Installation Restoration ProgramInstallation Restoration Program

OTHER ABERDEEN AREAS

Record of Decision

Pistol Range, Known Distance Range and 23 Other Sites

Final

August 2007

U.S. Army GarrisonAberdeen Proving Ground, Maryland

DISTRIBUTION RESTRICTIONSTATEMENT APPROVED FOR PUBLIC RELEASE:DISTRIBUTION IS UNLIMITED#6825-A-6

Record of Decision For the Pistol Range, Known Distance Range

and 23 Other Sites

Other Aberdeen Areas, Aberdeen Area Aberdeen Proving Ground, Maryland

FINAL

Directorate of Safety, Health, and Environment Environmental Conservation and Restoration Division

Aberdeen Proving Ground, Maryland

August 2007

i

CONTENTS Page

LIST OF FIGURES ....................................................................................................................... iv LIST OF TABLES...........................................................................................................................v LIST OF ACRONYMS AND ABREVIATIONS ......................................................................... vi

1. DECLARATION .................................................................................................................1 1.1 Site Name and Location ..........................................................................................1 1.2 Statement of Basis and Purpose...............................................................................2 1.3 Assessment of the Two Former Small Arms Range Sites and 15 LUC Sites..........2 1.4 Description of the Selected Remedies .....................................................................3 1.5 Statutory Determinations .........................................................................................4 1.6 Data Certification Checklist.....................................................................................4 1.7 Authorizing Signatures and Support Agency Acceptance of Selected Remedy......5 2. THE DECISION SUMMARY ............................................................................................6

2.1 Site Name, Location, and Description .....................................................................6 2.2 Site History and Enforcement Activities .................................................................6

2.2.1 Two Former Small Arms Range Sites .........................................................6 2.2.2 15 LUC Sites................................................................................................7 2.2.3 8 NFA Sites..................................................................................................8 2.3 Community Participation.........................................................................................8 2.4 Scope and Role of Response Action........................................................................9 2.5 Site Characteristics.................................................................................................10 2.5.1 Two Former Small Arms Range Sites .......................................................11 2.5.2 15 LUC Sites..............................................................................................14 2.5.2 8 NFA Sites................................................................................................28 2.6 Current and Potential Future Site and Resource Uses ...........................................34 2.7 Summary of Site Risks...........................................................................................35 2.7.1 Human Health Risk Assessment................................................................35 2.7.1.1 Identification of Contaminants of Concern................................35 2.7.1.2 Exposure Assessment .................................................................36 2.7.1.3 Toxicity Assessment ...................................................................37 2.7.1.4 Risk Characterization ................................................................37

ii

CONTENTS (continued) Page

2.7.2 Ecological Risk Assessment ......................................................................39 2.7.2.1 Identification of Contaminants of Concern ...............................39 2.7.2.2 Exposure Assessment.................................................................39 2.7.2.3 Toxicity Assessment ...................................................................40 2.7.2.4 Risk Characterization................................................................40

2.7.3 Basis for Action .........................................................................................42

2.8 Remedial Action Objectives ..................................................................................42 2.9 Description of Alternatives ....................................................................................44 2.9.1 Two Former Small Arms Range Sites .......................................................44 2.9.1.1 Alternative 1: No Action ..........................................................45 2.9.1.2 Alternative 2: Land Use Controls ............................................45 2.9.1.3 Alternative 3: OEW Clearance, Excavation, Physical Separation and Offsite Disposal ..............................................46 2.9.1.4 Alternative 4: OEW Clearance, Excavation, Soil Washing, and Offsite Disposal................................................................47 2.9.1.5 Alternative 5: OEW Clearance, Excavation, Separation, Silica Stabilization, and Offsite Disposal ................................48 2.9.1.6 Alternative 6: OEW Clearance, Excavation, Separation, Soluble Phosphate Stabilization, and Offsite Disposal............49 2.9.2 15 LUC Sites..............................................................................................49 2.9.2.1 Alternative 1: No Action ..........................................................49 2.9.2.2 Alternative 2: Land Use Controls ............................................50 2.10 Comparative Analysis of Alternatives ...................................................................50 2.10.1 Two Former Small Arms Range Sites .......................................................51 2.10.1.1 Threshold Criteria ...................................................................51 2.10.1.2 Primary Balancing Criteria .....................................................52 2.10.1.3 Modifying Criteria ...................................................................55 2.10.2 15 LUC Sites..............................................................................................55 2.10.2.1 Threshold Criteria ...................................................................55 2.10.2.2 Primary Balancing Criteria .....................................................56 2.10.2.3 Modifying Criteria ...................................................................56

iii

CONTENTS (continued) Page

2.11 Principal Threat Wastes .........................................................................................57 2.12 Selected Remedy....................................................................................................57 2.12.1 Two Former Small Arms Range Sites .......................................................57 2.12.2 15 LUC Sites..............................................................................................62 2.13 Statutory Determinations .......................................................................................63 2.13.1 Protection of Human Health and the Environment....................................64 2.13.2 Compliance With Applicable or Relevant and Appropriate Requirements .............................................................................................64 2.13.3 Cost Effectiveness......................................................................................65 2.13.4 Utilization of Permanent Solutions and Alternative Treatment

Technologies (or Resource Recovery Technologies) to the Maximum Extent Practicable ......................................................................................66 2.13.5 Preference for Treatment as a Principal Element ......................................66 2.13.6 Five Year Review Requirements ...............................................................66 2.14 Documentation of Significant Changes from Preferred Alternative on Proposed Plan.........................................................................................................66 3. RESPONSIVENESS SUMMARY....................................................................................68 3.1 Overview................................................................................................................68 3.2 Background on Community Involvement..............................................................69 3.3 Summary of Comments Received During the Public Comment Period and Army Responses ....................................................................................................70 4. REFERENCES ..................................................................................................................72 APPENDIX A: SAMPLE NEWSPAPER NOTICE

iv

LIST OF FIGURES

Number Title

1 Aberdeen Proving Ground, Aberdeen, Maryland – Area Map. 2 Pistol Range/Known Distance Range, IRP Sites 30a and 30b − Site Location Map. 3 Site 3: Churchville Test Course Dump – Site Location Map. 4 Sites 4, 5, 6, 7, 10, 11, 13, 14, 15, 18, 19, 21, 22, 24, 28a, 28b, 28c, 28d, and 28e -

Site Location Map. 5 Sites 20, 27, and 31 − Site Location Map. 6 Site 30a: Pistol Range – Sampling Locations. 7 Site 30b: Known Distance Range – Sampling Locations. 8 Site 30a: Pistol Range – Estimated Area Exceeding Remedial Goals and Land Use

Control Boundary. 9 Site 30b: Known Distance Range – Estimated Area Exceeding Remedial Goals

and Land Use Control Boundary.

10 Schematic Diagram of Soil Washing Separation Process

11 Land Use Control Sites: Sites 4, 5, 7, 10, 21, 28c, 28d and 28e – Land Use Control Boundaries.

12 Land Use Control and No Further Action Sites: Sites 6, 11, 13, 14, 15, 18, 19, 22,

24, 28a and 28b – Land Use Control Boundaries. 13 Land Use Control and No Further Action sites: Sites 20, 27 and 31 – Land Use

Control Boundaries.

v

LIST OF TABLES

Number Title

1 Conceptual Site Model – Two Former Small Arms Firing Range Sites. 2 Risk Summary for Primary COCs Contributing to Cancer and Non-Cancer

Hazards for the Pistol Range (Site 30a). 3 Risk Summary for Primary COCs Contributing to Cancer and Non-Cancer

Hazards for the Known Distance Range. 4 Chemicals of Concern for Ecological Receptors. 5 Final Risk-Based Remedial Goals. 6 Estimated Soil Volumes Exceeding RGs. 7 Comparative Analysis Summary of Remedial Alternatives, Site 30a: Pistol Range

and Site 30b: Known Distance Range. 8 Alternative 4 – Excavation, Soil Washing, and Onsite Disposal 9 Summary of Restrictions for the 23 Sites, Other Aberdeen Areas, APG, MD 10 ARARs⎯Action/Location-Specific Applicable or Relevant and Appropriate

Requirements.

vi

LIST OF ACRONYMS AND ABBREVIATIONS

AA Aberdeen Area APG Aberdeen Proving Ground APGSCC Aberdeen Proving Ground Superfund Citizens Coalition ARAR Applicable or Relevant and Appropriate Requirement ARL Army Research Laboratory AST Aboveground Storage Tank ATC Aberdeen Test Center AWQC Ambient Water Quality Criteria BERA Baseline Ecological Risk Assessment bgs Below Ground Surface BRA Baseline Risk Assessment BTAG Biological Technical Assistance Group BTD Bomb Throwing Device BTEX Benzene, Toluene, Ethylbenzene, and Xylene CERCLA Comprehensive Environmental Response, Compensation, and Liability Act CFR Code of Federal Regulations CLP Contract Laboratory Program COC Contaminant of Concern COMAR Code of Maryland Regulations COPC Contaminant of Potential Concern CWA Chemical Warfare Agent DCE Dichloroethene DDTr Daughter Products DPW Department of Public Works DRMO Defense Reutilization Marketing Office DSERTS Defense Site Environmental Restoration Tracking System EA EA Engineering, Science, and Technology, Inc. EO Executive Order ER−M Effects Range−Medium FFA Federal Facilities Agreement FS Feasibility Study ft Foot or Feet ft2 Square Foot or Square Feet GAC Granular Activated Carbon GPS Global Positioning System HE High Explosives

vii

LIST OF ACRONYMS AND ABBREVIATIONS (continued)

HEAST Health Effects Assessment Summary Tables HHRA Human Health Risk Assessment HI Hazard Index HMX High Melting Explosive HQ Hazard Quotient IA Installation Assessment in. Inch(es) IRIS Integrated Risk Information System IRP Installation Restoration Program KD Known Distance LDR Land Disposal Restriction LECR Lifetime Excess Cancer Risk LOAEC Low Adverse Effects Concentrations LOAEL Low Adverse Effects Levels LUCs Land Use Controls MCL Maximum Contaminant Levels MDE Maryland Department of the Environment mg/kg Milligram(s) Per Kilogram NCP National Oil and Hazardous Substance Pollution Contingency Plan NFA No Further Action NOAEC No Adverse Effects concentration NPL National Priorities List OAA Other Aberdeen Areas OEW Ordnance and Explosive Waste O&M Operation and Maintenance OSHA Occupational Safety and Health Administration’ OU Operable Unit PAH Polycyclic Aromatic Hydrocarbons PCB Polychlorinated Biphenyl pCi/L PicoCurie(s) Per Liter PCE Tetrachloroethene POL Petroleum, Oil, and Lubricants PPL Priority Pollutant List PRG Preliminary Remediation Goal RA Risk Assessment RAB Restoration Advisory Board

viii

LIST OF ACRONYMS AND ABBREVIATIONS (continued)

RAO Remedial Action Objective RBC Risk-Based Concentration RCRA Resource Conservation and Recovery Act RDX Royal Demolition Explosive RFA RCRA Facility Assessment RfD Reference Dose RG Remediation Goal RI Remedial Investigation ROD Record of Decision SARA Superfund Amendments and Reauthorization Act SEP Sequential Extraction Procedure SPLP Synthetic Precipitation Leaching Procedure SVOC Semivolatile Organic Compound SWMU Solid Waste Management Unit TAL Target Analyte List TCA Trichloroethane TCE Trichloroethene TCL Target Compound List TCLP Toxicity Characteristic Leaching Procedure TNT Trinitrotoluene TPH Total Petroleum Hydrocarbons TSCA Toxic Substances Control Act UCLM Upper Confidence Limit on the Mean μg/dL Microgram(s) Per Deciliter μg/kg Microgram(s) Per Kilogram μg/L Microgram(s) Per Liter USDOT United States Department of Transportation USEPA United States Environmental Protection Agency UST Underground Storage Tank UXO Unexploded Ordnance VOC Volatile Organic Compound WBSA Western Boundary Study Area WES Waterways Experiment Station WPLBA White Phosphorous Land Burial Area WPUMBA White Phosphorous Underwater Munitions Burial Area XRF X-Ray Fluorescence yd Yard(s) yd3 Cubic Yard(s)

1

1. DECLARATION 1.1 SITE NAME AND LOCATION Two former small arms range sites, Site 30a: Pistol Range and Site 30b: Known Distance Range, located in the Aberdeen Area (AA) of Aberdeen Proving Ground (APG), Maryland, require remedial action under the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) to address contaminated soils. In addition to the two former small arms range sites, this Record of Decision (ROD) addresses 23 Other Aberdeen Areas (OAA) sites. These 23 sites will require either limited action [Land Use Controls (LUCs)], preventing future military family housing, elementary and secondary schools, child care facilities, playgrounds, and non-military residential land use, or warrant No Further Action (NFA). Fifteen of the 23 sites will require LUCs and will be collectively referred to as the “15 LUC Sites.” Eight of the 23 sites warrant no additional investigation or remediation and will be referred to as the “8 NFA sites.” The two former small arms range sites and the 23 Sites are associated with the Michaelsville Landfill National Priorities List (NPL) Site – Superfund Site ID Number MD3210021355. The sites are listed below: Two Former Small Arms Range Sites • Site 30a: Pistol Range • Site 30b: Known Distance Range 15 LUC Sites • Site 4: Outdoor Pesticide Mixing Area at Building 5010 • Site 5: Department of Public Works (DPW) Backyard Storage Area Near Building 5262 • Site 6: DDT Spill Near Building 450 • Site 7: Spent Lead Acid Battery Site Near Building 2351 • Site 10: Building 5039 Battery Shop • Site 11: Old Burn Trench on Spesutie Island • Site 18: Barrels Near Building 510 • Site 19: Sandblast Area Near Building 523 • Site 20: Potential Explosives in Groundwater Area • Site 21: Petroleum, Oil, and Lubricants (POL) Facility Sand Pit Near Building 5215 • Site 22: Buildings 309 and 390 Storm Sewer Outfalls • Site 27: German Ammunition Train Explosion Area • Site 28c: Building 2458 Underground Storage Tank (UST) Site • Site 28d: Building 3329 UST Site • Site 28e: Building 3505 UST Site

2

8 NFA Sites • Site 3: Churchville Test Course Dump • Site 13: Chemical Dump Ponds on Spesutie Island • Site 14: Former Burning Area Near Building 1171 • Site 15: Metal Barricade Near Building 1122 • Site 24: White Phosphorous Munitions Land Burial Area • Site 28a: Building 436 UST Site • Site 28b: Building 456 Aboveground Storage Tank (AST) Site • Site 31: Poverty Island Potential Mine Burial Site 1.2 STATEMENT OF BASIS AND PURPOSE This ROD presents the Selected Remedy addressing the two former small arms range sites (Site 30a: Pistol Range and Site 30b: Known Distance Range) requiring action, the 15 LUC Sites that require limited action (LUC), and the 8 NFA Sites within the OAA. The remedial action selected for the two former small arms range sites 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 (NCP). The information supporting the decisions on the Selected Remedies is contained in the administrative record for APG. The 15 LUC Sites do not require further response action based on a reasonably anticipated industrial/military exposure scenario; however, to support the reasonably anticipated future use of the site for industrial/military purposes, a use restriction will be implemented by the Installation at these 15 sites to prohibit non-military residential land use, childcare, schools, playgrounds, and military family housing. The U.S. Department of the Army (site owner) is the lead agency for the two former small arms range sites and the 23 Sites. The Army together with the U.S. Environmental Protection Agency (USEPA) are issuing this ROD selecting the remedial action for the two former small arms range sites and LUCs for the 15 LUC Sites, and are making NFA determinations for the 8 NFA Sites. These actions have been coordinated with the State of Maryland, represented by the Maryland Department of the Environment (MDE), who accepts the Selected Remedies. To complete a streamlined response, USEPA and MDE support the Selected Remedy as necessary to adequately and cost-effectively protect human health and the environment. 1.3 ASSESSMENT OF THE TWO FORMER SMALL ARMS RANGE SITES AND 15 LUC SITES The response actions selected in this Record of Decision are necessary to protect the public health or welfare or the environment from actual or threatened releases of hazardous substances into the environment.

3

1.4 DESCRIPTION OF THE SELECTED REMEDIES Two Former Small Arms Range Sites Soils at the Pistol Range and Known Distance Range have been impacted by site-specific contaminants, which resulted from prior activities that have occurred at each site. In conjunction with previous characterization efforts, the results of the Phase I Remedial Investigation (RI) (URS 2002), Final Phase II RI (EA 2005a), Human Health Risk Assessment (HHRA) (EA 2005b), and the Baseline Ecological Risk Assessment (BERA) (EA 2005c) reports were used to delineate areas impacted by the contaminants of concern (COCs). The COCs identified in soil at each site are as follows:

• Site 30a: Pistol Range − antimony, arsenic, copper, and lead • Site 30b: Known Distance Range − antimony, copper, lead, mercury, and zinc

These COCs are considered to be a threat to human health and/or the environment. The Feasibility Study (FS) was prepared to evaluate the remedial alternatives as discussed in this document in order to address the impacted soil at each of the two sites. The components of the selected remedial action (Alternative 6 – Ordnance and Explosive Waste [OEW] Clearance, Excavation, Stabilization, Offsite Disposal, and LUCs) include soil excavation and removal, offsite/off-Post disposal of contaminated soils to an approved facility, and LUCs at the two sites. The selected remedial action is intended to prevent human or ecological exposure to COCs at concentrations of potential concern and to prevent future migration of COCs in soil at the two sites. The major components of the selected remedial action are as follows:

• Conduct range clearance activities to identify and remove OEW materials from the excavation areas;

• Excavation of approximately 15,368 tons of soil impacted above Remedial Goals (RGs)

(shown in the Table 5 on page 43) and separation of metal debris and particulate metal from impacted soil by physical separation techniques;

• Stabilization of excavated soil with a soluble phosphate amendment (or similar) to reduce

toxicity and bioavailability;

• Transport and disposal of impacted soil at an appropriate offsite/off-Post landfill for non-hazardous waste as well as recycling/disposal of screened metallic debris;

• Post-removal confirmation sampling of excavated areas; and

• Applying LUCs to prevent military family housing, non-military residential housing, elementary and secondary schools, child-care facilities, and playground land use.

4

15 LUC Sites Results of the previous Resource Conservation and Recovery Act (RCRA) Facilities Assessment (APG 1990), Installation Assessment of Aberdeen Proving Ground-Aberdeen Area (APG 1981), Phase I (URS 2002) and Phase II (EA 2005a) RIs, and additional sampling efforts for risk assessment purposes at the 15 LUC Sites revealed that these sites did not warrant further investigation or response, because there were no unacceptable risks identified for human health (under the reasonably anticipated industrial/military land-use scenario) or for ecological receptors. To support the reasonably anticipated future use for industrial/military purposes, a use restriction will be implemented by the Installation at 15 sites to prohibit non-military residential land use, childcare, schools, playgrounds, and military family housing. 8 NFA Sites Results of the previous environmental investigations at the 8 NFA Sites revealed that these sites did not warrant further investigation or response, because there were no unacceptable risks identified for human health or for ecological receptors. No response action(s) are warranted and these sites will remain with unrestricted use. 1.5 STATUTORY DETERMINATIONS The remedies meet the requirements of CERCLA Section 121 and, to the extent practicable, the NCP. The Selected Remedy is protective of human health and the environment, complies with Federal and State requirements that are legally applicable or relevant and appropriate to the remedial action, is cost effective, and utilizes permanent solutions to the maximum extent practicable. The Selected Remedies do not employ treatment to reduce toxicity, mobility, or volume of hazardous substances, pollutants, or contaminants. Therefore, the Selected Remedies do not satisfy the statutory preference for remedies that employ treatment as a principal element. Although the Selected Remedy for the two former small arms firing ranges sites will remove COC-impacted soil, the sites will still have residential use restrictions based on potential unacceptable residual risk for such use. Therefore, a CERCLA 121(c) 5-year review will be conducted for the two former small arms firing ranges in accordance with CERCLA to ensure that the remedies remain protective of human health and the environment. The 15 LUC Sites do not require action based on an industrial/commercial exposure scenario and the future anticipated use of the site. As part of the CERCLA 121(c) five-year review for the Two Former Small Arms Firing Ranges, the Army will also confirm that the residential use restrictions remain in place at the 15 LUC sites. 1.6 DATA CERTIFICATION CHECKLIST The following information is included in the Decision Summary section of this ROD. Additional information can be found in the Administrative Record file for the two former small arms range sites and the 23 Sites.

6

2. THE DECISION SUMMARY 2.1 SITE NAME, LOCATION, AND DESCRIPTION APG is located on the Chesapeake Bay, approximately 15 miles northeast of Baltimore, Maryland. APG covers approximately 72,000 acres (including water) of Harford and Baltimore counties (Figure 1). It is bordered to the east and south by the Chesapeake Bay; to the west by Gunpowder Falls State Park and residential areas; and to the north by the towns of Edgewood, Magnolia, Aberdeen, and Perryman. APG consists of two distinct and separate portions, the Aberdeen Area and the Edgewood Area. The two former small arms range sites (Figure 2), the 15 LUC Sites (Figures 3, 4, and 5), and the 8 NFA Sites (Figures 4, 5, and 6) are located within the Aberdeen Area (AA) of APG, known as the Other Aberdeen Areas (OAA), which is associated with the Michaelsville Landfill National Priorities List (MD3210021355). The land surrounding APG is used for farming and industry, but also includes residential areas. Industry is most concentrated along Route 40 through Baltimore and Harford counties. Residential areas are predominantly new town houses and developments located in Harford County. This ROD addresses two former small arms range sites that require remedial action, the 15 LUC Sites that require limited action (i.e., land use restrictions) based on the reasonably anticipated future restricted use of the sites for industrial and/or military purposes, and 8 NFA Sites that require No Further Action. 2.2 SITE HISTORY AND ENFORCEMENT ACTIVITIES The AA of APG was established as an ordnance proving ground, and throughout its history has been the site of testing conventional weapons, ammunition, armored vehicles, and other equipment. The OAA are expected to remain under military authority with testing and training activities currently being conducted. CERCLA activities at APG are being conducted under a Federal Facilities Agreement (FFA) with USEPA, signed in March 1990. The following sections briefly describe historical operations and impacts to site media as a result of these operations at the two former small arms range sites, the 15 LUC Sites, and the 8 NFA Sites. The information presented for the sites represents a compilation of previous site investigations. Detailed descriptions of site history, characteristics, and land use at the two former small arms range sites, the 15 LUC Sites, and the 8 NFA Sites are presented in the Phase I RI Report (URS 2002), the Phase II RI Report (EA 2005a), and the FS (EA 2005d). 2.2.1 TWO FORMER SMALL ARMS RANGE SITES Site 30a: Pistol Range The Pistol Range is located in the southeastern portion of the unrestricted area of APG approximately 1,300 feet (ft) northwest of Michaelsville Road (Figure 2). The Ordnance Center and School was the main user of the Pistol Range; however, the exact time of operation is

Figure 1

Area Map

Figure 2

Land Use Control Sites: Sites 4, 5, 7, 10, 21, 28c, 28d, and 28e Site Location Map

Figure 3

Land Use Control and No Further Action Sites: Sites 6, 11, 13, 14, 15, 18, 19, 22, 24, 28a, and 28b Site Location Map

Figure 4

Land Use Control and No Further Action Sites: Sites 20, 27, and 31 Site Location Map

Figure 5

No Further Action Site:Site 3 Churchville Test Course Dump Site Location Map

Figure 6

Site 3: Churchville Test Course Dump

7

unknown. In 1952, the Pistol Range was used primarily by the APG Marksmanship Group, after-hours and on weekends. Firing was limited to small caliber handguns. The use of the range was discontinued during the 1960s due to the build-up and increased activity in the 5100 block area. Much of the site is currently overgrown with vegetation. The site was initially inspected during a Phase I RI scoping visit in December 1998 (URS 2002). During Phase I, small caliber bullets were observed in and around the impact berm and side berms, confirming the site’s former use as a pistol range. Based on historical uses of the site and previous site investigations, the principal contaminants that have been detected at the site include antimony, arsenic, copper, lead, mercury, vanadium, and zinc in surface soils (0-6 inches [in.] below ground surface [bgs]). Site 30b: Known Distance Range The Known Distance Range is located in the central portion of the restricted area of APG approximately 1,200 ft west of Old Baltimore Road (Figure 2). Site history information was obtained from John H. Conley, a former APG Range Control Officer (Conley 1997). The Known Distance Range was in full operation after 1939 until early 1965, and was operated by the Ordnance Center and School as a standard Army range facility with 100-, 200-, and 300-yard (yd) firing lines. According to the APG Safety Regulation dated 1947, firing was limited to 30-caliber, shoulder-fired weapons using ball ammunition, M2s and tracer M2s, 22-caliber rifles, 30-caliber carbines, 45-caliber pistols and revolvers, and 45-caliber submachine guns. Weapons were fired from the eastern side of the open area at targets on the western side.

Based on historical uses of the site and previous site investigations, the principal contaminants that have been detected at the site include antimony, copper, lead, and zinc in surface soils (0-6 in. bgs) and sediments. 2.2.2 15 LUC SITES The Phase I and Phase II RIs were completed in 2002 and 2005, respectively, and investigated the 15 LUC Sites. Sampling within these sites revealed only sporadic and isolated detections of various chemicals, such as metals, semivolatile organic compounds (SVOCs), volatile organic compounds (VOCs), and pesticides in soils and sediments. In isolated instances groundwater concentrations have also exceeded groundwater screening criteria at some of the sites. Removal actions have been performed at some sites prior to or concurrent with the RIs. Additional risk characterization samples were also collected from some of the sites for laboratory analysis or evaluated using bioassays. The results of the RIs and risk sampling efforts showed that these sites did not warrant further investigation, since there were no unacceptable risks identified for human health (under an industrial land-use scenario) or for ecological receptors. However, historical data did indicate that contaminant concentrations in soil at some of the sites are above screening criteria that would not allow for unrestricted future land use.

8

2.2.3 8 NFA SITES Results of the previous Phase I and Phase II RIs at the 8 NFA Sites revealed that these sites did not warrant further investigation, because there were no unacceptable risks identified for human health or for ecological receptors. No response action(s) are warranted and these sites will remain with unrestricted use. 2.3 COMMUNITY PARTICIPATION Community relations activities that have taken place at APG to date include monthly Restoration Advisory Board (RAB) meetings, APG Superfund Citizens Coalition (APGSCC) meetings, public meetings and site tours, as well as press releases, and public access to the APG website. Administrative Record – Consistent with requirements of CERCLA Section 113(k), an Administrative Record containing information associated with CERCLA cleanup activities at APG is available to the public. The locations, contact information, and hours of operation for the Administrative Record file are as follows:

Harford County Library − Aberdeen Branch 21 Franklin Street

Aberdeen, MD 21001 (410) 273-5608 Hours: Monday, Tuesday, and Thursday 10 a.m. to 8 p.m. Wednesday 1 p.m. to 8 p.m. Friday and Saturday 10 a.m. to 5 p.m. Sunday 1 p.m. to 5 p.m. (October-May only) Harford County Library − Edgewood Branch 2205 Hanson Road Edgewood, MD 21040 (410) 612-1600 Hours: Monday, Tuesday, and Thursday 10 a.m. to 8 p.m. Wednesday 1 p.m. to 8 p.m. Friday and Saturday 10 a.m. to 5 p.m. Sunday Closed

Washington College Clifton M. Miller Library Kent County Chestertown, MD 21620 (410) 778-7280

Hours: Monday through Thursday 8:15 a.m. to 12 a.m. Friday 8:15 a.m. to 10 p.m. Saturday 10 a.m. to 10 p.m.

Sunday 12 p.m. to 12 a.m.

9

Mailing List – A mailing list of all interested parties in the community is maintained by APG and updated regularly. Fact Sheet – A fact sheet describing the status of the Installation Restoration Program was last distributed to the mailing list addressees on 14 September 2006. Proposed Plan – The Proposed Plan regarding the remedial actions for the Pistol Range and Known Distance Range and 23 Other Sites was made available to the public for their comments. The FS and Proposed Plan for the Pistol Range, Known Distance Range, and 23 Other Sites (Proposed Plan only) were made available to the public in June 2005 and September 2006, respectively. They can be found in the Administrative Record file and the information repository maintained at the USEPA Docket Room Region III and the public libraries of Harford County. The notice of availability of the Proposed Plan was published in newspapers, including The Aegis on 1 September 2006; The Avenue, the Kent County News, and The Cecil County Whig on 4 September 2006. A public meeting was held on 21 September 2006 at the Aberdeen Senior Center, located at 7 Franklin Street, in Aberdeen, Maryland, to present the Proposed Plan. At this meeting, representatives from the Army, USEPA, and MDE answered questions about problems at the site and the remedial alternatives. The Army and USEPA also used this meeting to solicit a wider cross-section of community input. A response to comments received during this period is included in the Responsiveness Summary, which is a part of this ROD. 2.4 SCOPE AND ROLE OF RESPONSE ACTION The Other Aberdeen Areas are associated geographically with the Michaelsville Landfill. The Michaelsville Landfill is the only site actually included in the NPL listing, but the entire surrounding northern area of the Installation is being addressed under the FFA. The northern area of the Installation is separated from the Edgewood Area by the Bush River. The entire southern area (Edgewood Area) is a separate NPL Site. The Solid Waste Management Units (SWMUs) identified in the northern area of the Installation were identified by a RCRA Facility Assessment (RFA) and were given Defense Site Environmental Restoration Tracking System (DSERTS) identification numbers by the Army. Originally, these units would have been addressed by MDE under the RCRA program. The Army later agreed to address these RCRA SWMUs under the RCRA/CERCLA integration policy, and the Army’s responsibilities for addressing these SWMUs under Superfund are detailed in the FFA. For administrative convenience, the northern area was divided into the Michaelsville Landfill area, the Western Boundary Area, and the Other Aberdeen Areas study groups. The Army is the Lead Agency, USEPA is the support agency, and MDE is the state regulatory agency. The Michaelsville Landfill has two RODs, Operable Unit 1 (OU1) (the landfill) issued in June 1992 and OU2 (all media at the site) issued in September 1997. Construction was completed in 1994 and long-term monitoring is currently being performed.

10

The Western Boundary Study Area (WBSA) consists of two OUs and is also included in the Michaelsville NPL listing. OU1 has a ROD dated July 2000 which required the installation of a carbon adsorption system on the Harford County production wells and long-term monitoring. A ROD for WBSA-OU2 has not yet been prepared. Future RODs to be prepared for the OAA include a ROD for two Landfills (Old Dump on Swan Creek and Old Dump on Woodrest Creek), and a ROD for the Shell Washout Wastewater Facility at Building 700B. Two RODs were prepared in 2006 for the OAA and include one ROD for Six Groundwater Sites (Defense Reutilization Marketing Office [DRMO] Metal Scrap Yard, Building 525 Site, Building 3327 UST Site, Tower Road Site, Building 507 Site, and Building M600 Site) (EA 2006a) and one ROD for Five Sediment Sites (Discarded Batteries at Abbey Point Navigation Light, Discarded Batteries at Spesutie Island Navigation Light, Old Chemical Dump on Spesutie Island, DRMO Metal Scrap Yard, and Silver Contaminated Ditch in Transonic Range Area) (EA 2006b). This ROD presents the final remedy for the two former small arms range sites warranting remediation (Pistol Range and Known Distance Range), related to elevated concentrations of site-specific COCs in soils at both sites and also sediment at the Known Distance Range; and the 23 Sites where no or limited additional response action (i.e., LUCs) will be taken. The activities selected in this ROD will address COC-impacted soil directly associated with past activities at the two former small arms range sites; an FS was prepared to evaluate remedial alternatives to address the contaminated soils (EA 2005d). 2.5 SITE CHARACTERISTICS The region surrounding APG extends across two physiographic provinces, the Piedmont Plateau and the Coastal Plain. The Piedmont is characterized by rolling to hilly terrain, and the Coastal Plain is generally characterized by a low-lying, gently rolling terrain. The AA, where the Pistol Range and Known Distance Range are located, is situated in the Coastal Plain Physiographic Province and occupies a large peninsula that extends into the Chesapeake Bay just south of the mouth of the Susquehanna River. The Coastal Plain Physiographic Province is characterized by marine and non-marine sediments consisting of clay, silt, sand and gravel, coarsening with depth. The regional geology is very complex, heterogeneous, and spatially variable, making it difficult to correlate the aquifers and confining units. Regional groundwater flow is generally southeast towards the Chesapeake Bay. Regional surface waters in Baltimore County, Harford County, and Cecil County include both freshwater and estuarine (mixture of fresh and salt water) systems and consist of rivers, estuarine creeks, freshwater creeks, estuarine marshes, freshwater marshes, freshwater ponds, and ephemeral ponds. Regional surface water flows toward the Chesapeake Bay, following the topography. Flow and volume in major rivers of the region range widely.

11

2.5.1 TWO FORMER SMALL ARMS RANGE SITES Based on previous site investigations that have been performed at the two former small arms range sites, it has been determined that surface soils at both of the sites, and also sediment at the Known Distance Range, are impacted with site-specific COCs. The following discussion includes characteristics specific to each site. Table 1 presents a conceptual site model illustrating contaminant sources, release mechanisms, exposure pathways, migration routes, and potential human and ecological receptors at each site. Site 30a: Pistol Range The Pistol Range is a 3-acre site consisting of a 1,000-ft back berm with four side berms, spaced every 250 ft. These berms extend approximately 100 ft towards Pistol Road. On the northwest end of the range berm, the ground level slopes down to Romney Creek, located approximately 300 ft away. Pistol Road enters into the firing locations from the northeast, and Building 5113 is located at the southeast end of the main berm. The soil berms are approximately 10 to 15 ft high. Debris associated with hanging targets and construction is located near the southern end of the main berm. There is a 10-ft by 10-ft shallow depression that catches water during heavy rain events behind the southern end of the main berm near the southernmost side berm. Historical environmental investigations at the Pistol Range have included a Phase I RI, a Phase II RI, and a Risk Assessment (RA) investigation, during which soil, sediment, and groundwater samples were collected. Sample locations are presented on Figure 7. The area of investigation was an approximate 3-acre area. Three groundwater samples were collected behind the berm during the Phase I RI and were submitted for laboratory analysis of VOCs, SVOCs, Target Analyte List (TAL) metals, cyanide, and chemical warfare agent (CWA) degradation products. No analytes were detected in groundwater at concentrations equal to or greater than the tap water Risk-Based Concentration (RBC). To further assess potential impacts to groundwater from lead in the berms, one composite soil sample was collected and submitted for total and Synthetic Precipitation Leaching Procedure (SPLP) analysis in April 2007. SPLP analysis is similar to the Toxicity Characteristic Leaching Procedure (TCLP) analysis that simulates leachate concentrations under a landfill scenario. However, SPLP analysis simulates leachate concentrations under a region-specific groundwater infiltration scenario. Therefore, the extraction fluid for SPLP analysis is more representative of rainwater, which is less acidic than landfill leachate, and generates more representative leachate concentrations from natural site processes rather than in a landfill environment. The lead concentration from the SPLP analysis was 29 micrograms per liter (μg/L). To calculate the target leachate concentration that would result in a site groundwater concentration of 15 μg/L (the MCL for lead), the USEPA Soil Screening Guidance (USEPA 1996) mass-limited methodology was utilized. Utilizing the methodology, the target leachate concentration is calculated by utilizing the lead MCL (15 μg/L) multiplied by the Dilution Factor. Based on site and region specific data including infiltration (12 in/yr), hydraulic

12

conductivity (165 ft/day), and hydraulic gradient (1.60x10-3), the Dilution Factor for the Pistol Range was calculated to be 12.18. A leachate concentration of 183 μg/L, which is greater than the SPLP sample leachate concentrations (29 μg/L), was calculated that would result in a groundwater concentration of 15 μg/L. Therefore, based on the previous groundwater samples collected and the SPLP analysis results, lead impacts to groundwater quality (if any) would likely be minor. Surface soils (0-6 in. bgs) surrounding the impact and side berms at the site are contaminated with metals, primarily consisting of (highest detected concentrations in parentheses) antimony (3,180 milligrams/kilogram [mg/kg]), arsenic (1,150 mg/kg), copper (187 mg/kg), lead (1,490 mg/kg), mercury (0.19 mg/kg), vanadium (38.1 mg/kg), and zinc (137 mg/kg). Assessment of contaminant data indicates that there are approximately 830 cubic yards (yd3) of COC-impacted surface media at the site. Site 30b: Known Distance Range The Known Distance Range is an approximate 46-acre site. Currently, 75 percent of the site is wooded. While active, the site consisted of a flat open field, 1,500 ft wide (north to south) by 1,000 ft deep (west to east). The backstop berms on the site are situated northwest to southeast with the firing locations situated to the northeast. An offshoot of Palmer Road runs parallel to the northwest end of the site with Building 860 located across the road from the site. The sighting ranges at the Known Distance Range are located at the eastern corner of the site. A drainage ditch runs from behind the berms to the southeast and downgradient to Romney Creek. There are two main impact areas towards the middle of the back berm that are relatively bare of vegetation and very sandy; many bullets were observed on the surface of the berms during the December 1998 Phase I Scoping visit. The main berm also continues along the sides of the range (the northern and southern ends), forming side berms. Historical environmental investigations at the Known Distance Range have included a Phase I RI, a Phase II RI, and an RA investigation, during which soil, sediment, and groundwater samples were collected. Sample locations are presented on Figure 8. The area of investigation was an approximate 46-acre area. Unfiltered groundwater samples were collected from three locations behind the berm during the Phase I RI. Three metals (iron, arsenic, and thallium) and two radiological analytes (total alpha and beta) were detected at concentrations equaling or exceeding the RBC criteria in the groundwater samples. Additional filtered groundwater samples were collected during the Phase II RI. Three metals (arsenic, iron, and manganese) were reported in the samples at concentrations above the RBCs but below the Maximum Contaminant Levels (MCLs). Based on a comparison of the range of detected concentrations of arsenic (4.51 to 5.92 µg/L), iron (30.4 to 17,300 µg/L), and manganese (83 to 446 µg/L) to the APG groundwater reference concentration ranges for arsenic (2.0 to 11.1 µg/L), iron (15.6 to 29,700 µg/L), and manganese (3.2 to 866 µg/L), the groundwater quality at the site is comparable to background concentrations. No radiological analytes were detected above the RBC tap water criteria in the filtered groundwater samples.

Sampling Locations

Figure 7

Soil Impact Berms

5111

5110

5115

5107

Pistol Road

5109

5113

Sampling Locations

Figure 8

Soil Backstop

Berm

860Rifle Range Road

Old Balt

imor

e Roa

d

851

13

Table 1: Conceptual Site Model – Two Former Small Arms Firing Range Sites Receptor

Human Ecological

Site

Primary Source

Primary Release

Mechanism

Secondary

Source

Secondary

Release Mechanism

Pathway

Exposure

Route Construction Worker

Commercial Worker

Trespasser Terrestrial Aquatic

Ingestion

Dermal

Soil

Inhalation (air)

Ingestion

Site 30A

Small Arms Bullets

Leaching/ Decomposition

Soil or Sediment

Erosion or Dust Release

Sediment

Dermal

Ingestion

Sediment

Dermal

Ingestion

Site 30B

Small Arms

Bullets

Leaching/

Decomposition

Sediment

Erosion

Surface Water

Dermal

14

To further assess potential impacts to groundwater from the lead in the berms, seven composite soil samples were collected and submitted for total and SPLP analysis in April 2007 similar to the Pistol range. The mean lead concentration from the SPLP analysis was 215 μg/L. To calculate the target leachate concentration that would result in a site groundwater concentration of 15 μg/L (the MCL for lead), the USEPA Soil Screening Guidance mass-limited methodology was utilized. Based on site and region specific data including infiltration (12 in/yr), hydraulic conductivity (180 ft/day), and hydraulic gradient (1.55x10-3), the Dilution Factor for the Known Distance Range was calculated to be 12.75. Therefore, a leachate concentration of 191 μg/L was calculated that would result in groundwater concentration of 15 ug/L. The conservatively calculated concentration is similar to the reported mean SPLP leachate concentration and is greater than a majority of the leachate concentrations. Therefore, based on the previous groundwater samples collected and the SPLP analysis results, lead impacts to groundwater quality (if any) would likely be minor. Surface soils (0-6 in. bgs) surrounding the impact and side berms at the site are contaminated with metals, primarily consisting of (highest detected concentrations in parentheses) antimony (677 mg/kg), copper (1,010 mg/kg), lead (17,000 mg/kg), and zinc (533 mg/kg). Assessment of contaminant data indicates that there is approximately 10,148 yd3 of COC-impacted surface media at the site. 2.5.2 15 LUC SITES The 15 LUC Sites are shown on Figures 3, 4, and 5. Site 4: Outdoor Pesticide Mixing Area At Building 5010 Building 5010 is located outside of the restricted area, in the north-central portion of APG, near Havre de Grace Street (Figure 3). Building 5010 consists of a two-story building that was formerly used as an incinerator, and was also used to store, and mix, pesticides and herbicides for application, since the mid 1970s. Presently, Building 5010 is vacant and is scheduled for demolition. A removal action was conducted by APG in July-September 1991 and resulted in the removal of 586 tons of pesticide-contaminated soil to a maximum pre-determined depth of 2 ft across the entire site. Confirmatory soil samples collected on the excavation floor showed pesticides concentrations greater than Industrial soil RBCs. The site was restored with clean fill. After the 1991 soil removal action, Phase I and Phase II RI sampling revealed a localized area of pesticide concentrations (4,4-DDD, aldrin, and dieldrin) in subsurface soil below the limits of the 1991 excavation. The pesticide concentrations reported in the Phase I and Phase II RI soil samples were above the USEPA Region III Industrial Land Use RBCs of 17 mg/kg (4,4-DDD), 0.34 mg/kg (aldrin), and 0.36 mg/kg (dieldrin). The highest concentration reported for 4,4-DDD was 133 mg/kg; for aldrin was 0.973 mg/kg; and for dieldrin was 9.45 mg/kg.

15

A limited soil removal was performed during the Phase II RI in the area adjacent to the northwest portion of Building 5010 to remove the area of elevated pesticides concentrations identified in the soil samples in that area. The excavation area was approximately 20 ft by 20 ft by 4 ft deep. After the limited soil removal action (approximately 59 yd3), no soil pesticide concentrations exceeded the industrial soil RBCs for 4,4-DDD, aldrin, and dieldrin or the Biological Technical Assistance Group (BTAG) screening concentrations (0.10 mg/kg for 4,4-DDD, aldrin, and dieldrin) in any of the five post-excavation samples. Groundwater samples were obtained for laboratory analysis from three rounds of monitoring well sampling, geoprobes, and Rotosonic borings during the Phase II RI. Two explosives (2-amino-4,6-dinitrotoluene and 4-amino-2,6-dinitrotoluene), seven unfiltered metals (aluminum, antimony, arsenic, barium, chromium, iron, and manganese), four filtered metals (arsenic, barium, iron, and manganese), and two radiological analytes (alpha and beta) were detected above tap water RBC criteria in the groundwater samples obtained from the monitoring wells. The explosive compounds were reported in one groundwater monitoring round and were not repeated in the other two sampling rounds, and the radiological contaminants were not reported above the tap water RBC criteria in the associated filtered groundwater samples. Only arsenic and barium currently have MCLs, and no reported concentrations of barium from filtered groundwater samples were reported above the MCL (2,000 µg/L). However, concentrations of arsenic in two filtered groundwater samples (12.1 and 14.5 µg/L) were reported above the MCL (10 µg/L) from the same monitoring well, G4-01-MW-3. However, the reported concentration (12.1 µg/L) from the August 2001 sampling event was reportedly biased high and the other concentration (14.5 µg/L) from the November 2001 sampling event was likely the result of laboratory cross-contamination. In addition, one VOC, trichloroethene (TCE, 0.79 µg/L), was detected above the RBC, but less than the MCL (5 µg/L) in one monitoring well groundwater sample and was not repeated during a subsequent sampling event at the sample location. One SVOC [bis(2-ethylhexyl) phthalate], 13 unfiltered metals (aluminum, arsenic, barium, beryllium, chromium, cobalt, copper, iron, lead, manganese, nickel, vanadium, and zinc), and 5 filtered metals (antimony, arsenic, barium, iron, manganese) were detected above tap water RBC criteria in the Rotosonic boring groundwater samples. The reported bis(2-ethylhexyl) phthalate concentration was likely due to laboratory cross-contamination. Gross alpha was also detected above the tap water RBC in five unfiltered groundwater samples obtained from the Rotosonic borings. Gross beta and U-238 were detected in two and one groundwater Rotosonic boring groundwater samples, respectively, at concentrations exceeding screening criteria. However, none of the associated filter groundwater samples were reported with radiological contaminants above the tap water RBC. In addition, the filtered geoprobe radiological concentrations are similar to the unfiltered groundwater sample concentration collected from adjacent monitoring wells at the same time. Therefore, elevated groundwater radiological concentration can be attributed to suspended sediments in unfiltered groundwater samples. Fourteen unfiltered metals (aluminum, arsenic, barium, beryllium, cadmium, chromium, cobalt, copper, iron, lead, manganese, mercury, nickel, and vanadium), and three filtered metals (barium, iron, manganese) were detected above USEPA Region III RBCs in the geoprobe

16

groundwater samples No filtered groundwater samples were reported with concentrations of barium above the MCL (2,000 µg/L). Based on the results of the groundwater sampling, no concentrations were reported above the MCLs with the exception of arsenic. However, it is likely that arsenic concentrations are a result of naturally occurring conditions and not from site activities based on an evaluation of the sampling results. Therefore, it does not appear that the former site activities have adversely impacted site groundwater. Subsequent to the completion of the Phase II RI, investigative results were evaluated as part of the baseline ecological risk assessment of the OAA (APG 2002). During this assessment, DDT and its daughter products (DDTr) were identified as a potential concern for ecological receptors. Additional samples were collected to confirm DDTr detections and to evaluate toxicity. DDTr was found at lower concentrations, and no toxicity was observed. In addition to the analytical results for the site, the site is relatively small and consists primarily of mowed grass and gravel parking areas that have been determined to contain limited habitat for ecological receptors. Therefore, this area is considered unlikely to pose ecological risks. From the results of the RIs including the additional limited soil removal and the baseline ecological risk assessment, no unacceptable risk to human health (under an industrial land use scenario) or to ecological receptors was identified; thus, further investigation or remediation for the site beyond the implementation of LUCs prohibiting residential land use (future military family housing, elementary and secondary schools, child care facilities, playgrounds, and non-military residential land use) is not warranted. Site 5: DPW Backyard Storage Area Near Building 5262 The DPW Backyard Storage Area is located behind Building 5262, in the north-central portion of APG, adjacent to Student Drive (Figure 3). Historically, the site was used as an equipment storage area and included the storage of electrical transformers for APG-DPW. Two removal actions have been conducted at the site and include a removal of approximately 75 yd3 of polychlorinated biphenyl (PCB) impacted soil in 1989 to a cleanup concentration of 10 mg/kg and 260 yd3 of pesticide impacted soil in 1992 to a cleanup concentration of 10 mg/kg. Confirmation sampling performed subsequent to the 1989 removal action reported no concentrations of PCBs above the cleanup level in the remaining soil. However, confirmation sampling performed after the 1992 removal action reported pesticide concentrations greater than the 10 mg/kg cleanup level in the subsurface soil (generally at depths of 6 to 24-inches below grade). Reported DDT concentrations in the confirmatory samples ranged from 0.14 to 23 mg/kg. . Soil, groundwater, and sediment samples were collected and analyzed during the Phase I and Phase II RIs. During the Phase I RI, concentrations of TAL metals were detected in groundwater samples at concentrations lower than the published MCLs, with the exception of antimony (7.7 μg/L). During the Phase II RI, a sediment sample was collected to evaluate potential offsite migration. Three pesticides (4,4-DDD [285 micrograms per kilogram (μg/kg)], 4,4-DDE

17

[1,020 μg/kg], and 4,4-DDT [110 μg/kg]) and three metals (arsenic [9.27 μg/kg], chromium [25.4 μg/kg], and lead [92.3 μg/kg]) were reported at concentrations above the BTAG criteria but below the Industrial Land Use RBCs. From the results of the RIs, no unacceptable risk to human health (under an industrial land use scenario) was identified; thus, further investigation or remediation for the site beyond the implementation of LUCs prohibiting residential land use (future military family housing, elementary and secondary schools, child care facilities, playgrounds, and non-military residential land use) is not warranted. The site generally consists of gravel pads, impervious surfaces, median strips, or mowed and disturbed fragments of lawn that do not provide the habitat necessary to support ecological receptors. Therefore, there are no complete ecological exposure pathways and no potential for risks. Site 6: DDT Spill Near Building 450 The DDT Spill near Building 450 is located in the north-central portion of the restricted area of APG (Figure 4). The site is an open area near Building 450 and the old Phillips Airfield that is used for outdoor storage of equipment and vehicles. Approximately 4,755 gallons of DDT, stored in corroded, leaky containers, were observed on the site in 1974. Prior to 1984, the containers were removed from the site, and a soil removal was performed consisting of a 40-ft by 39-ft area to a depth of 1 ft, beneath the former location of the leaky containers. Confirmatory sampling revealed one sample with elevated DDT soil concentrations. An additional soil removal action was performed in 1991 for pesticides in soil. During the Phase I RI in 2001, additional soil and groundwater sampling was performed in the area of the pre-1984 and 1991 soil removal actions. Additional sampling revealed no Target Compound List (TCL) pesticides/PCBs exceedances in groundwater, based on MCLs or tap water RBCs, or in soil, based on the Industrial Land Use RBCs. Subsequent to the completion of the Phase I RI, investigative results were evaluated as part of the baseline ecological risk assessment of the OAA (APG 2002). During this assessment, DDT and its daughter products (DDTr) were identified as a potential concern for ecological receptors. Therefore, additional soil samples were collected to confirm and bound high DDTr concentrations. The results showed that DDTr was elevated in the disturbed gravel pad, but was not elevated in surrounding mowed grass terrestrial habitat. Since concentrations are not elevated in ecological habitats and since there is no evidence that contaminant transport has or will occur from the highly compacted pad, this area is considered unlikely to pose ecological risks. From the results of the RI and the baseline ecological risk assessment, no unacceptable risk to human health (under an industrial land use scenario) or for ecological receptors was identified; thus, further investigation or remediation for the site beyond the implementation of LUCs prohibiting residential land use (future military family housing, elementary and secondary schools, child care facilities, playgrounds, and non-military residential land use) is not warranted.

18

Site 7: Spent Lead Acid Battery Site Near Building 2351 This site is located outside of the restricted area, within the northern portion of APG, adjacent to Frankford Street (Figure 3). Historically, this site was used to store spent lead-acid batteries prior to disposal or recycling. Additionally, attached to one side of Building 2350 (adjacent to Building 2351) is a small, rectangular, 5-ft-wide by 12-ft-long concrete extension that may have been used for weapons discharge testing. Prior to 1995, soil was sampled from the site and determined to be contaminated with metals and petroleum. The metals- and petroleum-contaminated soil was excavated and removed offsite in 1995. Confirmatory samples indicated that the contaminated soil had been removed. Additional soil samples were collected during the Phase I RI in the weapons discharge area, and analyzed for metals and explosives. Arsenic (6.5 mg/kg) was reported above the Industrial Land Use RBC (3.8 mg/kg) but at a concentration similar to the reference arsenic concentration for APG (7.6 mg/kg). Low concentrations of lead (16.2 and 93.4 mg/kg) were detected in some samples; however, concentrations were below industrial based screening criteria (1,000 mg/kg). From the results of the RI, no unacceptable risk to human health (under an industrial land use scenario) was identified; thus, further investigation or remediation for the site beyond the implementation of LUCs prohibiting residential land use (future military family housing, elementary and secondary schools, child care facilities, playgrounds, and non-military residential land use) is not warranted. The site generally consists of gravel pads, impervious surfaces or mowed and disturbed fragments of lawn that do not provide the habitat necessary to support ecological receptors. Therefore, there are no complete ecological exposure pathways and limited potential for ecological risks. Site 10: Building 5039 Battery Shop The Building 5039 Battery Shop is located within the northeastern portion of APG, adjacent to Bel Air Street (Figure 3). Historically, the site was used for temporary storage of lead-acid batteries, and activities associated with vehicle maintenance. Staining was observed during historical site assessments. Surface soil samples collected during the Phase I RI revealed low concentrations of arsenic (4.2 and 5.6 mg/kg) and lead (409 to 442 mg/kg). The arsenic concentrations were reported above the Industrial Land Use RBC (3.8 mg/kg); however, these reported concentrations are comparable to the reference concentration for APG (7.6 mg/kg). The reported lead concentrations were below the Industrial Land Use RBCs (1,000 mg/kg). From the results of the RI, no unacceptable risk to human health (under an industrial land use scenario) was identified; thus, further investigation or remediation for the site beyond the implementation of LUCs prohibiting residential land use (future military family housing, elementary and secondary schools, child care facilities, playgrounds, and non-military residential land use) is not warranted. The site generally consists of gravel parking areas, impervious surfaces, median strips, or mowed and disturbed fragments of lawn that do not provide the

19

habitat necessary to support ecological receptors. Therefore, there are no complete ecological exposure pathways and limited potential for ecological risks. Site 11: Old Burn Trench on Spesutie Island The Old Burn Trench on Spesutie Island is located in the northeastern portion of Spesutie Island, within the Aberdeen Area of APG (Figure 4). Historically, the concrete-lined trench was used for tank testing and burning chemical compounds from 1917 until the late 1950s, when the walls of the trench were demolished and the trench was backfilled with soil and concrete debris. The exact location of the former trench is unknown, but site personnel identified four possible areas for further investigation. A geophysical survey was conducted during the Phase I RI to locate and further define the former trench areas. Three linear geophysical features were identified and could have been potential former trench locations. Phase II RI activities included four test pits to assess the linear geophysical anomalies. Additionally, groundwater and soil samples were collected during the Phase II RI from suspect areas delineated during the geophysical survey. From direct observation during the test pitting, the geophysical anomalies were determined to be subsurface wires. Eight metals (arsenic, beryllium, chromium, iron, lead, magnesium, nickel, and zinc) in the soil samples were reported above the BTAG criteria. However, only arsenic (4.53 to 6.33 mg/kg) was reported above the Industrial Land Use RBC (3.8 mg/kg), and the reported arsenic concentrations are comparable to the reference metals concentrations at APG (7.6 mg/kg). Two filtered metals (iron and manganese) were reported in the groundwater samples above the screening criteria (USEPA Region III tap water RBCs). No MCLs have been established for iron and manganese. USEPA has established National Secondary Drinking Water Standards for iron and manganese, which are non-enforceable guidelines for contaminants that may cause cosmetic effects or aesthetic effects (such as taste or color) in drinking water. The National Secondary Drinking Water Standard for iron is 300 µg/L, and is 50 µg/L for manganese. The maximum reported concentrations for iron (4,870 μg/L) and manganese (3,780 μg/L) exceeded the non-enforceable National Secondary Drinking Water Standards. Additionally, 1,1-dichloroethene (0.76 μg/L) and bis(2-ethylhexyl)phthalate (8.2 μg/L) were reported in groundwater samples. It is likely that the reported concentrations detected above the screening criteria (manganese and iron in ground water) are from a combination of naturally occurring background levels of iron and manganese and non-waste related anthropogenic sources. There is no enforceable MCL for these compounds and these levels do not justify remediation of the ground water at this site. From the results of the RIs, no unacceptable risk to human health (under an industrial land use scenario) or to ecological receptors were identified; thus, further investigation or remediation for the site beyond the implementation of LUCs prohibiting residential land use (future military family housing, elementary and secondary schools, child care facilities, playgrounds, and non-military residential land use) is not warranted.

20

Site 18: Barrels Near Building 510 Building 510 is located in the northeast portion of the restricted area in a warehouse complex along Mulberry Point Road (Figure 4). A large open storage area is located between the railroad sidings and Spesutie Narrows, in an area to the east of Building 510. Numerous tracked vehicles, pallets of materials, lumber, and utility poles are in the storage area. During completion of the Phase I RI, approximately 30-40 barrels were observed in the storage area, intermixed with other metallic debris. The barrels were in poor condition and were of various sizes; the former contents of the barrels are unknown. A geophysical survey was performed and identified several anomalies for further investigation. Soil and groundwater samples were collected from within the storage area during the Phase I RI. Elevated concentrations of arsenic (7.0 to 36 mg/kg) and lead (649 and 9,660 mg/kg) were detected in some of the soil samples. Two unfiltered groundwater samples were collected and submitted for laboratory analysis of the full TCL/TAL parameters, herbicides, and explosives during the Phase I RI. Arsenic (7.6 to 11.9 μg/L, iron (1,040 to 29,700 μg/L) , and manganese (13,400 to 27,700 μg/L) were reported at levels equaling or exceeding the MCLs/RBCs; however, the reported concentrations are likely from naturally occurring subsurface conditions at the site. As part of the Phase II RI, an additional assessment was performed to delineate the extent of the lead-impacted soil for subsequent removal. Approximately 25 tons of lead-/metals-impacted soil (lead concentrations greater than 1,000 mg/kg) and all of the exposed drums were removed from the site. Three confirmatory samples were collected from the bottom of the excavation. Only arsenic in one sample (at a concentration of 4.24 mg/kg) was reported above the industrial soil RBC (3.8 mg/kg). No arsenic was reported in the other two soil samples. However, the reported concentration is not significantly higher than the reference concentration for APG (7.6 mg/kg). Lead concentrations in the confirmatory soil samples ranged from 64.1 to 286 mg/kg, which is lower than the USEPA Interim Lead Screening Level for industrial land use (1,000 mg/kg) but higher than the BTAG screening value of 0.01 mg/kg. Additionally, the post-confirmatory soil sample results were also evaluated as part of the baseline ecological risk assessment. Based on the risk assessment, this area is considered unlikely to pose ecological risks. From the results of the RIs including the soil and drum removal and the baseline ecological risk assessment, no unacceptable risk to human health (under an industrial land use scenario) or to ecological receptors were identified; thus, further investigation or remediation for the site beyond the implementation of LUCs prohibiting residential land use (future military family housing, elementary and secondary schools, child care facilities, playgrounds, and non-military residential land use) is not warranted.

21

Site 19: Sandblast Area Near Building 523 This site is located in the northeastern portion of the restricted area of APG (Figure 4). Sandblasting historically took place on the flat area of the site, behind Buildings 523 and 528. Sandblasting was done to prepare vehicles, guns, and tanks for painting. Sandblasting has ceased at the site, and the site is currently used for vehicle storage. In June 1988, during Phase I of the RFA, five composite surface soil samples were collected from the Sandblast Area and submitted for laboratory analysis of Priority Pollutant List (PPL) metals. Results indicated lead concentrations ranging from 69.5 to 804 mg/kg, with the highest concentrations reported immediately south of Building 523. In February 1990, during Phase II of the RFA, grid sampling was performed to delineate the elevated metals concentrations. Results indicated lead concentrations ranging from 86.4 mg/kg (background) to 2,060 mg/kg, with the highest concentrations reported in the perimeter grid areas. In September and October 1994, 12 additional surface soil samples were collected from the area exhibiting elevated lead concentrations and submitted for laboratory analysis of Toxicity Characteristic Leaching Procedure (TCLP) parameters and lead (URS 2002). Four samples exhibited lead at concentrations above the lead screening criteria of 400 mg/kg. Removal actions were performed in November and December 1994 to remove surface soils exhibiting lead concentrations greater than 400 mg/kg (selected cleanup criteria at the time of the removal). In total, 568 tons of soil was removed from the site. Following completion of the December 1994 removal action, 13 confirmatory samples were collected and submitted for laboratory analysis of the full Contract Laboratory Program (CLP) parameters (TAL metals, TCL VOCs, TCL SVOCs, pesticides/PCBs); in addition, one soil sample was submitted for laboratory analysis of lead. No TCL VOCs, TCL SVOCs, or TCL pesticides/PCBs were reported at concentrations equal to or exceeding the USEPA Region III Industrial Land Use RBCs for soil. Arsenic concentrations were reported to range from 4.2 to 5.9 mg/kg, comparable to the reference concentration for APG. Results of the confirmatory soil sampling performed following the lead-impacted soil removal indicated lead concentrations ranging from 14.1 to 783 mg/kg, and averaging 342.7 mg/kg. In 2001, during completion of the Phase I RI (URS 2002), six surface soil (0 to 3 in.) and two groundwater samples were collected and submitted for laboratory analysis. Groundwater samples were also submitted for laboratory analysis of explosives, alpha/beta, and uranium isotope and radionuclides. From the Phase I RI soil sampling, lead concentrations ranged from 18.5 to 660 mg/kg, which is lower than the USEPA Interim Lead Screening Level for an industrial land use (1,000 mg/kg) but higher than the BTAG value of 0.01 mg/kg. Arsenic in the soil samples was reported to range from 4.2 to 5.9 mg/kg, which is greater than the USEPA Region III industrial RBC of 3.8 mg/kg, and was comparable to the reference concentration for APG. No compounds or analytes were reported in the groundwater samples with concentrations equal to or above the USEPA MCLs and/or USEPA Region III tap water RBCs. The site is also located in an active downrange area, which limits human exposure pathways.

22

In addition, the investigative results were evaluated as part of the baseline ecological risk assessment of the Other Aberdeen Areas (APG 2002). During this assessment, PCBs were identified as a potential concern for ecological receptors near Building 523. The PCB concentrations detected during the Phase I RI (ranging from non-detect to 0.35 mg/kg Aroclor 1260) were below USEPA Region III Industrial Land Use RBCs. Based on the risk assessment, chemicals at the Sandblast Area Near Building 523 do not pose risks to ecological receptors. From the results of the RI , no unacceptable risk to human health (under an industrial land use scenario) or to ecological receptors were identified; thus, further investigation or remediation for the site beyond the implementation of LUCs prohibiting residential land use (future military family housing, elementary and secondary schools, child care facilities, playgrounds, and non-military residential land use) is not warranted. Site 20: Potential Explosives in Groundwater Area This site is located in the north-central portion of the restricted area of APG (Figure 5). The site consists of the following four potential sources of explosives contamination east and west of Michaelsville Road: Former Plate Pile Site near Building 702, the Building 745 and the New Plate Storage Pad Site, the Fragmentation Pit near Building 705B Site, and the Bomb Throwing Device (BTD) Range. The sites were initially investigated in 1993, at which time groundwater sampling was performed. Low concentrations of high melting explosive (HMX) and royal demolition explosive (RDX) were identified west and southeast of the previously mentioned four sites. No sources have been identified and the site is within an active range area. Additional investigation was performed at the site during the Phase I and II RIs. Surface water, sediment, and groundwater samples were collected as part of that investigation. Low concentrations of barium (10.7 μg/L) and lead (4.4 μg/L) were detected in some of the surface water below the USEPA Region III tap water RBC. Low concentrations of 4,4-DDT’ (0.077 mg/kg) and zinc (475 mg/kg) were reported in the sediment samples and were below the USEPA industrial soil RBC. The results of the groundwater sampling (for compounds that were reported with concentrations equal to or greater than the tap water RBCs) from the Phase I and II RIs are shown below:

Analyte Concentration(s) Detected Concentration(s) Detected USEPA Tap Water USEPA (Phase I RI) (Phase II RI) RBC MCL

Heptachlor Not detected to 0.046 μg/L Not detected 0.015 μg/L 0.4 μg/L Iron < 12 μg/L to 11,800 μg/L 18.3 μg/L to 339,000 μg/L 1,100 μg/L Not Published RDX < 0.20 μg/L to 4.12 μg/L Not detected to 3.26 μg/L 0.61 μg/L Not Published Manganese Below screening criteria 11.6 μg/L to 648 μg/L 73 μg/L Not Published Aluminum Below screening criteria 28.8 μg/L to 13100 μg/L 3700 μg/L Not Published Chromium Below screening criteria 0.77 μg/L to 17.9 μg/L 11 μg/L Not Published

23

RDX was only detected in one groundwater monitoring well in the two groundwater sampling events. The absence of detectable concentrations in the surrounding groundwater monitoring wells indicates that the RDX observed at the site is not migrating. From the results of the RIs, no unacceptable risk to human health (under an industrial land use scenario) or to ecological receptors were identified; thus, further investigation or remediation for the site beyond the implementation of LUCs prohibiting residential land use (future military family housing, elementary and secondary schools, child care facilities, playgrounds, and non-military residential land use) is not warranted. Site 21: POL Facility Sand Pit Near Building 5215 This site is located outside the restricted area, in the northeast portion of APG, in a gravel parking lot adjacent to Building 5217 near the intersection of Ravenna Road and Frankford Street (Figure 3). Building 5215 was historically used as a petroleum, oil, and lubricant (POL) storage facility managed by the personnel in Building 5217. Materials used at the facility likely consisted of petroleum products such as motor and gear oils, hydraulic fluids, and lubricants; it is unknown whether solvents were used and stored at the facility. In 1987, a soil removal action, consisting of an approximate 50-square-foot (ft2) area of petroleum-impacted soil, was performed at the site to a depth of 6 to 8 in. However, it is unclear whether confirmatory soil sampling was performed. Additional soil and direct-push groundwater samples were collected from the site during the Phase I RI. No exceedances were detected in soil samples. Elevated concentrations of 11 metals, benzene (2 μg/L), and 1,2-dichloroethane (5 μg/L) were detected in groundwater samples at concentrations above the screening criteria (RBC of 0.36 μg/L for benzene and MCL of 5 μg/L for 1,2-dichloroethane). Due to the elevated concentrations of metals and VOCs in the groundwater samples in the Phase I RI, one groundwater monitoring well was installed at the site during the Phase II RI to assess VOC concentrations and to determine whether the elevated metals concentrations were due to suspended particulates. Groundwater samples were collected from the monitoring well during three separate sampling events (conducted during the Phase II RI in 2001), which resulted in the detection of elevated concentrations of metals in unfiltered groundwater samples. VOCs detected in the groundwater samples were reported below the MCL. The metals were not detected above tap water RBCs or MCLs in the corresponding filtered groundwater samples and the results were attributed to the suspended particulates in the unfiltered sample. Vinyl chloride, dieldrin, and o-nitrotoluene concentrations were reported in some of the groundwater samples below the MCLs. These concentrations were also not consistently detected during the three groundwater sampling events and therefore these non-repeatable low-level concentrations are not indicative of localized groundwater impacts. From the results of the RIs, no unacceptable risk to human health (under an industrial land use scenario) was identified; thus, further investigation or remediation for the site beyond the implementation of LUCs prohibiting residential land use (future military family housing,

24

elementary and secondary schools, child care facilities, playgrounds, and non-military residential land use) is not warranted. The site generally consists of gravel pads, impervious surfaces, median strips, or mowed and disturbed fragments of lawn that do not provide the habitat necessary to support ecological receptors. Therefore, there are no complete ecological exposure pathways and no potential for risks. Site 22: Buildings 309 and 390 Storm Sewer Outfalls The Buildings 309 and 390 storm sewer outfalls are located within and outside of the restricted area, in the north-central portion of APG (Figure 4). Building 309 is located in the restricted area, within the Army Research Laboratory (ARL) compound. Wastewater streams from Building 309, consisting of explosive residues and photographic developing contaminants from laboratory areas, historically discharged into a tributary of Dipper Creek. Similar to Building 309, the Building 390 waste stream was determined to be discharging into the tidal floodplain of Dipper Creek. Although the content of the waste stream was uncertain, contaminants may have included explosive residues and photographic developing contaminants. Currently, the outfalls discharge stormwater and are no longer connected to the buildings. In 1994, APG performed sediment sampling at three locations in Dipper Creek in support of the risk and biological impact assessment (APG 1995). The 1994 samples reported pesticides, polycyclic aromatic hydrocarbons (PAHs), and inorganic chemicals at concentrations above ecological risk screening values in the sediments of Dipper Creek. Most notably, silver was found in every sample at a maximum concentration more than 10 times the Effects Range−Medium (ER–M) screening criterion of 2.2 mg/kg. During the subsequent Phase I and Phase II RIs, additional surface water and sediment samples were collected from each outfall, Dipper Creek, and along the drainage. Bromodichloromethane, chloroform, and several metals (total cyanide, total iron, total manganese, and total vanadium) were reported above the Ambient Water Quality Criteria (AWQC) during the Phase I RI. Several metals (total and dissolved arsenic, total and dissolved iron, total and dissolved manganese) were reported above the screening criteria (USEPA Region III tap water RBCs) during the Phase II RI. The reported arsenic concentrations for the unfiltered groundwater sample (4.59 μg/L) and the filtered groundwater sample (5.03 μg/L) were below the MCL (10 ug/L). No MCLs have been established for iron and manganese. USEPA has established National Secondary Drinking Water Standards for iron and manganese, which are non-enforceable guidelines for contaminants that may cause cosmetic effects or aesthetic effects (such as taste or color) in drinking water. The National Secondary Drinking Water Standard for iron is 300 µg/L, and is 50 µg/L for manganese. The reported iron concentrations (4,710 and 9,700 μg/L) and manganese (1,030 and 1,040 μg/L) exceed the guidelines. Based on the reported source of contamination, which was discharged wastewater with explosive residues and photographic developing contaminants, it is unlikely that the reported manganese and iron concentrations found in the groundwater above the screening criteria is related to wastewater released by the storm sewers. It is more likely that the concentrations are from a combination of naturally occurring background levels of iron and manganese and non-waste

25

related anthropogenic sources of iron and manganese. There is no enforceable MCL for these compounds and these levels do not justify remediation of the ground water at this site. Benzo(a)pyrene (ranging from 0.14 to 2.4 mg/kg) in sediment was reported above the screening criteria (USEPA Region III Industrial Land Use RBCs for soil) during the Phase I RI. Industrial Land Use RBCs for soil were utilized as a screening criteria because there are no sediment RBCs. However, using soil RBCs for sediment concentrations is too conservative. Therefore, it is standard practice in human health risk screening to use 10 times the industrial soil RBC for sediment concentrations; therefore, the reported concentrations are less than the benzo(a)pyrene comparison value of 4.3 mg/kg. Arsenic in sediment was reported above the screening criteria (USEPA Region III Industrial Land Use RBCs for soil) during the Phase II RI. However, the reported concentrations are less than the arsenic comparison value of 38.0 mg/kg. In addition, the reported arsenic concentrations (1.8 to 19.7 mg/kg) are comparable to the reference sediment concentration at APG (0.424 to 18.9 mg/kg) and the reported concentrations are likely attributable to background conditions. In addition, investigative results were evaluated as part of the baseline ecological risk assessment of the OAA (APG 2002). During this assessment, silver and metals were identified as a potential concern for ecological receptors in Dipper Creek. However, toxicity tests showed no significant difference from reference locations. Therefore, no ecological risks were identified. From the results of the RIs and the baseline ecological risk assessment, no unacceptable risk to human health (under an industrial land use scenario) or to ecological receptors was identified; thus, further investigation or remediation for the site beyond the implementation of LUCs prohibiting residential land use (future military family housing, elementary and secondary schools, child care facilities, playgrounds, and non-military residential land use)is not warranted. Site 27: German Ammunition Train This site is located in the central portion of the restricted area of APG, just east of Michaelsville Road (Figure 5). Historically, approximately 200 tons of German ammunition was stored on railroad cars awaiting disposal following World War II. An explosion of approximately 20 tons occurred, scattering the remaining munitions over an estimated 400-acre area. The explosion occurred on the railroad tracks along Michaelsville Road, between Building 710 and the road’s intersection with Rifle Range Road near Building 728. The affected area is on both sides of Michaelsville Road. Currently, the site is located within an active range area controlled and operated by Aberdeen Test Center (ATC). In 2001, during the Phase I RI, an unexploded ordnance (UXO) survey was performed at the site to delineate the extent of UXO. Several areas with high metallic densities were noted within the overall area of the explosion. However, the difference between debris associated with the train explosion and debris associated with other test activities could not be determined. Groundwater samples were also collected during the Phase I and Phase II RIs. Concentrations of two metals (iron and manganese) in filtered groundwater samples were reported above the USEPA Region III tap water RBC. Reported iron concentrations in the filtered groundwater

26

sample ranged from 2,540 to 5,730 μg/L. Reported manganese concentrations ranged from 850 to 1,960 μg/L. No MCLs have been established for iron or manganese. USEPA has established National Secondary Drinking Water Standards for iron and manganese, which are non-enforceable guideline for contaminants that may cause cosmetic effects or aesthetic effects (such as taste or color) in drinking water. The National Secondary Drinking Water Standard for iron is 300 µg/L, and is 50 µg/L for manganese. The reported concentrations exceed the National Secondary Drinking Water Standards for iron and manganese. However, the mean APG background reference groundwater concentration for iron is 3,694 µg/L, and for manganese is 5,454 µg/L. Therefore, the reported iron concentrations are comparable to the reference concentration while the manganese concentrations are lower than the reference concentration. It does not appear that groundwater has been impacted by former site activities. Although UXO is present at the site, the site is currently within an active range area (which is not regulated under CERCLA) and limits human exposure pathways. From the results of the RIs, no unacceptable risk to human health (under an industrial land use scenario) or to ecological receptors were identified; thus, further investigation or remediation for the site beyond the implementation of LUCs prohibiting residential land use (future military family housing, elementary and secondary schools, child care facilities, playgrounds, and non-military residential land use)is not warranted. Site 28c: Building 2458 UST Site Building 2458 is located in the northwest portion of the unrestricted area of APG, near the intersection of Maryland Boulevard and Proving Ground Road (Figure 3). Prior to its removal, a fuel oil UST was located adjacent to the northwest side of Building 2458. VOCs related to solvents (primarily TCE) had been detected as part of regular monitoring of the UST well. During the Phase I RI, groundwater samples were collected from the former location of the UST. TCE (14 μg/L) was reported in one groundwater sample collected adjacent to the area where the former UST was located. The reported concentration of TCE was above the MCL (5 µg/L). Additional groundwater samples were collected during the Phase II RI to further assess the reported TCE concentration. TCE was detected in the shallow groundwater sample (1.86 μg/L) and not in the deeper groundwater samples. The reported TCE concentration was below the MCL. Results indicate that low concentrations were localized within the vicinity of the former UST location and did not extend into the deeper aquifer. From the results of the RIs, no unacceptable risk to human health (under an industrial land use scenario) or ecological receptors were identified; thus, further investigation or remediation for the site beyond the implementation of LUCs prohibiting residential land use (future military family housing, elementary and secondary schools, child care facilities, playgrounds, and non-military residential land use)is not warranted. The site consists primarily of paved parking and median areas. There is no potential for ecological risks as there is no significant surface soil contamination. Therefore, there are no complete exposure pathways for ecological receptors.

27

Site 28d: Building 3329 UST Site Building 3329 is located in the northwest portion of the unrestricted area of APG, near the intersection of Maryland Boulevard and Proving Ground Road (Figure 3). Building 3329 was formerly used as a gasoline service station at APG. In 1991, four 10,000-gallon USTs that were used to store gasoline were removed from the site as part of tank closures. One 550-gallon fuel-oil-containing AST and one 550-gallon waste-oil-containing AST were also removed from the site later that year. At the time of removal, the tanks were reported to have been on the site for 26 years. VOCs related to solvents (primarily tetrachloroethene [PCE]) were detected in two monitoring wells at the site. During the Phase I RI, PCE was reported in two of the four shallow groundwater sample locations with concentrations of 4 and 10 μg/L. The MCL for PCE is 5 μg/L. Based on the PCE detections, additional groundwater samples were collected during the Phase II RI. Three groundwater samples were collected from various depths with PCE detected in the 70 to 74 ft bgs depth interval (1.17 μg/L) and the 51 to 55 ft bgs depth interval (0.6 µg/L); both concentrations were below the MCL. Results indicate that low concentrations were localized within the vicinity of the former UST location and did not extend into the deeper aquifer. From the results of the RIs, no unacceptable risk to human health (under an industrial land use scenario) or ecological receptors were identified; thus, further investigation or remediation for the site beyond the implementation of LUCs prohibiting residential land use (future military family housing, elementary and secondary schools, child care facilities, playgrounds, and non-military residential land use)is not warranted. The site consists primarily of paved parking and median areas. There is no potential for ecological risks as there is no significant surface soil contamination. Therefore, there are no complete exposure pathways for ecological receptors. Site 28e: Building 3505 UST Site Building 3505 is located in the northwest portion of the unrestricted area of APG near the intersection of Maryland Boulevard and Proving Ground Road (Figure 3). Prior to its removal, a fuel-oil-containing UST was located adjacent to the southwest side of Building 3505. During the Phase I RI, four direct-push groundwater samples were collected and submitted for laboratory analysis of TCL VOCs and SVOCs. TCE was reported above the USEPA Tap Water RBC (1.6 μg/L) in three groundwater samples (2 to 24 μg/L). During the Phase II RI, groundwater samples were collected at 1 rotosonic boring location, 21 direct-push locations , one existing UST monitoring well, and one additional monitoring well installed during the Phase II RI. Four groundwater samples were collected from the rotosonic boring location and its associated direct-push sampling location. TCE was reported in the rotosonic boring groundwater samples from 43 to 47-ft bgs (86 μg/L) and 65 to 69-ft bgs (58 μg/L). No TCE was reported in the deep rotosonic groundwater sample from 117 to 112-ft bgs or the associated geoprobe sample collected from the same depth interval.

28

Thirty-eight (38) groundwater samples were collected from the 21 direct-push sampling locations at various depths and submitted for TCL VOC analysis. PCE was reported above the Tap Water RBC (0.63 μg/L) in 23 samples and above the MCL (5 μg/L) in 3 samples. Reported PCE concentrations ranged from 0.50 μg/L to 6.61 μg/L. TCE was reported above the Tap Water RBC (0.026 μg/L) in 11 samples and above or equal to the MCL (5 μg/L) in 6 samples. Reported TCE concentration ranged from 0.64 to 184 μg/L. Groundwater samples were collected during two sampling events at the two site monitoring wells in August and November 2001. TCE was reported above the Tap Water RBC and the MCL in both groundwater samples during each sampling event as shown below:

Event UST Well G28E-MW-1 Location Aug 2001 Nov 2001 Aug 2001 Nov 2001

TCE (μg/L) 76.2 126 5.31 7.68 TCE and PCE concentrations were detected that exceed MCLs; however, based on the results of the Phase II RI, the detections are sporadic and localized in the vicinity of the former UST. Based on review of the site data, the USEPA Regional Project Manager and Hydrogeologist concluded that the concentrations and distribution of PCE and TCE were not representative of a contaminant plume. From the results of the RIs, no unacceptable risk to human health (under an industrial land use scenario) or ecological receptors were identified; thus, further investigation or remediation for the site beyond the implementation of LUCs prohibiting residential land use (future military family housing, elementary and secondary schools, child care facilities, playgrounds, and non-military residential land use)is not warranted. The site consists primarily of paved and gravel parking areas. There is limited ecological habitat and potential for ecological risks as there is no significant surface soil contamination. Therefore, there are no complete exposure pathways for ecological receptors. 2.5.3 8 NFA SITES The 8 NFA Sites are shown on Figures 4, 5, and 6. Site 3: Churchville Test Course Dump The Churchville Test Course Dump site is located approximately 8 miles northwest of the Aberdeen Area of APG (Figure 6). This site was initially investigated as part of the Installation Assessment (IA) Report (APG 1981) where it was referenced as the Landfill at the Churchville Test Course. At that time, the location was not specified and no information was provided regarding investigations or the history of the dump. During the subsequent RFA investigation completed in 1990 (APG 1990), facility personnel indicated that the old landfill was located in the middle of a natural drainage ditch, approximately 30 ft wide by 200 ft long. Interviews with facility personnel, conducted at the time of the RFA, indicated that a cleanup (using manual labor and heavy equipment) occurred at the landfill in the 1980s. Following the cleanup, the area was lined with sediment-trap cloth, followed by 3- to 4-ft granite boulders and riprap.

29

In 1997, the boundary of the dump was established by a review of aerial photographs and a geophysical survey by the Waterways Experiment Station (WES). The results indicated that the dump encompassed an approximate 35-ft-wide by 50-ft-long area. In 2001, during completion of the Phase I RI (URS 2002), four surface soil, four surface water, and four sediment samples were collected and submitted for laboratory analysis. Groundwater was not encountered during drilling activities (drilling refusal on saprolite/bedrock before groundwater along the perimeter of the presumed dump area) and was therefore not sampled. During completion of the Phase II RI, one boring was installed using rotosonic techniques into bedrock in order to collect two groundwater samples. No analytes were detected at or exceeding sediment screening criteria for the sediment samples collected (USEPA Region III Industrial Land Use RBCs). Arsenic was reported in one soil sample at a concentration (4.7 mg/kg) exceeding the soil screening criterion of 3.8 mg/kg. Four TAL metals (barium, cobalt, iron, and manganese) were reported in surface water samples at concentrations that equaled or exceeded the surface water criteria (AWQC). Five TAL metals (aluminum, chromium, iron, manganese, and vanadium) were detected at concentrations exceeding screening criteria (USEPA Region III RBCs for tap water). Total chromium (1.23 and 72 µg/L), the only metal detected in the unfiltered groundwater samples above the USEPA Region III RBC, was reported below the MCL (100 µg/L). No total chromium was reported in the filtered groundwater samples. With the exception of manganese, the elevated metals concentrations were only associated with unfiltered groundwater samples and are likely attributed to interference of suspended solids within the sample matrix. While manganese was reported above the USEPA Region III RBC, no MCL currently is promulgated for manganese. A National Secondary Drinking Water Standard, a non-enforceable guideline for contaminants that may cause cosmetic effects or aesthetic effects (such as taste or color) in drinking water, has been established for manganese (0.05 mg/L). Subsequent to the completion of the Phase I and Phase II RIs, investigative results were evaluated as part of the baseline ecological risk assessment of the OAA (APG 2002). During this assessment, PCBs were identified as the only potential chemicals of concern for ecological receptors at the Churchville Test Course Dump. Based on the Step 4 Ecological Risk Assessment Work Plan, samples were collected in 2001 to confirm the single PCB detection in 1998; PCBs could not be re-detected, and were therefore determined not to pose ecological risks. With respect to metals concentrations in surface water or surface soil above screening criteria, these metals occur widely in the earth’s crust as natural minerals and are, therefore, commonly identified in soil, sediment, surface water, and groundwater. APG has compiled data regarding anticipated concentrations of various metals in soil, groundwater, sediment, and surface water. A listing of these concentrations as compared to the concentrations identified at the site is illustrated below. As shown, the concentrations of arsenic, barium, cobalt, iron, and manganese are comparable to the reference metals concentrations for APG. Therefore, the occurrences of these metals in the above-referenced media samples are likely attributable to background conditions and not a result of site-related activities. Therefore, no further action is warranted for this site.

30

Analyte Media Concentration(s) Detected Reference Range

Arsenic Soil 4.7 mg/kg 1.04 – 5.29 mg/kg Barium Surface Water 31.7 – 50 mg/L 9.6 – 49.2 mg/L* Cobalt Surface Water < 3.0 – 7.7 mg/L <5 – 20.7 mg/L Iron Surface Water 325 – 5,590 mg/L 265 – 9,020 mg/L Manganese Surface Water 106 – 1,650 mg/L 41.7 – 743 mg/L Groundwater 252 – 471 mg/L 3.2 – 866 mg/L

* Reference concentrations for analytes detected in spring surface water at freshwater creeks. Site 13: Chemical Dump Ponds on Spesutie Island This site is located in the northeastern portion of Spesutie Island, west of Spesutie Island Road (Figure 4). The site consists of two shallow pond areas identified as the North Ponds and the South Ponds. Each set of ponds consists of three long, narrow, ponds (total of six ponds) that were excavated using explosives in 1965. The North Ponds were created for the purpose of excess chemical disposal. The types and quantities of materials disposed in the ponds are not known, nor are the timing and duration of disposal. The South Ponds were created as a duck habitat. Sediment, surface water, and groundwater samples were collected in and around the ponds during the Phase I RI. Concentrations of metals (barium, cadmium, cobalt, iron, lead, manganese, and zinc) and one pesticide (heptachlor) were detected in some of the surface water samples. Heptachlor (0.059 μg/L) was detected in one surface water sample above the AWQC (0.0069 µg/L) but below the MCL (0.4 μg/L). The concentrations of barium, cadmium, and lead were reported below the MCLs. Endosulfan I (0.0042 mg/kg) and arsenic (ranging from 4.2 to 10.5 mg/kg) were reported in the sediment samples equal to or exceeding the USEPA Sediment Quality Benchmark criteria (0.0029 mg/kg and 8.2 mg/kg, respectively). As a human health risk evaluation, the Endosulfan I and arsenic concentrations were compared to the standard practice of 10 times the industrial land use RBC. The reported concentrations are lower than the standard practice sediment comparison concentrations of 6,100 mg/kg for Endosulfan I and 38 mg/kg for arsenic. Therefore, the reported concentrations were below the human health risk screening criteria. Bis(2-ethylhexyl)phthalate (66 μg/L) and manganese (858 to 3,490 μg/L) were detected in groundwater samples collected with concentrations greater than the groundwater comparison criteria [6 μg/L (MCL) and 730 μg/L (RBC), respectively]. It should be noted that bis (2-ethylhexyl)phthalate was reported in only one of 14 groundwater samples collected. A National Secondary Drinking Water Standard, a non-enforceable guideline for contaminants that may cause cosmetic effects or aesthetic effects (such as taste or color) in drinking water, has been established for manganese (500 µg/L). It was observed that the immediate area was located within a tidally influenced marsh and, due to

31

tidal effects, groundwater has little effect on surface water quality in the ponds. Therefore, based on the sampling results, minimal environmental impacts are associated with the dump pond locations. Therefore, the occurrences of the contaminants in the above-referenced media samples are likely attributable to surface water influences from flooding and not a result of site-related activities. Therefore, no further action is warranted for this site. Site 14: Former Burning Area Near Building 1171 The Former Burning Area near Building 1171 is located in the eastern portion of Spesutie Island Road on APG (Figure 4). This site was historically used for the open burning of high explosives (HE), from about 1948 to 1960. On average, approximately 100 pounds of HE (primarily trinitrotoluene [TNT]) were burned per week during that time. Former burning sites were also noted to have existed adjacent to Building 1171. Burning operations ceased following construction completion of Building 1171 in 1960. The exact locations of the burning areas are unknown; however, during completion of the Phase I RI, rectangular features considered to be potential former burning pads were identified via visual observations and aerial photographs. During the RFA in 1990 and during the Phase I RI, a total of 27 surface soil samples were collected in the areas proximate to the former burn pads and in various areas throughout the site and were analyzed for metals, VOCs, SVOCs, explosives, PAHs, and pesticides. No analytes were detected during the RFA or the Phase I RI investigation equal to or above the USEPA Residential Land Use RBCs. Therefore, no further action is warranted for this site. Site 15: Metal Barricade Near Building 1122 The Metal Barricade near the Building 1122 Site is located on the north end of Spesutie Island, approximately 350 ft south of Building 1122 in a mowed, open area, and is in close proximity to a tidal marsh tributary that discharges into Back Creek (Figure 4). The metal barricade consists of an above-grade metal box (1-in. steel plating, 8 ft wide by 10 ft long) that is open on one side. The open side faced the salt marsh. Historically, it was reported that the metal barricade was used for the burning of ignitable and combustible materials, laboratory residues, and wastes, including residual methylene chloride and carbon tetrachloride. No documents or records indicating the quantity or quality of the materials burned in the barricade were identified during the RFA or the Phase I RI. A composite soil sample was collected immediately south of the open face of the container during the RFA and was submitted for laboratory analysis of explosives and ammonium picrate. No detectable concentrations of explosives were reported in the composite soil sample. Soil and groundwater samples were collected during the Phase I RI proximate to the barricade. Wipe samples were also collected from the interior walls and floor of the barricade. No concentrations of explosives or SVOCs were reported in the soil or groundwater samples at concentrations equal to or above the USEPA Region III Residential Land Use RBCs.

32

Four SVOCs and one explosive were reported in the interior wipe samples as shown below:

Analyte Concentration(s) Detected (μg/ft2) Screening Criteria

Diethylphthalate 32 to 86 Not Applicable Pentachlorophenol < 830 to 20 Not Applicable Di-n-butylphthalate < 330 to 20 Not Applicable Butybenzylphthate 24 to 37 Not Applicable 2,4,6-trinitrotoluene < 0.27 to 4.47 Not Applicable While there were detections of SVOCs and an explosive in the wipe samples, the lack of evidence of a significant release to soil or groundwater indicates that a majority of the spent chemicals volatilized during the waste burning events and had not impacted the subsurface. Therefore, no further action is warranted for this site. Site 24: White Phosphorous Munitions Land Burial Area This site is located in the northeast portion of the restricted area of APG near the mouth of Mosquito Creek (Figure 4). Historically, the site consisted of two suspect areas of white phosphorous dumping or burial, designated as the White Phosphorous Underwater Munitions Burial Area (WPUMBA) and the White Phosphorous Land Burial Area (WPLBA). The WPUMBA site location was determined to be in the Chesapeake Bay, within the vicinity of Black Point. The site reportedly consisted of United States, British, and French land mines, grenades, artillery shells, and bulk phosphorous. However, several investigations were performed in the area and the site was never found. A ROD was issued in 1991, declaring a no action decision, that no effective remedial action was possible at the site. Historical references also suggested the possibility of a second burial site, the WPLBA, located in a tidal marsh near Black Point. Reportedly, munitions and white phosphorous were buried in the waterfront region near Black Point, possibly within a 4-ton munitions barge.

As a result of these initial findings, a geophysical survey was conducted within the potential burial areas during the Phase I RI to locate large potential munition burial areas. The results of the geophysical survey indicated that within the location of the WPUMBA, anomalies of the appropriate size were not identified, therefore discounting it as a burial location of the white phosphorous. Further, the geophysical survey identified a large metallic object, possibly a barge, within the WPLBA. However, upon further investigation, it was determined that the anomaly was not a barge, but instead clusters of ordnance items related to a prior test firing range (i.e., projectile fragments or UXO). Since the geophysical survey did not locate munitions, no environmental sampling was performed. No evidence of hazardous-waste-related contamination or a munitions burial area has been observed or noted at this site. In addition, this site is located in an active range area, which is not regulated under CERCLA. Therefore, no further action is warranted for this site.

33

Site 28a: Building 436 UST Site This site is located at Building 436 in the northeast portion of the restricted area of APG (Figure 4). Building 436 is located off of Mulberry Point Road and serves as the Automotive Test Facility for the Automotive Test Division, Engineering Directorate of the Aberdeen Test Center. An 8,000-gallon UST, located north of Building 436, was formerly used to store No. 2 fuel oil until it was removed in January 1995. During closure activities, leakage was noted coming from the pipe that connected to the manway of the UST. Soil and groundwater samples were collected, which revealed elevated concentrations of benzene, toluene, ethylbenzene, and xylene (BTEX) and total petroleum hydrocarbons (TPH). Additionally, 1,1,1-trichloroethane (1,1,1-TCA) was reported in two groundwater sample locations with concentrations of 10 to 20 μg/L, which is lower than the MCL of 200 μg/L. Six additional groundwater samples, from two depths at three sampling locations, were collected during the Phase I RI. The VOC 1,1-dichloroethene (1,1-DCE) was reported in each of the shallow groundwater samples at concentrations that ranged from 0.6 to 4 μg/L, below the MCL. No 1,1-DCE concentrations were reported in the deeper groundwater samples. Petroleum contamination in soil and groundwater from petroleum storage tanks is not regulated by CERLCA and will be addressed by the MDE Oil Control Program. Based on the results of the RI, minimal hazardous compound concentrations were associated with the former UST. Therefore, no further CERCLA action is warranted for this site. Site 28b: Building 456 AST Site This site is located near Building 456, in the northeast portion of the restricted area of APG (Figure 4). The site is situated in a flat area containing a dirt-covered test track, a bulk fuel loader, a vacuum chamber, and scrap metal storage. Historically, the site consisted of a former 450,000-gallon, cylindrical AST, two abandoned AST berm areas, several utilities, and a bulk fuel loader. The former AST was reported to contain No. 2 diesel fuel until it was closed in July 1995, after 23 years of service. The two abandoned berm areas previously housed two single-wall, 2,000-gallon ASTs that were used to store gasoline and solvents, until their removal in early 1996. Due to inadequate documentation, the types of solvents stored in the former AST could not be determined. Soil and groundwater samples were collected during the UST/AST removals and revealed the presence of toluene, ethylbenzene, and xylene in shallow soil (0-2 ft bgs), and BTEX in shallow groundwater (13 to 16 ft bgs). Estimated concentrations of unidentified VOCs believed to be associated with solvents were reported by the field laboratory for several soil and groundwater samples. Due to the UST removals sampling results, twenty groundwater samples from 10 sampling locations were collected during the Phase I RI for laboratory analysis of VOCs and SVOCs. One VOC (chloroform at a concentration of 0.6 μg/L in two samples) and one SVOC [bis(2 ethylhexyl)phthalate at a concentration of 5 μg/L in one sample] were reported at concentrations equal to or exceeding the USEPA Region III tap water RBCs. Bis(2-ethylhexyl)phthalate is a

34

common laboratory contaminant and was not site related. In addition, the reported concentration was below the USEPA MCL. No MCL has been established for chloroform. However, chloroform is a trihalomethane, which is a water chlorination by-product. USEPA has established an MCL for total trihalomethanes (including chloroform) of 80 μg/L. The reported concentrations of chloroform (0.6 μg/L) are significantly less than the MCL for total trihalomethanes. Petroleum contamination in soil and groundwater from petroleum storage tanks is not regulated by CERLCA and will be addressed by the MDE Oil Control Program. Based on the results of the RI, minimal hazardous compound concentrations were associated with the former UST. Therefore, no further CERCLA action is warranted for this site. Site 31: Poverty Island Potential Mine Burial Site This site is located in the west-central portion of the restricted area of APG (Figure 5). Historically, this site was used to test fragmentation patterns of exploding munitions, static tests, and mine tests. In the 1940s, red phosphorous tracer testing was also performed on the site. In the early 1990s, during new construction activities at the site, two mines were unearthed. Initial communications with facility personnel were misunderstood to indicate a potential mine burial pit; however, only two mines were found and no pit was uncovered or suspected. Two groundwater samples were collected during the Phase I RI. Gross alpha (ranging from 1.43 to 16.1 picoCuries per liter [pCi/L]) and heptachlor (< 0.053 to 0.019 μg/L) were reported in groundwater above the USEPA MCLs and/or the USEPA Region III RBCs for tap water. Specifically, heptachlor was reported above the USEPA Region III RBCs for tap water (0.015 μg/L) but below the USEPA MCL (0.4 μg/L), and gross alpha was reported only slightly above the USEPA MCL (15 pCi/L). However, the elevated concentrations were attributed to suspended solids in the samples and were not representative of groundwater quality. No evidence of hazardous-waste-related contamination has been observed or noted at this site. In addition, this site is located in an active range area, which is not regulated under CERCLA. Based on the results of the Phase I RI, no further action is warranted for this site. 2.6 CURRENT AND POTENTIAL FUTURE SITE AND RESOURCE USES Control of the two former small arms range sites and the 23 sites is expected to remain under military authority with continued land use for military training, operational range, and industrial activities for the foreseeable future; therefore, future residential development is highly unlikely for these sites. There are currently no drinking water wells at the Pistol Range, Known Distance Range, or any of the 23 sites, and the groundwater is not in use. Generally, metals were reported in filtered and unfiltered groundwater samples (arsenic, iron, manganese, thallium) with concentrations greater than the RBCs but below the MCLs. Based on groundwater sampling and the SPLP analyses, the lead in the berms is not a significant risk to groundwater.

35

The current land use surrounding the AA generally consists of residential communities, light industrial areas, and agricultural areas; these land uses are anticipated to remain the same in the future. The estuaries and creeks around the Pistol Range, Known Distance Range, and 23 Sites are an important natural resource and are used for public recreation including boating, fishing, and swimming; however, a restriction on these activities is imposed directly around military property, which extends offshore approximately 1 mile into the Chesapeake Bay. The water bodies, marshes, and upland areas (particularly areas of the AA where development has not occurred) are also an important habitat for waterfowl, fish, and other wildlife species. 2.7 SUMMARY OF SITE RISKS The Baseline Risk Assessment (BRA) estimates what risk the site poses if no action is taken. It provides the basis for taking action, if necessary, and identifies the contaminants and exposure pathways that need to be addressed by the remedial action. Based on previous investigations performed at the 15 LUC Sites, results showed that these sites did not warrant further investigation or risk assessment, since there were no unacceptable risks identified for human health under an industrial land-use scenario, or for ecological receptors. Based on previous investigations performed at the 8 NFA Sites, results showed that these sites did not warrant further investigation or risk assessment, since there were no unacceptable risks identified for human health under an unrestricted land-use scenario, or for ecological receptors. Therefore, this section of the ROD only summarizes the results of the BRA for the two former small arms range sites (Pistol Range and Known Distance Range). 2.7.1 HUMAN HEALTH RISK ASSESSMENT The purpose of a human health risk assessment is to determine whether exposure to site-related contaminants would likely adversely affect human health. The focus of the human health risk assessment is on the potential human health effects that could occur under current or potential future use scenarios in the event that contamination is not remediated. The risk is expressed as lifetime excess cancer risk (LECR) for carcinogens; as hazard quotient (HQ) for non-carcinogens; and as a probability of exceeding acceptable blood lead levels for lead risks. For example, an LECR of 1×10-6 represents the probability of one additional cancer in a population of one million exposed. The cancer risk of 1×10-4 to 1×10-6 is the acceptable risk range within which risk may be managed. An HQ is the ratio of anticipated exposure of an individual to the reference dose, the dose at which no adverse effects are expected to occur. If this ratio is less than or equal to 1.0, then no adverse non-cancer effects are expected to occur. A hazard index (HI) is the sum of the hazard quotients for all site contaminants and/or routes of exposure. An HI above 1.0 presents a likelihood of non-carcinogenic health effects in exposed populations. For lead risks, exposure models are used to estimate blood lead levels; levels below the USEPA acceptable blood-lead threshold of 10 micrograms per deciliter (μg/dL) are considered not to pose risks.

36

2.7.1.1 Identification of Contaminants of Concern The identification of contaminants of concern for each site was conducted in several steps. First, maximum concentrations of contaminants found were compared to USEPA Region III Risk-Based Criteria or other approved screening levels. Chemicals exceeding or lacking these criteria were identified as contaminants of potential concern (COPCs). These contaminants were then evaluated using exposure models and dose-based criteria to identify chemicals that may pose risks to receptors. Maximum or 95% Upper Confidence Limit on the Mean (UCLM) values were used as the exposure point concentrations in these models based on the statistical distribution of contaminant concentrations. This process resulted in identification of COCs for further evaluation in the Feasibility Study. Human health-based COCs were identified for surface media at the sites. COCs for the Pistol Range and Known Distance Range surface media, their mean, maximum, and exposure point concentrations, and their frequency of detection are presented in Tables 2 and 3, respectively. 2.7.1.2 Exposure Assessment The Known Distance Range is located in a restricted access area where current installation restrictions prevent residential land use. From an assessment of the groundwater samples collected during the RIs, groundwater quality is not significantly different from the reference groundwater quality at APG. In addition, there are no drinking water wells (i.e., public water is provided) at the sites downrange, and installation of such wells at this site is highly unlikely. Therefore, the assessment for the Known Distance Range examined construction worker, adolescent trespasser, and industrial/military/commercial worker exposure scenarios since these sites demonstrate current and reasonably anticipated future industrial/military land use. Due to the restricted range location of these sites, residential scenarios were not considered in the assessment of these sites, but a residential evaluation was performed and results provided for informational purposes only (EA 2005b). (Potential unacceptable residential risks were determined for each site in the residential scenario.) For this downrange site, industrial/military commercial scenarios were considered the reasonable worst-case scenarios and used as the basis for remedial decisions. The Pistol Range is located in the Aberdeen cantonment area (area of installation consisting of military housing, offices and support buildings) of APG. Based on an assessment of the groundwater samples collected during the RIs, no contaminants were reported with concentrations greater than the USEPA Region III tap water RBCs or the MCLs. Site use is currently industrial/commercial; therefore, the assessment for the Pistol Range examined construction worker, adolescent trespasser, and industrial/military/commercial worker exposure scenarios since these sites demonstrate current and reasonably anticipated future industrial/military land use. Because the Pistol Range is located in the cantonment area, the risk assessment also evaluated potential for risks to hypothetical future adult and child residents to determine whether it is cost effective to seek to obtain remedial objectives required for unrestricted use. The risk assessment considered specific exposure pathways for each receptor. Pathways were similar for both sites. For trespassers, exposures to contaminants in surface soil, sediment, and

37

surface water were considered complete via dermal contact, incidental ingestion, and inhalation. For commercial workers, exposures to contaminants in surface and subsurface soil, sediment, and surface water were considered complete via dermal contact, incidental ingestion, and inhalation. For hypothetical residents, exposures to contaminants in surface and subsurface soil, sediment, and surface water were considered complete via dermal contact, incidental ingestion, and inhalation. For construction workers, exposures to contaminants in surface and subsurface soil were considered complete via dermal contact, incidental ingestion, and inhalation. Exposure estimates were derived using exposure assumptions for USEPA guidance, or from other sources with USEPA approval. Exposure parameters and models are presented in detail in the approach document for these sites (EA 2005b). 2.7.1.3 Toxicity Assessment A human toxicity assessment was performed to evaluate whether exposure to specific contaminants may cause adverse effects, and to identify specific numeric criteria that could be used to assess the impacts of such exposures. For non-cancer endpoints, contaminant-specific reference doses (RfDs) were compiled from the Integrated Risk Information System (IRIS), which provides toxicity potency concentrations. Where these were unavailable, toxicity values from the Health Effects Assessment Summary Tables (HEAST) were used as a second source. If a value was not available for one route of exposure, values for alternate routes were evaluated for technical applicability and used where appropriate; for example, some oral RfDs were modified for use as dermal RfDs using adjustment factors. Chronic RfDs were used to assess long-term exposures of 7 years to a lifetime; subchronic RfDs were used to assess exposures of less than 7 years. For lead, the toxicity assessment identified the established blood-lead threshold value of 10 μg/lead/dL for comparison to model results. For carcinogenic endpoints, cancer slope factors were derived from IRIS, HEAST, or other sources as approved. These slope factors relate cumulative exposures to the probability of developing cancer. In some cases, oral RfDs were modified for use as dermal RfDs using adjustment factors. 2.7.1.4 Risk Characterization The following sections discuss the risk characterization results for each of the two former small arms range sites. Site 30a: Pistol Range At Site 30a, surface soil was identified as the only media of concern. Receptors evaluated as part of the HHRA for Site 30a included resident adult and child, adolescent trespasser, construction worker, and commercial worker. Non-carcinogenic risks (HQ greater than 1) from antimony and arsenic in the Pistol Range surface soil were identified for child residents and construction workers. Carcinogenic risks were identified for resident adults, commercial workers, and resident children from arsenic in the site surface soil. Blood lead level modeling for the site

38

indicated unacceptable lead concentrations for residential receptors, but not for construction workers. Table 2 provides a summary of risk assessment results for these COCs.

Table 2: Risk Summary for Primary COCs Contributing to Cancer and Non-Cancer

Hazards for the Pistol Range

Contaminant Concentrations (mg/kg)

Total Carcinogenic Risk

Total Non-Carcinogenic Risk

Contaminants of Concern

Frequency of Detection

Mean

Maximum

EPC Cancer Slope Factor

Slope Factor Source

(Description)

Total Risk Across

Exposure Routes

Reference

Dose (mg/kg-bw/day)

Source (Target Organ)

Total HQ/ Blood Lead

Across Exposure

Routes Future Construction Worker

Antimony 28/41 96 3180 250 NA NA NA 4x10-4 Blood 2.1

Arsenic 41/41 38.3 1150 92.5 1.5 IRIS, 2004 (A) 7.2 x 10-6 3x10-4 Skin 1.1

Future Hypothetical Resident (Adult and Child) Antimony

(child only) 28/41 96 3180 250 NA NA NA 4x10-4 Blood 5.8

Arsenic 41/41 38.3 1150 92.5 1.5 IRIS, 2004 (A) 1.2 x 10-4 3x10-4 Skin 3.2

Lead 41/41 455 1490 455 NA NA NA NA Blood Exceeds threshold

Site 30b: Known Distance Range At the Known Distance Range, there are no concerns for carcinogenic risks for potential receptors (i.e., total carcinogenic risks from contaminants of potential concern in surface media were below 10-6). Additionally, non-carcinogenic risks are not of concern for potential receptors (i.e., HQs for contaminants of potential concern presenting non-carcinogenic risks were less than 1). However, modeled blood lead levels were calculated as unacceptable for trespassers and workers in all media. Table 3 provides a summary of risk assessment results for lead.

Table 3: Risk Summary for Primary COCs Contributing to Cancer and Non-Cancer Hazards for the Known Distance Range

Contaminant Concentrations

(mg/kg)

Total Carcinogenic Risk

Total Non-Carcinogenic Risk

Contaminants of Concern

Frequency of

Detection

Mean

Max

EPC Cancer Slope Factor

Slope Factor Source

(Description)

Total Risk

Across Exposure

Routes

Reference

Dose (mg/kg-bw/day)

Source (Target Organ)

Blood Lead Levels Across

Exposure Routes

Current Trespassers and Commercial Workers (Surface Soil)

Lead 45/45 4,830 87,100 4,830 NA NA NA NA Blood Exceeds threshold

Future Trespassers, Construction and Commercial Workers (Total Soil)

Lead 45/45 3,840 87,100 3840 NA NA NA NA Blood Exceeds threshold

Uncertainties There are a number of uncertainties inherent to human health risk assessment methodology. In many cases, the risk assessment uses assumptions that are conservatively protective, such as ingestion rates or exposure durations. These assumptions are likely to overestimate risks, and may result in risk estimates finding a greater likelihood of effects than actually present.

39

2.7.2 ECOLOGICAL RISK ASSESSMENT An ecological risk assessment was conducted for each site according to USEPA guidance. A conceptual model was developed identifying exposure pathways by which receptors might be exposed to contaminants. Based on this model, concentrations of source-related contaminants in environmental media were screened against conservative screening values provided by USEPA BTAG Region III. Screening results were used with information concerning exposure, toxicity, fate, and transport to conduct a baseline problem formulation and create a BERA site model. Based on this model, additional sampling was conducted and site-specific analyses and bioassays were performed to further investigate site-specific bioavailability, toxicity, and bioaccumulation. This information was used in food web models to derive estimates of wildlife exposures, which were then compared to no observed adverse effects and lowest observed adverse effects benchmarks. Toxicity test data was used to directly evaluate risks to lower trophic level receptors. These results were used as part of a weight of evidence to prepare a risk characterization identifying specific COCs for each receptor. The full weight of evidence is presented in the final ecological risk assessment (EA 2005c). 2.7.2.1 Identification of Contaminants of Concern COCs were identified based on the results of the weight of evidence presented in the risk characterization. A variety of exposure point concentrations and scenarios were evaluated as part of this approach, including site maxima and site mean. Models and comparisons included evaluation of whole media concentrations, estimated bioavailable concentrations of metals, and concentrations in plant, worm, and/or fish tissue from bioassays or field collected specimens. Table 4 presents the final list of COCs as developed in the ecological risk assessments (EA 2005c). 2.7.2.2 Exposure Assessment The BERA conceptual model for the Pistol Range and Known Distance Range identified receptors and assessment endpoints specific to each site. The Pistol Range is characterized as solely terrestrial habitat; assessment endpoints for this site included protection of survival, growth, and reproduction of terrestrial plants, soil invertebrates, herbivorous mammals, vermivorous mammals and birds, and predatory mammals and birds. Protection of amphibians and reptiles was included as an assessment endpoint, although the lack of data for these receptors prohibited quantitative evaluation. The Known Distance Range is characterized as containing both terrestrial habitat and limited ephemeral aquatic habitat in drainage ditches and flooded man-made structures; assessment endpoints for this site included protection of survival, growth, and reproduction of terrestrial plants, soil invertebrates, herbivorous mammals, vermivorous mammals and birds, predatory mammals and birds, amphibians and reptiles, aquatic and benthic organisms, and aquatic organism-consuming birds and mammals.

40

2.7.2.3 Toxicity Assessment A toxicity assessment was performed to identify whether contaminants detected at the site may cause effects on receptors and to determine benchmarks for comparison to exposure point concentrations and modeled doses. Benchmarks were derived from no observed adverse effects concentrations (NOAECs), dose-based no observed adverse effects levels (NOAELs), lowest observed adverse effects concentrations (LOAECs), and dose-based lowest observed adverse effects levels (LOAELs) from a large number of literature-based sources. To identify the potential for effects, concentrations and modeled doses were compared to benchmarks to develop an HQ. Site-specific bioavailability and bioaccumulation data were used to modify exposure point concentrations and modeled doses to provide more site-specific conclusions regarding risks. A hazard quotient greater than 1 indicates that there is a potential for adverse effects to occur. In addition to benchmarks, toxicity tests were performed using soil, sediment, and surface water from the sites to directly assess the toxicity of contaminants in environmental media; test results were compared to test results from unimpacted reference areas. 2.7.2.4 Risk Characterization The risk characterization for each site considered many factors as part of a weight of evidence approach. These included comparisons of exposure point concentrations to environmental media-based benchmarks; comparisons of doses modeled using total and bioavailable concentrations to benchmarks; toxicity test results; evidence of bioavailability, uptake, and bioaccumulation; spatial distribution of contaminants in relation to habitat; and comparisons between exposures and effects at the site and exposures and conditions at unimpacted reference areas. The following sections summarize the findings of the risk characterization for each of the two former small arms range sites.

Site 30a: Pistol Range The BERA assessed the potential for adverse effects on the survival, growth, and reproduction of a selected group of ecological receptors based on food web modeling and toxicological studies. Similar to the HHRA, ecological-based numeric criteria are used to identify the ecological COCs. As presented in Table 4, based on the results of the risk characterization, adverse effects to vermivorous mammals and vermivorous birds were attributed to lead (EA 2005c). Because data was not available to quantitatively assess reptiles and amphibians at the Pistol Range, these receptors were qualitatively assessed by examining whether or not other receptors were at risk.

Site 30b: Known Distance Range The BERA assessed the potential for adverse effects on the survival, growth, and reproduction of a selected group of ecological receptors based on food web modeling and toxicological studies (EA 2005c). As presented in Table 4, based on the results of the toxicological studies, receptors at risk from soil and sediment concentrations include the following: herbivorous mammals from lead and antimony; vermivorous mammals from copper and lead; vermivorous birds from lead;

41

Table 4: Chemicals of Concern for Ecological Receptors

Chemical of Concern Media of Concern

MinimumDetection (mg/kg)

MaximumDetection(mg/kg)

Mean (mg/kg)

Frequency of Detection Receptors

SITE 30A –PISTOL RANGE

Antimony 3.60 5.30 0.982 2/13 • Plants and soil invertebrates

Copper 10.5 177 51.7 13/13 • Plants and soil invertebrates

Lead

Soil

16.5 1,490 545 13/13 • Plants and soil invertebrates • Vermivorous birds and mammals • Herbivorous mammals

SITE 30B – KNOWN DISTANCE

Soil 2.60 677 132 10/14 • Plants and soil invertebrates • Herbivorous mammals • Vermivorous mammals

Antimony

Sediment 7.1 39.5 5.09 4/11 • Aquatic and benthic organisms • Amphibians and reptiles

Soil 10.6 1,010 217 17/17 • Plants and soil invertebrates • Vermivorous mammals

Copper Sediment 8.5 833 107 13/13

• Aquatic and benthic organisms • Amphibians and reptiles

Soil 15.4 170,000 16,500 17/17 • Plants and soil invertebrates • Herbivorous mammals • Vermivorous birds and mammals Lead

Sediment 26.9 7,900 1,090 13/13

• Aquatic and benthic organisms • Amphibians and reptiles

Soil 10.5 118 43.3 16/16 • Plants Zinc

Sediment 20.5 159 91.9 10/10 • Aquatic and benthic organisms • Amphibians and reptiles

Minimum, maximum, mean, and frequency values presented in this table represent data from the 2002-2004 BERA sampling events that included toxicity and sequential extraction procedure (SEP) analysis. Mean concentration calculations use one-half the detection limit for non-detectable concentrations. The values in this table use a subset (the risk assessment investigations) of the site data used to determine the RGs. RI data was used to determine the hotspots, and the risk data further evaluated the hotspots and have the SEP data. For this reason, sample numbers and values in this table may differ from those in other tables.

42

aquatic and benthic organisms from antimony, copper, lead, and zinc; and amphibians from antimony, copper, lead, and zinc (EA 2005c). Uncertainties There are a number of uncertainties associated with the ecological risk assessment. In many cases, model assumptions are chosen conservatively and may overestimate risk; site-specific data used in the risk assessment helps to decrease this likelihood. There is also uncertainty associated with reptiles and amphibians since data was unavailable to quantitatively assess these receptors and to develop remedial goals. In addition, data and benchmarks are unavailable for some contaminants, and thus there is related uncertainty. 2.7.3 BASIS FOR ACTION Concentrations of site-related COCs in sediment at the Known Distance Range only, and soil at both the Pistol Range and Known Distance Range, present unacceptable human health risk and may have adverse affects on ecological receptors. The response action selected in this ROD for the two former small arms range sites is protective of public health and welfare and the environment. 2.8 REMEDIAL ACTION OBJECTIVES Remedial Action Objectives (RAOs) are goals developed for the protection of human health and the environment. The RAOs for the 15 LUC Sites are to prevent residential exposure to any remaining contaminants in excess of residential risk criteria. At the two former small arms range sites, the following RAOs for soil (both sites) and sediment (Known Distance Range only) were developed based on an industrial land use:

• Prevent human/ecological exposure to contaminants at concentrations in excess of site-specific risk-based Remediation Goal (RG) in soil and sediment (Table 5) within the confines of each site; and

• Prevent migration of contaminants in soil and sediment that exceed site-specific risk-

based RGs (Table 5) to adjacent media or to offsite areas. The remedial alternatives discussed below focus on the COC-impacted soil at both of the former small arms range sites and sediment at the Known Distance Range only. The COCs and site-specific RGs established for both sites were presented in the FS (EA 2005d) and are shown in Table 5. As previously mentioned, human health risks and ecological risks are associated with both sites. Human health risk-based RGs are proposed cleanup levels, which are based on human health risks and are intended to be protective of human health based on a carcinogenic risk of 10-5. Ecological risk-based RGs were developed from the results of analytical testing, toxicology tests, and food-web modeling for identified ecological receptors.

43

The site-specific RGs for each COC were based on an evaluation of the calculated RGs for human health and ecological receptors. In general, the lowest calculated concentration for each COC, for either human or ecological receptors, was utilized as the RG, except where the RG was calculated to be below the established background concentration (Table 5). In these instances, the background value was utilized for the RG. Therefore, the RGs for each compound could vary from site to site based on the anticipated ecological receptors. The estimated volume of COC-impacted soil above RGs (i.e., area of attainment) that will be remediated at the two former small arms range sites is presented in Table 6. Estimated soil volumes within the area of attainment were calculated based on the analytical results of the 2003 Phase II RI and the risk assessments. Surface area was calculated using a plan view of analytical data points and estimating that COC-impacted soil was present to mid-way between sampling points. An average depth of 2 ft to 4 ft bgs was used to calculate the volume of COC-impacted soil. Figures 9 and 10 present estimated areas of each of the former small arms range sites that are expected to exceed site-specific RGs. Sampling and analysis will be performed during remediation to verify compliance with RGs and the precise dimensions of the areas of compliance.

Table 5: Final Risk-Based Remedial Goals

COC Surface Soil PRG (mg/kg)

Sediment PRG (mg/kg)

Source (mg/kg)

SITE 30A

Antimony 6 NA BERA

Arsenic 62.3 NA HHRA

Copper 110 NA BERA

Lead 1,000 NA USEPA

SITE 30B

Antimony 51 0.65 BERA

Copper 72 74 BERA

Lead 1,0002 608 USEPA

Mercury 1.2 1.44 BERA

Zinc 81.99 118 BERA 1Bolded Values represent background levels 2The human health risk-based Preliminary Remediation Goal (PRG) for lead is 1,000 mg/kg. Lead concentrations within the berm area at the Known Distance (KD) Range are predominately >1,000 mg/kg or near background. When considered spatially, remediating the area of 1,000 mg/kg or greater will result in the removal of the source and most of the impacted soil. After remediation, the KD Range as a whole is expected to provide a mean exposure point concentration protective of the robin population at the site (the BERA PRG for lead is 180 mg/kg).

Estimated Area Exceeding Remedial Goals And Land Use Control Boundary

Figure 9

Estimated Area Exceeding Remedial Goals And Land Use Control Boundary

Figure 10

44

Table 6: Estimated Soil Volumes Exceeding RGs Attainment

Area Length (feet)

Width (feet)

Depth (feet)

Cubic Feet

Cubic Yards

Tons

Site 30a: Pistol Range Impact Berm 400 14 4 22,400 830 1,162

Site 30b: Known Distance Range Sighting 350 10 4 14,000 482 675

Target Ditch (Sediment)

1500

20

2

60,000

2,222

3,110

Front Berm 1500 13 2 39,000 1,444 2,021 Rear Berm 1500 36 3 162,000 6,000 8,400

Totals 10,978 15,368

2.9 DESCRIPTION OF ALTERNATIVES This section presents a description of the remedial alternatives that were developed for the two former small arms range sites and the 15 LUC Sites. 2.9.1 TWO FORMER SMALL ARMS RANGE SITES

• Alternative 1—No Action. • Alternative 2—Land Use Controls-Site Use Restrictions. • Alternative 3—Excavation and Disposal. OEW clearance of removal areas and

excavation of COC-impacted soil. Physically separate soil and metallic debris by screening. Recycle separated metal debris. Sample soil for hazardous characteristics and dispose of at appropriate offsite landfill. LUCs to restrict future residential use.

• Alternative 4—Soil Washing. OEW clearance of removal areas and excavation of COC-

impacted soil. Physically separate soil and metallic debris by soil washing and screening. Sample soil for hazardous characteristics. Based on sampling results, re-apply washed soil as clean backfill to site surface. Dispose of characterized hazardous and non-hazardous soil at an appropriate offsite landfill. Recycle separated metal debris. LUCs to restrict future residential use.

• Alternative 5—Encapsulation. OEW clearance of removal areas and excavation of

COC-impacted soil. Physically separate soil and metallic debris by screening. Stabilize excavated soil with silica micro-encapsulation. Sample soil for stability and hazardous characteristics. Dispose of soil as non-hazardous waste at an offsite landfill facility. Recycle separated metal debris. LUCs to restrict future residential use.

• Alternative 6—Stabilization. OEW clearance of removal areas and excavation of COC-

impacted soil. Physically separate soil and metallic debris by screening. Stabilize

45

excavated soil with soluble phosphate or similar. Sample soil for stability and hazardous characteristics. Dispose of soil as non-hazardous waste at an offsite landfill facility. Recycle separated metal debris. LUCs to restrict future residential use.

Except for Alternative 1, the no-action alternative, all alternatives share the following common LUCs:

1. Installation Master Plan use restriction on military family housing, non-military residential housing, elementary and secondary schools, child care facilities, and playgrounds; and

2. Periodic inspections and reports.

2.9.1.1 Alternative 1: No Action For both sites: Estimated Capital Cost: $0 Estimated Present Worth O&M Cost: $54,000 Estimated Total Present Worth Cost: $54,000 Estimated Construction Timeframe: 0 Estimated Time to Achieve RAOs: 0 Pursuant to Section 300.430(e)(3)(ii)(6) of the revised NCP, the “No Action” alternative is developed to provide a baseline against which the other remedial alternatives are to be compared. Evaluation of this alternative in the FS assumed that LUCs would not be implemented and actions, such as LUCs, would not continue. The FS also indicated that remedy reviews every 5 years would be required because the contamination remaining onsite would not allow for unlimited use and unrestricted exposure. The cost estimate is based on performing the remedy reviews six times during a 30-year period. Because no remedial actions would be specified for Alternative 1, applicable or relevant and appropriate requirements (ARARs) are not applicable. 2.9.1.2 Alternative 2: Land Use Controls For both sites: Estimated Capital Cost: $567,000 Estimated Present Worth O&M Cost: $54,000 Estimated Total Present Worth Cost: $621,000 Estimated Construction Timeframe: 3 months Estimated Time to Achieve RAOs: 0

46

Alternative 2 involves administrative land use and access controls, which will limit use, development, and exposure at the site. LUCs would prevent human receptors from contacting range soil and potential range hazards by creating administrative restrictions, and limiting future development in impacted areas. Administrative restrictions include amending the Installation Master Plan to note restrictions on potential development, development-related activities, and the potential presence of UXO. In addition, administrative security measures including limiting personnel authorized to access the site, creating notification procedures for site access, and limiting/tracking authorized activities could be implemented. Pursuant to CERCLA Section 121(c), 5-year reviews would be conducted to protect human health and the environment as long as deemed necessary based on the presence of COCs above health-based levels. The LUC alternative would not comply with chemical-specific ARARs because no action would be taken to address the COCs detected at concentrations above RGs. The LUC alternative may not comply with location-specific ARARs because of potential impacts to protected resources at APG. Because no remedial actions would be specified, action-specific ARARs are not applicable to this alternative. 2.9.1.3 Alternative 3: Excavation and Disposal For both sites: Estimated Capital Cost: $5,088,000 Estimated Present Worth O&M Cost: $54,000 Estimated Total Present Worth Cost: $5,142,000 Estimated Construction Timeframe: 12 months Estimated Time to Achieve RAOs: 12 months This remedial alternative involves clearing removal areas of OEW and excavating COC-impacted soil for offsite disposal as hazardous waste, and would address the RAOs through the following remedial components:

• Identification and removal of OEW materials from excavation areas; • Excavation of soil impacted above RGs (approximately 15,368 tons) and separation of

metal debris from impacted soil by physical separation techniques; • Transport and disposal of impacted soil at an appropriate offsite landfill for hazardous

waste as well as recycling/disposal of screened metallic debris; • Post-removal confirmation sampling of excavated areas; • LUCs to prohibit military family housing, childcare, schools, playgrounds, and non-

military residential land use; and

47

• 5-Year Reviews by APG. Various inorganic COCs in the firing ranges’ soil were reported at concentrations above RGs. Alternative 3 will satisfy chemical-specific ARARs by removal of impacted soil. Alternative 3 would comply with location-specific ARARs regulating military firing ranges, UXO, and ecological receptors. Alternative 3 would be conducted in compliance with action-specific ARARs related to soil removal, onsite hazardous waste storage, hazardous and non-hazardous waste disposal, and monitoring. 2.9.1.4 Alternative 4: Soil Washing For both sites: Estimated Capital Cost: $2,731,000 Estimated Present Worth O&M Cost: $54,000 Estimated Total Present Worth Cost: $2,785,000 Estimated Construction Timeframe: 12 months Estimated Time to Achieve RAOs: 12 months This remedial alternative involves clearing removal areas of OEW and excavating COC-impacted soil for soil washing separation prior to offsite disposal. Alternative 4 would address the RAOs through the following remedial components:

• Identification and removal of OEW materials from excavation areas; • Excavation of soil impacted above RGs (approximately 15,368 tons) and separation of

metal debris and particulate metal from impacted soil by physical separation and soil washing techniques;

• Removal and concentration of COCs from soil into a smaller volume of soil by soil

washing techniques; • Transport and disposal of impacted soil at an appropriate offsite landfill for hazardous or

non-hazardous waste as well as recycling/disposal of screened metallic debris (soil below RGs will be spread onsite);

• Post-removal confirmation sampling of excavated areas; • LUCs to prohibit military family housing, childcare, schools, playgrounds, and non-

military residential land use; and • 5-Year Reviews by APG.

Various inorganic COCs in the firing ranges’ soil were reported at concentrations above RGs. Alternative 4 will satisfy chemical-specific ARARs by removal of all impacted soil. Alternative 4 would comply with location-specific ARARs regulating military firing ranges,

48

UXO, and ecological receptors. Alternative 4 would be conducted in compliance with action-specific ARARs related to soil removal, onsite hazardous waste storage, hazardous and non-hazardous waste disposal, and monitoring. 2.9.1.5 Alternative 5: Encapsulation For both sites: Estimated Capital Cost: $4,125,000 Estimated Present Worth O&M Cost: $54,000 Estimated Total Present Worth Cost: $4,179,000 Estimated Construction Timeframe: 12 months Estimated Time to Achieve RAOs: 12 months This remedial alternative involves clearing removal areas of OEW and excavating COC-impacted soil for separation and stabilization prior to offsite disposal. Alternative 5 would address the RAOs through the following remedial components:

• Identification and removal of OEW materials from excavation areas; • Excavation of soil impacted above RGs (approximately 15,368 tons) and separation of

metal debris from impacted soil by physical separation techniques; • Stabilization of excavated soil with a silica amendment to reduce toxicity and

bioavailability; • Transport and disposal of impacted soil at an appropriate offsite landfill for non-

hazardous waste as well as recycling/disposal of screened metallic debris; • Post-removal confirmation sampling of excavated areas; • LUCs to prohibit military family housing, childcare, schools, playgrounds, and non-

military residential land use; and • 5-Year Reviews by APG.

Various inorganic COCs in the firing ranges’ soil were reported at concentrations above RGs. Alternative 5 will satisfy chemical-specific ARARs by removal of all impacted soil and stabilizing the soil below TCLP criteria for non-hazardous waste disposal. Alternative 5 would comply with location-specific ARARs regulating military firing ranges, UXO, and ecological receptors. Alternative 5 would be conducted in compliance with action-specific ARARs related to soil removal, onsite hazardous waste storage, hazardous and non-hazardous waste disposal, and monitoring.

49

2.9.1.6 Alternative 6: Stabilization For both sites: Estimated Capital Cost: $3,904,000 Estimated Present Worth O&M Cost: $54,000 Estimated Total Present Worth Cost: $3,958,000 Estimated Construction Timeframe: 12 months Estimated Time to Achieve RAOs: 12 months This remedial alternative involves clearing removal areas of OEW and excavating COC-impacted soil for separation and stabilization prior to offsite disposal. Alternative 6 would address the RAOs through the following remedial components:

• Identification and removal of OEW materials from excavation areas; • Excavation of soil impacted above RGs (approximately 15,368 tons) and separation of

metal debris from impacted soil by physical separation techniques; • Stabilization of excavated soil with a soluble phosphate amendment (or similar) to reduce

toxicity and bioavailability; • Transport and disposal of impacted soil at an appropriate offsite landfill for non-

hazardous waste as well as recycling/disposal of screened metallic debris; • Post-removal confirmation sampling of excavated areas; • LUCs to prevent military housing, non-military residential housing, elementary and

secondary schools, child care facilities, and playgrounds in this area; and • 5-Year Reviews by APG.

Various inorganic COCs in the firing ranges’ soil were reported at concentrations above RGs. Alternative 6 will satisfy chemical-specific ARARs by removal of all impacted soil and stabilizing the soil below TCLP criteria for non-hazardous waste disposal. Alternative 6 would comply with location-specific ARARs regulating military firing ranges, UXO, and ecological receptors. Alternative 6 would be conducted in compliance with action-specific ARARs related to soil removal, onsite hazardous waste storage, hazardous and non-hazardous waste disposal, and monitoring. 2.9.2 15 LUC SITES 2.9.2.1 Alternative 1: No Action Pursuant to Section 300.430(e)(3)(ii)(6) of the revised NCP, the “No Action” alternative is developed to provide a baseline against which the other remedial alternatives are to be compared.

50

Remedy reviews every 5 years would be required because the contamination remaining onsite would not allow for unlimited use and unrestricted exposure. As remedy reviews every 5 years are already being implemented for the OAA sites, there is no cost associated with remedy reviews for these sites. 2.9.2.2 Alternative 2: Land Use Controls The 15 LUC sites do not require further response action based on a reasonably anticipated industrial/military exposure scenario; however, to support anticipated future use of the site for industrial/military purposes, a use restriction would be implemented to prevent future military family housing, elementary and secondary schools, child care facilities, playgrounds, and non-military residential land use. LUCs would prevent human receptors from contacting range soil and potential range hazards by restricting future residential development in impacted areas. Administrative restrictions include amending the APG Geographical Information System (GIS) and the Installation Master Plan to restrict military family housing, non-military residential housing, elementary and secondary schools, child care facilities, and playgrounds usage. The installation of potable wells within the site boundaries will also be restricted. Pursuant to CERCLA Section 121(c), 5-year reviews would be conducted to protect human health and the environment as long as deemed necessary based on the presence of COCs above health-based concentrations. As remedy reviews every 5 years are already being implemented for the OAA sites, there is no cost associated with remedy reviews for these sites. 2.10 COMPARATIVE ANALYSIS OF ALTERNATIVES To evaluate the remedial alternatives for the two former small arms range sites and the 15 LUC Sites, the potential performance of each alternative is considered in terms of the nine evaluation criteria required by the NCP:

• protection of human health and the environment; • compliance with ARARs; • long-term effectiveness; • reduction of toxicity, mobility, or volume through treatment; • short-term effectiveness; • implementability; • cost; • state acceptance; and • community acceptance.

A summary of the comparative analysis of each remedial alternative for the two former small arms range sites is presented in Table 7. The nine criteria are then categorized into one of the three following groups:

51

• Threshold criteria, which are requirements that each alternative must meet in order to be eligible for selection;

• Primary balancing criteria, which are used to weigh major trade-offs among alternatives;

and • Modifying criteria, which are considered after receipt of comments on the preferred

alternative and other alternatives presented in the proposed plan, and which indicate whether the State and the community support the selected alternative. In the final balancing of trade-offs between alternatives upon which the final remedy selection is based, modifying criteria are of equal importance to the balancing criteria.

2.10.1 TWO FORMER SMALL ARMS RANGE SITES 2.10.1.1 Threshold Criteria Overall Protection of Human Health and the Environment Alternative 1 would not achieve RGs at the Pistol Range and Known Distance Range. Alternative 1 is eliminated from further consideration under the remaining eight criteria since this alternative is not protective of human health and the environment. Alternative 2 would be protective of human health, based on an industrial land use scenario; however, this alternative does not address other metals that are co-located with the lead and identified as ecological COCs. Alternative 2 is eliminated from further discussion since this alternative may not be protective of the environment. Alternative 3 would be protective of human health and the environment, based on an industrial land use scenario, through use restrictions, excavation and processing of soil exceeding RGs, offsite disposal of impacted soil, and confirmation monitoring of excavated areas. Use restrictions would ensure that the Pistol Range and Known Distance Range remain classified for industrial use. In addition, data from confirmation monitoring would be utilized to verify that Alternative 3 is effective in attaining RAOs. Alternative 4 would be protective of human health and the environment, based on an industrial land use scenario, through use restrictions, excavation of soil exceeding RGs, soil washing, offsite disposal of impacted soil, reuse of soil below RGs, and confirmation monitoring of excavated areas. Use restrictions would ensure that the Pistol Range and Known Distance Range remain classified for industrial use. Data from confirmation monitoring would be utilized to verify that Alternative 4 is effective in attaining RAOs. Alternative 5 would be protective of human health and the environment, based on an industrial land use scenario, through use restrictions, excavation of soil exceeding RGs, stabilization of excavated soil via silica micro encapsulation, offsite disposal of impacted soil, and confirmation monitoring of excavated areas. Use restrictions would ensure that the Pistol Range and Known

52

Distance Range remain classified for industrial use. In addition, data from confirmation monitoring would be utilized to verify that Alternative 5 is effective in attaining RAOs. Alternative 6 would be protective of human health and the environment, based on an industrial land use scenario, through use restrictions, excavation of soil exceeding RGs, stabilization of excavated soil with a soluble phosphate agent (or similar), offsite disposal of impacted soil, and confirmation monitoring of excavated areas. Use restrictions would ensure that the Pistol Range and Known Distance Range remain classified for industrial use. In addition, data from confirmation monitoring would be utilized to verify that Alternative 6 is effective in attaining RAOs. Compliance With Applicable or Relevant and Appropriate Requirements Alternatives 3 through 6 would be conducted in compliance with location-specific ARARs regulating wetlands, floodplains, and proximity to surface water, and action-specific ARARs related to soil removal, onsite storage of hazardous waste, hazardous and non-hazardous waste disposal (including potential land disposal restrictions), OEW removal, and monitoring (Table 10). There are no chemical-specific ARARs because there are no promulgated Federal or State standards for metals in soil. 2.10.1.2 Primary Balancing Criteria Long-Term Effectiveness Alternative 3 reduces residual risk through the removal of impacted soil at the Pistol Range and Known Distance Range. The removal of soil exceeding RGs from the sites effectively removes the potential long-term risk pathways for human and ecological receptors. Soil removal, revegetation/habitat replacement, and offsite soil disposal are all reliable and proven technologies with minor long-term maintenance or residual risk. Alternative 4 reduces residual risk through the removal and washing of impacted soil at each site. The removal of contaminated soil exceeding RGs from each site effectively removes the long-term risk pathways for human and ecological receptors. Soil removal, soil washing, revegetation/habitat replacement, and offsite soil disposal are reliable and proven technologies with minor long-term maintenance or residual risk. Alternatives 5 and 6 reduce residual risk through the removal and stabilization of impacted soil at each site. The removal of contaminated soil exceeding RGs from each site effectively removes the long-term risk pathways for human and ecological receptors. Stabilization via silica micro encapsulation (Alternative 5) will reduce the hazards of COCs at the disposal location. Stabilization with a phosphate agent (Alternative 6) has been demonstrated to reduce toxicity, and therefore leachate, as well as bioavailability over the long-term. Soil removal, stabilization, revegetation/habitat replacement, and offsite soil disposal are reliable and proven technologies with minor long-term maintenance or residual risk.

53

Table 7: Comparative Analysis Summary of Remedial Alternatives Site 30a: Pistol Range and Site 30b: Known Distance Range

Criteria

Alternative 1 – No Action

Alternative 2⎯ Land Use Controls

Alternative 3⎯ Excavation and

Disposal

Alternative 4⎯ Soil Washing

Alternative 5⎯ Encapsulation

Alternative 6⎯ Stabilization

Overall Protection of Human Health and the Environment

∇ ∇ Δ Δ Δ Δ

Compliance With ARARs NA ∇ Δ Δ Δ Δ Long-Term Effectiveness and Permanence

∇ ∇ Δ Δ Δ Δ

Reduction of Toxicity, Mobility, and Volume ∇ ∇ Δ Δ Δ Δ Short-Term Effectiveness ∇ ∇ Δ Δ Δ Δ Implementability Δ Δ Δ Δ Δ Δ Estimated Construction Timeframe NA NA 1 year 1 year 1 year 1 year

Total Cost (30-Year Present Worth) $54,000 $621,000 $5,142,000 $2,785,000 $4,179,000 $3,958,000

State Acceptance ∇ ∇ Δ Δ Δ Δ Community Acceptance ∇ ∇ Δ Δ Δ Δ Notes: Δ – In comparison with other alternatives, complies well with criteria. ♦ – In comparison with other alternatives, partially complies with criteria. ∇ – In comparison with other alternatives, does not comply as well with criteria. NA-Not Applicable Cost estimates are based upon 2003 dollars. Total costs are rounded to the nearest $100 (or to the nearest $1,000 if greater than $10,000). Total Net Cost rounded to nearest $1,000.

54

Alternatives 3 through 6 use land use restrictions consisting of an amendment to the Installation Master Plan to ensure that the Pistol Range and Known Distance Range remain classified for industrial use. Reduction of Toxicity, Mobility, and Volume Through Treatment No treatment is proposed to be used in Alternatives 3 and 4. The Alternative 3 process removes site soil that exceeds RGs and disposes of the soil offsite, and the Alternative 4 process subjects the COC-impacted soil to an extensive wash treatment process that will concentrate COCs into a reduced volume of waste. However, the toxicity, mobility, and volume of each COC under Alternatives 3 and 4 are not permanently reduced but are separated out and transferred to appropriate disposal facilities. Alternatives 5 and 6 would reduce contaminant toxicity and mobility by encapsulation and stabilization. The Alternative 5 process includes excavation and removal of impacted soil that exceeds RGs and stabilization through encapsulation of excavated soil to reduce toxicity and mobility of COCs at the offsite disposal location. The Alternative 6 process stabilizes the excavated COC-impacted soil with a phosphate agent (or similar), which creates a stable, insoluble mineral that would reduce leaching and potential migration of COCs at an offsite disposal facility. However, through Alternatives 5 and 6, the stabilization process will increase the volume of impacted soil by 5 percent, as a stabilizer is combined with impacted soil to form a homogenous mix. Short-Term Effectiveness Alternatives 3, 4, 5, and 6 have the potential for harm to human and ecological habitat in the short-term due to potential contact with disturbed soil and UXO during remedial activities. Potential occupational risks to site workers from UXO or soil direct contact will require adherence to a site safety and health plan, Occupational Safety and Health Administration (OSHA) health and safety procedures, and proper use of personal protective equipment. Revegetation and site reconstruction following remedial activities will re-establish these ecological habitats, mitigating the short-term impacts. Remedial activities are expected to be completed and meet RAO performance standards within a 1-year time frame at each site. Implementability Alternatives 3 through 6 are implementable based on numerous case studies on each of these four alternatives. Additional remedial actions related to residual risk or sources will not be prevented by the implementation of any of the four alternatives. Cost Alternative 3 has the highest capital costs given the costs associated with the quantity of soil requiring hazardous waste disposal. Alternatives 5 and 6 are close in cost, as both involve mixing a similar volume of additive to the soil for ex situ stabilization. These costs may vary dependent on the actual additive to soil ratio determined through a treatability study.

55

Alternative 4 is the lowest cost of the treatment options, given the economies of scale from combining a wash system with reuse of washed soil that is below RGs. As Alternatives 3 through 6 all involve processes that would meet RAOs, including the removal of impacted soil within 1 year, O&M costs are negligible. Five-year reviews would be conducted to ensure that LUCs remain in place at the sites. In summation, total costs (as adjusted for present worth over the specified time periods) are as follows:

• Alternative 1⎯No Action (30 years) are $54,000 for the 5 year reviews; • Alternative 2⎯LUCs (30 Years) are $621,000 for the site restrictions and 5-year reviews; • Alternative 3⎯Offsite Disposal (30 years): $5,142,000; • Alternative 4⎯Soil Washing (30 Years): $2,785,000; • Alternative 5⎯Encapsulation (30 Years): $4,179,000; and • Alternative 6⎯Stabilization (30 years): $3,958,000.

A comparative analysis of remedial alternatives for each site is summarized in Table 7. 2.10.1.3 Modifying Criteria State Acceptance The MDE Waste Management Administration reviewed and commented on the remedial alternatives. MDE accepts the Selected Remedy for the Two Former Small Arms Range Sites. Community Acceptance A full transcript of the Public Meeting held on 21 September 2006 is available in the Administrative Record. In general, the community is supportive of the Selected Remedies for the Two Former Small Arms Range Sites. Responses to written comments received from the community are presented in Chapter 3 of this document. 2.10.2 15 LUC SITES 2.10.2.1 Threshold Criteria Overall Protection of Human Health and the Environment Alternative 1 may not ensure land use remains consistent with exposure assumptions. Alternative 1 is eliminated from further consideration under the remaining eight criteria since this alternative may not be protective of human health and the environment. Alternative 2 would be protective of human health by preventing military family housing, non-military residential housing, elementary and secondary schools, child care facilities, and playgrounds usage.

56

Compliance With Applicable or Relevant and Appropriate Requirements Alternative 2 does not have associated ARARs. 2.10.2.2 Primary Balancing Criteria Long-Term Effectiveness Alternative 2 is dependant upon the implementation of the LUCs to provide long-term effectiveness and permanence. No change in land use is expected for these sites. Reduction of Toxicity, Mobility, and Volume Through Treatment Alternative 2 would not result in the reduction of toxicity, mobility, or volume through treatment. Short-Term Effectiveness Alternative 2 would be implemented quickly and would be effective in the short-term. Implementability Alternative 2 can be easily implemented. Cost Alternative 2 would not have associated costs. The costs associated with these sites would be captured with the implementation of LUCs for the former small arms range sites. 2.10.2.3 Modifying Criteria State Acceptance The MDE Waste Management Administration reviewed and commented on the remedial alternatives. MDE accepts the Selected Remedies for the 15 LUC Sites. Community Acceptance A full transcript of the Public Meeting held on 21 September 2006 is available in the Administrative Record. In general, the community is supportive of the Selected Remedies for the 15 LUC Sites. Responses to written comments received from the community are presented in Chapter 3, Responsiveness Summary, of this document.

57

2.11 PRINCIPAL THREAT WASTES Principal Threat Wastes at the Two Former Small Arms Ranges Sites include the lead bullets/fragments in the soil berms. Alternatives 1 and 2 would leave the lead bullets/fragments in-place while Alternatives 3, 4, 5, and 6 would physically remove the metallic debris from the soil for recycling/disposal. 2.12 SELECTED REMEDY 2.12.1 TWO FORMER SMALL ARMS RANGE SITES The Selected Remedy for the two former small arms range sites is Alternative 6⎯OEW Clearance, Excavation, Stabilization, Offsite Disposal, and LUCs. Alternative 6 is expected to meet all the specific RAOs determined, based on review of available data and all ARARs. The remediation costs for Alternative 6, as estimated in the FS (EA 2005d), for each site are presented in Table 8. The total estimated cost, rounded to the nearest $100,000, for both sites is $4,000,000. The Selected Remedy for the two former small arms range sites is intended to prevent human exposures to COCs at levels presenting unacceptable risk and prevent migration of COCs from the two sites. The Selected Remedy is designed to reduce or eliminate the potential risks to human or ecological receptors via excavation, stabilization of impacted soil, and offsite/off-Post disposal of contaminated soils with LUCs to restrict future residential use. Under this alternative, contaminated soil above RGs (Tables 5 and 6; Pages 43 and 44, respectively) for the two former small arms range sites will be removed, as presented on Figures 9 and 10. Alternative 6 will include the following actions for both sites:

• Conduct range clearance activities to identify and remove OEW materials from

excavation areas; • Excavation of approximately 15,368 tons of soil impacted above RGs(shown in the Table

5 on page 43) and separation of metal debris and particulate metal from impacted soil by physical separation;

• Stabilization of excavated soil with a soluble phosphate amendment (or similar) to reduce

toxicity and bioavailability; • Transport and disposal of impacted soil at an appropriate offsite landfill for non-

hazardous waste as well as recycling/disposal of screened metallic debris; • Post-removal confirmation sampling of excavated areas; • LUCs to restrict future residential use; and

58

• 5-Year Reviews by APG. Alternative 6 was selected as it was determined to meet all the specific RAOs and all of the reviewed ARARs, is readily implementable, and is one of the most cost-effective alternatives reviewed. Excavated soil will be processed to recover debris and particles (greater than 2-in. diameter) from COC-impacted soil. Particulate debris such as spent munitions, unexploded small arms rounds, and metal debris will be separated from COC-impacted soil utilizing physical separation techniques. A treatability study will be conducted to establish design parameters for an effective separation process based on contaminants, geology, and particulate size. Physical separation methods commonly utilized for firing range remediation include attrition wet-screening, and gravity separation. Approximately 5 percent of the total soil volume has been conservatively estimated as particulate debris that can be recovered by separation techniques based on small-arms firing range remediation case studies (Battelle 1997). Approximately 14,600 tons of impacted soil will require stabilization following physical separation of particulate contaminants. Additional volume for excavation, stablilization, and disposal could be required to meet the RGs at the site. A treatability study will be necessary to determine the appropriate amendment mixture and dose rate in relation to geologic and COC characteristics including soil type, moisture content, COC concentrations, pH, and cation exchange capacity. Impacted soil and stabilization amendments will be mixed ex-situ from screened stockpiles and will include the use of pug mills and specialized mixing equipment such as road reclaimers. Mixing will continue until a homogenous mix of impacted soil and stabilizing amendment is created. Stockpiles will be sampled for RCRA hazardous waste characterization based on the daily throughput of the soil processing operation with a minimum of one composited sample per 250 yd3. Soil not meeting TCLP requirements will be retreated to meet non-hazardous criteria. Soil stockpiles will be managed as hazardous waste during the remedial process until daily sampling results consistently indicate the soil stockpiles are non-hazardous. Additionally, sumps will be created to contain rain water runoff prior to sampling and analysis and proper disposal of the collected water. Soil characterized as non-hazardous waste will be transported and disposed of in accordance with applicable U.S. Department of Transportation (USDOT) and RCRA regulations at a RCRA Subtitle D Landfill. Soil characterized as non-hazardous and below the RGs may be used onsite as backfill. Confirmation soil samples will be collected in the excavated areas and analyzed for TAL metals to confirm complete excavation of soil impacted above RGs. An X-ray fluorescence (XRF) survey will supplement laboratory analysis to further confirm site remediation.

59

Table 8: Alternative 6⎯Excavation, Stabilization, and Offsite Disposal

Item Description Quantity Unit Cost ($) Total Cost ($)

1 Mobilization

1.1 Equipment Mobilization-2 Sites 2 Lump Sum 30,000

2 Staging Area

2.1 Geotextile Cover 5,000 yds 3 15,000

2.2 Fencing 1200 lf 12 14,000

3 Site Prep

3.1 Clear/Grub Vegetation-Wet 4 acres 3000 12,000

3.2 Vegetative Waste-Staging/Transport 80 tons 10 1,000

3.3 Dust Control 19360 yds2 0.5 10,000

3.4 Equipment Decontamination 1 Lump Sum 40,000

4 Excavation

4.1 Mechanical Excavation 15,368 tons 7 108,000

4.2 Transport/Staging 15,368 tons 7.5 115,000

4.3 OEW Removal Oversight 76 days 175 13,000

5 Stabilization

5.1 Stabilization Bench Scale Study-including sample collection and analysis 2 Sites Lump Sum 15,000

5.2 Physical Separation Plant-attrition wet screen, gravity separation 15,368 tons 40 615,000

5.3 Soil Mixing Equipment/Labor 61 days 350 22,000

5.4 Soluble Phosphate Treatment (5% of Screened Soil) 14,600 tons 30 438,000

5.5 Stockpile Composite Sample Analysis-one sample per 250 cy; Tal Metals and TCLP Analysis

46 samples 140 6,000

5.6 Oversight; Stockpile Sampling and Reporting 104 Days 650 68,000

6 Transport and Disposal

6.1 Non-Hazardous Waste Transport/Disposal 15,368 tons 75 1,153,000

6.2 Scrap Metal Recycling 770 tons 50 39,000

7 Confirmation Sampling

7.1 Confirmation Sample Analysis-TAL Metals 50 samples 95 5,000

7.2 Confirmation Sampling, XRF Survey, and Reporting 1 Lump Sum 30,000

8 Site Reconstruction

8.1 Revegetate Excavation Areas 1 Lump Sum 15,000

9 Site Closure

9.1 Remedial Action Closure Report 1 Lump Sum 25,000

SUBTOTAL 2,789,000

10 Adjustments

10.1 Management, Permitting, and Site Services 15% 418,000

60

Table 8 (Continued): Alternative 6⎯Excavation, Stabilization, and Offsite Disposal

Item Description Quantity Unit Cost ($) Total Cost ($)

10.2 Contingency 25% 697,000

TOTAL CAPITAL COSTS 3,904,000

Operations and Maintenance

11 Review Costs

11.1 Five Year Reviews (30 Years) 6 15,000 90,000

SUBTOTAL 90,000

TOTAL REVIEW COSTS 90,000

Total 30-Year Present Worth 54,000

30-Year Present Worth = (O&M)*(P/A, 3.2%, 30 years)

Annual Review Cost (Every 5 Years) = $ 15,000

TOTAL NET PRESENT WORTH COST 4,000,000

Cost estimates are based upon 2004 dollars. Total costs are rounded to the nearest $100 (or to the nearest $1,000 if greater than $10,000). Total Net Present Worth cost is rounded to the nearest $100,000.

Upon completion of confirmation sampling and analysis, site reconstruction activities will be conducted to mitigate the impacts of excavation. Reconstruction activities will include placement of clean fill such as sand and gravel to stabilize excavation areas, re-establishment of bottom topography, and habitat replacement. In addition to excavation areas, banks and shoreline areas immediately adjacent to soil removal areas may require stabilization to control bank erosion, slumping, and sloughing. Revegetation efforts will consist of site appropriate vegetation including aquatic and wetland species. Following the remedial actions at the sites, contamination may remain that may exceed residential criteria. Therefore, LUCs will then be implemented to restrict future residential use of the site. In addition, the LUC will also include a provision to prevent the disturbance of the soil berms at depths greater than 2 ft, the minimum depth of the remediation. LUCs will be maintained until the concentrations of hazardous substances in the soil are reduced to levels that allow for unlimited use and unrestricted exposure. Figures 9 and 10 present the area boundaries for each site where the LUCs objective will be applied and maintained. The Remedial Design will be submitted in accordance with the remedial design schedule provisions of the FFA and will include a LUC component describing the details of LUC implementation and maintenance, including periodic inspections. The Army shall be responsible for implementation, maintenance, periodic reporting, and enforcement of LUCs in accordance with the Remedial Design. Although the Army may transfer these responsibilities to another party by contract, property transfer agreement, or through other means, the Army shall remain ultimately responsible for remedy integrity and shall perform the following: (1) CERCLA 121(c) 5-year reviews; (2) notification of the appropriate regulators and/or local government representatives of any known LUC deficiencies or violations; (3) provide access to the property to conduct any necessary response; (4) retain the ability to change, modify, or terminate LUCs and any related

61

deed or lease provisions; and (5) ensure that the LUC objective is met to maintain remedy protectiveness. As a condition of the property transfer or lease, the Army may require the transferee or lessee in cooperation with other stakeholders to assume responsibility for various implementation actions. Third party LUC responsibility will be incorporated into pertinent contractual, property, and remedial documentation, such as a purchase agreement, deed, lease, and Remedial Design addendum. To the extent permitted by law, a transfer deed shall require 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, consistent with federal and state law, 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 LUCs. Pursuant to CERCLA Section 121(c), 5-year reviews are conducted to protect human health and the environment as long as deemed necessary based on the presence of COCs above health-based levels. The NCP further provides that remedial actions which result in any hazardous substances, pollutants, or contaminants remaining at the site above levels that allow for unlimited use and unrestricted exposure be reviewed every 5 years to ensure protection of human health and the environment. Although this alternative will remove all RG-impacted soil, the sites will still have LUCs to restrict residential use and exposure scenarios. Since contaminants will remain in site soil at levels that do not allow for unlimited use, 5-year reviews will be conducted in accordance with CERCLA. Based on the available information, the Army, EPA, and MDE support the Preferred Alternatives for the two former small arms range sites, as consistent with these criteria and necessary to protect human health and the environment. The Army, EPA, and MDE support the Preferred Alternative as compliant with the following statutory requirements of CERCLA Section 121(b):

1. be protective of human health and the environment; 2. comply with ARARs; 3. be cost-effective; 4. utilize permanent solutions and alternative treatment technologies or resource recovery

technologies to the maximum extent practicable; and 5. satisfy the preference for treatment as a principle element when justified.

62

2.12.2 15 LUC SITES Based on the results of the Remedial Investigation, the Army has determined that limited CERCLA Remedial Action (i.e., LUCs) is necessary to protect human health or the environment for the 15 LUC Sites. This determination is based on site uses for industrial and/or military purposes. At the 15 LUC sites, as outlined in Table 9, use restrictions have been or will be implemented through the APG installation master plan to further ensure that land use remains consistent with the exposure assumptions used to analyze risk to human health and the environment, to include prohibition of military family housing, childcare, schools, playgrounds, and non-military residential land use of this property. Figures 11, 12, and 13 present the area boundaries for each LUC Site where the LUCs objective will be applied and maintained. As part of the CERCLA 121(c) five year reviews for the Two Small Arms Ranges, the Army will confirm that use restrictions remain in place at these sites until the concentrations are reduced to levels that allow for unlimited use and unrestricted exposure. As a condition of any future property transfer or lease, the Army will require the transferee or lessee in cooperation with other stakeholders to assume responsibility for various use restriction implementation actions. Third party LUC responsibility will be incorporated into pertinent contractual and property documentation, such as a purchase agreement, deed, or lease. To the extent permitted by law, a transfer deed shall require the existing use restrictions 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, consistent with federal and state law, upon transfer of the title grant the State an environmental covenant or easement that would allow the State to enforce use restrictions 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 use restrictions. Table 9: Summary of Restrictions for the 23 Sites, Other Aberdeen Areas, APG, Maryland

Site No

Restrictions No

Restrictions Rationale

Site 3: Churchville Test Course Dump X RI sample results are within background

concentrations. Site 4: Outdoor Pesticide Mixing Area at Bldg 5010 X Soil removal was conducted to industrial criteria.

Site 5: DPW Backyard Storage Area Near Bldg 5262 X Soil removal was conducted to industrial criteria.

Site 6: DDT Spill Near Bldg 450 X Soil removal was conducted to industrial criteria.

Site 7: Spent Lead Acid Battery Site Near Bldg 2351 X Soil removal was conducted to industrial criteria.

Site 10: Bldg 5039 Battery Shop X RI sample results are below industrial screening

criteria. Site 11: Old Burn Trench on Spesutie Island X

RI soil sample results are below industrial screening criteria. No MCL exceedances.

A burn trench was not identified.

63

Table 9 (Continued): Summary of Restrictions for the 23 Sites,

Other Aberdeen Areas, APG, Maryland

Site No Restrictions

No Restrictions

Rationale

Site 13: Chemical Dump Ponds on Spesutie Island X

No industrial risks were identified in the RI sampling. Site is within tidal marsh and an

active range area. Site 14: Former Burning Area Near Bldg 1171 X RI sample results are within background

concentrations. Site 15: Metal Barricade Near Bldg 1122 X RI sample results are within background

concentrations. Site 18: Barrels Near Bldg 510 X Soil removal was conducted to industrial criteria.Site 19: Sandblast Area Near Bldg 523 X Soil removal was conducted to industrial criteria.

Site 20: Potential Explosives in Groundwater Area X No source areas have been identified and site is

within active range areas. Site 21: POL Facility Sand Pit Near Bldg 5215 X Soil removal was conducted to industrial criteria.

Site 22: Bldgs 309 and 390 Storm Sewer Outfalls X No industrial risks were identified in the RI

sampling. Site 24: White Phosphorous Munitions Land Burial Area X Site was not located and is within an active

range area. Site 27: German Ammunition Train Explosion Area X Site is within an active range area.

Site 28a: Bldg 436 UST Site X

UST has been removed and there were no MCL exceedances. Site has been addressed by UST

Program. Site 28b: Bldg 456 AST Site X

AST has been removed and there were no MCL exceedances. Site has been addressed by UST

Program.

Site 28c: Bldg 2458 UST Site X UST has been removed and there are no current MCL exceedances. Site has been addressed by

UST Program. Site 28d: Bldg 3329 UST Site X

UST has been removed and there are no current MCL exceedances. Site has been addressed by

UST Program. Site 28e: Bldg 3505 UST Site X

UST has been removed and there are isolated MCL exceedances, but these do not constitute a

plume per USEPA Hydrogeologist. Site has been addressed by UST Program.

Site 31: Poverty Island Potential Mine Burial Site X No mine pit identified at the site.

No Restriction = No installation use restrictions placed on the site. Installation Residential Use Restriction = A residential use restriction prohibiting military family housing, childcare, daycare, schools, playgrounds, and non-military residential use is placed on the site in the Installation Master Plan. 2.13 STATUTORY DETERMINATIONS The remedial alternatives for the two former small arms range sites and the 15 LUC Sites were developed to achieve a completed response action for these sites in a streamlined fashion. To complete a streamlined response, EPA and MDE support the Selected Remedies as necessary

Land Use Control Sites: Sites 4, 5, 7, 10, 21, 28c, 28d, and 28e LUC Sites: Land Use

Control Boundaries

Figure 11

Land Use Control and No Further Action Sites: Sites 6, 11, 13, 14, 15, 18, 19, 22, 24, 28a, and 28b

Figure 12

LUC Sites: Land Use Control Boundaries

Land Use Control and No Further Action Sites: Sites 20, 27, and 31

Figure 13

LUC Sites: Land Use Control Boundaries

64

to adequately and cost-effectively protect human health and the environment. The Selected Remedies will meet the following statutory requirements of CERCLA 121 (b): to be protective of human health and the environment; to comply with ARARs; and to be cost-effective. The Selected Remedies do not employ treatment technologies to reduce toxicity, mobility, and volume of source material because of high cost and lack of performance advantage. The Selected Remedies utilize a permanent solution to the maximum extent practicable. The following sections discuss how the Selected Remedies meet these statutory requirements. 2.13.1 PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT The Selected Remedy for the two former small arms range sites (Alternative 6) will be protective of human health and the environment through UXO range clearance; excavation of soil impacted with antimony, arsenic, copper, lead, zinc; separation of particulate metal; stabilization of the excavated soil; offsite disposal of impacted soil; recycling/disposal of metal scrap; confirmation monitoring of the excavated areas; and implementation of LUCs. The Selected Remedy will meet the RGs. This alternative is a permanent remedy that addresses all COC-impacted soil. The complete removal of impacted soil removes potential risks to human health and ecological exposure risks. However, the extensive clearing and grubbing of vegetation, and the removal of soil will also likely destroy established habitats. Revegetation will eventually address the replacement of habitat. To protect workers, onsite activities will be conducted in accordance with OSHA requirements for workers at remedial sites (29 CFR Part 1910). Data from confirmation monitoring will verify whether the Selected Remedy was effective in attaining the RGs. LUCs will be implemented to ensure that the sites are not used for residential purposes. The Selected Remedy for the 15 LUC Sites (Alternative 2) will be protective of human health by preventing future military family housing, elementary and secondary schools, child care facilities, playgrounds, and non-military residential land use. The reported constituents do not pose unacceptable risk to ecological receptors. 2.13.2 COMPLIANCE WITH APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS There are no chemical-specific ARARs that govern the response action at the two former small arms range sites. The Selected Remedy will comply with location-specific ARARs regulating wetlands, flood plains, proximity to surface water, and ecological receptors. The Selected Remedy will also be conducted in compliance with action-specific ARARs related to soil removal, erosion and sediment control, dust emissions, hazardous an d non-hazardous waste disposal, OEW removal, and monitoring. Table 10 presents ARARs for the Selected Remedy. Federal and State regulations governing transportation of RCRA wastes offsite, which are applicable at the time that transportation takes place, must be complied with fully. There are no ARARs associated with the 15 LUC Sites.

65

Table 10: ARARs⎯Action/Location-Specific Applicable or Relevant and Appropriate Requirements are the Substantive Requirements found in the Following Regulations

Environmental Laws and Regulations

Action Status Consideration as an ARAR

Federal Action Specific ARARs RCRA Land Disposal Restrictions (LDRs)

(40 CFR 268)

Disposal of hazardous waste. Applicable Movement of excavated materials from their original location triggers the RCRA LDRs.

Maryland Action Specific ARARs – The following Maryland regulations which are more stringent than the corresponding federal regulations are ARARs

RCRA Identification and Listing Hazardous Waste

(COMAR 26.13.02.02-.15) (COMAR 26.13.02.18)

(COMAR 26.13.02.20-.22) (COMAR 26.13.02.26)

Waste generation from remediation of waste and

contaminated media.

Applicable Any waste media that are actively managed or shipped offsite must be tested to determine if they are

RCRA characteristic wastes.

Standards for Owners and Operators of TSD

Facilities (COMAR 26.13.05)

Transportation and disposal of hazardous wastes.

Applicable Soil piles could exhibit hazardous characteristics and may need to be

managed accordingly.

Erosion and Sediment Controls

(COMAR 26.17.01.02) (COMAR 26.17.01.07)

Remedial excavation/construction. Applicable Applicable to any soil cover or waste removal actions.

Control of Fugitive Particulate Matter

(COMAR 26.11.06.03) (COMAR 26.11.06.08)

Remedial excavation/construction. Applicable Applies to emission of particulates (dust) generated during excavation

or other remedial construction activities.

Maryland – Location Specific ARARs Non-Tidal Wetlands

COMAR 26.23.01-05 Remedial excavation/construction. Applicable

Applies to construction or management of property in

wetlands. 2.13.3 COST EFFECTIVENESS In the lead agency’s judgment, the Selected Remedies represent a reasonable value for the money to be spent. In making this determination, the following definition was used: “A remedy shall be cost-effective if its costs are proportional to its overall effectiveness.” [NCP Section 300.430(f)(l)(ii)(D)]. This was determined by evaluating the “overall effectiveness” of those alternatives that satisfied the threshold criteria (i.e., were both protective of human health and the environment and ARAR-compliant). Overall effectiveness was evaluated by assessing three of the five balancing criteria (long-term effectiveness and permanence; reduction in toxicity, mobility, and volume through treatment; and short-term effectiveness). Overall effectiveness of each alternative was compared and evaluated to determine cost-effectiveness. The estimated present worth cost of the Selected Remedy for the two former small arms range sites is $4,000,000. Alternative 4 was initially believed to be the most cost-effective based on other small-arms firing range remediation case studies. The estimated present worth cost for Alternative 4 was $2,785,000. However, during a Treatability Study for the soil washing process (Alternative 4), it was found that soil washing to concentrate the COCs to a smaller volume was

66

ineffective for the site-specific soils and would not reduce the volume of soil for offsite disposal. The Selected Remedy (Alternative 6) is a proven technology and it is the most cost-effective after removing Alternative 4 from consideration.. There is no cost associated with the 15 LUC Sites. The costs associated with the implementation and maintenance of the use restrictions for these will be incorporated with the implementation and maintenance for the Other Aberdeen Areas sites. 2.13.4 UTILIZATION OF PERMANENT SOLUTIONS AND ALTERNATIVE TREATMENT

TECHNOLOGIES (OR RESOURCE RECOVERY TECHNOLOGIES) TO THE MAXIMUM EXTENT PRACTICABLE

The Army and USEPA, in coordination with MDE, has determined that the Selected Remedy for the two former small arms range sites represents the maximum extent to which permanent solutions and treatment technologies can be utilized in a practicable manner at the Pistol Range and Known Distance Range. The Selected Remedy provides the best balance of trade-offs in terms of the five balancing criteria and considering State and community acceptance. The Selected Remedy addresses the materials constituting a risk to human health and the environment at the Pistol Range and Known Distance Range, through excavation, stabilization, and removal via offsite/off-Post disposal, achieving significant reduction in COCs in soil which satisfies the criteria for long-term effectiveness. The Selected Remedy does not present short-term risks different from the other alternatives. There are no special implementability issues that set the Selected Remedy apart from any of the other alternatives evaluated. The time required for mobilization and construction of the Selected Remedy is estimated to be approximately 12 months. 2.13.5 PREFERENCE FOR TREATMENT AS A PRINCIPAL ELEMENT The Selected Remedies do not utilize treatment as a principal element and, therefore, do not satisfy the statutory preference for treatment as a principal element. 2.13.6 FIVE-YEAR REVIEW REQUIREMENTS Contaminants may remain onsite above levels that allow for unlimited use and unrestricted exposure. Therefore, 5-year reviews will be performed for the two former small arms range sites and the 15 LUC Sites. 2.14 DOCUMENTATION OF SIGNIFICANT CHANGES FROM PREFERRED ALTERNATIVE IN THE

PROPOSED PLAN The Pistol Range, Known Distance Range, and 23 Other Sites Proposed Plan for Remedial Action (EA 2006c) identified Alternative 4 (Soil Washing) as the Preferred Alternative for the Pistol and Known Distance Ranges. Alternative 6, which involved soil stabilization prior to offsite disposal at a RCRA Subtitle D landfill, was also considered. After the comment period, new information indicated that the soil washing process could not reduce contaminants to safe

67

levels for human health and the environment that would allow the replacement of the soil onsite, and the majority of the excavated soil would require offsite disposal at a RCRA Subtitle C landfill. Therefore, the Army and the USEPA, with concurrence of the State, decided to select stabilizing the excavated impacted soil onsite and offsite disposal to a RCRA subtitle D landfill (Alternative 6) rather than using the soil washing.

68

3. RESPONSIVENESS SUMMARY The final component of the Record of Decision is the Responsiveness Summary. The purpose of the Responsiveness Summary is to provide a summary of the public’s comments, concerns, and questions about the two former small arms range sites and 23 Sites, and the Army’s responses to these concerns. APG held a public meeting on 21 September 2006 to formally present the Proposed Plan and cleanup actions and to answer questions and receive comments. The transcript of this meeting is part of the administrative record for this site. During the public comment period, APG also received written comments. The Army and USEPA have considered all comments and concerns, summarized below, in selecting the remedial alternative for the two former small arms range sites, and selecting the No Further Action determination at the 23 Sites. The Responsiveness Summary is divided into the following sections: 3.1 Overview. 3.2 Background on community involvement. 3.3 Summary of comments received during the public comment period and APG’s responses. A sample newspaper notice announcing the public comment period and the public meeting is presented in Appendix A. 3.1 OVERVIEW At the time of the public comment period, the Army had proposed the preferred alternative for the two former small arms range sites and the No Further Action determination for the 23 Sites, within the OAA. The preferred alternative for the two former small arms range sites included clearing removal areas of OEW, excavating areas of COC-impacted soil that exceed RGs for separation of metallic debris and soil washing prior to removing it off-Post and transporting it in accordance with applicable USDOT and RCRA regulations, to a regulated landfill. For the 23 Sites, no further action was proposed for the 8 NFA Sites and anticipated land use supported by Installation use restrictions to prohibit military family housing and non-military residential land use was proposed for the 15 LUC Sites. In view of the comments received, the Community generally accepted the proposed alternative for the two former small arms range sites (Alternative 4), a LUC remedy for the 15 LUC sites, and a No Further Action determination for the 8 sites. The public did not object to Alternative 6 (clearing removal areas of OEW, excavating areas of COC-impacted soil that exceed RGs for separation and stabilization prior to removing it off-Post to a regulated landfill as non-hazardous materials) as a potential remedial alternative as was presented in the September 2006 Proposed Plan.

69

3.2 BACKGROUND ON COMMUNITY INVOLVEMENT APG has maintained an active public involvement and information program for the Installation Restoration Program (IRP) since the early 1990s. Community members in Harford and Baltimore counties have actively participated in information sessions, tours, and public meetings, and APG staff has given briefings at community association meetings. APG’s community relations activities specifically related to the Pistol Range, Known Distance Range, and 23 Sites include the following:

• APG began discussing the Other Aberdeen Areas Pistol Range and Known Distance Range Phase II RI with the Restoration Advisory Board (RAB) in August 2002. Other Board meetings where APG presented information on these sites included September 2003 and September 2004.

• APG released the Pistol Range, Known Distance Range, and 23 Other Sites Proposed

Plan for public comment on 1 September 2006. 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 copy of the Proposed Plan also was posted on the IRP’s website, and the public was invited to comment through the website.

• A 45-day comment period on the Pistol Range, Known Distance Range, and 23 Other

Sites ran from 1 September to 15 October 2006. • APG prepared a news release announcing the availability of the Proposed Plan on

13 September 2006, 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 Avenue on Monday, 4 September 2006; The Cecil Whig and The Kent County News on Monday, 4 September 2006; and The Aegis on Friday, 1 September 2006.

• APG prepared and published a fact sheet on the Pistol Range, Known Distance Range,

and 23 Other Sites. On 14 September 2006, APG mailed copies of this fact sheet to approximately 2,300 citizens and elected officials on its IRP mailing list. The fact sheet included a form, which citizens could use to send APG their comments.

• On 21 September 2006, APG held a public meeting at the Aberdeen Senior Center in

Aberdeen, Maryland. Representatives of the Army, USEPA, and MDE were present. APG representatives presented information on the Pistol Range, Known Distance Range, and 23 Other Sites and on the proposed cleanup actions.

70

3.3 SUMMARY OF COMMENTS RECEIVED DURING THE PUBLIC COMMENT PERIOD AND ARMY RESPONSES

Comments raised during the public comment period on the Pistol Range, Known Distance Range and 23 Other Sites are summarized below. The comments are categorized by source. WRITTEN COMMENTS FROM PUBLIC MEETING As part of its fact sheets on the Proposed Plans, APG included a questionnaire that residents could return with their comments. APG received four forms. The alternatives preferred by individuals returning comment forms on the sites were: 0 Alternative No. 1 – Take No Action. 1 Alternative No. 2 – Land Use Controls 0 Alternative No. 3 – OEW Clearance, Excavation, Physical Separation, and

Offsite Disposal 2 Alternative No. 4 – OEW Clearance, Excavation, Soil Washing, and Offsite

Disposal 0 Alternative No. 5 – OEW Clearance, Excavation, Silica Stabilization, and

Offsite Disposal 0 Alternative No. 6 – OEW Clearance, Excavation, Soluble Phosphate

Stabilization, and Offsite Disposal 1 Have no preference Written comments included on the sites forms are summarized below. Comment No. 1: [Commenter selected Alternative 4] “Thank you for the opportunity to comment on the proposed actions. The Army has always kept local residents informed of its actions. As a nearby resident, I appreciate that very much.” Response No. 1: APG appreciates the feedback and will continue to keep the community informed and involved in its environmental cleanup program. Comment No. 2: [Commenter selected Alternative 2] “If #4 still has land use restrictions, why not go with #2?” Response No. 2: APG and the USEPA determined that Alternative 4 for the two range sites would be protective of human health and the environment after measuring each proposed alternative against the nine evaluation criteria. Alternative 2 would be protective of human health; however, this alternative does not address other metals that are co-located with the lead and identified as ecological COCs. Comment No. 3: [Commenter did not have a preference] “Due to my age and medical problems, I am not interested in any more literature from you in the future. Thank you for all the past information.”

71

Response No. 3: APG appreciates the past involvement and comments. Comment No. 4: [Commenter selected Alternative 4] “Having the areas being discuss for clean-up be highlighted on the aerial map.” Response No. 4: APG appreciates the suggestion and will present more effective visual aids during public presentations. ORAL COMMENTS FROM PUBLIC MEETING Comment No. 1: Why are the goals for the same metals different between the Pistol Range and the Known Distance Range? Response No. 4: The site-specific RGs for each COC were based on an evaluation of the calculated RGs for human health and ecological receptors. Therefore, the RGs for each compound could vary from site to site based on the anticipated ecological receptors. In general, the lowest calculated concentration for each COC, for either human or ecological receptors, was utilized as the RG, except where the RG was calculated to be below the established background concentration. In these instances, the background value was utilized for the RG.

72

4. REFERENCES Aberdeen Proving Ground (APG). 1981. Installation Assessment of Aberdeen Proving Ground-

Aberdeen Area, report prepared by Environmental Science and Engineering, Inc for USATHAMA, APG, Maryland, Report No. 301.

Aberdeen Proving Ground (APG). 1990. Draft RCRA Facility Assessment, Other Aberdeen

Areas, Aberdeen Proving Ground, Maryland. Report prepared by Derryberry et al., U.S. Army Corp of Engineers (USACE), Waterways Experiment Station (WES), Vicksburg, Mississippi for ECRD, APG, Maryland.

Aberdeen Proving Ground (APG). 1995. Data Summary Report for the Aberdeen Areas,

Sampling in Support of the Risk and Biological Impact Assessment of Aberdeen Proving Ground, Maryland. Report prepared by ICF Kaiser Engineers, Inc. Draft. June.

Aberdeen Proving Ground (APG). 2002. Baseline Ecological Risk Assessment of the Aberdeen

Area, Aberdeen Proving, Aberdeen Proving Ground Maryland. Report prepared by IT Corporation. Draft. September.

Battelle. 1997. Implementation Guidance Handbook, Physical Separation and Acid Leaching to

Process Small-Arms Range Soils. Prepared for Naval Facilities Engineering Service Center and US Army Environmental Center. Final. September.

Conley, J.H. 1997. Memos for Record, Subject: Block 5100 Pistol Range and Michaelsville

Known Distance Range dated 24 and 30 January 1997. Aberdeen Proving Ground, Maryland.

EA Engineering, Science, and Technology, Inc. (EA). 2005a. Phase II Remedial Investigation

Report – Volume II, Other Aberdeen Areas, Aberdeen Proving Ground, Maryland. February.

EA Engineering, Science, and Technology, Inc. (EA). 2005b. Baseline Human Health Risk

Assessment, Site 30a: Pistol Range and Site 30b: Known Distance Range, Aberdeen Areas, Aberdeen Proving Ground, Maryland. January.

EA Engineering, Science, and Technology, Inc. (EA). 2005c. Baseline Ecological Risk

Assessment, Site 30a: Pistol Range and Site 30b: Known Distance Range, Aberdeen Areas, Aberdeen Proving Ground, Maryland. February.

EA Engineering, Science, and Technology, Inc. (EA). 2005d. Feasibility Study for IRP Site

30A: Pistol Range and IRP Site 30B: Known Distance Range, Aberdeen Proving Ground, Maryland. June 2005.

73

EA Engineering, Science, and Technology, Inc. (EA). 2006a. Record of Decision: Six Groundwater Sites – Site 16: DRMO Metal Scrap Yard, Site 23: Building 525 Site, Site 28f: Building 3327 UST Site, Site 29: Tower Road Site, Site 32: Building 507 Site, Site 33: Building M600 Site, Aberdeen Areas, Aberdeen Proving Ground, Maryland. January 2006.

EA Engineering, Science, and Technology, Inc. (EA). 2006b. Record of Decision: Five

Sediment Sites – Site 8: Discarded Batteries at Abbey Point Navigation Light, Site 9: Discarded Batteries at Spesutie Island Navigation Light, Site 12: Old Chemical Dump on Spesutie Island, Site 16: DRMO Metal Scrap Yard, Site 17: Silver Contaminated Ditch in Transonic Range Area, Aberdeen Areas, Aberdeen Proving Ground, Maryland. March 2006.

EA Engineering, Science, and Technology, Inc. (EA). 2006c. Proposed Plan: Pistol Range,

Known Distance Range, and 23 Other Sites, Aberdeen Areas, Aberdeen Proving Ground, Maryland. August 2006. Final.

URS Corporation. 2002. Phase I Remedial Investigation Report, Other Aberdeen Areas,

Aberdeen Proving Ground, Maryland.

APPENDIX A

NEWSPAPER NOTICE

U.S. ARMY INVITES PUBLIC COMMENT

ON PROPOSED PLAN FOR THE PISTOL RANGE,

KNOWN DISTANCE RANGE AND 23 OTHER SITES

LOCATED IN THE ABERDEEN AREA OF APG

The U.S. Army at Aberdeen Proving Ground (APG) invites the public to comment on itsProposed Plan for the Pistol Range, Known Distance Range and 23 Other Sites within the

Other Aberdeen Areas Study Area, located in the Aberdeen Area of APG.

APG has prepared a fact sheet on the ProposedPlan that includes a comment form that can bereturned to APG. If you are not on APG'smailing list, you can request a copy of the factsheet by calling APG's 24-hour EnvironmentalInformation Line at (410) 272-8842 or(800) APG-9998.

APG invites the public to attend a meeting on:

Date: Thursday, September 21, 2006Time: 6:30 p.m. informal poster/

information session7:15 p.m. presentation

Place: Aberdeen Senior Center7 Franklin StreetAberdeen, MD 21001

The meeting location is wheelchair accessible,and an interpreter for the hearing impaired isavailable with 72-hours advance notice (call800-APG-9998).

APG is proposing to take action at the two sites listed below:

1. The Pistol Range is a former small arms firing range that is no longer operational. Metalcontamination is localized in surface soil; primary contaminants of concern are antimony, arsenic,copper, and lead.

2. The Known Distance Range is a former small arms firing range that is no longer operational. Metalcontamination is localized in surface soils; primary contaminants of concern are antimony, copper, lead,mercury, and zinc.

In addition to the two former small arms range sites requiring action (the Pistol Range and KnownDistance Range), the Proposed Plan also addresses 23 Other Aberdeen Area (OAA) sites which warrantNo Further Action (NFA) based on the results of the Remedial Investigations and risk screening. The 23Sites are listed below:

The 45-day public comment period on the proposedaction extends from 1 September through 15October 2006. Written comments, postmarked byOctober 15, should be sent to:

Directorate of Safety, Health & EnvironmentATTN: IMNE-APG-SHE-RBuilding E5771 Magnolia RoadAberdeen Proving Ground, MD 21010; or

U.S. Environmental Protection Agency1650 Arch Street (3HS11)Philadelphia, PA 19103; or

Maryland Department of the EnvironmentFederal Facilities Division1800 Washington Boulevard, Suite 645Baltimore, MD 21230.

Mr. Ken Stachiw, Program Manager

Mr. Frank Vavra

Ms. Peg Nemoff

You can review the Proposed Plan and providecomments through the APG Web Site atwww.apg.army.mil. Click on Directorates; Safety,Health and Environment; EnvironmentalConservation and Restoration Division.

FACT SHEET

PUBLIC MEETING

WRITTEN COMMENTS

PROPOSED ACTION

WEB SITE

ALTERNATIVES EVALUATED FORTHE PISTOL RANGE AND KNOWN DISTANCE RANGE

Six alternatives were evaluated for the Pistol Range and Known Distance Range. These include:

.

Based on an analysis of the alternatives, APG prefers Alternative 4 for the Pistol Range and KnownDistance Range.

The preferred alternatives may be modified or new alternatives may be developed based on public input.The final alternatives selected will be documented in a Record of Decision that summarizes the decision-making process. APG will summarize and respond to comments received during the comment period aspart of the Record of Decision. Copies of the Feasibility Study and the Proposed Plan are available forreview at the APG information repositories. The repositories are located at the Edgewood and Aberdeenbranches of Harford County Library and Miller Library at Washington College in Kent County.

Alternative 1: No ActionAlternative 2: Land Use Controls (LUCs).Alternative 3: Excavation and Disposal and LUCs.Alternative 4: Soil Washing and LUCs.Alternative 5: Encapsulation and LUCs.Alternative 6: Stabilization and LUCs.

No alternatives were evaluated for the 23 OAA Sites because no action is proposed at these sites due tothe reasonably anticipated industrial/military land use at these sites. Use restrictions will be implementedat 15 of the 23 Sites to restrict future residential use.

� Site 3: Churchville Test Course Dump � Site 20: Potential Explosives in Groundwater Area

� Site 4: Outdoor Pesticide Mixing Area at Bldg 5010 � Site 21: POL Facility Sand Pit Near Bldg 5215

� Site 5: DPW Backyard Storage Area Near Bldg 5262 � Site 22: Bldgs 309 and 390 Storm Sewer Outfalls

� Site 6: DDT Spill Near Bldg 450 � Site 24: White Phosphorous Munitions Land Burial Area

� Site 7: Spent Lead Acid Battery Site Near Bldg 2351 � Site 27: German Ammunition Train Explosion Area

� Site 10: Bldg 5039 Battery Shop � Site 28a: Bldg 436 UST Site

� Site 11: Old Burn Trench on Spesutie Island � Site 28b: Bldg 456 AST Site

� Site 13: Chemical Dump Ponds on Spesutie Island � Site 28c: Bldg 2458 UST Site

� Site 14: Former Burning Area Near Bldg 1171 � Site 28d: Bldg 3329 UST Site

� Site 15: Metal Barricade Near Bldg 1122 � Site 28e: Bldg 3505 UST Site

� Site 18: Barrels Near Bldg 510 � Site 31: Poverty Island Potential Mine Burial Site

� Site 19: Sandblast Area Near Bldg 523