-3

-18-

20

MW

-WA

T1-3

-20-

21.5

MW

-WA

T1-3

-23-

25

MW-WAT1-2 MW-WAT1-2 MW-WAT1-3 MW-WAT1-3 MW-WAT1-3 MW-WAT1-3 MW-WAT1-3 MW-WAT1-3 MW-WAT1-3 MW-WAT1-313-15 15-16.5 3.5-6 10-11.5 13-15 13-15 15-16.5 18-20 20-21.5 23-25

6/23/1991 6/23/1991 6/24/1991 6/24/1991 6/24/1991 6/24/1991 6/24/1991 6/24/1991 6/24/1991 6/24/1991CH2M Hill CH2M Hill CH2M Hill CH2M Hill CH2M Hill CH2M Hill CH2M Hill CH2M Hill CH2M Hill CH2M Hill

ND<3.8 ND<0.077 ND<0.077 ND<0.79 73 5.8 59 ND<0.76 ND<0.079 ND<0.076ND<3.8 ND<0.077 ND<0.077 ND<0.79 120 8.4 65 ND<0.76 ND<0.079 ND<0.076ND<3.8 ND<0.077 ND<0.077 ND<0.79 630 ND<0.38 ND<3.8 ND<0.76 ND<0.079 ND<0.076

11 ND<0.077 ND<0.077 ND<0.79 ND<3.8 5.1 19 ND<0.76 ND<0.079 ND<0.07627 ND<0.077 ND<0.077 2.6 80 13 54 2 ND<0.079 ND<0.07614 ND<0.077 ND<0.077 0.94 19 5 21 ND<0.76 ND<0.079 ND<0.07615 ND<0.077 ND<0.077 7.8 31 6.4 27 1 ND<0.079 ND<0.076

ND<3.8 ND<0.077 ND<0.077 12 ND<3.8 ND<0.38 ND<3.8 ND<0.76 ND<0.079 ND<0.076ND<3.8 ND<0.077 ND<0.077 ND<0.79 ND<3.8 ND<0.38 ND<3.8 ND<0.76 ND<0.079 ND<0.076

4.8 ND<0.077 ND<0.077 5.4 12 2.3 10 ND<0.76 ND<0.079 ND<0.0766.3 ND<0.077 ND<0.077 8.1 11 2.4 8.4 ND<0.76 ND<0.079 ND<0.0764.7 ND<0.077 ND<0.077 6.7 9.3 1.8 8.4 ND<0.76 ND<0.079 ND<0.076

ND<3.8 ND<0.077 ND<0.077 1.7 ND<3.8 0.5 ND<3.8 ND<0.76 ND<0.079 ND<0.076ND<3.8 ND<0.077 0.079 ND<0.79 ND<3.8 ND<0.38 ND<3.8 ND<0.76 ND<0.079 ND<0.076

7.1 ND<0.077 ND<0.077 7 11 2.3 8.5 ND<0.76 ND<0.079 ND<0.076ND<3.8 ND<0.077 ND<0.077 2 ND<3.8 0.5 ND<3.8 ND<0.76 ND<0.079 ND<0.07610.063 0.067 0.068 12.064 17.269 3.694 13.529 0.665 0.069 0.067


Page 3 of 13



Sample IDBoring ID



MW

-WA

T1-3

-25-

26.5

SS

-WA

T1-1

-1-1

2"

SS

-WA

T1-1

-1-3

0"

SS

-WA

T1-2

-1-1

2"

DU

PLI

CA

TES

S-W

AT1

-2-2

-12"

SS

-WA

T1-2

-1-3

0"

SS

-WA

T1-3

-1-1

2"

SS

-WA

T1-3

-1-3

0"

SS

-WA

T1-4

-1-1

2"

SS

-WA

T1-0

401

MW-WAT1-3 SS-WAT1-1 SS-WAT1-1 SS-WAT1-2 SS-WAT1-2 SS-WAT1-2 SS-WAT1-3 SS-WAT1-3 SS-WAT1-4 SS-WAT1-425-26.5 1 2.5 1 1 2.5 1 2.5 1 2.5

6/24/1991 3/14/2001 3/14/2001 3/14/2001 3/14/2001 3/14/2001 3/14/2001 3/14/2001 3/14/2001 3/26/2001CH2M Hill STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLabND<0.076 ND<0.015 ND<0.015 ND<0.015 ND<0.075 ND<0.015 ND<0.015 ND<0.015 ND<0.015 ND<0.75ND<0.076 ND<0.01 ND<0.01 ND<0.01 ND<0.05 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.5ND<0.076 ND<0.01 ND<0.01 ND<0.01 ND<0.05 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.5ND<0.076 ND<0.005 ND<0.005 ND<0.005 ND<0.025 ND<0.005 ND<0.005 ND<0.005 ND<0.005 2ND<0.076 0.016 ND<0.005 ND<0.005 ND<0.025 ND<0.005 0.052 ND<0.005 0.063 6.4ND<0.076 ND<0.005 ND<0.005 ND<0.005 ND<0.025 ND<0.005 0.011 ND<0.005 0.015 2ND<0.076 0.027 0.0098 ND<0.005 0.063 ND<0.005 0.12 0.016 0.2 15ND<0.076 0.026 0.0064 0.03 0.052 0.0061 0.18 0.015 0.28 16ND<0.076 ND<0.01 ND<0.01 ND<0.01 ND<0.05 ND<0.01 ND<0.01 ND<0.01 0.1 2ND<0.076 0.01 0.0053 0.0094 ND<0.025 ND<0.005 0.047 0.006 0.12 5.8ND<0.076 ND<0.005 ND<0.005 0.01 ND<0.025 ND<0.005 ND<0.005 ND<0.005 0.17 4.5ND<0.076 ND<0.005 ND<0.005 ND<0.005 ND<0.025 ND<0.005 ND<0.005 ND<0.005 0.13 ND<0.25ND<0.076 ND<0.005 ND<0.005 ND<0.005 ND<0.025 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.25ND<0.076 0.012 0.0052 0.01 ND<0.025 ND<0.005 0.035 0.0065 0.1 4.6ND<0.076 ND<0.01 ND<0.01 ND<0.01 ND<0.05 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.5ND<0.076 ND<0.01 ND<0.01 ND<0.01 ND<0.05 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.5

0.067 0.006 0.006 0.014 0.027 0.005 0.010 0.006 0.198 5.261


Page 4 of 13



Sample IDBoring ID



SS

-WA

T1-5

-1-1

2"

SS

-WA

T1-0

501

SS

-WA

T1-6

-1-1

2"

SS

-WA

T1-6

-1-3

0"

SS

-WA

T1-7

-1-1

2"

SS

-WA

T1-7

-1-3

0"

SS

-WA

T1-8

-1-1

2"

SS

-WA

T1-8

-1-3

0"

SS

-WA

T1-9

-1-1

2"

SS

-WA

T1-9

-1-3

0"

SS-WAT1-5 SS-WAT1-5 SS-WAT1-6 SS-WAT1-6 SS-WAT1-7 SS-WAT1-7 SS-WAT1-8 SS-WAT1-8 SS-WAT1-9 SS-WAT1-91 2.5 1 2.5 1 2.5 1 2.5 1 2.5

3/14/2001 3/26/2001 3/14/2001 3/14/2001 3/14/2001 3/14/2001 3/14/2001 3/14/2001 3/14/2001 3/14/2001STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab

ND<0.75 ND<0.015 ND<0.075 ND<0.075 ND<0.015 ND<0.015 ND<0.015 ND<0.075 ND<0.075 ND<0.015ND<0.5 ND<0.01 ND<0.05 ND<0.05 ND<0.01 ND<0.01 ND<0.01 ND<0.05 ND<0.05 ND<0.01ND<0.5 ND<0.01 ND<0.05 ND<0.05 ND<0.01 ND<0.01 ND<0.01 ND<0.05 ND<0.05 ND<0.01ND<0.25 ND<0.005 ND<0.025 ND<0.025 ND<0.005 ND<0.005 ND<0.005 ND<0.025 ND<0.025 ND<0.005

3.3 ND<0.005 1.3 0.66 0.13 0.015 ND<0.005 0.072 ND<0.025 ND<0.0051.5 ND<0.005 0.38 0.12 0.039 ND<0.005 ND<0.005 ND<0.025 ND<0.025 ND<0.00520 0.033 2.9 1.2 0.35 0.034 ND<0.005 0.16 ND<0.025 ND<0.00518 0.016 4.6 2 0.48 0.1 ND<0.005 0.18 ND<0.025 ND<0.0052.5 ND<0.01 ND<0.05 ND<0.05 ND<0.01 ND<0.01 ND<0.01 ND<0.05 ND<0.05 ND<0.0110 0.016 1.5 ND<0.025 ND<0.005 0.032 ND<0.005 0.096 ND<0.025 ND<0.0058.7 0.026 1.7 0.6 ND<0.005 ND<0.005 ND<0.005 0.13 ND<0.025 ND<0.0056.2 ND<0.005 ND<0.025 ND<0.025 ND<0.005 ND<0.005 ND<0.005 ND<0.025 ND<0.025 ND<0.0053.2 ND<0.005 ND<0.025 ND<0.025 ND<0.005 ND<0.005 ND<0.005 ND<0.025 ND<0.025 ND<0.0056.7 0.018 0.83 0.37 ND<0.005 0.028 ND<0.005 0.071 ND<0.025 ND<0.005

ND<0.5 ND<0.01 ND<0.05 ND<0.05 ND<0.01 ND<0.01 ND<0.01 ND<0.05 ND<0.05 ND<0.01ND<0.5 ND<0.01 ND<0.05 ND<0.05 ND<0.01 ND<0.01 ND<0.01 ND<0.05 ND<0.05 ND<0.0110.817 0.030 1.872 0.618 0.005 0.009 0.005 0.154 0.027 0.005


Page 5 of 13



Sample IDBoring ID



B-W

AT1

-2-1

-6.5

B-W

AT1

-2-1

-10

B-W

AT1

-2-1

-15

B-W

AT1

-3-1

-6.5

B-W

AT1

-3-1

-10

DU

PLI

CA

TEB

-WA

T1-3

-2-1

0

B-W

AT1

-3-1

-15

MW

-WA

T1-4

-1-6

.5

MW

-WA

T1-4

-1-1

0

MW

-WA

T1-4

-1-1

5

B-WAT1-2 B-WAT1-2 B-WAT1-2 B-WAT1-3 B-WAT1-3 B-WAT1-3 B-WAT1-3 MW-WAT1-4 MW-WAT1-4 MW-WAT1-46.5 10 15 6.5 10 10 15 6.5 10 15

3/13/2001 3/13/2001 3/13/2001 3/13/2001 3/13/2001 3/13/2001 3/13/2001 3/13/2001 3/13/2001 3/13/2001STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab

ND<0.015 ND<0.015 ND<0.015 ND<0.015 ND<0.015 ND<0.015 ND<0.015 ND<0.015 ND<0.015 ND<0.015ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 0.046 0.01 ND<0.005ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 0.039 0.0072 ND<0.005ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01

ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 0.024 0.0059 ND<0.005ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 0.017 ND<0.005 ND<0.005ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01

0.005 0.005 0.005 0.005 0.005 0.005 0.005 0.008 0.006 0.005


Page 6 of 13



Sample IDBoring ID



MW

-WA

T1-4

-1-2

0

MW

-WA

T1-5

-1-6

.5

MW

-WA

T1-5

-1-1

0

MW

-WA

T1-5

-1-1

5

MW

-WA

T1-5

-1-2

0

DU

PLI

CA

TEM

W-W

AT1

-5-2

-20

HA

1-0-

0.5

HA

1-2.

5-3

HA

1-4-

4.5

HA

2-0-

0.5

MW-WAT1-4 MW-WAT1-5 MW-WAT1-5 MW-WAT1-5 MW-WAT1-5 MW-WAT1-5 HA1 HA1 HA1 HA220 6.5 10 15 20 20 0-0.5 2.5-3 4-4.5 0-0.5

3/13/2001 3/14/2001 3/14/2001 3/14/2001 3/14/2001 3/14/2001 5/10/2004 5/10/2004 5/10/2004 5/10/2004STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab STL ChromaLab Calscience Calscience Calscience Calscience

ND<0.075 ND<0.015 ND<0.015 ND<0.015 ND<0.015 ND<0.015 ND<0.026 ND<0.026 ND<0.026 ND<0.026ND<0.05 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 0.62 ND<0.032 ND<0.032 0.056ND<0.05 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.019 ND<0.019 ND<0.019 ND<0.019

0.3 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 0.041J ND<0.016 ND<0.016 ND<0.016ND<0.025 0.071 ND<0.005 ND<0.005 ND<0.005 ND<0.005 0.44 0.0051J 0.0042J 0.094

0.86 0.025 ND<0.005 ND<0.005 ND<0.005 ND<0.005 0.12 ND<0.0019 ND<0.0019 0.0032J2.5 0.32 ND<0.005 ND<0.005 ND<0.005 ND<0.005 1.2 0.007J ND<0.0049 0.33

0.81 0.51 ND<0.005 ND<0.005 ND<0.005 ND<0.005 0.15 0.0082J ND<0.0031 0.14ND<0.05 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 0.053 ND<0.0047 ND<0.0047 0.11

0.62 0.2 ND<0.005 ND<0.005 ND<0.005 ND<0.005 0.68 0.003J ND<0.0029 0.190.51 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 0.46 0.0049J ND<0.0032 0.16

ND<0.025 0.13 ND<0.005 ND<0.005 ND<0.005 ND<0.005 0.34 ND<0.0035 ND<0.0035 0.15ND<0.025 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005 0.19 ND<0.0022 ND<0.0022 0.06

0.37 0.15 ND<0.005 ND<0.005 ND<0.005 ND<0.005 0.11 0.003J ND<0.0026 0.18ND<0.05 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.0044 ND<0.0044 ND<0.0044 ND<0.0044ND<0.05 ND<0.01 ND<0.01 ND<0.01 ND<0.01 ND<0.01 0.27 0.024J ND<0.0025 0.079

0.589 0.039 0.005 0.005 0.005 0.005 0.610 0.009 0.003 0.210


Page 7 of 13



Sample IDBoring ID



DU

P 2

HA

2-1-

1.5

HA

2-2.

5-3

HA

2-4-

4.5

HA

3-0-

0.5

HA

3-1-

1.5

HA

3-2.

5-3

HA

3-4-

4.5

HA

4-0-

0.5

HA

4-2.

5-3

HA2 HA2 HA2 HA2 HA3 HA3 HA3 HA3 HA4 HA40-0.5 1-1.5 2.5-3 4-4.5 0-0.5 1-1.5 2.5-3 4-4.5 0-0.5 2.5-3

5/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience CalscienceND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026

0.45 0.034J ND<0.032 ND<0.032 0.32 ND<0.032 0.12 ND<0.032 ND<0.032 ND<0.032ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019

0.082 ND<0.016 ND<0.016 ND<0.016 0.07 0.041J 0.024J ND<0.016 ND<0.016 ND<0.0160.57 0.0046J ND<0.0022 ND<0.0022 0.96 0.55 0.09 ND<0.0022 0.027J 0.012J0.23 ND<0.0019 ND<0.0019 ND<0.0019 0.38 0.16 0.027J ND<0.0019 0.0051J 0.0044J2.4D 0.011J ND<0.0049 ND<0.0049 3.6D 1.6 0.22 ND<0.0049 0.16 0.0092J0.94 ND<0.0031 0.062J ND<0.0031 1.6D 0.58 0.095 ND<0.0031 ND<0.0031 0.011J0.29 ND<0.0047 ND<0.0047 ND<0.0047 0.48 0.33 0.07 ND<0.0047 0.33 ND<0.00471.3D 0.0032J ND<0.0029 ND<0.0029 2.5D 0.88 0.11 ND<0.0029 0.051 ND<0.00290.97 0.0062J ND<0.0032 ND<0.0032 2.0D 0.87 0.13 ND<0.0032 0.19 ND<0.00320.69 ND<0.0035 ND<0.0035 ND<0.0035 1.7D 0.49 0.12 ND<0.0035 0.13 ND<0.00350.39 ND<0.0022 ND<0.0022 ND<0.0022 0.61 0.45 0.061 ND<0.0022 0.15 ND<0.00221.2D 0.0055J 0.0027J ND<0.0026 2.3D 0.82 0.14 ND<0.0026 0.06 ND<0.0026

ND<0.0044 0.0087J ND<0.0044 ND<0.0044 ND<0.0044 0.035J ND<0.0044 ND<0.0044 ND<0.0044 ND<0.00440.51 0.0037J 0.0075J ND<0.0025 0.85 0.45 0.098 ND<0.0025 0.089 ND<0.00251.272 0.010 0.004 0.003 2.590 1.117 0.171 0.003 0.233 0.003


Page 8 of 13



Sample IDBoring ID



HA

4-4-

4.5

HA

5-0-

0.5

HA

5-2.

5-3

HA

5-4-

4.5

HA

6-0-

0.5

HA

6-1-

1.5

HA

6-2.

5-3

HA

6-3-

3.5

HA

6-4-

4.5

HA

7-0-

0.5

HA4 HA5 HA5 HA5 HA6 HA6 HA6 HA6 HA6 HA74-4.5 0-0.5 2.5-3 4-4.5 0 - 0.5 1-1.5 2.5-3 3-3.5 4-4.5 0-0.5

5/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience

0.026J ND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.260ND<0.032 0.041J ND<0.032 ND<0.032 0.034J ND<0.032 ND<0.032 ND<0.032 ND<0.032 ND<0.320ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.190ND<0.016 ND<0.016 ND<0.016 ND<0.016 0.021J ND<0.016 ND<0.016 ND<0.016 ND<0.016 ND<0.160ND<0.0022 0.057 ND<0.0022 ND<0.0022 0.29 0.079 ND<0.0022 0.0039J ND<0.0022 0.140JND<0.0019 0.017J ND<0.0019 ND<0.0019 0.069 0.023J ND<0.0019 ND<0.0019 ND<0.0019 0.033JND<0.0049 0.14 ND<0.0049 ND<0.0049 0.7 0.26 0.0067J 0.0087J ND<0.0049 0.47JND<0.0031 0.082 ND<0.0031 ND<0.0031 0.4 0.1 ND<0.0031 ND<0.0031 ND<0.0031 1.9ND<0.0047 0.043J ND<0.0047 ND<0.0047 0.35 0.076 0.0089J ND<0.0047 ND<0.0047 0.92ND<0.0029 0.091 ND<0.0029 ND<0.0029 0.29 0.17 0.0034J 0.0029J ND<0.0029 0.210JND<0.0032 0.13 ND<0.0032 ND<0.0032 0.54 0.17 0.0097J 0.0067J ND<0.0032 0.89ND<0.0035 0.081 ND<0.0035 ND<0.0035 0.49 0.15 0.0054J ND<0.0035 ND<0.0035 0.6ND<0.0022 0.055 ND<0.0022 ND<0.0022 0.2 0.064 0.0033J 0.0028J ND<0.0022 0.220JND<0.0026 0.082 ND<0.0026 ND<0.0026 0.41 0.18 0.0034J 0.0039J ND<0.0026 0.290JND<0.0044 ND<0.0044 ND<0.0044 ND<0.0044 0.36 0.065 ND<0.0044 ND<0.0044 ND<0.0044 0.480JND<0.0025 0.091 ND<0.0025 ND<0.0025 0.19 0.1 0.029J ND<0.0025 ND<0.0025 0.77

0.003 0.163 0.003 0.003 0.784 0.242 0.015 0.008 0.003 1.236


Page 9 of 13



Sample IDBoring ID



DU

P 1

HA

7-1-

1.5

HA

7-2.

5-3

HA

7-4-

4.5

HA

8-0-

0.5

HA

8-1.

5-2

HA

8-2.

5-3

HA

8-4-

4.5

HA

10-0

-0.5

HA

10-1

.5-2

HA7 HA7 HA7 HA7 HA8 HA8 HA8 HA8 HA10 HA100-0.5 1-1.5 2.5-3 4-4.5 0-0.5 1.5-2 2.5-3 4-4.5 0-0.5 1.5-2

5/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004 5/10/2004Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience CalscienceND<0.026 ND<0.026 0.027J ND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026 0.25ND<0.032 ND<0.032 ND<0.032 ND<0.032 ND<0.032 0.32 ND<0.032 ND<0.032 ND<0.032 ND<0.032ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019ND<0.016 ND<0.016 ND<0.016 ND<0.016 ND<0.016 0.031J ND<0.016 ND<0.016 ND<0.016 0.023J

0.11 0.0023J ND<0.0022 ND<0.0022 0.032J 0.24 ND<0.0022 0.008J 0.087 0.130.025J ND<0.0019 ND<0.0019 ND<0.0019 0.0069J 0.096 ND<0.0019 0.0021J 0.018J 0.029J0.48 0.0092J ND<0.0049 ND<0.0049 0.12 0.62 ND<0.0049 0.039J 0.23 0.20.22 0.0044J ND<0.0031 ND<0.0031 0.053 0.29 ND<0.0031 0.022J 0.13 0.0630.42 0.0089J ND<0.0047 ND<0.0047 0.087 0.21 ND<0.0047 ND<0.0047 0.45 0.039J0.14 ND<0.0029 ND<0.0029 ND<0.0029 0.042J 0.53 ND<0.0029 0.038J 0.11 0.0710.4 0.0099J ND<0.0032 ND<0.0032 0.092 0.63 ND<0.0032 0.024J 0.25 0.062

0.33 0.0036J ND<0.0035 ND<0.0035 0.086 0.48 ND<0.0035 0.012J 0.22 0.0530.12 0.0024J ND<0.0022 ND<0.0022 0.036J 0.2 ND<0.0022 0.013J 0.17 0.020J0.19 0.0041J ND<0.0026 ND<0.0026 0.053 0.57 ND<0.0026 0.042J 0.16 0.064

ND<0.0044 0.0055J ND<0.0044 ND<0.0044 ND<0.0044 0.17 ND<0.0044 ND<0.0044 ND<0.0044 0.016J0.36 0.0077J ND<0.0025 ND<0.0025 0.085 0.45 ND<0.0025 0.014J 0.14 0.049J0.498 0.013 0.003 0.003 0.118 0.860 0.003 0.033 0.316 0.087


Page 10 of 13



Sample IDBoring ID



HA

10-2

.5-3

GP

1-0.

5-1

GP

1-2.

5-3

GP

1-5-

5.5

GP

1-10

-10.

5

GP

1-15

-15.

5

GP

1-20

-20.

5

DU

P 4

GP

1-24

-24.

5

GP

2-0.

5-1

HA10 GP1 GP1 GP1 GP1 GP1 GP1 GP1 GP1 GP22.5-3 0.5-1 2.5-3 5-5.5 10-10.5 15-15.5 20-20.5 20-20.5 24-24.5 0.5-1

5/10/2004 5/11/2004 5/11/2004 5/11/2004 5/11/2004 5/11/2004 5/11/2004 5/11/2004 5/11/2004 5/11/2004Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience CalscienceND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026 250D 9.8 0.25 0.33 ND<0.026ND<0.032 ND<0.032 ND<0.032 ND<0.032 ND<0.032 ND<0.640 ND<0.032 ND<0.032 ND<0.032 ND<0.032ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.380 ND<0.019 ND<0.019 ND<0.019 ND<0.019ND<0.016 0.77 0.13 0.086 0.033J 59D 2.3D 0.038J 0.035J 0.140.0086J 7.6D 0.11 0.076 0.12 67D 3.2D 0.030J 0.010J 1.3D0.0024J 2.2DJ 0.078 0.024J 0.062 36D 1.6D 0.0086J 0.0022J 0.520.020J 39D 1.4 0.46 0.58 73D 3.7D 0.007J ND<0.0049 5.6D0.015J 15D 2.3D 0.25 0.54 17 0.68 0.0066J 0.0072J 3.0D0.012J 1.9 0.37 0.1 ND<0.0047 1.9 0.17 ND<0.0047 ND<0.0047 1.3D

0.0072J 23D 1.7D 0.2 0.42 21D 0.84 ND<0.0029 ND<0.0029 3.5D0.014J 13D 1.3D 0.049J 0.35 16 0.58 ND<0.0032 ND<0.0032 3.6D

0.0064J 5.0D 0.56 ND<0.0035 0.24 12 0.42 ND<0.0035 ND<0.0035 2.8D0.0034J 6.2D 0.29 ND<0.0022 0.1 9.4 0.25 ND<0.0022 ND<0.0022 1.5D0.0097J 23D 1.6D 0.28 0.37 16DJ 0.76 ND<0.0026 ND<0.0026 3.5D

ND<0.0044 ND<0.0044 ND<0.0044 ND<0.0044 ND<0.0044 ND<0.088 ND<0.0044 ND<0.0044 ND<0.0044 ND<0.00440.0075J 5.1D 0.22 ND<0.0025 ND<0.0025 6.2 0.095 ND<0.0025 ND<0.0025 2.1D

0.017 17.161 1.594 0.073 0.431 21.035 0.749 0.003 0.003 4.626


Page 11 of 13



Sample IDBoring ID



GP

2-2.

5-3

GP

2-5-

5.5

DU

P 5

GP

2-10

-10.

5

GP

2-15

-15.

5

GP

3-0.

5-1

GP

3-2.

5-3

GP

3-5-

5.5

GP

3-10

-10.

5

GP

3-15

-15.

5

GP2 GP2 GP2 GP2 GP2 GP3 GP3 GP3 GP3 GP32.5-3 5-5.5 5-5.5 10-10.5 15-15.5 0.5-1 2.5-3 5-5.5 10-10.5 15-15.5

5/11/2004 5/11/2004 5/11/2004 5/11/2004 5/11/2004 5/11/2004 5/11/2004 5/11/2004 5/11/2004 5/11/2004Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience CalscienceND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026 ND<0.026ND<0.032 ND<0.032 ND<0.032 ND<0.032 ND<0.032 ND<0.032 ND<0.032 ND<0.032 ND<0.032 ND<0.032ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019

0.21 ND<0.016 0.037J ND<0.016 5.9D 0.020J ND<0.016 ND<0.016 ND<0.016 ND<0.0163.6D 0.11 0.25 0.0074J 7.1D 0.067 0.0036J ND<0.0022 ND<0.0022 0.0023J0.68 0.019J 0.064 0.0029J 4.5D 0.017J ND<0.0019 ND<0.0019 ND<0.0019 0.012J8.5D 0.22 0.76 ND<0.0049 12D 0.16 0.0053J ND<0.0049 ND<0.0049 0.017J4.7D 0.17 0.73 ND<0.0031 0.57 0.069 ND<0.0031 ND<0.0031 ND<0.0031 ND<0.00313.8D ND<0.0047 0.88 ND<0.0047 0.18 0.044J ND<0.0047 ND<0.0047 ND<0.0047 ND<0.00473.6D 0.13 0.53 ND<0.0029 2.9D 0.11 0.0033J ND<0.0029 ND<0.0029 ND<0.00295.1D 0.23 0.95 ND<0.0032 1.1D 0.13 ND<0.0032 ND<0.0032 ND<0.0032 ND<0.00323.7D 0.1 0.58 ND<0.0035 1 0.08 ND<0.0035 ND<0.0035 ND<0.0035 ND<0.00351.6D 0.018J 0.15 ND<0.0022 0.43 0.030J ND<0.0022 ND<0.0022 ND<0.0022 ND<0.00223.8D 0.11 0.52 ND<0.0026 2.2D 0.095 ND<0.0026 ND<0.0026 ND<0.0026 ND<0.0026

ND<0.0044 ND<0.0044 ND<0.0044 ND<0.0044 ND<0.0044 ND<0.0044 ND<0.0044 ND<0.0044 ND<0.0044 ND<0.00443.8D ND<0.0025 0.56 ND<0.0025 0.15 0.039J 0.003J ND<0.0025 ND<0.0025 ND<0.00256.409 0.257 1.138 0.003 1.571 0.158 0.003 0.003 0.003 0.003


Page 12 of 13



Sample IDBoring ID



GP

3-20

-20.

5

GP

3-23

.5-2

4

GP

4-0.

5-1

GP

4-2.

5-3

GP

4-5-

5.5

GP

4-10

-10.

5

GP

4-15

-15.

5

GP

4-20

-20.

5

GP

4-23

.5-2

4

GP3 GP3 GP4 GP4 GP4 GP4 GP4 GP4 GP420-20.5 23.5-24 0.5-1 2.5-3 5-5.5 10-10.5 15-15.5 20-20.5 23.5-24

5/11/2004 5/11/2004 5/11/2004 5/11/2004 5/11/2004 5/11/2004 5/11/2004 5/11/2004 5/11/2004Calscience Calscience Calscience Calscience Calscience Calscience Calscience Calscience CalscienceND<0.026 ND<0.026 ND<0.026 ND<0.026 0.16 ND<0.026 320D 0.084 0.16

8.6 ND<0.032 ND<0.032 ND<0.032 ND<0.032 ND<0.032 ND<0.320 ND<0.032 ND<0.032ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.019 ND<0.190 ND<0.019 ND<0.019

18D 0.072 0.13 0.13 0.091 0.13 58D 0.021J ND<0.01619D 0.016J 0.16 0.14 0.84 0.71 87D 0.031J 0.0052J14D 0.055 0.06 0.17 0.48 0.45 40D 0.014J ND<0.001929D 0.066 1 2.8D 6.6D 3.9D 84D 0.018J ND<0.00497.8D 0.017J 0.84 1.3D 3.3D 2.6D 18D 0.011J 0.0033J0.85 ND<0.0047 0.38 0.34 0.42 0.5 1.2 ND<0.0047 ND<0.00479.0D 0.0061D 0.91 1.6D 3.5D 2.6D 24D ND<0.0029 ND<0.00295.5D 0.004J 0.62 0.76 3.0D 2.8D 14D ND<0.0032 ND<0.00324.4D ND<0.0035 0.47 0.49 1.7 1.8 7.8 ND<0.0035 ND<0.00352.7D ND<0.0022 0.31 0.32 0.99 0.85 6 ND<0.0022 ND<0.00226.9D ND<0.0026 0.85 1.1D 3.2D 2.4D 19D ND<0.0026 ND<0.0026

ND<0.0044 ND<0.0044 ND<0.0044 ND<0.0044 ND<0.0044 ND<0.0044 ND<0.044 ND<0.0044 ND<0.00442.0D ND<0.0025 0.22 0.19 1.2D 0.67 5.2 ND<0.0025 ND<0.00257.380 0.006 0.820 1.032 3.772 3.417 18.497 0.003 0.003


Page 13 of 13

Table 2-2Summary of Metals Concentrations in Soil


Ant

imon

y

Ars

enic

Bar

ium

Ber

ylliu

m

Cad

miu

m

Chr

omiu

m(H

exav

alen

t)

Chr

omiu

m(to

tal)

Cob

alt

Cop

per

Lead

Mer

cury

Mol

ybde

num

Nic

kel

Sel

eniu

m

Silv

er

Thal

lium

Van

adiu

m

Zinc

mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kgEPA

Method 60107060 or6010B1 6010 6010 6010

7196/7196A or 71992 6010 6010 6010 6010 7471 6010 6010 7740 6010 7841 6010 6010

YearMT-408-8-1 0 1986 NA 28* NA NA NA NA NA NA NA 360* 1* NA NA NA NA NA NA NA

DSS-WAT1-1 0 1991 2.6 0.84 36.7 ND<0.2 0.3 ND<11.4 48.7 6.7 13.6 ND<4.1 0.22 ND<0.5 30.2 ND<0.18 ND<0.2 ND<0.21 24.3 28.7

DSS-WAT1-2 0 1991 3.7 8.79 146 ND<0.2 0.7 ND<11.1 43.5 9.6 30.4 83.3 0.11 ND<0.4 51.9 ND<0.18 ND<0.2 ND<0.2 35.8 118

DSS-WAT1-3 0 1991 3.2 10.3 88.9 0.2 1.2 24.8 28 7.7 38.7 106 0.2 0.5 28 ND<0.18 ND<0.2 ND<0.2 27.3 138

DSS-WAT1-4 0 1991 4.4 2.15 55.3 ND<0.2 0.5 ND<12.1 74.4 10 16.8 26.4 ND<0.07 ND<0.5 47.5 ND<0.19 ND<0.2 ND<0.22 37.1 55.1

DSS-WAT1-5 0 1991 ND<1.7 4.63 95.5 ND<0.2 0.9 ND<10.7 31 8 21.8 44.9 0.06 ND<0.4 32.8 0.2 ND<0.2 ND<0.19 30.9 187

DSS-WAT1-5 0 DUP 1991 5.9 5.33 129 0.3 1.1 ND<10.8 50.3 9.3 32.7 154 0.13 ND<0.4 37.4 ND<0.17 ND<0.2 ND<0.19 43.3 164

B-WAT1-1 3.5 1991 2.5 2.79 114 0.5 0.7 ND<11.6 44.2 16.1 16 5.4 ND<0.07 ND<0.5 36 ND<0.19 0.4 ND<0.21 45.8 42.5

10 2.9 1.67 72.4 ND<0.2 0.5 ND<11.7 63.2 12.4 9.5 ND<4.2 ND<0.07 ND<0.5 63.2 ND<0.19 0.4 ND<0.21 27 30.7

15 4.1 2.91 114 ND<0.2 0.7 ND<11.4 56.2 14.5 17.9 ND<4.1 ND<0.07 ND<0.5 120 ND<0.18 0.3 ND<0.2 34.2 36.5

MW-WAT1-1 3 1991 2.9 2.84 150 0.6 0.6 ND<11.6 40.6 11.9 16.9 7.1 ND<0.07 0.9 33.3 ND<0.19 ND<0.2 ND<0.21 55.5 40.3

8 5.9 2.69 129 0.5 0.5 ND<11.7 45.1 13 14.5 6.7 ND<0.07 ND<0.5 31.3 ND<0.19 ND<0.2 0.21 53.6 36.4

12 3.3 2.12 140 0.2 0.3 ND<11.5 66.1 13.5 14.7 ND<4.1 ND<0.07 ND<0.5 87.7 ND<0.18 ND<0.2 0.21 31.4 35.7

18 2.3 2.52 83.7 ND<0.2 0.3 ND<11.3 66.6 9.7 12.8 ND<4.1 ND<0.07 ND<0.5 69 ND<0.18 ND<0.2 ND<0.2 24.2 25.5

20 5.5 1.94 495 ND<0.2 0.5 ND<11.1 52.4 10.6 23.9 4.3 ND<0.07 ND<0.4 79.7 ND<0.18 ND<0.2 ND<0.2 39.5 48.4

MW-WAT1-2 4 1991 3.9 4.77 165 ND<0.2 0.9 ND<11.6 34 11.5 17.5 51.7 0.07 ND<0.5 131 ND<0.19 0.3 ND<0.21 174 62.7

5 6.3 3.14 175 0.4 0.8 ND<11.4 63.9 12.6 19.7 41.9 ND<0.07 ND<0.5 67.9 ND<0.18 0.4 ND<0.21 53.1 53.8

10 3.5 2.25 86.8 0.3 0.9 ND<11.4 82.6 10 12.9 5.2 ND<0.07 ND<0.5 63.5 ND<0.18 0.5 ND<0.2 41 32.4

11.5 4.3 3.05 104 0.4 0.6 ND<11.4 82.4 11 16.9 ND<4.1 ND<0.07 ND<0.5 54.1 ND<0.18 0.2 ND<0.21 37.9 36.9

13 5.4 1.61 77.4 0.2 0.9 ND<11.7 92 11.4 12.2 5.2 ND<0.07 ND<0.5 82 ND<0.19 0.4 ND<0.21 40 34

13 DUP 3.5 1.42 63.7 ND<0.2 0.5 ND<11.4 66.6 9.5 11.7 ND<4.1 ND<0.07 ND<0.5 69.1 ND<0.18 ND<0.2 ND<0.21 33.4 28.6

15 4 1.94 198 ND<0.2 0.6 ND<11.5 64.5 11.5 57.4 5 ND<0.07 ND<0.5 89.7 ND<0.18 ND<0.2 ND<0.21 28.6 55.3

MW-WAT1-3 3.5 1991 2.6 2.26 156 0.3 0.8 ND<11.6 33.2 14.3 15.7 7 ND<0.07 ND<0.5 27.7 ND<0.18 0.3 ND<0.21 45.4 44.2

10 3.3 2.81 141 ND<0.2 0.6 ND<11.8 58.1 10.6 21.4 ND<4.3 0.08 0.7 72.9 ND<0.19 0.5 ND<0.21 31.1 46.2

13 5.1 1.44 151 ND<0.2 0.8 ND<10.9 67.7 15.6 17.2 ND<4 ND<0.07 ND<0.4 119 ND<0.18 0.5 ND<0.2 41.2 40.4

13 DUP ND<1.8 1.75 97.9 ND<0.2 0.6 ND<12.7 66.9 10.6 12.5 ND<4.1 ND<0.07 ND<0.5 93.7 ND<0.18 0.3 ND<0.21 26 31.4

15 3.5 1.33 93.7 ND<0.2 0.6 ND<11.3 75 9.9 14 ND<4.1 ND<0.07 ND<0.5 83.4 ND<0.18 0.6 ND<0.2 28.2 31.5

18 4 1.71 70 ND<0.2 0.5 ND<11.3 55.3 8.7 8.8 ND<4.1 ND<0.07 ND<0.5 63.2 ND<0.18 0.4 ND<0.2 21.6 25.4

20 2.4 3.74 57.6 ND<0.2 0.5 ND<11.6 37.9 5.3 6.9 ND<4.2 ND<0.07 ND<0.5 50.4 ND<0.19 0.3 ND<0.21 18.4 21.2

23 4.8 2.01 115 ND<0.2 0.5 ND<11.3 92.3 9.5 12.1 ND<4.1 ND<0.07 ND<0.5 86 ND<0.18 0.4 ND<0.2 27.1 29

25 4.6 2.14 91.6 ND<0.2 0.6 ND<11.4 74.6 10.6 13.6 ND<4.1 ND<0.07 ND<0.5 82.9 ND<0.18 0.3 ND<0.21 29.3 32.5

SS-WAT1-1 1 2001 NA 2.7 NA NA NA ND<0.2 NA NA NA NA NA NA NA NA NA NA NA NA


SS-WAT1-2 1 2001 NA 10 NA NA NA ND<0.2 NA NA NA NA NA NA NA NA NA NA NA NA

1 DUP NA 5.7 NA NA NA ND<0.2 NA NA NA NA NA NA NA NA NA NA NA NA


Boring/SamleID

SampleDepth(feet)

Page 1 of 2

Table 2-2Summary of Metals Concentrations in Soil


Ant

imon

y

Ars

enic

Bar

ium

Ber

ylliu

m

Cad

miu

m

Chr

omiu

m(H

exav

alen

t)

Chr

omiu

m(to

tal)

Cob

alt

Cop

per

Lead

Mer

cury

Mol

ybde

num

Nic

kel

Sel

eniu

m

Silv

er

Thal

lium

Van

adiu

m

Zinc

mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kg mg/kgEPA

Method 60107060 or6010B1 6010 6010 6010

7196/7196A or 71992 6010 6010 6010 6010 7471 6010 6010 7740 6010 7841 6010 6010

Boring/SamleSampleDepth















B-WAT1-2 6.5 2001 NA ND<1 NA NA NA ND<0.2 NA NA NA NA NA NA NA NA NA NA NA NA

10 NA ND<1 NA NA NA ND<0.2 NA NA NA NA NA NA NA NA NA NA NA NA


B-WAT1-3 6.5 2001 NA ND<1 NA NA NA ND<0.2 NA NA NA NA NA NA NA NA NA NA NA NA



15 NA 1.6 NA NA NA ND<0.2 NA NA NA NA NA NA NA NA NA NA NA NA

MW-WAT1-4 6.5 2001 NA 1.4 NA NA NA ND<0.2 NA NA NA NA NA NA NA NA NA NA NA NA




MW-WAT1-5 6.5 2001 NA 3.4 NA NA NA ND<0.2 NA NA NA NA NA NA NA NA NA NA NA NA





HA9 0-0.5 2004 NA NA NA NA NA 0.22 NA NA NA NA NA NA NA NA NA NA NA NA

0-0.5 DUP NA NA NA NA NA 0.17 NA NA NA NA NA NA NA NA NA NA NA NA

1-1..5 NA NA NA NA NA 0.26 NA NA NA NA NA NA NA NA NA NA NA NA

Notes: mg/kg = milligrams per kilogram 1 Arsenic samples collected in 1991 were analyzed by EPA Method 7060; arsenic samples collected in 2001 were analyzed by EPA Method 6010B. "ND<" = consitituent not detected at or above the stated laboratory reporting limit 2 Cr6 samples collected in 1991 were analyzed by EPA Method 7196; Cr6 samples collected in 2001 were analyzed by EPA Method 7196A; NA = not analyzed Cr6 samples collected in 2004 were analyzed by EPA Method 7199.

* unknown analytical method

Page 2 of 2

Table 2-3Summary of TPH and TRPH Concentrations in Soil


TPHg TPHd TPHmo(mg/kg) (mg/kg) (mg/kg) (mg/kg)

DSS-1-WAT1-1 0 (surface soil) 1991 1.5 ND<110 NA 84.9DSS-1-WAT1-2 0 (surface soil) 1991 8.1 ND<110 NA 35.6DSS-1-WAT1-3 0 (surface soil) 1991 1.9 ND<110 NA 66.5DSS-1-WAT1-4 0 (surface soil) 1991 ND<1.2 ND<24 NA 38.6DSS-1-WAT1-5 0 (surface soil) 1991 2.2 ND<110 NA 91.2B-WAT1-1 3.5 1991 2.7 ND<12 NA ND<1.9

10 ND<1.2 ND<12 NA ND<1.915 ND<1.1 ND<11 NA ND<1.9

MW-WAT1-1 3 1991 ND<1.2 ND<12 NA ND<1.98 ND<1.2 ND<12 NA ND<1.6

12 ND<1.2 ND<12 NA ND<1.918 ND<1.1 ND<11 NA ND<1.620 ND<1.1 ND<11 NA ND<1.8

MW-WAT1-2 4 1991 5.8 ND<120 NA 1415 3.8 ND<110 NA 124

10 ND<1.1 ND<11 NA ND<1.911.5 ND<1.1 ND<11 NA 2.513 21 600 NA 19.4

13-DUP 200 1,200 NA 27.115 1.9 ND<12 NA ND<1.9

MW-WAT1-3 3.5 1991 ND<1.2 ND<12 NA ND<1.910 21 ND<120 NA 18.813 3,000 4,400 NA 67315 3,500 2,500 NA 31618 120 210 NA 29620 1.6 ND<12 NA ND<1.923 1.7 ND<11 NA ND<1.925 ND<1.1 ND<11 NA ND<1.9


SS-WAT1-2 1 2001 ND<1 12 80 NA2.5 ND<1 7.9 71 NA

SS-WAT1-3 1 2001 ND<1 15 140 NA2.5 ND<1 9.1 120 NA

SS-WAT1-4 1 2001 ND<1 36 150 NA2.5 ND<1 750 660 NA

SS-WAT1-5 1 2001 ND<1 860 2,000 NA2.5 ND<1 2.3 ND<50 NA

SS-WAT1-6 1 2001 ND<1 700 1,500 NA2.5 ND<1 270 530 NA

SS-WAT1-7 1 2001 ND<1 50 400 NA2.5 ND<1 6.4 ND<50 NA

SS-WAT1-8 1 2001 ND<1 210 2,300 NA2.5 ND<1 4.8 55 NA


B-WAT1-2 6.5 2001 ND<1 ND<1 ND<50 NA10 ND<1 ND<1 ND<50 NA15 ND<1 ND<1 ND<50 NA

TRPHBoring/SampleNumber

Total Petroleum HydrocarbonsDate SampledSample Depth

(feet bgs)

Page 1 of 2

Table 2-3Summary of TPH and TRPH Concentrations in Soil


TPHg TPHd TPHmo(mg/kg) (mg/kg) (mg/kg) (mg/kg)

TRPHBoring/SampleNumber

Total Petroleum HydrocarbonsDate SampledSample Depth

(feet bgs)

B-WAT1-3 6.5 2001 ND<1 1.5 ND<50 NA10 ND<1 1.3 ND<50 NA15 ND<1 ND<1 ND<50 NA

MW-WAT1-4 6.5 2001 ND<1 ND<1 ND<50 NA10 ND<1 ND<1 ND<50 NA15 ND<1 ND<1 ND<50 NA20 ND<1 350 450 NA

MW-WAT1-5 6.5 2001 ND<1 47 ND<50 NA10 ND<1 ND<1 ND<50 NA15 ND<1 ND<1 ND<50 NA20 ND<1 ND<1 ND<50 NA

GP1 2.5-3 2004 ND<0.22 2,100 4,200 NA5-5.5 ND<0.20 66 120 NA

10-10.5 490 400 1500 NA15-15.5 5,300 14,000 9,500 NA20-20.5 1 1,500 2,500 NA

20-20.5 DUP 0.53 ND<5.0 ND<25 NA24-24.5 ND<0.69 ND<5.0 ND<25 NA

GP2 2.5-3 2004 ND<0.50 98 2,700 NA5-5.5 ND<0.50 160 440 NA

5-5.5 DUP ND<0.50 270 930 NA10-10.5 ND<0.26 71 190 NA15-15.5 ND<0.30 620 640 NA

GP3 2.5-3 2004 ND<0.50 ND<5.0 ND<25 NA5-5.5 ND<0.50 ND<5.0 ND<25 NA

10-10.5 ND<0.24 ND<5.0 ND<25 NA15-15.5 ND<0.33 ND<5.0 ND<25 NA20-20.5 ND<0.20 840 950 NA23.5-24 ND<0.41 ND<5.0 ND<25 NA

GP4 2.5-3 2004 ND<0.50 150 210 NA5-5.5 ND<0.33 180 260 NA

10-10.5 ND<0.21 190 300 NA15-15.5 1,300 8,600 5,200 NA20-20.5 ND<0.28 ND<5.0 ND<25 NA23.5-24 0.35 ND<5.0 ND<25 NA

Notes:bgs = below ground surfacemg/kg = milligrams per kilogram"ND<" = consitituent not detected at or above the stated laboratory reporting limitNA = not analyzedTPH = total petroleum hydrocarbonsTPHd = TPH quantified as diesel (EPA Method 8015M)TPHg = TPH quantified as gasoline (EPA Method 8015M)TPHmo = TPH quantified as motor oil (EPA Method 8015M)TRPH = total recoverable petroleum hydrocarbons (EPA Method 418.1)

Page 2 of 2

Table 2-4Summary of BTEX and MTBE Concentrations in Soil



Xylenes MTBEmg/kg mg/kg mg/kg mg/kg mg/kg

B-WAT1-1 10 1991 ND<0.0012 ND<0.0012 ND<0.0012 0.0012 ND<0.001215 ND<0.0011 ND<0.0011 ND<0.0011 ND<0.0011 ND<0.0011

MW-WAT1-1 8 1991 ND<0.0012 ND<0.0012 ND<0.0012 ND<0.0012 ND<0.001212 ND<0.0012 ND<0.0012 ND<0.0012 ND<0.0012 ND<0.001218 ND<0.0011 ND<0.0011 ND<0.0011 ND<0.0011 ND<0.001120 ND<0.0011 ND<0.0011 ND<0.0011 ND<0.0011 ND<0.0011

MW-WAT1-2 4 1991 ND<0.0012 0.0013 ND<0.0012 0.0021 ND<0.00125 ND<0.0011 ND<0.0011 ND<0.0011 ND<0.0011 ND<0.001110 ND<0.0011 ND<0.0011 ND<0.0011 ND<0.0011 ND<0.0011

11.5 ND<0.0011 ND<0.0011 ND<0.0011 ND<0.0011 ND<0.001113 ND<0.0058 0.022 0.028 0.011 ND<0.0058

MW-WAT1-3 10 1991 ND<0.0012 ND<0.0012 ND<0.0012 ND<0.0012 ND<0.001213 ND<0.280 2.8 4.8 65 ND<0.28015 ND<0.280 12 11 110 ND<0.28018 ND<0.280 ND<0.280 ND<0.280 1.6 ND<0.28020 ND<0.058 0.072 0.06 0.48 ND<0.05823 ND<0.0011 0.0011 ND<0.0011 0.0024 ND<0.001125 ND<0.0011 ND<0.0011 ND<0.0011 ND<0.0011 ND<0.0011




SS-WAT1-4 1 2001 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.0052.5 ND<0.005 ND<0.005 ND<0.005 0.0064 ND<0.005






B-WAT1-2 6.5 2001 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.00510 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.00515 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005

B-WAT1-3 6.5 2001 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.00510 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.00515 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005

Boring ID

Sample Depth (feet bgs)

Date Sampled

Page 1 of 2

Table 2-4Summary of BTEX and MTBE Concentrations in Soil



Xylenes MTBEmg/kg mg/kg mg/kg mg/kg mg/kgBoring ID

Sample Depth (feet bgs)

Date Sampled

MW-WAT1-4 6.5 2001 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.00510 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.00515 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.00520 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005

MW-WAT1-5 6.5 2001 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.00510 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.00515 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.00520 ND<0.005 ND<0.005 ND<0.005 ND<0.005 ND<0.005

GP1 2.5-3 2004 ND<0.0017 ND<0.0017 ND<0.0017 ND<0.0017 NA5-5.5 ND<0.0016 ND<0.0016 ND<0.0016 ND<0.0016 NA

10-10.5 ND<0.20 ND<0.20 ND<0.20 0.52 NA15-15.5 ND<15 19 28 400 NA20-20.5 ND<0.0017 0.011 0.01 0.1 NA20-20.5 ND<0.0036 0.0047 0.0039 0.038 NA24-24.5 ND<0.0055 ND<0.0055 ND<0.0055 0.012 NA

GP2 2.5-3 2004 ND<0.0050 ND<0.0050 ND<0.0050 ND<0.0050 NA5-5.5 ND<0.0050 ND<0.0050 ND<0.0050 ND<0.0050 NA5-5.5 ND<0.0050 ND<0.0050 ND<0.0050 ND<0.0050 NA



10-10.5 ND<0.0019 ND<0.0019 ND<0.0019 ND<0.0019 NA15-15.5 ND<0.0026 ND<0.0026 ND<0.0026 ND<0.0026 NA20-20.5 ND<0.0016 ND<0.0016 ND<0.0016 ND<0.0016 NA23.5-24 ND<0.0033 ND<0.0033 ND<0.0033 ND<0.0033 NA


10-10.5 ND<0.0017 ND<0.0017 ND<0.0017 ND<0.0017 NA15-15.5 ND<8.7 ND<8.7 ND<8.7 80 NA20-20.5 ND<0.0022 0.0027 ND<0.0022 0.012 NA23.5-24 ND<0.0022 ND<0.0022 0.012 0.038 NA

Notes:

BTEX = benzene, toluene, ethylbenzene, and total xylenes

MTBE = methyl tertiary-butyl ether

mg/kg = milligrams per kilogram

"ND<" = consitituent not detected at or above the stated laboratory reporting limit

NA = not analyzed

Samples collected in 1991 were analyzed by EPA Method 8020.

Samples collected in 2001 and 2004 were analyzed by EPA Method 8021B/5035.

Page 2 of 2

Table 2-5Summary of Ammonia, Cyanide, Sulfide, and Total Phenols Concentrations in Soil



(Extractable)Total

Phenolsmg/kg mg/kg mg/kg mg/kg

EPAMethod

350.2 or350.31

335.2 or9010B2 376.1 420.1

YearMT-408-8-1 0 1986 NA ND<1.0 NA NADSS-WAT1-1 0 1991 16.7 ND<0.57 ND<2.28 NADSS-WAT1-2 0 1991 13.5 0.81 ND<2.22 NADSS-WAT1-3 0 1991 10.3 ND<0.56 ND<2.26 NADSS-WAT1-4 0 1991 19.7 ND<0.6 ND<2.42 NADSS-WAT1-5 0 1991 20.4 2.95 ND<2.14 NA

0 DUP 11.9 1.06 ND<2.16 NAB-WAT1-1 3.5 1991 4.34 ND<0.58 ND<2.23 ND<2.9

10 ND<1.76 ND<0.59 ND<2.34 ND<2.9215 ND<1.7 ND<0.57 ND<2.27 ND<2.85

MW-WAT1-1 3 1991 6.35 ND<0.58 ND<2.33 5.18 ND<1.75 ND<0.58 3.05 ND<2.9212 ND<1.73 ND<0.58 ND<2.3 ND<2.8818 ND<1.69 ND<0.56 ND<2.25 ND<2.8220 ND<1.67 ND<0.56 ND<2.22 ND<2.77

MW-WAT1-2 4 1991 6.64 5.26 ND<2.32 ND<2.95 5.23 14.3 ND<2.28 ND<2.8510 ND<1.7 0.57 ND<2.27 ND<2.85

11.5 4.11 0.66 ND<2.28 ND<2.8513 117 13.1 ND<2.34 ND<2.92

13 DUP 122 1.67 ND<2.29 5.0415 278 ND<0.58 ND<2.31 ND<2.88

MW-WAT1-3 3.5 1991 ND<3.47 ND<0.58 ND<2.31 ND<2.910 25.5 ND<0.59 ND<2.36 ND<2.9513 167 ND<0.56 ND<2.24 10.9

13 DUP 116 ND<0.57 ND<2.28 ND<2.8515 232 ND<0.56 ND<2.26 8.7918 375 ND<0.56 ND<2.25 ND<2.8220 151 ND<0.58 ND<2.32 ND<2.923 3.37 ND<0.56 ND<2.25 ND<2.8225 48.4 ND<0.57 ND<2.27 ND<2.85


SS-WAT1-2 1 2001 ND<5 ND<0.5 NA NA1 DUP ND<5 ND<0.5 NA NA



2.5 ND<5 0.62 NA NASS-WAT1-5 1 2001 ND<5 ND<0.5 NA NA

2.5 5.6 0.78 NA NA

Depth (feet)

Boring/SampleID

Page 1 of 2

Table 2-5Summary of Ammonia, Cyanide, Sulfide, and Total Phenols Concentrations in Soil



(Extractable)Total

Phenolsmg/kg mg/kg mg/kg mg/kg

EPAMethod

350.2 or350.31

335.2 or9010B2 376.1 420.1

YearDepth (feet)

Boring/SampleID





B-WAT1-2 6.5 2001 ND<0.5 ND<0.01 NA NA10 ND<0.5 ND<0.01 NA NA15 ND<0.5 ND<0.01 NA NA

B-WAT1-3 6.5 2001 ND<0.5 ND<0.01 NA NA10 ND<0.5 ND<0.01 NA NA

10 DUP ND<0.5 ND<0.01 NA NA15 ND<0.5 ND<0.01 NA NA

MW-WAT1-4 6.5 2001 ND<5 ND<0.5 NA NA10 ND<5 ND<0.5 NA NA15 ND<5 ND<0.5 NA NA20 ND<5 ND<0.5 NA NA

MW-WAT1-5 6.5 2001 ND<5 ND<0.5 NA NA10 ND<5 ND<0.5 NA NA15 ND<5 ND<0.5 NA NA20 ND<5 ND<0.5 NA NA

20 DUP ND<5 ND<0.5 NA NA

Notes: mg/kg = milligrams per kilogram "ND<" = consitituent not detected at or above the stated laboratory reporting limit NA = not analyzed

1 Samples collected in 1991 were analyzed for ammonia by EPA Method 350.2; samples collected in 2001 were analyzed for ammonia by EPA Method 350.3.2 Samples collected in 1991 were analyzed for cyanide by EPA Method 335.2; samples collected in 2001 were analyzed for cyanide by EPA Method 9010B.* Unknown Analytical Method

Page 2 of 2

Table 3-1Proposed Sampling Program and Rationale


P-1 through P-5 25 2, 5, 10, 15, 20 PAHs; TPH-p, TPH-e, BTEX

25 HOLD

Proposed Soil Gas Probe ID Total Depth

of Probe (feet bgs)

Target Soil Gas Sampling Depth Interval (feet bgs) Analyses

5 5 VOCs (including naphthalene)




Notes:

Sampling Rationale

SG-1 through SG-3 Assess presence of soil vapors in shallow soil across site and adjacent to existing building

Assess presence of soil vapors in shallow soil across site and adjacent to existing building

Obtain additional soil visual and analytical data to supplement the existing characterization dataset; Adjust sample depths as appropriate to collect most impacted soil; Visually examine 0-20’ depths for evidence of MGP waste.

Sampling RationaleProposed Soil Boring ID

If impact is observed in overlying sample, submit for analyses per tests outlined for overlying sample. If analytes in overlying sample are reported at elevated concentrations before expirations of holdingtimes, submit for appropriate analyses.

Total Depth of Boring (feet bgs)

Target Soil Sampling Depth (feet bgs) Analyses*

bgs = below ground surface

Assess presence of soil vapors in shallow soil within impacted zone

Assess presence of soil vapors in shallow soil within impacted zone

* Samples collected for TPH-p and BTEX analysis will be collected using En Core (or equivalent) sampling methods.TPH-p = purgeable total petroleum hydrocarbons quantified as gasoline (TPHg) by EPA Method 8280B

PAHs = polycyclic aromatic hydrocarbons by EPA Method 8270SIMTPH-e = extractable total petroleum hydrocarbons quantified as diesel (TPHd) and motor oil (TPHmo) by EPA Method 8015M

BTEX = benzene, toluene, ethylbenzene, and total xylenes by EPA Method 8260B

SG-4 and SG-5

VOCs = volatile organic compounds (including naphthalene) by EPA Method 8260 using onsite mobile lab, and TO-15 using stationary offsite lab.

Page 1 of 1

Table 2Summary of BTEX and TPH Analytical Results for Soil Samples


Benzene TolueneEthyl-

benzeneTotal

Xylenes TPHg TPHd TPHmoTPG-1 2/13/08 2 0.00029 J ND (0.00017) ND (0.00025) ND (0.00050) 0.038 J B 5.5 15 J

2/13/08 5 0.00075 J 0.00026 J B ND (0.00027) ND (0.00054) 0.035 J B 14 41 J2/13/08 10 ND (0.00025) 0.00023 J B ND (0.00025) ND (0.00050) 0.033 J B 0.74 J ND (9.2) 2/13/08 16 ND (0.00022) 0.00028 J B ND (0.00022) ND (0.00044) 0.057 J B 1 ND (9.2) 2/13/08 19.5 ND (0.00020) 0.00021 J B ND (0.00020) ND (0.00041) 0.041 J B 0.47 J ND (9.2) 2/13/08 23.5 0.0013 J 0.00061 J B 0.00035 J 0.00097 J B 0.13 J B 0.84 J ND (9.1)

TPG-2 2/13/08 2 0.0017 J 0.0014 J B ND (0.00025) 0.0011 J B 0.041 J B 230 6202/13/08 5 0.028 0.034 B 0.0036 J 0.034 B 0.25 B 560 1,2002/13/08 10 ND (0.00025) 0.00041 J B ND (0.00025) ND (0.00050) 0.027 J B 320 5102/13/08 15 0.00050 J 0.00039 J B 0.00021 J 0.00084 J B 0.093 J B 9.2 17 J2/13/08 20 0.00020 J 0.00026 J B ND (0.00020) ND (0.00040) 0.030 J B 0.63 J ND (9.2) 2/13/08 24.5 0.00035 J 0.00026 J B ND (0.00025) ND (0.00050) 0.037 J B 0.75 J ND (9.2)

TPG-3 2/12/08 2 ND (0.00025) ND (0.00017) ND (0.00025) ND (0.00050) 0.044 J B 180 3002/12/08 5 ND (0.00025) 0.00028 J B ND (0.00025) ND (0.00051) 0.044 J B 1.3 ND (9.2) 2/12/08 12 ND (0.31) 0.74 J B ND (0.25) 0.60 J 43 B J 1,200 9102/12/08 15 0.00027 J 0.00034 J B ND (0.00025) ND (0.00049) 0.082 J B 2.7 ND (9.2) 2/12/08 20 0.00061 J 0.00033 J B ND (0.00023) ND (0.00047) 0.088 J B 3.9 ND (9.2) 2/12/08 24.5 ND (0.00029) 0.00041 J B 0.00044 J ND (0.00057) 0.16 J B 1.7 ND (9.2)

TPG-4 2/13/08 2 0.00021 J 0.00032 J B ND (0.00020) ND (0.00040) 0.089 J B 16 32 J2/13/08 5 ND (0.00025) 0.00019 J B ND (0.00025) ND (0.00051) 0.054 J B 5.3 20 J2/13/08 10 ND (0.00026) 0.00029 J B ND (0.00026) ND (0.00051) 0.10 J B 1.1 ND (9.2) 2/13/08 15 0.00083 J 0.0026 J B 0.0037 J 0.021 0.45 B 7.5 ND (9.2) 2/13/08 20 0.0017 J 0.017 B7 0.031 0.23 4.5 B7 47 45 J2/13/08 24.5 0.00036 J 0.00035 J B ND (0.00021) ND (0.00042) 0.079 J B ND (0.37) ND (9.1)

TPG-5 2/13/08 2 0.00044 J 0.00042 J B ND (0.00023) ND (0.00045) 0.047 J B 22 1102/13/08 5 ND (0.00023) 0.00022 J B ND (0.00023) ND (0.00046) 0.070 J B 0.79 J ND (9.1) 2/13/08 10 ND (0.00029) 0.00033 J B ND (0.00029) ND (0.00058) 0.082 J B 6.3 32 J2/13/08 15 0.00047 J 0.00056 J B ND (0.00030) ND (0.00061) 0.083 J B 11 532/13/08 20 0.00033 J 0.00023 J B ND (0.00024) ND (0.00047) 0.061 J B 0.47 J ND (9.2) 2/13/08 24.5 0.00032 J 0.00033 J B ND (0.00031) ND (0.00061) 0.060 J B ND (0.38) ND (9.2)

Notes:All analytical results presented in milligrams per kilogram (mg/kg)BTEX = benzene, toluene, ethylbenzene, total xylenes (by EPA Method 8260B)TPHd = total petroleum hydrocarbons quantified as diesel (by EPA Method 8015M)TPHg = total petroleum hydrocarbons quantified as gasoline (by EPA Method 8260B)TPHmo = total petroleum hydrocarbons quantified as motor oil (by EPA Method 8015M)ND (#) = non-detect (laboratory detection limit)J = Estimated value; analyte detected at a concentration less than the reporting limit and greater than or equal to the method detection limit.B = Estimated value; analyte detected in the sample and the assocaited method blank. Analyte was detected at concentration less than 10 times the concentration detected in method blank.

TPH

Boring ID

Sample Depth (feet)

DateSampled

BTEX

Page 1 of 1

Table 3Summary of PAH Analytical Results in Soil Samples


Acena-phthene

Acena-phthylene

Anthr-acene

Benzo(ghi) perylene

Fluor-anthene Fluorene

Phen-anthrene Pyrene

TPG-1 2/13/08 2 0.00043 J 0.0013 J 0.0016 J 0.0074 0.012 0.00056 J 0.0061 0.0132/13/08 5 0.0014 J 0.02 0.022 0.033 0.081 0.0055 0.018 0.122/13/08 10 ND (0.00023) ND (0.00025) ND (0.00011) ND (0.00043) 0.00023 J ND (0.00024) 0.0004 J B 0.00027 J2/13/08 16 ND (0.00023) ND (0.00025) 0.00013 J B 0.00043 J 0.00099 J ND (0.00023) 0.00046 J B 0.0011 J2/13/08 19.5 ND (0.00023) ND (0.00025) 0.00013 J B ND (0.00043) 0.0002 J ND (0.00023) 0.0004 J B 0.0002 J2/13/08 23.5 0.011 0.0089 ND (0.00011) ND (0.00043) 0.0002 J 0.013 0.0097 ND (0.00012)

TPG-2 2/13/08 2 0.012 J 0.065 0.11 0.23 0.55 0.032 0.29 0.632/13/08 5 0.12 0.67 1.1 1.5 5.9 0.3 2.6 6.52/13/08 10 0.015 J 0.45 0.082 J 0.28 0.6 0.092 J 0.08 J 1.22/13/08 15 0.031 0.024 0.079 0.028 0.1 0.068 0.12 0.12/13/08 20 0.0022 J 0.0013 J 0.0006 J B ND (0.00043) 0.0005 J 0.00026 J 0.00056 J B 0.0006 J2/13/08 24.5 0.00083 J 0.00036 J 0.0002 J B ND (0.00043) 0.00036 J ND (0.00023) 0.00036 J B 0.00046 J

TPG-3 2/12/08 2 0.0031 J 0.066 0.1 0.14 1.1 0.023 0.048 1.22/12/08 5 ND (0.00023) 0.00047 J 0.00033 J 0.00083 J 0.0023 J 0.00027 J 0.0006 J 0.0028 J2/12/08 12 3.2 4 5 0.47 4.1 7.8 12 5.12/12/08 15 0.0015 J 0.0028 J 0.0026 J 0.0013 J 0.0033 J 0.003 J 0.005 0.0042 J2/12/08 20 0.0041 J 0.0091 0.017 0.0036 J 0.014 0.0093 0.016 0.0212/12/08 24.5 0.023 0.022 0.031 ND (0.00043) 0.015 0.054 0.0048 J 0.011

TPG-4 2/13/08 2 0.00097 J 0.049 0.09 0.071 0.48 0.01 0.16 0.482/13/08 5 ND (0.00023) 0.0058 0.0027 J 0.0051 0.012 0.001 J 0.0029 J 0.0162/13/08 10 ND (0.00023) ND (0.00025) 0.00012 J ND (0.00043) 0.00039 J ND (0.00023) 0.00033 J B 0.00054 J2/13/08 15 0.018 0.022 0.056 0.001 J 0.046 0.059 0.13 0.0382/13/08 20 0.19 0.37 0.54 0.051 0.6 0.65 1.1 0.562/13/08 24.5 0.004 J 0.00033 J 0.00017 J B ND (0.00043) 0.0003 J ND (0.00023) 0.00046 J B 0.00027 J

TPG-5 2/13/08 2 ND (0.00046) 0.00052 J 0.00063 J 0.0016 J 0.0044 J ND (0.00047) 0.0038 J 0.0051 J2/13/08 5 0.0014 J 0.0011 J 0.0051 0.0014 J 0.0068 0.0036 J 0.0017 J 0.00662/13/08 10 ND (0.00023) 0.001 J 0.0014 J 0.0014 J 0.0051 0.00087 J 0.0065 0.00542/13/08 15 ND (0.00047) 0.0013 J 0.0017 J 0.0018 J 0.0071 J 0.00096 J 0.0062 J 0.0076 J2/13/08 20 ND (0.00023) 0.00043 J 0.00059 J ND (0.00043) 0.0012 J 0.00056 J 0.00056 J B 0.0012 J2/13/08 24.5 ND (0.00023) 0.00039 J 0.00048 J 0.00051 J 0.0003 J ND (0.00023) ND (0.00016) 0.00045 J

Boring ID

Sample Depth (feet)

DateSampled

NON-CARCINOGENIC PAHs

Page 1 of 2

Table 3Summary of PAH Analytical Results in Soil Samples


TPG-1 2/13/08 22/13/08 52/13/08 102/13/08 162/13/08 19.52/13/08 23.5

TPG-2 2/13/08 22/13/08 52/13/08 102/13/08 152/13/08 202/13/08 24.5

TPG-3 2/12/08 22/12/08 52/12/08 122/12/08 152/12/08 202/12/08 24.5

TPG-4 2/13/08 22/13/08 52/13/08 102/13/08 152/13/08 202/13/08 24.5

TPG-5 2/13/08 22/13/08 52/13/08 102/13/08 152/13/08 202/13/08 24.5

Boring ID

Sample Depth (feet)

DateSampled

Naph-thalene

0.01 0.0073 0.016 ND (0.00015) 0 0.0083 0.0012 J 0.0061 0.00099 J B 0.01100.098 0.086 0.1 0.032 0.083 0.021 0.034 0.0024 J B 0.1204

0.00053 J B ND (0.0003) 0 ND (0.00043) 0 ND (0.00015) 0 0.00023 J B ND (0.00037) 0 ND (0.00037) 0 0.00043 J B 0.00030.0012 J B 0.00059 J 0.00089 J 0.00026 J 0.00069 J B ND (0.00037) 0 ND (0.00037) 0 0.0003 J B 0.0009

0.00076 J B ND (0.0003) 0 ND (0.00043) 0 ND (0.00015) 0 0.00017 J B ND (0.00037) 0 ND (0.00037) 0 0.00079 J B 0.00030.00093 J B ND (0.0003) 0 ND (0.00043) 0 ND (0.00015) 0 0.00026 J B ND (0.00037) 0 ND (0.00037) 0 0.0042 J 0.0004

0.57 0.61 1 ND (0.00076) 0 0.45 0.052 0.23 0.02 J 0.81227 5.9 8.5 1.8 4.2 0.56 1.6 0.33 8.0224

0.6 0.75 0.77 0.32 0.53 0.09 J 0.27 0.011 J 0.98190.058 0.055 0.056 0.022 0.052 0.008 0.025 0.026 0.0743

0.0006 J B ND (0.0003) 0 0.00063 J ND (0.00015) 0 0.00036 J B ND (0.00037) 0 ND (0.00037) 0 0.00073 J B 0.00040.0006 J B ND (0.0003) 0 0.00043 J ND (0.00015) 0 0.00026 J B ND (0.00037) 0 ND (0.00037) 0 0.00093 J B 0.0003

1 0.59 0.55 0.25 0.71 0.056 0.16 0.0029 J 0.81210.0015 J 0.0017 J 0.0034 J ND (0.00015) 0 0.0021 J ND (0.00037) 0 0.00077 J 0.00063 J 0.0024

2.7 1.5 1.6 0.39 2.4 0.12 J 0.44 8.4 2.07780.0033 J B 0.0031 J 0.0031 J 0.0015 J 0.0026 J 0.0012 J 0.0013 J 0.0054 0.0045

0.01 0.0099 0.0085 0.0034 J 0.0091 ND (0.00037) 0 0.003 J 0.0037 J 0.01250.0011 J B 0.0009 J 0.00076 J 0.0003 J 0.00096 J B ND (0.00037) 0 ND (0.00037) 0 0.003 J 0.0012

0.45 0.3 0.41 0.12 0.31 0.029 0.08 0.0037 J 0.41900.019 0.018 0.024 0.0064 0.013 0.0018 J 0.0052 0.00042 J B 0.0242

0.0013 J B 0.00055 J ND (0.00043) 0 ND (0.00015) 0 0.0005 J B ND (0.00037) 0 ND (0.00037) 0 0.00046 J B 0.00080.014 0.0056 0.0057 0.0021 J 0.0055 0.00041 J 0.0013 J 0.065 0.0081

0.3 0.19 0.21 0.097 0.25 0.028 0.063 1.2 0.26900.0003 J B ND (0.0003) 0 ND (0.00043) 0 ND (0.00015) 0 0.00023 J ND (0.00037) 0 ND (0.00037) 0 0.0006 J B 0.00030.0033 J 0.0018 J 0.0035 J ND (0.0003) 0.0049 J ND (0.00074) 0 0.001 J 0.00078 J B 0.00280.0019 J B 0.0022 J 0.0025 J 0.00099 J 0.0028 J ND (0.00037) 0 0.0011 J 0.0003 J B 0.00290.0038 J B 0.002 J 0.003 J ND (0.00015) 0 0.0028 J 0.00045 J 0.0011 J 0.00096 J B 0.00300.0067 J 0.0032 J 0.0051 J ND (0.00031) 0 0.0047 J ND (0.00075) 0 0.0015 J 0.0026 J B 0.0047

0.00093 J B ND (0.0003) 0 0.00053 J ND (0.00015) 0 0.00086 J B ND (0.00037) 0 ND (0.00037) 0 0.00069 J B 0.00040.002 J B 0.00064 J ND (0.00043) 0 ND (0.00015) 0 0.00064 J B ND (0.00037) 0 0.00041 J 0.00065 J B 0.0010

Notes:All analytical results presented in milligrams per kilogram (mg/kg)PAH = polycyclic aromatic hydrocarbon (by EPA Method 8270SIM)ND (#) = non-detect (laboratory detection limit)B(a)P Equivalent = benzo(a)pyrene equivalent concentration, which is representative of the total carcinogenic PAH concentrationJ = Estimated value; analyte detected at a concentration less than the reporting limit and greater than or equal to the method detection limit.B = Estimated value; analyte detected in the sample and the assocaited method blank. Analyte was detected at concentration less than 10 times the concentration detected in method blank.

CARCINOGENIC PAHs

B(a)P Equivalent

Benzo(a) anthracene Benzo(a) pyrene

Benzo(b) fluoranthene Chrysene

Dibenzo(a,h)

anthracene

Indeno(1,2,3-cd) pyrene

Benzo(k) fluoranthene

Page 2 of 2

Table 4Summary of Metals Analytical Results for Soil Samples


METALS

Antimony Arsenic Barium Beryllium Cadmium Chromium Cobalt Copper Lead Mercury Molybdenum Nickel Selenium Silver Thallium Vanadium ZincTPG-1 2/13/08 2 ND (0.053) 4.4 130 0.75 0.95 33 6.7 18 6 ND (0.0010) 0.61 J B 26 ND (0.11) 0.071 J ND (0.075) 38 50

2/13/08 5 ND (0.052) 5.1 130 0.59 0.34 J 31 8.2 19 7.8 0.056 0.55 J 29 0.28 J 0.13 J 0.095 J 35 1002/13/08 10 ND (0.053) 2.4 86 0.39 J 0.10 J 25 6.2 8.8 3.8 0.029 J 0.16 J 18 ND (0.11) 0.030 J ND (0.075) 33 212/13/08 16 ND (0.050) 2.6 95 0.40 J 0.17 J 45 8.3 9.6 4 0.025 J 0.46 J 38 ND (0.10) 0.043 J ND (0.071) 30 262/13/08 19.5 ND (0.053) 3.2 140 0.34 J 0.19 J 55 10 13 3.2 0.039 J ND (0.044) 71 ND (0.11) 0.045 J ND (0.075) 29 362/13/08 23.5 ND (0.050) 1.4 140 0.35 J 0.19 J 69 11 18 4.2 0.077 ND (0.041) 110 ND (0.10) 0.048 J ND (0.071) 30 44

TPG-2 2/13/08 2 ND (0.050) 7.5 97 0.44 J 1.1 35 7.1 24 39 0.096 0.29 J B 38 ND (0.11) 0.12 J ND (0.072) 26 1202/13/08 5 ND (0.052) 5.9 160 0.59 0.9 32 6.7 16 38 0.21 0.41 J B 38 ND (0.11) 0.10 J ND (0.075) 30 552/13/08 10 ND (0.055) 2.1 54 0.50 J 0.82 39 8.1 8.3 2.7 0.037 J 0.24 J B 43 ND (0.11) 0.031 J ND (0.078) 29 242/13/08 15 ND (0.053) 2.7 88 0.48 J 0.64 43 7.1 9.8 14 0.055 0.84 J B 39 ND (0.11) 0.046 J ND (0.076) 27 272/13/08 20 ND (0.052) 2.6 70 0.35 J 0.55 41 7.5 8.1 2.3 0.031 J 0.11 J B 65 ND (0.11) 0.025 J ND (0.074) 21 212/13/08 24.5 ND (0.053) 3.1 130 0.74 1.2 84 11 19 2.7 0.034 J 0.31 J B 110 ND (0.11) 0.030 J ND (0.075) 45 36

TPG-3 2/12/08 2 ND (0.050) 3.6 95 0.38 J 0.23 J 26 6.7 11 4.2 0.09 0.16 J 22 0.42 J 0.058 J ND (0.072) 31 322/12/08 5 ND (0.051) 3.3 100 0.54 0.16 J 32 6.4 12 4.8 0.035 J 0.44 J 25 ND (0.11) 0.058 J ND (0.073) 40 292/12/08 12 ND (0.053) 2.2 110 0.27 J 0.19 J 40 8.2 11 3.4 0.045 J 0.44 J 65 ND (0.11) 0.066 J ND (0.076) 22 222/12/08 15 ND (0.054) 3 130 0.24 J 0.16 J 78 8.6 13 3.7 0.048 J 0.12 J 84 ND (0.11) 0.057 J ND (0.077) 30 222/12/08 20 ND (0.055) 1.8 71 0.21 J 0.11 J 54 8.6 11 2 0.029 J ND (0.045) 65 ND (0.12) 0.053 J ND (0.079) 31 212/12/08 24.5 ND (0.051) 1.7 150 0.43 J 0.17 J 41 12 23 4.8 0.091 ND (0.042) 100 ND (0.11) 0.049 J ND (0.073) 28 48

TPG-4 2/13/08 2 ND (0.050) 7.5 100 0.67 0.9 55 9.9 16 11 0.095 0.38 J B 45 ND (0.10) 0.048 J ND (0.071) 35 382/13/08 5 ND (0.050) 3.6 110 0.75 0.85 38 6.2 12 4.7 0.021 J 0.38 J B 25 ND (0.11) 0.019 J ND (0.072) 45 332/13/08 10 ND (0.051) 2.8 58 0.48 J 0.7 38 6.4 6.8 2.4 0.029 J 0.15 J B 39 ND (0.11) 0.020 J ND (0.073) 25 222/13/08 15 ND (0.051) 1.8 59 0.33 J 0.51 45 6.6 6.9 2 0.055 0.18 J B 58 ND (0.11) 0.025 J ND (0.073) 21 202/13/08 20 ND (0.052) 3.7 170 0.59 0.92 75 10 20 2.8 0.062 3.1 B 120 ND (0.11) 0.069 J ND (0.074) 34 272/13/08 24.5 ND (0.051) 2.4 98 0.45 J 0.74 59 10 13 2.4 0.28 0.27 J B 77 ND (0.11) 0.044 J ND (0.073) 34 27

TPG-5 2/13/08 2 ND (0.053) 2.6 110 0.56 0.69 26 7.1 15 4.3 0.021 J 0.90 J B 21 ND (0.11) 0.041 J 0.18 J B 33 292/13/08 5 ND (0.052) 3 110 0.75 0.72 34 10 11 4 0.038 J 0.43 J B 25 ND (0.11) 0.035 J ND (0.074) 39 252/13/08 10 ND (0.052) 3.2 130 0.72 0.98 91 7.4 12 3.5 0.041 J 1.5 B 72 ND (0.11) 0.045 J ND (0.075) 34 322/13/08 15 ND (0.054) 3.1 110 0.61 0.89 70 9.2 14 2.9 ND (0.00099) 1.7 B 66 ND (0.11) 0.052 J ND (0.077) 40 282/13/08 20 ND (0.053) 4.2 120 0.62 1 59 9.5 19 3.6 0.042 J 0.18 J B 110 ND (0.11) 0.046 J ND (0.076) 32 382/13/08 24.5 ND (0.054) 2.3 83 0.41 J 0.64 49 7.3 10 2.6 0.036 J 0.072 J B 61 ND (0.11) 0.031 J ND (0.077) 24 26

Notes:All analytical results presented in milligrams per kilogram (mg/kg)Metals analyzed using EPA Method 6010/7471ND (#) = non-detect (laboratory detection limit)J = Estimated value; analyte detected at a concentration less than the reporting limit and greater than or equal to the method detection limit.B = Estimated value; analyte detected in the sample and the assocaited method blank. Analyte was detected at concentration less than 10 times the concentration detected in method blank.

Boring ID

Date Sampled

Sample Depth (feet)

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Table 5Summary of Analytical Results for Soil Gas Samples


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SG-1 5 2/13/08 ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) 0.013 ND (0.007) ND (0.007) NDSG-2 5 2/13/08 ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) 0.015 ND (0.007) ND (0.007) ND

15 2/13/08 ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) 0.037 ND (0.007) ND (0.007) ND(Dup) 15 2/13/08 ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) 0.02 ND (0.007) ND (0.007) NDSG-3 5 2/13/08 ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) 0.042 ND (0.007) ND (0.007) ND

15 2/13/08 ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) 0.083 ND (0.007) ND (0.007) NDSG-4 5 2/12/08 ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) 0.571 ND (0.007) ND (0.007) 0.525 ND (0.007) ND (0.007) ND (0.007) 9.45 ND (0.007) 3.16 ND

15 2/12/08 1.13 1.24 ND (0.007) ND (0.007) ND (0.007) 41.5 ND (0.007) ND (0.007) 26.5 1.65 ND (0.007) ND (0.007) 445 ND (0.007) 130 ND(Dup) 15 2/12/08 1.23 1.18 ND (0.007) ND (0.007) ND (0.007) 43.7 ND (0.007) ND (0.007) 27.3 0.824 ND (0.007) ND (0.007) 501 ND (0.007) 145 NDSG-5 5 2/13/08 ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) 0.059 ND (0.007) ND (0.007) ND

15 2/12/08 ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) 0.214 ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) 1.56 ND (0.007) ND (0.007) NDSG-6 5 2/12/08 ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) 0.608 ND (0.007) ND (0.007) 0.94 ND (0.007) ND (0.007) ND (0.007) 5.97 ND (0.007) 6 ND

15 2/12/08 ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) 19.1* ND (0.007) ND (0.007) 10.4 0.441 ND (0.007) ND (0.007) 99.3* ND (0.007) 24.7 NDSG-7 5 2/12/08 ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) 0.051 ND (0.007) ND (0.007) 1.26 ND (0.007) ND (0.007) ND (0.007) 2.01 ND (0.007) 16 ND(1P) 15 2/12/08 ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) 1.19 ND (0.007) ND (0.007) 0.358 ND (0.007) ND (0.007) ND (0.007) 6.97 ND (0.007) 1.1 ND(3P) 15 2/12/08 ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) 0.725 ND (0.007) ND (0.007) 5.82 ND (0.007) ND (0.007) ND (0.007) 14.6 ND (0.007) 4.19 ND(7P) 15 2/12/08 ND (0.007) ND (0.007) ND (0.007) ND (0.007) ND (0.007) 0.372 ND (0.007) ND (0.007) 10.4 ND (0.007) ND (0.007) ND (0.007) 12.8 ND (0.007) 115 ND

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SG-2 15 2/12/08 0.0051 ND (0.0024) 0.0055 0.004 0.032 0.03 0.019 0.0038 0.0044 NA 0.0016 0.0035 JA 0.041 0.0027 0.024 NDSG-4 5 2/12/08 0.033 0.025 ND (0.0058) 0.046 0.026 0.0093 0.0084 ND (0.003) 0.015 NA ND (0.002) 0.03 JA 0.096 ND (0.0044) 0.430 ND

Notes:Units are presented in micrograms per Liter (ug/L)dup = duplicate sample1P, 3P, 7P = Purge test of one, three and seven purge volumesJA = Estimated value because of interference by non-target compounds NA = not analyzedND (#) = non-detect (laboratory detection limit)* = Sample required dilution

VOCs including Naphthalene (EPA Method 8260B)

VOCs including Naphthalene (EPA Method TO-15)

Sample Date

Sample Depth (feet)Station ID

Sample Date

Sample Depth (feet)Station ID

Page 1 of 1

APPENDIX B

DEED RESTRICTION

APPENDIX C

QUALITY ASSURANCE/QUALITY CONTROL PLAN

Removal Action Workplan Former Watsonville-1 MGP Site

Page C-1

QUALITY ASSURANCE/QUALITY CONTROL PLAN

C1.0 INTRODUCTION

Quality Assurance (QA) is an integral part of all projects performed by Terra Pacific Group Incorporated (TPG), particularly those involving collection and analysis of field and laboratory data. QA is not merely a series of requirements and procedures, but is a management discipline which results in validated and verifiable information. Moreover, QA is a discipline which begins with effective and conscientious work planning and ends with a carefully constructed set of checks designed to ensure that uncertainty has been reduced to a known and practical minimum.

C2.0 QA/QC OBJECTIVES

The goal of the QA program is to assure that all environmental data obtained will be scientifically valid, defensible, of known quality and that reports are correct and accurate. This goal will be achieved by: (1) planning for QA and allocation of adequate resources as part of the initial planning for data collection and analysis efforts, (2) incorporating specific QA procedures into the entire process (from initial planning through data usage), and (3) assigning appropriately trained and experienced staff to perform the tasks. The following sections discuss specific quality assurance/quality control (QA/QC) procedures used for manufactured gas plant (MGP) site remediation sampling, data analyses, and report preparation. These same procedures will be applied to this project.

C3.0 QA/QC PROCEDURES FOR SAMPLING

For this remediation sampling, procedures specified in the United States Environmental Protection Agency (USEPA) guidance for Superfund investigations (i.e., Scientific and Technical Standards for Hazardous Waste Site, Volume 1: Site Characterization) will be used.

General procedures, specified throughout this Removal Action Workplan (RAW), will be used for all activities related to remediation. Calibration of equipment and maintenance procedures follow manufacturers’ written instructions or accepted standard procedures.

C4.0 COLLECTION OF QA/QC SAMPLES

Additional samples will be collected to quantify potential sources of variability in the field and in the laboratory. The QA/QC samples will be labeled so that the laboratory staff cannot identify them as QA samples or cannot associate them with another primary sample.

Soil gas samples will be collected using purging and sampling techniques as outlined in the Soil Gas Sampling section of the RAW. Soil gas samples and duplicate/replicate sample(s) will be collected using SUMMATM canisters and analyzed for volatile organic compounds (VOCs; including naphthalene) by the off-site stationary laboratory using USEPA Method TO-15. In accordance with Department of Toxic Substances Control (DTSC) protocol, duplicate/replicate samples will be


Page C-2

collected at a rate of one (1) duplicate/replicate sample per 20 samples or per batch shipment to the laboratory, whichever is more often.

Groundwater samples will be collected using low flow purging and sampling techniques as outlined in the Groundwater Sampling section of the RAW. Groundwater samples from each well, and one duplicate sample and one equipment blank sample, will be analyzed for: purgeable total petroleum hydrocarbons (TPH-p) quantified as gasoline (TPHg) by USEPA Method 8260B, extractable total petroleum hydrocarbons (TPH-e) quantified as diesel (TPHd) and motor oil (TPHmo) by USEPA Method 8015M; benzene, toluene, ethylbenzene and total xylenes (BTEX) and methyl tertiary-butyl ether (MTBE) by USEPA Method 8260B; PAH by USEPA Method 8270SIM; total cyanide by USEPA Method 335.2; ammonia as nitrogen by USEPA Method 350.2; and arsenic by USEPA Method 6010B. One trip blank sample will also be analyzed for TPH-p (as TPHg) and BTEX.

C5.0 USE OF PROPER SAMPLE HANDING PROCEDURES

C5.1 CHAIN OF CUSTODY

The possession and handling of samples should be traceable from the time of collection, through analysis, until first disposition. Components of the chain of custody (sample labels and seals, a field log book, chain of custody record, and sample analysis request form) and procedures for their use are described in the following sections. Sample custody procedures will follow the USEPA and DTSC guidance procedures.

A sample is considered to be under a person’s custody if it is: (1) in a person’s physical possession; (2) in view of the persons after he/she has taken possession; (3) secured by the person so that no one can tamper with the sample; and (4) secured by that person in an area that is restricted to unauthorized personnel. To establish the documentation necessary to trace sample possession from the time of collection, a chain of custody record must be filled out and accompany every sample. Standard forms have been developed for labeling samples and tracing chain of custody. The person who collects the sample initially fills out the chain of custody form. Each person who later receives the samples must sign the form. Samples must not be left unattended unless they are secured and sealed.

C5.2 SAMPLE LABELS Sample labels are necessary to prevent misidentification of samples. Gummed paper labels will be affixed to sample containers prior to or at the time of sampling. The sample labels will be filled out at the time of sample collection. The sample label will identify each sample with the appropriate sample identification. The exact sample location and type of sample will be recorded in the Sample Log Book.

C5.3 DOCUMENTATION The most important aspect of sample custody is through record keeping. At the time of sampling, the sample identification code will be entered into a Field Log Book along with date and time of


Page C-3

sample collection, sample type and depth, and name of person collecting the sample. The types of chemical analyses requested will also be listed.

C5.4 SHIPPING Samples will be packaged and hand delivered or shipped according to the United States (U.S.) Department of Transportation and USEPA regulations. Samples will be delivered to the laboratory on a timely basis, preferably on the same day of collection, so that the requested analyses can be performed within the specified allowable holding times. Samples will be accompanied by a completed chain-of-custody record. The chain-of-custody will list the variables to be analyzed by the laboratory and the total number and type of samples shipped for analysis. Authorized laboratory personnel will acknowledge receipt of shipment and condition of samples upon receipt by signing and dating the form and returning a copy to TPG. The laboratory will record the temperature inside of the cooler on the chain-of-custody form. For hand delivered samples, the chain-of-custody form will be signed by an authorized laboratory staff member and a copy of it given to the person delivering the samples. A copy is also sent with the completed laboratory analysis results.

C5.5 USE OF USEPA-RECOMMENDED LABORATORY PROCEDURES Standard USEPA methods will be used for all analyses as listed previously in this RAW. All analyses will be performed by laboratories certified by the State of California to perform such analyses.

C5.6 FIELD EQUIPMENT CALIBRATION AND MAINTENANCE Equipment related to health and safety concerns (i.e., organic vapor analyzer [OVA] and Miniram dust monitor) are discussed in the Health and Safety Plan.

C5.7 LABORATORY DATA VALIDATION The laboratory will prepare the following samples to check internal accuracy and precision:

• Matrix spike samples to provide percent recovery; and

• Matrix spike duplicates to check precision.

The laboratory data will be evaluated to see that units are correct, detection limits are provided, all analyses of the blanks are below detection, and that holding time requirements (i.e., 7 days for extraction of organics) have been met. The percent recoveries from the matrix spike analyses will be checked to see that they are within the prescribed limits (± 25 percent). Duplicate samples will be used to determine the relative percent difference. This value should be within ± 20 percent for water and ± 35 percent for soil/residue samples when values are greater than five times the detection limit. For values below detection limit, the difference should be equal to the detection limit or less. The coefficient of variation for the replicate samples is then determined, and ideally should be low. All the data will be checked to be sure that the desired detection limits, are achieved. The desired detection limits are the standard detection limits for each of the analytical methods proposed in the RAW. Any questionable values or cases with high detection limits will be rechecked with the laboratory and, if needed, will be rerun.


Page C-4

C6.0 QA/QC AUDITS AND CORRECTION ACTIONS

Audits of data quality involve assessments of the methods used to collect, interpret, and report information. The assessment entails a detailed review of: (1) the recording and transfer of raw data; (2) data calculations; (3) documentation of procedures, particularly changes from those stated in the RAW; and (4) verification that all available information has been used in the interpretation. This assessment will be completed prior to preparing report conclusions.

Field audits of sampling and documentation procedures will be conducted by TPG staff. Any variances between actual procedures and those in the RAW will be brought to the attention of the Project Manager. Necessary changes to the RAW (i.e., relocating a borehole location) will be noted in the Field Log Book and explained in the Closure Report. Other variances (i.e., incomplete record in Sample Log Book) will be corrected as soon as identified.

Audits of the laboratory will be made if data problems occur such as several blank samples with contamination or high variances among replicate samples. Calibration procedures including control charts and documentation will be reviewed at this time. Corrective actions such as changing analytical methods will be suggested, if necessary, to minimize matrix interference problems.

C7.0 QA/QC FOR REVIEW OF DOCUMENTS

As a final step to ensure that project objectives are met, TPG will conduct formal review of draft and final reports prior to their release. Draft reports may be reviewed by senior staff familiar with the project objectives but who were not involved in the preparation of the report. This helps identify sections of the report which may not be clearly written or where more detailed substantiation of results is needed. Review of reports involving calculations will include rechecking the computations, review of assumptions used and the rationale for input data, and checking the input data against the original sources to be sure that one of the most common of all problems, transcription errors, has not occurred.

C8.0 QUALITY ASSURANCE OBJECTIVES FOR MEASUREMENT DATA

Data quality objectives (DQOs) are qualitative and quantitative statements developed to specify the quality of data from field and laboratory collection activities to support specific decisions or regulatory actions. The DQOs describe what data are needed, why the data are needed, and how the data will be used to address the problem. DQOs also establish numeric limits for the data to determine whether data collected are of sufficient quality for use in their intended application. Data needs for the remedial activities include both screening measurements and data of sufficient quality to be used in achieving cleanup objectives.

The USEPA has established a hierarchy of DQOs that specify the quality of data required to support regulatory decisions during remedial response (USEPA, 1987). Table C-1 provides a summary of anlaytical levels appropriate to data uses during work activities. For data collected, the main analytical program will be performed at Level III protocol at a stationary laboratory. Site-specific health and safety screening and measurement of parameters during environmental sample


Page C-5

collection will be at Level I protocol. Quality criteria to be employed at the Property address the following data characteristics: accuracy, precision, completeness, representativeness, and comparability. These criteria are discussed below.

C9.0 DEFINITION OF CRITERIA

Accuracy

Accuracy is the degree of agreement of a measurement or average of measurements with an accepted reference or "true" value, and is a measure of bias in the system. For this project, accuracy of the measured data will be assessed and controlled. Field instruments have a potential accuracy which is specified by the manufacturer. The ability to obtain this level of accuracy depends on proper calibration. For the laboratory, results of method blank analysis, as well as reagent, matrix, and surrogate QC sample results will be the primary indicators of accuracy. These results will be used to control accuracy within acceptable limits by requiring that specific criteria be met. As these spiked QC samples are analyzed, spike recoveries will be calculated and compared to pre-established laboratory acceptance limits.

The calculation formula for percent recovery is:

% Spike Recovery = (Value of Sample Plus Spike Added) - (Value of Unspiked Sample) X 100 (Value of Spike Added)

Acceptance criteria, also termed "control limits," will be based on previously established (i.e., historical) laboratory capabilities for similar samples using control chart techniques. In this approach, the control limits reflect the minimum and maximum recoveries expected for individual measurements to establish that the system was in control. Recoveries outside the established control limits indicate some assignable cause, other than normal measurement error, and the possible need for corrective action. Corrective action could include recalibration of the instrument, reanalysis of the QC sample, reanalysis of the samples in the batch, or flagging the data as suspect if the problem cannot be resolved. These results will be reported to the Project Manager.

Resampling may be performed if samples exceed their specific holding time requirements or are not preserved properly. If second column analysis, where appropriate, is not performed within the specified holding time, resampling may be undertaken.

Precision

Precision is a measure of mutual agreement among individual measurements of the same property under prescribed similar conditions.

Precision is defined as a measure of mutual agreement of a measurement or average of measurements with an accepted reference of "true" value. Based on these results, a measure of bias within the system can be estimated. Precision of the measurement data gathered during work activities at the Property will be based on QC sample analyses (repeatability), replicate analyses (replicability), and results obtained from duplicate/replicate field samples (sample replicability).


Page C-6

Precision is independent of the error (accuracy) of the analyses and reflects only the degree to which the measurements agree with one another, not the degree to which they agree with the "true" value for the parameter measured.

Precision is calculated in terms of relative percent difference (RPD), which is expressed as follows:

(X1 - X2) RPD = X 100

[(X1 + X2)/2] where:

X1 and X2 represent the individual values for the target analyte in the two replicate analyses.

RPDs must be compared to the laboratory established RPD for the analysis. For concentrations less than 10 times the detection limit, RPD criteria are not valid, and variations may be as great as 100 percent. Precision of duplicates may again depend on sample homogeneity. Initial spike concentrations will be greater than the detection limits and will have a range comparable to those stated in pertinent USEPA guidelines.

When RPDs exceed previously established control limits, the analyst or his/her supervisor must investigate why the data exceed stated acceptance limits and report these findings to the Project Manager. RPDs outside the established control limits can indicate some assignable cause, other than normal measurements errors, and the need for corrective action. Follow-up action can include recalibration, reanalysis of the matrix spike/matrix spike duplicates (MS/MSD) or a duplicate QC sample, environmental sample reanalysis, or flagging the data as suspect if problems cannot be resolved.

Replicate analysis of control samples will be obtained when QC samples specific to the environmental samples are analyzed. Analytical precision will be evaluated from MS/MSD RPD analyses. Use of duplicate samples during analysis can also allow a measure of precision to be determined.

Field duplicates are defined as two samples collected independently at a single sampling location during a single act of sampling. Field duplicates will be acquired at a rate of 1 per 20 environmental samples, or 5 percent of the total number.

A field replicate is defined as a single sample that is collected, then divided into two equal parts for the purpose of analysis of two samples representative of one soil sample. Field replicates will be acquired at a rate of 1 per 20 environmental samples, or 5 percent of the total number. Field replicates will be collected for soil/sediment samples and analyzed for the same parameters. Discretely sampled field duplicates/replicates are useful in determining sampling variability. However, differences greater than expected between replicates may occur because of variability in the sample material. In these instances, a visual examination of the sample material will be performed to document the reason for the difference. Field sample duplicates/replicates shall be


Page C-7

used as a QC measure to monitor precision relative to sample collection activities. Analytical precision shall be evaluated using RPDs for MS/MSD, or duplicate samples.

Completeness

Completeness is a measure of the amount of valid data obtained from a measurement system compared to the amount expected under correct, normal conditions.

The target value for completeness of all parameters is 100 percent. Measurement data completeness is a measure of the extent that the database resulting from a specific measurement activity fulfills the objectives for the amount of data required. For this program, completeness will be defined as the valid data percentage of the total test requested as follows:

Completeness (%) = No. of Successful Analyses X 100

No. of Requested Analyses Successful analyses are defined as those in which the sample arrived at the laboratory intact, properly preserved, in sufficient quantity to perform the requested analyses, and accompanied by a completed chain-of-custody form. Furthermore, the sample must be analyzed within the specified holding time and according to QC acceptance criteria.

Completeness for the entire project also involves elements specific to field and laboratory documentation of sample collection. This includes documentation detailing whether samples and analyses specified in the RAW have been processed using the procedures as specified, and whether laboratory’s standard operating procedures have been implemented.

Representativeness

Representativeness expresses the degree to which data accurately and precisely represent a characteristic of a population, parameter variations at a sampling point, a process condition, or an environmental condition.

Representativeness describes how well the data reflect Property conditions in the vicinity of the data point at the time of collection. Representativeness may be maintained or attained by careful documentation of data collection procedures and adherence to standard data collection procedures.

The characteristics of representativeness are usually not quantifiable. Subjective factors to be taken into account are as follows:

• Degree of homogeneity of a site;

• Degree of homogeneity of a sample taken from one point in a site; and

• Available information on which a sample plan is based.


Page C-8

Field duplicates and field replicates, as defined under precision, are also used to assess representativeness. Two samples that are collected at the same location and at the same time are considered to be equally representative of the Site at a given point in space and time. Soil borings will be chosen to represent the areas of interest at the Site. To maximize representativeness of results, sampling techniques, sample size, sample locations, and depths will be carefully selected so they provide laboratory samples that are representative of the Site and specific area. Samples exhibiting obvious stratification or lithologic changes should not be used as replicates. The analytical laboratory will take precautions to extract from the sample an aliquot representative of the whole sample. The soil sample is mixed and foreign objects are removed; then the sample is passed through a 1-millimeter sieve. An aliquot is removed for analysis. For samples requiring volatile analysis, premixing or homogenizing samples will be avoided.

Comparability

Comparability expresses the confidence with which one dataset can be compared to another data set measuring the same property. Comparability is ensured through the use of established and approved sample collection techniques and analytical methods, consistency in the basis of analytes (wet weight, volume, etc.), consistency in reporting units, and analysis of standard reference materials.

Comparability is the degree to which data from separate, datasets may be compared. For instance, sample data may be compared to data from background locations to established criteria or to data from earlier sampling events. Comparability is attained by careful adherence to standardized sampling procedures and rigorous documentation of sample locations (including depth, time, and date).

Data comparability will be achieved by using standard units of measure as specified for metals, inorganics, and organics in soil samples.

The use of standardized methods to collect and analyze samples (i.e., American Society for Testing and Materials [ASTM] and USEPA methods), along with instruments calibrated against National Institute for Standards and Technology (NIST) and USEPA-traceable standards, will also ensure comparability.

Comparability also depends on other data quality characteristics. Datasets can be compared with confidence only when data are judged to be representative of the environmental conditions, and when precision and accuracy are known.

C10.0 GOALS FOR ASSESSMENT CRITERIA

Project quality objectives for various measurement parameters associated with the remediation activities cannot be quantified for representativeness and comparability. The following elements delineate assessment criteria discussed in detail elsewhere in this QA/QC plan:

• Laboratory accuracy limits and analytical precision criteria will be assessed to the current standard for each method;


Page C-9

• Overall precision for the work at the Site, which includes both sampling and analytical factors, can be expected to show RPDs up to 40 percent for soil samples; and

• A completeness factor of 90 percent is acceptable for the work at the Site.

of 1

Table C-1 Summary of Analytical Levels Appropriate to Data Uses

(According to USEPA Guidelines 1987)

DATA USES

ANALYTICAL LEVEL

TYPE OF ANALYSES

LIMITATIONS

DATA QUALITY OBJECTIVE

Site Characterization; Monitoring During Implementation

Level I Total organic/inorganic vapor detection using portable instruments, field determination of pH, conductivity Field test kits

Instruments respond to naturally occurring compounds

Can provide indication of contamination if instruments are calibrated and data are interpreted correctly

Site Characterization; Evaluation of Alternatives; Engineering Design; Monitoring During Implementation

Level II Variety of organics by gas chromatography during soil gas survey, geophysical survey to determine depth to bedrock; buried landfill materials; point counting of asbestos fibers using plane polarized microscopy Detection limits vary from low parts per million to low parts per billion

Tentative identification Dependent on QA/QC steps employed

Risk Assessment; Site Characterization; Evaluation of Alternatives; Engineering Design; Monitoring During Implementation

Level III Organics/inorganics using USEPA procedures other than CLP; can be analyte specific RCRA characteristics tests

Tentative identification in some cases Can provide data of same quality as Level IV

Similar detection limits to CLP Less rigorous QA/QC

Risk Assessment; Evaluation of Alternatives; Engineering Design

Level IV Hazardous Substance List; organics/inorganics by gas chromatography/mass spectroscopy; atomic absorption; inductively coupled plasma Low parts per billion detection limit

Tentative identification of non-hazardous substance list parameters Some time may be required for validation of packages

Goal is data of known quality Rigorous QA/QC

Risk Assessment Level V Nonconventional parameters Method-specific detection limits Modification of existing methods Appendix 8 parameters

May require method development/modification Mechanism to obtain services requires special lead time

Method-specific

APPENDIX D

RESPONSIVENESS SUMMARY

FORMER WATSONVILLE-1 MANUFACTURED GAS PLANT 618 MAIN STREET, WATSONVILLE, CALIFORNIA

RESPONSIVENESS SUMMARY PUBLIC COMMENTS ON THE DRAFT REMOVAL ACTION WORKPLAN

1.0 Introduction The purpose of a Responsiveness Summary is to present a written response by the Department of Toxic Substances Control (DTSC) to public comments received on the Draft Removal Action Workplan (RAW). The environmental investigations conducted on the portion of the Former Watsonville-1 Manufactured Gas Plant (MGP) located on the property at 618 Main Street in Watsonville, California (“the Site”) found areas at the Site where soil, soil gas, and groundwater were impacted with contaminants from the former MGP. A Draft Removal Action Workplan (RAW) has been prepared which identifies the proposed removal actions to address contamination on the Site. The contaminants include polycyclic aromatic hydrocarbons (PAHs; including naphthalene), total petroleum hydrocarbons (TPH), volatile organic compounds (VOCs), and metals. The Draft RAW was made available to the public during a comment period that ran from June 27, 2011 through July 31, 2011. DTSC placed a notice in the Register Pajaronian newspaper on June 25, 2011 that announced the comment period. DTSC also prepared a fact sheet that announced the comment period and described the proposed cleanup method presented in the Draft RAW. The fact sheet was mailed out on June 23, 2011 to 622 individuals and organizations on the Site mailing list. The mailing list includes residents near the Site; elected officials, government agencies, environmental organizations, and other interested parties; and the DTSC Statewide Mandatory Mailing List. A copy of the fact sheet and newspaper notice is included as Attachment A. This Responsiveness Summary is organized as follows: Section 1 is the Introduction. Section 2 provides the Site Location. Section 3 provides a brief Site History and Summary of Site Investigations. Section 4 provides the topics discussed in the Draft RAW. Section 5 is the comments on the Draft RAW and DTSC’s responses Section 6 discusses the finalization and implementation of the Final RAW and lists

the repositories where Site-related documents can be reviewed by the public. Attachment A includes a copy of the fact sheet and the newspaper public notice. 2.0 Site Location The 0.4-acre project site is located at the intersection of East Fifth Street and Main Street, in the downtown area of the City of Watsonville, California. The Assessor Parcel Number (APN) is 018-151-26.

Former Watsonville-1 Manufactured Gas Plant Site Page 2 October 2011 RAW Responsiveness Summary

3.0 Site History and Summary of Site Investigations The Site was previously part of a larger property where a MGP was originally constructed in 1871. MGP operations ceased sometime prior to 1905. From 1905 to 1931, the Site was used for various purposes including; a schoolhouse, automobile painting and trimming shop, automobile dealership, and auto repair shop. In 1931, Coast Counties Gas and Electric Company (CCG&E) constructed the existing building on the Site for a customer service center. The northeastern end of the property where gas manufacturing had been conducted was sold to private parties in 1935. CCG&E continued to use the remaining portion of the property (the Site) as a customer service center until it was sold to PG&E in 1954. PG&E used the Site as a customer service center until 1989, when it leased the Site for use as a restaurant. The Site is currently privately-owned and occupied by Jalisco’s, a Mexican restaurant. The Site is bordered by a bank to the northwest, a commercial property to the northeast, a market to the southeast, and Main Street to the southwest. Residential properties exist approximately 100 feet north of the Site. Several environmental investigations were conducted at the Site since 1985. These investigations have indicated that soil, soil gas and groundwater are impacted by MGP residual chemicals. The maximum concentrations of contaminants of concern (COCs) in soil at up to 20 feet below ground surface at the Site are PAHs expressed as benzo(a)pyrene (B(a)P) at 21 milligrams per kilogram (mg/kg); naphthalene at 320 mg/kg; total petroleum hydrocarbons (TPH) as gasoline at 5,300 mg/kg, TPH-diesel at 14,000 mg/kg, TPH-motor oil at 9,500 mg/kg, and arsenic at 10 mg/kg. The maximum concentrations of COCs in soil gas are benzene at 43.7 micrograms per liter (µg/L), ethylbenzene at 309 µg/L, toluene at 1,320 µg/L, xylenes at 2,170 µg/L, and naphthalene at 85.8 µg/L. Based on semiannual groundwater sampling data from the past five years, the maximum concentrations of COCs in groundwater are naphthalene at 460 µg/L, benzene at 41 µg/L, TPH-gasoline at 4,200 µg/L, and TPH-diesel at 5,800 µg/L. 4.0 Draft Removal Action Workplan The Draft RAW was prepared in accordance with the California Health and Safety Code, Section 25356.1. The purpose of the RAW is to choose and describe a cleanup alternative for the Site to address the PAHs (including naphthalene), TPH, VOCs, and metals in soil, soil gas, and groundwater that is protective of public health and safety and the environment. RAWs are prepared for sites where the projected cleanup costs are less than two million dollars. The RAW includes:


a description of the on-site contamination; the objectives or goals to be achieved by the removal action; a streamlined risk evaluation to assist in focusing the removal action goals on particular

chemicals and exposure pathways of concern; development of appropriate removal action alternatives, and analysis of these

alternatives; and comparison of the alternatives, selection of a preferred alternative, and explanation of

the basis for the selection.

5.0 Comments and Responses on the Draft RAW This section provides responses to written comments received during the public comment period. Comment 1 From: Mr. Robert Ketley, City of Watsonville Improved Site Access The City continues to believe that soil alternatives 3 and 4 (Excavation of Impacted Soil and Offsite Treatment and Excavation of Impacted Soil and Offsite Disposal) would be more cost-effective if access to the Site from an adjacent property can be arranged. It is our understanding that the owners of the 25 East Fifth Street (the property behind 618 Main St.) are willing to discuss this matter. This option could also provide better access to contaminated soils. Cooperative Remediation of MGP Site Sanborn maps indicate that the MGP facility was located on land now occupied by 618 Main St. and 25 East Fifth Street. By working with owners of 25 East Fifth Street, it may be possible to conduct a more effective cleanup of the overall site. A more aggressive and cooperative remedial effort addressing relic contamination that stretches across property lines will effectively reduce long term monitoring costs, the negative perception of blighted lands, and future deed restrictions for both properties. We urge DTSC and PG&E to work with the owners of 25 East Fifth Street to more fully evaluate the opportunities provided by a cooperative approach to cleanup at this location.


Response 1: As discussed in the Draft RAW, the selected soil Alternative No. 2 (Capping with Institutional Control and Focused Excavation with Offsite Disposal) will adequately remediate the Site and provide for the protection of human health and the environment. We understand that working with the owners of 25 East Fifth Street would provide better access to facilitate the contaminated soils cleanup at the Site or even provide a cooperative approach to cleanup of the entire former MGP property. However, the Site and 25 East Fifth Street property are in different stages in the cleanup process. The Site has been fully investigated and has a Remediation Investigation Report approved by DTSC. Sanborn Company maps and other historical documents show that MGP operations were performed on the 25 East Fifth Street property. Some investigation of the 25 East Fifth Street property has been performed; however, more extensive soil, soil gas, and groundwater investigation are needed to fully understand the extent of contamination before a cleanup plan can be developed. DTSC has been working with PG&E since 2006 in developing the cleanup plan for the Site and DTSC, PG&E, and the current property owner desire to move forward in implementing the cleanup plan rather than waiting until the 25 East Fifth Street property is fully investigated and a cleanup plan developed. DTSC has had a number of discussions with PG&E, and they are willing to revisit the proposed Site remedy in the future, provided that they obtain the current property owner’s agreement. This would enable a more comprehensive approach to the entire former MGP site, should the remaining portions of the former MGP site be remediated in the future. DTSC also has a five-year review process, where every five years, cleanups that involve leaving contaminants above levels that allow for unrestricted land use are reevaluated to determine if they continue to be protective of human health and the environment. When the 25 East Fifth Street property is fully investigated, a more comprehensive cleanup approach for both properties can be evaluated and considered. Even if PG&E is allowed access from the 25 East Fifth Street property for their Site cleanup, Alternatives 3 and 4 could significantly impact the business and operation of Jalisco’s restaurant. The extensive soil removal proposals in Alternatives 3 or 4 would disrupt the restaurant’s business because soil contamination occurs over 20 feet below ground surface, with the highest concentrations in the 10 to 20 foot depth range. With the more extensive removal proposed in Alternatives 3 and 4, the cleanup timeframe would be extended to more than 3 months and would potentially result in dust and odor emissions in close proximity to the restaurant and neighboring businesses. Another consideration is that the Site is downgradient from the MGP operations that occurred on the 25 East Fifth St. property and more extensive contamination might be present there. There is a possibility of soil recontamination if an extensive soil removal is proposed and backfilled with clean materials.


Comment 2 From: Mr. Robert Bosso, Esq, representing Philip and Martha Oneto, owners of 25 East Fifth Street property, Watsonville, California This office represents Philip and Martha Oneto who are the current owners of property located at 25th East Fifth Street, Watsonville, California. That property is immediately adjacent to the site discussed in the above referenced draft plan (Draft Removal Action Workplan) and is the property referred to in that plan as “the northeastern end of the MGP, where gas manufacturing had primarily been conducted was sold to private parties in 1935…” Prior to the acquisition by PG&E, its predecessors, including Coast Counties Gas & Electric which PG&E acquired, had operated the manufactured gas plant on both parcels which is the source of all the contamination from 1871 forward. The plant was never operated solely on the parcel owned by our clients as the report seems to suggest. It was one integrated operation until the operation of the gas plant was moved to another location in Watsonville. Our clients are two retirees in their 80s who purchased the East Fifth Street, Watsonville site as part of their investment for retirement. They are not capable of the costs of clean up projected in the report and believe that PG&E, as successor to Coast Counties Gas & Electric and its predecessor, should be responsible for the cleanup which extends across both sites. A preliminary screening of the Oneto property has indicated that soil and water contamination on the Oneto site has a fingerprint of “gasification plant” contamination similar to concentrations on the Jalisco site currently being remediated. We would request that the CAP encapsulation remedial solution for the Jalisco parcel be extended to the Oneto property given that:

1. The contamination is almost certainly associated with the 100 year old gasification plant wastes.

2. PG&E’s claims that equitable and fairness principles bar the overseeing regulatory agencies from assigning shares of a cleanup based on corporate successor liability standards should recognize they are a direct successor to the entities which caused the problems.

3. The Onetos are retirees with limited assets and do not have the financial wherewithal to complete 25 years of assessment work that has been done of the Jalisco property.

4. There are similar subsurface/source conditions: a. Groundwater: There appears to be no significant groundwater

contamination.


b. Soils: Preliminary results of site soil tests show residual “gasification waste” soil concentrations generally lower than the Jalisco site.

Response 2: DTSC has evaluated the cleanup liability of PG&E and found that PG&E is only responsible for the cleanup of the parcel at 618 Main Street. Coast Counties Gas and Electric (CCG&E) and its immediate predecessor, Coast Counties Light and Power Company, did not succeed to the liability of the MGP facility owners and operators because, at the time of CCG&E's 1954 merger into PG&E, those entities assumed no liability from Watsonville Maxim Gas Company, Watsonville Gas Company or Watsonville Light and Power. DTSC’s decision was based upon review of the acquisition papers and other documentation obtained from PG&E. We agree that the former MGP operations caused the contamination on both properties. The proposed remedy for the 618 Main Street site may not be applicable for the 25 East Fifth Street property until it has been fully investigated. The 618 Main Street property has had extensive soil, soil gas, and groundwater samples taken and DTSC has approved a Remediation Investigation Report. From historical documents, DTSC believes that the bulk of the MGP operations occurred at the 25 East Fifth Street property. Although some soil and groundwater samples were performed at the 25 East Fifth Street, DTSC would require additional soil, soil gas, and groundwater investigation to fully understand the extent of the contamination before a cleanup plan can be developed. As the current property owner, the Onetos are potentially responsible for the cleanup of their property even though they never operated the former MGP facility. DTSC understands that they may not have the financial resources for the investigation and cleanup of their property. We are willing to discuss with the Onetos how to proceed with addressing contamination on their property. DTSC will be initiating an effort to identify other potential responsible parties for the 25th East Fifth Street property. 6.0 Final Removal Action Workplan This Responsiveness Summary is included in the Final RAW as Appendix D. The Notice of Exemption, which was prepared in compliance with the California Environmental Quality Act, is included in the Final RAW as Appendix E. Implementation of the RAW is scheduled to begin in February 2012. The Final RAW and other documents related to the Site are available for viewing at:


Attachment A Copy of Fact Sheet and Newspaper Notice

toxic harm. p

The Department of Toxic Substances Control (DTSC)to inform the community about Pacific Gas and Eproposed

is issuing this fact sheet lectric Company’s (PG&E’s)

cleanup he former Watsonville-1 manuf rred to in this fact sheet as the site)

n Watsonville. DTSC is the lead state

activities at

plan for the portion of tactured gas plant (MGP) site (refe

located at 618 Main Street in downtowregulatory agency providing oversight of the investigation and cleanup

the site.

Fact Sheet, June 2011

Draft Removal Action WorkPortion of PG&E

planr Watsonville-1 Forme

ed Gas PlantManufacturWatsonville, California

PUBLIC COMMENT PEJune 27 – July 31, 2011

RIOD

oval Action Workplan Act (CEQA) Notice of us investigations and the

The draft RAW and other site-related docum positories listed on page 4 of this fact sheet.

DTSC is holding nt period beginning June 27, 2011, and ending July 31, 2011. Al marked by July 31, 2011. All emailed comm 5:00 p.m. on that same day. Please submit your comments to:

Henry Chui DTSC Project Manager

700 Heinz Avenue, Berkeley, CA 94710

(510) 540-3759 .ca.gov

DTSC encourages you to review and comment on the draft Rem(draft RAW) and related California Environmental Quality Exemption for the site. The draft RAW describes the previoproposed cleanup activities for the site.

ents are available at the information re

a 30 ommel c e post

ents must be received no later than

hchui@dtsc

-day public comments must b

Printed on recycled paper

including PAimpacts are generallynortheastern portion ofongoing monitoring of chemicals ap

Hs and VOCs. Groundwater limited to the

the site and PG&E’s indicates concentrations

pear to be naturally decreasing rea groundwater is not used for

y other purposes.

to the Public an immediate health als or plants in the

te. A Human Health Risk mpleted for the site to

els of petroleum hydrocarbons, sent in soil and

fe for future on-site ased on this study,

termined there are some contaminants present from past MGP

above DTSC’s protective verall cleanup plan

or the site for long-term ealth and the

ning-level health risk cted based on recent soil

gas sampling results to address the possibility s present in the subsurface could

avel through soil and into the potentially impact the

r air. Results of the evaluation uality in the building

ceptable for its current ercial use.

n Objective he draft RAW is to

summarize and evaluate the nature and extent of impacts at the site and to identify a preferred alternative which prevents or reduces potential risks to public health and the environment. Cleanup alternatives are evaluated based on effectiveness, ability to be implemented, and cost.

Before DTSC makes a final decision to approve, modify, or deny a RAW, it is made available for public review and comment

over time. Adrinking water or an

No Health RisksThe site does not pose risk to the public, animvicinity of the siAssessment was codetermine if levPAHs and VOCs pregroundwater are saworkers and visitors. BDTSC has de

operations that arestandards and that an oshould be developed fprotection of public henvironment.

In addition, a screeevaluation was condu

that chemicalvaporize and trbuilding which could quality of indooindicated that the air qwould not be impacted and thus would be considered safe and accomm

Draft Cleanup PlaThe objective of t

IntroductionAs a result of past gas manufacturwhich occurred on the site inthe site became contaminated by gmanufacturing residuals. Thlampblack which contains polycychydrocarbons (PAHs), total petrohydrocarbons (TPH) and volatile compounds (VOCs) in select aregas (the pockets of air in the soil)groundwater at the site. PG&E icombined cleanup approach that iexcavation of site soils, cap

ing act the early 1

as ese include

lic aroleumorganic

as of so and

s proposnclude

ping areas of of groundwater

t donitorised.

y at 6 Ci

buildinn of th&E c

ant. Tts of a paved

djacent p

larger pWatson

tsonville-1 MGP was origs shut down i

ite wascial Gas a

y constructed a customer ich was latering was

vestigationsSince 1985, a series of environmental investigations have been conducted at the site. Results of soil and soil gas sampling indicated that select areas of site soils contain the residues of historic MGP operations including PAHs, TPH, and VOCs.

Groundwater beneath the site contains relatively low levels of MGP residues

ivities800’s,

service office at the site, whby PG&E. In 1989, the buildconverted into its current use as a restaurant.

matic

il, soil

ing a s the and eedng of

site, ongoing monitoringsoil gas. An amendment of the currenrestriction on the site to require msite conditions is also being propo

Site Description and HistorThe site is half an acre and is locatedStreet in the downtown section of the

18 Main ty of g is e site ustomer he

lanters.

Watsonville. A 4,000-square-footlocated on the southwestern portiowhich was previously used as a PGservice center and is now a restaurremainder of the site consisdriveway and parking lot with a

The site was previously part of a that was occupied by the former

arcelville-1inallyn used

nd

MGP. The Waconstructed in 1871 and wa1905. From 1905 until 1931, the sfor a variety of industrial/commerpurposes. In 1931, Coast CountiesElectric Compan

used

Site In

2

during a 30-day public comment pericomments are reviewed a

ond considere

setting, usage and access were also considered in

d. All d before

il, soil gas

DTSC approves the final RAW.

Cleanup Alternatives Evaluated A variety of cleanup alternatives for soand groundwater were evaluated. The current site

evaluating alternatives animals from comisoil gas and groundwater. alternatives, with the exceAlternative which is usedcom

to prevent people and ng in contact with site soil,

Each of these ption of the No Action as a basis for

parison, would adequately remediate the site and provide for protection of human health and the environment.

3

Cleanup Alternatives Evaluated

tivesSoil – AlternaEvaluated

Soil Alternative Summary

No Action Nothing would be done with soil at the site; this is used to compare other alternatives against.

Capping, Institutional Parking lot areas of the site would be stripped of existing asphalt, re-graded and repaved,Controls, Focused planter areas of the site with exposed soil would be excavated and

Excavation with Off-Site backfilled with clean soil, deed restrictions would remain in place to limit certain Disposal types of site use and provide procedures for digging in soil underneath the cap and

maintaining the cap. Excavation of Impacted

mentImpacted soil underneath the parking lot would be excavated and treated off-site at an appSoil and Off-Site Treat ropriate permitted facility. The soil could then be reused, but would not be reused at the site.

Excavation of Impacted Impacted soil underneath the parking lot would be excavated and disposed of at Soil and Off-Site Disposal an appropriate permitted landfill facility. Soil Gas – AlteEvaluated

rnatives Soil Gas Alternative Summary

No Action Nothing would be done with soil gas at the site; this is used to compare other alternatives against.

Soil Gas Monitoring and Soil gas levels would be regularly monitored until the soil gas source is removedInstitutional Controls and deed restrictions would continue on the site limiting future building

construction without coordinating such construction with DTSC. Soil Vapor Extraction and A system to actively extract and treat impacted soil gas would be constructed; soil

gas levels would be moniTreatment, Soil Gas tored regularly to ensure they are declining or until Monitoring and discontinuation is approved by DTSC, and deed restrictions would remain on the Institutional Controls site.Groundwater – Alternatives Evaluated

Groundwater Alternative Summary

No Action Nothing would be done with groundwater at the site; this is used to compare other alternatives against.

Monitored Natural Groundwater at the site would be monitored on a regular basis to confirm that Attenuation levels of chemicals are naturally declining over time. In-Situ Bioremediation Groundwater at the site would be actively treated in-place to stimulate the natural

decline of chemicals in the groundwater.

Recommended Cleanup AlternBased on evaluation of the cleanup aDTSC recommends focused excavaand continued institutional controlsaddition, DTSC recommends reguland continued institutional controlsand monitored natural attenuationgro

atltern

tio for soar m for so

for undwater. These alternatives offer

can bg and

g activities would be perfrna

itebs

00 cu c yards phalt with a small backhoe from

o feet

a tr

areas

alt aot ar

d

of all site ndsc

lety plan will be prepared to

guide all remediation work. In addition, the following actions will be implemented during this

sure public safety and to minimize dust: Installing temporary fencing with

windscreens for security and dust control;

Driving all vehicles at slow speeds while on the property and streets;

Spraying or misting of work areas with clean water to control dust;

ivesatives,

n, capping il. In

onitoringil gas,

long-term protection of the community andimplemented given the site settin

e readily limited

ormed tives:

water , bushes

access.

The followinunder the DTSC recommended alte

Removal of asphalt paving, on-sdrainage system, and small shruand vegetation;

Removal of approximately 3of soil and as

bi

planter areas to a depth of tw ;

uck and/or

with

Placement of excavated soil inbin for off-site disposal;

Backfill of excavated planterclean, imported soil;

Placement of 4 inches of asphl

nd/orea;

rainage

concrete on existing parking

Construction of new storm watersystem on-site; and

Cleanup and restorationincluding placement of new la

areasaping.

eanupSafety & Dust Control During CA site-specific saf

Covering stockpiles w

process to en

ith plastic sheeting;

Securing trucks with covers before they leave

k tires entering and exiting the nd debris; and

Monitoring the air at, and around the , the site to ensure the amount of

levels.

on for Cleanup Notice of Exemption

ed cleanup, as required by ental Quality Act ment states that the

ot have a significant ent

because of the relatively small amount of contaminated soil to be removed, short project

led manner in which the e dug out, loaded onto an approved/permitted l.

Next Steps comment period, DTSC

er any public comments necessary revisions to the

to final approval. Also, a document will be mailed

ent and address.

oved, cleanup activities will likely begin in early 2012. Cleanup and restoration activities will last about ten weeks, and will occur between the hours of 7:00 a.m. and 5:00 p.m., Monday through Friday.

Trucks transporting soil from and to the site will only use city-approved truck routes. After the cleanup process is completed, soil testing will be conducted to confirm cleanup goals have been achieved and then PG&E will submit a Removal Action Completion Report to DTSC for review and approval.

4

the site;

Brushing trucsite to remove soil a

perimeters ofdust stays at safe

Notice of ExemptiDTSC has prepared a (NOE) for the proposthe California Environm(CEQA). The NOE docuproposed cleanup will nimpact on human health and the environm

duration, and the controlcontaminated soils will btrucks and taken away to facility for lawful disposa

At the end of the public will review and considreceived and make anydraft RAW prior Response to Comments to everyone who submits a commprovides their name and

If the draft RAW is appr

5

Where to Find Project DocumentDTSC encourages you to review the drNOE, and other site-related documeavaila

saft RA

nts which re ble at the information repositories listed

c Library

0 am – 8:00 pSubstances Control

700 Heinz Avenue, Berkeley, CA 94710

5:00 p.m

s and o online

W, a

below:

Watsonville Publi275 Main Street Suite 100 Watsonville, CA 95076 (831) 768-4300 Hours: Monday – Thursday, 9:3 mDepartment of Toxic Regional Records Office

(510) 540-3800 Please call for an appointment Hours: Monday – Friday, 8:00 a.m. –

Who to Contact for MIf you have an

ore Informationy questions about the project or

cleanup activities, please contact:

SC Project Manager (510) 540-3759

ov

Henry Chui DT

[email protected]

nica Lopez-Villasenor Public Participation Specialist

oll-Free (886) 495-5651 (Press 5 and 3)or (916) 255-3651

.ca.gov

VeroDTSCT

vlopezvi@dtsc

Media Inquiries:

Officer

.Jeanne Garcia

Copies of key technical reports, fact sheetsite-related information are also availableDTSC’s website: at

DTSC Public Information(818) 717-6593 [email protected]

therat

www.envirostor.dtsc.ca.gov.

All documents made available to the public by the DTSC can be made ava

e planguag sand federal

l

Notice to Hearing-Impaired Individuals u can obtain additional information about the

e by using the California State Relay Service 7-5378 (TDD). Ask them to contact

Veronica Lopez-Villasenor at (916) 255-3651 project.

ilable in an alternate rint, etc.) or in another format (i.e. Braille, larg

e a appropriate, in accordance with state law. Please contact Veronica Lopez-

Vil asenor for assistance.

Yositat 1 (888) 87

regarding the

Summary of Proposed Cleanup

mer Watsonville-1

Under this plan, about 300 cubic yards of soil and asphalt (approximately 25 e site; excavated areas

led with clean soil and a new asphalt parking lot (cap) will be constructed.

The cleanup work will last up to 10 weeks.

Measures to protect the community will be used throughout the entire project including: on-site and fence line dust monitoring, wetting soils to suppress dust, covering soil piles, stopping work on windy days, and others.

The cleanup plan is available for public review and comment date June 27, 2011 through July 31, 2011.

DTSC is proposing a cleanup plan for a portion of the formanufactured gas plant site previously owned by PG&E.

truckloads) will be excavated (dug up) and removed from thwill be backfil

toxic harm. p

El Departamento de Control de Sustancias Tóxicas (DTSC) einformativa para informar a la comunidad sobre el plan de li

stá emitiendo esta hoja mpieza propuesto por la

compañía Pacific Gas and Electric (PG&E’s) para la porción de la antigua planta de gas manufa de Watsonville-1, referida de aquí en

in Street en el centro de Watsonville. El dades de

cturado (MGP) en la propiedad adelante como el sitio), ubicada en la 618 MaDTSC es la principal agencia reguladora que supervisa las activiinvestigación y limpieza en el sitio.

Hoja informativa, Juno 2011

a

Proyecto del plan de trabajo Una porción de la anterior plant

de remocióna de gas

manufacturado en l propiedad de PG&E en Watsonville-1

PERÍODO D DE COMENTARIOS PÚBLICOS

mienda que revise y proyecto RAW) y el Aviso

e California (CEQA) para el sitio. El anteproyecto RAW d aciones previas y las actividades de limpieza propuestas para este

Los documentos de acionados al sitio, están a su disposición en los repositorios ind ta hoja informativa. El DTSC está programando un período 30 días mentarios por parte del público comenzando el Juno 27, 2011 y los comentarios deben ser recibidos a más tardar hasta las 5:00 p o día. Por favor presente sus comentarios a:

Henry Chui Gerente del proyecto del DTSC

700 Heinz Avenue Berkeley, CA 94710

(510) 540-3759 .ca.gov

E PRESENTACIÓN

escribe las investigsitio.

l otros relicad 4 de espa de co

terminando el Julio 31, 2011. Todosm. en ese mism

hchui@dtsc

Juno 27 a Julio 31, 2011 El Departamento de Control de Sustancias Tóxicas (DTSC) le recocomente sobre el anteproyecto del plan de trabajo de remoción (antede Exención relacionado a la Ley de Calidad Ambiental d

anteproyecto RAWos en la página

ra la presentación

Imprimido en papel reciclado

Introducción Como resultado de las actividades anmanufactura que ocurrieron en prdurante el inicio de los 1800, propiedcontaminó con los residuos prodmanufactura de gas, incluyendo el nque contienen hidrocarburos aropolicíclicos (PAH), hidrocarburos topetróleo (TPH) y compuestos orgán(VOC) en el suelo, gas del suesubterráneas del lugar. La PG&E estproponiendo un enfoque combinado dque incluye la excavación de los scubriendo con una capa las áreas del sitio, monitoreando con

propiedad y el continuoPG&E está indicando quproductos químicos medi

monitoreo por parte de la e las concentraciones de

parecen estar disminuyendo a da que pasa el tiempo. No se están usando las

l área para beber o para o.

a la salud del público ta riesgo inmediato a la salud nimales o de las plantas

iedad. Se ha completado una le riesgo a la salud

ara determinar si los de petróleo, PAHs y elo y en las aguas n un peligro para los

entro del sitio. En base a , el DTSC ha determinado que existen

debido a las operaciones de P que están sobre las normas

as por el DTSC y que se plan de limpieza general del

ción a largo plazo de la salud io ambiente.

a evaluación sobre el nivel resultados recientes del

suelo, para tratar sobre la la presencia de productos

e se podrían vaporizar y cia el edificio, lo cual

a calidad del aire interno. Los ción indicaron que la

icio no estaría afectado y do seguro y aceptable

tual.

ecto del plan de

proyecto RAW es resumir y y el alcance de los impactos

en el sitio e identificar una alternativa de preferencia que eviten o se reduzcan los posibles riesgos para la salud pública y del medio ambiente. Las alternativas de limpieza son evaluadas en base a la eficacia, capacidad de ser aplicadas y el costo. Antes de que el DTSC tome una decisión final para aprobar, modificar o negar un RAW, éste será puesto a la disponibilidad del público para que presenten sus comentarios durante el período programado de 30 días. Todos los comentarios serán revisados y considerados antes de que el DTSC apruebe el RAW final.

aguas subterráneas decualquier otro propósit

No existen riesgos Este sitio no presendel público, de los acercanas a la propevaluación sobre el posibhumana para este sitio pniveles de hidrocarburosVOCs presentes en el susubterráneas no presentatrabajadores o visitantes deste estudioalgunos contaminantes la antigua planta MGde protección requeriddebería desarrollar un lugar para la protecdel público y del medAdemás, se condujo unde riesgo en base a los muestreo de gas en el posibilidad de que químicos en la superficirecorrer por el suelo hapodría afectar a lresultados de la evaluacalidad de aire en el edifpor lo tanto sería considera

l acpara su uso comercia

Objetivo del anteproylimpieza El objetivo de un anteevaluar la naturaleza

terioresopiedades

ades siucidos por

egro delmáticos

tales deicos volá

lo y las aguas á e limp

uelos del s

tinuamente el gas de las agsuelo (bolsas de air

a ción eonito

de media at en la secci

n la la icio deutiliza

tes de la Pe resta de la p

un lote dyacentes.

arte dena antigua pla

-1, que fuy cerradel sitio f

ropósitos el 1989, el ed

aurante

ducien una serie de investigaciones ambientales en la

ad. Los resultados de los análisis de las muestras tomadas del suelo y del gas del suelo indican que áreas seleccionadas del suelo del sitio contienen residuos de las operaciones de la MPG antigua que incluyen PAH, TPH y VOC. Las aguas subterráneas debajo del terreno contienen niveles relativamente bajos de los residuos de gas manufacturado que incluyen PAHs y VOCs. Los impactos en las aguas subterráneas generalmente se limitan a la porción noreste de la

de sitio tio se

industriales o comerciales. Enfue convertido a lo que hoy es un rest

Estudios de la propiedad Desde el año 1985, se han estado con

la humo

tiles

ieza itio,

uas e en la

n

subterráneas y el gas del tierra). También se está proponiendo unmodificación del documento de restricpropiedades sitio que requiera de un mlas condiciones del sitio. Descripción e historia del sitio La propiedad tiene una superficieubicada sobre la 618 Main Stree

reo de

cre y está ón del porción 4,000 do como

centro de la ciudad de Watsonville. Esuroeste del sitio está ubicado un edifpies cuadrados que antiguamente fue un centro de servicio para los clienes ahora un restaurante. Lo quconsiste de una entrada de coches y estacionamiento con maceteros ad

G&E y ropiedad e

un nta de e

La propiedad era anteriormente una plote más grande ocupado por ugas manufacturado en Watsonvilleconstruida originalmente en el 1871 1905. Desde el 1905 hasta el 1931, utilizado para una variedad de p

a en el ue

ificio .

do

propied

2

Opciones de limpieza propuesta Se evaluaron una variedad de alternativasdel suelo, gas del suelo y de las aguas sTambién se consideró la configuración alugar, así como su uso y acceso para evaluaalternativas que prevengan el contacto direcpersonas y animales con el suelo, el gas deaguas subterráneas de la propiedad.alternativas, con la excepción de la de No

de limpieza bterráneas. ctual del

r las to de las

u

Cada una de estas Acción, que

se usa como base de compadecuadamente el lugar y proporcionarían la

m

l suelo y las

aración, remediarían

protección a la salud hu ana y del medio ambiente.

Limpieza recomendada El DTSC recomienda el enfoqutierra, la cobertura y el control cción. Además, el DTSC recoy control institucional regulartrolar la atenuación natural d

la

e en la excavación de la ontinuo de una instituí-

mienda un control regular del gas del suelo, y con-

e las aguas sub-terráneas. protección a largo plazo de

lmente implementadas dada la configuración del lugar y su acceso limitado. Las siguientes actividades serán realizarán en el

rco de las alternativas recomendadas por el DTSC:

3

Estas alternativas ofrecenla comunidad y pueden ser fáci

ma

Las alternativas de remediación evaluadas

eloAlternativas del suEvaluada

Resumen de la alternativa del suelo

Sin acción No se haría nada con la tierra del sitio; Esto se usaría como entre otras alternativas.

Tapando con una capa, Control institucional, enfoque en la excavación con eliminación fuera del sitio

Las áreas de estacionamiento del sitio serían despojadas del asfalto existente, reniveladas y vueltas a pavimentar; las áreas de , las áreas de plantación del sitio con el suelo expuesto serían excavadas y rellenadas con tierra limpia; el documento con restricciones permanecerá en su lugar para limitar cierto tipo de uso del sitio y proporcionar procedimientos de excavación del suelo debajo de la tapa, y manteniéndo la misma.

Excavación del suelo impactado y tratamiento fuera del lugar.

El suelo impactado debajo del lugar de estacionamiento sera excavado y tratado en un vertero de afuera. El suelo podría ser reusado, pero no en el mismo lugar.

Excavación del suelo impactado y eliminación fuera del lugar

El suelo impactado debajo del lugar de estacionamiento sería excavado y desechado en una instalación permitida y adecuada. La tierra podrá ser reusada entonces, pero no en el sitio.

Gas del suelo – Alteevaluada

rnatia Resumen de la alternativa del gas del suelo

Sin acción No se haría nada con el gas del suelo en el lugar; esto se usaría para comparar entre otras alternativas.

Monitoreo y contol institucional del gas del suelo

Los niveles del gas en el suelo serían controlados regularmente hasta que eliminar la fuente de gas del suelo, siguiendo con el control institucional en el lugar y el documento con restricciones seguiría para el sitio, limitando la construcción de edificios futuros sin coordinar dicha construcción con el DTSC.

Extracción del vapor del Un sistema para extraer y tratar de manera activa el gas del suelo impactado, los niveles de gas en el suelo serían controlados de manera regular para asegurar que suelo y tratamiento,

monitoreo del gas del suelo se están reduciendo o hasta que se apruebe la discontinuacíon por parte del DTSC, y control institucional y el documento con restricciones premanecería en el lugar. Aguas subterráneas – Alternativas evaluadas

Resúmen de la alternativa de las aguas subterráneas

Sin acción No se haría nada con las aguas subterráneas en el lugar; esto se usaría como comparación entre otras alternativas.

Control de la atenuación Las aguas subterráneas en el lugar serían cotroladas de manera reulgar para natural confirmar que los niveles de los productos químicos están disminuyendo de

manera natural a medida que pasa el tiempo. Bioremediación in-situ Las aguas sunterráneas en el lugar serían tratadas de manera activa en el lugar

para estimular la declinación natural de los productos químicos en las aguas subterráneas.

Aviso de exención con relación a la limpieza El DTSC ha preparadopara la limpieza propuesta, de Calidad Ambiental de California (CEQA). documento NOE declara qafectará de ninguna maneraambiente debido a que cantidad de tierra conta

Remoción del pavimento asfaltado, ee l

mente

s

tierra excavada enión fue

n

altci

a de

daón

Seguridad y control del polvo durante la

ridn.ur

púb

on brisas lvo

bajapropiedad y las ca

de ttrolar el polvo;

Tapando las reservas con láminas de

Asegurando los camiones con cubiertsalir de la propiedad;

o los neumáticos de los camiones que entran y salen de la propiedad, para eliminar la suciedad y los escombros, y;

Controlando el aire en el sitio y alreadedor de los perímetros para asegurar que la cantidad de polvo se mantenga a niveles seguros.

l sistema de os pequeños

300 yardas

de ies;

un camión ra del sitio;

drenaje de las aguas pluviales , y darbustos, matorrales y vegetación;

La eliminación de aproximadacúbicas de tierra y asfalto con una retroexcavadora pequeña de las áreaplantación a una profundidad de dos p

La colocación de la y/o recipiente para su eliminac

El relleno de las zonas de plantaciócon tierra limpia e importada;

excavadas

La colocación de 4 pulgadas de asfconcreto en el área existente de esta

o y/o onamiento;

drenaje de La construcción del nuevo sistemaguas pluviales en el lugar, y

La limpieza y restauración de todel lugar incluyendo la colocacijardines.

s las áreas de nuevos

limpieza Se preparará un plan específico de segupara guiar todo el trabajo de remediació

ad del sitio Además, se ante este lico y para

implementarán las siguientes acciones dproceso para proteger la seguridad del reducir al mínimo el polvo: Instalando una cerca provisional c para

para la protección y control del po

Manejando todos los vehículos a mientas están en la

;

velocidad, lles;

bajo con Rociando y nebulizando las áreas agua limpia para con

ra

plástico;

as antes de

Cepilland

un Aviso de exención (NOE) como requerido por la Ley

El ue la limpieza propuesta no a la salud humana y del

es relativamente pequeña la minada a ser removida, es un

ecto de corta duración y la manera de controlar la vada, cargada a los

instalación aprobada o a ser desechada.

o de comentarios públicos, el DTSC revisará y considerará cualquier comentario

revisiones necesarias al e su aprobación final.

correo un respuesta a los e han presentado un

ionado su nombre y dirección.

eproyecto RAW, es muy posible excavación comenzarán a

tividades de limpieza y o menos unas diez semanas,

y 5:00 p.m., de lunes a

tán transportando la tierra desde

camente las rutas e finalizar el

nducirá el estudio del suelo para confirmar que los objetivos de la limpieza han

la PG&E presentará un informe de la terminación de la acción de remoción al

C para su revisión y aprobación.

Dónde encontrar documentos del plan El DTSC le recomienda que usted revise el anteproyecto RAW, NOE, y otros documentos relacionados a éstos, disponibles en los repositorios de información indiciados a continuación:

Biblioteca pública de Watsonville 275 Main Street Suite 100 Watsonville, CA 95076 (831) 768-4300 Horas: Lunes – jueves, 9:30 am – 8:00 pm 4

proyremoción de la tierra excacamiones y llevada a unapermitida legalmente par

Próximos pasos AL finalizar el períod

público recibido y hará lasanteproyecto RAW antes dTambién, se enviará por comentarios a todos los qucomentario y ha proporc

Si se aprueba el antque las actividades de principios del 2012. Las acexcavación durarán por ly ocurrirán entre 7:00 a.m. viernes.

Los camiones que esy hasta el lugar, usarán úniaprobadas por la ciudad. Después dproceso de limpieza, se co

sido logrados y entonces

DTS

5

Department of Toxic Substances Control

rkeley, CA 94710

5:00 p.m. técnicos clave, hojas de

dad están del DTSC

Oficina Regional de Informes 700 Heinz Avenue, Be(510) 540-3800 Llame para hacer una cita Horas: Lunes – viernes, 8:00 a.m. – Copias de los informes

información, y otras relacionadas a la propietambién disponibles en línea en el sitio Web

Veronica Lopez-Villasenor, Especialista en la

ada gratuita (886) 495-5651 (oprimir el 5 e el 3) o (916) 255-3651 [email protected]

participación del público Llam

medios publicitarios,

cia Oficial de información al público del DTSC

Para preguntas sobre comuníquese con:

Jeanne Gar

(818)717-6573

:

www.envirostor.dtsc.ca.gov.

Todo documento puesto a la disposiciónpor parte del DTSC puede estar también en otros formatos (co

del públidisponibl

mo Braile, letra grande, etc) sponda,

Favor dpez-Villasen

ntactarse para obtener más información Si tiene alguna pregunta sobre el proyecto y las actividades de limpieza, contáctese con: Henry Chiu, Gerente de pro(510) 540-3759

co e o

e or

[email protected]

Aviso a las personPuede obtener inform

en cualquier otro idioma, según correconforme a las leyes estatales y federalesponerse en contacto con Veronica Lopara obtener ayuda.

Con quién co

as con sordera ación adicional sobre la

propiedad usando los servicios de California State Relay Service llamando al (888) 877-5378 (TDD). Pídales que se pongan en contacto con Veronica Lopez-Villasenor llamando al (916) 255-3651 respecto al proyecto.

yecto del DTSC

[email protected]

Resúmen de la limpieza propuesta

El DTSC está proponiendo un plan de limpieza de una porción de la antigua planta de mente a la PG&E.

proximadamente 25 ovidas del lugar; las áreas excavadas serán

amiento cubierto con

El trabajo de limpieza durará hasta 10 semanas.

Se usarán medidas de protección para la comunidad durante todo el proyecto, incluyendo, el control del polvo en el lugar y en la línea de la cerca, mojando la tierra para suprimir el polvo, cubriendo las pilas de tierras, dejando de trabajar en días ventosos, y otras.

El plan de limpieza está dispobible para el que el público lo revise y presente sus comentarios durante el 27 de Juno

gas manufacturado en Watsonville-1, perteneciente previa Bajo este plan, unas 300 yardas cúbicas de tierra y asfalto (a

camionadas) serán excavadas y remrellenadas con tierra limpia y se construirá un nuevo estacionasfalto.

, 2011 hasta el 31 de Julio, 2011.

Information Repositories: A copy of the draft RAW, the CEQA NOE and other site‐related

documents are available for public review at the information repositories listed below:

DTSC – File Room

700 Heinz Avenue

Berkeley, CA 94710

(510) 540‐3800

Call for appointment

Watsonville Public Library

275 Main Street, Suite 100

Watsonville, CA 95076

(831) 768‐3400

Dody Anderson, Principal Librarian

All public documents provided by DTSC can be made available in an alternate format (i.e.

Braille, large print, etc.) or in another language as appropriate, in accordance with state and

federal law. Please contact Veronica Lopez‐Villasenor for assistance as noted in the For More

Information section.

EnviroStor Database: Copies of key technical reports, fact sheets, and other site‐related

information are available online at DTSC’s EnviroStor website:

http://www.envirostor.dtsc.ca.gov.

For More Information:

For questions about the cleanup, please contact: Henry Chiu DTSC‐ Project Manager

[email protected]

(510) 540‐3759

For questions regarding the public participation process, please contact: Veronica Lopez‐Villasenor DTSC ‐ Public Participation Specialist [email protected] Toll‐Free (866) 495‐5651 or (916) 255‐3651 TTY/TDD Speech‐to‐Speech users may dial 711 for the California Relay Service For media inquiries, please contact: Jeanne Garcia DTSC ‐Public Information Officer [email protected] (818) 717‐6593

NOTICE OF PUBLIC COMMENT PERIOD FOR Draft Removal Action Workplan

Portion of the Former Watsonville‐1 Manufactured Gas Plant 618 Main Street, Watsonville, California

June 27 – July 31, 2011

The Department of Toxic Substances Control (DTSC) announces a 30‐day public comment

period on a draft Remedial Action Workplan (draft RAW) prepared by Pacific Gas and Electric

Company (PG&E) for a property located at 618 Main Street in downtown Watsonville,

California. This property (the site) was part of a larger parcel that a manufactured gas plant

(known as the former Watsonville‐1 MGP) operated on from the late 1800s to the early 1900s.

Environmental investigations found residues from the historic operations of the gas plant at the

site, including elevated levels of polycyclic aromatic hydrocarbons (PAHs), total petroleum

hydrocarbons (TPHs), and volatile organic compounds (VOCs) in soil, soil gas (air pockets in the

soil) and groundwater at the site. The draft RAW proposes a combination of cleanup activities

to include excavating about 300 cubic yards (up to 25 truckloads) of soil and asphalt and

replacing it with clean fill material, capping or paving some areas, ongoing monitoring of

groundwater and soil gas, and making changes to the deed restriction on the property to

require monitoring of site conditions and limiting what the property may be used for in the

future.

California Environmental Quality Act (CEQA): To comply with CEQA, DTSC has evaluated the

project to determine potential environmental impacts of the proposed cleanup plan. DTSC has

determined that the proposed cleanup plan is exempt from CEQA and would have no significant

impact to the environment or community. DTSC has documented this finding in a Notice of

Exemption (NOE) and intends to file it with the Governor’s Office of Planning and Research,

State Clearinghouse, if the draft RAW is approved.

Public Comment Period: The public is invited to comment on the draft RAW and CEQA NOE

during the 30‐day public comment period which runs from June 27, 2011 to July 31, 2011. All

public comments will be carefully considered in making the final decision for the site. Written

comments must be postmarked by July 31, 2011. Please mail your comments to Henry Chiu,

DTSC Project Manager, at 700 Heinz Avenue, Berkeley, California 94710, or email your

comments to him at [email protected].

Information Repositories: A copy of the draft RAW, the CEQA NOE and other site‐related

documents are available for public review at the information repositories listed below:

DTSC – File Room

700 Heinz Avenue

Berkeley, CA 94710

(510) 540‐3800

Call for appointment

Watsonville Public Library

275 Main Street, Suite 100

Watsonville, CA 95076

(831) 768‐3400

Dody Anderson, Principal Librarian

All public documents provided by DTSC can be made available in an alternate format (i.e.

Braille, large print, etc.) or in another language as appropriate, in accordance with state and

federal law. Please contact Veronica Lopez‐Villasenor for assistance as noted in the For More

Information section.

EnviroStor Database: Copies of key technical reports, fact sheets, and other site‐related

information are available online at DTSC’s EnviroStor website:

http://www.envirostor.dtsc.ca.gov.

For More Information:

For questions about the cleanup, please contact: Henry Chiu DTSC‐ Project Manager

[email protected]

(510) 540‐3759

For questions regarding the public participation process, please contact: Veronica Lopez‐Villasenor DTSC ‐ Public Participation Specialist [email protected] Toll‐Free (866) 495‐5651 or (916) 255‐3651 TTY/TDD Speech‐to‐Speech users may dial 711 for the California Relay Service For media inquiries, please contact: Jeanne Garcia DTSC ‐Public Information Officer [email protected] (818) 717‐6593



June 27 – July 31, 2011














future.















June 27 – July 31, 2011














future.













Removal

APPENDIX E

NOTICE OF EXEMPTION

State of California – California Environmental Protection Agency Department of Toxic Substances Control

___________________________________ CEQA Notice of Exemption Form for VCPs March 12, 2008 Office of Planning & Environmental Analysis

1

CALIFORNIA ENVIRONMENTAL QUALITY ACT NOTICE OF EXEMPTION

To: Office of Planning and Research

State Clearinghouse P.O. Box 3044 1400 Tenth St., Room 212 Sacramento, CA 95812-3044

From: Department of Toxic Substances Control Brownfields and Environmental Restoration Program 700 Heinz Avenue Berkeley, California 94710

Project Title: Former Watsonville-1 Manufactured Gas Plant Site Removal Action Workplan Project Location: The project is located at 618 Main Street, Watsonville, Santa Cruz County

Project Description: Approval of a Removal Action Workplan (RAW), by the Department of Toxic Substances Control (DTSC) pursuant to Health & Safety Code, Division 20, Chapter 6.8 as submitted in October 2011 and prepared by Terra Pacific Group on behalf of the Pacific Gas and Electric Company (PG&E). The RAW focuses on removal and replacement of near-surface planter soil and asphalt pavement; groundwater and soil gas monitoring and sampling with natural attenuation; and institutional controls. A land use covenant (LUC) was recorded in 2001 as an interim measure to limit the use of the Site until further evaluation could be performed and a final remedy selected. A new LUC will be recorded to replace the existing one to restrict the Site from sensitive uses and which will require that future disturbances of soil be done in accordance with a soil management plan approved by DTSC. The purpose of the project is to minimize potential future exposure of humans (property workers and visitors) to the chemicals of concern (COCs) that may be available for ingestion, inhalation, or dermal contact. Remedial activities are scheduled to commence in February 2012 and are expected to take approximately eight weeks to complete. The 0.4 acre project site is located at the intersection of East Fifth Street and Main Street, in the downtown area of the City of Watsonville, California. The Assessor Parcel Number (APN) is 018-151-26. The Former Watsonville-1 Manufactured Gas Plant (MGP) (the Site) was previously part of a larger parcel that was constructed in 1871 and ceased operations in 1905. From 1905 to 1931, the Site was used for various purposes including; a schoolhouse, automobile painting and trimming shop, automobile dealership, and auto repair shop. In 1931, Coast Counties Gas and Electric Company (CCG&E) constructed the existing restaurant building for a customer service center. The northeastern end of the property where gas manufacturing had been conducted was sold to private parties in 1935. CCG&E continued to use the remaining portion of the property (the Site) as a customer service center until it was sold to PG&E in 1954. PG&E used the Site as a customer service center until 1989, when it leased the property for use as a restaurant. The Site is currently privately owned and occupied by Jalisco’s, a Mexican restaurant. The Site is bordered by a bank to the northwest, a commercial property to the northeast, a market to the southeast, and Main Street to the southwest. Residential properties exist approximately 100 feet north of the Site.

Several environmental investigations were conducted at the Site since 1985. These investigations have indicated that soil, soil gas and groundwater are impacted by MGP residual wastes. The maximum concentrations of COCs in soil at up to 20 feet below ground surface are benzo(a)pyrene (B(a)P) at 21 milligrams per kilogram (mg/kg); naphthalene at 320 mg/kg; total petroleum hydrocarbons (TPH) as gasoline at 5,300 mg/kg, TPH-diesel at 14,000 mg/kg and TPH-motor oil at 9,500 mg/kg. The maximum concentrations of COCs in soil gas are benzene at 43.7 micrograms per liter (ug/L), ethylbenzene at 309 ug/L, toluene at 1,320 ug/L, xylenes at 2,170 ug/L, and naphthalene at 85.8 ug/L. The maximum concentrations of COCs in groundwater are naphthalene at 580 ug/L, benzene at 140 ug/L, TPH-gasoline at 4,200 ug/L, TPH-diesel at 6,500 ug/L, and TPH-motor oil at 1,200 ug/L. Specific environmental safeguards and monitoring procedures that are enforceable and conditional for project approval are included in the RAW, as to ensure that impacts to the environment will be less than significant.



2

The RAW includes a Sampling and Analysis Plan, Waste Management Plan, Quality Assurance Project Plan, and Transportation Plan. A detailed Health and Safety Plan that meets the requirements of California Code of Regulation title 8, section 5192 will be prepared prior to implementation of the project. The implementation of the excavation shall comply with Cal/OSHA regulations and the California Code of Regulations. In addition, in the event resources of biological, cultural, or historical significance are found in the course of project activities, work will be suspended while a qualified biological, cultural, or historical resources specialist makes an assessment of the area, and arrangements are made to protect or preserve any resources that are located. If human remains are discovered at the Site, no further disturbance will occur in the location where the remains are found, and the County Coroner will be notified pursuant to Health and Safety Code section 7050.5. The Coroner will determine disposition within 48-hours (Public Resources Code, section 5097.98). The restaurant building, originally constructed in 1931 for use as a customer service center, is listed on the City of Watsonville’s Directory of Historical Resources and is deemed eligible for listing on the National Register of Historic Places (NRHP). The restaurant building will not be disturbed during the remediation activities. A Transportation Plan is part of the RAW which includes, among other things, use only pre-planned and authorized routes, as approved by the City of Watsonville. Approximately 300 cubic yard of asphalt and impacted soil will be excavated and trucked for offsite disposal, which would require approximately 350 truck trips for both excavated and imported fill soils. The current truck route from the Site will be as follows: Trucks transporting soil to the permitted off-site disposal facility are expected to leave the Site from Main Street (CA-152) then onto CA-1 North, CA-17 North, I-880 North, CA-262 East, I-680 North, I-580 East, I-205 East, I-5 North, Roth Road exit, left onto South Airport Way, right onto French Camp Road, left onto South Austin Road. The anticipated final disposal is at Forward Landfill in Manteca, California.

An analysis of the potential effects of project activities upon existing environmental conditions indicates that implementation of environmental safeguards and monitoring procedures that are enforceable and made a condition of project approval will ensure that impacts to the environment will be less than significant. As a result, DTSC finds that the project is exempt from further environmental review under CEQA. Name of Public Agency Approving Project: California Environmental Protection Agency, Department of Toxic Substances Control Name of Person or Agency Carrying Out Project: Pacific Gas & Electric Company (Terra Pacific Group is the environmental consultant) Exemption Status:

Class 30 Categorical Exemption: Cal. Code Regs., tit. 14, §15330 General Rule: Cal. Code Regs., tit. 14, §15061(b)(3)

Reasons Why Project is Exempt: DTSC has determined that the project is a Class 30 categorical exemption project (as provided in California Code of Regulations, title 14, sections 15300.2 and 15330) and is, therefore, exempt from the provisions of California Environmental Quality Act (CEQA) and the Guidelines for the following reasons: 1. The project is a cleanup action to be taken to prevent, minimize, stabilize, mitigate, or eliminate the release

or threat of release of a hazardous waste or substance. 2. The project is a removal action costing $1 million or less. 3. The project will not be located on a site which is included on any list compiled pursuant to Cal. Gov. Code §

65962.5 (http://calepa.ca.gov/sitecleanup/corteselist/default.htm) 4. The project will not have a significant effect on the environment due to unusual circumstances.



3

5. The project will not result in damage to scenic resources, including but not limited to, trees, historic buildings, rock outcroppings, or similar resources, within a highway officially designated as a state scenic highway.

6. The project will not cause a substantial adverse change in the significance of a historical resource. 7. The project will not require onsite use of a hazardous waste incinerator or thermal treatment unit. 8. The project will not require the relocation of residences or businesses. 9. The project will not involve the potential release into the air of volatile organic compounds as defined in

Health and safety Code section 25123.6 10. The cumulative impact of successive projects of the same type on the same place, over time, if there are

any, will not be significant. 11. The project will be consistent with applicable State and local environmental permitting requirements

including, but not limited to: (a) offsite disposal; (b) water quality standards, e.g., waste discharge requirements or storm water discharge requirements issued by the State Water Resources Control Board or an appropriate Regional Water Quality Control Board; (c) air quality rules such as those governing volatile organic compounds; and (d) Occupational Safety and Health Administration health and safety requirements; and approved by the regulatory body with jurisdiction over the Site.

12. All fieldwork will be conducted according to a site-specific Health and Safety Plan prepared in accordance with Title 8, California Code of Regulations, section 5192, and only properly trained personnel will conduct the work.

13. Natural attenuation is the recommended alternative for groundwater, therefore the project will not impact groundwater.

14. The project is anticipated to be of short duration, lasting approximately 8 weeks. 15. The Site is entirely paved; therefore, no biological resources are present at the Site. 16. According to the City of Watsonville Historic Districts and Neighborhood Conservations Districts Maps, the

Site does not lie within the historical zone; however, the restaurant building is designated as a historical building but will not be affected by the remediation.

17. Approximately 300 cubic yard of asphalt and impacted soil will be excavated for disposal which will require approximately 350 truck trips for both excavated and imported fill soils. A Transportation Plan is part of the RAW. Transportation of impacted soil will occur on specified truck routes that will be determined by the City of Watsonville as part of approving the grading permit, minimizing any potential impact on the local neighborhood.

18. Throughout the duration of the project the work area will be fenced to protect public safety. Because the cleanup project will only require the removal of the top 2 feet of soil in landscape planter areas, shoring for the excavation will not be required for the project; however, should shoring be necessary during implementation, procedures will follow the Cal/OSHA requirements shoring.

19. Project activities will be performed between the hours of 7:00 am and 5:00 pm.

Gas and power company for California - FINAL …...FINAL REMOVAL ACTION WORKPLAN Former...

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