department of the army us army installation … · mr. robert stroud npl/brac/federal ... landfill...

May 16, 2017

Environmental Division

Mr. Robert Stroud NPL/BRAC/Federal Facilities Branch U.S. Environmental Protection Agency 701 Mapes Road Fort Meade, Maryland 20755

Dear Mr. Stroud:

Enclosed please find the Final Proposed Plan (Plan) for the Closed Sanitary Landfill, (FGGM-17), Fort George G. Meade, Maryland. This Plan incorporates comments provided on the Draft Final Plan by the U.S. Environmental Protection Agency (USEPA) on March 29, 2017; May 1, 2017; and May 10, 2017.

Copies of the Plan have been furnished to Ed Carlson and Elisabeth Green (Maryland Department of the Environment), Timothy Peck (Baltimore District, Army Corps of Engineers), Fran Coulters (U.S. Army Environmental Command), and the Fort George G. Meade Restoration Advisory Board.

If you have any questions, please feel free to contact Ms. Denise Tegtmeyer at (301) 677-9559 or me at (301) 677-7999.

Sincerely,

George B. Knight, PG Program Manager, Installation Restoration Program Directorate of Public Works-Environmental Division

Enclosure

DEPARTMENT OF THE ARMY US ARMY INSTALLATION MANAGEMENT COMMAND HEADQUARTERS, UNITED STATES ARMY GARRISON

4551 LLEWELLYN AVENUE, Suite 5000 FORT GEORGE G. MEADE, MARYLAND 20755-5000

Final 1 Proposed Plan May 2017 The Closed Sanitary Landfill (FGGM-17) Fort George G. Meade, Maryland

INTRODUCTION AND PURPOSE

This Proposed Plan (PP) provides information necessary to allow the public to participate with the United States (U.S.) Department of the Army (Army), the Lead Agency, and the U.S. Environmental Protection Agency (USEPA) Region III, the lead regulatory agency, in the remedy selection process for three locations within the “Closed Sanitary Landfill” (CSL) area (FGGM-17) (“the Site”), located in the southeastern portion of Fort George G. Meade (FGGM), Maryland, south of State Route 32 and west of the Amtrak railroad right of way (Figure 1). The first two locations associated with the CSL Site are landfill Cells 1 and 2. The third location addressed in this PP is the Former Ammunition Supply Point (ASP) No. 1 (FGGM-08) which is located in the area north of landfill Cell 1 and west of landfill Cell 2. ASP No. 1 consisted of six magazines and associated access roads. The magazines were demolished in 2001. The location of a third area that lacks topographic expression is referred to as Cell 3. The locations of the three Cells and ASP No. 1 within the CSL boundary are shown on Figure 2.

The Remedial Alternative (RA) presented in this PP will address the human health impacts associated with Cells 1 and 2. Cell 3 will be addressed in a future Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) action, which will also fully examine and address any ecological environmental impacts presented by contaminants present at the entire CSL Site. Exceedances of Maximum Contaminant Levels (MCLs), promulgated under Section 1412 of the Safe Drinking Water Act, 42 U.S.C. § 300g-1, in Upper Patapsco Groundwater associated with landfill Cells 1 and 2 along the southeast FGGM installation boundary are driving the remedies detailed in this PP. The preferred RA described in this PP FGGM-17 is Air Sparging, Land Use Controls (LUCs), and Long-term Monitoring (LTM) of Groundwater. Based on the human health risk assessment (HHRA) completed during the RI (EM Federal, 2007), there are no unacceptable risks associated with ASP No. 1; therefore, no action will be taken for the ASP No. 1 area of the CSL site.

Throughout this document, figure and table references are bolded. In addition, bolded terms are defined in the Glossary Section.

The environmental cleanup activities at FGGM are conducted pursuant to CERCLA, as amended, 42 U.S.C. §§ 9601 – 9675, and the National Oil and Hazardous Substances Pollution Contingency Plan (NCP) [40 Code of Federal Regulations (CFR) 300]. FGGM was placed on the National Priorities List (NPL) on July 28, 1998. The Army coordinates cleanup activities with the

USEPA Region III, and, as appropriate, the other signatories of the FGGM Federal Facility Agreement (FFA), including the Architect of the Capitol and the Department of the Interior. The Army also solicits input from the Maryland Department of the Environment (MDE).

This PP summarizes information found in detail in the Remedial Investigation (RI) (EM Federal Engineering, 2007) and the Focused Feasibility Study (FFS)/Assessment of Corrective Measures (ACM) (Arcadis, 2014a) as well as other reports that are available for review as part of the Administrative Record file for this site. This PP highlights the preferred RA for the remediation of groundwater in the Upper Patapsco Aquifer (UPA) at the Site and outlines all RAs identified during the FFS/ACM (Arcadis, 2014a).

Because Cells 1 and 2 of the CSL were part of an active landfill that was closed under Code of Maryland Regulation (COMAR) 26.04.07.21, the MDE Land Management Administration, Solid Waste Program has been overseeing post-closure care for the CSL under the State’s ongoing solid waste program approved by USEPA under the Resource Conservation and Recovery Act (RCRA). Post-closure care conducted at the Site includes semi-annual groundwater monitoring, landfill cap maintenance, and weekly methane monitoring. When FGGM was listed on the NPL in 1998, the CSL was included and investigation and restoration activities at the Site have been governed under the CERCLA program since that time. Ongoing post-closure monitoring activities administered by the MDE Solid Waste Operations Division have been separate and distinct from the FFA/CERCLA responsibilities. The FFS/ACM (Arcadis, 2014a) was performed in accordance with the requirements of CERCLA for the FFS and the MDE Solid Waste Program requirements, which use 40 CFR 258.56 to guide the performance of an ACM. The FFS/ACM (Arcadis, 2014a) evaluated performance criteria for the RAs considering both 40 CFR 258.56 for completing an ACM and Section 300.430(e)(iii) of the NCP regarding the conduct of a Feasibility Study (FS) to satisfy both regulatory programs (CERCLA and the MDE Solid Waste Program). However, going forward, the corrective action measures evaluated and implemented at the CSL will be performed in accordance with CERCLA and the FFA. Semi-annual groundwater monitoring would be a necessary component of the CERCLA remedy at the Site and would also comply with the MDE Solid Waste Program requirements for groundwater monitoring, and COMAR 26.04.07.22. The actions implemented under the preferred RA would also comply with the substantive requirements of applicable or relevant and appropriate State of Maryland regulations, which are also action-specific Applicable or relevant and Appropriate

FINAL PROPOSED PLAN FOR CLOSED SANITARY LANDFILL (FGGM-17)

FORT GEORGE G. MEADE, MARYLAND

May 2017


Requirements (ARARs), as described, below, in the Summary of the Preferred Remedial Alternative Section.

The Army and USEPA will finalize and present the selected RA for the Site in a Record of Decision (ROD). The final selection will not take place until after the public comment period. All significant comments will be considered and responded to in the Responsiveness Summary section of the ROD. The public is encouraged to comment on the preferred RA presented in this PP as well as the other RAs considered. Information about how to submit comments may be found in the “Community Participation” section of this PP.

The Army at FGGM and USEPA jointly issue this PP, with support from the MDE, to fulfill the public participation requirements of Section 117(a) of CERCLA, as amended, and the NCP Section 300.430(f)(3). The Army, USEPA, and MDE encourage the public to review all of the documents relevant to activities conducted at the Site in order to assist in the selection of an appropriate RA for the Site. Pertinent information regarding the public meeting and comment period is provided in the “Important Dates and Locations” table that follows.

IMPORTANT DATES AND LOCATIONS

Public Meeting: May 18, 2017

The Army will hold a public meeting to explain the PP and all Response Actions presented in the FFS/ACM following the Restoration Advisory Board meeting on May 18, 2017. Oral and written comments will also be accepted at the meeting. The meeting will be held at Marriott Courtyard, 2700 Hercules Road, Annapolis Junction, Maryland at 7 PM. Public Comment Period: May 18 – June 17, 2017

The Army will accept written comments on the PP during the public comment period. The Administrative Record, containing information used for the selection of the Response Action, is available for public review at the following location:

Anne Arundel County Public Library

Odenton Regional Branch 1325 Annapolis Rd.

Odenton, Maryland 21113 Additional information is maintained at the following location:

Fort Meade Environmental Division Office Building 2460, 85th Medical Battalion Ave.

Fort Meade, Maryland 20755

Remedial Alternatives

Remedial Alternative GW-1: No Action.

Remedial Alternative GW-2: Monitored Natural

Attenuation and Land Use Controls (LUCs).

Remedial Alternative GW-3: Air Sparging, LUCs, and

Long-term Monitoring (LTM) of Groundwater.

Remedial Alternative GW-4: Permeable Reactive

Barrier, LUCs, and LTM of Groundwater.

Relevant documents used in the preparation of this PP are listed in the “References” section found at the end of this document.

The results of the RI and Human Health Risk Assessment (HHRA) (EM Federal Engineering, 2007) indicate that surface/sub-surface soil, sediment, and surface water media from FGGM-17 do not present unacceptable risk to human receptors on- and off-site under current and future land use scenarios. Although extensive sampling of soil, surface water, and sediment performed to date does not indicate that the Site is causing adverse ecological impacts, an ecological risk assessment has not been completed for the CSL. The ecological risk assessment for the entire CSL Site, including the areas addressed by this action, will be performed in support of the remedy selection process for Cell 3.

Extensive investigations including the RI (EM Federal, 2007) support that the Upper Patapsco (water table) and Lower Patapsco (confined) aquifers are hydraulically unrelated and have demonstrated that FGGM-17 is not the source of carbon tetrachloride, trichloroethene, and tetrachloroethene contamination historically detected in the Lower Patapsco Aquifer (LPA). As a result, the LPA is being addressed under a separate CERCLA Operable Unit, designated as OU-4, and will be the subject of a separate CERCLA decision document, and it will not be addressed by the RA selected for the CSL. Only human health risks associated with the CSL and presented from groundwater in the UPA will be addressed through selection of one of the remedial alternatives presented in this PP.

The preferred RA presented in this PP addresses current MCL exceedances associated with Cells 1 and 2 along the FGGM southeast installation boundary for constituents in groundwater observed in the UPA on- and off-post.

SITE BACKGROUND

FGGM is located approximately midway between Washington, D.C. and Baltimore, Maryland, in Anne Arundel County, Maryland, as illustrated on the regional inset map in Figure 1. FGGM became an Army installation in 1917 and encompassed 9,349 acres. During World War I (WWI), over 100,000 soldiers passed


through FGGM. The 11th, 79th, and 92nd Infantry Divisions trained at the installation, and an Ordnance Supply School was established in 1918. When the war ended, FGGM served as a demobilization center for returning troops. FGGM became a permanent Army installation after WWI.

By 1940, there were 251 permanent and 218 temporary buildings and over 2,100 enlisted soldiers on-post. By December 1941, the total land acquired by FGGM had grown to approximately 13,800 acres. After World War II, the National Security Agency relocated to FGGM, and Tipton Airfield was constructed in 1960. In 1988, FGGM was realigned under the first round of Base Realignment and Closure (BRAC). The BRAC program authorized 9,000 acres to be divested from FGGM. The Army retained 900 acres of the BRAC parcel which included Tipton Airfield, which was later transferred to Anne Arundel County in 1999. As a result of the 1988 BRAC realignment and subsequent transfer of the Tipton Airfield, the installation includes approximately 5,145 acres. The current installation boundaries encompass the area previously referred to as the cantonment area, which is used for administrative, recreational, and housing facilities. FGGM contains approximately 65.5 miles of paved roads, 3.3 miles of secondary roads, and about 1,300 buildings. The USEPA placed FGGM on the NPL on July 22, 1998, after an evaluation of contamination due to past storage and disposal of hazardous substances. The FFA was signed by all parties involved in June 2009, which brought the prospective corrective action work under CERCLA authority.

Closed Sanitary Landfill (FGGM-17) History

As reported in the RI (EM Federal, 2007), the landfill began operation at FGGM in 1958, using the trench fill method until 1976 for disposal of “mixed residential, commercial, and non-hazardous industrial wastes.” The landfill was constructed as an unlined facility and was initially designated as the Active Sanitary Landfill and was divided into Cell 1 and Cell 2. Historical aerial photographs from 1970, 1975, and 1986 show the progression of expansion and waste disposal at the Site when the landfill was active. A third area that lacks topographic expression is referred to as Cell 3. The RAs presented in this PP will address the current MCL exceedances in UPA groundwater along the southeast FGGM installation boundary associated with Cells 1 and 2. Cell 3 will be addressed in a future CERCLA action, at which time the ecological environmental impacts of the contamination present at the entire CSL will also be fully examined and addressed. This PP also includes ASP No. 1 (FGGM-08) which was located in the area north of Cell 1 and west of Cell 2. ASP No. 1 consisted of six magazines and associated access roads located north of Cell 1 and west of Cell 2. The magazines were demolished in 2001. Based on the results of the HHRA completed during the RI (EM Federal, 2007), there are no unacceptable risks associated with ASP No. 1; therefore, no action will be taken for the ASP No. 1 area of the CSL site.

FGGM was issued a Refuse Disposal Permit (Permit No. 80-02-00-08-A) in 1980 by the Maryland Department of Health and Mental Hygiene (now MDE). In 1992, FGGM was issued a Refuse Disposal Permit by MDE (Permit No. 1992-WSF-0022-0) to continue operation of the sanitary landfill. This permit was renewed in 1995 and expired in 2000. Thereafter, it was not renewed. A federal/state mandated detection monitoring program was initiated in March 1994, and is reflected in the 1995 permit, to identify potential deficiencies in the landfill operation. Based on the results of the detection monitoring, assessment monitoring was initiated for the UPA in November 1994 and was initiated for the LPA in June 2000. Under the monitoring program, groundwater and surface water samples are collected and analyzed on a semi-annual basis.

In 1996, operations at the sanitary waste landfill ceased. Since that time, the MDE Division of Solid Waste has been administering post-closure care under COMAR 26.04.07.22.

Current and Future Use

Landfill closure activities at FGGM-17 were conducted under the State’s Solid Waste Program authority from 1995 through 1998. Landfill Cell 1 was capped and closed from 1995 through 1997, and Landfill Cell 2 was capped and closed during 1997 and 1998. A flexible membrane liner was incorporated into the final cap system for both Landfill Cells 1 and 2. Landfill Cell 3 is not a defined disposal area and was not capped and was not included in the Solid Waste Program permit. Semi-annual groundwater monitoring has been ongoing and a landfill-gas collection and treatment system operates along the eastern edge of the landfill cells to control emissions from the Site. Issues strictly associated with the landfill itself (post-closure care and groundwater quality issues from operations) have been handled under the MDE Solid Waste Program authority to date. At present, the planned future use of the Site is recreational/training (Atkins, 2011). Groundwater is currently not used at the Site and all remedial alternatives presented in subsequent sections of this PP would include an on-post groundwater use restriction and adherence to groundwater use restrictions in off-post areas administered by the Anne Arundel County Health Department (County) until such time that contaminants in groundwater are at levels that allow for unlimited use and unrestricted exposure.

Historical Investigations

A groundwater monitoring program for the UPA (water table aquifer) and LPA (confined aquifer) was conducted as part of the MDE Solid Waste Program closure to ensure that leachate from the landfill did not impact groundwater. Groundwater in the UPA and LPA are separated by a confining geologic layer, the Middle Patapsco Clay unit. As extensive investigations have demonstrated, the two aquifers are hydraulically unrelated (EM Federal, 2007); the LPA is being addressed under a separate CERCLA Operable Unit (OU-4) and will not be addressed by the RA selected for


the Site. Therefore, investigations related to the LPA are not discussed herein.

The RI for the Site was conducted from 2001 to 2004. Soil, sediment, groundwater, and surface water data collected during the RI were used to complete the HHRA (EM Federal, 2007). The RI effort included the collection of eighteen shallow sub-surface samples collected in Cell 3 and at the Former ASP No. 1 to assess potential soil contamination, characterize landfill material, and evaluate potential risk. The results of the HHRA confirmed that there are no unacceptable risks associated with ASP No. 1. ASP No. 1 was demolished and removed in 2001 and no further action in necessary at ASP No. 1. As previously mentioned, Cell 3 will be addressed in a future CERCLA action. The HHRA and follow up supplemental risk evaluation conducted as part of the FFS/ACM (Arcadis, 2014a) concluded that there are no unacceptable risks to human health associated with soil, sediment, and surface water media at the CSL. Therefore, groundwater in the UPA is the only impacted medium being addressed in this PP, and soil, sediment, and surface water will not be discussed further. Although extensive sampling of soil, surface water, and sediment performed to date does not indicate that the Site is causing adverse ecological impacts, an ecological risk assessment has not been completed for the CSL. The ecological risk assessment for the entire CSL Site, including the areas addressed by this action, will be performed in support of the remedy selection process for Cell 3. Analytical results and sampling methodology from the RI are presented in the RI Report (EM Federal, 2007).

Supplemental groundwater monitoring activities occurred in 2013 and 2014, including off-post plume delineation activities. The off-post plume delineation, which included UPA groundwater samples collected from both monitoring wells and borings using direct-push technology (DPT), confirmed off-post detections of arsenic above its MCL of 10 micrograms per liter (µg/L) in the UPA. A supplemental risk evaluation was completed as part of the FFS/ACM (Arcadis, 2014a). The supplemental risk evaluation included current UPA groundwater conditions on- and off-post using the data representing samples collected from monitoring wells. The supplemental risk evaluation was conducted by comparing current groundwater exposure point concentrations (EPCs) to those used by the USEPA in their 2009 comments on the Final RI (EM Federal, 2007). The benzene, toluene, ethylbenzene, xylene, and arsenic data from groundwater samples collected off-post using DPT was not used in the supplemental evaluation of risk. However, it is noted that the detected concentrations of arsenic in DPT groundwater samples are comparable to those detected in samples obtained from off-post monitoring wells. Benzene, which was not detected in any off-post monitoring well samples collected in 2013, was detected in DPT samples at lower concentrations than those generally observed in on-post groundwater samples collected in 2013. It is noted that all the DPT samples were collected at off-post locations

immediately downgradient of the FGGM property boundary.

A summary of the supplemental evaluation is presented in the FFS/ACM (Arcadis, 2014a). The evaluation of recent (2013) groundwater data was conducted using risk evaluation methodologies similar to those used in 2007 and 2009 to assess the risk posed by potential exposure of hypothetical adult and child residents to on-post and off-post UPA groundwater. The revised risk estimates indicate that total arsenic concentrations in on-post UPA groundwater pose an unacceptable carcinogenic risk (9.7E-04) based on future potential use as a drinking water resource. The revised hazard estimates associated with future exposure of hypothetical adult and child residents to on-post UPA groundwater exceed the hazard index (HI) threshold of 1, with arsenic, iron, and manganese contributing the majority of the excess hazard (see inset box on Page 6 for the explanation of the carcinogenic risk notation and non-cancer HI).

During groundwater monitoring events completed in 2013, identified MCL exceedances included arsenic, benzene, and nitrate in groundwater samples from the UPA. These constituents will be addressed as part of the preferred RA in addition to those constituents identified as risk drivers (arsenic, iron, and manganese) under potential land-use scenarios in UPA groundwater.

SITE CHARACTERISTICS

Closed Sanitary Landfill (FGGM-17) Description

FGGM-17 is located in the southeastern portion of the base, south of State Route 32 and northwest of the Amtrak railroad right of way. Cell 1 covers approximately 46 acres, and Cell 2 covers 24 acres. A third area that lacks topographic expression is referred to as Cell 3. ASP No. 1, which was located in the area north of landfill Cell 1 and west of landfill Cell 2, consisted of six magazines and associated access roads; however, the magazines were demolished in 2001 and only the access roads remain. Other features in the vicinity of the landfill include surface water retention ponds along a small stream flowing from east to west that bisects the Site. A landfill-gas collection and treatment system operates along the eastern edge of the landfill cells to control emissions from the Site. Much of the Site, outside of the landfill cells, is wooded and there are several areas identified as wetlands. The site map for FGGM-17 is provided as Figure 2.

Extent of Contamination in Groundwater

The extent of contamination in groundwater at the Site has been investigated both through the ongoing semi-annual groundwater monitoring conducted pursuant to MDE’s Solid Waste Program requirements and the MDE Refuse Disposal Permit since 1994, and through the RI activities conducted under CERCLA, beginning in 2002.

The MDE Solid Waste Program monitoring program for the CSL includes 26 monitoring wells. The MDE Solid Waste Program monitoring program was initiated at the


CSL in 1994 and is on-going. The MDE Solid Waste Program monitoring program has been revised numerous times since its inception; however, the current program includes 16 monitoring wells screened in the UPA sampled semi-annually and ten monitoring wells screened in the LPA sampled annually. As previously mentioned, the LPA will not be addressed under the FGGM-17 CERCLA action detailed in the PP; rather a separate CERCLA action is underway for OU-4 which will address deep groundwater contamination in the LPA. MCL exceedances observed during the September 2013 event in the UPA are summarized in the following section. Site-related MCL exceedances were isolated and include only arsenic, benzene, and nitrate.

• Arsenic exceeded its MCL of 10 µg/L in three samples at concentrations between 39 µg/L (MW-19) and 270 µg/L (MW-12S). The arsenic detection at MW-12S is a historical maximum. MW-12S was resampled in February 2014, and the total arsenic concentration was 61 µg/L at that time which is consistent with more recent historical data collected prior to 2013.

• Benzene exceeded its MCL of 5 µg/L in the sample from MW-19 (10 µg/L).

• Nitrate exceeded its MCL of 10 mg/L in the samples from MW-12S (17 mg/L) and MW13S (29 mg/L).

Although chromium exceeded its MCL of 100 µg/L in the September 2013 groundwater sample from MW-14 (270 µg/L), this sample result is not representative of groundwater conditions due to the presence of soil particulates evidenced by very high turbidity field measurements (789 NTU). Prior to the sampling event completed in September 2013, chromium was not detected in groundwater above its MCL at this location during any of the 39 semi-annual sampling rounds dating back to 1994 nor was it detected in the subsequent August 2014 semi-annual groundwater sampling event at this or any other monitoring well location. Therefore, the September 2013 results at MW-14 are not considered representative of groundwater conditions. With the exception of the September 2013 sampling event at MW-14 as discussed above, current groundwater data (September 2013) collected as part of the MDE Solid Waste Program monitoring program are comparable to historical groundwater data collected including data collected during the RI program initiated in 2002 used to complete the HHRA (EM Federal, 2007). Arsenic, benzene and nitrate were detected in samples from the UPA at concentrations exceeding their MCLs during the September 2013 event, as well as previously. The persistent MCL exceedances for arsenic benzene, and nitrate are observed primarily in wells south of landfill Cell 1 and in wells located between the cells and the Amtrak right of way. Further, statistical trend analysis completed as part of the semi-annual MDE Solid Waste Program monitoring program suggests that constituent of concern (COC) concentrations are not increasing.

Additional plume delineation activities were conducted in April 2013 and March 2014 during the FFS/ACM on- and off-post to complete delineation of arsenic and benzene detected above their respective MCLs from monitoring wells located southeast of Cell 1 near the FGGM property boundary. MCL exceedances observed during the supplemental plume delineation activities are discussed below. Sampling methodology and analytical results from the investigations are provided in the FFS/ACM (Arcadis, 2014a).

• Arsenic (total) was detected above its MCL of 10 µg/L in five samples:

o MW-19A (46 µg/L in March 2013) and (51 µg/L in June 2013) located on-post

o SB-02 collected from 28 – 33 feet (ft) below ground surface (bgs) (44 µg/L) and SB-02 collected from 34 – 39 ft bgs (44 µg/L)

o SB-06 collected from 28 – 33 ft bgs (31 µg/L).

• Arsenic (dissolved fraction) was detected above its MCL in six samples:

o MW-19A (47 µg/L in April 2013) and (53 µg/L in June 2013)

o SB-01 collected from 36-41 ft bgs (12 µg/L). At SB-01 dissolved arsenic only exceeded its MCL by 2 µg/L in the shallow groundwater sample and arsenic concentrations in the deeper groundwater sample collected at SB-01 were below the MCL.

o SB-02 collected from 28 – 33 ft bgs (40 µg/L) and SB-02 collected from 34 – 39 ft bgs (47 µg/L)

o SB-06 collected from 28 – 33 ft bgs (31 µg/L).

Total arsenic concentrations are displayed on Figure 3.

• Benzene was detected above its MCL of 5 µg/L in the sample collected from MW-19A (8.6 µg/L in March 2013 and 7.6 µg/L in June 2013) located on-post. Benzene was not detected above its MCL in any of the ten DPT groundwater samples collected off-post in April 2013. Benzene concentrations from June 2013 are displayed on Figure 3.

SCOPE AND ROLE OF THE RESPONSE ACTION

This response action presents the strategy for remediation at the Site, including UPA groundwater associated with landfill Cells 1 and Cell 2. As previously mentioned, the HHRA completed during the RI (EM Federal, 2007), determined there are no unacceptable risks associated with ASP No. 1; therefore, no action will be taken for the ASP No. 1 area of the CSL Site. The Site


is one of many sites at FGGM that are in the CERCLA process. The Site Management Plan (Stell, 2014) provides details on other sites at FGGM that will be addressed in separate response actions. The anticipated schedule for each site is also provided in the Site Management Plan.

Based on historical investigations, unacceptable risks were determined for future hypothetical residential land use scenarios due to exposure to contaminants in UPA groundwater at the Site. Use of the FGGM-17 for residential purposes is not a reasonably anticipated future land use and there are no plans to develop the site for residential use, and the presence of landfill caps would preclude that use. However, remedial action is necessary to address MCL exceedances in UPA groundwater associated with Cells 1 and 2 along the FGGM southeast installation boundary, both on- and off-post.

This PP provides a summary of the RAs considered for groundwater in the UPA at the Site and recommends the preferred RA (Remedial Alternative GW-3 – Air Sparging, LUCs, and LTM of Groundwater).

SUMMARY OF THE SITE RISKS

As presented in the supplemental risk evaluation in the FFS/ACM (Arcadis, 2014a), a risk assessment was conducted to determine the current and future effects of contaminants on human health.

The baseline HHRA estimates the level of risk the site poses to human health if no action is taken to address on-site contamination. As part of the baseline risk assessment, an HHRA was performed to identify constituents of potential concern (COPCs) at the Site to be evaluated as part of a cancer risk and non-carcinogenic hazard evaluation. Surface soils (0 to 2 ft bgs) and indoor air exposure were evaluated to assess current potential exposures associated with accessible soils at the Site. Surface/subsurface soils (0 to 10 ft bgs), groundwater, and indoor air exposure were evaluated to assess potential future exposures associated with direct contact by humans.

For the purposes of the screening evaluation, constituents were identified as COPCs when: soil maximum concentrations exceeded the USEPA Risk-Based Concentrations; groundwater maximum concentrations exceeded the MCLs; sediment maximum concentrations exceeded the Effects Range-Low; and surface water maximum concentrations exceeded the Ambient Water Quality Criteria. Those risk-based screening levels that were based on non-cancer endpoints were divided by 10 to adjust from the threshold hazard quotient (HQ) of 1 to 0.1 for identification of COPCs. If a constituent’s maximum concentration did not exceed its screening value, then that constituent was excluded from the risk assessment. Details of the HHRA methodology are presented in the RI Report (EM Federal, 2007). As previously mentioned, a supplemental risk evaluation was completed as part of the FFS/ACM (Arcadis, 2014a). The supplemental risk evaluation included current UPA

groundwater conditions on- and off-post using the data derived from samples collected from monitoring wells. The supplemental risk evaluation was conducted by comparing current groundwater EPCs to those used by USEPA in their 2009 comments on the Final RI (EM Federal, 2007).

Human Health Risk Assessment

As presented in the RI Report (EM Federal, 2007), an assessment was completed to identify COPCs at or derived from the Site to be quantitatively evaluated as part of an HHRA and hazard evaluation. The HHRA was completed in accordance with 40 CFR 300.430(d)(4) and USEPA guidance (USEPA, 1991). In 2009, USEPA commented on the HHRA presented in the RI Report (EM Federal, 2007). USEPA generated revised risk and hazard estimates based in part on changes in risk assessment practices between 2007 and 2009. The revised 2009 risk and hazard estimates as provided by USEPA reflect current and future site risks and hazards. As part of the FFS/ACM (Arcadis, 2014a), a supplemental risk evaluation was completed using groundwater data from 2013 to evaluate risks posed to human health from UPA groundwater under current conditions. Potential risks associated with exposure to chemicals in soil, sediment, groundwater, and surface water were evaluated for the following populations:

• Current on-post maintenance workers

• Current on-post trespassers

• Future on-post and off-post construction workers

• Future on-post and off-post adult and child residents

• Future on-post groundskeepers, club house workers, and golfers

On-post worker and trespasser exposures were assumed to be the same under future land-use conditions as those under current land-use conditions. The scenarios for groundskeepers, club house workers, and golfers were evaluated because of potential plans to convert the Site to a golf course at the time of the RI evaluation. At present, the planned future use of the Site is recreational/training (Atkins, 2011).


Although there are no plans for residential use of the land at the Site in the foreseeable future, the risks associated with future potential residential exposure scenarios (ingestion of, dermal contact with, and inhalation of groundwater) were also quantified in the HHRA. Details of the HHRA methodology are presented in the RI (EM Federal, 2007) and supplemental risk evaluation completed during the FFS/ACM (Arcadis, 2014a).

Potential exposure of off-post residents to groundwater in the LPA was also evaluated in the HHRA completed during the RI (EM Federal, 2007). However, as previously mentioned, extensive and on-going hydrogeological investigations in the southeast corner of FGGM have demonstrated that the Middle Patapsco Clay separates the UPA and LPA and is an effective confining unit. These investigations also determined that the CSL is not the source of groundwater contamination in the LPA. Contamination in the LPA is now being addressed under a separate CERCLA Operable Unit (OU-4). Therefore, risks associated with exposure to groundwater from the LPA are not discussed in this PP.

Results of the HHRA

No unacceptable risks were identified during the HHRA/supplemental risk evaluation for the following scenarios: current on-post maintenance workers; current on-post trespassers; future on-post and off-post construction workers; and future on-post groundskeepers, club house workers, and golfers. Unacceptable risks associated with the hypothetical future residential scenario are summarized below:

On-post Risk Summary

Hypothetical Residential Future Land-Use Scenario

Potential exposures to on-post soils, surface water, sediment, and groundwater by future hypothetical adult and child residents were evaluated. In addition, risk and hazard estimates were revised based on more recent UPA groundwater data. The conclusions of the USEPA’s 2009 comments on the HHRA presented in the 2007 RI were that the total upper-bound excess lifetime cancer risks associated with potential exposure of an on-post lifetime resident to COPCs in UPA groundwater exceeded the USEPA acceptable risk range. The primary contributor was arsenic (via the ingestion exposure pathway). The HI associated with potential exposure of an on-post adult resident to non-carcinogenic COPCs in UPA groundwater was above 1 (HI = 13), primarily due to arsenic, iron, manganese, and thallium (all via the ingestion pathway). The HI associated with potential exposure of an on-post child resident to non-carcinogenic COPCs in UPA groundwater was above 1 (HI = 31), primarily due to arsenic, iron, manganese, thallium, and vanadium (via the ingestion pathway).

It is the lead agency’s current judgment that the preferred RA identified in this PP, or one of the other active measures considered in the PP, is necessary to protect public health or welfare from actual or threatened releases of hazardous substances into the environment.

WHAT IS HUMAN HEALTH RISK AND HOW IS IT CALCULATED?

A Superfund baseline human health risk assessment is an analysis of the potential adverse health effects caused by hazardous substance releases from a site in the absence of any actions to control or mitigate these releases under current- and future-land uses. A four-step process is utilized for assessing site-related human health risks for reasonable maximum exposure scenarios.

Hazard Identification: In this step, the contaminants of concern at the site in various media (i.e., soil, groundwater, surface water, and air) are identified based on such factors as toxicity, frequency of occurrence, fate and transport of the contaminants in the environment, concentrations of the contaminants in specific media, mobility, persistence, and bioaccumulation.

Exposure Assessment: In this step, the different exposure pathways through which people might be exposed to the contaminants identified in the previous step are evaluated. Examples of exposure pathways include incidental ingestion of and dermal contact with contaminated soil. Factors relating to the exposure assessment include, but are not limited to, the concentrations that people might be exposed to and the potential frequency and duration of exposure. Using these factors, a reasonable maximum exposure scenario, which portrays the highest level of human exposure that could reasonably be expected to occur, is calculated.

Toxicity Assessment: In this step, the types of adverse health effects associated with chemical exposures, and the relationship between magnitude of exposure (dose) and severity of adverse effects (response) are determined. Potential health effects are chemical-specific and may include the risk of developing cancer over a lifetime or other non-cancer health effects, such as changes in the normal functions of organs within the body (e.g., changes in the effectiveness of the immune system). Some chemicals are capable of causing both cancer and non-cancer health effects.

Risk Characterization: This step summarizes and combines exposure information and toxicity assessments to provide a quantitative assessment of site risks. Exposures are evaluated based on the potential risk of developing cancer and the potential for non-cancer health hazards. The likelihood of an individual developing cancer is expressed as a probability. For example, a 1E-04 cancer risk means a one-in-ten-thousand excess cancer risk; or one additional cancer may be seen in a population of 10,000 people as a result of exposure to site contaminants under the conditions explained in the Exposure Assessment. The NCP defines the acceptable exposure for an individual as a lifetime excess cancer risk in the range of 1E-04 to 1E-06 (corresponding to a one-in-ten-thousand to a one-in-a-million excess cancer risk). For non-cancer health effects, a hazard index (HI) is calculated. An HI represents the sum of the hazard quotients (HQs) that impact the same target organs. An HQ is calculated by taking the ratio of the individual exposure level for a site-related contaminant as compared to its corresponding reference dose. The reference dose is the dose at which no adverse health effects are anticipated to occur. Therefore, an HQ of one or less indicates that no adverse non-cancer effects are anticipated and, when the HQs for chemicals of concern impacting the same target organ are summed, an HI of one or less also indicates that no adverse non-cancer effects are anticipated to occur.


REMEDIAL ACTION OBJECTIVES

Remedial Action Objectives (RAOs) are developed based on the criteria outlined in Section 300.430(e)(2) of the NCP and Section 121 (d)(2) of CERCLA.

The RAOs for the Site have been developed in such a way that attainment of these goals will result in the protection of human health and the environment.

The RAOs for the Site are:

• To prevent human exposure to site-related COCs in UPA groundwater exceeding MCLs (e.g., arsenic, benzene, and nitrate) and to those site-related COCs in UPA groundwater that pose potential excess risk in the UPA based on the conclusions of the HHRA (including arsenic, iron, and manganese) that would cause unacceptable risk to human health under future land use scenarios.

• To remediate site-related MCL exceedances (e.g., arsenic, benzene, and nitrate) in groundwater beyond the footprint of the CSL landfilled area, and to prevent potential future migration of these constituents beyond the FGGM property boundary in order to restore the UPA at the Site to beneficial use.

Basis for the Establishment of Remedial Action Objectives

A statutory goal of CERCLA is for the Army to take appropriate actions to investigate and, where necessary, address releases of hazardous substances or pollutants that create an imminent and substantial endangerment to the public health or welfare and/or to the environment. The Army is required to select remedies that attain a degree of cleanup that assures protection of human health and the environment. It is the Army’s current judgment that the preferred RA identified in this PP will provide protection to human health and the environment from actual or threatened releases of hazardous substances into the environment.

As presented in the RI Report (EM Federal, 2007), the HHRA determined that there are no risks to human health associated with soil, sediment, and surface water media at FGGM-17. Therefore, this PP focuses solely on risks associated with groundwater contamination in the UPA; and soil, sediment, and surface water are not discussed further. Although extensive sampling of soil, surface water, and sediment performed to date does not indicate that the Site is causing adverse ecological impacts, an ecological risk assessment has not been completed for the CSL. The ecological risk assessment for the entire CSL Site, including the areas addressed by this action, will be performed in support of response actions for Cell 3.

Groundwater chemicals including but not limited to arsenic, iron, manganese, benzene, and nitrate indicate the need for remediation to address MCL exceedances in

UPA groundwater associated with Cells 1 and 2 along the FGGM southeast installation boundary. The groundwater at FGGM-17 will continue to be monitored under the Detection and Assessment Monitoring Program (Arcadis, 2013a) already in place at FGGM-17. The preferred RA will achieve groundwater chemical-specific ARARs which are MCLs. Once groundwater ARARs are achieved, in accordance with the NCP (40 CFR 300.430(e)(2)(i)(D)), a risk assessment will be performed for any residual site-related chemicals to confirm that exposure to UPA groundwater would result in a cumulative excess carcinogenic risk less than or equal to 1E-4, and a noncarcinogenic HI less than or equal to 1 (per target organ). However, attainment of concentrations below background will not be required.

A detailed discussion of ARAR evaluation and analysis is provided in the FFS/ACM (Arcadis, 2014a).

SUMMARY OF REMEDIAL ALTERNATIVES

RAs to address groundwater contamination at the Site were developed and evaluated in the FFS/ACM (Arcadis, 2014a) based upon the results of a preliminary technology evaluation and screening. In addition to No Action, five remedial technologies were also identified and evaluated. These included: Monitored Natural Attenuation (MNA), In-situ Chemical Oxidation (ISCO), Air Sparging, Permeable Reactive Barrier (PRB), and Ex-Situ treatment (Conventional Coagulation/Filtration). ISCO and Ex-situ Treatment (Conventional Coagulation/Filtration) were not retained and included in development of the RAs presented in the following sections because of their inability to satisfy CERCLA threshold criteria. The remedial technology screening process is detailed in the FFS/ACM (Arcadis, 2014a). Detected levels of COCs in groundwater at the Site are sporadic and do not form a cohesive plume. Although there is no discernible plume, there are concentrations of COCs in on- and off-post groundwater that exceed the applicable MCLs at the installation boundary. Screening of remedial technologies detailed below was done in accordance with the requirements of CERCLA, and 40 CFR 258.56, which MDE also uses as a guide for implementation of corrective action measures at sanitary landfills. The RAs are described below with their respective estimated Capital Costs, estimated cost for Operation and Maintenance (O&M) activities, and an estimate of the Present Worth Costs for the RA.

Because none of the remedial alternatives presented in the subsequent sections of this PP will achieve unlimited use and unrestricted exposure scenarios following remedy implementation, annual land use certifications/inspections and the CERCLA five-year review process would be used to document that the remedy remains protective for on-post and off-post areas. For on-post LUCs, the Remedial Design would specify requirements to notify the USEPA should a change in land use occur, or be planned. The Army owns and controls the property and there are no plans to close FGGM in the future. In off-post areas, the Army does not have


jurisdiction to enforce LUCs, but the five-year reviews would document whether controls are still in place. If there are changes to the County’s well permitting program (detailed in Remedial Alternative GW-2 description) that could jeopardize the effectiveness of the off-post groundwater use restrictions implemented by the County, the Army will notify the County of the continued need to maintain the permitting restrictions to protect human health, and notify EPA of the status.

Remedial Alternative GW-1: No Action

Estimated Capital Cost: $0 Estimated O&M Cost Over 30 Years: $0 Estimated Present Worth Cost: $0

Under RA GW-1, no remedial action of any kind would be implemented. This alternative would not adequately control the risks posed by exposure to groundwater; nor would it restore groundwater to its beneficial use at the Site. However, according to the NCP, the no action alternative must be evaluated to establish a baseline for comparison of the remaining alternatives, even though this alternative would not be a viable option itself at this Site. See 40 CFR 300.430(e)(6).

Remedial Alternative GW-2: MNA and LUCs

Estimated Capital Cost: $9,900 Estimated O&M Cost Over 30 Years: $28,600 Estimated Present Worth Cost: $38,500

On-post Land Use Controls and Off-post Groundwater Use Restrictions

Alternative GW-2 would control potential risk to human health by controlling pathways of exposure to COCs in groundwater. As shown in the December 2013 Semi-Annual Groundwater Monitoring Report, natural attenuation processes are controlling migration and steadily reducing COC concentrations of benzene in groundwater (Arcadis, 2013b); however; there are no currently identified declining trends for arsenic in groundwater. In order to determine the potential for MNA as a viable option for arsenic, additional sampling of MNA parameters would be necessary. LTM currently administered under the MDE Solid Waste Program post-closure monitoring program would be incorporated into Alternative GW-2 and would be used to track COC concentrations as part of the CERCLA remedy. Future monitoring of groundwater at the CSL will continue to be implemented in compliance with the MDE Solid Waste Program requirements. In order to supplement LTM activities, an additional off-post permanent monitoring well would be installed as part of the final remedy for the Site and the location would be detailed in the Remedial Design. Additional supporting MNA parameters such as alkalinity, carbon dioxide, methane, nitrate, nitrite, and sulfate would also be analyzed from samples collected at select existing site wells. As previously mentioned, in order to determine the potential for MNA as a viable option for arsenic, additional sampling of MNA parameters would be necessary.

LUCs would prohibit shallow groundwater use on-post at the Site until COCs are at levels that would allow for unlimited use and unrestricted exposure. Existing LUCs already in place at FGGM will be maintained and enhanced. Examples of LUCs planned for implementation at the CSL include prohibition of drilling potable wells and an Army administered permitting process for intrusive work.

The four general categories of LUCs evaluated or already in use at FGGM and applicable to the CSL which provide layers of protection, are as follow: governmental controls, proprietary controls, permitting, and informational devices, which assist with the management and implementation of on-post LUCs. Most of these measures are already in place as elements of required institutional procedures at FGGM. These elements include requirements to obtain dig permits from the Directorate of Public Works for any intrusive activity at FGGM; Master Plan Regulations; FGGM Geographic Information System (GIS) Database; FGGM Access Restrictions; and Army Military Construction Program. These controls have been developed with consideration of all reasonably anticipated land uses at the FGGM; these include recreation and training, as is anticipated for the CSL. These LUCs would be formalized into CERCLA required procedures for the Site.

Alternative GW-2 also includes LUCs in the form of off-post groundwater use restrictions that would be implemented by the County to address site-related MCL exceedances in the UPA in the off-post CSL Study Area. The extent of the off-post CSL Study Area will be confirmed during the Remedial Design phase with the installation and sampling of one additional monitoring well to supplement prior off-post investigations in this area. It is anticipated the off-post groundwater use restrictions will be applicable in the vicinity of Old Waugh Chapel Road east of the CSL and bound by Piney Orchard Pkwy to the east. The type of controls would differ from the LUCs implemented on-post because the off-post area is not under FGGM jurisdiction. The County already has a restriction in place (Special Condition B) to prohibit residential potable well installation within the UPA off-post in the town of Odenton, Maryland. This prohibition is the result of documented radium 224, 226, and 228 contamination in the shallow UPA in this area. The Army would communicate with the County to document that Special Condition B remains in place as part of the County’s well permitting program. The Army would provide written reports to the County with sampling results of the LTM program. The monitoring reports would include updated GIS data layers with updated plume maps for contaminants detected during the LTM program, including an updated list of site-related COCs that exceed MCLs to ensure the County’s groundwater use restriction can be implemented to address all site-related MCL exceedances Additional outreach programs would notify potable/residential well drillers and community members of the potential hazards associated with UPA groundwater in the off-post CSL Area.


Remedial Alternative GW-3: Air Sparging, LUCs, and LTM of Groundwater

Estimated Capital Cost: $436,300 Estimated O&M Cost Over 30 Years: $1,242,300 Estimated Present Worth Cost: $1,678,600 Alternative GW-3 would involve the implementation of Air Sparging, on-post LUCs and off-post groundwater use restrictions as described in Alternative GW-2, and LTM of groundwater. Based on a conceptual design using existing data, 28 air sparge wells would be installed adjacent to the CSL between MW-12S and MW-14 as shown on Figure 4. Assuming that each air sparge well would have a 20-foot radius of influence, a linear length of approximately 1,000 ft would be treated and, thus, essentially form a barrier to contaminant migration along the landfill boundary. It is assumed the air sparge wells would be installed to a depth of 40 ft bgs and screened from 38 to 40 ft bgs, as shown on Figure 5. Based on a typical air sparge design, the system components would include an air compressor, system manifold including actuated valves and a control system housed in an appropriate enclosure. The actuated valves would be installed to allow for pulsed operations for optimized delivery of air to the network of air sparge wells. This would enhance the distribution and increase the residence time for the air to react with the COCs. Alternative GW-3 will volatilize benzene and precipitate inorganic COCs (such as arsenic, iron, and manganese) from the groundwater as the injected air comes in contact with the aquifer across the air sparging barrier. The pulsed operation for a well network of this size is typically designed to have three cycles, enabling eight to nine of the 28 sparge points to be continually operating.

Based on the potential for additional source material contribution from the landfill over the long-term, the air sparge system is assumed to operate for 30 years under this alternative, though the actual duration would be dictated by the results of the post-closure LTM program. The air sparge technology proposed under Alternative GW-3 is designed as a treatment barrier to reduce concentrations of arsenic and benzene to less than their respective MCLs at the FGGM installation boundary. To confirm the effectiveness of the air sparge system, concentration data at performance monitoring wells within or just down-gradient of the air sparge system would be used. Consideration of additional remedies beyond air sparging would be triggered after installation, start-up, and operation of the air sparge system if:

• Arsenic and benzene concentrations remain above MCLs after five years of operation of the air sparge system, and concentrations are not trending toward achievement of MCLs; or

If this triggering condition occurs, alternative approaches presented in the remedial alternative screening analysis completed in the FFS/ACM (Arcadis, 2014a), including the technologies of in-situ chemical oxidation, permeable reactive barriers, and pump and treat would be

considered. It should be noted that a ROD amendment may be required to select an alternative cleanup option at a later point in time. The ROD amendment process would include a detailed description of the proposed alternative and evaluation of the alternative against the nine CERCLA criteria and include the public comment procedures. If an alternative cleanup approach is deemed necessary, an evaluation of the data collected during air sparge operation would be used to select the most appropriate and effective alternative approach. Pilot testing, design, installation, start-up, and a few years of remedial operation would provide data for evaluation of the effectiveness of the remedy. An earlier determination of the need for additional remedies could be made, for instance if pilot testing indicated that air sparging was not effective under site specific conditions. Pilot testing activities would include installation of a limited number of air sparging/performance monitoring wells to confirm the effectiveness of the technology prior to full-scale implementation. Results from pilot testing activities would be made available to all stakeholders for concurrence on the effectiveness before moving to full-scale implementation.

Nitrate in groundwater above the MCL beyond the footprint of the landfill is limited in extent, i.e. limited to monitoring well MW-13S, east of Cell 2, and is not co-located with the benzene and arsenic that would be addressed with air sparging. LTM associated with Alternative GW-3 would include analysis of nitrate at MW-13S to monitor long-term trends. The proposed on-post groundwater use restriction included in Alternative GW-3 would be effective in eliminating human contact with groundwater. Additional investigation and remediation for nitrate, for example carbon injections for in-situ remediation via denitrification, would be triggered if there was an increasing concentration of nitrate, as indicated by statistical analysis, at MW-13S.

Performance monitoring of the air sparging system would be carried out on a periodic basis. During the first year of system operation, performance monitoring would be conducted quarterly. The performance monitoring program would be robust and modified as needed to ensure the effectiveness of the remedy and achievement of RAOs. Approximately six new performance monitoring wells would be installed on the downgradient side of the sparge well line and four performance monitoring wells would be installed on the upgradient side of the sparge well line. The wells would be screened between 20 and 35 ft bgs. Performance monitoring would include analysis of volatile organic compounds and total and dissolved arsenic, iron, manganese, and other key parameters from monitoring wells located southeast of Cell 1 and additional performance monitoring wells displayed on Figure 4.

Similar to Alternative GW-2, Alternative GW-3 would include on-post LUCs- and off-post groundwater use restrictions implemented by the County to prohibit or prevent use of groundwater until COCs in groundwater were at levels that would allow for unlimited use and unrestricted exposure, and LTM of groundwater, both of


which are summarized in the previous section (Alternative GW-2).

Remedial Alternative GW-4: PRB, LUCs, and LTM of Groundwater

Estimated Capital Cost: $3,539,400 Estimated O&M Cost Over 30 Years: $404,300 Estimated Present Worth Cost: $3,943,700 Alternative GW-4 would be employed to passively remove COCs from UPA groundwater at the Site through the installation of a PRB constructed using a reactive medium of Zero Valent Iron (ZVI) and granular activated carbon (GAC) to address arsenic and benzene as groundwater along the southeast CSL landfill boundary flows through the barrier. Alternative GW-4 would also employ on-post LUCs and off-post groundwater use restrictions administered by the County to restrict groundwater use, and LTM of groundwater. Site arsenic impacts extend across the entire length of the proposed PRB (approximately 1,000 linear ft) whereas benzene impacts occur only in the vicinity of MW-19. Figure 6 displays the conceptual PRB layout. The PRB would be installed hydraulically downgradient from the source area (i.e. Cell 1) to intercept and treat COCs and prevent migration of Site COCs beyond the footprint of the landfill and off-post. Groundwater quality down-gradient of the PRB would be improved through the “clean water” exiting the PRB and flushing the down-gradient areas. The design basis, assumptions, and construction specifications are presented in the following paragraphs.

The proposed PRB would consist of an approximate 1,000 ft linear length of reactive medium installed to a depth of approximately 40 ft bgs with a 5 ft thick cap consisting of native material. Approximately 25 percent (%) of the wall length would be designed for both arsenic and benzene removal from groundwater and would be installed in the vicinity of benzene impacts (i.e. MW-19). It is expected that the reactive medium in this section would be comprised of 40% ZVI, 40% GAC, and 20% gravel. It is expected that the reactive medium in the remaining 75% of the wall would be 40% ZVI and 60% gravel and designed for arsenic removal only. Final details of the design including ratios would be finalized in the Remedial Design. Using conservative literature values for arsenic uptake capacity for ZVI, a residence time of approximately six hours is expected to provide effective removal of arsenic. Based on the linear groundwater velocity of approximately 12 ft per year at the proposed PRB locations, a trench approximately 18 inches wide would be required to achieve effective treatment.

It is assumed that single pass trenching would be used to construct the PRB. However, other methods such as deep soil mixing may be specified in the Remedial Design. The reactive medium would be mixed on the surface and placed inside the trench from 40 ft bgs to 5 ft bgs. The top 5 ft would be comprised of native backfilled material. Based on Site analytical data, influent groundwater

concentrations of 50 µg/L and 10 µg/L for arsenic and benzene, respectively, were used as design parameters. The reactive medium in the PRB is expected to be effective for at least 30 years and media replacement would not be required over the 30-year operational timeframe.

Similar to Alternative GW-3, Alternative GW-4 is designed as a treatment barrier to reduce concentrations of arsenic and benzene to less than their respective MCLs outside the footprint of the landfill, thus preventing the migration of contaminants in excess of MCLs beyond the FGGM installation boundary, and to reduce concentrations of COCs such as iron and manganese in Site groundwater to achieve RAOs. Nitrate in groundwater above the MCL beyond the footprint of the landfill is limited in extent, i.e. limited to monitoring well MW-13S, east of Cell 2, and is not co-located with the benzene and arsenic that would be addressed by the PRB. LTM associated with Alternative GW-4 would include analysis of nitrate at MW-13S to monitor long-term trends. The proposed on-post groundwater use restriction included in Alternative GW-4 would be effective in eliminating human contact with groundwater. To demonstrate the effectiveness of the remedy, concentration data at performance monitoring wells within or just down-gradient of the PRB would be used. Conditions that would trigger the need to implement additional remedial measures through a ROD amendment as detailed in the description of Alternative GW-3 also apply to the PRB that would be implemented under Alternative GW-4. Further, if performance monitoring results indicated that the remedy is not on track to achieve RAOs within 5 years following installation of the PRB wall, implementation of an alternative remedy would be considered. Performance monitoring of the PRB would be carried out on a periodic basis and would be detailed in the forthcoming Remedial Design. Similar to Alternative GW-3, six new performance monitoring wells would be installed on the downgradient side of the PRB, and four performance monitoring wells would be installed on the upgradient side. The wells would be screened between 20 and 35 ft bgs.

Performance monitoring parameters would include analysis of Site COCs and geochemical indicators (cations, anions, and general chemistry) to evaluate PRB effectiveness. It is anticipated that groundwater sampled from the performance monitoring wells would be analyzed for arsenic, benzene, iron, sulfate, sulfide, total and dissolved iron and manganese, and pH. This analyte list would be revisited following review of laboratory column testing completed during pre-design investigation activities which would identify the key reactions within the PRB that affect performance and longevity of the remedy.

Similar to Alternatives GW-2 and GW-3, Alternative GW-4 would include on-post LUCs and off-post groundwater use restrictions implemented by the County to prohibit or prevent use of groundwater until COCs in groundwater were at levels that would allow for unlimited use and unrestricted exposure, and LTM of groundwater which are summarized in a previous section (Alternative GW-2).


EVALUATION OF REMEDIAL ALTERNATIVES

The NCP requires the evaluation of remedial alternatives both individually and against one another using nine evaluation criteria, in order to select a remedy (40 CFR 300.430(e)(9)). These criteria are as follow:

Threshold Criteria – Must be met for the RA to be eligible for selection as a remedial option.

1. Overall Protection of Human Health and the Environment – Determines whether an alternative will adequately eliminate, reduce, or control threats to public health and the environment through treatment, engineering controls, or LUCs.

2. Compliance with ARARs – Evaluates whether the RA will meet the requirements set forth in Federal and more stringent State environmental and facility siting statutes and regulations, or whether a waiver is justified. Identification of ARARs is dependent on Site risks and the hazardous substances present at the Site, site characteristics, the Site location, and the actions selected to remediate the Site. Thus, requirements may be chemical-, location-, or action-specific. Please refer to Section 4.2 of the FFS/ACM (Arcadis, 2014a) for a more detailed discussion of ARARs.

Primary Balancing Criteria – Used to weigh major trade-offs among RAs.

3. Long-term Effectiveness and Permanence – Considers the ability of an RA to maintain protection of human health and the environment over time.

4. Reduction of Toxicity, Mobility, or Volume of Contaminants through Treatment – Evaluates the use of treatment in an RA to reduce the harmful effects of principal contaminants, their ability to move in the environment, and the amount of contamination present.

5. Short-term Effectiveness – Considers the length of time needed to implement an RA and the risks the RA poses to workers, residents, and the environment during implementation.

6. Implementability – Considers the technical and administrative feasibility of implementing the RA, including factors such as the relative availability of goods and services.

7. Cost – Includes estimated capital and annual O&M costs, as well as present worth cost. Present worth cost is the total cost of an RA over time in terms of today’s dollar value. Cost estimates are expected to be accurate within a range of –30 to +50 percent.

Modifying Criteria – May be considered to the extent that information is available prior to the start of the

public comment period, but can be fully considered only after public comment is received on this PP.

8. State/Support Agency Acceptance – Considers whether the State agrees with the Army’s analysis and recommendations, as described in the RI, FFS/ACM and PP.

9. Community Acceptance – Considers whether the local community agrees with the Army’s analysis and preferred RA. Comments received on the PP are an important indicator of community acceptance.

Comparative Analysis of Remedial Alternatives

This section summarizes the comparative analysis of RAs for the Site that were presented in the FFS/ACM (Arcadis, 2014a). A chart summarizing this comparative analysis is included as Table 1. Each alternative is ranked; 1 (being the best) and 3 (being the worst) for each of the criteria. The rankings are then averaged for each alternative.

Overall Protection of Human Health and the Environment

Alternative GW-1 would not be protective of human health because it does not include any on-post LUCs or Army verification of off-post groundwater use restrictions implemented by the County to prevent groundwater use, which could present an unacceptable risk to human health. Therefore, since it does not satisfy this threshold criterion, Alternative 1 will not be considered further in this analysis. Alternatives GW-2, GW-3, and GW-4 would either remove contaminants through treatment, or control exposures through the implementation of on-post LUCs and off-post groundwater use restrictions (implemented by the County), to prevent possible future exposure to COCs in impacted groundwater on- and off-post.

Alternatives GW-3 and GW-4 would provide the highest level of overall protection because of the active treatment of Site COCs which would reduce contaminant concentrations in groundwater outside the footprint of the landfill to meet MCLs and RAOs. Alternative GW-2 ranks lower than Alternatives GW-3 and GW-4 on overall protection because it lacks active treatment. Additionally, Alternative GW-2 might not meet the cleanup goals for arsenic. As previously mentioned, in order to determine the potential for MNA as a viable option for arsenic, additional sampling of MNA parameters would be necessary. Alternatives GW-2, GW-3, and GW-4 would implement on-post LUCs and rely on off-post groundwater use restrictions implemented by the County to prevent human contact with COCs in groundwater until COCs are at levels that allow for unlimited use and unrestricted exposure, and establish a program to monitor COC concentrations in UPA groundwater on- and off-post to confirm that COC concentrations are declining.

Compliance with ARARs

Under Alternative GW-2, exposure pathways would be controlled, and MNA would track groundwater conditions and COC concentrations until MCLs were met, in order to


comply with chemical-specific ARARs. However, because arsenic is not currently decreasing under natural conditions and would likely not fall below the MCL within a reasonable timeframe (i.e. 30 years), Alternative GW-2 may not fully achieve ARARs and the second RAO. Alternatives GW-3 and GW-4 would comply with all chemical- and action-specific ARARs for COCs in groundwater and the RAs contemplated. There are no location-specific ARARs associated with this Site.

Long-Term Effectiveness and Permanence

Alternative GW-2 would be effective in the long-term because it would reduce risk to human health by prohibiting groundwater use, thus removing the pathways of exposure to COCs in groundwater. However, Alternative GW-2 would likely take longer than 30 years to achieve MCLs through MNA of groundwater and to satisfy the second RAO. Alternatives GW-3 and GW-4 would be more effective in the long term than Alternative GW-2 because they would both provide effective and permanent solutions to protect human health and the environment by reducing COCs in the UPA groundwater. Alternative GW-3 would permanently reduce COCs in UPA groundwater by volatilizing or precipitating them; and Alternative GW-4 would permanently treat COCs in UPA groundwater as it migrates through the PRB, flushing MCL-compliant water into the down-gradient area in order to achieve RAOs. Alternatives GW-3 and GW-4 both include performance monitoring and LTM components of the remedy which would establish means to monitor the expected decline of COCs in UPA groundwater.

Reduction of Toxicity, Mobility, and Volume through Treatment

Alternative GW-2 would not reduce the toxicity, mobility, and volume of COCs through treatment of impacted groundwater at the Site. Alternatives GW-3 and GW-4 would reduce the toxicity, mobility, and volume of COCs through in-situ treatment; thus, they would both satisfy this criterion.

Short-Term Effectiveness

Alternative GW-2 scores the highest under this criterion since it would not pose any additional risks to the community, workers, or the environment as there are no active remedial measures associated with its implementation. Alternatives GW-3 and GW-4 would be moderately effective in the short term, since they would present only minimal risk to the community and workers during construction of the active remediation for groundwater treatment. Alternative GW-3 and GW-4 could both be implemented in less than 1 year.

Implementability

Alternative GW-2 requires minimal time and coordination of labor, materials, and resources necessary for implementation and completion, and, therefore, Alternative GW-2 scores the highest under this criterion. Alternative GW-3 would be technically and administratively feasible and would require the installation

of wells, remediation equipment and a power supply which would require proper planning and equipment procurement. The implementation of Alternative GW-4, which scores the lowest under this criterion, would present some challenges regarding siting the remedial components due to the minimal available space. However, these challenges could be mitigated through proper planning and procurement of appropriate equipment to implement construction of the PRB.

Cost

Based on the present worth estimates of probable costs for the alternatives, Alternative GW-2 has the lowest projected present worth cost ($38,500). However, it provides no potential risk reduction or active treatment to address RAOs, including MCL exceedances, at the FGGM property boundary. Alternative GW-3 ($1,678,600) would be less costly than Alternative GW-4 ($3,943,700). Both GW-3 and GW-4 include active measures to address groundwater contamination at the CSL, which would achieve RAOs outside the footprint of the landfill, thus preventing further migration of COCs above RAOs beyond the property boundary.

State/Support Agency Acceptance

State approval of the preferred RA presented in this PP is expected. State approval will be further evaluated in the ROD following the public comment period.

Community Acceptance

Community acceptance of the preferred RA will be evaluated at the conclusion of the public comment period. Comments received will be addressed in the Responsiveness Summary prepared for the ROD.


Table 1: Comparative Analysis Chart

Remedial Alternative GW-1 No Action

Remedial Alternative GW-2 Monitored Natural Attenuation and Land Use Controls

Remedial Alternative GW-3 Air Sparging with Land Use Controls and

Long-term Monitoring of Groundwater

Remedial Alternative GW-4 Permeable Reactive Barrier with Land Use

Controls and Long-term Monitoring of Groundwater

Evaluation Criteria

Description Rank Description Rank Description Rank Description Rank

Overall Protection of Human Health and the Environment

The no-action alternative would provide no control of exposure to impacted groundwater at the Site and no reduction in risk to human health. Currently there is no unacceptable risk to human health under current land use scenarios; however, there are risks associated with the future on-site residential land use scenario. On-going groundwater sampling events have detected multiple contaminants above their respective MCLs in samples collected from the UPA. Therefore, Alternative 1 does not meet this criterion for overall protection of human health and the environment.

3

Formalization of on-post LUCs to prohibit groundwater use at the Site would limit uncontrolled exposure to groundwater, thereby controlling potential future unacceptable risks to human health. Further, off-post groundwater use restrictions implemented by the County would eliminate the potential for residents to become exposed to impacted groundwater, thereby controlling potential future unacceptable risks to human health. MNA would eventually achieve MCLs and the second RAO, although this would likely not occur within a reasonable timeframe of 30 years.

2

Alternative GW-3 would protect human health and the environment by eliminating potential exposure to COCs in groundwater through implementation of on-post LUCs and off-post groundwater use restrictions until RAOs are achieved (anticipated 30 years from implementation) through active remediation (i.e. air sparging). Air sparging would reduce the concentrations of COCs below MCLs to achieve the RAO to remediate the groundwater to beneficial use. Groundwater monitoring would confirm the anticipated reduction of COCs.

1

Alternative GW-4 would protect human health and the environment by eliminating potential exposure to COCs in groundwater through implementation of on-post LUCs and off-post groundwater use restrictions until RAOs are achieved (anticipated 30 years from implementation) through active remediation (i.e. PRB installation). Installation of the PRB would reduce the concentrations of COCs below MCLs to achieve the RAO to remediate the groundwater to beneficial use. LTM would confirm the anticipated reduction of COCs.

1

Compliance with ARARs

Chemical-specific ARARs would not be met by the No Action alternative.

3

This alternative would only partially comply with the chemical-specific ARARs; while benzene concentrations are apparently declining in response to natural attenuation processes, it does not appear that arsenic concentrations are diminishing. In order to determine the potential for MNA as a viable option for arsenic, additional sampling of MNA parameters would be necessary.

2

This alternative would comply with chemical-specific ARARs and would be implemented in accordance with action-specific ARARs. There are no location-specific ARARs related to the RAs at this Site.

1

This alternative would comply with chemical-specific ARARs and would be implemented in accordance with action-specific ARARs. There are no location-specific ARARs related to the RAs at this Site.

1

Long-term Effectiveness and Permanence

The no-action alternative would not monitor reduction of contaminant concentrations over time, reduce exposure through the implementation of on-post LUCs or verify the continued application of off-post groundwater use restrictions, or employ any long-term management measures. Potential future risks would remain under this alternative.

3

Implementation of on-post LUCs and off-post groundwater use restrictions would be effective in the long-term to prevent unacceptable risks to human health posed by groundwater use on- and off-post. The Army could ensure the permanence of the on-post LUCs which would be implemented through existing controls that would remain in place for the foreseeable future, as ownership of the Site is not planned to change and will remain with the Army. Further, the MNA component of the remedy establishes means to monitor the anticipated reduction of COCs in groundwater on- and off-post.

2

This alternative would provide effective and permanent protection of human health and the environment. Air sparging would help to permanently reduce COCs through volatilization (benzene) and precipitation (arsenic), thus preventing further migration of COCs at concentrations in excess of RAOs beyond the footprint of the landfill and across the property boundary. The performance monitoring and LTM components of the remedy establish means to monitor the performance of the remedy on- and off-post.

1

This alternative would provide effective and permanent protection of human health and the environment. Installation of a PRB wall would help to permanently reduce concentrations of COCs as groundwater migrates through the barrier. The performance monitoring and LTM components of the remedy establish means to monitor the performance of the remedy on- and off-post.

1


Remedial Alternative GW-1 No Action

Remedial Alternative GW-2 Monitored Natural Attenuation and Land Use Controls

Remedial Alternative GW-3 Air Sparging with Land Use Controls and

Long-term Monitoring of Groundwater

Remedial Alternative GW-4 Permeable Reactive Barrier with Land Use

Controls and Long-term Monitoring of Groundwater

Evaluation Criteria

Description Rank Description Rank Description Rank Description Rank

Reduction of Toxicity, Mobility, and Volume through Treatment

This alternative would not employ treatment that would reduce the toxicity, mobility, or volume of contaminants in groundwater; therefore, it does not satisfy this criterion.

3

This alternative would not employ treatment that would reduce the toxicity, mobility, or volume of contaminants in groundwater; therefore, it does not satisfy this criterion.

3

Air sparging would reduce the toxicity, mobility, and volume of COCs in groundwater through in-situ treatment.

1 Installation of a PRB wall would reduce the toxicity, mobility, and volume of COCs in groundwater through in-situ treatment.

1

Short-term Effectiveness

Since one element of this criterion is “time until protection is achieved,” and the “No Action” alternative would not achieve protection, this alternative does not satisfy this criterion.

3

This alternative does not pose any additional risks to the community, the workers, or the environment as there are no active remedial measures associated with its implementation. This alternative could be implemented immediately.

1

Marginal short-term risks to the community and construction workers would be present during air sparge system installation. However, the potential for exposure to Site COCs during implementation would be reduced through the use of suitable protective clothing and equipment and standard construction practices. This alternative could be implemented in less than 1 year.

2

Marginal short-term risks to the community and construction workers would be present during PRB wall installation. However, the potential for exposure to Site COCs during implementation would be reduced through the use of suitable protective clothing and equipment and standard construction practices. This alternative could be implemented in less than 1 year.

2

Implementability

Since no remedial actions would be taken, there would be no “implementability” issues.

1

There are no implementability concerns posed by this option as this alternative requires minimal time and coordination of labor, materials, and resources for completion and would take advantage of the existing monitoring well network.

1

This alternative is technically and administratively feasible. Air sparge pilot testing would be required as part of the remedial design to confirm operational specifications. Also, a significant amount of infrastructure including new wells, equipment, and power supply would need to be installed.

2

This alternative is technically and administratively feasible. Pre-design investigation would be required to confirm design parameters and to determine site-specific arsenic and benzene uptake estimates. Also, available room at the Site is limited, which presents implementability concerns, but project planning and procurement of appropriate equipment could mitigate implementability challenges.

3

Cost

There would be no capital or O&M costs for the no-action alternative, and hence no present worth cost, because there would be no action taken.

1

Low to moderate cost associated with maintaining the on-post LUCs and off-post groundwater use restrictions and MNA (Total Present Worth Cost - $38,500).

1

Moderate to high cost associated with Air sparging, on-post LUCs and off-post groundwater use restrictions, and LTM (Total Present Worth Cost - $1,678,600)

2

High cost associated with PRB, on-post LUCs off-post groundwater use restrictions, and LTM. (Total Present Worth Cost - $3,943,700)

3

State/Support Agency Acceptance

To be determined (TBD) TBD TBD TBD

Community Acceptance

TBD TBD TBD TBD

Averaged ranking

2.4 1.7 1.4 1.7

Overall rank 4 2 1 2

Notes: 1 – Highest ranking, most favorable 2 – Moderate ranking 3 – Lowest ranking, least favorable

Final 16 Proposed Plan May 2017 The Closed Sanitary Landfill (FGGM-17)

Fort George G. Meade, Maryland

SUMMARY OF THE PREFERRED REMEDIAL ALTERNATIVE FOR FGGM-17

The results of the HHRA (EM Federal, 2007) and supplemental risk evaluation (Arcadis, 2014a) indicate that surface/sub-surface soil, sediment, and surface water media at the Site do not present unacceptable risk to human receptors on- and off-post. However, exposure to groundwater under future land use scenarios at the Site would present unacceptable risks. Further, MCL exceedances in Upper Patapsco groundwater associated with landfill Cells 1 and 2 along the southeast FGGM installation boundary are driving necessary action at the FGGM-17. Therefore, the preferred RA is recommended because it would provide the best balance among the evaluation criteria for treatment of groundwater contamination in the UPA at the Site.

The preferred RA is:

• Remedial Alternative GW-3: Air Sparging, LUCs,and LTM of Groundwater.

Based on the results of the comparative analysis and detailed evaluation presented in the FFS/ACM (Arcadis, 2014a), the Army recommends that Remedial Alternative GW-3 be implemented as the preferred alternative for remediation of contaminants in UPA groundwater at the Site. Alternative GW-3 is the most appropriate remedy for UPA groundwater contamination at the Site because it would protect human health and the environment by eliminating potential exposure to COCs in groundwater through the implementation of on-post LUCs by the Army and off-post groundwater use restrictions by the County until RAOs are achieved (anticipated 30 years from implementation) through active remediation (i.e. air sparging), and it would provide the best balance of tradeoffs relative to the five primary balancing criteria described in the Evaluation of Remedial Alternatives section above. Alternative 4 is similar in effectiveness; reduction of toxicity, mobility, and volume through treatment; and implementability. However, the cost of Remedial Alternative GW-3 ($1,678,600) is less than half of the cost for Remedial Alternative GW-4 ($3,943,700); hence, Alternative GW-3 would be more cost effective.

Under Alternative GW-3, maintenance of on-post LUCs to prohibit groundwater use would control exposure to UPA groundwater on the installation, and off-post groundwater use restrictions implemented by the County would control human contact with COCs in groundwater off the installation. Unacceptable risks under future land use scenarios would be addressed through LUCs and air sparging to eliminate human contact with UPA groundwater and reduce the concentrations of COCs below MCLs or the total-risk-based RAO, thus returning the aquifer to its beneficial use.

Semi-annual groundwater monitoring would be a necessary component of the CERCLA remedy at the Site and would also comply with the MDE Solid Waste Program requirements for groundwater monitoring, and

COMAR 26.04.07.22. The actions implemented under the preferred RA would also comply with the substantive requirements of the following State of Maryland regulations, which are also action-specific ARARs: Erosion and Sediment Control (COMAR 26.17.01.07 and 26.17.01.11); Control of Noise Pollution (COMAR 26.02.03.01 through 26.02.03.03); and Well Construction, Maintenance, and Abandonment (COMAR 26.04.04.02, 26.04.04.07, 26.04.04.10, and 26.04.04.11).

The preferred RA can be changed in light of new information or in response to public comments as described below.

Based on information currently available, the Army believes the preferred RA meets the threshold criteria and provides the best balance of tradeoffs among the other RAs with respect to the balancing criteria. The Army expects the preferred RA to satisfy the following statutory requirements of CERCLA 121(b): 1) to be protective of human health and the environment; 2) to comply with ARARs; 3) to be cost-effective; 4) to utilize permanent solutions and alternative treatment technologies to the maximum extent practicable; and, 5) to satisfy the preference for treatment as a principal element.

COMMUNITY PARTICIPATION

Public participation is an important component of remedy selection. The Army, USEPA, and MDE are soliciting input from the community on the preferred RA. The comment period extends from May 18, 2017 to June 17, 2017 (30 days). This period includes a public meeting at which the Army will present the PP as agreed to by the USEPA and MDE. The Army will accept both oral and written comments at this meeting and written comments following the meeting through June 17, 2017.

The Restoration Advisory Board (RAB) is a critical component of the FGGM Installation Restoration Program to keep the public informed about the environmental cleanup activities and to involve the public in decision-making. The RAB gives community members, particularly those who may be affected by the cleanup activities, and government representatives a chance to exchange information and participate in meaningful dialogue. The Site has previously been discussed with the RAB in 2009 as part of the commencement of the overall Performance Based Contract activities. The RAB has been updated regarding the Site periodically since that time, most recently during the September 18, 2014 RAB meeting.

Public Comment Period

The Army is providing a 30-day comment period from May 18, 2017 to June 17, 2017 to provide an opportunity for public involvement in the decision-making process for the proposed action. The public is encouraged to review and comment on this PP, as the final remedy selected for this Site can change as a result of public comments received. During the public comment period, the public is encouraged to review the following reports and other documents pertinent to FGGM-17 and the Superfund process: Closed Sanitary Landfill Groundwater Remedial


Investigation (EM Federal, 2007), Plume Delineation and Analytical Data Summary Memorandum (Arcadis, 2014b), Semi-Annual Monitoring Report for the Closed Sanitary Landfill (Arcadis, 2013b), and the FFS/ACM (Arcadis, 2014a). This information is available at the Anne Arundel County Library, West County Area Branch located at 1325 Annapolis Road in Odenton, MD, and the Fort George G. Meade Environmental Division Office, located in Building 2460 on 85th Medical Battalion Ave. at Fort George G. Meade. To obtain further information, the following representatives may be contacted:

Ms. Mary Doyle U.S. Army Garrison Fort George G. Meade

Public Affairs Office 4409 Llewellyn Avenue Fort Meade, MD 20755

(301) 677-1361 [email protected]

Mr. Robert Stroud Remedial Project Manager - USEPA Region III

701 Mapes Road Fort Meade, MD 20755

(410) 305-2748 [email protected]

Ms. Elisabeth Green, Ph.D. Maryland Department of the Environment

Federal Facilities Division 1800 Washington Blvd. Suite 625

Baltimore, MD 21230-1719 (410) 537-3346

[email protected]

Army’s Review of Public Comments

The Army will review the public’s comments as part of the process to reach a final decision on the remedial action to be taken. The Army’s final choice of action will be issued in a ROD. A Responsiveness Summary, documenting and responding to significant written and oral comments received from the public during the public comment period will be issued with the ROD. Once community response and input are received and the Army and USEPA sign the ROD, it will become part of the Administrative Record.

mailto:[email protected]


ACRONYMS AND ABBREVIATIONS

% ....................................... percent µg/L .................................. micrograms per liter ACM .................................. Assessment of Corrective Measures ARARs .............................. Applicable or Relevant and Appropriate Requirements Arcadis .............................. Arcadis US, Inc. Army.................................. U.S. Department of the Army ASP ................................... Ammunition Supply Point bgs .................................... below ground surface BRAC ................................ Base Realignment and Closure CERCLA ........................... Comprehensive Environmental Response, Compensation, and Liability Act of 1980, as amended CFR................................... Code of Federal Regulations COC ................................. Constituent of Concern COPC................................ Constituent of Potential Concern COMAR ............................. Code of Maryland Regulations County............................... Anne Arundel County Health Department CSL ................................... Closed Sanitary Landfill DPT ................................... Direct-Push Technology EC ..................................... Engineering Control EPC................................... Exposure Point Concentration FFA ................................... Federal Facility Agreement FFS ................................... Focused Feasibility Study FGGM ............................... Fort George G. Meade FGGM-17 .......................... Closed Sanitary Landfill ft ........................................ feet or foot GAC .................................. Granular Activated Carbon GIS .................................... Geographic Information System HHRA ................................ Human Health Risk Assessment HI ...................................... Hazard Index or Indices HQ .................................... Hazard Quotient ISCO ................................. In-situ Chemical Oxidation LPA ................................... Lower Patapsco Aquifer LTM ................................... Long-Term Monitoring LUC ................................... Land Use Control MCL .................................. Maximum Contaminant Level MDE .................................. Maryland Department of the Environment mg/L ................................. milligrams per liter MNA .................................. Monitored Natural Attenuation NCP .................................. National Oil and Hazardous Substances Pollution Contingency Plan NPL ................................... National Priorities List O&M .................................. Operation and Maintenance PP ..................................... Proposed Plan PRB................................... Permeable Reactive Barrier RA ..................................... Remedial Alternative RAB................................... Restoration Advisory Board RAO .................................. Remedial Action Objective RCRA ................................ Resource Conservation and Recovery Act RI ...................................... Remedial Investigation ROD .................................. Record of Decision TBD ................................... To Be Determined U.S. ................................... United States UPA................................... Upper Patapsco Aquifer USEPA .............................. U.S. Environmental Protection Agency WWI .................................. World War I ZVI .................................... Zero Valent Iron


GLOSSARY OF TERMS

Administrative Record: This is the collection of documents (including plans, correspondence and reports) generated during site investigation and remedial activities that were referred to or relied upon to select the preferred Response Action. Information in the Administrative Record is available for public review. 40 CFR 300.800

Applicable or Relevant and Appropriate Requirements (ARARs): The federal and State statutory and regulatory environmental and facility siting requirements that a selected remedy must attain. These requirements may vary among sites and RAs. 40 CFR 300.5

Capital Costs: This includes costs associated with construction, treatment equipment, site preparation, services, transportation, disposal, health and safety, installation and start-up, administration, legal support, engineering, and design associated with Response Actions.

Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA): This federal law was passed in 1980, and has been subsequently amended, and is commonly referred to as the Superfund Program. It provides for emergency response, liability, cleanup, and compensation in connection with the cleanup of inactive hazardous waste disposal sites that endanger public health and safety or the environment.

Focused Feasibility Study (FFS): This CERCLA document reviews the chemicals of concern at a site, and evaluates multiple remedial technologies for use at the site. Finally, it identifies the most feasible Remedial Alternative.

Human Health Risk Assessment (HHRA): This assessment describes the formal step-by-step scientific process for quantifying health risks to human receptors (residents, workers, trespassers), thereby estimating the nature and probability of adverse health effects in humans who may be exposed to chemicals in contaminated environmental media under current or future scenarios. A risk assessment uses standardized tools, formats, and scientifically accepted assumptions.

National Oil and Hazardous Substances Pollution Contingency Plan (NCP): These CERCLA regulations provide the federal government with the authority to respond to the problems of abandoned or uncontrolled hazardous substance disposal sites as well as to certain incidents involving hazardous wastes (e.g., spills).

National Priorities List (NPL): The list of contaminated sites that require cleanup under CERCLA and where CERCLA funds may be expended.

Operation and Maintenance (O&M) Costs: Annual post-construction costs necessary to ensure the continued effectiveness of a Response Action.

Present Worth Costs: Used to evaluate expenditures that occur over different time periods by discounting all future costs to a common base year. This allows the cost of the Response Actions to be compared on the basis of a single figure representing the amount of money that would be sufficient to cover capital and O&M costs associated with each Response Action over its planned life.

Record of Decision (ROD): This is the document in which the remedial action for a CERCLA site is selected, and it is signed by the Army and the USEPA in consultation with the MDE. It describes the cleanup action or remedy selected for a site, the basis for selecting that remedy, public comments, responses to comments, and the estimated cost of the remedy.

Remedial Investigation (RI): An investigation under CERCLA that involves sampling environmental media such as air, soil, and water to determine the nature and extent of contamination at a site and the human health and environmental risks that result from the contamination present at a site.

Responsiveness Summary: A part of the ROD in which the Army documents and responds to written and oral comments received during the public comment period regarding the alternatives presented in the PP.

Restoration Advisory Board (RAB): The board provides a forum for exchange of information and partnership among citizens, the military installation, USEPA, and MDE. The RAB offers an opportunity for community members to provide input into the cleanup process.


REFERENCES

Arcadis US, Inc. (Arcadis). 2009. Comments and Responses on the Final Remedial Investigation Report (August 2007)

for U.S. Army Garrison, Ft. George G. Meade, Fort Meade, MD FGGM-17, Closed Sanitary Landfill Fort Meade,

Anne Arundel County, MD; September 23, 2009.

Arcadis. 2013a. 2013 Monitoring Plan for FGGM-17, Closed Sanitary Landfill, Fort George G. Meade, Maryland.

February 2013.

Arcadis. 2013b. Semi-Annual Monitoring Report for the Closed Sanitary Landfill, Fort George G. Meade, Maryland.

December 2013.Arcadis. 2014a. Focused Feasibility Study/Assessment of Corrective Measures. FGGM-17,

Closed Sanitary Landfill, Fort George G. Meade, Maryland. Draft Final. October 2014.

Arcadis. 2014b. Plume Delineation and Analytical Data Summary Memorandum. Closed Sanitary Landfill, Fort George

G. Meade, Maryland. January 2014.

ATKINS. 2011. Real Property Master Plan Digest for Fort George G. Meade, Maryland. October 2011.

EM Federal Engineering. 2007. Closed Sanitary Landfill Final Groundwater Remedial Investigation, Fort George G.

Meade, Maryland. Final. 2007.

Stell Environmental. 2014. Amended Site Management Plan, Fort George G. Meade, Maryland, Final. Prepared for

U.S. Army Corps of Engineers Baltimore District. August 2014.

United States Environmental Protection Agency (USEPA). 1991. Risk Assessment Guidance for Superfund: Volume

I—Human Health Evaluation Manual (Part B, Development of Risk-based Preliminary Remediation Goals).

EPA/540/R-92/003. December.

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FORT GEORGE G. MEADE

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FIGURE EXTENT

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CLOSED SANITARY LANDFILL FORT GEORGE G. MEADE, MARYLAND

THIS DRAWING IS THE PROPERTY OF THE ARCADIS ENTITY IDENTIFIED IN THE TITLE BLOCK AND MAYNOT BE REPRODUCED OR ALTERED IN WHOLE OR IN PART WITHOUT THE EXPRESS WRITTEN

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SERVICE LAYER CREDITS: SOURCE: ESRI, DIGITALGLOBE, GEOEYE, EARTHSTAR GEOGRAPHICS,CNES/AIRBUS DS, USDA, USGS, AEROGRID, IGN, AND THE GIS USER COMMUNITY

FORT GEORGE G. MEADE

CSL

FIGURE EXTENT

0 1 2

Miles

GRAPHIC SCALE

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