Other Edgewood Areas Study Area

Record of Decision Remedial Action at-the Western Shore Investigation Area (EAOEI2)

Final, August 2011 u.s. Army Garrison Aberdeen Proving Ground, Maryland

DISTRIBUTION RESTRICfION STATEMENT APPROVED FOR PUBLIC RELEASE DISTRffiUTION IS UNLIMITED #l1067S-A-7 FINAL

RECORD OF DECISION

REMEDIAL ACTION AT THE WESTERN SHORE INVESTIGATION AREA (EAOEI2) OTHER EDGEWOOD AREAS STUDY AREA ABERDEEN PROVING GROUND, MARYLAND

SUBMITTED BY:

ENVIRONMENTAL DIVISION DIRECTORATE OF PUBLIC WORKS U.S. ARMY GARRISON ABERDEEN PROVING GROUND EDGEWOOD, MARYLAND 21010

August 2011

DISlRIBUTION RESTRICTION STATEMENT APPROVED FOR PUBLIC RELEASE: DISTRIBTION IS UNLIMITED: #1067S-A-7 This page was' intentionally left blank. Record ofDecision Final OEA Western Shore I1fVestigation Area August 2011 Aberdeen Proving Ground, Maryland Pagei

TABLE OF CONTENTS

PART 1: DECLARATION...... ••.••.....•.....•...... •.••.••••.••..••..••.....••••..••.•.•....••••....1 1 SITE NAME AND LOCATION 1 2 STATEMENT OF BASIS AND PURPOSE 1 3 ASSESSMENT OF THE SITE ...... •..•...... •.•..•...•..••.••...•...... •..•••..••.••...•...... •...... ••.•.•2 4 DESCRIPTION OF THE SELECTED REMEDY 2 5 STATUTORY DETERMINATIONS.•••.••...... •....•.....••....•..•.....•....•..•.••••••.•....•.••••...•..•.•••.••.••.•.••.••••••3 6 DATA CERTIFICATION CIlECKLIST 4 7 AUTHORIZING SIGNATURES.....•.•.•...... •...... •.•...... •..•••.•••.•.•.••••.•...•.•.•.•....••••.•...•4 PART 2: DECISION SUMMARY 5 1 SITE NAME, LOCATION AND DESCRIPTION 5 2 SITE HISTORY AND ENFORCEMENT ACTIVITIES 5 3 PUBLIC/COMMUNITY INVOLVEMENT..•..•••..•••••••..•••.•.•.••••••••.••.••••.•.•.•••••.•.•••.••.••••..•••.•.•...... •• 11 4 SCOPE AND ROLE OF RESPONSE ACTION 12 5 SITE CHARACTERISTICS •.•.•.••....••••••...•.•..••.•••.•••••..••••••..•••.••.•••..•.•.••..•••.•.•.•••..••.•.•.••••••.•.••.....•...• 12

5.1 CONCEPTUAL SITE MODEL FOR WSIA 14 6 CURRENT AND POTENTIAL FUTURE LAND AND RESOURCE USES 23 7 SUMMARY OF SITE RISKS •.•..•...•.•.•.••••.•••.•••.•..•.••.•.••.••••..•••.••..•.•...... •...•.••.....•.•...... •.•.•••••...... •24

7.1 HUMAN HEALTH 24

7.2 ENVIRONMENT 30 8 REMEDIAL ACTION OBJECTIVES•...... •.•...... •...•.....•.•..•.•..•..•.••.•..•.•.•.•••••...•••...•..•...•••...••..31 9 DESCRIPTION OF ALTERNATIVES ..•.....•....•.....•...... •...... •...... •.••....•.•.••..•..•31

9.1 ALlERNATIVE 1: No ACTION 31

9.2 ALlERNATIVE2: LUCs 32 10 SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES 32

10.1 OVERALL PROTECTlON OF HUMAN HEALTH AND THE ENVIRONMENT 32

10.2 COMPLIANCE WITH APPLICABLE OR RELEVANT AND APPROPRIAlE REQUIREMENTS 32

10.3 LoNG-TERM EFFECTIVENESS AND PERMANENCE 34

lOA REDUCTION OF TOXICITY, MOBILITY, OR VOLUME THROUGH TREATMENT 34

10.5 SHORT-TERM EFFECTIVENESS 34

10.6 IMPLEMENTABILITY 34

10.7 COST 34

10.8 STAlE ACCEPTANCE 34

10.9 COMMUNITY ACCEPTANCE 34 Record ofDecision Final OEA Western Shore Investigation Area August 2011 Aberdeen Proving Ground, Maryland Page ii

11 PRINCIPAL TllREAT WASTES 34 12 SELECTED REMEDY.•••••••••.•...... •..•...•.•.•...... •....••••.•••••..••..•.••...... •..•...... •.•••....••.•••...... 35

12.1 DESCRIPTION OF lHE SELECTED REMEDy .35

12.2 LUC REMEDIAL DESIGN ••••••.••••••••••••••••••••....••...... •.••••••••••••••••••••••••••••••.••...••.•.•••••.•.••••••••••••••••••35

12.3 SUMMARY OFlHE RATIONALE FOR nmSELECfEDREMEoy 39

12.4 SUMMARy OF EsTIMATED REMEDY COSTS 40

12.5 EXPEcrED OUTCOMES OF SELEcrED REMEDY 40

12.6 PERFORMANCE STANDARDS FOR lHE SELECTED REMEDY 40 13 STATUTORY DETERMINATIONS 40

13.1 PROTECTION OF HUMAN HEALTII AND THE ENVIRONMENT .40

13.2 COMPLIANCE WITH APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS .42

13.3 COsT-EFFECTIVENESS : 42

13.4 UTILIZATION OF PERMANENT SOLUTIONS AND ALTERNATIVE TREATMENT TECHNOLOGIES TO

lHE MAxMUM EXTENT PRACTICABLE .42

13.5 PREFERENCE FOR TREATMENT AS A PRINCIPAL ELEMENT .42

13.6 CERCLA 121(C) FIVE-YEAR REVIEW REQUIREMENT 42 14 DOCUMENTATION OF SIGNIFICANT CHANGES 42 PART'3: RESPONSIVENESS SUMMARY 43 1 OVERVIEW 43 2 BACKGROUND ON COMMUNITY INVOLVEMENT 43 3 SUMMARY OF COMMENTS RECEIVED DURING THE PUBLIC COMMENT PERIOD AND AGENCY RESPONSES 45 PART 4: REFERENCES 48 RecordofDecision Final OEA Western Shore Investigation Area August 2011 Aberdeen Proving Ground, Maryland Page iii

LIST OF FIGURES

FIGURE 1. LOCATION OF OTHER EDGEWOOD AREAS IN ABERDEEN PROVING GROUND 6 FIGURE 2. LOCATION OF WESTERN SHORE INVESTIGATION AREA WITHIN OTHER EDGEWOOD AREAS 7 FIGURE 3. SITE FEATURES WITHIN THE WESTERN SHORE INVESTIGATION AREA 9 FIGURE 4. WESTERN SHORE INVESTIGATION AREA SURFACE SOn.. SAMPLING LOCATIONS 17 FIGURE 5. WESTERN SHORE INVESTIGATION AREA SURFACE WATER AND SEDIMENT SAMPLING LOCATIONS .18 FIGURE 6. EXTENT OF PROHffiITION ON REsIDENTIAL LAND USE IN WESTERN SHORE INVESTIGATION AREA 37

FIGURE 7. SAMPLE NEWSPAPER ADVERTISEMENT 44

LIST OF TABLES

TABLE 1. SUMMARY OF RISKS ASSOCIATED WITH ExpOSURES IN THE WSIA UNDER CURRENT AND FUIURE

LAND USE CONDITIONS 26

TABLE 2. SUMMARY OF RIsKS ASSOCIATED WITH EXPoSURES IN THE WSIA UNDER FUTURE LAND USE CONDITIONS 27

TABLE 3. REMEDIAL ALTERNATIVE EVALUATION CRITERIA 33 TABLE 4. DETAILED COSTS FOR THE SELECTED REMEDY 41 RecordofDecision Final OBA Western Shore I11Vestigation Area August 2011 Aberdeen Proving Ground, Maryland Page tv

ACRONYMS AND ABBREVIATIONS

AEDB-R Anny Environmental Database - Restoration AOC area ofconcern APG Aberdeen Proving Ground ARAR applicable or relevant and appropriate requirement bgs below ground surface BRAC Base Realignment and Closure BTAG Biological Technical Assistance Group BTEX benzene, toluene, ethylbenzene, and xylene CI2-SD Cluster 12 sediment CI2-SS Cluster 12 surface soil CI2-SW Cluster 12 surface water CERCLA Comprehensive Environmental Response, Compensation and Liability Act cac chemical of concern COPC chemical ofpotential concern COMAR Code ofMaryland Regulations CSM Conceptual Site Model 4,4'-DDD 4,4'-dichlorodiphenyldichloroethane 4,4'-DDE 4,4'-dichlorodiphenyldichloroethene 4,4'-DDT 4,4'-dichlorodiphenyltrichloroethane DDTr 4,4'-DDT + 4,4'-DDE + 4,4'-DDD DPT direct push technology EA EA Engineering, Science, and Technology, Inc. FFA Federal Facility Agreement FFS Focused Feasibility Study GIS Geographic Information System GP General Physics Corporation llliRA Human Health Risk Assessment HI hazard index HQ hazard quotient IRP Installation Restoration Program LECR lifetime excess cancer risk RecordofDecision Final OEA Western Shore llTVestigation Area August 2011 Aberdeen Proving Ground, Mary/and Page v

LUC land use control MCL Maximum Contaminant Level MDE Maryland Department ofthe Environment msl mean sea level Ilglkg micrograms per kilogram IlgIL micrograms per Liter mglkg milligrams per kilogram NCP National Oil and Hazardous Substances Pollution Contingency Plan NPL National Priorities List OEA Other Edgewood Areas OEA-GF Other Edgewood Areas G-Field O&M operation & maintenance OSWER Office of Solid Waste and Emergency Response PAH polycyclic aromatic hydrocarbon PCB polychlorinated biphenyl RAB Restoration Advisory Board RAO remedial action objective RCRA Resource Conservation and Recovery Act RD remedial design RFA RCRA Facility Assessment RI remedial investigation ROD record ofdecision RSL Regional Screening Level SARA Superfimd Amendments and Reauthorization Act SVOC semivolatile organic compound SWMU Solid Waste Management Unit TRV toxicity reference value USAEC U.S. Anny Environmental Command (formerly the U.S. Army Environmental Center) USAEHA U.S. Anny Environmental Hygiene Agency (now the U.S. Army Center for Health Promotion and Preventative Medicine [USACHPPMD USATHAMA U.S. Army Toxic and Hazardous Materials Agency (now the U.S. Army Environmental Command) Record ofDecision Final OKA Western Shore Investigation Area August 2011 Aberdeen Proving Ground, Maryland Page vi

USEPA u.s. Environmental Protection Agency UST underground storage tank UXO unexploded ordnance VOC volatile organic compound WHF­ H-Field groundwater monitoring well designation WSIA Western Shore Investigation Area WS-MD-l composite soil sample designation WS-SD Western Shore sediment WS-SO-l grab soil sample designation WS-SS Western Shore surface soil WS-SW Western Shore surface water RecordofDecision Final OEA Western Shore Investigation Area August 2011 Aberdeen Proving Ground, Maryland Pagel

RECORD OF DECISION REMEDIAL ACTION AT THE WESTERN SHORE INVESTIGATION AREA (EAOE12) OTHER EDGEWOOD AREAS STUDY AREA ABERDEEN PROVING GROUND, MARYLAND

August 2011

PART 1: DECLARATION

1 SITE NAME AND LOCATION

The Western Shore Investigation Area (WSIA), located within the Edgewood Area of Aberdeen Proving Ground (APG), Maryland has been designated for Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) response action to address the impact of historical waste management practices. The WSIA lies in the western portion of the Other Edgewood Areas (OEA) Study Area, along the Gunpowder River. Included in the WSIA are open space/undeveloped areas, the western portions of military test ranges H-Field and I-Field, the northwestern portion of J-Field, and six other sites identified for investigation, and listed below. U.S. Army CERCLA response actions are tracked in the Army Environmental Database-Restoration (AEDB-R). The six WSIA sites, corresponding to AEDB-R Number EAOE12, are:

AEDB-R No. EAOE12 Sites:

~ H-Field Pre-World War II (WWII) Artillery Target Area 1 ~ H-Field Building E1464 Septic Tank Site ~ H-Field Building E1467 Storage Site ~ H-Field Washrack Wastewater Site ~ H-Field Groundwater Supply Well ~ Debris Mounds

CERCLA activities at APG are being conducted under a Federal Facility Agreement (FFA) signed by the U.S. Environmental Protection Agency (USEPA) and the U.S. Department of the Army (Army) on March 27, 1990. The USEPA Superfund Site Identification Number fs MD 2210020036. This Record of Decision (ROD) is listed under OU-27 in USEPA's database.

2 STATEMENT OF BASIS AND PURPOSE

This ROD presents the remedy selected by the Army and the USEPA Region III to address the WSIA within the Edgewood Area. The Selected Remedy for the WSIA is Land Use Controls (LUCs), which was chosen in accordance with CERCLA, as amended by the Superfund Amendments and Reauthorization Act (SARA), and, to the extent practicable, the National Oil and Hazardous Substances Pollution Contingency Plan Record ofDecision Final OEA Western Shore Investigation Area August 2011 Aberdeen Proving Ground, Maryland Page 2

(NCP). TIris decision is based on the Administrative Record for the WSIA.

The State ofMaryland concurs with the selected remedy.

3 ASSESSMENT OF THE SITE

Potential exists for risk to human health ifno remedial action is undertaken.

Field investigations identified only sporadic and isolated detections of contaminants within the WSIA but various metals are present in surface media at concentrations higher than background. These constituents do not pose unacceptable risk to future military/industrial workers or the ecosystem. However, the investigation data, while sufficient to evaluate risk to military/industrial receptors and the environment, are not sufficient to evaluate risk for residential land use. Therefore, without further collection ofdata, the WSIA would not be suitable for unlimited use and unrestricted exposure (e.g., housing, elementary and secondary schools, child care facilities, playgrounds, and other residential land use). Consequently, an active remedial action for the entire WSIA is not warranted based on projected future land use (industrial/military). Instead, LUCs preventing future residential land use are warranted for the entire WSIA.

The response action selected in this ROD is necessary to protect the public health or welfare, or the environment from actual or threatened releases of hazardous substances into the environment

4 DESCRIPTION OF THE SELECTED REMEDY

The Selected Remedy for the WSIA is LUCs. The detailed approach and methodology will be specified in an LUC Remedial Design (RD) document.

~ Land-Use Controls: LUCs will be implemented at the WSIA to prevent future residential land use (Le., housing, elementary and secondary schools, child care facilities, playgrounds, and other residential land use) until further sampling conducted at a spacing designed to assess risks associated with residential use of the site demonstrates that there are no unacceptable risks associated with unlimited use and unrestricted exposure. Because the potential presence of unexploded ordnance (UXO) will still exist at the WSIA, existing Installation safety procedures and policies related to UXO will be followed for any soil disturbances at the WSIA. TIris is to ensure adequate protection ofworkers and military personnel at the WSIA. The site map on Figure 6 shows the boundaries where the LUC objectives will be applied and maintained.

The RD will be submitted consistent with the RD schedule provisions of the FFA and will specify the details of LUC implementation and maintenance (including periodic inspections).

The Army will be responsible for implementing, maintaining, reporting on and enforcing the LUCs described in this ROD and the subsequent RD. As part of the Army's inspection and reporting responsibilities, periodic reviews of the restrictions and Record ofDecision Final OEA Western Shore Investigation Area August 2011 Aberdeen Proving Ground, Maryland Page 3

objectives outlined above will be undertaken and a review report will be submitted to USEPA and the Maryland Department of the Environment (MOE). The LUCs will include implementation through the APG Master Planning System with Geographic Information System (GIS) support. As set forth in this ROD, the Army will not modify or terminate LUCs or implementing actions without prior agreement of USEPA, after conferring with MOE. The Army will seek prior concurrence from USEPA and MOE before taking any action that would disrupt the effectiveness ofthe LUCs.

If the Army transfers property in the areas addressed by this ROD, the Army will place a deed notification in the local property record that describes the restrictions on site activities and states that this notification is filed with the appropriate agencies, so that current and future property owners will be aware of these restrictions. Specific deed notification language and the appropriate agencies will be identified in the approved RD. While the Army retains ultimate responsibility for LUC enforcement, the Army may require the transferee or lessee in cooperation with other stakeholders to assume responsibility for LUC implementation actions. Third-party LUC responsibility will be incorporated into pertinent contractual, property and remedial documentation, such as a purchase agreement, deed, lease and RD addendum.

To the extent permitted by law, a transfer deed shall require the LUCs imposed as part of a CERCLA remedy to run with the land and bind all property owners and users. If the Army intends to transfer ownership of any site, the Army may, if Federal and/or State law allows, upon transfer of fee title, grant the State an environmental covenant or easement that would allow the State to enforce LUC terms and conditions against the transferee(s), as well as subsequent property owner(s) or user(s) or their contractors, tenants, lessees or other parties. This covenant will be incorporated by reference in the transfer deed and will run with the land in accordance with State realty law. This State enforcement right would supplement, not replace, the Army's right and responsibility to enforce the LUCs.

5 STATUTORY DETERMINATIONS

This remedial response meets the requirements of CERCLA Section 121 and, to the extent practicable, the NCP. The Selected Remedy is protective of human health and the environment; provides long- and short-term effectiveness; complies with all Applicable or Relevant and Appropriate Requirements (ARARs); is cost-effective; and utilizes permanent solutions to the maximum extent practicable.

The remedy selected for this au does not satisfy the statutory preference for treatment as a principal element of the remedy for the following reasons. The contaminants found at the site are only found sporadically, so that it would be impractical to attempt to use treatment to address the contaminated areas. Furthermore, since there is no risk to receptors under current and reasonably anticipated military/industrial land use, treatment is not necessary to protect these receptors.

Because this selected remedy will result in hazardous substances, pollutants or contaminants remaining on site at levels that do not allow for unlimited use and Record ofDecision Final OBA Western Shore Investigation Area August 2011 Aberdeen Proving Ground, Maryland Page 4 unrestricted exposure, the entire WSIA will be included in the consolidated five-year CERCLA remedy reviews of the Edgewood Area's National Priorities List (NPL) sites, to ensure that the remedy is, or will be, protective of human health and the environment.

6 DATA CERTIFICATION CHECKLIST

The following information is included in the Decision Summary, Part 2 of this ROD. Additional information can be found in the Administrative Record file.

~ Chemicals of concern (COCs) and their respective concentrations (Decision Summary, Section 5).

~ Baseline risk represented by the COCs (Decision Summary, Section 7).

~ The absence of source materials constituting principal threats (Decision Summary, Section 11).

~ Current and reasonably anticipated future land use assumptions and current and potential future beneficial uses of groundwater used in the baseline risk assessment and ROD potential land uses that will be available as a result of the Selected Response Actions (Decision Summary, Section 6).

~ Potential land and groundwater use that will be available at the site as a result of the Selected Remedy (Decision Summary, Section 12.5).

~ Estimated capital, annual O&M, and total present worth costs, and the number of years over which the response cost estimates are projected (Decision Summary, Section 9).

~ Key factor(s) that led to selecting the remedial response (i.e., describes how the Selected Response Actions provide the best balance of tradeoffs with respect to the balancing and modifying criteria, highlighting criteria key to the decision) (Decision Summary, Section 10).

7 AUTHORIZING SIGNATURES

The appropriate approval authority for this action is the APG Garrison Commander. ­

_DJ.k M. odv"----_'''_H-J'_'_ Orlando W. Ortiz Date Colonel, MI Garrison Commander

/ /'d ~d~~j-g.~:::::::"":::::===== ----J'-4~~~~~~rY( Ronal . Borsellino Dir or, Hazardous Site Cleanup Division U.. Environmental Protection Agency, Region III

RecordofDecision Final OEA Western Shore Investigation Area August 2011 Aberdeen Proving Ground, Maryland PageS

PART 2: DECISION SUMMARY

1 SITE NAME, LOCATION' AND DESCRIPTION

APG is an approximately 72,500-acre Army installation located in southern Harford and southeastern Baltimore counties, on the western shore of the upper Chesapeake Bay (Figure 1). The installation is bordered to the east and south by the Chesapeake Bay; to the west by Gunpowder Falls State Park, the Crane Power Plant, and residential areas; and to the north by the City of Aberdeen and the towns of Edgewood, Joppatowne, Magnolia, and Perryman. The Bush River divides APG into two areas: the Edgewood Area to the west and the Aberdeen Area to the east. OEA is in the Edgewood Area part of the APG NPL Site, USEPA Superfund Site Identification Number MO 2210020036. The site owner and lead.agency is the Army, with USEPA as the lead regulatory agency and MOE as the supporting regulatory agency.

The OEA lies in the southern portion of the Edgewood Area of APG on the Gunpowder Neck peninsula (Figure 1). The OEA consists of military test ranges and Pooles Island, located south of the peninsula in the Chesapeake Bay. The total land area of the OEA is approximately 5,068 acres. The WSIA lies within the western portion of OEA along the Gunpowder River (Figure 2). Included within the 334-acre parcel are the western portions of military test ranges H-Field and I-Field, and the extreme northwestern portion of J-Field (Figure 3). Since as early as 1918, these range fields have been used for military testing and training activities, including use as impact areas for mortar and artillery ordnance.

2 SITE mSTORY AND ENFORCEMENT ACTIVITIES

Established as the Ordnance Proving Ground in 1917, the Aberdeen Area of the installation became a fonnal military post, designated as APG, in 1919. Traditionally, APG's primary mission involved the testing and development of weapon systems, munitions, vehicles and a wide variety of military support materiel. The Edgewood Area (fonnerly Edgewood Arsenal) was appropriated by presidential proclamation in 1917 and has since been a site of laboratory research; field testing of chemical materiel and munitions; pilot-scale manufacturing; production-scale chemical agent manufacturing and related test, storage and disposal operations (U.S. Army Toxic and Hazardous Materials Agency [USATHAMA], 1983).

During 1984 and 1985, APG was evaluated as a potential NPL site. In 1985, the Edgewood Area of APG was proposed for inclusion on the NPL; and it was listed in 1990. In 1986, between the time of the proposed listing and the final listing, a Resource Conservation and Recovery Act (RCRA) corrective action permit (MD3-21-002-1355) was issued by the USEPA Region III to address solid waste management units (SWMUs) in the Edgewood and Aberdeen areas ofAPG. As required by the RCRA permit, the U.S. Army Environmental Hygiene Agency (USAEHA) perfonned a RCRA Facility Assessment (RFA) for the Edgewood Area The RFA identified sites in the Edgewood

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Area that were either SWMUs or areas of concern (AOCs) for potential contamination (USAEHA, 1989). After the final NPL listing of the Edgewood Area in 1990, further investigations were conducted in accordance with CERCLA under the 1990 FFA with USEPA.

The FFA identified specific Study Areas within the Edgewood Area including Canal Creek, O-Field, J-Field, Carroll Island, Graces Quarters, Westwood, Lauderick Creek, and the Bush River Study Areas. The Edgewood Area SWMUs and AOCs not specifically listed above were grouped and designated the OEA.

In 1991, the Generic Work Plan for Remedial Investigation (RI) work at the Edgewood Area was published and initially divided known potential source areas in the OEA into 31 "clusters" of sites by geographic area. Because of the very large size of the OEA and the need for an integrated approach, a Strategic Work Plan developed in 1999 organized the 31 OEA clusters by watershed/drainage basins into eight Investigation Areas. In 2009, the U.S. Army Environmental Command (USAEC) reduced the number of OEA clusters to 27. Clusters 43 and 52 (within the Swaderick-Watson Creek Investigation Area) and Clusters 45 and 49 (within the Coopers Creek Investigation Area) were removed from the list of AEDB-R sites requiring investigation under the CERCLA program because of their use as ranges with no documented history or evidence ofdisposal practices or use of hazardous materials at the sites. The WSIA contains one cluster of sites numbered 12 and includes only the Western Shore drainage basin.

Field investigations to support the WSIA RI were conducted in several phases from 1996 to 2008. Activities included historical document and aerial photograph reviews, installation of wells and direct push technology (OPT) locations to monitor the groundwater, and the sampling of groundwater, surface water, sediment, and soil. The WSIA Focused Feasibility Study (FFS) (General Physics [GP], 20 11 b) was finalized in April 2011.

3 PUBLIC/COMMUNITY INVOLVEMENT

CERCLA Sections 113 (k) (2) (B) and 117, the NCP, and Department of Defense and Army policy require the involvement of the local community as early as possible and throughout the Installation Restoration Program (IRP) process. To accomplish this, APG is conducting monthly Restoration Advisory Board (RAB) meetings and periodic public meetings at each decision point in the CERCLA remedial process. The RAB membership is comprised of Army, USEPA and MOE, and local community members. Progress of the WSIA RI has been disCussed annually at RAB meetings. since 1996. Remedial alternatives for the WSIA were initially briefed during the June 2009 RAB meeting. The Proposed Plan for the WSIA was made available to the public on June 8, 2011. The Administrative Record, which contains the information used to select the remedial response, may be found at the Aberdeen and Edgewood branches of the Harford County Public Library and at the Miller Library at Washington College. The notice of the availability of these documents was published in The Aegis and The Cecil Whig on June 8, 2011, and Kent County News, The Avenue News, and East County Times on June 9, 2011. A public meeting was held on June 14, 2011. The public comment period was held Record ofDecision Final OBA Western Shore Investigation Area August 2011 Aberdeen Proving Ground, Maryland Page 12 from June 8 to July 7, 2011. Responses to the public comments received during this period are included in the Responsiveness Summary, Part 3 ofthis ROD. 4 SCOPE AND ROLE OF RESPONSE ACTION

This ROD addresses the fmal response action for surface media (Le., soil, surface water, and sediment) within the WSIA. Based on available groundwater data collected during the RI, there is no evidence of groundwater plumes or contributing sources of contamination within WSIA groundwater. Thus, constituents in groundwater did not warrant additional evaluation or risk assessment under CERCLA, and a response action addressing WSIA groundwater is not necessary. Final remedial response actions for the remaining seven OEA Investigation Areas (Le., Gun Club Creek, Doves Cove, Western Shore, Coopers Creek, Swaderick-Watson Creek, Maxwell Point, and Boone Creek Investigation Areas) are being evaluated, proposed, and implemented under separate FFS, Proposed Plan, and ROD documents.

The Army is selecting LUCs for the WSIA at this time to prevent future residential land use (Le., housing, elementary and secondary schools, child care facilities, playgrounds, and other residential land use). For the WSIA, no additional response action will be taken. The WSIA will remain "as is," with no containment, removal, treatment, or other mitigating measures. Because the potential presence ofUXO will still exist at the WSIA, existing Installation safety procedures and policies related to UXO will be followed for any soil disturbances at the WSIA in the future. This is to ensure adequate protection of workers and military personnel at the WSIA. Since RI sampling was conducted at a spacing designed for industrial land use, additional sampling would be necessary if the land were to be used for residential use. LUCs, as described above, will be implemented unless and until further sampling conducted at a spacing designed to ass~ss risks associated with residential land use indicates that there are no unacceptable human health risks associated with unlimited use and unrestricted exposure. 5 SITE CHARACTERISTICS

The WSIA lies on the southwestern edge ofthe Gunpowder Neck Peninsula, and includes the Western Shore drainage basin (approximately 334 acres). The topography of the WSIA is relatively flat (averaging 20 feet above mean sea level (msl)) and slopes gently toward the west-southwest to wetlands bordering the Gunpowder River shoreline. Surface water runoff generally flows from the eastern upland areas to the west toward the Gunpowder River and associated marshes. Surface water and sediment samples were collected mostly downgradient of the WSIA and within drainage ditches to assess potential contaminant migration pathways. Selected surface soil samples were also collected in drainage swales within the WSIA.

The WSIA consists primarily of four habitat types. Approximately 60 percent ofthe area is mixed hardwood forests with woody vegetation understory, while 20 percent of the area consists of freshwater/brackish marshes. Approximately 13 percent of the area is mowed and developed fields. Mixed hardwood makes up the remaining seven percent of the area. The forested areas represent a transition area between the oak-pine and oak­ chestnut forest regions of the eastern United States, and consist of a variety of deciduous Record ofDecision Final OEA Western Shore Investigation Area August 2011 Aberdeen Proving Ground, Maryland Page 13

species characteristic of these regions. The wetlands are dominated by estuarine and palustrine emergent wetlands, with small areas offorested wetlands. The shoreline ofthe Investigation Area has been impacted by erosion caused by storms and hurricanes.

The forest, field and wetland habitats at the WSIA support a variety of wildlife and vegetation. Currently, there are no known occurrences of endangered flora or fauna species in the WSIA. Bald eagles, previously listed under Federal protection status as threatened, are known to forage in and around the WSIA. The closest known active nesting areas are within the Boone Creek Investigation Area, approximately 2,500 feet east of the WSIA and within the Swaderick-Watson Creek Investigation Area, approximately 2,000 feet north ofthe WSIA.

Tulip, oak, maple, sweet gum and pine trees dominate secondary growth forest vegetation at the WSIA. Typical forest species of the area include red fox, gray squirrel, white-tailed deer, woodpecker, crows and a variety of songbirds. Shrubs and native grasses are found in the open fields. Field species include field mice, voles, cottontail rabbits, bobwhites, mourning doves, killdeer, hawks and songbirds.

Wetland plants common to the palustrine emergent areas include phragmites, cattails and rushes. Estuarine emergent species include phragmites, cordgrass, three squares, and rushes. Wetland species include muskrats, turtles, snakes, great blue herons, puddle and diving ducks, and a variety of shorebirds, including spotted sandpiper, and rails. Estuarine fish that are expected to live in the Gunpowder River include largemouth and striped bass, carp, white and yellow perch, bluefish, catfish, sunfish, Atlantic silverside, and eels (ICF,.l997).

Surface soil in the WSIA mainly consists of sandy loams with varying amounts of silts. Surface soil and sediments in the vicinity of marshes, low-lying floodplain areas, and the shorelines adjacent to the Gunpowder River contain abundant organics. The soil includes peat, organic-silt, and organic clay with varying sand content. Sediments, which are present along the WSIA shoreline adjacent to the Gunpowder River, are silty-sand, sand, and gravelly sands.

The WSIA lies within Harford County, Maryland on the unconsolidated sediment of the physiographic province, the Atlantic Coastal Plain. In the Coastal Plain, unconsolidated sedimentary strata consisting of clay, silt, sand and gravel of Cretaceous, Tertiary and Quaternary age (144 million years ago to recent) unconformably overlie the crystalline basement rocks of Precambrian (more than 570 million years ago) and early Paleozoic age. The sediment of the Atlantic Coastal Plain, deposited by actions of streams, rivers, and seas, forms a wedge-shaped body that thickens southeastward.

The surficial (water table) aquifer underlying the WSIA does not qualify as a source or potential source of drinking water, based on hydraulic parameters under both Federal and State aquifer classifications. The surficial aquifer is currently not used as an industrial water supply. RecordofDecision Final OEA Western Shore 111Vestigation Area August 2011 Aberdeen Proving Ground, Maryland Page 14

The vadose (unsaturated) zone or depth to groundwater within the WSIA ranges from 5 to 9 feet below grade and contains sandy-silt with interbedded silty-clay or clayey-silt lenses. The individual silt and sand lenses range from 1 to 10 feet thick. The groundwater-bearing unit ranges in thickness from 1 to 19.5 feet thick in the upper portion to 2.5 to 31 feet thick in the lower portion. The specific sediments that comprise the groundwater bearing units include mainly well-sorted sands in the upper portion and silty-sands to gravels in the lower portion. A continuous semi-permeable layer, consisting of small scale interfingered beds of silt, sandy-silt, and silty-sand, divides the groundwater-bearing units into an upper and lower portion which thins to the southwest direction. This semi-permeable layer averages approximately 10 to 11 feet thick. A dense, silty-clay unit encountered during direct push technology activities and drilling lies immediately below the shallow groundwater-bearing units and appears to be a confining unit. In general, high groundwater levels occur near topographically elevated areas where the shallow groundwater received recharge. Groundwater flows from the eastern portion of the WSIA boundary to the west-southwest with a decreasing groundwater gradient on the west side due to the thinning of the groundwater-bearing units as they approach the wetlands bordering the Gunpowder River. The average groundwater gradient in the predominant southwest direction was 0.01. Groundwater then discharges through the sediment to the surface water ofthe Gunpowder River.

Field investigations to support the WSIA RI were conducted in several phases from 1996 to 2008 (GP, 2011a). Activities included historical document and aerial photograph reviews, a soil gas survey, installation of wells to monitor groundwater, and environmental media (i.e., groundwater, surface water, sediment, and surface soil) sampling to identify the nature and extent of contamination. RI samples were analyzed for Target Analyte List inorganics and Target Compound List volatile organic compounds (VOCs), semivolatile organic compounds (SVOCs) and pesticides/polychlorinated biphenyls (PCBs), explosive-related compounds, chemical agent degradation products, general chemical constituents and physical properties, and radiological parameters.

The following Section 5.1 provides discussions of primary sources and release mechanisms, and secondary sources and release mechanisms for the WSIA sites.

5.1 Conceptual Site Model for WSIA

A Conceptual Site Model (CSM) is an integrated representation of the physical and environmental characteristics of a site, as well as the complete, potentially complete, and incomplete exposure pathways between sources of contaminants at a site and potential human and environmental receptors. For a potential risk to be associated with a contaminant release, a complete pathway from the source to a receptor must exist, and the receptor must be present when the contamination arrives or still exists. In addition, the CSM documents when an uncertainty is or is not significant, i.e., illustrates why data collection activities are or are not needed to support the decision-making process. The CSMs developed for the WSIA are based on the data that are presented in the RI documentation and contain detailed analytical data for all of the environmental media samples taken in the characterization of the WSIA. The RI document is available in the Record ofDecision Final OEA Western Shore Investigation Area August 2011 Aberdeen Proving Ground, Mary/and Page 15

Administrative Record. Prinulry Sources and Release Mechanisms The primary sources that had been suspected and evaluated in the RI for the WSIA included testing, training, and firing activities, waste dumping, material storage sites, and wastewater treatment systems.

Primary release mechanisms for contaminant transport at the WSIA sites were: (a) shoreline erosion with potential for release of constituents to Gunpowder River sediment and surface water, and (b) spillage/deposition to surface soil and leaching of constituents from waste to adjacent or underlying soil, then infiltration of contamination through the vadose zone to the groundwater. Secondary Sources and Release Mechanisms Secondary sources include surface and subsurface soil in the WSIA. Secondary release mechanisms include volatilization/dust generation; biotic uptake; stormwater runoff and erosion of soil and/or sediment during precipitation events, and transport to marshes, and eventually the Gunpowder River; and leaching for subsurface soil. R1 Data Sumnuuy During the RI, groundwater samples were obtained from seven monitoring wells and 30 DPT locations within the WSIA. Along with 54 surface soil and 19 subsurface soil samples, a total of 18 sediment samples and 36 surface water samples were collected at the WSIA to evaluate the potential for historical waste management activities to impact aquatic media. Although contaminants were detected throughout the WSIA in various surface media and groundwater, none exhibited a consistent and elevated pattern to distinguish any source(s) or pattern(s) of migration within the WSIA.

Explosive-related compounds (e.g., 2-nitrotoluene, HMX, RDX) and chemical agent degradation products (e.g., thiodiglycol) were detected in WSIA surface water and soil samples, but none of the concentrations exceeded any available RI comparison criteria. Metals and pesticides were the primary constituents detected in surface water, sediment, and surface soil, in excess of RI comparison criteria. A few VOCs were also detected at low level concentrations, but most were either below Maximum Contaminant Levels (MCLs) or Regional Screening Levels (RSLs), or qualified as "]" (estimated value below the reporting limit) or "B" (detected in laboratory blanks) during the data validation process.

The results of four rounds of groundwater monitoring well samples (28 samples) and 65 DPT samples indicated VOCs, SVOCs, pesticides, and metals were the primary constituents detected in groundwater. Most detections of VOCs and SVOCs were found in two groundwater monitoring wells (H-Field wells WHF-05 and WHF-07) and DPT groundwater locations downgradient of three former petroleum underground storage tanks (USTs) associated with Building EI464. BTEX were the predominant VOCs detected above RI comparison criteria. All exceeded the Regional Screening Levels (RSLs) (USEPA, 2008) for tap water and benzene and toluene exceeded both the RSLs Record ofDecision Final OBA Western Shore Investigation Area August 2011 Aberdeen Proving Ground, Mary/and Page 16 and maximum contaminant levels (MCLs) (USEPA, 2008a). The maximum concentrations occurred in WHF-05 when sampled on August 27, 2003. Benzene and toluene were detected at maximum concentrations of 3,600 micrograms per Liter (JJ.g/L) and 9,600 JJ.g/L, respectively. Ethylbenzene was detected at a concentration of 390 JJ.g/L and xylenes were detected at a maximum concentration of 5,200 JJ.g/L. WHF-07 contained maximum concentrations of benzene at 650 JJ.g/L, toluene at 960 JJ.g/L; and ethylbenzene and total xylenes at 52 JJ.g/L and 510 J.LS!L, respectively. BTEX constituents were detected in WHF-05 and WHF-07 during subsequent sampling events at lower concentrations. However, at WHF-07 benzene and ethylbenzene concentrations still exceeded the RSL values, and benzene levels exceeded the MCL value.

With the exception of the BTEX results, only two organic compounds exceeded primary MCLs (Le., 1,1,2-trichloroethane and trichloroethene) and only three inorganic compounds (i.e., aluminum, arsenic, and manganese) exceeded reference background levels and MCLs in monitoring wells. None of the organic compound concentrations were duplicated or had increased concentrations above MCLs during subsequent sampling rounds. The sporadic and isolated detections of low-level chlorinated VOC concentrations (maximum of 10 JJ.g/L) in groundwater occurred at H-Field well WHF-05 during only one round. The DPT groundwater samples surrounding these wells did not contain contaminants and did not reveal any contaminant sources or migration. The vast majority of the inorganic samples were not detected in the filtered (dissolved) samples. The majority of the elevated total aluminum, arsenic, and manganese concentrations all had corresponding elevated total dissolved solids, indicating the samples were turbid from fme-grained material within the wells. In addition, none of these metals showed a pattern of migration within the WSIA. At a February 4, 2004 meeting with USEPA and MDE (APG, 2004) groundwater data from the seven monitoring wells and 29 DPT locations within the WSIA were reviewed. The regulatory agencies and the Army agreed that the area of BTEX contamination (above RI comparison criteria) in groundwater and soil downgradient of Building E1464's former USTs would be addressed under RCRA. Based on the screening of remaining groundwater data, there is no evidence of any other groundwater plume or continuing source of contamination within WSIA groundwater. Both USEPA Region III and MDE agreed with this conclusion and indicated there is no need for a groundwater evaluation in the CERCLA human health risk assessment.

The following is a brief but comprehensive overview of historical use and an assessment of contamination for the potential source areas at each site within the WSIA. The sites are grouped within their respective cluster and AEDB-R number. Figures 4 and 5 depict the RI soil and surface water/sediment sampling locations associated with the WSIA.

AEDB-R No. EAOE12 Sites

H-Field Pre-WWII Artillery Target Area 1 (Figure 3 Site A): The Pre-WWII Artillery Target Area I is one of three of the H-Field Chemical Munitions hnpact Areas described in the RCRA Facility Assessment (RFA) and located in the vicinity of the H-Field test range support buildings. Grass-covered fields currently cover this site. During the 1920s and 1930s, the Target Area was used for open air and static testing of chemical agents (primarily mustard, phosgene, and other agents) including artillery barrages, bomb drops, ,- ... ~_:_L-___,,,.,,.....--=__;:;""'"'"':_,,------__y--::....~-=-=~Ii II SI'E KEY .3=. '1" '1" il A M-fICU) ...... MlU,Qlltwarr ...... c ....._­ r ­ ,; B ~~U-IIPftC'l:tlMC1l'II wI4 & I ~ , ~. I....L 'r't' " C H-NIlI ,...,~.. ~ INSEt, d o H4WLD -.....ex ~.,. SCOI.£::" -200" J • E ~~ ...... 1'WJ. P., F ..-_ Il ';....,J-J'.",..-~~~..'Ij! I! Ii 'I ! I

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and spray tank dispersion. Seventy-five millimeter artillery rounds were the most commonly fired munitions in documented tests. During some of these tests, hundreds of rounds were fired with as many as 25 percent ofthem failing to function. In many cases, rounds missed the target areas and were not destroyed or removed (USAEHA, 1989). RI field inspections of the site indicated little to no evidence of ordnance-related items lying on the ground surface, subsurface burial ofwastes, or ground scars.

Based on the site surface soil samples, the highest metal concentrations were antimony at 1.5 milligram per kilogram (mglkg) (Biological Technical Assistance Group [BTAG] value of 0.27 mg/kg), and cadmium at 0.49 mglkg (BTAG value of 0.36 mg/kg), and mercury at 0.1 mg/kg (BTAG value of 0.058 mg/kg) from C12-SS-01; and aluminum at 10,600 mg/kg (BTAG value of 1 mg/kg), and arsenic at 3.3 mglkg (RSL industrial value of 1.6 mglkg), and iron at 20,000 mg/kg (BTAG value of 12 mg/kg), and thallium at 0.18 (BTAG value of 0.001 mg/kg) from C12-SS-02. These metal concentrations in surface soil exceed BTAG values but are below the background values of 19,500 mglkg for aluminum, 5 mglkg for antimony, 7.6 mg/kg for arsenic, 1.4 mg/kg for cadmium, 21,700 mg/kg for iron, and 1.2 mglkg for mercury. [Note: Thallium does not have a background reference value.) One phthalate di-n-octyl phthalate (at 36 Ilg/kg) and one pesticide endosulfan sulfate (at 1.9 Ilglkg) were also detected in surface soil sample C12-SS-01. Both compounds have no RI screening criteria. The pesticide degradation product 4,4'-dichlorodiphenyldichloroethylene (ODE) was detected in surface soil exceeding the BTAG screening level of 0.021 Ilglkg. However, the maximum detected value of4,4'-DDE of3.3 Ilglkg was below the established background value of 392 Ilg/kg. No explosive-related compounds or chemical agent degradation compounds were detected. No chemical detections from past contaminant releases, UXQ, or training activities have been identified.

H-Field Building E1464 Septic Tank Site

The septic system received toilet, sink, and shower wastewater, but no floor-drain wastes from the shop area. Drain field malfunctions previously occurred with water seeping into the road ditch adjacent to the drain field. The water seepage was in small enough quantities that the runoff would not travel a great distance or reach the Gunpowder River. The 1,000-gallon septic tank is currently used as a holding tank for toilet and sink wastewater from Building E1464. The septic tank effluent line has been plugged; there is currently no discharge to the septic drain field. Seepage from the drain field to the adjacent road ditch has also ceased since the drain field is no longer used. The tank is pumped out every two months.

In addition to the septic tank, three petroleum USTs were located near Building E1464. The heating system for Building E1464 burns fuel oil which was stored in a 1,000 gallon UST adjacent to the north side of the east end of Building E1464. This fuel oil tank was installed in 1953. A diesel and gasoline refilling point was located 50 ft east of Building E1464 and had two associated USTs. The diesel and gasoline tanks had 680 and 768 Record ofDecision Final OEA Western Shore Investigation Area August 20ll Aberdeen Proving Ground, Maryland Page 20

gallon capacities respectively. These two adjacent tanks were installed in 1969. The three USTs have been removed and replaced with aboveground storage tanks.

Only the pesticides 4,4'-DDD and endrin ketone, and several metals at concentrations all below background and R,SL industrial values were detected in surface soil samples at the site. Subsurface soils were collected at 10 locations downgradient of the fonner petroleum USTs for VOC analysis only. Six VOCs, in particular BTEX constituents, were detected above BTAG and RSL for industrial soil values at subsurface soil samples taken nine feet below ground surface from locations WS-SO-031, WS-SO-032, and WS-SO-033. Subsurface soil location WS-SO-o31 contained the highest levels of VOCs, reporting benzene at 6,900 J.Lglkg (with a BTAG value of 100 J.Lglkg and RSL industrial value of 5,600 J.Lg/kg), bromomethane at 11,000 J.Lg/kg (with an RSL industrial value of 35,000 J.Lglkg), chloromethane at 4,600 J.Lglkg (with an RSL industrial value of 8,400 J.Lg/kg), ethylbenzene at 140,000 J.Lglkg (with a BTAG value of 100 J.Lglkg and RSL industrial value of 29,000 J.Lg/kg), toluene at 320,000 J.Lglkg (with a BTAG value of 100 J.Lg/kg and RSL industrial value of46,000,000 J.Lg/kg), and xylenes at 690,000 J.Lglkg (with a BTAG value of 100 J.Lglkg and RSL industrial value of 2,600,000 J.Lg/kg). The same six VOCs were detected in downgradient subsurface soil locations WS-SO-032 and WS-SO-033 but at lesser concentrations. Subsurface soils at the remaining seven locations downgradient of the fonner petroleum USTs did not contain VOCs.

H-Field Building El467 Storage Site

Based on site surface soil results, the PCB aroclor-1260 was detected at CI2-SS-08. The PCB detection (at 20 J.Lg/kg) was below all RI screening criteria. Numerous metals were detected above the BTAG screening values, but below the remaining screening criteria in two surface soil samples taken at the site. Seven metals, aluminum (at 7,510 mglkg), antimony (at 0.44 mglkg), arsenic (at 3 mglkg), iron (at 16,400 mglkg), thallium (at 0.17), and vanadium (at 23.6 mg.kg) were detected at surface soil sample CI2-SS-03, with only the arsenic detection above the RSL industrial soil value of 1.6 mg/kg. Aluminum, antimony, iron, lead, mercury, thallium, vanadium, and zinc were detected at surface soil sample CI2-SS-08 (at 14,100 mglkg, 0.39 mglkg, 21200 mglkg, 19.1 mglkg, 0.11 mglkg, 0.17 mglkg, 30.4 mglkg, and 70.5 mglkg, respectively). No VOCs, SVOC, pesticides, explosive-related compounds, or chemical agent degradation compounds were detected in surface soils at the site. No chemical detections from past contaminant releases, UXO, or training activities have been identified.

H-Field Washrack Wastewater Site

by 60-ft sedimentation pond. It is not known if two 250-gallon USTs were removed during this later upgrade. Before 1978, wastewater from the vehicle wash rack was most likely discharged directly to the drainage basin. Discharge from this facility is regulated by a National Pollutant Discharge Elimination System permit which requires monthly sampling of the wastewater discharge for oil and grease, total suspended solids, and pH. No permit exceedances have been identified during monitoring. Any permit exceedances and resulting corrective actions are handled under APG's compliance program.

A few VOCs, SVOCs, and metals, but no explosive-related compounds or chemical agent degradation products were detected in the two surface water and sediment sample locations taken within drainage ditches at the site. No VOCs, SVOCs, or pesticides were detected in surface water sample CI2-SW-05. However, the corresponding sediment sample at C12­ so-os contained the SVOC bis(2-ethylhexyl)phthalate at 28,000 J.1g1kg. This detection exceeded the BTAG screening value (180 J.1g1kg) and the established background value (9,300 J.1g/kg), but was below 10 times the RSL for industrial soil. Surface water sample CI2-SW-05 did contain levels oftotal iron during both rounds ofsampling (at 705 J.1g/L and 5,040 J.1g/L, respectively) above the BTAG screening value of 300 J.1g/L. Silver was detected only during round 2 of surface water sampling at CI2-SW-05 (at 4.8 J.1g/L) above the BTAG screening value of 3.2 J.1g/L. Sediment sample CI2-SD-05 contained only iron (23,200 mglkg) above the BTAG screening value of20,OOO mglkg. All other detected metal concentrations were below RI screening criteria at CI2-SW/SD-05.

The second surface water and sediment sample CI2-SW/SD-06 also contained a few detections of VOCs and SVOCs, all at concentrations below RI screening criteria Both rounds ofsurface water sampling at CI2-SW-06 contained elevated levels of total iron, total copper, and total zinc above one or more of the RI screening criteria. Round 2 had the highest reported concentrations of iron at 10,400 J.1g/L (BTAG value of 300 J.1g/L and background of 5,860 J.1g/L), ofcopper at 14.8 J.1g/L (BTAG value of9 J.1g/L and background of 12.5 J.1g/L), and of zinc at 535 J.1g/L (BTAG value of 120 J.1g/L and background of 78 J.1g/L). Sediment sample C12-SD-06 contained only zinc (at 247 mglkg) above the BTAG value of 121 mglkg.

H-Field Groundwater Supply Well (Figure 3 Site E): The H-Field Groundwater Supply Well obtains groundwater for non-potable use (Le., not for drinking water consumption or shower use). Two groundwater supply wells (SP-l and SP-2) originally existed. The older well (SP-l),located in the former Building EI460 pump house 30 feet south of Building E1464, was believed to be installed during the 1940s. The depth of well SP-l was measured at 75 feet below ground surface. The newer well SP-2 (98 feet deep, 48 gallons per minute), located approximately 50 feet southeast of the older well, was installed in 1983 after the older well started pumping sand. The SP-l was properly abandoned on June 5, 1998 in accordance with MOE regulations.

Groundwater samples collected in 1985 from one of these wells indicated the presence of 1,4-dithiane and chloroform. The RFA did not identify which well was sampled or the concentrations. RFA sampling of both wells in 1987 did not confirm the presence of 1,4­ dithiane and chloroform; however, SP-l contained low levels of toluene (at 5 J.1g/L), RecordofDecision Final OEA Western Shore Investigation Area August 2011 Aberdeen Proving Ground, Maryland Page 22

2,4,6-trinitrotoluene (at 9 ~gIL), and phthalates (at 21 ~gIL) (USAEHA, 1989). Two rounds of RI sampling of well SP-l in 1997 identified one VOC benzene (at 0.6 ~gIL, Round 2 only) slightly above the RSL tap value of0.41 ~gIL and below the MCL of 5 ~gIL. Inorganic compounds lead and zinc were also detected above background reference values but below their MCL and RSL tap values in SP-l at 3.5 J,Lg!L (Round 1 only) and 477 ~ (Round 2), respectively.

Debris Mounds (Figure 3 Site Fl: The Debris Mounds lie in the southern portion ofthe WSIA west of Ricketts Point Road. The Debris Mounds are over 10 feet above the original ground surface and contain predominantly natural materials (e.g., vegetation and blown down tree root mass) with soil or wastes associated with range clearing activities. Another feature is a series of low-profile dirt mounds running north-south and east-west on the western side of Ricketts Point Road, from the northern boundary of H-Field to the middle of the WSIA. The low-profile mounds are less than two feet above ground surface. Surface material was recovered from the low-profile dirt mounds during site characterization activities in 2008 and the larger dirt mounds were graded level with original ground surface.

Based on the surface soil data, metals and to a lesser extent pesticides were detected during characterization sampling of the Debris Mounds found throughout the WSIA. There were few detections ofVOCs, SVOCs, one chemical agent degradation compound, and explosive-related compounds; of which none exceeded the RI comparison criteria, where available. The mustard agent degradation compound thiodiglycol, which does not have RI comparison criteria, was detected in sample WS-SS-004 at 9.2 ~gIkg and in sample WS-SS-020 at 5.8 ~gIkg. The explosives 2,4-dinitrotoluene and tetryl, were detected in several samples within the Debris Mounds of I-Field. 2,4-Dinitrotoluene was detected below the RSL industrial value of 1,200,000 ~gIkg in only one sample WS-SS­ 030 at 320 ~gIkg. Detected concentrations of tetryl were found in four mound samples (WS-SO-025 at 53 ~gIkg, WS-SO-026 at 42 ~gIkg, WS-SO-027 at 49 ~gIkg, and WS­ SO-028 at 57 ~gIkg) well below the RSL industrial value of2,500,000 ~gIkg.

The pesticide 4,4'-DDT and its degradation products, 4,4'-DDD and 4,4'-DDE (DDTr) were detected in surface soil exceeding RI criteria, mainly the BTAG screening level. 4,4'-DDD was detected at a maximum concentration of 57 ~gIkg in sample WS-SS-044, exceeding both the BTAG screening value (0.021 ~gIkg) and the established background value (25.5 ~gIkg). For the remainder ofthe Debris Mound samples, 4,4'-DDE and 4,4'­ DDT exceeded the BTAG screening values of 0.21 ~gIkg but were below the established background values of 392 ~gIkg and 143 ~gIkg, respectively. It appears that the concentrations of DDTr may be the result of accumulation over time from the legal application ofpesticides, rather than site-related disposal or waste generation.

Metals were detected in surface soil samples at the WSIA Debris Mounds. Concentrations of metals exceeding at least two RI comparison criteria (typically the BTAG screening level and the reference background value) were detected at three locations (WS-SS-020, WS-SS-Q23, and WS-SS-024). Metals that exceeded both BTAG and the reference background criteria include; lead (150 and 202 mglkg) in WS-SS-020 Record ofDecision Final OEA Western Shore Investigation Area August 2011 Aberdeen Proving Ground, Mary/and Page 23 and WS-SS-023, respectively; and zinc (108 and 102 mglkg) in WS-SS-023 and WS-SS­ 024, respectively.

In June 2008, six composite soil samples (WS-MD-l to WS-MD-6) and five grab soil samples (WS-SO-l to WS-SO-5) were collected to characterize the low-profile Debris Mounds within the H-Field portion of the WSIA. Methylene chloride was the only VOC detected (with the highest detection of 11 J.l.glkg at WS-SO-2) but did not exceed either the RSL for industrial soil (54,000 J.l.glkg) or BTAG screening level (300 J.Lg/kg). Three SVOCs were detected. Bis(2-ethylhexyl) phthalate was detected in each composite soil sample but did not exceed any Rl comparison criteria, where available and diethyl phthalate was detected in WS-MD-6 at a concentration of 790 J.l.glkg; exceeding the background value (260 J.l.g/kg) but below the RSL for industrial soil (490,000,000 J.l.g/kg). The SVOC pyrene was detected in grab sample WS-SO-l at a concentration of 56 J.l.g/kg; exceeding the BTAG screening level of 1.1 J.l.glkg, but below the reference background value of 620 J.l.glkg. 4,4'-DDD, 4,4'-DDE, 4,4'-DDT, and dieldrin were detected in WS­ MD-l, WS-MD-3, WS-MD-6, WS-SO-l, and WS-SO-3 above the BTAG screening level of 0.021 J.l.glkg but below the RSL for industrial soil and reference background values, where available.

Metals were consistently detected in the composite and grab samples within the H-Field low-profile Debris Mounds. The composite and grab samples were taken at locations where metallic waste material was removed from the low-profile dirt mounds. Most metal concentrations were above the BTAG screening levels and included; aluminum, antimony, arsenic, chromium, iron, lead, manganese, mercury, selenium, vanadium, and zinc. Iron was detected at a maximum concentration of 23,200 mglkg in WS-MD-2, exceeding both the reference background of 21,700 mg/kg and BTAG screening level of 12 mglkg. Calcium slightly exceeded the reference background value of 2, 170 mglkg in WS-SO-2 only at 2,180 mglkg. Lead and zinc exceeded both the reference background (60.1 and 81.9, respectively) and the BTAG screening levels (11 and 46 mglkg, respectively) in WS-SO-l at concentrations of 81.4 mglkg and 152 mg/kg, respectively. All other metals were below the reference background.

6 CURRENT AND POTENTIAL FUTURE LAND AND RESOURCE USES

The Army currently uses the Edgewood Area for military/industrial land use activities. According to the APG Real Property Master Plan, current and planned future use of the WSIA is military/industrial.

APG lies adjacent to the Chesapeake Bay, approximately 20 miles northeast of Baltimore, Maryland, with most of the installation lying within Harford County. Major rail and road corridors run through southern Harford County. Major road corridors include U.S. Interstate 95, U.S. Route 40, Maryland Route 7, and Maryland Route 24. Extensive passenger and cargo rail traffic travels on the Amtrak and Conrail lines that run northeast to southwest along the APG installation boundary.

Land use surrounding APG is a mix of commercial and residential use, but also includes some agricultural use. Industry is most concentrated along Route 40. Primary population RecordofDecision Final OBA Western Shore Investigation Area August 2011 Aberdeen Proving Ground. Maryland Page 24 centers within eight miles of the Edgewood Area include the communities of JoppatownelMagnolia (population 11,391); Edgewood (population 23,378); and Bel Air (population 75,523). Smaller communities surrounding the Edgewood Area include Abingdon, Belcamp, Chase, and VanBibber. The 2009 population of Harford County was 242,514 (www.census.gov).

APG has substantial workforce and military-residential populations. The APG workforce nwnbers approximately 18,000 people and is projected to reach approximately 22,000 by 2012. Approximately 2,000 military dependents reside at APG. In the Edgewood Area, the workforce and residential areas are concentrated in the northern portion of the facility. As part of the "APG 2012 Transfonnation" Program, improvements will be made to infrastructure, facilities, and services at APG over the next few years. Several facilities, including the new u.s. Army Medical Research Institute of Chemical Defense Campus, are being constructed within the Edgewood Area as part of this program and in response to Base Realignment and Closure (BRAC) activities. Enhanced use leasing options are also being considered for parcels adjacent to the northern boundary of the Edgewood Area, by the Maryland Department of Transportation and Northeast Maryland Waste Disposal Authority. Currently, there are no plans for BRAC development within the WSIA.

Recreational activities on the Edgewood Area include hunting, trapping, shoreline fishing and crabbing, boating, sports and picnicing. Recreational sites are used by active and retired military personnel and families, as well as civilians. The water areas of the Gunpowder and Bush Rivers adjacent to the Gunpowder Neck are used extensively by recreational boaters. Nwnerous boat ramps and marinas provide access to the Gunpowder and Bush Rivers. The waters of APG support both commercial and recreational fishing. Boat'traffic within the installation boundaries is restricted by range control during firing exercises and enforced by APG patrol boats. There are no designated recreational areas within the WSIA. The Army has posted no trespassing signs on shorelines informing potential trespassers of UXO dangers. Access to the area is limited to properly cleared personnel or individuals in an escorted capacity. A wide variety of physical security countermeasures, including barrier systems, sensors and random patrols by law enforcement personnel, are in place to prevent unauthorized access.

7 SUMMARY OF SITE RISKS

7.1 Human Health

The purpose of the Human Health Risk Assessment (HHRA) is to determine whether exposure to site-related contaminants could adversely affect human health. The lllIRA estimates risks the site would pose under current or potential future use conditions if no remedial action were taken. The risk is expressed as the lifetime excess cancer risk (LECR) for carcinogens, and Hazard Index (Ill) for non-cancer adverse health effects.

The HHRA was performed for both current and anticipated future land-use scenarios (i.e., military/industrial) at the WSIA. Since APG is an active military installation, site workers (maintenance and commercial), construction (excavation) workers, and potential trespassers (adolescent) were evaluated as people who may reasonably be exposed to site Record ofDecision Final OEA Western Shore Investigation Area August 2011 Aberdeen Proving Ground, Mary/and Page2S

contaminants. Hypothetical future resident scenarios (adult and child) were evaluated for planning purposes only. Since RI data quality objectives were developed based on future military/industrial land usage, the number and spatial distribution of environmental samples while appropriate for that land use, are not sufficient to conclude that there are not unidentified hot spot areas that could pose a risk to hypothetical future residents.

Evaluated receptor exposure routes included ingestion and absorption through the skin of chemical contaminants present in area surface soil, sediment, and surface water, along with inhalation of chemical contaminants present in area surface soil. Using receptor exposure routes, exposure point concentrations, and chemical toxicity data, LECRs for carcinogenic chemicals and ill values for chemicals having non-carcinogenic effects were estimated. The acceptable range for the LECR is from lE-06 to lE-04. An LECR of lE-06 represents the probability that one person will contract cancer as a result of exposure to site related contaminants in a population of one million people exposed. An LECR of lE-04 represents the probability that one person in ten thousand exposed individuals will contract cancer as a result ofexposure to site-related contaminants.

A Hazard Quotient (HQ) is derived for each contaminant by comparing the anticipated level of exposure or dose to a receptor to the reference dose for that exposure scenario at which no adverse health effects occur. The HQs for all contaminants affecting a given exposure route or organ are summed to give the HI. The estimated non-cancer ill values are then compared to a value of 1.0 to detennine whether any non-cancer effects are anticipated from exposure to site contaminants. An ill value above 1.0 indicates a potential for adverse health effects.

Calculated cancer risks and non-cancer hazards from the Baseline Human Health Risk Assessment for the Western Shore Investigation Area (EA Engineering & Science [EA], 2008a) for exposure to site-wide surface soil, sediment, and surface water under current and future land use conditions are provided in Tables 1 and 2.

Under current and future land-use conditions, the cumulative LECR for adolescent trespassers based on exposures to surface soil, sediment, and surface water is 7.6E-07. The carcinogenic risk is 1.5E-07 for exposure to surface soil, 2.2E-07 for exposure to surface water, and 4.0E-07 for exposure to sediment. The cumulative non-cancer HI for the adolescent trespasser is 0.23. The total non-cancer ill for the adolescent trespasser is 0.019 for exposure to surface soil, 0.2 for exposure to surface water, and 0.013 for exposure to sediment.

For the maintenance worker, the cumulative LECR is 3.6E-07 under current and future land-use conditions based on exposures to surface soil and surface water. The carcinogenic risk is 2.6E-07 for exposure to surface soil, and 9.8E-08 for exposure to surface water. The cumulative non-cancer ill for the maintenance worker is 0.056. The total non-eancer HI is 0.0062 for exposure to surface soil, and 0.05 for exposure to Record ofDecision Final OEA Western Shore Investigation Area August 2011 Aberdeen Proving Ground, Maryland Page 26

Table 1. Summary of Risks Associated with Exposures in the WSIA Under Current and Future Land Use Conditions

, . ~'I~ ~JI:?' : on!Ciiiii ~em. 'lOj I. . Surface Soil: Incidental Inaestion 1.0£.07 Arsenic <1 1.8E-02 Iron Dermal Contact 4.1£.08 Arsenic <1 6.6E-04 Arsenic Inhalation 4.7E-I0 Chromium <1 1.6E-04 Man2lUlese Total I.SU7 <1 1.9E"()2 Surface Water: Incidental InKestion 1.9£.07 Arsenic <1 (6.9E-02) Iron Dermal Contact 2.S£.08 Arsenic <1 (1.3E-01) Vanadium Inhalation -- NA -- NA Total 2.2E"()7 <1 (2.0E"()I) Sediment: '. Incidental Inaestion 6.OE-08 Arsenic <1 (6.6E-03) Iron Dermal Contact 3.3£.07 Arsenic <1 (6.SE-03) Arsenic Inhalation - NA - NA Tolill 4.0E"()7 "L)'~- <1 n.3E"()2) Total RLskIHtIZIlrd Index Across AU Media andAU 7.6£-07 <1 (2.3E-Ol) Ex/Josure ROlltes '~.;~»*:;g!ue\'WiirUi'l ~ ti N~~ Pi'iilom~ ~ 1 ~ " J"LP.t6rtei"tlipvz • 1ltir e..aa K: eJielRteiIi Surface SOU: Incidentallngestion 1.9E-07 Arsenic <1 (S.7E-03) Iron Dermal Contact 7.SE-08 Arsenic <1 (4.7E-04) Arsenic Inhalation S.8E-I0 Arsenic - NA Total 2.6E-07 <1(6.2E"()3) Surface Water: Incidental Inaestion 7.3E-08 Arsenic <1 (8.6£.03) Iron Dermal Contact 2.4E-08 Arsenic <1 (4.1E-02) Vanadium Inhalation - NA -- NA Total 9.8E-OB <1 (S.OE"()2) Sediment: Incidental In2estion -- NA - NA Dermal Contact - NA -- NA Inhalation - NA .- NA Tolill - - Total RLsklHaZllrd Index Across AllMedia and AU 3.6£-07 <1 (5.6E-02) Exposllre ROlltes NA Not applicable RecordojDecision Final OEA Western Shore Investigation Area August 2011 Aberdeen Proving Ground, Maryland Page2?

Table 2. Summary of Risks Associated with Exposures in the WSIA Under Future Land Use Conditions

9.3&07 Arsenic Iron 3.7E-07 Arsenic Arsenic 9.SE-IO Arsenic NA Totlll 1.3E-06 TOMI RiskIHiWlrd Index Across AU Media andAU 1.3&06 <1 (3.0E-02) sure Routes aM'orlW' ~ . Surface Soil: Incidental In cstion 3.6E-07 Arsenic Iron Dcnnal Contact 2.2&08 Arsenic Arsenic Inhalation 2.2E-IO Arsenic NA TolJll 3.8E-07 ToW RiskIHazard Index Across AU Medill and AU 3.8&07 <1 (2.7E-01) sure Routes NA Not applicable RecordofDecision Final OEA Western Shore Investigation Area August 2011 Aberdeen Proving Ground, Maryland Page 28

Table 2. Summary of Risks Associated with Exposures in the WSIA Under Future Land Use Conditions (continued)

"~~I~ Jf .~~li~ ~I~ jP.iiClOiii'ii@~ IlIIl'f\i~ ~ ­ .rlBi .. ,-f.. i&JIl" .. c:erdl. I~ ..\..1l_~_ ~ Surface Soil Child): Incidentallnsr:estion 6.2E-06 Arsenic 1.4 Iron Dcnnal Contact S.9E-07 Arsenic :~~;; <1 fl.6E-01 Surface SoillAdult + Child): ..., :"', Incidental Insr:estion S.9E-Q6 Arsenic :ri '11 ~ Dcrmal Contact 9.5E-07 Arsenic Inhalation 7.1E-oS Chromium. Total Totalfor AdIIJt + Ch/ld 1J.9E-06 .Total1lllkACIW1U S""(I(¥ &II 9.9&46 Surface Water (Child): Incidentallngcstion 1.7E-Q7 Arsenic <1 (S.3E-02) Iron Dermal Contact I.IE-07 Arsenic

Totalfor Adult + Child 6..9E-lJ7 • 'Cd}'}. ~ TotfllllldAeron SMrf(l(¥ W.. 6.9B-fJ7 Sediment (Child): Incidentallnltcstion 2.7E-07 Arsenic <1 (4.0E-02) Iron DcrmaI Contact 6.8E-OS Arsenic

Under future land-use conditions, the cumulative LECR for commercial workers based on exposure to surface soil is 1.3E-06. The cumulative non-cancer HI for the commercial worker is 0.03. The cumulative LECR and HI for the construction worker (based on exposure to surface soil) under future-land use conditions are 3.8E-07 and 0.27, respectively.

Based on the limited sampling conducted at a spacing designed for industrial land use, calculations were also performed to assess the cancer risk and non-cancer hazard presented for hypothetical future residents. For the hypothetical future resident (adult and child combined), the cumulative LECR from exposure to surface soil, surface water, and sediment is l.lE-05. The hypothetical future resident exposure to surface soil, surface water, and sediment carcinogenic risks are 9.9E-06, 6.9E-07, and 4.8E-07, respectively. The cumulative non-cancer HI for the hypothetical future resident child is 2.4. The total non-cancer HI for exposure to surface soil is 1.4 (primarily due to exposure to iron), for exposure to surface water is 0.88 and for exposure to sediment is 0.042. However, no target organ-specific HI exceeds 1.0. Therefore, there do not appear to be any non-cancer risk concerns for the hypothetical future resident child. The cumulative non-cancer HI for the hypothetical future resident adult is 0.65. The total non-cancer HI is 0.16 for exposure to surface soil, 0.48 for exposure to surface water, and 0.0044 for exposure to sediment.

For the WSIA, the calculated risks for all receptors (i.e., current/future adolescent trespasser, current/future maintenance worker, future construction worker, future commercial worker, and future resident adult and child) are within, or below, the established risk thresholds for carcinogens (lE-06 to 1E-04) and did not exceed the non­ cancer HI threshold of 1.0 with respect to any target organ. There are no carcinogenic or non-earcinogenic risk concerns for any of the receptors. Blood-level lead modeling was not conducted at the WSIA since models used are for exposure to lead in soil and groundwater, and lead was not detected in either media above the USEPA screening criteria There were elevated concentrations of lead in marsh surface water when compared to the lead drinking water action level. However, an evaluation of lead in surface water indicates that lead is not a site-wide concern. Detected locations were not in close proximity to each other and were not downgradient of high soil lead concentrations. Furthermore, corresponding sediment samples did not exceed screening criteria for lead (EA, 2008a).

After the HHRA was finalized in early 2008, additional site characterization of potentially contaminated material was conducted at the WSIA. Sampling included the collection of eight surface soil samples to assess the potential for contamination from surface debris associated with the low-profile Debris Mounds (Figure 3, Site F) located in the northern portion of the investigation area A risk-based screening was conducted by comparing the maximum detected chemical concentrations in the surface soils to USEPA residential and industrial soil RSLs. In accordance with USEPA guidance, RSL values used were those at a carcinogenic risk level of 1E-06 and a HQ of 0.1. Maximum detections of RecordofDecision Final OEA Western Shore Investigation Area August 2011 Aberdeen Proving Ground. Mary/and Page 30

alwninwn, arsenic, cadmiwn, cobalt, iron, manganese, thallium, and heptachlor epoxide exceeded the screening values and were identified as COPCs for residential exposures to surface soil. Only arsenic was identified as a COPC for industrial exposures to soil. Risk estimates were then calculated. For the residential child receptor, the cumulative ill was 1.9. Although this value is slightly above the target value, no individual target organs exceeded acceptable level of 1.0. For the industrial receptors, there were no non-cancer COPCs. Cumulative carcinogenic risks were within the USEPA's established risk thresholds at IE-OS for the residential scenario and at 3E-06 for the industrial scenario. Based on these results, the conclusions of the lllIRA for the WSIA remain unchanged and no further risk evaluation is warranted based on projected future land use (military/industrial) (EA, 2008c).

7.2 Environment

The Screening-Level Ecological Risk Assessment and Baseline Risk Assessment Problem Formulation for the Western Shore Investigation Area (EA, 2008b) evaluated all soil, sediment, and surface water samples in the WSIA as one data grouping in the ecological risk assessment. The following potential receptors and exposure routes were identified for WSIA surface soil, sediment and surface water:

~ Terrestrial Plants - direct contact (root uptake)

~ Terrestrial Invertebrates (earthworms) - dermal contact and ingestion

~ Small Herbivorous Mammals (meadow vole) - ingestion

~ Invertebrate-Eating Birds (American robin) - ingestion

~ Invertebrate-Eating Mammal (short-tailed shrew) - ingestion

~ Higher Trophic Level Predatory Birds (red-tailed hawk) - ingestion

~ Higher Trophic Level Predatory Mammals (red fox) - ingestion

~ Benthic and Aquatic Organisms (multiple species) - direct contact with, respiration of, and ingestion of sediment and surface water

~ Aquatic Organism-Eating Birds (great blue heron) - ingestion

~ Aquatic Organism-Eating Mammals (mink) - ingestion

COPCs were selected based on a screening comparison of on-site concentrations to Region III Ecological Soil Screening Levels and BTAG values. Exposure concentrations for the COPCs were then compared to Toxicity Reference Values (TRVs).

No significant risk to ecological receptors was identified for the WSIA. The Baseline Risk Assessment Problem Formulation, Step 3, concluded that on-site concentrations of chemicals, although greater than BTAG values, are unlikely to affect the assessment RecordofDecision Final OEA Western Shore Investigation Area August 20ll Aberdeen Proving Ground, Maryland Page 3] endpoints identified in Steps 1 and 2 ofthe Screening-Level Ecological Risk Assessment, and that site-wide populations of the receptors of concern at the WSIA are unlikely to be at risk from on-site chemical exposures. No COPCs were retained for further investigation.

Therefore. Steps 1-3 of the ecological risk assessment process provided enough information to warrant no further assessment of potential ecological risks. at the WSIA and to determine that completion of Steps 4-7 was not necessary.

8 REMEDIAL ACTION OBJECTIVES RAOs are goals developed for the protection of human health and the environment. These objectives can be achieved by reducing exposure (e.g.• capping an area or limiting access) as well as by reducing the concentration level of contaminants.

The RAO for the WSIA is to prevent unacceptable risk to future residential receptors through exposure to site-related contaminants.

9 DESCRIPTION OF ALTERNATIVES A summary description of remedial alternatives evaluated during the FFS is presented below. For the WSIA. only one remedial alternative (Alternative 2 - LUCs) was developed and retained for further evaluation and comparison with the No Action alternative (Alternative 1). given the limited hypothetical risk posed by the WSIA. the anticipated future use of the sites. and the ability of the Army to control access to the WSIA. For purposes of cost comparison. project duration of 30 years is assumed for both alternatives. However. LUCs are expected to be maintained in perpetuity or until contaminant levels are reduced to levels that allow for unlimited use and unrestricted exposure. or unless and until further sampling conducted at a spacing designed to assess risks associated with residential land use indicates that ·there are no unacceptable human health risks associated with unlimited use and unrestricted exposure to the site. 9.1 Alternative 1: No Action

The NCP requires consideration of ''No Action" as a baseline with which to compare other alternatives (40 Code of Federal Regulations 300.430(e)(6». Under this alternative. no active remedial measures would be taken to control risks to hypothetical future residents; treat or remove wastes; or reduce the toxicity. mobility. or volume of contaminated media. LUes would not be implemented and existing restrictions may not continue.

Estimated Capital Cost: $0 CERCLA Five-Year Review: $0 Estimated Total Present Worth Cost: $0 Estimated O&M Timeframe: None Estimated Time to Achieve RAOs: Will not achieve RecordofDecision Final OEA Western Shore Investigation Area August 2011 Aberdeen Proving Ground, Maryland . Page32

9.2 Alternative 2: LUCs

lIDs alternative involves implementation of LUCs that would be used to limit exposure to those areas where contaminant levels would not allow for unrestricted use. Modifications would be made to the Installation Master Plan and GIS Overlay Maps in order to prevent housing. elementary and secondary schools. child care facilities. playgrounds. and other residential land uses within the entire WSIA.

Because the potential presence of UXO will still exist at the WSIA. existing Installation safety procedures and policies related to uxa would be followed for any soil disturbances at the WSIA in the future. lIDs is to ensure adequate protection of workers and military personnel at the WSIA. CERCLA 121 (c) Five-Year Reviews would also be performed to evaluate the long-term effectiveness of the remedy. LUCs. as described above, will be implemented at the WSIA unless and until further sampling conducted at a spacing designed to assess risks associated with residential land use indicates that there are no unacceptable risks to human health associated with unlimited use of and unrestricted exposure to the site.

Estimated Capital Cost: $11,500 Estimated O&M Cost: $3,050 CERCLA Five-Year Review: $15,000 Estimated Total Present Worth Cost: $193,000 Estimated O&MlLTM Timeframe: 30 Years Estimated Time to Achieve RAOs: 6 Months

10 SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES

The following is a comparative analysis of the remedial alternatives considered for the WSIA. The potential performance of each alternative was evaluated in terms of the nine evaluation criteria required by the NCP. The nine criteria are categorized into one of three groups: threshold criteria, primary balancing criteria, and modifying criteria (Table 3).

10.1 OveraD Protection of Human Health and the Environment

The "LUCs" (Alternative 2) does. and "No Action" (Alternative 1) does not, prevent future residential exposure to contaminants present at the site. The ecological risk assessment identified no unacceptable current or future ecological risks. Since Alternative I does not meet this threshold criterion it is not considered further in this evaluation. 10.2 Compliance with Applicable or Relevant and Appropriate Requirements

No chemical-. location-, or action-specific ARARs are associated with the implementation of Alternative 2. Record ofDecision Final OEA Western Shore Investigation Area August 2011 Aberdeen Proving Ground, Maryland Page 33

Table 3. Remedial Alternative Evaluation Criteria

Threshold Criteria:

• Overall Protection ofHuman Health and the Environment refers to whether a remedy provides adequate protection against hannful effects. It calls for consideration of how risks to human health or the environment are eliminated, reduced, or controlled through treatment, engineering controls, or institutional controls.

• Compliance with Applicable or Relevant and Appropriate Requirements addresses whether a remedy meets all the applicable or relevant and appropriate requirements of federal and state environmental statutes.

Primary Balancing Criteria:

• Long-Term Effectiveness and Permanence refers to the magnitude of residual risk and the ability of a remedy to maintain reliable protection of human health and the environment after cleanup goals have been met.

• Reduction of Toxicity, Mobility, or Volume through Treatment refers to the effectiveness of the treatment technologies in reducing the toxicity, mobility, or volume of contaminants.

• Short-Term Effectiveness refers to the speed with which the remedy achieves protection and to the remedy's potential during con$truction and implementation to have adverse effects on human health and the environment.

• Implementability refers to the technical and administrative feasibility of a remedy, including the availability ofrequired materials and services.

• Cost includes capital expenditures and operation and maintenance costs.

Modifying Criteria:

• State Acceptance indicates whether the state concurs with, opposes, or has no comment on the preferred alternative based on its review of the RIJFS Reports, Proposed Plan, and public comments.

• Community Acceptance is documented in the ROD following consideration of public comments on the Proposed Plan. Record ofDecision Final OEA Western Shore Investigation Area August 2011 Aberdeen Proving Ground, Mary/and Page 34

10.3 Long-Term Effectiveness and Permanence

Alternative 2 would provide adequate long-term effectiveness in protecting human health by preventing uses that would result in possible harmful exposures to site-related contaminants. However, LUCs require ongoing maintenance and enforcement to remain effective.

10.4 Reduction of Toxicity, Mobility, or Volume through Treatment

Alternative 2 does not provide for reduction of toxicity, mobility or volume through treatment because no wastes or contaminated media were identified that required treatment

10.5 Short-Term Effectiveness

Alternative 2 does not involve construction activities that endanger public communities or remedial workers, or adversely impact the environment. The RAO would be achieved quickly upon implementation of LUCs (within 6 months).

10.6 Implementability

Alternative 2 does not depend on difficult-to-obtain equipment, services or technical specialists. LUes can be easily inserted into the Installation Master Plan and GIS Overlay Maps and administered by the Army, to include periodic inspections, reporting requirements, and enforcement. Therefore, Alternative 2 is technically and administratively feasible, and readily implementable.

10.7 Cost

The estimated cost for Alternative 2 is $193,000.

10.8 State Acceptance

State representatives have reviewed the alternatives in the Proposed Plan for remedial action at the WSIA. Based on a thorough review of the remedial response alternatives and public comments, MDE concurs with Alternative 2.

10.9 Community Acceptance

A summary transcript of the Public Meeting, held on June 14, 2011, is available in the Administrative Record. Responses to written comments received from the community are presented in Part 3 ofthis document.

11 PRINCIPAL THREAT WASTES

Principal threat wastes are those source materials considered to be highly toxic or highly mobile that generally cannot be reliably contained, or would present a significant risk to human health or the environment should exposure occur. Materials remaining at the WSIA would not constitute a principal threat waste. Record ofDecision Final OEA Western Shore Investigation Area August 2011 Aberdeen Proving Ground, Mary/and Page 35

12 SELECTED REMEDY

12.1 Description of the Selected Remedy

The Selected Remedy for the WSIA is Alternative 2: LUCs. The Selected Remedy may result in hazardous s,ubstances remaining on the site at levels that do not allow for unlimited use of and unrestricted exposure to the site; therefore, Five-Year Reviews will be required to be performed to verify that the remedy remains protective of human health and the environment. The detailed approach and methodology for implementing LUCs will be specified in the LUC RD.

~ Land-Use Controls: LUCs will be implemented at the WSIA to prevent site activities that would result in unacceptable exposure. The LUC will prevent housing, elementary and secondary schools, child care facilities, playgrounds, and other residential land use within the entire WSIA. The extent of the WSIA within which residential land use will be restricted is identified in Figure 6.

~ Five-Year Reviews: CERCLA 121(c) five-year reviews will be conducted to ensure the selected remedy remains protective. Five-year reviews will be conducted in accordance with OSWER Directives 9355.7-03B-P and 9234.2-25, or their most current revision or replacement. '

~ The RD will be submitted consistent with the RD schedule provisions of the FFA and will include the details of LUC implementation and maintenance (including periodic inspections). 12.2 LUC Remedial Design

The LUC RD will describe the details of LUC implementation and maintenance, including periodic inspections. The LUCs will be implemented through the APG Master Planning system with GIS support.

The Army will be responsible for implementation, maintenance, periodic inspection, reporting on, and enforcement of LUCs in accordance with the RD and this ROD. Although the Army may transfer these responsibilities to another party by contract, property transfer agreement, or through other means, the Army will remain responsible for:

~ conducting CERCLA Section 121(c) five year reviews;

~ notifying USEPA and MDE and/or local government representatives of any known LUC deficiencies or violations;

~ obtaining access to the property to conduct periodic inspections and any necessary response; and

~ ensuring that the LUC objectives are met to protect the integrity of the selected remedy. RecordofDecision Final OEA Western Shore Investigation Area August 20ll Aberdeen Proving Ground, Maryland Page 36

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The Army will not modify or tenninate LUCs or implementing actions without prior agreement of USEPA, after conferring with MOE. The Army will seek prior concurrence with USEPA and MDE before taking an action that would disrupt the effectiveness of the LUCs.

Ifthe Army transfers property in the areas addressed by this ROD, the Army will ensure that the restrictions on site activities are included in the deed to the property recorded in the local property records and that notification of the restrictions in the deed is filed with the appropriate agencies, so that current and future property owners will be aware of these restrictions. At the earliest possible time, but no later than 60 days prior to leasing or transferring Army-owned property under this LUC to another agency, person, or entity (including federal to federal transfers) the Army will provide notice to USEPA and MDE of such intended lease or transfer. Specific deed restriction language and the appropriate agencies will be identified in the approved RD. While the Army retains ultimate responsibility for LUC enforcement, the Army may require the transferee or lessee in cooperation with other stakeholders to assume responsibility for LUC implementation actions. Third-party LUC responsibility will be incorporated into pertinent contractual, property and remedial documentation, such as a purchase agreement, deed, lease and RD addendum. To the extent permitted by law, a transfer deed shall require the LUCs imposed as part of a CERCLA remedy to run with the land and bind all property owners and users. If the Army intends to transfer ownership of any site, the Army may, if federal and/or state law allows, upon transfer of fee title grant the state an environmental covenant or easement that would allow the state to enforce LUC terms and conditions against the transferee(s), as well as subsequent property owner(s) or user(s) or their contractors, tenants, lessees or other parties. This covenant will be incorporated by reference in the transfer deed and will run with the land in accordance with state realty law. This state enforcement right would supplement, not replace, the Army's right and responsibility to enforce the LUCs.

12.3 Summary of the Rationale for the Selected Remedy

Although the HHRA did not indicate the presence of any cancer risks or non-cancer hazards to human health for the hypothetical future adult and child resident exposure scenarios, this analysis was based on limited sampling conducted at a spacing designed for industrial land use. In order to verify that residential use ofthe site would not present an unacceptable human health risk, further sampling would need to be performed. The Selected Remedy for the WSIA is protective ofhuman health by preventing the use ofthe site for housing, elementary and secondary schools, child care facilities, playgrounds, and other residential usage. No unacceptable risks were identified for human health from COCs under an industrial land-use scenario. In addition, chemicals in surface media do not appear to pose unacceptable risk to ecological receptors (EA, 2008b). Because the potential presence of UXO will still exist at the WSIA, existing Installation safety procedures and policies related to UXO would be followed for any soil disturbances at the WSIA. This is to ensure adequate protection of workers and military personnel at the WSIA. RecordofDecision Final OEA Western Shore Investigation Area August 2011 Aberdeen Proving Ground, Maryland Page 40

This remedy is dependent on consistent implementation of LUCs to provide long-term effectiveness and permanence. It will not result in reduction of toxicity, mobility, or volume through treatment. The remedy will be implemented quickly and easily, and be effective in the short-term.

12.4 Summary of Estimated Remedy Costs

The information in the cost estimate summary is based on the best available information regarding the anticipated scope of the remedial response. TIlls is an engineering cost estimate that is expected to be within -30 to +50 percent of the actual project cost (USEPA, 1999; USEPA, 2000). The estimated cost for LUCs at the WSIA includes total capital cost, annual O&M costs and present worth over a 30-year period. However, LUCs are expected to be maintained in perpetuity or until contaminant levels are reduced to levels that allow for unlimited use and unrestricted exposure, or unless and until further sampling conducted at a spacing designed to assess risks associated with residential land use indicates that there are no unacceptable human health risks associated with unlimited use and unrestricted exposure to the site. The detailed costs are provided in Table 4, and summarized below: Cost Summary Capital Cost $11,500 Annual O&M Costs $3,050 CERCLA Five-Year Review $15,000 Total Present Worth Costs $193,000 O&M Time Frame 30 Years Time to Achieve RAOs 6 Months

12.5 Expected Outcomes of Selected Remedy

LUCs to prevent housing, elementary and secondary schools, child care facilities, playgrounds, and other residential land use will effectively control potential risk of unacceptable exposures upon implementation.

12.6 Performance Standards for the Selected Remedy

The following remedial performance standard was established for the WSIA remedy:

~ There shall be no development or use of WSIA property for housing, elementary and secondary schools, child care facilities, playgrounds, and other residential land use (See Figure 6).

13 STATUTORY DETERMINATIONS

13.1 Protection of Human Health and the Environment

Potential exists for risk to human health if no remedial action is undertaken. This remedial response meets the requirements of CERCLA Section 121 and, to the extent practicable, the NCP. The Selected Remedy (LUCs) for the WSIA protects human health Record ofDecision Final OEA Western Shore Investigation Area August 2011 Aberdeen Proving Ground. Maryland Page 41

Table 4. Detailed Costs for the Selected Remedy

ITEM UNITS I NUMBER I UNITCOST I TOTAL CAPITAL COSTS Work Plans· not required I I I I Access and Land Use Restrictions Notice Restrictions LumDSum I 1 I 10,000.00 I 10000.00 I I I SUBTOTAL $10,000.00 SUPERVISION ANO ADMIN flIl5% S5OO.00 CONTINGENCY /fD10% $1,000.00 TOTAL CAPITAL COST $11.500.00 ANNUAL O&M COSTS Administrative Actions >Year RevieW' ReDort I 1 I $3,000.00 I $3000.00 Institutional ControlslOvensight LumDSum I 0.2 I $5,000.00 I $1.000.00 Lona-Tenn MonltortnglMainienance Site (nsDedions LumDSum I 1 I $1500.00 I $1500.00 SUBTOTAL 55,500.00 CONTINGENCY /fD 10% $550.00 TOTAL O&M COSTS $6,050.00 PRESENT WORTH (30 YEARS) $193,000.00

Costs do not assume permit requirements. Costs incurred once every 5 yeans. therefore. the report cost was reported as 1/5 total costs on an annual basis. Record ojDecision Final OEA Western Shore Investigation Area August 2011 Aberdeen Proving Ground, Maryland Page 42

by preventing unacceptable exposure to site contaminants through prohibiting future residential usages: Chemicals in surface media do not appear to pose unacceptable risk to ecological receptors (EA, 2oo8b).

The RAO will be achieved upon implementation of the Selected Remedy, which will not cause any harmful short-term risks.

13.2 Compliance with Applicable or Relevant and Appropriate Requirements

There are no ARARs associated with LUCs.

13.3 Cost-Effectiveness

The Selected Remedy (LUCs) for the WSIA is considered to be cost effective. LUCs preventing future residential land usage will be implemented without perfonning extensive and expensive sampling, analysis and risk assessment work to precisely define risk to hypothetical future residents

13.4 Utilization of Permanent Solutions and Alternative Treatment Technologies to the Maximum Extent Practicable

The Selected Remedy is not necessarily a permanent solution since it requires ongoing O&M in the form of inspections. The remedy is however appropriate given the current and future land use scenarios (military/industrial) at APG. No treatment technologies are included in the remedy for the WSIA, given the limited hypothetical risk posed by the WSIA, the anticipated future use ofthe sites, and the ability ofthe Army to control access to the WSIA.

13.5 Preference for Treatment as a Principal Element

The Selected Remedy does not employ treatment to reduce toxicity, mobility or volume of hazardous substances, pollutants or contaminants and, therefore, does not satisfy the statutory preference for remedies that employ treatment as a principal element. The LUC remedy eliminates the principal risks at the WSIA through prohibition of future residential land use that would result in unacceptable exposure.

13.6 CERCLA 121(c) Five-Year Review Requirement

Hazardous substances, pollutants, or contaminants may remain on site at levels that do not allow for unlimited use and unrestricted exposure. Therefore, five-year reviews will be performed for the WSIA as required by CERCLA and the NCP. Five-year reviews will be conducted in accordance with OSWER Directiyes 9355.7-03B-P and 9234.2-25, or their most current revision or replacement.

14 DOCUMENTATION OF SIGNIFICANT CHANGES

No significant changes were made to the Proposed Remedial Action Plan since it was provided to the public for review and comment. Record ofDecision Final OEA Western Shore Investigation Area August 2011 Aberdeen Proving Ground, Maryland Page 43

PART 3: RESPONSIVENESS SUMMARY

The purpose of the Responsiveness Summary is to provide a summary of the public's comments, concerns and questions about the Proposed Plan for the WSIA, and the Anny's responses to these concerns.

APG held a public meeting on June 14,2011 to formally present the Proposed Plan and response actions and to answer questions and receive comments. The summary transcript of this meeting is part of the Administrative Record for the Edgewood Area. During the public comment period, APG also received written comments. All comments and concerns summarized below have been considered by the Anny and USEPA in selecting the response actions for the WSIA.

1 OVERVIEW

At the time of the public comment period, the Anny and USEPA had endorsed the Selected Remedy (LUCs) for the WSIA to protect human health and the environment.

Based on a thorough review of the remedial response alternatives and public comments, MDE concurs with the Selected Remedy.

2 BACKGROUND ON COMMUNITY INVOLVEMENT

APG has maintained an active public involvement and information program for the IRP since the early 1990s. APG's specific community relations activities for the WSIA were as follow:

• APG began discussing alternatives for the WSIA with the RAB in June 2009.

• APG released the WSIA Proposed Plan for public comment on June 8, 2011. Copies were available to the public through APG's administrative record locations at the Edgewood and Aberdeen branches of Harford County Library and Miller Library at Washington College in Kent County.

• A 30-day public comment period on the Proposed Plan ran from June 8 to July 7, 2011.

• APG prepared a release announcing the availability of the Proposed Plan, the dates of the public comment period, and the date and time of the public meeting. APG placed newspaper advertisements announcing the public comment period and meeting in The Aegis, The Avenue News, The Cecil Whig, East County Times and Kent County News. A sample newspaper advertisement announcing the public comment period and the public meeting is provided on Figure 7. RecordofDecision Final OEA Western Shore Irrvestigation Area August 2011 Aberdeen Proving Ground. Maryland Page 44

Figure 7 - Sample Newspaper Advertisement

US. ARMY INVITES PUBLIC COMMENT ON PROPOSED PLANS FOR THE I OTHER EDGEWOOD AREAS STUDY AREA WESTERN SHORE & DOVES COVE INVESTIGATION AREAS

n. us. Anfy at AH""IIProvIlIg G1'DlIIId (APG) 1""lIes 1M Jlf'bJic 10 COIII1II"" 011 its PropoudPlansfor IItt Ifbtem ~/...utlggl/OII AI'IQ (WSJA) tIIId /)(we, e.- /1WUtigatlOll A.frO (DCLf) III IItt Other EtJsn-oodAreas (OEA) ~ A.ND. FACfSHEET WRITTEN COMMENTS APG bas prepII'CIl! a fiIl:t I!aect CIII the propoted The 3o-day public COIIlU1mt period aD plus which itlc1lIdet a commCll1 form 1baI can the proposed COlI axtcDds er- JUIlC 8 to be RtutDed to APG. July 7, 2011. Writtm CICllIlDlaD, post. uwIPhiladelphia, PA 19103·2029; or 2122 EmmortCIII Pait Rc.d ML Pee Nemolr Edaewood. MD 21040 Mary1aDd DepanmCll1 ofthe EnvitoDmClll The meeting IocaIiOll is wheelcIIair acceasible. Fedcnl Facilities DiviliOD aDd au inIetpreIcr for the heariDg impaiRd is Hazardoua WUUl ProllJ1IIII aYIiIable with n·houn ad_aOOce (call 1800 WuhingtCIII BouIenrd, Suite 645 8OO·APQ·9998). BalIimIlrC, MD 21230-1719 PROPOSEDACI10N APG bas prepared Proposed Plam to address the WClA and DClA located in the OEA Study AmI in the Edgewood Atea ofAPO. ALTERNATIVES EVALUATED FOR EACH INVESTIGATION AREA Altenaative 1: No Acdoll. The Natioual Oil and Hazudous Substlmces Pollution ContiDgalcy PlaD (NCP) requires collSideralion of"NoAction" u a baseliDc with wbich to compare other aItcmalives. Under thiI alternative, no active remedial measures would be ta.lcen to conlrol risks to hypothetical future raidculS; treat or remove wastes; or reduce the toxicity. mobility, or volwne ofcoatamiDated modia. L&Dd Use controls (LUCS) would not be implc:mellled and existing IeSlrictions would not continue. Cost: SO A1tenlatlve 1: LUCa. The LUC a1temative would be used to limit expolUf'C to those ueas whese coataminant kvds wouId not allow for uareslrietcd usc. These COnlrolJ illClude IepI mecbaoisms and IlOIices to pmrmt teaidmtialland uses. Because the poteIt­ tiaI pmence ofUXO will still exist, existing Ins1lI1lalion SIlfety proccdwa and policies ~laIod to UXO will be followed for any soil distwbances in the futw-e. This is to ensure adequate prolCGlion ofworken and military personnel at the sites. ModifieatiollS would be made to the InslaIlatioo Master Plan and Oeographicallnformation Syst=s (GIS) Overlay Maps in order to prohibit housing, elrmeutary and secondary schools, child C8rC filciJilies. playgrollllds, and other residential-type land uses. LUCs would be mainlUned until COllCC:lltratioos ofbazardous I1IbstaDces in the soil, sutfal:e water. and sediment are at levels that allow for UD1imited use and umestric:ted exposure. Fivl>Year Reviews would also be performed III cvaluale the long-term etroctiveness ofthe remedy. Coat: 5193,_ for each IIIvestlptioa AJ:eIl Bued OD allDlyala 01 the altenaativ..APG prefen A1eenatlve 1, LUCa for the WSIAudDCIA The prefc:rrcd a1tetDative may be modiAed or DeW alternatives may be developed based on public input 'The final alternatives selected will be documented in a Record of Decision (ROD) for each IuvatiptionAmi that IIIIIIllWizea the decision-maIdng process. APG wiII slllDllWizc and tapond to COmmetltl -.ived during the comment period u put ofthe RODs. Copies ofthe Focused Feasibility Study and the Proposed Plan for the WSIA and DClA are available for IWiew ulhe APO infonnalion repositories. 'The repositories are located at the Edgewood (410·612-1600) andAberdcen (410-273-S608) brulches ofthe Harford CowUy Library and Miller Library at Wungton College in Kent CoIIIItV (41

• On June 14,2011, APG held a public meeting at the Hampton Inn in Edgewood, Maryland. Rq>resentatives of the Anny and USEPA were present at the meeting. APG representatives presented information on the WSIA and on the proposed response action.

3 SUMMARY OF COMMENTS RECEIVED DURING THE PUBLIC COMMENT PERIOD AND AGENCY RESPONSES

Comments raised during the public comment period are summarized below. The comments are categorized by source.

COMMENTS FROM QUESTIONNAIRE INCLUDED WITH FACT SHEET

As part of its fact sheet on th~ Proposed Plan, APG included a questionnaire that residents could return with their comments. APG received 11 forms; only 8 forms had a comment. The alternatives preferred by individuals returning comment forms were:

....L Alternative 1- No Action -.2..- Alternative 2 - LUCs

Written comments included on the forms are summarized below.

Comment No.1: (Commenter selected Alternative 1) There should be no residential development on any of the test sites at APG. The state government is always spouting about open areas. Leave this land as is and we would have open space. ----Maybe not quite the kind they would like but no houses, etc. could be built. There would be space for wildlife (controlled, I hope).--- The government has no "money" for other projects that could help the people better, so put this offuntil the economy is better ifever.

Response No.1: Although Alternative 1 (No Action) is the less costly alternative, the alternative selected for the WSIA must satisfy the threshold criterion, Overall Protectiveness of Human Health and the Environment, which is of primary importance. The preferred alternative (LUCs) for the WSIA is protective of human health through preventing future residential usages. Alternative 1 would not provide long-term protection to future residential from potential unacceptable exposure to site contaminants.

Comment No.2: (Commenter selected Alternative 1) I would like to have a few meetings at our community building. Edgewood is too far for many who live and work in the Chase area. I would also like information on the hazardous materials that the government is aware ofin the Oliver Beach area.

Response No.2: APG appreciates the feedback, and your suggestion to hold a few public meetings within the Chase area will be considered. A source of information about APG IRP sites near the Oliver Beach area is contained within the APG Administrative Record for the Graces Quarters Study Area The APG Administrative Record is available to the public at the Edgewood and Aberdeen Branches of Harford County Library and Miller Library at Washington College in Kent County. RecordofDecision Final DBA Western Shore Investigation Area August 2011 Aberdeen Proving Ground, Maryland Page 46

Comment No.3: (Commenter selected Alternative 2) I have concerns regarding the disposal areas. My concern is based on what information was provided and the possibility of disposal areas leaking into the surrounding area bay areas. I am concerned that leaking or leaching materials will affect the marine animals, in particular bottom feeders such as crab, clams, and catfish. What othe~ measures were available to ensure that these sites are not leaching into the ecosystem?

Response No.3: The WSIA RI Report provides extensive details regarding the results of surface media sampling conducted throughout the WSIA. Although various constituents were detected throughout the investigation area in surface media and groundwater, none exhibited a consistent and elevated pattern to distinguish any source(s) or pattern(s) of migration. The WSIA risk assessments further concluded that there were no concerns for potential ecological receptors exposure to surface soil, sediment, and surface water at the WSIA. Therefore, toxicity levels for these receptors exposed to WSIA surface media are already at low to non-existent levels. APG believes that Alternative 2 (LUCs) is protective of hwnan health and the environment. To ensure the long-term effectiveness of the remedial response, APG will perform a review of the remedy for the WSIA every five years.

Comment No.4: (Commenter selected Alternative 2) My understanding was that bomb testing was to cease in the Aberdeen Proving Ground and technical personnel were to be moved to the area to conduct other research. Yet, we still are rocked by explosions from your area. Aren't these creating new environmental hazards? Please address the continued bomb/explosion testing in a future mailing.

Response No.4; APG appreciates your feedback and agrees that the preferred alternative is the best solution for this site. While indoor research and development facilities exist at APG, APG's primary mission still involves the outdoor testing and development of weapon systems, munitions, vehicles, and a wide variety of military support material. The environmental cleanup program is limited by DoD regulations on how and when it can address ordnance items. However, there are other DoD programs which address ordnance items and the potential environmental hazards associated with ordnance testing operations. APG will continue to keep the community informed about its testing programs via mailings and outreach programs.

Comment No.5: (Commenter selected Alternative 2) The presence of heavy metals is especially troublesome in the view of the proximity of this land to the bay. HeaVy metal contamination in shellfish is particularily damaging to the oyster industry. The sampling technique that could miss other potential hot spots also supports LUC.

Response No.5: APG acknowledges the comment and will be putting controls in place to prevent future residential development unless further studies are conducted.

Comment No.6: (Commented selected Alternative 2) Having no action is not a good option.

Response No.6: APG appreciates your comment on our action for the WSIA and agrees Record ofDecision Final OEA Western Shore Investigation Area August 2011 Aberdeen Proving Ground, Maryland Page 47 that Alternative 2 provides the best solution to protect human health and the environment rather than no action at this time.

Comment No.7: (Commenter selected Alternative 2) This is the way to go. You are right on track. I concur.

Response No.7: APG appreciates the feedback and agrees with the comment.

Comment No.8: (Commenter selected Alternative 2) Until all danger to government workers and contractors are gone land use controls (LUCs) must be continued. Keep up the good work to keep our workforce safe.

Response No.8: APG believes that the preferred alternative (LUCs) is protective of human health and the environment. The WSIA risk assessments did conclude that there were no concerns for current and future military/industrial worker exposures to surface water, sediment, and surface soil at the WSIA. Implementation of the LUC remedy will eliminate the principal human health risk at the WSIA through the restriction of future residential land use that would result in unacceptable exposure.

COMMENTS FROM PUBLIC MEETING

No written comments were submitted at the public meeting and no oral comments were made. ,.,

Record ofDecision Final OBA Western Shore Investigation Area August 2011 Aberdeen Proving Ground, Maryland Page 48

PART 4: REFERENCES

Aberdeen Proving Ground (APG). 2004. Synopsisfor Other EdgewoodAreas Project Team Meeting, February 2004.

EA Engineering. Science, and Technology, Inc. (EA). 2008a. Other Edgewood Areas, Baseline Human Health Risk Assessment for the Western Shore Investigation Area. APG:MD.

2008b. Screening-Level Ecological RiskAssessment and Baseline Risk Assessment Problem Formulationfor the Western Shore Investigation Area. APG:MD.

2008c. Memorandum from EA to DSHE (Mr. John Paul), Subject: "Human Health Risk Assessment for the Western Shore Investigation Area, Other Edgewood Areas Study Area."

General Physics Corporation (GP). 2011a. Western Shore Investigation Area Remedial Investigation Report, Other EdgewoodAreas, APG. APG: MD.

--. 2011 b. Western Shore Investigation Area Focused Feasibility Study, Other EdgewoodAreas, APG. APG: MD.

ICF Kaiser Engineers. 1997. Habitat Characterization ofAberdeen Proving Ground, Maryland. APG: MD.

U.S. Anny Environmental Hygiene Agency (USAEHA). 1989. Resource Conservation and Recovery Act Facility Assessment for the Edgewood Area of Aberdeen Proving Ground, Maryland. Report No. 39-26-0490-90. APG, MD: U.S. Department ofthe Anny.

U.S. Environmental Protection Agency (USEPA). 1997. Ecological Risk Assessment Guidance for Superfund: Process for Designing and Conducting Ecological Risk Assessments. USEPA. Washington, D.C.

--. 1999. A Guide to Preparing Superfund Proposed Plans, Records ofDecision, and Other Remedy Selection Decision Documents. EPA 540-R-98-031.

--. 2008. Regional Screening Levels for Chemical Contaminants at Superfund Sites. USEPA online at http://epa-prgs.oml.gov/chemicalslindex.shtml. Accessed 17 June 2008.

USEPA Region III, APG, and U.S. Department of the Anny. 1990. Federal Facility Agreement under CERCLA Section 120, Aberdeen Proving Ground, Maryland. Administrative Docket Number III-FCA-CERC-004. USEPA Region II~ and U.S. Department ofthe Anny. RecordofDecision Final OEA Western Shore Investigation Area August 2011 Aberdeen Proving Ground, Maryland Page 49

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