2019 GROUNDWATER MONITORING REPORT ......term-monitoring data-quality objectives, reduce sampling...

2019 GROUNDWATER MONITORING REPORT LOCKHEED MARTIN CORPORATION

MIDDLE RIVER COMPLEX 2323 EASTERN BOULEVARD MIDDLE RIVER, MARYLAND

Prepared for: Lockheed Martin Corporation

Prepared by: AECOM Technical Services, Inc.

November 2019

Approved by: Lockheed Martin, Inc.

Revision: 0

Matthew Panciera, PE, LEP Project Manager

Holly Brown, MS, PG, STS Deputy Project Manager

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TABLE OF CONTENTS Section Page Table of Contents ........................................................................................................... i List of Figures .............................................................................................................. iv List of Tables ................................................................................................................ iv Appendices ................................................................................................................... iv Executive Summary ................................................................................................ ES-1 Section 1 Introduction and overview ........................................................................ 1-1 Section 2 Site Background ........................................................................................ 2-1

2.1 Middle River Complex Background .............................................................. 2-1 2.1.1 Middle River Complex History ................................................................. 2-1 2.1.2 Middle River Complex Characteristics .................................................... 2-2

2.1.2.1 Current and Surrounding Land Use ................................................ 2-2 2.1.2.2 Physiography .................................................................................. 2-2 2.1.2.3 Hydrology ....................................................................................... 2-2 2.1.2.4 Soils ................................................................................................ 2-3 2.1.2.5 Regional Geology ........................................................................... 2-3 2.1.2.6 Regional Hydrogeology .................................................................. 2-3 2.1.2.7 Middle River Complex Geology ...................................................... 2-4 2.1.2.8 Middle River Complex Surficial Aquifer Hydrogeology .................... 2-5

2.2 Groundwater ................................................................................................ 2-5 2.2.1 Groundwater Studies and Remedy ......................................................... 2-6

2.2.1.1 Groundwater Background ............................................................... 2-6 2.2.1.2 Off-site and Deep Well Groundwater Monitoring ............................ 2-7 2.2.1.3 On-site Groundwater Response Action and Monitoring .................. 2-7

2.2.2 Groundwater Monitoring Optimization Program .................................... 2-10 Section 3 Investigation Approach and Methodology .............................................. 3-1

3.1 Synoptic Groundwater Level Measurements ................................................ 3-1 3.2 Groundwater Sampling and Chemical Analysis ........................................... 3-2

3.2.1 Well Purging ........................................................................................... 3-2 3.2.2 Sample Collection and Preservation ....................................................... 3-3

3.3 Laboratory Analyses .................................................................................... 3-3 3.4 Documentation ............................................................................................. 3-4

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3.5 Equipment Decontamination ........................................................................ 3-4 3.6 Waste Management ..................................................................................... 3-4 3.7 Data Management ........................................................................................ 3-5

3.7.1 Data Tracking and Control ...................................................................... 3-5 3.7.2 Data Export to EESH Geographic Information System ........................... 3-6 3.7.3 Mobile Data Collection ............................................................................ 3-6

3.8 Data Validation ............................................................................................. 3-7 3.9 Sustainability Approach ................................................................................ 3-8

Section 4 Groundwater Monitoring Results ............................................................. 4-1 4.1 Groundwater Elevation Data ........................................................................ 4-1 4.2 Groundwater Analytical Results ................................................................... 4-2

4.2.1 Shallow Groundwater Analytical Results ................................................ 4-2 4.2.1.1 Volatile Organic Compounds .......................................................... 4-2 4.2.1.2 1,4-Dioxane .................................................................................... 4-4 4.2.1.3 Benzene, Toluene, Ethylbenzene, Xylenes, and Common Fuel Constituents ................................................................................................. 4-5 4.2.1.4 Metals ............................................................................................. 4-6 4.2.1.5 Polychlorinated Biphenyls and Chlorobenzenes ............................. 4-6

4.2.2 Intermediate Groundwater Analytical Results ......................................... 4-7 4.2.2.1 Volatile Organic Compounds .......................................................... 4-7 4.2.2.2 1,4-Dioxane .................................................................................... 4-9 4.2.2.3 Benzene, Toluene, Ethylbenzene, Xylenes, and Common Fuel Constituents ............................................................................................... 4-10 4.2.2.4 Metals ........................................................................................... 4-10 4.2.2.5 Polychlorinated Biphenyls and Chlorobenzenes ........................... 4-11

4.2.3 Deep Groundwater Analytical Results .................................................. 4-12 4.2.4 Off-site Groundwater Analytical Results ............................................... 4-12 4.2.5 Monitored Natural Attenuation Parameters ........................................... 4-13

4.2.5.1 Blocks E and F ............................................................................. 4-14 4.2.5.2 Block G ......................................................................................... 4-14 4.2.5.3 Block I ........................................................................................... 4-14

4.2.6 Trichloroethene Plume Areas and Volatile Organic Compound Trends 4-15 4.2.6.1 Blocks E and F Southeastern Plume ............................................ 4-15 4.2.6.2 Block G Plume .............................................................................. 4-16

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4.2.6.3 Block I West of Building A Plume ................................................. 4-17 4.2.6.4 Block I South of Building C Plume ................................................ 4-19 4.2.6.5 Block I South of Building C Plume ................................................ 4-20

Section 5 Summary and Conclusions ...................................................................... 5-1 5.1 Groundwater Elevations ............................................................................... 5-1 5.2 Work plan variations ..................................................................................... 5-1 5.3 Grounwater quality trends and findings ........................................................ 5-2 5.4 Recommendations ....................................................................................... 5-6

Section 6 References ................................................................................................. 6-1

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TABLE OF CONTENTS (CONTINUED)

LIST OF FIGURES Figure 1 Middle River Complex Location Map Figure 2 Site Layout and Tax Blocks Middle River Complex Figure 3 Groundwater Well Sampling Network—April 2019 Figure 4 Potentiometric Surface Elevation, Shallow Monitoring Wells—March 2019 Figure 5 Potentiometric Surface Elevation, Intermediate Monitoring Wells—March 2019 Figure 6 1,4-Dioxane in Shallow Monitoring Wells—April 2019 Figure 7 Total BTEX in Shallow Monitoring Wells—April 2019 Figure 8 1,4-Dioxane in Intermediate Monitoring Wells—April 2019 Figure 9 Total BTEX in Intermediate Monitoring Wells—April 2019 Figure 10 TCE in Shallow Monitoring Wells—April 2019 Figure 11 TCE in Intermediate Monitoring Wells—April 2019

LIST OF TABLES Table 1 2019 Monitoring Well Network, Chemical Analyses and Methods Performed Table 2 Monitoring Well Purge Completion Criteria Table 3 Quality Assurance Sampling Table 4 March 2019 Synoptic Groundwater Level Measurements Table 5 April 2019 Groundwater Sampling Event Detections—All Analyses

APPENDICES Appendix A—2019 Monitoring Well Repair Report Appendix B—Daily Field Reports and Low-Flow Sampling Forms Appendix C—Investigative Derived Waste Documentation Appendix D—Data Validation Report Appendix E—2019 Groundwater Analytical Results Appendix F—Laboratory Analytical Reports Appendix G—Chlorinated Ethene Time-Series Trend Charts

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ACRONYMS AND ABBREVIATIONS 1,1-DCE 1,1-dichloroethene

1,2-DCA 1,2-dichloroethane

1,2,4-TCB 1,2,4-trichlorobenzene

1,3-DCB 1,3-dichlorobenzene

1,4-DCB 1,4-dichlorobenzene

AECOM AECOM Technical Services, Inc.

BTEX benzene, toluene, ethylbenzene, xylenes

cis-1,2-DCE cis-1,2-Dichloroethene

COC(s) chain(s) of custody

DCB dichlorobenzene

DFR daily field report

DO dissolved oxygen

F001 Plume hazardous F001 TCE groundwater plume

GIS geographic information system

LFSP low-flow sampling procedure

Lockheed Martin Lockheed Martin Corporation

LTM laboratory task manager

MDE Maryland Department of the Environment

MEE methane, ethane, ethene

mg/L milligrams per liter

MRC Middle River Complex

msl mean sea level

MTBE methyl tert-butyl ether

MW monitoring well

NAA natural attenuation assessment

NFA No Further Action

ORP oxidation-reduction potential

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PCB(s) polychlorinated biphenyl(s)

PCE tetrachloroethene

PID Photoionization Detector

PPE personal protective equipment

PVC polyvinyl chloride

TCE trichloroethene

Tetra Tech Tetra Tech, Inc.

Tilley Tilley Chemical Company

TOC total organic carbon

USEPA United States Environmental Protection Agency

USDOT United States Department of Transportation

UST underground storage tank

VC vinyl chloride

VISLs vapor intrusion screening levels

VOC(s) volatile organic compound

µg/L microgram(s) per liter

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EXECUTIVE SUMMARY

On behalf of Lockheed Martin Corporation, AECOM Technical Services, Inc., has prepared this

groundwater monitoring report for the April 2019 groundwater sampling at the Middle River

Complex in Middle River, Maryland. �is report is part of the long-term groundwater and surface

water monitoring program at the Middle River Complex, conducted in accordance with the

approved 2018-2020 Groundwater and Surface Water Monitoring Work Plan and its associated

addenda (AECOM Technical Services, Inc., 2017a, 2018a, 2018b, 2019). Groundwater was

sampled from April 1 to 23, 2019.

As noted in Sections 3.1 and 3.7.3, variations to the approved 2018-2020 Groundwater and

Surface Water Work Plan and its associated addenda (AECOM Technical Services, Inc., 2017a,

2018a, 2018b, 2019) occurred. Primarily:

• MRC-MW95D and MRC-MW96D were not gauged or sampled due to the wells being damaged and destroyed, respectively. �ese wells were installed in 2010 to monitor deep groundwater beneath the surficial aquifer at the Middle River Complex. �ese wells are sampled every three years to confirm that Middle River Complex groundwater constituents have not migrated through the clay confining layers underlying the surficial aquifer to more permeable materials below the clay aquitard. �e data objective of these wells was to monitor groundwater quality in sandy materials at depths ranging from 189 to 214 feet below ground surface. �e project team is evaluating whether MRC-MW95D and MRC-MW96 should be formally abandoned or replaced.

• During the April 2019 groundwater sampling event, AECOM Technical Services, Inc.’s Portal for ArcGIS experienced a major crash. This crash effected data completeness and triggered a corrective action for future sampling events. Geochemical purge completion parameters could not be recovered for six of the wells sampled as part of the 2019 sampling event (MRC-MW27B, MRC-MW94D, MRC-MW101A, MRC-MW101B, MRC-MW102A, and MRC-MW130A). Analytical data for the above list of wells is present but the wells are missing geochemical purge completion parameters. Changes to mobile data app collection procedures and corrective actions for future sampling are as follows:

• Use of ArcGIS Online instead of Portal. There have been no stability issues with ArcGIS Online.

• All field personnel that will be using Survey123 will submit a test record to ensure that they have the correct form version and are not having synchronization issues with their device at least one week prior to mobilization.


• Include metadata in the sample form that records date and time submitted and a device identification; this assists in troubleshooting synchronization issues.

• Never delete project forms or data from field tablets. The Survey123 app will store all form data on each device after submitting. If an old version of a form is removed from a device, all data stored on that device associated with that form will also be deleted.

• Daily quality control checks will be conducted by both the database manager in the office and the field team lead who is tracking which wells have been sampled. In addition, paper forms will be on hand if there is a malfunction with a tablet or Survey123.

• Screen shots will be taken by the filed staff of parameters that are sampled from each well and will be saved to the individual tablet in the event of a Survey123 malfunction.

The findings of the April 2019 groundwater sampling analyses and groundwater level

measurements for the Lockheed Martin Corporation Middle River Complex are summarized as

follows:

• Synoptic groundwater measurements obtained in March 2019 are consistent with previously observed groundwater elevations and observed radial groundwater flow pathways to Dark Head Cove and Cow Pen Creek.

Blocks E and F Southeastern Trichloroethene Plume

• �e Blocks E and F Southeastern Trichloroethene Plume undergoes some degradation of parent material into daughter products but remains largely stable. �e distribution of trichloroethene downgradient from the former source area Underground Storage Tank #2 indicates that the narrow plume is migrating from Block E and likely discharging into Dark Head Cove and/or possibly migrating beneath the surface water body. Surface water results indicate that trichloroethene concentrations are below all screening levels. A mass discharge assessment is currently being performed to address data objectives in the context of the remedial action. �e presence of elevated cis-1,2-dichloroethene concentrations in downgradient intermediate wells MRC-SEMW-8I (2,030 micrograms per liter [µg/L]) and MRC-EW-1 (1,660 µg/L) indicates that partial trichloroethene degradation is occurring within the intermediate aquifer downgradient from the Underground Storage Tank #2 source area. In addition, elevated trichloroethene concentrations upgradient of the former source area Underground Storage Tank #2 possibly represent downstream migration of the Block I South of Building C Plume.

Blocks E and F Chlorobenzene Plumes

• In addition to the presence of trichloroethene, the Blocks E and F Chlorobenzene Plumes contain 1,2,4-trichlorobenzene and related chlorobenzene compounds that are associated


with polychlorinated biphenyl transformer fluid for use in former transformers. Elevated 1,2,4-trichlorobenzene concentrations were detected in Block E groundwater and soil during previous volatile organic compound sampling and are thought to be associated with the release of polychlorinated biphenyls from former transformers in Block E. The analytical results from the initial sampling of newly installed monitoring wells in Blocks E and F revealed that chlorobenzene compounds were present in groundwater in southeastern and southwestern Blocks E and F. Specifically, chlorobenzene was detected at MRC-MW126A (located downgradient of Transformer Room #4) at a concentration of 37 µg/L, while 1,2,4-trichlorobenzene was detected at MRC-MW130A (south of Transformer Room #3) at a concentration of 150 µg/L. Additional site investigation has commenced to characterize chlorobenzene contamination and related detections in Blocks E and F.

Block G Plume

• In the Block G Plume, trichloroethene detections at upgradient well MRC-MW21B and wells located near the Tilley Chemical Company building remain stable. A-Zone wells (MRC-MW21A, MRC-MW98A, and MRC-MW111A) designated to evaluate potential for vapor intrusion within the Tilley Chemical Company building observed groundwater concentrations below vapor intrusion screening levels. In 14 rounds of vapor intrusion monitoring, it was confirmed that the A-Zone groundwater contaminant concentrations did not result in vapor intrusion.

• Relatively low concentrations of trichloroethene degradation products were detected in wells near the Tilley Chemical Company building, suggesting little to no degradation of the plume is occurring as it migrates downgradient deep below the Tilley Chemical Company building. Downgradient well MRC-MW14B and nearby wells in southern Block G exhibit no exceedances for trichloroethene, indicating that a reductive environment is still present as a result of the injections performed in this area of Block G and confirming that the injections performed in Block G were effective in exceeding contaminant reduction goals. Results of performance sampling within the treatment area, including verification monitoring in 2017 and 2018, were detailed in the Remedial Action Completion Report for Groundwater at Block G (Tetra Tech Inc., 2018). In the report, Lockheed Martin Corporation recommended No Further Action in the Block G groundwater treatment area; the Maryland Department of the Environment provided approval for No Further Action in April 2019.

• The Block G 1,4-dioxane plume contains higher contaminant concentration levels at monitoring well (MRC-MW12A) along the shoreline and may indicate possible flow into surface water at Cow Pen Creek. In general, intermediate aquifer wells display higher concentrations of 1,4-dioxane indicating that the plume is migrating downward. Ongoing surface water monitoring of Cow Pen Creek has not detected 1,4-dioxane at concentrations above risk-based swimming screening levels; surface water results will be provided under separate cover.

Block I West of Building A Plume

• �e Block I West of Building A Plume exhibits high cis-1,2-dichloroethene concentrations detected in MRC-MW96A (28,600 µg/L), which may indicate that original source material


is already degrading. However, several intermediate wells close in proximity to both the shallow and intermediate-aquifer maximum concentrations indicate that some downward and lateral migration to the west and south has occurred.

• �e Block I West of Building A Plume, though stable to decreasing in most upgradient wells, is stable towards downgradient wells, particularly in the intermediate aquifer (MRC-MW120B). A deeper western groundwater investigation was performed in 2018 to further delineate the plume and refine the conceptual site model. Results of this investigation sought to determine if additional deeper groundwater wells were needed to fully assess the downgradient groundwater flow pathway toward Cow Pen Creek. During the investigation, the installation of deeper downgradient monitoring wells (MW132C and MW133B) occurred and low trichloroethene detections were detected in each well. These wells are screened within distinct, intermittent permeable layers beneath the thick clay unit, referred to as the lower high-permeable zone. Distinct upper and lower permeable zones, separated by a thick clay layer, are present throughout most of the localized region west of Building A, and extend toward Cow Pen Creek. Based on lithology and lack of detectable concentrations of trichloroethene collected in the direct-push exploratory borings, no additional deep monitoring wells were installed. The results indicate that the study successfully delineated the downgradient extent of the plume (Tetra Tech Inc., 2019).

• Benzene, toluene, ethylbenzene, and xylene concentrations are stable to decreasing over time in the Block I West of Building A Plume, apart from a likely historic release under Building A. Trichloroethene detected in the shallow aquifer at MRC-MW17A, has increased an order of magnitude from 2018 (295.5 µg/L) to 2019 (2,116 µg/L). This increase will be monitored over time and MRC-MW17A will be included in the 2020 groundwater monitoring program. Benzene, toluene, ethylbenzene, and xylene concentrations in the intermediate aquifer are stable to decreasing over time.

• 1,4-Dioxane concentrations exceeding groundwater standards are primarily detected in the lower permeable zone within the Block I West of Building A Plume. Several downgradient wells indicate that the plume is migrating west and south from the area west of Building A toward Cow Pen Creek. Ongoing surface water monitoring of Cow Pen Creek has not detected 1,4-dioxane at concentrations above risk-based swimming screening levels; surface water results will be provided under separate cover.

Block I South of Building C Plume

• Overall, the Block I South of Building C Plume is stable to slightly increasing over time and may connect with the Blocks E and F Southeastern Plume as it migrates east and south from the potential source area located under Building C or just south of Building C (near MRC-MW60A and MRC-MW60B). Increasing trichloroethene trends observed in some monitoring wells directly downgradient of Block I Building C may be caused by the following:

• a continued release from an unidentified source(s) beneath Building C; • releases from source material that has sorbed onto finer-grained materials and is

back-diffusing into groundwater and providing a continuing source of contamination in the area; and/or


• Plume remediation-related injections that may have moved the contaminant mass within the subsurface.

• An increase in cis-1,2-dichloroethene concentrations within the Block I South of Building C Plume indicates anaerobic reductive dechlorination is occurring primarily in the shallow aquifer. Overall, a 70-percent reduction in trichloroethene mass in the active remediation areas continues to be achieved. �e Block I South of Building C Plume source treatment area has received three injection events from March 2015 to September 2017. �ese events were effective in meeting the contaminant reduction goals in the treatment area. Results of performance sampling within the treatment area, including verification monitoring in 2018 and 2019, are detailed in the Remedial Action Completion Report for Groundwater at Block I (Tetra Tech Inc., 2019). In the report, Lockheed Martin Corporation recommended No Further Action in the Block I groundwater treatment area.

• In both the shallow and intermediate aquifers, historic high trichloroethene concentrations were detected during the 2019 annual groundwater monitoring event within the footprint of the Block I South of Building C Plume at MRC-MW60A (2,070 µg/L) and MRC-MW60B (9,330 µg/L). In addition, nearby well MRC-MW81B and downgradient well MRC-MW102B also show concentrations of cis-1,2-dichloroethene above Maryland Department of the Environmental groundwater standards. This spread of trichloroethene and cis-1,2-dichloroethene suggests either the plume could be sourcing parent material at a relatively same rate as it is reducing and/or injections moved the contaminant mass within the subsurface. Post injection monitoring continues to be performed to confirm the response action performance goal of reducing trichloroethene mass by 70-percent in active remediation areas is maintained.

• Trichloroethene detections in downgradient wells MRC-MW27A (73.4 µg/L), MRC-MW26A (22.3 µg/L, a historic high concentration), and MRC-MW29A (2.1µg/L) indicate that the plume may be migrating from south of Building C within the shallow aquifer toward Block E. The distribution of trichloroethene in the intermediate aquifer is also consistent with plume migration towards Block E. High concentrations of cis-1,2-dichloroethene in downgradient wells in northern Block E (i.e., MRC-MW79B [563 µg/L]) may indicate that the plume is degrading before it migrates far from the source area due to bioremediation efforts upgradient, just south of Building C. However, increased elevated trichloroethene concentrations at MRC-MW27B (646 µg/L) and (MRC-MW79B (739 µg/L), located within the historical footprint of the plume, may be an indication of migration of the trichloroethene plume that originates from Building C. Both MRC-MW27B and MRC-MW79B are hydraulically downgradient from the presumed source area wells.

• A separate occurrence of slightly elevated trichloroethene occurs at MRC-MW25A (154 µg/L) that indicates either an alternate flow path from the source area south of Building C or a smaller isolated plume. An alternate flow path could be inferred from the groundwater contour map for the shallow aquifer. Slightly elevated trichloroethene concentrations are also observed in intermediate well MRC-MW87B (23.2 µg/L), with no clear relationship to the Block I South of Building C Plume.


Block I East of Building C Plume

• An additional trichloroethene plumelet associated with MRC-MW88A in Block I East of Building C, is stable over time with a concentration of 1,030 µg/L in 2019. This isolated plume indicates a potential additional source under Building C. Migration of trichloroethene impacted groundwater was not observed at down-side gradient shallow monitoring wells MRC-MW116A and MRC-MW77A, or in intermediate monitoring wells MRC-MW88B and MRC-MW95B in the vicinity of MRC-MW88A.

Review of on-going work to characterize the plumes in Blocks E and F will also be performed to

identify recommendations to the groundwater monitoring program. Recommendations for future

remediation activities based on the results of the April 2019 groundwater sampling include:

• Continue annual groundwater monitoring in April 2020 as part of the Middle River Complex surface water and groundwater monitoring program.

• Evaluate and optimize the sampling program within the existing well network and the possible refinement of the number of wells sampled based on trends observed in chemical data, together with results of the plume stability analysis, to better define contaminant plume areas.

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SECTION 1 INTRODUCTION AND OVERVIEW

On behalf of Lockheed Martin Corporation, AECOM Technical Services, Inc., has prepared this

2019 groundwater monitoring report summarizing the April 2019 groundwater sampling at the

Middle River Complex in Middle River, Maryland. Figure 1 shows the location of the Middle River

Complex. �is report presents the current round of synoptic groundwater levels and analytical data

for selected monitoring wells as part of the long-term groundwater and surface monitoring program

at the Middle River Complex. �is report summarizes the investigative activities and results of the

April 2019 groundwater sampling, including:

• measuring synoptic groundwater levels

• monitoring well inspections and performing repairs as necessary

• managing investigation derived waste

�e objectives of the monitoring program are to:

• provide a current round of groundwater level and chemical data for selected wells

• better understand the nature and extent of chemical contamination in groundwater

• evaluate trends of on-site groundwater chemical plumes

• provide supplementary site-wide groundwater analysis in support of the ongoing groundwater remedy in Blocks E, F, G, and I

• provide supplementary site-wide groundwater analysis in support of ongoing site characterization west of Building A in Blocks I and H, and chlorobenzene characterization in the western portion of Blocks E and F

• provide A-level (shallow) well groundwater analysis near the Tilley Chemical Company, Inc. building to determine if chemical contamination could lead to vapor intrusion

• evaluate natural attenuation of the chemicals of concern in groundwater at the Middle River Complex


• inspect each accessible monitoring well, then conduct monitoring well repairs to preserve well integrity (presented in Appendix A).

�is report is organized into the following sections:

Section 1—Introduction: Presents the site objectives for the groundwater monitoring program.

Section 2—Site Background: Briefly describes site history, subsurface conditions, and

previous investigations.

Section 3—Investigation Approach and Methodology: Presents the technical approaches to

field activities and data management and describes the field methodologies employed.

Section 4—Groundwater Monitoring Results: Presents investigation results, interpretation,

and data-quality review.

Section 5—Summary and Conclusions: Summarizes the results of the current round of

sampling and provides recommendations for future activities.

Section 6—References: Cites references used to compile this report.

Figures, tables, and appendices are provided as stand-alone sections following Section 6.


SECTION 2 SITE BACKGROUND

2.1 MIDDLE RIVER COMPLEX BACKGROUND

The Middle River Complex is part of the Chesapeake Industrial Park, at 2323 Eastern Boulevard

in Middle River, Maryland, approximately 11.5 miles northeast of downtown Baltimore. It

consists of approximately 161 acres, including 12 main buildings, an active industrial area and

yard, perimeter parking lots, an athletic field, a vacant concrete lot, a trailer and parts storage lot,

and numerous grassy spaces along its perimeter. It is bounded by Eastern Boulevard (Route 150)

to the north, Martin State Airport to the east, Dark Head Cove to the south, and Cow Pen Creek to

the west. Figure 2 is a map showing the Middle River Complex layout.

LMC Properties, Inc., owns the Middle River Complex. Its primary activities at the Middle River

Complex include facility and building management and maintenance. The main site tenant is

MRA Systems, LLC, who’s ownership transferred to Vision Technologies Aerospace

Incorporated (United States subsidiary of Singapore Technologies Engineering Ltd.) in April

2019 during this sampling event. MRA Systems, LLC designs, manufactures, fabricates, tests,

overhauls, repairs, and maintains aeronautical structures, parts, and components for military and

commercial applications. Lockheed Martin Rotary and Mission Systems (a division of Lockheed

Martin Corporation) also conducts engineering activities and fabricates, assembles, tests, and

otherwise supports vertical launch systems at the Middle River Complex.

2.1.1 Middle River Complex History

In 1929, the Glenn L. Martin Company (a predecessor entity of Lockheed Martin Corporation)

acquired large parcels of undeveloped land in Middle River, Maryland, to manufacture aircraft for

United States government and commercial clients. In the early 1960s, Glenn L. Martin Company

merged with American-Marietta Company to form Martin Marietta Corporation. Around 1975, the

adjacent eastern airport area (currently Martin State Airport), approximately 750 acres, was

transferred to the State of Maryland. In the mid-1990s, Martin Marietta Corporation merged with

Lockheed Corporation to form Lockheed Martin Corporation. Shortly after the merger, General


Electric Company entities acquired most of Lockheed Martin Corporation’s aeronautical business

in Middle River and the General Electric subsidiary, MRA Systems, LLC., began operations at the

site. MRA Systems, LLC, was sold to Vision Technologies Aerospace Incorporated (United States

subsidiary of Singapore Technologies Engineering Ltd.) in April 2019.

2.1.2 Middle River Complex Characteristics

2.1.2.1 Current and Surrounding Land Use

The Middle River Complex is an industrial facility surrounded primarily by commercial,

industrial, and residential establishments. Six facilities adjacent to the Middle River Complex

make up the remaining portion of the Chesapeake Industrial Park. These include Tilley Chemical

Company, Inc. (a food and pharmaceutical-chemical distributor), North American Electric, Inc.

(an industrial and commercial electrical contractor), Johnson and Towers (a heavy-duty

automotive and boat repair and maintenance company), Ashley Furniture (a furniture warehouse

distributor), Exxon (a gasoline filling station and convenience store), and the Middle River Post

Office. Residential developments are on the opposite shores of Cow Pen Creek, Dark Head Cove,

Dark Head Creek, and north of Eastern Boulevard (Route 150).

2.1.2.2 Physiography

The Middle River Complex is in the Western Shore of the Coastal Plain physiographic province,

which is generally characterized by low relief. The Middle River Complex’s topography slopes

gently, ranging from sea level to 32 feet above mean sea level (Cassell, 1977). The topography

slopes from Eastern Boulevard to the southwest and south toward Cow Pen Creek and Dark Head

Cove.

2.1.2.3 Hydrology

The Middle River Complex is at the junction of Cow Pen Creek and Dark Head Cove. Both surface

water bodies discharge into Dark Head Creek, a tributary of Middle River, which is a tributary of

Chesapeake Bay. The Middle River Complex is approximately 3.24 miles (17,100 feet) upstream

of Chesapeake Bay. The Middle River Complex has no surface water bodies on site.

Surface-water runoff discharges from the facility via storm drains, except for areas immediately

adjacent to Cow Pen Creek and Dark Head Cove.


2.1.2.4 Soils

Soils underlying Middle River Complex have been mapped by the United States Department of

Agriculture Soil Conservation Service as Mattapex-Urban Land Complex and Sassafras-Urban

Land Complex (United States Department of Agriculture, 1993). Mattapex-Urban Land soils

consist of deep, well-drained, silty soils. Sassafras-Urban Land soils consist of deep, well-drained

sandy soils. In both complexes, the original soil textures have been disturbed, graded over, or

otherwise altered. Site characterization studies indicate that fine-grained (e.g., silt, clay), low-

permeability soils with interbedded sand layers make up most soils at the Middle River Complex.

2.1.2.5 Regional Geology

Geologic mapping of Baltimore County shows that the Middle River Complex is underlain by the

Potomac Group, a Cretaceous-age interbedded gravel, sand, silt, and clay unit ranging up to

800 feet thick. The Potomac Group is composed of three units: the Raritan and Patapsco

Formations, the Arundel Clay, and the Patuxent Formation. The Raritan and Patapsco Formations

range up to 400 feet thick and are composed of gray, brown, and red variegated silt and clay with

lenses of sand and gravel. The Arundel Clay ranges from 25 to 200 feet thick and is composed of

dark gray and maroon lignitic clays. The Patuxent Formation ranges up to 250 feet thick and is

described as a white or light gray to orange brown, moderately sorted sand with quartz gravels,

silts, and clays.

Lithologic soil logging beneath the Middle River Complex has identified a very heterogeneous

stratigraphy. The underlying soils are composed of silty sands, fine-grained to medium-grained

sands, silty clays, clayey silts, and plastic clay, with the primary lithology being clay to silty clay.

Areas along the waterfronts have been backfilled to their present elevation over past decades. Soils

obtained from fill areas are similar in appearance and composition to soils considered to be native

to the Middle River Complex.

2.1.2.6 Regional Hydrogeology

Sand and gravel zones in the unconsolidated surficial deposits at the Middle River Complex, when

present, may form an unconfined or water table aquifer system (Bennett and Meyer, 1952). The

water table at the Middle River Complex generally conforms to the land surface, with the highest

water levels in interior land areas and the lowest at approximately surface water elevations along


the shoreline. The Patuxent Formation is the most important water-bearing formation in the

Baltimore area. Industrial wells in the southeastern part of the area, specifically Curtis Bay and

Sparrows Point, yield 500–900 gallons per minute (gpm). In these industrialized areas, the

transmissivity and storage coefficient in confined portions of the aquifer average about

50,000 gallons per day per foot (gal/day/foot) and 0.00026, respectively.

The Patapsco Formation is also an important water-bearing formation in industrialized Baltimore,

where it is separated by clay into a lower and an upper aquifer. Industrial wells screened in the

lower aquifer yield as much as 500–750 gpm, with an estimated transmissivity of

25,000 gal/day/foot (Bennett and Meyer, 1952). The upper aquifer yields quantities of water

similar to industrial wells, but likely has a higher overall transmissivity because it is thicker than

the lower aquifer.

2.1.2.7 Middle River Complex Geology

Overall, investigation results indicate complex arrangements of predominantly clay, silty clay, silt,

and clayey silt, with smaller, more permeable zones of silty sand and sand. Thick sequences of

low permeability clay, silty clay, clayey silt, and silt were observed in the northeastern portion of

the site from MRC-MW03 to the central portion of the site between MRC-MW60 and

MRC-MW94D (Figure 3). Lithologic data indicate a thick clay zone up to 50 feet thick underlying

the surficial aquifer. Below this clay zone is a series (up to 105 feet thick) of alternating thick sand

and clay beds. Underlying these alternating beds is another thick clay layer ranging up to 73 feet

thick that is consistent with the expected thickness and placement of the Arundel Formation

(Chapelle and Kean 1985; Vroblesky and Fleck, 1991). Below this lower clay zone are layers of

silty to clayey sand and thick clay, up to 14 and 15 feet thick, respectively.

In the southwestern portion of the Middle River Complex, surficial silty sands and sandy silts are

encountered in the upper several feet of subsurface soil between wells MRC-MW12 to

MRC-MW56 in the northeast. A lower sandy unit 50 feet below mean sea level at MRC-MW14

appears to be contiguous with sand encountered at MRC-MW12 and MRC-MW95D to the

southwest. The upper silty sand unit and the lower sand unit are separated by approximately

30-35 feet of clay and/or silt. These underlying units range up to 80 feet in combined thickness.

Underlying the sand-clay sequence is a thick clay unit ranging up to 76 feet thick that contains


thick sand beds. The persistence of thick clay layers confining the sand units is observed in the

lower portions of all deep wells.

2.1.2.8 Middle River Complex Surficial Aquifer Hydrogeology

Groundwater at the Middle River Complex is encountered at depths ranging from above ground

surface (artesian) to nearly 25 feet below ground surface. Groundwater preferentially flows to the

southeast, south, and southwest, within sandy strata that extend from the central portion of the

Middle River Complex to thicker sandy beds near Dark Head Cove and Cow Pen Creek (Tetra

Tech, Inc., 2014a).

The lower portion of the surficial aquifer in the southeast portion of the Middle River Complex is

divided by silt and silty clay at 20 to 30 feet below mean sea level, with groundwater flow towards

Dark Head Cove. To the southwest, shallow groundwater flows southwest through sandy and silty

material towards Cow Pen Creek. This area has approximately 13 to 18 feet of saturated sandy

material (Tetra Tech, Inc., 2014a).

In 2005, single-well permeability tests (slug tests) were performed to determine the variability of

hydraulic conductivity across the Middle River Complex. Low average hydraulic conductivities

(i.e., soil permeability) were observed within shallow and intermediate wells (arithmetic means of

0.22 and 0.48 feet per day, respectively), with the lowest values in the southern portion of the

Middle River Complex. Permeability values observed in the shallow and intermediate wells are

consistent with lower values published for fine clean sand or sand and silt mixtures. Hydraulic

conductivity values for deep wells range from 0.35 to 9.16 feet per day. The average hydraulic

conductivity of the deeper wells (3.82 feet per day) is approximately 10 times the average

hydraulic conductivity for the shallow and intermediate zones (Tetra Tech, Inc., 2009a).

2.2 GROUNDWATER

Groundwater at Middle River Complex is encountered at depths ranging from ground surface

(artesian) to 26 feet below grade. Shallow groundwater follows site topography and flows radially

from the hydraulically upgradient northern portion of the Middle River Complex at Eastern

Boulevard and immediately south of Buildings A, B, and C to the southeast, south, and southwest

toward Dark Head Cove and Cow Pen Creek.


2.2.1 Groundwater Studies and Remedy

2.2.1.1 Groundwater Background

A risk assessment (Tetra Tech, Inc., 2006) identified trichloroethene, tetrachloroethene, vinyl

chloride, benzene, and certain metals (beryllium, cobalt, nickel, and zinc) as the most significant

contaminants in Middle River Complex groundwater. Recent investigation activities indicate

chlorobenzene compounds (chiefly chlorobenzene and 1,2,4-trichlorobenzene) have also impacted

site groundwater. Chlorinated volatile organic compounds, semi volatile organic compounds, and

petroleum-related hydrocarbons, as well as their degradation products, are the largest groups of

organic chemicals of concern at the Middle River Complex. Chlorinated volatile organic

compounds are in surficial aquifer groundwater in several areas of the facility at concentrations

above the Maryland Department of the Environment groundwater standards.

Petroleum-based fuels, such as gasoline, have numerous chemical constituents. Several volatile

organic compounds associated with fuels are soluble in groundwater and are therefore mobile in

the subsurface. The most commonly detected petroleum-related volatile organic compounds in

surficial aquifer groundwater are benzene, toluene, ethylbenzene, and xylenes, and methyl

tert-butyl ether.

�e contaminant 1,4-dioxane is also a groundwater chemical of concern that has been detected

above its selected screening level and is an emerging contaminant nationwide. �e Maryland

Department of the Environment has not established a groundwater standard for 1,4-dioxane, so for

comparison purposes the Maryland Department of the Environment have suggested using the

United States Environmental Protection Agency Regional Screening Level. Since 1,4-dioxane is

carcinogenic and site groundwater is not used as a drinking resource, a target risk of 10-6 was

applied at the suggestion of the Maryland Department of the Environment. �is results as a

screening level of 0.46 microgram per liter (µg/L) (United States Environmental Protection

Agency, 2018). If groundwater concentrations exceed 0.46 µg/L and surface water concentrations

exceed the risk-based swimming screening level (20 µg/L), a fate and transport assessment of the

plume will be performed. Risk-based site-specific swimming screening levels were developed in

2019 for trichloroethene, cis-1,2-dichloroethene, 1,2,4-trichlorobenzene, polychlorinated biphenyls

and 1,4-dioxane for Dark Head Cove and Cow Pen Creek at the Middle River Complex. �ese risk-


based screening values were approved by the Maryland Department of the Environment in 2019

(Lockheed Martin Corporation, 2019).

Additional details regarding Middle River Complex background and history, including details of

previous environmental investigations and discussions of contaminant source areas, are in the

Middle River Complex Groundwater Remedial Action Plan and the annual groundwater

monitoring reports (Tetra Tech Inc., 2009a–b, 2012a–d, 2013a, 2014a, 2015a, 2016a-b, 2017b; and

AECOM Technical Services, Inc., 2018c). Groundwater monitoring results are currently evaluated

annually, except in groundwater treatment areas, for which results are evaluated more frequently.

2.2.1.2 Off-site and Deep Well Groundwater Monitoring

Off-site groundwater monitoring wells were installed in 2010 along the shorelines of Dark Head

Cove and Cow Pen Creek. �e major volatile organic compounds found in the Middle River

Complex groundwater plumes (trichloroethene, cis-1,2-dichloroethene, vinyl chloride,

chlorobenzene, and benzene) and 1,4-dioxane have not been detected in previous off-site

groundwater sampling events (Tetra Tech, Inc., 2010; 2013a; 2016a). Additionally, four deep wells

were installed off-site beneath the surficial aquifer (but above the Arundel Formation clay) to

assess groundwater quality in the deeper aquifers. Several volatile and semi volatile organic

compounds were detected in these deep wells below Maryland Department of the Environment

groundwater standards during previous off-site and deep well groundwater sampling events (Tetra

Tech, Inc., 2010; 2013a; 2016a). Off-site and deep monitoring wells are sampled every three years

and were sampled as part of this April 2019 groundwater monitoring program, as described in

Section 4.2.4. �e next off-site and deep well sampling event is scheduled for 2022.

2.2.1.3 On-site Groundwater Response Action and Monitoring

�e groundwater response action at the Middle River Complex is implemented in accordance with

an administrative consent order between the Maryland Department of the Environment and

Lockheed Martin Corporation. �e groundwater response action uses enhanced anaerobic in situ

bioremediation to treat three areas exhibiting high groundwater concentrations of trichloroethene

and other chlorinated solvents. �e response action addresses groundwater contamination in the

southeastern trichloroethene area (Block E), the southwestern trichloroethene area (Block G), and

the northern trichloroethene area (Block I) (Tetra Tech, Inc., 2012e). Construction of the

groundwater treatment remedies in Blocks E, G, and I began in early summer 2013.


2.2.1.3.1 Blocks E and F Southeastern Trichloroethene Plume During remedial action activities in Block E, two underground storage tanks were discovered near

the foundation of former Building D. Underground Storage Tank #1 was nearly empty when

discovered, whereas Underground Storage Tank #2 contained high concentrations of

trichloroethene. Both underground storage tanks were removed during installation of the in situ

bioremediation system.

Subsequent investigations indicated that the mass and concentration of trichloroethene near

Underground Storage Tank #2 would not be readily addressed by in situ bioremediation. With

Maryland Department of the Environment approval, Lockheed Martin installed a multi-phase

extraction system in Block E in 2014 that removed most of the mass of trichloroethene that was

present in groundwater near Underground Storage Tank #2. �e multi-phase extraction system

operation was completed in late 2015. After multi-phase extraction system operation, groundwater

samples were collected from approximately 40 Block E monitoring and injection wells in January

and April 2016, to better delineate the trichloroethene plume at locations hydraulically

downgradient (south) of Underground Storage Tank #2.

Sampling results (included in the Block E Tracer Study Report [Tetra Tech Inc., 2016c]) indicated

that the southeastern trichloroethene plume was farther downgradient than previously known and

extended south of MRC-SEMW-6I (located north of Chesapeake Plaza Drive in Block E). A

groundwater investigation between monitoring well MRC-SEMW-6I and Dark Head Cove in

Block F was subsequently conducted to delineate the suspected trichloroethene plume in that area.

Trichloroethene concentrations up to 60,000 µg/L have been detected in groundwater near Dark

Head Cove, and low levels of trichloroethene have been detected in Dark Head Cove surface water

below risk-based swimming screening levels, indicating that contaminated groundwater is

migrating to the cove. Trichloroethene mass discharge rates have been calculated using results

from the groundwater pumping test and hydraulic conductivity estimates and range from 9 to

38 pounds per year, with average and mean rates of approximately 26 and 30 pounds per year,

respectively (Tetra Tech Inc., 2018). Sampling to determine the nature and extent of contamination

was completed and remediation alternatives were defined in Middle River Complex Groundwater

Remedial Action Plan Addendum Number 4 (Tetra Tech, Inc., 2018b). �e remedy for this area of

the site is hydraulic containment and permeable reactive barrier in Block F, existing anaerobic

reductive dechlorination in Block E with monitored natural attenuation and land use controls. The


Groundwater Remedy Blocks E/F 100% Design Basis Report was approved by MDE in June 2019

(Tetra Tech Inc., 2019b).

2.2.1.3.1 Blocks E and F Chlorobenzene Plumes In addition to the presence of trichloroethene, 1,2,4-trichlorobenzene, and related chlorobenzene

compounds are associated with polychlorinated biphenyls for use in former transformers. Elevated

1,2,4-trichlorobenzene concentrations were detected in Block E groundwater and soil during

previous volatile organic compound sampling and are thought to be associated with the release of

polychlorinated biphenyls from former transformers in Block E. The analytical results from the

initial sampling of newly installed monitoring wells in Blocks E and F revealed that chlorobenzene

compounds were present in groundwater in the southeastern and southwestern portions of Blocks

E and F. Specifically, chlorobenzene was detected at MRC-MW126A (located downgradient of

Transformer Room #4) at a concentration of 37 µg/L, while 1,2,4-trichlorobenzene was detected

at MRC-MW130A (south of Transformer Room #3) at a concentration of 150 µg/L. Additional

site investigation has commenced to characterize chlorobenzene contamination and related

detections in southwestern Blocks E and F.

2.2.1.3.2 Block G Plume Semi-permanent injection wells were installed to inject biological amendments into the subsurface.

A tracer study was performed in Blocks G and I (May–July 2014) before the full-scale injection to

determine the main injection parameters.

Two injection rounds were completed at Block G in June 2015 and February 2016. �e second

round included bioaugmentation with Dehalococcoides bacterial culture. Remedial action

objectives determined for these actions have been met, and two years of post-injection monitoring

have been completed. �e Block G Remedial Action Completion Report For Groundwater At Block

G was submitted to the Maryland Department of the Environment in October 2018 (Tetra Tech

Inc., 2018c). �e Maryland Department of the Environment approved No Further Action in April

2019.

2.2.1.3.3 Block I West of Building A Plume Horizontal delineation of the groundwater plume west of Building A was completed in 2018. �e

findings of the investigation determined the plume has not migrated to or beneath Cow Pen Creek.

�e vertical extent of contamination present in a high permeability sand layer beneath the low


permeability clay at MRC-MW119B (trichloroethene at 190 µg/L) and MRC-MW120B

(trichloroethene at 1,460 µg/L) has not been delineated. However, sonic borings installed

downgradient identified low permeability clay at depth likely confining the contamination within

the sand strata (Tetra Tech Inc., 2019). �is area of the site is currently designated for groundwater

monitoring to evaluate plume stability.

2.2.1.3.4 Block I South of Building C Plume Semi-permanent injection wells were installed to inject biological amendments into the subsurface.

A tracer study was performed in Block I (May–July 2014) before the full-scale injection to

determine the main injection parameters.

�ree injection rounds were completed in Block I, with the latest completed in September 2017.

Injections in September 2017 incorporated pumping to lower the groundwater table in the injection

area to control groundwater mounding and mitigate the potential for substrate escaping through

storm drains to Dark Head Cove. �is change was documented in the Maryland Department of the

Environment-approved Groundwater Remedial Action Plan Addendum 4 (Tetra Tech Inc, 2018).

Remedial action objectives determined for these actions have been met, and two years of post-

injection monitoring have been completed. �e Draft Response Action Completion Report for

Groundwater at Block I was submitted to the Maryland Department of the Environment in October

2019 (Tetra Tech Inc., 2019c).

2.2.2 Groundwater Monitoring Optimization Program

A study was conducted to optimize groundwater monitoring at the Middle River Complex (Tetra

Tech, Inc., 2015b). �is study provided the rationale to begin a long-term groundwater monitoring

program at the Middle River Complex to assess the effectiveness of the groundwater remedy, to

determine if continuing or new releases to groundwater are occurring, and to monitor conditions

in areas where elevated concentrations of other constituents will be reduced through monitored

natural attenuation.

�e existing Middle River Complex groundwater monitoring network was evaluated in 2015 to

optimize the number of wells sampled, the chemical analyses performed, and monitoring

frequency. �e optimization study recommended other cost reduction measures to achieve long-

term-monitoring data-quality objectives, reduce sampling costs, and minimize the production and


disposal of investigation derived waste. Future evaluation methods were also developed to

determine if a well has statistically attained the standards governing chemicals in groundwater,

and if a well can be permanently removed from the long-term monitoring program. Since 2015,

several volatile organic compounds concentrations and time-based trends have been evaluated

annually as part of the groundwater monitoring optimization program.

�e site’s monitoring program, new well-installation locations, chemical data needs, sampling

frequency, sampling methods, and analysis methods will all be optimized using site-specific

decision-flow logic diagrams, years of site groundwater chemical data from multiple programs,

and the results of the plume-stability analysis. Chemical groups evaluated for the study will include

volatile organic compounds, semi volatile organic compounds, 1,4-dioxane, perchlorate, metals,

and polychlorinated biphenyls. Data needs will be assessed for the following as part of the 2020

work plan addendum:

• wells that require additional sampling to meet the minimum data criterion for long-term monitoring program evaluation (four rounds of data for volatile organic compounds and two rounds of data for other analyses)

• well data needed to assess the effectiveness of the groundwater remedies

• well data needed to evaluate the monitored natural-attenuation of untreated areas (i.e., areas not part of the groundwater remedy that have constituent concentrations above groundwater standards)

• wells to monitor for potentially unrecognized chemical releases from legacy facility operations

• reactivated or extended sampling in areas where new regulatory thresholds have been established


SECTION 3 INVESTIGATION APPROACH AND METHODOLOGY

The objectives of annual groundwater monitoring at the site are to provide a current round of

synoptic groundwater level measurements and groundwater analytical data for selected monitoring

wells to better understand the nature and extent of contamination. Data are used to evaluate time

series trends for on-site groundwater plumes to assess continuing or new constituent releases to

the aquifer, potential groundwater plumes discharging to surface water bodies, and natural

attenuation of chemicals of concern in groundwater at the Middle River Complex (MRC). The

results of the April 2019 groundwater monitoring are discussed in Section 4.

3.1 SYNOPTIC GROUNDWATER LEVEL MEASUREMENTS

AECOM Technical Services, Inc., (AECOM) personnel completed a synoptic round of

groundwater level measurements on March 25 to 28, 2019. �e air- and water-tight compression

caps on well casings were opened to allow air pressure and groundwater in the casings to reach

equilibrium before a depth-to-water measurement was taken. Upon immediately opening the cap,

a photoionization detector (PID) was used to measure headspace vapor in the well casing, for both

health and safety reasons and to document vapor concentrations within the well casing.

Static water levels were measured using a graduated, electronic, sounding water level meter.

Artesian monitoring wells were gauged by securing a Fernco coupling fitted to a polyvinyl chloride

(PVC) standpipe to the inner PVC casing of the monitoring well. �e water level equilibrated in

the standpipe for a period of at least 15 minutes before obtaining groundwater level measurements.

Total well depth was also measured as part of the synoptic groundwater level measurements.

Site personnel performed reconnaissance to identify wells that were inaccessible due to equipment

storage or material obstruction, and resolved such problems using a hand-held Schonstedt metal

detector and coordinating with MRC personnel. MRC-MW95D and MRC-MW96D were not

gauged or sampled due to the wells being damaged and destroyed, respectively. AECOM personnel

also inspected and documented the condition of monitoring wells, including the condition of the


well casing, the well pad, manway, well gasket, and the need for additional parts, such as

compression caps, bolts, washers, and well locks. Missing parts were addressed during the July

and August 2019 well repairs. Results of the monitoring well repairs performed in 2019 are

presented in Appendix A.

�e static water level was determined by lowering the meter’s probe into the well until the liquid

level indicator emitted an audible tone, indicating the air/water interface. �e water level was read

from the probe cable at the reference mark on the top of the well casing and recorded to the nearest

0.01 foot. If no reference mark was found, AECOM personnel used indelible ink and marked a line

on the north side of the well casing. Water levels and the time of measurement were recorded on

field forms via mobile data apps and compiled in daily field reports (DFRs). Copies of the DFRs

for the event are in Appendix B.

3.2 GROUNDWATER SAMPLING AND CHEMICAL ANALYSIS

AECOM personnel sampled 171 on-site and off-site monitoring wells from April 1 to 23, 2019.

Figure 3 presents the locations of all monitoring wells with the sampled monitoring wells

highlighted. Table 1 presents a complete listing of the 2019 monitoring well network, including

those that could not be sampled due to inaccessibility or damage. �e Table 1 well list is based on

Table 1 of the 2018-2020 Groundwater and Surface Water Monitoring Work Plan Addendum #4

(AECOM, 2019).

3.2.1 Well Purging

Monitoring wells were purged using low-flow sampling procedures (LFSP) before samples were

collected. Purging was completed using peristaltic pumps fitted with dedicated, disposable

Teflon®-lined tubing or submersible bladder pumps positioned in the center of each well’s

saturated screened interval, pumping at a flow rate of between 100 and 500 milliliters per minute

(mL/min). Flow rates were monitored using a graduated cylinder and stopwatch.

�e purpose of using LFSP is to collect groundwater samples from monitoring wells that represent

ambient groundwater conditions in the aquifer. �is is accomplished by setting the intake velocity

of the sampling pump to a flow rate that limits drawdown inside the well. Purging is considered

complete when the groundwater-purge parameters have stabilized, when three saturated well-

casing volumes have been removed, when the well has been purged dry, or after a 90-minute


period, whichever occurs first. During purging, water level drawdown measurements and

groundwater parameters (including pH, temperature, specific conductivity, dissolved oxygen

[DO], oxidation-reduction potential [ORP], and turbidity) were collected every five minutes until

one of the above criteria had been met. Purge completion parameters are defined in Table 2. �ese

data were recorded on low-flow-purge data sheets via mobile data apps; data sheets and completed

DFRs are in Appendix B.

Water quality parameters were measured using a Horiba U-52 water quality meter with flow cell.

Upon arrival at each sampling location, and immediately after the well was opened, the headspace

in monitoring wells was screened with a 3000 MiniRAE PID. Air and water-quality monitoring

equipment was calibrated and inspected daily to ensure precise and accurate measurements. Purged

water was collected in United States Department of Transportation (USDOT)-approved 55-gallon

steel drums. Purge water collected downgradient of Underground Storage Tank (UST) #2 was

separately drummed and managed as F001-listed hazardous waste.

3.2.2 Sample Collection and Preservation

Collected groundwater samples were immediately stored on ice in laboratory-supplied sample

containers until they were picked up by the laboratory courier. Table 3 describes quality

assurance/quality control sampling requirements. Each sample container was sealed and submitted

to the laboratory for analysis with a laboratory-provided chain of custody (COC) form.

3.3 LABORATORY ANALYSES

Samples from subject wells were analyzed for the following constituents (Table 1):

• volatile organic compounds (VOCs; SW-846 Method 8260C)

• 1,4-Dioxane (SW-846 Method 8270D SIM)

• polychlorinated biphenyls (PCBs; USEPA Method 680)

• total metals (SW-846 Method 6020A/7470A)

• hexavalent chromium (USEPA Method 218.6)

• methane, ethane, and ethene (MEE; USEPA Method RSK-175)


• monitored natural attenuation parameters (USEPA Method 300.0, ASTM D6919-09, and Standard Methods 2320, 2540, 4500, and 5310)

ALS Environmental of Middletown, Pennsylvania, performed all laboratory analyses except for

PCBs. PCB samples were analyzed by ALS Environmental in Rochester, New York. Ferrous iron

was analyzed in the field using Hach® test kits.

3.4 DOCUMENTATION

Site activities and observations, including groundwater level measurements, well purge

information, groundwater parameters, time of purging and sampling, and field observations were

recorded on two of Esri’s mobile applications, Survey123 and Collector for ArcGIS. Completed

COC forms and matrix-specific sampling log sheets were also maintained.

3.5 EQUIPMENT DECONTAMINATION

Reusable equipment (e.g., water level meter, submersible bladder pump, water quality meter) was

decontaminated before and after each use. Between each sampling location, decontamination of

reusable equipment involved the following:

• Liquinox® and potable-water wash with distilled water

• distilled water rinse

• air drying

Decontamination fluids were collected for disposal in USDOT approved 55-gallon drums. Rinsate

water from sampling downgradient of UST #2 in the hazardous trichloroethene (TCE) plume area

was segregated from other decontamination fluids and disposed of as F001-listed hazardous waste.

Disposable equipment used in groundwater sampling that did not require decontamination

(e.g., bonded tubing, silicon tubing, poly sheeting, gloves) was disposed of as general refuse.

3.6 WASTE MANAGEMENT

Investigation derived waste generated by groundwater sampling consisted of purge water, rinse

water, and used personal protective equipment (PPE). PPE, poly tubing, and poly sheeting were

placed in industrial trash bags and disposed of as general refuse. �e purge and rinse water were

containerized in USDOT approved 55-gallon steel drums and temporarily staged on wooden


pallets within a secondarily containerized central staging area established in Block E at the MRC.

�is central staging area was used for chemical/physical characterization and to ensure proper

disposal at the end of sampling. Purged groundwater and rinsate water downgradient from UST #2

within the hazardous TCE plume boundary were separately containerized in USDOT approved

55-gallon steel drums and temporarily staged on-site in Block E, in a separate hazardous waste

area with tertiary containment. �e staging area was secured each day and was posted with

appropriate signage.

Drums were labeled with relevant site information, including beginning accumulation date,

description of contents, origin and generator name, and consultant contact information. �ese

temporarily stored wastes were picked up for proper disposal on June 18, 2019. Waste

characterization sampling and analysis were completed before disposal, as required by the

treatment, storage, and disposal facility, Clean Harbors, Inc., in Baltimore, Maryland. �ese

activities were approved by Lockheed Martin Corporation (Lockheed Martin). Investigative

derived waste documentation is presented in Appendix C.

3.7 DATA MANAGEMENT

Laboratory data handling procedures meet the requirements set forth in the laboratory subcontract.

All analytical and field data are maintained in project files, containing copies of the COC forms,

sampling log forms, sampling location maps, and data quality assurance documentation.

3.7.1 Data Tracking and Control

A cradle-to-grave sample tracking system was used from the beginning to the end of sampling.

�e field operations leader coordinated sample tracking before field mobilization. Sample jar labels

were both handwritten in the field and pre-supplied by the laboratory. Labels were reviewed to

ensure their accuracy and adherence to work plan requirements. �e AECOM laboratory task

manager (LTM) coordinated with the analytical laboratory to ensure that they were aware of the

number and type of samples and analyses to expect.

During field sampling, the field operations leader forwarded the COC forms to the LTM and the

laboratory each day that samples were collected. �e LTM confirmed that the COC forms provided

the information required by the work plan. �is allowed early detection of field errors so that

adjustments could be made while the field team was mobilized. �e laboratory submitted an


electronic deliverable for the sample delivery groups. When all electronic deliverables had been

received from the laboratory, the LTM confirmed that the laboratory had performed all analyses

requested.

3.7.2 Data Export to EESH Geographic Information System

AECOM coordinated with Lockheed Martin to load analytical data from this round into Lockheed

Martin’s EESH Geographic Information System enterprise database.

3.7.3 Mobile Data Collection

AECOM personnel used two of Esri’s mobile applications, Survey123 and Collector for ArcGIS,

to optimize field personnel’s ability to locate and record accurate and timely data. �e applications

were used to record depth to groundwater, groundwater quality, and groundwater stabilization

during sampling. Collector also aided personnel with location services, base-map reference, and

the ability to edit well information based on field observations. Survey123 was used to create new

data records, cross reference data tables to access and update well information, and format data

into a database compatible spreadsheet. Upon completion of sampling, the lead field technician

synced with AECOM’s Portal for ArcGIS for data access and processing.

During the April 2019 groundwater sampling event, AECOM’s Portal for ArcGIS experienced a

major crash. �is crash effected data completeness and triggered a corrective action for future

sampling events. Data could not be recovered for six of the wells sampled as part of the 2019

sampling event (MRC-MW27B, MRC-MW94D, MRC-MW101A, MRC-MW101B, MRC-

MW102A, and MRC-MW130A). Analytical data for the above list of wells is present but the wells

are missing geochemical purge completion parameters.

�is publishing error from AECOM’s Portal for ArcGIS was discovered while in the field by

observing that Survey123 was not publishing to Portal (sampling forms were remaining in the

outbox and not listed as sent). �e database manager informed the sampling team that all data

would be captured by manually downloading the data from each of the five field staff’s tablets.

However, the Portal for ArcGIS crash meant that the Portal was unable to handle form updates, so

several versions of the sampling forms were created by the database manager for use and were not

captured post Portal for ArcGIS’s major crash.


Changes to mobile data app collection procedures and corrective actions for future sampling are

as follows:

• Use ArcGIS Online (AGOL) instead of Portal. There have been no stability issues with

AGOL.

• Finalize and test the sampling survey at least one week prior to field mobilization. All field

personnel that will be using Survey123 will submit a test record to ensure that they have

the correct form version and are not having sync issues with their device at least one week

prior to mobilization.

• Include metadata in the sample form that records date and time submitted and a device

identification; this assists in troubleshooting sync issues.

• Never delete project forms or data from field tablets. The Survey123 application will store

all form data on each device after submitting. If an old version of a form is removed from

a device, all data stored on that device associated with that form will also be deleted.

• Daily quality control checks will be conducted by both the database manager in the office

and the field team lead who is tracking which wells have been sampled. In addition, paper

forms will be on hand if there is a malfunction with a tablet or Survey123.

• Screen shots will be taken by the filed staff of parameters that are sampled from each well

and will be saved to the individual tablet in the event of a Survey123 malfunction.

3.8 DATA VALIDATION

Laboratory data were entered into the AECOM sample database and evaluated against cleanup

goals. AECOM performed a manual data review of all samples. Data validation using the EarthSoft

EQuIS™ database’s Automated Validation Assistant tool, which performed a limited data review

(evaluating data completeness, holding times, laboratory and field blank contamination, laboratory

batch quality control, field duplicate precision, and detection limits), was completed concurrent

with the data evaluation. �is review is based on the United States Environmental Protection

Agency (USEPA) National Functional Guidelines for Organic Superfund Methods Data Review

(USEPA, 2017a) National Functional Guidelines for Inorganic Superfund Methods Data Review

(USEPA, 2017b) and the specifics of the analytical method used.


Data validation reports are in Appendix D. Validation of these data concluded that they are

acceptable for their intended uses (i.e., contaminant trending, risk screening and risk assessment).

�e data qualifiers (i.e., flags) applied to the chemical results during data validation are consistent

with the National Functional Guidelines for Organic and Inorganic Superfund Methods Data

Review (USEPA, 2017a; 2017b).

3.9 SUSTAINABILITY APPROACH

AECOM incorporated green and sustainable remediation practices into the MRC groundwater and

surface water monitoring program to advance Lockheed Martin’s Corporate key objectives to

protect, enhance, optimize, and simplify, and highlight the added values that sustainable practices

bring. AECOM implemented sustainable approaches in all aspects of work wherever practical, and

with prior approval from Lockheed Martin and the Remediation Technical Operations contractor.

For the MRC monitoring program, AECOM implemented paper free electronic data collection

across all aspects of the groundwater sampling program. �is data collection approach, as well as

the use of dedicated reusable tubing and rechargeable batteries for field instruments, reduced total

waste and provided resource efficiency. Using local field staff, carpooling, and using locally

sourced materials wherever possible helped reduce overall chemical emissions.


SECTION 4 GROUNDWATER MONITORING RESULTS

Section 4 presents the results and interpretations of the 2019 groundwater sampling. Results of

groundwater level measurements and analytical results are tabulated and presented in this section,

alongside contour maps and maps of the concentrations and distributions of chemicals of concern.

A tabulated summary of all analytical data are presented in Appendix E. �e laboratory analytical

reports with chain of custody (COC) forms are presented in Appendix F. Monitoring well

nomenclature for all wells includes the “MRC-” prefix, so all references to specific wells in

Section 4 will be abbreviated to exclude the prefix (e.g., “MRC-MW102B” to “MW102B” and

“MRC-SEMW-8S” to “SEMW-8S”). Plots of concentration versus time (time-series graphs) for

primary and secondary chemicals of potential concern in select wells are presented in Appendix G.

Note that time series plots were not developed for wells with only one data point.

4.1 GROUNDWATER ELEVATION DATA

Groundwater elevations were gauged in March 2019 and range from above ground surface

(artesian) to 26.04 feet below ground surface (bgs). Groundwater elevations are summarized in

Table 4. �ese data were used to develop groundwater-elevation contour maps of the shallow and

intermediate aquifer systems found at the Middle River Complex (MRC). Contour maps are shown

in Figures 4 and 5, respectively.

Groundwater elevations in the surficial aquifer range from a minimum of -16.12 feet below mean

sea level (msl) at OF08B (off-site near Dark Head Cove) to a maximum of 33.03 feet above msl at

MW57A (in the southern portion of Block I, southeast of Building B). �ese measured

groundwater elevations are consistent with previous observations of a groundwater high in the

center of the site in the southern portion of Block I, with radial flow to the southwest, south, and

southeast toward surface water discharge points at Cow Pen Creek and Dark Head Cove.


4.2 GROUNDWATER ANALYTICAL RESULTS

�e April 2019 groundwater sampling detected results are tabulated in Table 5. All validated

analytical results are summarized in Appendix E. Chemical analytical results were used to generate

plume maps estimating the boundaries of contaminants and their distribution within the plume

footprint (referenced in their respective sections below). Logarithmic contours were used to

account for widely disparate detection values across the MRC.

Analytical results are compared against current Maryland Department of the Environment (MDE)

groundwater standards for volatile organic compounds (VOCs), polychlorinated biphenyls

(PCBs), and metals (MDE, 2018). Exceedances of MDE groundwater standards are highlighted in

yellow on Table 5. MDE has not yet established an advisory level or standard for 1,4-dioxane in

drinking water or groundwater. In lieu of MDE standards, MDE suggested using a screening level

of 0.46 microgram per liter (µg/L), calculated based on a target risk of 10-6 from the United States

Environmental Protection Agency (USEPA) Regional Screening Levels (USEPA, 2018). �is

screening level is adopted as the evaluation criterion within this report. �e 2019 analytical results

are organized below according to shallow, intermediate, and deep aquifers, and offsite results in

Sections 4.2.1, 4.2.2, 4.2.3, and 4.2.4, respectively. Sections 4.2.5 through 4.2.7 present a summary

of monitored natural attenuation parameters, trichloroethene (TCE) plume areas, and VOC trends,

respectively.

4.2.1 Shallow Groundwater Analytical Results

4.2.1.1 Volatile Organic Compounds

VOCs were detected above MDE groundwater standards in 40 of the 74 sampled shallow aquifer

wells. The primary VOCs of concern include tetrachloroethene (PCE), TCE, and their daughter

products.

4.2.1.1.1 Tetrachloroethene PCE was detected in eight monitoring wells and exceeded its MDE groundwater standard

(5.0 µg/L) in three of those wells, with a maximum concentration detected at MW113A

(75.6 µg/L) in the southwestern portion of Block E. Additional exceedances were detected at

MW114A (5.4 µg/L), located side-gradient to the east of MW113A, and MW60A (59.0 µg/L),

which is located in the center of Block I downgradient of Building C.


4.2.1.1.2 Trichloroethene TCE was detected in 46 shallow monitoring wells and exceeded its MDE groundwater standard

(5 µg/L) in 21 of them. Maximum TCE concentrations were detected at SEMW-5S (19,200 µg/L)

in the southeast portion of Block E, and at nearby wells SEMW-8S (14,900 µg/L) and SEMW-9S

(13,000 µg/L) in the southeastern portion of Block F. Additional detections in excess of 1,000 µg/L

were observed in various locations of Block I at MW96A (1,870 µg/L) located to the west of

Building A, MW88A (1,030 µg/L) located to the east of Building C, MW60A which had a historical

high concentration in 2019 of 2,070 µg/L, and MW48A (1,040 µg/L) located to the south of

Building C.

TCE concentrations above the MDE groundwater standard are also detected in shallow aquifer

wells located to the west of the Block I and Block E southeastern TCE plumes. Wells MW25A

(154 µg/L) and MW113A (31.6 µg/L) both exceed the MDE groundwater standard of 5 µg/L.

Additional investigations have commenced in the southwestern portion of Blocks E and Block F

to delineate the nature and extent of contamination in this area.

In 2015 and 2016, the Block G plume received two rounds of remedy injections, including a

bioaugmented injection in the second round, near MW14A, south of the Tilley Chemical Company,

Inc. (Tilley) building. TCE concentrations are less than 19 µg/L in this area.

4.2.1.1.3 cis-1,2-Dichloroethene Forty-seven monitoring wells contained cis-1,2-dichloroethene (cis-1,2-DCE), and six of them

exceeded the MDE groundwater standard (70 µg/L) in the shallow aquifer. �e maximum

cis-1,2-DCE detection was at MW96A (28,600 µg/L) in Block I, west of Building A. Additional

exceedances were observed in Block I south of Building C at MW60A (730 µg/L) and MW48A

(1,780 µg/L), in the southeastern portion of Block F at SEMW-5S (676 µg/L), and in Block F at

SEMW-8S (166 µg/L) and SEMW-9S (103 µg/L). cis-1,2-DCE is a TCE degradation product, not

a source chemical at the MRC.

4.2.1.1.4 Vinyl Chloride Vinyl chloride (VC) was detected in 25 monitoring wells and exceeded its MDE groundwater

standard (2 µg/L) in eight of them. �e maximum VC detection was observed at MW60A

(171 µg/L), which is south of Building C in Block I. VC exceedances were also observed in the

vicinity of MW60A in the southeast portion of Block I, west of Building A, in Block G, and in the


southwestern portion of Block E. VC occurs in close association with elevated TCE concentrations

in Blocks E, G and I.

4.2.1.1.5 Other Volatile Organic Compounds Several additional VOC exceedances in shallow aquifer wells were observed clustered in central

and southern Block E, and in eastern downgradient wells in Block F, and one well in Block I:

• Chlorobenzene—Chlorobenzene was detected in 13 wells and exceeded its MDE groundwater standard (100 µg/L) in two of them, with the maximum concentration detection at MW124A (338 µg/L) in southwestern Block E. �e other exceedance is in MW134A (110 µg/L) in Block F. Additional site investigation has commenced to characterize chlorobenzene contamination and related detections in this area of the MRC.

• 1,2,4-Trichlorobenzene (1,2,4-TCB)—1,2,4-TCB was detected in 12 wells and exceeded its MDE groundwater standard (70 µg/L) in eight of them. �e maximum detection was at MW127A (1,800 µg/L) in southwestern Block E. Other exceedances in southwestern Block E are in the vicinity of MW124A (452 µg/L) and MW43A (695 µg/L), and one exceedance at SEMW-9S (90.7 µg/L) is in southeastern Block F.

• 1,4-Dichlorobenzene (1,4-DCB)—1,4-DCB was detected in 13 wells. It exceeded its MDE groundwater standard (75 µg/L) in three wells in southwestern Block E. �e highest detections were at MW43A and MW124A (125 and 155 µg/L, respectively).

• 1,3-Dichlorobenzene (1,3-DCB)—1,3-DCB was detected in 11 wells. �ere is not a MDE established groundwater standard for 1,3-DCB.

• 1,1-Dichloroethylene (1,1-DCE)—Degradation product 1,1-DCE was detected in 28 sampled wells and exceeded its MDE groundwater standard (7 µg/L) in five of them. �e maximum concentration of 1,1-DCE was observed at MW16A (60.7 µg/L) in Block G. Additional 1,1-DCE exceedances were detected in Blocks I, E, H, and G. All detections are associated with TCE impacted groundwater.

• 1,2-Dichloroethane (1,2-D

2019 GROUNDWATER MONITORING REPORT ......term-monitoring data-quality objectives, reduce sampling...

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