FINAL EXPLANATION OF SIGN IFICANT DIFFERENCES · N:\CLIENT\LAAP\GFPR\Five Year Review\2010...

$: FINAL EXPLANATION OF SIGN IFICANT DIFFERENCES · N:\CLIENT\LAAP\GFPR\Five Year Review\2010 FYR\ESD\LAAP ESD 2011 Final 3-12.docx 3/15/2012 iii LIST OF TABLES Table 2-1 Constituents$
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MMaarrcchh 22001122

Prepared for:

U.S. Army Installation Management Command J&M Business Park 11711 North IH 35, Suite 110 San Antonio, Texas 78233

Prepared by:

4171 Essen Lane Baton Rouge, Louisiana 70809

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002200

Louisiana National Guard Camp Minden Training Site100 Louisiana Blvd. Minden, Louisiana 71055-7908

Camp Minden Training Site

7908

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OOrrddeerr NNuummbbeerr WW991111SS00--0044--FF--00002200

LLAA AAII NNoo.. 88999933

MMaarrcchh 22001122

Prepared for: U.S. Army Installation Management Command J&M Business Park 11711 North IH 35, Suite 110 San Antonio, Texas 78233

Louisiana National Guard Camp Minden Training Site 100 Louisiana Blvd. Minden, Louisiana 71055-7908

Prepared by: Shaw Environmental, Inc. 4171 Essen Lane Baton Rouge, LA 70809

N:\CLIENT\LAAP\GFPR\Five Year Review\2010 FYR\ESD\LAAP ESD 2011 Final 3-12.docx 3/15/2012 i

Table of Contents ___________________________________________

List of Tables ................................................................................................................................................. iii List of Figures ................................................................................................................................................ iii List of Appendices ......................................................................................................................................... iii Acronyms and Abbreviations ......................................................................................................................... iv

1.0 Introduction ..................................................................................................................................... 1-1

2.0 Statement of Purpose ..................................................................................................................... 2-1

3.0 Site History and Contamination ....................................................................................................... 3-1

3.1 History .................................................................................................................................. 3-1

3.1.1 Description and Status of Operable Units ................................................................ 3-1

3.2 Site Contamination – LAAP OU-010 ..................................................................................... 3-5

3.2.1 Area P – Pink Water Lagoons ................................................................................. 3-5

3.2.2 BG-5 – Burning Ground 5 ........................................................................................ 3-6

3.2.3 BG-8 – Burning Ground 8 ........................................................................................ 3-6

3.2.4 Line E – Mine Load Line E ...................................................................................... 3-6

3.2.5 Line F – Mine Load Line F ....................................................................................... 3-6

3.2.6 Line G – Component Assembly Line G ................................................................... 3-6

3.2.7 Line H – Extruder Facility ........................................................................................ 3-7

3.2.8 Y-Line/OWL – Shell Manufacturing Line Y / Oily Waste Landfarm .......................... 3-7

3.2.9 Area B ..................................................................................................................... 3-7

4.0 Selected Remedy ............................................................................................................................ 4-1

4.1 Scope ................................................................................................................................... 4-1

4.2 Performance ......................................................................................................................... 4-1

4.3 Cost ...................................................................................................................................... 4-1

5.0 Basis for the Document ................................................................................................................... 5-1

5.1 Changes to Area B ............................................................................................................... 5-1

5.2 Removal of Dieldrin .............................................................................................................. 5-1

5.2.1 Upper Terrace at Area P ......................................................................................... 5-1

5.2.2 Lower Terrace at Area P ......................................................................................... 5-2

5.2.3 Lower Terrace at BG-5 ............................................................................................ 5-2

5.2.4 Lower Terrace at BG-8 ............................................................................................ 5-2

5.2.5 Upper Terrace at Line G .......................................................................................... 5-3

5.3 Removal of 1,2-Dichloroethane from Line F ......................................................................... 5-3

5.4 FYR Changes to HMX, 2A-DNT, and 4A-DNT ..................................................................... 5-3

6.0 Description of Significant Differences ............................................................................................. 6-1

6.1 Changes to RBRGs .............................................................................................................. 6-1

6.1.1 Scope ...................................................................................................................... 6-1

6.1.2 Performance ............................................................................................................ 6-2

6.1.3 Cost ......................................................................................................................... 6-3

6.2 Changes to Analyte List ........................................................................................................ 6-3

6.2.1 Scope ...................................................................................................................... 6-3

6.2.2 Performance ............................................................................................................ 6-4

6.2.3 Cost ......................................................................................................................... 6-4

N:\CLIENT\LAAP\GFPR\Five Year Review\2010 FYR\ESD\LAAP ESD 2011 Final 3-12.docx 3/15/2012 ii

7.0 Lead and Support Regulatory Agency Comments .......................................................................... 7-1

8.0 Statutory Determinations ................................................................................................................ 8-1

9.0 Public Participation ......................................................................................................................... 9-1

10.0 Authorizing Signature .................................................................................................................... 10-1

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LIST OF TABLES

Table 2-1 Constituents of Concern – Record of Decision for LAAP-010

Groundwater

Table 4-1 2007 ROD Constituent of Concern List By Area

Table 5-1 Contaminant of Concern List Comparison by Area – 2007 ROD to 2011

ESD

Table 5-2 Updated Toxicity Values

Table 5-3 Updated Risk Based Remedial Goals

Table 5-4 Comparison of Risk Assessment Maximum Concentrations to Updated

Risk Based Remedial Goals

Table 6-1 Groundwater Standards and Applicable Areas

LIST OF FIGURES

Figure 1-1 Site Location Map

LIST OF APPENDICES

Appendix A U.S. EPA and LDEQ Concurrence Documentation

Appendix B Newspaper Notice of ESD

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ACRONYMS AND ABBREVIATIONS

1,2-DCA 1,2-Dichloroethane

1,3-DNB 1,3-Dinitrobenzene

2A-DNT 2-Amino-4,6-dinitrotoluene

2,4-DNT 2,4-Dinitrotoluene

2,6-DNT 2,6-Dinitrotoluene

2,4,6-TNT 2,4,6-Trinitrotoluene

4A-DNT 4-Amino-2,6-dinitrotoluene

A-DNTs 2-Amino-4,6-dinitrotoluene and 4-Amino-2,6-dinitrotoluene

BG-5 Burning Ground 5

BG-8 Burning Ground Landfill

BTEX Benzene, Toluene, Ethylbenzene, and Xylenes

CERCLA Comprehensive Environmental Response, Compensation and Liability Act of 1980

COC Constituent of Concern

COPC Constituent of Potential Concern

CPG Central Proving Ground

EPA Environmental Protection Agency

ESD Explanation of Significant Differences

FFA Federal Facilities Agreement

FOSET Finding of Suitability for Early Transfer

FOST Finding of Suitability for Transfer

FRI Follow-on Remedial Investigation

FYR Five Year Review

HMX octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (high melting point explosive)

IC Institutional Control

IRA Interim Remedial Action

IRIS Integrate Risk Information System

kg kilogram

LTM Long Term Monitoring

LUC Land Use Control

MEC Munitions and Explosives of Concern

mg milligram

MNA Monitored Natural Attenuation

MMRP Military Munitions Response Program

MRS Munitions Response Site

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ACRONYMS AND ABBREVIATIONS (CONTINUED)

MTBE Methyl Tertiary Butyl Ether-

NCEA National Center for Environmental Assessment

NCP National Oil and Hazardous Substances Pollution Contingency Plan

OU Operable Unit

OWL Oily Waste Landfarm

PCE Tetrachloroethene

PPRTV Provisional Peer Reviewed Toxicity Values

LAAP Louisiana Army Ammunition Plant

LAP Load, assemble, and pack

LDEQ Louisiana Department of Environmental Quality

RA Remedial Action

RDX Hexahydro-1,3,5-trinitro-1,3,5-triazine or Royal Demolition Explosive

RI Remedial Investigation

RBRG Risk Based Remedial Goals

ROD Record of Decision

SARA Superfund Amendments and Reauthorization Act of 1986

SF Slope Factor

Site Louisiana Army Ammunition Plant Superfund Site

SVOC Semi-Volatile Organic Compound

TCE Trichloroethene

URF Unit Risk Factor

USAEC U.S. Army Environmental Command

VOC Volatile Organic Compound

WOE Weight of Evidence

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1.0 INTRODUCTION

Site Name: Louisiana Army Ammunition Plant, Installation-Wide

Groundwater

Site Location: Doyline, Bossier and Webster Parishes, Louisiana

Lead Agency: U. S. Army

Lead Regulatory Agency: U. S. Environmental Protection Agency, Region 6 (EPA)

Support Regulatory Agency: Louisiana Department of Environmental Quality (LDEQ)

This decision document presents the Explanation of Significant Differences (ESD) for the

Louisiana Army Ammunition Plant (LAAP) Superfund Site (Site), in Doyline, Bossier and

Webster Parishes, Louisiana (Figure 1-1). The ESD is issued in accordance with Section 117(c)

of the Comprehensive Environmental Response, Compensation and Liability Act of 1980

(CERCLA), 42 U.S.C. § 9601 et seq., as amended by the Superfund Amendments and

Reauthorization Act of 1986 (SARA), and the National Oil and Hazardous Substances Pollution

Contingency Plan (NCP), Section 300.435(c)(2)(i). The U.S. Army Environmental Command

(USAEC) is the lead federal agent responsible for the administration of the environmental

restoration at LAAP. The U.S. EPA, Region 6 is the lead regulatory agency and provides

regulatory oversight and approval of proposed actions to be taken at the installation. LDEQ

functions in a support role to the U.S. EPA on Superfund Issues. Coordination of remedial

documents is conducted in accordance with an installation-wide Federal Facilities Agreement

(FFA), which became effective in January 1989. With the concurrence of the U.S. EPA and

LDEQ, the U.S. Army has been delegated the authority to issue this ESD.

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2.0 STATEMENT OF PURPOSE

The U.S. Army is issuing this ESD for the LAAP Installation-Wide Groundwater Operable Unit

(OU) (EPA OU-5/LAAP OU-010) to document changes to the risk based remedial goals

(RBRG) for 2-Amino-4,6-dinitrotoulene (2A-DNT), 4-Amino-2,6-dinitrotoluene (4A-DNT), and

HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine or high melting point explosive). This

ESD is also being issued to document the changes to the list of COCs for several sub-areas. The

list of COCs defined by the Final Record of Decision (ROD) is presented in Table 2-1. The

Final ROD for the Installation-wide Groundwater was signed in August 2007.

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3-1

3.0 SITE HISTORY AND CONTAMINATION

3.1 History

The former Louisiana Army Ammunition Plant was a military installation comprising

approximately 14,949 acres of land near Doyline, Louisiana in Webster and Bossier Parishes. In

1941, the U.S. government acquired ownership of the site. LAAP was subsequently constructed

and used by the U.S. Army to load, assemble, and pack (LAP) munitions and manufacture

ammunition metal parts. In 2005, ownership of LAAP was transferred to the state of Louisiana

and the site renamed Camp Minden. Administrative and residential facilities occupy

approximately 74 acres, 2,970 acres are devoted to production lines and mission support

facilities, and 11,930 acres are woodlands. The layout of the former LAAP facility is shown on

Figure 1-2. The plant is bounded by US Highway 80 to the north, US Highway 164 to the south,

Dorcheat Bayou to the east and by Clarke Bayou to the west. The cities of Shreveport and

Bossier City are located approximately 22 miles west of the installation and the towns of Dixie

Inn and Minden are located just to the northeast. The community of Doyline is located on the

southern boundary and the unincorporated community of Goodwill is located on the northern

boundary.

3.1.1 Description and Status of Operable Units

The contaminated areas/media at LAAP have been separated to facilitate management of the

areas/media. The LAAP OUs are identified as follows:


3-2

LAAP ID

LAAP

OU

EPA

OU LAAP SITE Approved ROD

OU-1 EPA OU-1 refers to an Interim Response

Action implemented at Area P Pink Water

Lagoons (Area P). This area, with other

areas, is later evaluated as a group under

OU-2.

Decision

Memorandum

U.S. Army Corps.

Of Engineers

December 1987

LAAP-001

LAAP-002

LAAP-003

LAAP-004

LAAP-005

LAAP-006

LAAP-007

OU-01

OU-02

OU-03

OU-04

OU-05

OU-06

OU-07

OU-2

OU-2

OU-2

OU-2

OU-2

OU-2

OU-2

Area P Pink Water Lagoons (Area P)

Burning Ground 5 (BG-5)

M-4 Lagoon (M-4)

Burning Ground 8 Landfill (BG-8)

Landfill 3 (LF-3)

Oily Waste Landfarm (OWL)

Burning Ground 8 Pink Water Lagoons

(BG-8)

Soil/Source OU,

September 1996

LAAP-008 OU-08 OU-3 Chromic Acid Etching Facility (Y-Line) Y-Line Facility

Soils, February

2000

LAAP-009 OU-09 OU-4 Nine Load/Assemble/Pack Lines, Three

Test Areas, Area B

LAAP-009 Soil

Sites, July 2006

LAAP-010 OU-10 OU-5 Installation-wide Groundwater LAAP-010

Installation-wide

Groundwater

August 2007

LAAP-011 OU-6 Military Munitions Response Program;

BG-5, Central Proving Grounds (CPG),

Pistol Range. LAAP-011 includes part of

previously operated areas in LAAP-002

and LAAP-009.

LAAP OU-011

MMRP

September 2010

LAAP OU-001 through LAAP OU-007 – Following completion of the Interim Remedial

Action (IRA) at Area P Lagoons, the treated material was returned to the lagoons and capped. A

baseline risk assessment determined that no potential human health or ecological risks are


3-3

associated with the soils and sediments at Area P or the six other OUs (LAAP OU-002 through

007). As established by the statuary declaration of the final ROD (ESE, 1996), NFA is necessary

to ensure protection of human health and the environment, but five-year reviews at Area P are to

be implemented for continued remedial confirmation. The NFA condition is dependent upon the

industrial-use scenario (except M-4 and OWL) as specified in the ROD. The industrial-use

scenario required to ensure protection of human health and the environment was confirmed

during the 2010 FYR.

LAAP OU-008 – As established in the ROD (ETA, 2000), no remedial action is necessary to

ensure protection of human health and the environment at Y-Line soils under an industrial use

scenario. The baseline human health and ecological risk assessments concluded that

unacceptable exposures to hazardous substances will not occur at the Y-Line facility soils in the

industrial use scenario. Because this remedy results in hazardous substances, pollutants, or

contaminants remaining on-site above levels that allow for unlimited use and unrestricted

exposure, a FYR is required to demonstrate that the conditions of the ROD are still being met.

The conditions required by the ROD were confirmed during the 2010 FYR.

LAAP OU-009 – As established in the ROD (Shaw, 2006b), no remedial action is necessary to

ensure protection of human health and the environment for the LAAP OU-009 Soil Sites based

on present and future potential uses. The baseline human health and ecological risk assessments

concluded that unacceptable exposures to hazardous substances will not occur at the LAAP OU-

009 Soil Sites under the present and future potential uses. Because this action results in

hazardous substances, pollutants, or contaminants remaining on-site above levels that allow for

unlimited use and unrestricted exposure, a statutory review will be conducted within five years

after the initiation of the No Action decision to ensure that the No Action alternative is protective

of human health and the environment. The No Action decision is based on the future anticipated

and deed restricted potential uses for commercial/industrial and military purposes. The first FYR

for LAAP OU-009 was conducted in 2010 and determined that the requirements of the No

Action decision were being met.

LAAP OU-010 – As established in the ROD (Shaw, 2007b), a Monitored Natural Attenuation /

Long Term Monitoring and Institutional Controls program for nine remedial action areas within

the LAAP OU-010 Installation-wide Groundwater Operable Unit was selected to aid in

achieving the remedial action objectives and to ensure protection of human health and the

environment based on present and future use scenarios for the shallow groundwater exposure

pathways at the various LAAP OU-010 areas. Specifically, the remedial action objectives

include the restoration of a potential drinking water source to its maximum beneficial use and the

prevention of direct human contact with contaminants of concern by on-site workers until


3-4

RBRGs for drinking water are achieved. As long as land and groundwater use controls remain in

place, the Monitored Natural Attenuation / Long Term Monitoring (MNA/LTM) program will

provide adequate protection for human health and the environment. Groundwater is prohibited

from being used for potable purposes and groundwater modeling indicates that contaminants in

the terrace aquifers are not a risk to the potential receptors. Because this remedy results in

hazardous substances, pollutants, or contaminants remaining on-site above levels that allow for

unlimited use and unrestricted exposure, a statutory review will be conducted within five years

after the initiation of the MNA/LTM remedy to ensure that the remedy is protective of human

health and the environment.

The ROD was finalized in 2007 and the remedial action was implemented in 2008. Two bi-

annual LTM events (2008 and 2010) have been completed and were documented in separate

Remedial Action Monitoring Reports (Shaw, 2008 and 2010). Semi-volatile organic compounds

(SVOCs) (specifically 2,4-Dimethylphenol) and nitroaromatics were inadvertently omitted from

the analyses list for Area B during the 2008 implementation of the MNA/LTM program. Based

on a review of the data for SVOCs and nitroaromatics in Area B, all were detected during one

sampling event within one well and have not been confirmed in re-sampling efforts. Therefore,

the monitoring of SVOCs and nitroaromatics in Area B were deemed unnecessary and these

compounds were not sampled for during the 2010 MNA/LTM sampling event and were removed

from the list of COCs at Area B. If the agencies review this ESD and determine that these

compounds have been rightfully omitted from the MNA/LTM program, these compounds will be

removed from the constituent of concern (COC) list at Area B.

The first five year review (FYR) for LAAP OU-010 was conducted in 2010. It determined that

the selected remedy is protective of human health and the environment. During the 2010 FYR,

the appropriateness of the use of surrogate values for 2A-DNT, 4A-DNT, and HMX was

reviewed. It was determined that the RBRGs calculated during the risk assessment initially

completed in 2000 and finalized in 2005 were overly conservative. This ESD is being submitted

to document the changes to the RBRGs for HMX, 2A-DNT, and 4A-DNT. If the agencies

review this ESD and determine that the new RBRGs are sufficiently protective of human health

and the environment, the new RBRGs will be used to evaluate the sample results from the next

bi-annual LTM event that is scheduled to be completed in 2012.

LAAP OU-011 – The Army performed a Remedial Investigation (RI) for three Military

Munitions Response Program (MMRP) sites (BG-5, CPG, and the Pistol range). As presented in

the final ROD (HDR/e2M, 2010), a Land Use Controls (LUC) (both engineering and

institutional) program for three remedial action areas (BG-5, CPG, and the Pistol Range) within

the LAAP MMRP was selected to achieve the remedial action objectives and to ensure


3-5

protection of human health and the environment based on present and future use scenarios. For

the BG-5 and CPG Munitions Response Site (MRS), the purpose of the selected remedy is the

reduction or elimination of human contact with munitions and explosives of concern (MEC) that

are potentially present below the ground surface or that may be exposed by human activities

(digging). For the Pistol Range MRS, the purpose of the selected remedy is to reduce or

eliminate human contact with the residual lead present in the soil. Because these remedies

results in hazardous substances, pollutants, or contaminants remaining on-site above levels that

allow for unlimited use and unrestricted exposure, a statutory review will be conducted within

five years after the initiation of this remedial action to ensure that the alternatives are protective

of human health and the environment.

As of January 2005, the facility was transferred to the State of Louisiana (now called Camp

Minden) and the use of former LAAP areas remain as military/industrial as specified in the

RODs, and therefore LAAP OU-001, LAAP OU-008, and LAAP OU-009 continue to meet the

NFA land use restrictions. The MNA/LTM and Institutional Control programs also ensure that

LAAP OU-010 is protective of human health and the environment. The LUC program ensures

that LAAP OU-011 is protective of human health and the environment.

3.2 Site Contamination – LAAP OU-010

The nature and extent of groundwater contamination at LAAP was evaluated using groundwater

samples collected from monitoring wells, piezometers, and direct push borings. Selected

monitor wells (42 total wells in both upper and lower terrace aquifers) were chosen for the 2010

bi-annual sampling event as part of the LTM of the Remedial Action (RA) alternative, MNA.

Based on the results of the risk assessment, the analyte list for monitoring was tailored to each

area and was presented in the ROD. This analyte list was revised based on recommendations in

the 2008 Remedial Action Monitoring Report (Shaw, 2009). The analyte list has since been

revised based on recommendations in the 2010 Remedial Action Monitoring Report (Shaw,

2010) and the 2010 – Five Year Review (Shaw, 2011). Brief discussions of the number of wells

sampled during the 2010 LTM sampling event and the analyte list for each area included in

LAA OU-010 are presented below.

3.2.1 Area P – Pink Water Lagoons

There were 15 wells sampled at Area P during the 2010 LTM event. Six of the wells were

located in the Upper Terrace and nine of the wells were located in the Lower Terrace. The

monitored analytes in Area P are:

• Nitroaromatics -

o 1,3-dinitrobeneze (1,3-DNB);


3-6

o 2,4-dinitrotoluene (2,4-DNT);

o 2,6-dinitrotoluene (2,6-DNT);

o 2,4,6-trinitrotoluene (2,4,6-TNT);

o 2A-DNT;

o 4A-DNT;

o HMX; and

o Hexahydro-1,3,5-trinitro-1,3,5-triazine or Royal Demolition Explosive (RDX)

• Volatile organic compounds (VOCs) -

o Tetrachloroethene (PCE); and

o 1,2-Dichloroethane (1,2-DCA).

3.2.2 BG-5 – Burning Ground 5

There were four wells sampled at BG-5 during the 2010 LTM event. All four of the wells are

located in the Lower Terrace. The monitored analytes in BG-5 are nitroaromatics (2,4,6-TNT,

2,4-DNT, 2,6-DNT, 2A-DNT, 4A-DNT, HMX, and RDX).

3.2.3 BG-8 – Burning Ground 8

There were four wells sampled at BG-8 during the 2010 LTM event. All four of the wells are

located in the Lower Terrace. The monitored analytes in BG-8 are nitroaromatics (2,4,6-TNT,

2,6-DNT, 2A-DNT, 4A-DNT, HMX, and RDX).

3.2.4 Line E – Mine Load Line E

Three wells were sampled at Line E during the 2010 LTM event. All three of the wells are

located in the Upper Terrace. The monitored analytes in Line E are nitroaromatics (2,4,6-TNT,

2,4-DNT, 2,6-DNT, 2A-DNT, 4A-DNT, HMX, and RDX).

3.2.5 Line F – Mine Load Line F

There were four wells sampled at Line F during the 2010 LTM event. All four of the wells are

located in the Lower Terrace. The monitored analytes in Line F are nitroaromatics (2,4-DNT,

2,6-DNT, 2A-DNT, 4A-DNT, HMX, and RDX).

3.2.6 Line G – Component Assembly Line G

There were two wells sampled at Line G during the 2010 LTM event. Both of the wells are

located in the Upper Terrace. The monitored analytes in Line G are nitroaromatics (HMX and

RDX).


3-7

3.2.7 Line H – Extruder Facility

There were two wells sampled at Line H during the 2010 LTM event. Both of the wells are

located in the Upper Terrace. The monitored analytes in Line H are nitroaromatics (HMX and

RDX).

3.2.8 Y-Line/OWL – Shell Manufacturing Line Y / Oily Waste Landfarm

There were five wells sampled at Y-Line during the 2010 LTM event. All of the wells are

located in the Lower Terrace. The monitored analytes in Y-Line are VOCs (PCE and

trichloroethene (TCE)).

3.2.9 Area B

There were three wells sampled at Area B during the 2010 LTM event. All of the wells are

located in the Upper Terrace. The analytes monitored for in Area B are benzene, toluene,

ethylbenzene, and xylenes (BTEX) and methyl tertiary butyl ether (MTBE).


4-1

4.0 SELECTED REMEDY

4.1 Scope

The Final ROD for LAAP OU-010 Installation-wide Groundwater was signed on July 24, 2007.

The risk management approach that was selected entails the use of MNA as a passive approach

for achieving the Remedial Objectives for contaminated groundwater at LAAP. Specifically, the

remedial objectives include the restoration of a potential drinking water source to its maximum

beneficial use and the prevention of direct human contact with COCs by on-site workers until

RBRGs for drinking water are achieved.

The primary component of this remedy is the development of a LTM program. The MNA/LTM

program specifies the monitoring wells to be sampled, the monitoring schedule, the analytical

parameters, and the reporting requirements. The MNA/LTM program includes bi-annual (every

two years) sampling events of monitoring wells screening the Upper and Lower Terrace sands

until cleanup goals are achieved. The duration of this MNA/LTM program is anticipated to be

less than 30 years. Groundwater samples are analyzed for nitroaromatic explosives and VOCs,

as necessary at each area. Table 4-1 presents the original analyte list and remedial goals by area

as presented in the 2007 ROD.

Additional components of the remedy include incorporation of existing deed restrictions from the

Finding of Suitability for Transfer (FOST) and Finding of Suitability for Early Transfer

(FOSET) that provide Institutional Controls (ICs) that prohibit the use of the shallow

groundwater for drinking and prevent the installation of wells in the shallow groundwater.

4.2 Performance

The performance of the remedy is evaluated based on the restoration of the groundwater to its

maximum beneficial use and also through protection of human health and the environment. The

performance of the remedy is evaluated through LTM conducted every two years. The

performance is also evaluated by continuously monitoring compliance with the Land Use

Controls / Groundwater Use Controls (LUC/GUC) and annually reviewing and updating as

necessary the Environmental Land Use Restriction Map.

4.3 Cost

When the Final ROD for LAAP OU-010, Installation-wide Groundwater was signed in July

2007, the costs were:

Estimated Capital Cost: $0


4-2

Estimated Present Worth O&M Cost: $250,000 bi-annually

Estimated Total Present Worth Cost: $1,965,000


5-1

5.0 BASIS FOR THE DOCUMENT

The ROD for LAAP OU-010 Installation-wide Groundwater was finalized in 2007 and the

remedial action was implemented in 2008. Two bi-annual LTM events (2008 and 2010) have

been completed and were documented in separate Remedial Action Monitoring Reports (Shaw,

2009 and 2010). Based on the results of the risk assessment, the analyte list for monitoring was

tailored to each area and was presented in the ROD (Shaw, 2007). Recommendations for

revision of the analyte list have been presented in the two Remedial Action Monitoring Reports

(Shaw, 2009 and 2010) and the Five Year Review – 2010 (Shaw, 2011). For comparison

purposes, Table 5-1 presents the original analyte list by area presented in the ROD (Shaw, 2007)

beside the revised analyte list documented by this ESD. The changes to the analyte lists are

indicated by shaded cells.

5.1 Changes to Area B

Based on further review of the data for SVOCs (specifically 2,4-Dimethyphenol) and

nitroaromatics in Area B, these constituents were detected during one sampling event (1998)

within one well (MW2-12) and were not confirmed in re-sampling conducted in 2002.

Therefore, the monitoring of SVOCs and nitroaromatics in Area B are deemed unnecessary and

these COCs are removed from the list of COCs at Area B.

5.2 Removal of Dieldrin

Dieldrin is a constituent on the analyte lists for Area P, BG-5, BG-8, and Line G for the

MNA/LTM program. Dieldrin is a highly stable and persistent pesticide whose use began in the

1950s. In 1974 the U.S. EPA banned Dieldrin for the use in termite control. In 1987 the U.S.

EPA extended that decision by banning all uses of Dieldrin. Dieldrin’s detection at the LAAP

site is the result of former pesticide practices and is not related to former ammunition practices at

the site. With the LUC / GUC in place for shallow groundwater, the ingestion risk values are

within the acceptable risk levels and any remaining risks will not contribute significantly to the

total risk across the medium.

5.2.1 Upper Terrace at Area P

Three sampling events (1981, 1990, and 1998) including Dieldrin monitoring have been

performed in the Upper Terrace at Area P. Over the three sampling events, 25 samples were

collected from 19 wells and Dieldrin was detected only twice. The two detections, both of which

exceeded the regulatory standard, occurred during the 1998 sampling event in wells GO109

(directly associated with Area P) and GO111 (located up gradient of Area P monitoring area).


5-2

Based on the low frequency of detections of Dieldrin in Area P and the locations of the two

detections associated with the Upper Terrace at Area P, it is concluded that monitoring for

Dieldren in the Upper Terrace of Area P is unnecessary. Therefore, Dieldrin is removed from

the list of COCs monitored in the Upper Terrace at Area P.

5.2.2 Lower Terrace at Area P

Two sampling events (1990 and 1998) including Dieldrin have been performed in the Lower

Terrace at Area P. During the two sampling events, 14 samples were collected from 14 wells

and Dieldrin was detected only once. The single detection, which exceeded the regulatory

standard, occurred during the 1998 sampling event in well GO145 (located over 3,000 feet to the

southwest, outside LAAP facility boundary and down gradient of Area P monitoring area).

Based on the low frequency of detection and the location of the single detection, it is concluded

that monitoring for Dieldrin in the Lower Terrace of Area P is unnecessary. Therefore, Dieldrin

is removed from the list of COCs monitored in the Lower Terrace at Area P.

5.2.3 Lower Terrace at BG-5

Four sampling events (1990, 1998, 2001, and 2002) including Dieldrin have been performed in

the Lower Terrace at BG-5. Over the four sampling events, 34 samples were collected from 18

wells and Dieldrin was detected only twice. The two detections, both of which exceeded the

regulatory standard, occurred during the 1998 sampling event in wells OW7 (northern section of

BG-5) and GO118 (southern section of BG-5). The locations of the wells indicate that the

detections are either isolated local sources or aberrations and not part of a larger plume. Based

on the low frequency of detection and the locations of the two detections, it is concluded that

monitoring for Dieldrin in BG-5 is unnecessary. Therefore, Dieldrin is removed from the list of

COCs monitored in the Lower Terrace at BG-5.

5.2.4 Lower Terrace at BG-8

Five sampling events (1989, 1990, 1998, 2001, and 2002) including Dieldrin have been

performed in the Lower Terrace at BG-8. Over the five sampling events, 64 samples were

collected from 30 wells and Dieldrin was detected only five times. The five detections, all of

which exceeded the regulatory standard, occurred during the 1998 sampling event in wells

GO029, GO039, GO073, GO150 and GO151. However, only one of these wells (GO029) is

directly associated with BG-8. The other four wells are all located outside the boundary of the

LAAP facility and either up gradient or cross gradient from BG-8. Based on the low frequency

of detection and the localized nature of Dieldrin in BG-8, it is concluded that monitoring for

Dieldrin in BG-8 is unnecessary. Therefore, Dieldrin is removed from the list of COCs

monitored in BG-8.


5-3

5.2.5 Upper Terrace at Line G

One sampling event in 1998 including Dieldrin was performed in Line G. Five samples were

collected from three wells and two direct push samples. Dieldrin was detected only once

(GO223) and exceeded the regulatory standard. However, the reported concentration was

qualified as an estimated value below the detection limit. Additionally, the reported

concentration was only marginally above the RBRG. Based on the circumstances of the single

detection in Line G (estimated concentration only marginally above the RBRG), it is concluded

that monitoring for Dieldrin in Line G is unnecessary. Therefore, Dieldrin is removed from the

list of COCs monitored in Line G.

5.3 Removal of 1,2-Dichloroethane from Line F

1,2-DCA is a constituent on the analyte list for Line F. Based on a review of the data for 1,2-

Dichloroethane at Line F, there were two detections during one sampling event (1996). The first

detection occurred at well GO245 and was not confirmed during re-sampling in 1998. The

second detection was from a sample that appears to have been taken from a temporary

monitoring well (BH0133LF29) in 1996. With the low frequency of detection and the locations

of the detections, it is concluded that monitoring for 1,2-DCA at Line F is unnecessary.

Therefore, 1,2-DCA is removed from the list of COCs at Line F.

5.4 FYR Changes to HMX, 2A-DNT, and 4A-DNT

The first FYR for LAAP OU-010 Installation-wide Groundwater was conducted in 2010. It

determined that the selected remedy is still protective of human health and the environment.

During the course of the FYR, the toxicity data used to complete the risk assessment was

reviewed and some changes were noted. During the risk assessment, conservative carcinogenic

surrogate values were used to calculate RBRGs for 2A-DNT, 4A-DNT, and HMX. To-date,

EPA has not determined that these constituents are carcinogenic. Therefore, the appropriateness

of the surrogate values for these constituents as used and presented in the FYR is reviewed

below.

The LAAP Follow-on Remedial Investigation for Soils and the Site-Wide Groundwater Operable

Unit (FRI) (Shaw, 2005) completed a risk assessment (initially begun by PMC Environmental in

2000) in which certain constituents of potential concern (COPCs) were assessed as potential

carcinogens, including the development of EPA (1986) cancer weight-of-evidence (WOE)

designations, oral/dermal slope factors (SF) and inhalation unit risk factors (URF). A review of

Section 6.4 of the FRI Toxicity Assessment and accompanying Tables 6.4-1 Cancer Toxicity

Data – Oral/Dermal and 6.4-2 Cancer Toxicity Data – Inhalation of the FRI revealed several


5-4

COPCs incorrectly evaluated as potential carcinogens. Those relevant for this discussion are

limited to 2A-DNT, 4A-DNT and HMX.

The oral/dermal cancer data compiled in Table 6.4-1 for these chemicals, all of which was

attributed to the EPA Integrated Risk Information System (IRIS) accessed in November 2002, is

summarized below:

Chemical Weight-of-Evidence Oral SF

(mg/kg-day)-1

Inhalation SFa

(mg/kg-day)-1

2A-DNT B2 6.8E-1 6.8E-1

4A-DNT B2 6.8E-1 6.8E-1

HMX C 1.1E-1 1.1E-1

Weight-of-evidence designations: B2 – probable human carcinogen; C – possible human

carcinogen.

a The oral slope factor was adopted for inhalation exposure without regard for exposure route-

specific differences in toxicokinetics or mechanism of toxicity.

The IRIS database (EPA, 2010) is an ‘evergreen’ system in which the toxicity evaluations for

individual chemicals are revised when new data become available. A review of IRIS conducted

on October 24, 2010 revealed that 2A- and 4A-DNT (A-DNTs) have never been included in the

IRIS database. The attribution of their cancer assessments to IRIS, therefore, is incorrect. The

WOE and oral SF values presented in the risk assessment for the A-DNTs are those available on

IRIS for a 2,4-DNT/2,6-DNT mixture. The DNTs are structurally similar to the A-DNTs. It

appears that the carcinogenicity assessment of the DNT mixture was adopted for the A-DNTs

based on molecular structural similarity because chemical-specific data are not sufficient with

which to evaluate the potential carcinogenicity of the A-DNTs.

The origin of the carcinogenicity assessment of HMX in Table 6.4-1 of the FRI is less clear.

IRIS has consistently presented a WOE for HMX of D (not classifiable as to carcinogenicity to

humans) since 1993 when the chemical first appeared on IRIS. The oral SF presented for HMX

is the value on IRIS for RDX. RDX is another cyclical nitrated explosive compound; however,

its molecular morphology is quite dissimilar to that of HMX, and it is unclear whether it was

selected as a surrogate for HMX.


5-5

The EPA (1986) Guidelines for Carcinogen Risk Assessment states that cancer potency factors

are developed only for chemicals in WOE Group A (known human carcinogen), Group B

(probable human carcinogen) and Group C (possible human carcinogen), and only if the

available toxicological data are sufficient. Given that the data were not sufficient for WOE

determination of the A-DNTs, and the WOE determination of HMX was Group D, it is

inappropriate to develop cancer potency factors for these compounds.

EPA (2003) released a revised three-tiered hierarchy by which toxicity assessments should be

selected, as follows:

• Tier 1: Verified assessments available on IRIS.

• Tier 2: Provisional Peer Reviewed Toxicity Values (PPRTV) developed by the U.S.

EPA’s National Center for Environmental Assessment (NCEA), but which have not yet

undergone the rigorous review required for inclusion on IRIS.

• Tier 3: Values developed by other federal agencies and some state agencies.

Transparency in the derivation, methodology similar to and compatible with the NCEA

methodology, and peer review are important considerations when choosing among

multiple Tier 3 options.

Above all is the EPA (2003) admonishment to use the best science. The purpose of the EPA

(2003) hierarchy is to ensure that only toxicity values of sufficient quality are used for risk

characterization or to develop cleanup levels for performing site management. Toxicity values

that are not of sufficient quality may be useful for certain screening purposes, but are not to be

used to guide site management. Accordingly, many IRIS evaluations note that the data are

inadequate and toxicity values are not developed. Also, many of the PPRTV manuscripts

conclude, “It should also be noted that some PPRTV manuscripts conclude that a PPRTV cannot

be derived based on inadequate data.” According to the EPA (2003) hierarchy, it is

inappropriate to choose a toxicity value from a Tier 3 source when IRIS or PPRTV evaluation of

the same data base for a given chemical concludes that the data are inadequate.

Such is the case with the carcinogenicity assessment of the A-DNTs. EPA (2005) reviewed the

available cancer data and determined that the data “are inadequate for an assessment of human

carcinogenic potential,” and that the “Lack of oral carcinogenic data and

pharmacokinetic/pharmacodynamic information precludes derivation of an oral slope factor…”

In summary, adherence to the EPA (2003) hierarchy precludes developing cancer potency factors

for the A-DNTs from chemical-specific data or by analogy until adequate data becomes

available, because NCEA has determined that the currently available data are inadequate.


5-6

Similarly, adherence to the EPA (2003) hierarchy precludes developing cancer potency factors

for HMX from chemical-specific data or by analogy until adequate data becomes available,

because IRIS has determined that the available data are inadequate.

Based on the above, oral and dermal reference doses were identified for these three compounds

during the FYR and a RBRG was re-calculated using a hazard index equal to 1.0. These new

reference doses and new RBRGs are presented in Table 5-2. A comparison of the old and new

RBRG’s for these three compounds are found in Table 5-3.

A review of the data collected as part of the baseline human health and ecological risk

assessment was conducted. The maximum concentrations for 2A-DNT, 4A-DNT, and HMX for

12 areas were compared to the new RBRGs (Table 5-4). The maximum values of HMX used to

conduct the risk assessment in the 12 areas listed in Table 5-4 were below the new RBRG for

HMX. Therefore, HMX should never have been listed as a COC in the ROD (Shaw, 2007). The

maximum value for 2A-DNT used to conduct the risk assessment in Line F is below the new

RBRG. 2A-DNT should never have been listed as a COC for Line F. The maximum risk

assessment value of 4A-DNT in Line F and the values of 2A-DNT and 4A-DNT in BG-8 exceed

the new RBRG and are properly included as COCs.

The 2010 data for these three compounds was re-screened using the new RBRG based on the

hazard index of 1.0. The newly screened data is presented in Table 8-5 of the Five Year Review

– 2010 (Shaw, 2011). After a review of the data, it is determined that all 2010 sample results for

HMX (within the eight areas that list this compound as a COC) remain below the new RBRG.

Also, 2010 sample results for 2A-DNT and 4A-DNT are now below the new RBRGs in BG-8

and Line F.

Based on the updated toxicity values and determination that the new RBRGs are sufficiently

protective of human health and the environment, this ESD approves the new RBRGs. Therefore,

HMX is removed from the list of COCs for the eight areas that list it as a COC.


6-1

6.0 DESCRIPTION OF SIGNIFICANT DIFFERENCES

This ESD documents the U.S. Army’s decision to update the RBRGs for HMX, 2A-DNT, and

4A-DNT and to eliminate certain analytes from various sub-areas of LAAP OU-010. The

differences include:

• Updated RBRGs for three separate compounds; and

• Revised analyte list by eliminating certain analytes for eight of the nine separate areas.

This section highlights changes in scope, performance, and cost between the remedy as presented

in the ROD and the action now proposed. Cost estimates are expected to provide an accuracy of

plus 50 percent to minus 30 percents.

6.1 Changes to RBRGs

This proposed change significantly changes the ROD by changing the RBRGs of three analytes.

The 2007 ROD for LAAP OU-010 listed the RBRGs for 2A-DNT, 4A-DNT, and HMX as 1.2E-

04 mg/L, 1.2E-04 mg/L, and 7.7E-04 mg/L, respectively. During the First FYR conducted for

LAAP OU-010, the toxicity values used in the calculations of the RBRGs were reviewed. As

discussed in detail in Section 5.0 of this report, the RBRGs for 2A-DNT, 4A-DNT, and HMX

were updated based on more appropriate toxicity values. The updated RBRGs for 2A-DNT, 4A-

DNT, and HMX are 1.8E-02 mg/L, 1.8E-02 mg/L, and 1.8 mg/L, respectively. Table 5-3

summarizes the initial and final RBRGs for the three compounds.

6.1.1 Scope

The scope of the ROD has been significantly changed by the events documented in this ESD.

The ROD selected the remedy of MNA and LUC with LTM to evaluate remedy performance.

From this respect, the ESD does not change the remedy. However, the cumulative efforts of the

proposed changes significantly change components of the LTM program. The RBRGs for three

compounds (2A-DNT, 4A-DNT, and HMX) were updated with more appropriate toxicological

data. The ESD eliminates the monitoring and reporting of constituents with overly conservative

RBRGs. There is no change in the protection of human health and the environment.

The updated RBRG for HMX resulted in the removal of HMX monitoring in Area P, BG-5, BG-

8, Area B, Line E, Line F, Line G, and Line H. Concentrations of HMX in these areas do not

exceed the new RBRG and can be considered to have achieved compliance. Except for Area B,

the wells in these areas will continue to be sampled for other explosive compounds. Explosives

monitoring in Area B was determined to be unnecessary and is discussed as part of the second

significant difference.


6-2

The updated RBRG for 2A-DNT resulted in the removal of 2A-DNT monitoring at Line F.

Concentrations of 2A-DNT at Line F do not exceed the new RBRG. However, wells in Line F

will continue to be sampled and monitored for other explosive compounds.

The updated RBRG for 4A-DNT does not eliminate monitoring for 4A-DNT at any sub-areas on

LAAP OU-010. The concentrations of 4A-DNT in Area P, BG-5, BG-8, Line E, and Line F

exceed the new RBRG and cannot be considered to have achieved compliance. Explosives

monitoring (including 4A-DNT) in Area B was determined to be unnecessary and is discussed as

part of the second significant difference.

6.1.2 Performance

The performance of the MNA remedy will continue to be monitored by bi-annual LTM. The

performance of the remedy is evaluated based on the restoration of the groundwater to its


performance monitoring is changed by eliminating monitoring for constituents with overly

conservative RBRGs.

The new RBRGs for the three compounds are:

• 2A-DNT – 1.8E-02 mg/L;

• 4A-DNT – 1.8E-02 mg/L; and

• HMX – 1.8 mg/L.

Monitoring of 2A-DNT at Line F and HMX at Area P, BG-5, BG-8, Line E, Line F, Line G, and

Line H will be discontinued. The new RBRGs for these two compounds lead to achievement of

compliance more quickly in the areas listed above. The concentrations of 4A-DNT are still

above the new RBRG and will continue to be monitored. The changes documented in this ESD

will result in some of the constituents achieving compliance more quickly at certain areas.

However, these updated RBRGs will not change the overall time to compliance or the

boundaries of the explosives groundwater plume. The updated RBRGs would be used, along

with the standards for the other constituents, to evaluate the performance of the MNA/LTM

remedy. The overall remedy performance would not be changed by the significant differences

outlined in this ESD.

This significant difference does not change the evaluation of performance by monitoring

compliance with the Land Use Controls / Groundwater Use Controls (LUC/GUC) and reviewing

and updating as necessary the Environmental Land Use Restriction Map.


6-3

6.1.3 Cost

The ROD estimated a present worth for bi-annual sampling and reporting of $250,000 bi-

annually. The changes documented in this ESD will affect the cost of reporting and the

analytical costs. The anticipated reduction in cost is $15,000 bi-annually. Therefore, the

Estimated Present Worth for O&M is reduced to $235,000. Over 30 years, that would result in a

reduced Total Present Work Cost of $1,964,550.

6.2 Changes to Analyte List

This proposed change significantly changes the ROD by changing the analyte list by eliminating

certain analytes from eight of the nine sub-areas. The 2007 ROD for LAAP OU-010 specified

the analytes to be evaluated at each sub-area of LAAP OU-010, which are presented in Table 4-1

of this ESD. Table 5-1 provides a side by side comparison of the analyte list for the 2007 ROD

and the updated analyte list based on the information presented in this ESD document. Table 6-1

summarizes the groundwater standards and the final analyte list (including updates documented

in this ESD) for sub-areas in LAAP OU-010.

6.2.1 Scope

The scope of the ROD has been significantly changed by the events documented in this ESD.

The analyte lists for eight areas (Area P, BG-5, BG-8, Area B, Line E, Line F, Line G, and Line

H) were updated based on the elimination of monitoring for unnecessary compounds. All eight

areas will continue to be monitored for COCs.

As discussed in detail in Section 5.0 of this ESD, the changes in the analyte list include:

• Removal of monitoring for SVOC and nitroaromatic compounds for Area B – A review

of data for SVOCs (2,4-dimethylphenol) and nitroaromatics (2,6-DNT, 4A-DNT, HMX,

and RDX) at Area B indicate constituents were detected in one well during one sampling

event. The detections were not confirmed in re-sampling efforts;

• Removal of monitoring for Dieldrin for Area P, BG-5, BG-8, and Line G – Dieldrin

detections at LAAP are the result of pesticide practices not related to ammunition

practices at the site. Risk levels remain acceptable when LUC/GUC are in place for

shallow groundwater;

• Removal of monitoring for 1,2-DCA at Line F – A review of data for 1,2-DCA at Line F

indicated 1,2-DCA was detected twice in 1996. One detection (well GO245) was not

confirmed during re-sampling in 1998 and the second detection was taken from a

temporary monitor well;


6-4

• Updated RBRG for HMX results in the removal of HMX monitoring for Area P, BG-5,

BG-8, Area B, Line E, Line F, Line G, and Line H. Concentrations of HMX in these

areas do not exceed the new RBRG and can be considered to have achieved compliance;

• Updated RBRG for 2A-DNT results in the removal of 2A-DNTmonitoring for Line F.

Concentrations of 2A-DNT at Line F do not exceed the new RBRG;

6.2.2 Performance

The performance of the MNA remedy will continue to be monitored by bi-annual LTM. The

performance of the remedy is evaluated based on the restoration of the groundwater to its


performance is changed and made more efficient by eliminating monitoring and reporting for

unnecessary constituents.

This significant difference does not change the evaluation of performance by monitoring

compliance with the Land Use Controls / Groundwater Use Controls (LUC/GUC) and reviewing

and updating as necessary the Environmental Land Use Restriction Map.

6.2.3 Cost

The ROD estimated a present worth for bi-annual sampling and reporting of $250,000 bi-

annually. The changes documented in this ESD will affect the cost of reporting and the

analytical costs. The anticipated reduction in cost is $15,000 bi-annually. Therefore, the

Estimated Present Worth for O&M is reduced to $235,000. Over 30 years, that would result in a

reduced Total Present Work Cost of $1,964,550.


7-1

7.0 LEAD AND SUPPORT REGULATORY AGENCY COMMENTS

The U.S. EPA is the lead regulatory agency for LAAP OU-010. The U.S. EPA has been

consulted and provided the opportunity to comment on this ESD in accordance with the NCP §§

300.435 (c)(2) and 300.435 (c)(2)(i) and CERCLA § 121 (f). The U.S. EPA supports the

changes in the selected remedy. The U.S. EPA concurrence is presented in a separate letter

dated DATE (Appendix A).

The LDEQ is the supporting agency for LAAP OU-010. The LDEQ has been consulted and

provided the opportunity to comment on this ESD in accordance with the NCP §§ 300.435 (c)(2)

and 300.435 (c)(2)(i) and CERCLA § 121 (f). The LDEQ supports the changes in the selected

remedy. The LDEQ concurrence is presented in a separate letter dated October 31, 2011.

(Appendix A). The ESD, its supporting information, and Administrative Record will be made

available for public review; once the ESD is completed, a newspaper public notice will be

published.

The U.S. EPA and the State of Louisiana, through the LDEQ, agree to accept the revised RBRGs

for 2A-DNT, 4A-DNT, and HMX based on appropriate toxicity values and the revised analyte

list for various LAAP OU-010 sub-areas.


8-1

8.0 STATUTORY DETERMINATIONS

The U.S. Army (as lead Federal Agency), with the concurrence of the U.S. EPA and LDEQ, has

determined that these significant changes comply with the statutory requirements of CERCLA §

121, 42 U.S.C. § 9621, are protective of human health and the environment, comply with Federal

and State requirements that are applicable or relevant and appropriate to the remedial action, are

cost-effective, and utilize permanent solutions and alternative treatment technologies to the

maximum extent practicable.

Because this remedy will result in hazardous substances, pollutants, or contaminants remaining

on-site above levels that allow for unlimited use and unrestricted exposure, a statutory review

will be conducted no less often than each five years to ensure that the remedy is, or will be,

protective of human health and the environment.


9-1

9.0 PUBLIC PARTICIPATION

This ESD will become part of the Administrative Record (NCP 300.825(a)(2)), which is

developed in accordance with Section 113 (k) of CERCLA, 42 U.S.C. § 9613 (k). The LAAP

repository is maintained with electronic copies of the administrative record at two local libraries;

Webster Parish Library in Minden, Louisiana and the Doyline Branch Library in Doyline,

Louisiana. Additionally, the administrative record is available for review at the Louisiana

Department of Environmental Quality, Public Records Center, Galvez Building Room 127, 602

N. Fifth Street, Baton Rouge, Louisiana, 70802. As required by NCP § 300.435(c)(2)(i)(B), a

Notice of Availability and a brief description of the ESD has been published in the local paper,

the Minden Press Herald, and the Shreveport Times (Appendix B). Likewise, the ESD, its

supporting information, and Administrative Record will be made available for public review;

once the ESD is completed, a newspaper public notice will be published.


10-1

10.0 AUTHORIZING SIGNATURE

I have determined that the remedy for the Installation-wide Groundwater (LAAP OU-010) as

modified by this ESD is protective of human health and the environment, and will remain so

provided the actions presented in this report area implemented as described above.

This ESD documents the significant changes related to the remedy for the Installation-wide

Groundwater (LAAP OU-010) at LAAP. These changes were selected by the U.S. Army with

the concurrence of the U.S. EPA and the LDEQ.

U.S. Army

Tables

Table 2-1Constituents of Concern

Record of Decision for LAAP-010 GroundwaterLouisiana Army Ammunition Plant

Doyline, Louisiana

Herbicides

Shallow Groundwater Human Health RiskConstituents of Concern

ExplosivesRDXHMX

2,4,6-Trinitrotoluene2,4-Dinitrotoluene2,6-Dinitrotoluene

2-Amino-4,6-Dinitrotoluene4-Amino-2,6-dinitrotoluene

1,3-Dinitrobenzene2,4-Dimethylphenol

1,2-DichloroethaneBenzene

DieldrinInorganics

ArsenicVolatiles

TetrachloroetheneTrichloroethene

Note:

Aluminum, iron, and manganese were deleted due to various lines of evidence indicating that they are naturally occuring on site and are

fmacronutrients required in humans for normal growth and health.

N:\CLIENT\LAAP\GFPR\Five Year Review\2010 FYR\ESD\Tables.xlsx(Table 2-1) 1 of 1 12/21/2011

TABLE 4-12007 ROD Constituent of Concern List by Area

Explanation of Significant DifferencesLAAP OU-010 Installation-wide Groundwater

Louisiana Army Ammunition PlantDoyline, Louisiana

Analyte

MCL

Calc (a)

2007 ROD Groundwater

Standard (mg/L) Area P BG-5 BG-8

Y-Line/OWL Area B Line E Line F Line G Line H

2,4,6-TNT Calc 2.83E-03

2,4-DNT Calc 1.24E-04

2,6-DNT Calc 1.24E-04

2-Amino-4,6-dinitrotoluene Calc 1.24E-04

4-Amino-2,6-dinitrotoluene Calc 1.24E-04

1,3-Dinitrobenzene Calc 3.62E-03

1,2-Dichloroethane MCL 5.00E-03

2,4-Dimethylphenol Calc 1.08E-04

Benzene MCL 5.00E-03

Dieldrin Calc 4.61E-06

HMX Calc 7.74E-04

RDX Calc 7.73E-04

Tetrachloroethene MCL 5.00E-03

Trichloroethene MCL 5.00E-03

Notes:

MCL - Maximum Contaminant LevelCalc - Calculated Risk-Based Monitoring Levels

(a) - The calculated Groundwater TBC levels represents the lesser of the risk-based standards for USEPA default residential adult exposures of carcinogenic risk = 1X10-6 or non-cancer hazard quotient = 1.0.

N:\CLIENT\LAAP\GFPR\Five Year Review\2010 FYR\ESD\Tables.xlsx(Table 4‐1) 1/1 12/21/2011

TABLE 5-1Contaminant of Concern List Comparison By Area

2007 ROD to 2011 ESD Explanation of Significant Differences

LAAP OU-010 Installation-wide Groundwater Louisiana Army Ammunition Plant

Doyline, Louisiana

Analyte 2007 ROD 2011 ESD 2007 ROD 2011 ESD 2007 ROD 2011 ESD 2007 ROD 2011 ESD 2007 ROD 2011 ESD 2007 ROD 2011 ESD 2007 ROD 2011 ESD 2007 ROD 2011 ESD 2007 ROD 2011 ESD

2,4,6-TNT

2,4-DNT

2,6-DNT

2-Amino-4,6-dinitrotoluene

4-Amino-2,6-dinitrotoluene

1,3-Dinitrobenzene

1,2-Dichloroethane

2,4-Dimethylphenol

Benzene

Dieldrin

HMX

RDX

Tetrachloroethene

Trichloroethene

Notes:

Shaded cell indicates contaminant of concern recommended for removal from list.

Line E Line G Line HArea P Line FBG-5 BG-8 Y-Line/OWL Area B


TABLE 5-2Updated Toxicity Values



Oral Dermal Oral Dermal Dermal RBRG RBRG MinimalGroundwater Cancer Cancer Non-Cancer Non-Cancer Permeability Based On Based On Value

COPC Slope Slope Reference Reference Constant Cancer Risk Non-Cancer RBRGFactor Factor Dose Dose (cm/hour) 1.00E-06 Hazard=1.0 (mg/L)

(mg/kg-day)-1 (mg/kg-day)-1 (mg/kg-day) (mg/kg-day) (mg/L) (mg/L)

2,4,6-TNT 3.00E-02 3.00E-02 5.00E-04 5.00E-04 1.07E-03 2.83E-03 1.82E-02 2.83E-032,4-DNT 6.80E-01 6.80E-01 NA NA 2.41E-03 1.24E-04 ND 1.24E-042,6-DNT 6.80E-01 6.80E-01 NA NA 2.41E-03 1.24E-04 ND 1.24E-042-Amino-4,6-dinitrotoluene 6.80E-01 6.80E-01 5.00E-04 5.00E-04 2.41E-03 1.24E-04 1.81E-02 1.24E-044-Amino-2,6-dinitrotoluene 6.80E-01 6.80E-01 5.00E-04 5.00E-04 2.41E-03 1.24E-04 1.81E-02 1.24E-041,3-Dinitrobenzene NA NA 1.00E-04 1.00E-04 2.05E-03 ND 3.62E-03 3.62E-032,4-Dimethylphenol 7.50E-01 7.50E-01 2.00E-02 2.00E-02 1.47E-02 1.08E-04 6.95E-01 1.08E-04Dieldrin 1.60E+01 1.60E+01 5.00E-05 5.00E-05 4.45E-02 4.61E-06 1.58E-03 4.61E-06HMX 1.10E-01 1.10E-01 5.00E-02 5.00E-02 1.14E-04 7.74E-04 1.82E+00 7.74E-04RDX 1.10E-01 1.10E-01 3.00E-03 3.00E-03 3.49E-04 7.73E-04 1.09E-01 7.73E-04Notes:Bold and shaded cells indicated updated toxicity values resulting in a new RBRG.


TABLE 5‐3Updated Risk Based Remedial GoalsExplanation of Significant Differences

LAAP OU‐010 Installation‐wide GroundwaterLouisiana Army Ammunition Plant

Doyline, Louisiana

CompoundInitial RBRG, based on

carcinogenic toxicity data (mg/L)

New RBRG, based on Hazard Index=1.0

(mg/L)

2‐Amino‐4,6‐dinitrotoluene 1.2E‐04 1.8E‐02

4‐Amino‐2,6‐dinitrotoluene 1.2E‐04 1.8E‐02

HMX 7.7E‐04 1.8


TABLE 5‐4Comparison of Risk Assessment Maximum Concentrations

to Updated Risk Based Remedial GoalsExplanation of Significant Differences Louisiana Army Ammunition Plant

Doyline, Louisiana

ChemicalNew RBRG (mg/L)

AreaMaximum

Concentration Units

Location of Maximum

ConcentrationDetection Frequency

Maximum Concentration Units

Location of Maximum


Maximum Concentration Units

Location of Maximum


Area P 1.40E‐01 mg/L GO109 8% 1.10E‐01 mg/L GO109 13% 1.35E+00 mg/L GO104 21%BG‐5 2.89E‐02 mg/L OW‐7 39% 3.15E‐02 mg/L OW‐7 22% 3.02E‐01 mg/L OW‐7 47%BG‐8 2.43E‐02 mg/L GO131 13% 2.32E‐02 mg/L GO029 20% 8.22E‐02 mg/L GO131 27%Area B NA ‐‐ ‐‐ ‐‐ 2.31E‐02 mg/L MW2‐12 8% 9.59E‐03 mg/L MW2‐12 8%Line C NA ‐‐ ‐‐ ‐‐ NA ‐‐ ‐‐ ‐‐ 4.68E‐03 mg/L GO221 19%Line E 1.54E‐01 mg/L GO240 43% 5.47E‐02 mg/L GO240 43% 7.00E‐02 mg/L GP241 43%Line F 5.71E‐03 mg/L GO246 54% 2.01E‐02 mg/L GO249 54% 3.92E‐01 mg/L GO249 54%Line G NA ‐‐ ‐‐ ‐‐ NA ‐‐ ‐‐ ‐‐ 3.06E‐01 mg/L GO224 25%Line H NA ‐‐ ‐‐ ‐‐ NA ‐‐ ‐‐ ‐‐ 2.80E‐02 mg/L GO228 44%Line S 3.81E‐04 mg/L GO237 22% 1.34E‐03 mg/L GO237 22% 2.28E‐03 mg/L GO237 78%Test Area 6 NA ‐‐ ‐‐ ‐‐ NA ‐‐ ‐‐ ‐‐ 7.67E‐04 mg/L GO248 9%Test Area 7 NA ‐‐ ‐‐ ‐‐ NA ‐‐ ‐‐ ‐‐ 2.94E‐04 mg/L GO253 22%

Notes:

mg/L ‐ milligrams per liter

NA ‐ Not Analyzed

RBRG ‐ Risk Based Remedial Goal

1.54E‐01 ‐ Bold and shaded cells indicate maximum concentration exceeds new RBRG

Maximum concentration values as presented in the Baseline Human Health and Ecological Risk Assessment (Shaw, 2005)

2‐Amino‐4,6‐Dinitrotoluene 4‐Amino‐2,6‐Dinitrotoluene HMX

1.80E‐02 1.80E‐02 1.80E+00


TABLE 6-1Groundwater Standards and Applicable Areas



2,4,6-TNT Calc 2.83E-03 c

2,4-DNT Calc 1.24E-04 c

2,6-DNT Calc 1.24E-04 c

2-Amino-4,6-dinitrotoluene Calc 1.80E-02 NC

4-Amino-2,6-dinitrotoluene Calc 1.80E-02 NC

1,3-Dinitrobenzene Calc 3.62E-03 NC

1,2-Dichloroethane MCL 5.00E-03 C

2,4-Dimethylphenol Calc 1.08E-04 C

Benzene MCL 5.00E-03 C

Dieldrin Calc 4.61E-06 C

HMX Calc 1.80E+00 NC

RDX Calc 7.73E-04 C

Tetrachloroethene MCL 5.00E-03 C

Trichloroethene MCL 5.00E-03 C

Notes:(a) - The Calculated Groundwater TBC levels represents the lesser of the risk-based standards for USEPA default residential adult exposures of carcinogenic risks = 1X10-6 or non-cancer hazard quotient = 1.0.MCL - Maximum Contaminat LevelCalc - Calculated Risk-Based Monitoring Levels

Line F Line G Line HBG-5 BG-8Y-Line/ OWL Area B Line EAnalyte MCL, Calc(a)

Groundwater Standard

(mg/L) Area P


Figures

TEXAS

LOUISIANA ~i'l

BARKSDALE AIR FCJlCE BASE

APPROXIMATE SCALE ------a 5 10 MILES

108923-A43

~W~·'ILOUISIANA ARMY AMMUNITION PLANT

FIGURE 1·1

SITE LOCATION MAP

FIVE YEAR REVIEW REPORT - 2010 GFPRlPBC NO. GS-10F..()[)48J

Appendix A U.S. EPA and LDEQ

Concurrence Documentation

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION 6

1445 ROSS AVENUE, SUITE 1200 DALLAS, TX 75202-2733

March 5, 20 12

Shaw Environmental and Infrastructure, Inc. Gen R. Landry, P.E. Cli ent Program Manager 4171 Essen Lane Baton Rouge, LA 70809

RE: Explanation of Significant Difterences (ESD) Louisiana Army Ammunition Plant Minden, Louisiana EPA ID Number LA0213820533 , Al No, 8993

Dear Mr. Landry:

This letter is to document our concurrence with the Explanati on of Significant Differences (ESD) submitted by your company on behalf of the U.S. Almy EnviroJUnental Center (USAEC), for the Louisiana Army Ammuni ti on Plant in Minden, Louisiana.

The proposed changes were reviewed by thc Environmental Protection Agency' s technical staff and were fo und acceptable, The document was also reviewed by the Louisiana Department of Environmental Quality, Underground Storage Tank and Remediation Division (LDEQ-USTRD) who ind icated their concurrence with this assessment by letter dated October 31 , 20 I I,

cc: Mr. Thomas F. Harris LDEQ-USTRD Administrator U,S. Army Installation Management Guard Louisiana National Guard Camp Minden Training Site

Sincerely,

121l 021 a ) {{ktl~') Samuel Colema ,P.E. ' Director Superfund Division

RICVCllH:.IIRtcyc la~ • • Prinlad wiTh Veoelable on 6ased InkJ on 100% Aecycl&d Poper (40% Po$toonSiJn'lOl)

CONCURRENCES

EXPLANATION OF SIGNIFICANT DIFFERENCES

Louisiana Army Ammunition Plant

Doyline, Webster and Bossier Parishes, Louisiana

EPA ID# LAD 0213820533

Louisiana Agency Interest No. 8993

By:ff~~ Bartolome J~A Remedial Project Manager (6SF-RL)

By: k~A- M-cU-f Susan Roddy, U.S. EPA

Ecological Risk Assessor (6SF -TR)

By: ~rof~. Jon Rauscher, U.S. EPA

Human Health Risk ses or (6SF-TR)

) £~

ounsel (6RC-S)

Date:

Date: / /3a /~O/:J.. -+-, ---,7<----'---'----'---

Date: e) ~ J?.~ (~

Date: 2j9fo(Z

Date: 07>fo/~2-•

Chief, S7,erf~nd Branch, 0 :~e of Regional Counsel (6RC-S)

By: [tl ~ trH--t' ' Date: d-/~ 4- (;;r-r .1

Date: c/b/;;L ~ ,

Date:_3

+-=-i ~ -+--'-1 I 1--_

Deputy Director Superfund Division (6SF-)

BOBBY -",\DAL 1.~..>\'(JI'r;'_'11

OCT 31 20\1

~tat£ of 1!.. ou ig ianil DEPARTMENT OF ENVmONMENTAL QI]AUTY

OFFICE OF ENVIRONMENTAL COMPLIANCE

Bartolome J. Canellas (6SF-RL) Remedial Project Manager Superfund Division US Environmental Protection Agency 1445 Ross A venue Dallas, Texas 75202

RE: Explanation of Significant Diffe rences Camp Minden; Agency Interest #8993 Doyline, LA

Dear Mr. Caiiellas,

PEC GY M . HATCH -.l\/l['I .. ln

The Louisiana Department of Environmental Quality, Underground Storage Tank and Remediation Division (LDEQ-USTRD) acknowledges receipt of this submittal, dated August 29, 2011, by Shaw Environmental and Infrastructure, Inc., on behalf of the US Army. It documents recommendations made in previous long-term monitoring reports and the 2010 Five-Year Review that proposed changes to the Record of Decision for OU-01 0 (site-wide groundwater). Those recommendations proposed modifications to the monitor well network, the li st of constituents of concern for various subareas, and updates to Risk Based Remedial Goals (RBRGs) for three constituents based upon revised toxicity values. Under separate cover, you sent EPA's Mr. John Rauscher's review and evaluation of the RBRG proposal, and the Department concurs with his assessment. With respect to our RECAP, the Department finds that the hierarchy used for identification of current toxicological evaluations and factors is acceptable. The Depanment concurs with the other recommendations.

We very much appreciate this opportunity to participate in evaluating the long-term monitoring program at Camp Minden.

All future correspondence in this matter should be in triplicate and addressed to

Mr. Thomas F. Harris, Administrator Underground Storage Tank and Remediation Division P. O. Box 4312, Baton Rouge, LA 70821-4312.

rO)~t Offill; 1 31''\1~1.! • U,l[tln Rougt', L"Ll j ~i:l n~1 ~(I~21·1.i l.l • Phonl: J..:!=i-.!J()-rJ'i • F;l,\: Jl;-Jlq-:,n~

\\,w,,, ,dL'1 I · {)ll j.~ i. lI1;! ~ll\

Letter to Mr. Bartolome 1. Cafiellas October 20, 20 I I Page 2

On such submittals please include the Agency Interest Number (8993) as it appears in the subject line of th is letter.

]f you have questions concerning this submittal please contact Mike Miller at (225) 219-3808.

Sincerely,

Thomas F. Harri s, Administrator Underground Storage Tank & Remediation Division

msm

c: Imaging - OW

Appendix B Newspaper Notice of ESD

MINDEN PRESSHHERALD· STATE OF LOUISIANA

PARISH OF WEBSTER

BEFORE ~, the undersigned authority, '. Ni l ~ . ~ '.:Jo ~~ SOb

deposes and says:

That he/she is the President of the Minden Press-Herald, a daily newspaper published in the City of Minden, Parish of Webster, Louisiana, and that the attached Notice was duly published in the said newspaper of the following dates: '

Sworn to and subscribed before me this 3D . day of (t"toQe~ ,2011

'i1dv~~ Nila P. Johnson, Pre aent .

203 Gleason St. • Minden, LA 71055. 318/377-1866 fax: 318/377-1895

www.press-herald.com

Public Notice Explanation of

Significant Difference

installation-wide Groundwater OU l()uisiana Army

Ammunition Plant

A review of the environmental restoration at the Installation wide groundwater OU, located on the Lo.uisiana Army Ammunitionf>lant (LAAP); now known 1:).s 9amp Minden, is required fbyfederal law every five years to ensure the

protection of human health. In the course of the completion of the First Five Year Revie"V\( .. for the Installation· wide grol.lr:JljV)later OU it was determined that sE3'1leral changes to the risk based remedial goals (RBRG) set forth in tM Record of Decision (ROD) were necessary. These changes are being made. to stay in compliance with updated EPA toxicity values. Additional minor changes are being incorporated to update groundwater monitoring well locations and analyte lists to reflect the results of ongoing groundw~ter monitoring and increase the monitoring program effectiveness. The risk management approach of Monitored Natural Attenuation as a passive approach

for achieving the Remedial Objectives for contaminated groundwater at LAAP remains unchanged. The remedial objectives of the restoration of a potential drinking water source to its maximum beneficial use and the prevention of direct human contact with COCs by on~site workers until RBRGs for drinking water are achieved remain unchanged.

This Public Notice serves as the announcement. that an Explanation of Significant Difference for the OU is in progress and the final report will be available at LAAP after completion. This ESD will become part of the Administrative Record (NCP 300.825(a)(2», which is developed in accordance with Section 113 (k) of

CERCLA, 42 U.S.C. § 9613 (k). The LAAP repository is maintained with electronic copies of the administrative record at two local libraries; Webster Parish Library in Minden, louisiana and the Doyline Branch library in Doyline, louisiana. Additionally, the administrative record is aVailable for review at the louisilina Department of Env.ironmental QUl:llity, Public Records Center, Galvez Building Room 127, 602 N. Fifth Street, Baton Rouge, Louisiana, 70802. Any interested parties are invited to contact LTC Troy Fontenot at (210) 466-1587 to provide comment.

October 20, 2011 Minden Press-Herald

s t d set for cord 0, ' (ROD) were.~~e'Ssary. These chal'l'ges are being made to stay in compliance with updated EPA toxicity values. Additional minor changes are being incorporated to update groundwater monitoring well locations and analyte lists to reflect the results of ~m~oing groundwater monitoring and inC(e9Se the m<mitor-

, effec- . he risk

apnitored

tem.lation

Q[hrQ[imt5 PROOF OF PUBLICATION

STATE OF LOUISIANA

PARISH OF CADDO

Before me, the undersigned authority, personally came and appeared

Altheas Critton personally known to me, Who being duly sworn, deposes and says that she is the

Assistant to the Classified Advertising Manager of The Times, and that the attached Advertisement published entitled:

Public Notice Explanation of Significant Difference Installationwide Groundwater au Louisiana Army Ammunition Plant

October 27,2011

Sworn to and subscribed before me this 2ih day of October, 2011

repository is maintained with electronic copies ofthe administrativerecord at two 101=al libraries; Webster Parish Li-brar Minden, Loui and the Doyline Branch library in D()yljne, Louisiana. AdditionallYl the administrative record is available for review at the Louisiana Department of Environmental Quality, Public Records Center, Galvez Building Room 127/,602 N. Fifth Street, Baton Rouge, Louisiana, 10802. A'1Y interested parties are invited to contact LTC Troy Fontenot at (210) 466-1587 to provide comment.

...".-,,'HJL.."'. NOTARY PUBLIC 60491 CADDO LOUISIANA

COMMISSION IS FOR LIFE

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