^eD srx * o \ I® J UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION 6 FINAL DECISION AND RESPONSE TO COMMENTS US ARMY CAMP STANLEY STORAGE ACTIVITY BOERNE, TEXAS EPA RCRA ID No. TX2210020739 ------- I. FINAL DECISION The United States Environmental Protection Agency (EPA) is issuing this Final Decision and Response to Comments (Final Decision) selecting the Final Remedy for the US Army Camp Stanley Storage Activity (CSSA) facility located in Boerne, Texas (hereinafter referenced to as the Facility). This Final Decision is issued pursuant to the Solid Waste Disposal Act, as amended by the Resource Conservation and Recovery Act (RCRA) of 1976, and the Hazardous and Solid Waste Amendments (HSWA) of 1984, 42 U.S.C. Sections 901, et seq. II. PUBLIC COMMENT PERIOD On March 24, 2015, EPA issued the Statement of Basis (SB) utilizing all of the information gathered during the environmental investigations at the Facility and proposed the Preferred Alternatives for corrective action at the Facility. The SB is hereby incorporated into this Final Decision by reference and made a part hereof as Attachment A. Consistent with public participation provisions under RCRA, EPA requested comments from the public on the proposed remedy as described in the SB. The commencement of a thirty (30) day public comment period was announced on the EPA Region 6 website and with a mailed announcement to all community members in the vicinity of the Facility. A Formal Public Meeting to discuss the SB was announced in the San Antonio Express-News on April 12, 2015, and April 19, 2015, and in the Boerne Star on April 10, 2015, and April 17, 2015. The public comment period began on April 8, 2015, and ended on May 8, 2015. The Formal Public Meeting was held on April 23, 2015. III. RESPONSE TO COMMENTS The EPA did not receive any comments on the SB. Consequently, our final determination is unchanged from the Preferred Alternatives presented in the SB. IV. AUTHORITY EPA is issuing this Final Decision under the authority of the Solid Waste Disposal Act, as amended by RCRA, and the Hazardous and Solid Waste Amendments (HSWA) of 1984, 42 U.S.C. Sections 6901 to 6992. The required corrective actions in the SB will be implemented in accordance with, and pursuant to, the final RCRA §3008(h), 42 U.S.C §6928(h) Administrative Order on Consent for CSSA, dated May 5, 1999. V. DECLARATION Based on the Administrative Record compiled for the Corrective Action at the US Army Camp Stanley Storage Activity facility, the EPA has determined that the Final Remedies selected in this Final Decision and Response to Comments are protective of human health and the environment. Da iv Deputy Regional Administrator U.S. EPA Ret .on 6 ------- Attachment A EPA Statement of Basis for CSSA Link to the CSS A SB http://www.epa. gov/earthl r6/6pd/rcra c/ca/camp-stanlev-sob.pdf ------- Statement of Basis, Camp Stanley Storage Activity STATEMENT OF BASIS RCRA CORRECTIVE ACTION CAMP STANLEY STORAGE ACTIVITY BOERNE, TEXAS THE PURPOSE OF THE STATEMENT OF BASIS IS TO: • Identify the proposed rem- edy for addressing contam- ination at the site and ex- plain the reasons for the preference; • Describe remedial options considered in the Correc- tive Measures Study; • Solicit public review and comment on the alterna- tives and information con- tained in the Administrative Record; • Provide information on how the public can be involved in the remedy selection process; and • Provide history and back- ground about the facility and environmental sites Figure 1: Camp Stanley Storage Activity Location Map USEPA ANNOUNCES STATEMENT OF BASIS This Statement of Basis issued by the U.S. Environmental Protection Agency (USEPA) describes the pro- posed remedies to address groundwater contamination at US Army Camp Stanley Storage Activity (CSSA) in Boerne, Texas (Figure 1) as required by the Resource Conservation and Recovery Act (RCRA) 3008(h) Administrative Order on Consent (Order) issued on May 5, 1999. In addition, the Statement of Basis includes summaries of other alternative remedies evaluated for the facility and the rationale for USEPA's preference. USEPA, the lead agency for remedial activities at the site, in consultation with the Texas Commission on Environmental Quality (TCEQ), will select a final remedy for CSSA only after the public comment period has ended, and the information submitted during this time is reviewed and consid- ered in the decision-making process. CSSA Statement of Basis Page | 1 March 24, 2015 ------- Statement of Basis, Camp Stanley Storage Activity This Statement of Basis is issued by USEPA as part of its public participation responsibilities un- der RCRA. Addressing stakeholders concerns is critical to the success of the final remedy. Words in bold text are defined in the glossary at the end of this Statement of Basis. The Statement of Ba- sis summarizes information that can be found in greater detail in the Administrative Record (the CSSA Environmental Encyclopedia). The con- ceptual site model and summation of the current status of Solid Waste Management Units (SWMUs) and environmental Areas of Concern (AOCs) are provided in RCRA Facility Investi- gation (RFI) (Parsons 2014b) and Corrective Measures Study (CMS) (Parsons 2014c) re- ports. FACILITY BACKGROUND SITE DESCRIPTION AND HISTORY CSSA is located in northwestern Bexar County, about 19 miles northwest of downtown San Anto- nio. The installation consists of 4,004 acres im- mediately east of Ralph Fair Road, and approxi- mately 0.5 mile east of Interstate Highway (IH) 10. Camp Bullis borders CSSA completely on the east, and partially on the north and south. The present mission of CSSA is the receipt, storage, issue, and maintenance of ordnance as well as quality assurance testing and maintenance of mil- itary weapons and ammunition. Because of its mission, CSSA has been designated a restricted access facility. No changes to the CSSA mission and/or military activities are expected in the fu- ture. The land where CSSA is located was used for ranching and agriculture until the early 1900s. During 1906 and 1907, six tracts of land were pur- chased by the U.S. Government and designated the Leon Springs Military Reservation. These tracts were used as military campgrounds and cavalry shelters. In October 1917, the installation was redesig- nated Camp Stanley. Extensive construction started during World War I to provide temporary cantonments and support facilities. In 1931, the installation was selected as an ammunition depot. Construction of standard earth-covered maga- zines and igloo magazines began in 1938. Land was also used to test, fire, and overhaul ammuni- tion components. As a result of these historic ac- tivities, CSSA had a number of waste sites, in- cluding SWMUs, AOCs, and Range Manage- ment Units (RMUs) (Figure 2). HISTORY OF CONTAMINATION AT CSSA In 1991, routine water well testing by the Texas Department of Health (TDH) detected the pres- ence of dissolved cleaning solvent tetrachloroe- thene (PCE) and related degradation products above maximum contaminant levels (MCLs) in a CSSA water supply well (Well 16[CS-16]). Con- sequently, the well was taken out of service. Sub- sequent sampling showed volatile organic com- pound (VOC) contaminant concentrations greater than MCLs in several other wells. The po- tential sources of the contamination were identi- fied as the former oxidation pond (SWMU 0-1) and Burn Area 3 (SWMU B-3); this area is re- ferred to as Plume 1 (Figure 3). Later, AOC-65, an area of past solvent use, was identified as an- other source of groundwater contamination, re- ferred to as Plume 2 (Figure 3). In 1999, VOCs were detected in privately owned wells off-post near Plume 2. A synopsis of historical use and remedial activities at each of these sites is pro- vided in the RFI Report (Parsons 2014b), and a brief description of the contaminant plumes is provided in the Facility Investigation portion of this document. The main CSSA Contaminants of Concern (COCs) are tetrachloroethene (PCE), trichloroethene (TCE), c/'s-1,2-dichloroethene, frans-1,2-dichloroethene, and vinyl chloride (VC). REGULATORY HISTORY The 1999 Order requires CSSA to identify, investigate, and prevent the further spread of releases of hazardous wastes and/or hazardous constituents to the environment at and/or from CSSA, and to ensure that corrective action activities are implemented to protect human health and the environment. CSSA engaged in a series of environmental investigations during the ensuing 15 years to aid in the horizontal and vertical delineation of solvent contamination source areas within the aquifer. Since the Order was issued in 1999, CSSA has been closing sites under State of CSSA Statement of Basis Pago | 2 March 24, 2015 ------- Statement of Basis, Camp Stanley Storage Activity _.JAOC-73l I Investigation Complete ' * Closure Approved | | Cleanup in Progress ~ Active Range Complex Range Fan with Buffers lBLDG-401 \ CAMP BULLIS 0.5 Miles Figure 2: Locations and Status of Remedial Sites at CSSA CSSA Statement of Basis Page | 3 March 24, 2015 ------- Statement of Basis, Camp Stanley Storage Activity PCE Concentrations (|jg/L) in Groundwater 1.4 (Laboratory Reporting Limit) 1 5 (MCL) £3 CSSA Boundary Plume 1 Plume 2 CAMP BULLIS 0.5 Miles Figure 3: Plume Location Map CSSA Statement of Basis Page | 4 March 24, 2015 ------- Statement of Basis, Camp Stanley Storage Activity NW SE Segovia / Formation y Not present at CSSA. Fort Terrett Formation w ® Upper 2 9. Member j I Lower Member O & -o Cow Creek Limestone Hammett Shale Sligo Fm. Hosston Figure 4: Generalized Stratigraphic and Hydrostratigraphic Section of the Hill Country Area Texas regulations. With TCEQ and USEPA over- sight, a total of 84 sites, including 39 SWMUs, 41 AOCs, and five RMUs, were identified at CSSA. Investigations and interim removal actions (if warranted) were conducted at a total of 83 of these sites. One RMU, the location of CSSA's current active firing range, will be investigated when it is closed. Today, 77 sites have either been delisted or closed to residential land use standards in accordance with TCEQ require- ments. Four munitions SWMUs (B-2, B-8, B- 20/21, and B-24) have been combined with RMU- 1 because they are located within the active firing range where munitions continue to be tested. These sites will be investigated and remediated as necessary when the range is no longer active. The two remaining open sites at CSSA, SWMU B-3 and AOC-65, are the remaining sources of groundwater contamination, and will be the focus of future remediation efforts. Treatability studies to address the remaining open sites were initiated in 1996 (SWMU B-3) and 2002 (AOC-65) and continue to present day. Throughout the site clo- sure and treatability study process, USEPA and TCEQ have actively participated in planning, re- view, and approval. SITE GEOLOGY AND HYDROGEOLOGY CSSA is characterized by a rolling terrain of hills and valleys in which nearly flat-lying limestone formations have been eroded and dissected by streams draining to the east and southeast. CSSA is situated over Cretaceous-age deposits of the Travis Peak and Glen Rose Formations of the Trinity Group (Figure 4). Faulting has occurred near the central area and southern boundary of the installation. The faults are northeast-southwest trending, but most are not as continuous as the fractures. Soil cover is relatively thin, and bedrock is frequently exposed in most areas other than stream valleys (Figure 5). Topographic relief across the area ranges from about 1,100 to 1,500 feet above sea level. Groundwater occurrence and movement is highly variable due to the faulting and fractures in the limestone. Three aquifers are present in the area of CSSA: the Upper, Middle, and Lower Trinity aquifers. The Glen Rose Formation and the Travis Peak and Pearsall Formations are the principle water-bearing units. The primary groundwater source at CSSA and surrounding areas is the Middle Trinity aquifer, consisting of the Lower Glen Rose (LGR) Limestone, the Bexar Shale (BS), and the Cow Creek (CC) Limestone. The Middle Trinity aquifer supplies drinking water to CSSA and neighboring landowners and communities. In the vicinity of CSSA, the LGR portion of the Middle Trinity aquifer is recharged by direct precipitation on the outcrop and stream flow infiltration. Groundwater depth at CSSA averages approximately 200-250 feet below the ground surface, though the depth can vary significantly with precipitation, drought, and topographic location. CSSA Statement of Basis Page | 5 March 24, 2015 ------- Statement of Basis, Camp Stanley Storage Activity 2200 2100 2000 1900 1800 1700 1600 1500 1400 1300 1200 1100 o 1000 > 900 _Q) LU 800 700 600 500 400 300 200 | 100 Sea Level -100 -200 -300 -400 Kendall County Edwards Group Bexar County Camp Stanley Storage Activity (approximate location) Edwards Group Lower Glen Rose Limestone Hansel Sand — D Bexar Shale -^^LgreekLimeston, Shale St°n Sana Travis Peal Formation I ¦ "erer>tiaied Sligo Limestone Bexar Shale Cow Creek Limestone Hammett Shale Sligo Limestone Hosston Sand ~ 3 6 Miles 6 Kilometers Lower Glen Rose Limestone Bexar Shale Cow Creek Hammett Shale Sligo Limestone Hosston Sand Bexar Shale —(-». Cow Creek Limestone , Hammett Shale Sligo Limestone - Hosston Sand - 600 550 500 450 400 350 ^ 300 § CD 250 200 150 100 50 Sea Level -50 -100 Figure 5: Geologic Cross-section through the CSSA Area The Upper Trinity aquifer consists of the Upper Glen Rose (UGR) Limestone. Recharge to the Upper Trinity aquifer is from direct precipitation to UGR Limestone outcrop and from stream flow infiltration. Regionally groundwater flows to the south-southeast, with local variability depending on faults, fractures, and other pumping wells. FACILITY INVESTIGATION The Order requires CSSA to: (1) perform interim/stabilization measures (IM) at the facility to prevent or minimize the further migration of contaminants due to releases of hazardous constituents to the environment, or to mitigate current or potential threats to human health or the environment; (2) perform an RFI to determine the nature and extent of any release(s) of hazardous waste or hazardous constituents at or from the facility; (3) create a CMS to identify and evaluate alternatives for corrective action(s) to prevent or mitigate any migration of release(s) of hazardous wastes or hazardous constituents at or from the facility, and to collect any other information necessary to support the selection of corrective measures at the facility; and (4) implement the corrective measures (Corrective Measure Implementation [CMI]) selected by USEPA for the facility (Figure 6). Figure 6: RCRA Corrective Action Process CSSA Statement of Basis Page | 6 March 24, 2015 ------- Statement of Basis, Camp Stanley Storage Activity INTERIM MEASURES The following I Ms were completed at CSSA: Waste site closures. Between 1999 and 2014, in- vestigations and removal of soil (if warranted) were conducted at 83 identified waste sites. A to- tal of 77 sites were closed to TCEQ's residential land use standards. Two sites with groundwater contamination remain open, and four additional SWMUs were combined with RMU-1 as they are part of the active firing range. On- and Off-Post Groundwater Monitoring and In- stallation of Point-of-Use Treatment Units. Groundwater monitoring has been conducted at CSSA since 1991. Quarterly sampling of both on- and off-post wells began in 1999. Scheduled groundwater monitoring continues as part of the RFI task. All private groundwater wells with sol- vents present at concentrations greater than 90 percent of the MCL have been equipped with granular activated carbon (GAC) units to prevent exposure to contaminated groundwater. RCRA FACILITY INVESTIGATION Under the Order, CSSA performed an RFI to characterize soil and groundwater contamination, identify and evaluate associated hazards and risk(s), and provide documentation supporting necessary corrective action planning for CSSA (Parsons 2014b). As previously described under Regulatory History, CSSA closed 77 sites under State of Texas regulations, with both TCEQ and USEPA oversight since the Order was issued in 1999. The two remaining open sites that were further evaluated in the RFI are AOC-65 and SWMU B-3 (Figure 2). Contamination from past disposal activities resulted in multiple groundwater units, referred to as Plume 1 (SWMUs B-3 and 0-1) and Plume 2 (AOC-65) as shown on Figure 3. Waste and contaminated soil at SWMUs B-3 and 0-1 have been removed. (These two sites are lo- cated next to each other and were the source of groundwater contamination in Plume 1.) Due to its proximity to SWMU B-3, groundwater at SWMU 0-1 was evaluated as part of the SWMU B-3 investigation. Plume 1 has migrated primarily south-southeast toward Camp Bullis. A compo- nent of the plume has also migrated west-south- west. VOC concentrations over 500 micrograms per liter (jjg/L) are present in Middle Trinity aqui- fer wells near the source area. In contrast, little to no contamination within the deeper BS and CC Limestone has been identified within Plume 1 ex- cept in association with open borehole well com- pletions. Contamination at Plume 2 originated at AOC-65, and spread southward and westward. The great- est concentrations of solvents are reported in the subsurface adjacent to the source area, nearby a maintenance building where solvents were used. Concentrations greater than 100 |jg/L have been reported in perched groundwater zones above the main aquifer body in the LGR. Below the perched intervals, within the shallower portions of the Middle Trinity aquifer, VOC concentrations are generally less than 100 |jg/L. The deeper, more productive portion of the Middle Trinity aq- uifer has had only sporadic trace level contami- nant concentrations. Off-post, concentrations above MCLs have been detected in private and public wells with open borehole completions. All private groundwater wells with solvents present at concentrations greater than 90 percent of the MCL have been equipped with GAC units and wells in the area are monitored quarterly. SUMMARY OF RISK ASSESSMENT Based on the results of the 2013 human health risk assessment (HHRA), which evaluated samples collected before GAC treatment, unacceptable risks to human health could potentially occur in some locations off-post from exposure to contaminants in untreated groundwater at CSSA (Parsons 2014a). Cumulative carcinogenic risks greater than the USEPA acceptable range were calculated in several off-post wells. The highest cumulative carcinogenic risk calculated using the Protective Concentration Limits (PCLs) was in well RFR- 10, while the highest cumulative carcinogenic risk calculated using the regional screening levels (RSLs) was in well LS-5. Private wells with VOC concentrations greater than 90% of the MCL have been equipped with a GAC treatment unit. Unacceptable risks to human health could potentially occur in some locations on-post from exposure to contaminants in untreated CSSA Statement of Basis Page | 7 March 24, 2015 ------- Statement of Basis, Camp Stanley Storage Activity groundwater at CSSA. There are several locations on-post with cumulative non- carcinogenic hazards greater than 1. The highest cumulative hazard was calculated in well CS-9, a former water supply well that will be plugged and abandoned in 2015. Additionally, cumulative carcinogenic risks greater than the USEPA acceptable level were calculated in several on-post wells. The highest cumulative carcinogenic risk was calculated within the LGR geologic unit of Westbay monitoring well CS-WB05-LGR. In 2007, six new LGR wells (CS-MW20-LGR through CS-MW25-LGR) were drilled at CSSA. The initial sampling results in June 2007 indicated the presence of mercury, chromium, and lead in three of these wells (CS-MW22-LGR, CS-MW23- LGR, and CS-MW25-LGR). The notable trend of these particular wells is that inorganic constituents in groundwater have attenuated within a year of their initial sampling event in June 2007. With the exception of a single detection of lead above the action level in December 2010, this set of wells has not exceeded regulatory thresholds since March 2008 (Parsons 2014b). Lead hazards (e.g., non-carcinogenic hazards) greater than 1 were calculated for four on-post wells. The hazards ranged from 2 to 13. Where the risk assessment identified a non-carcinogenic hazard due to lead concentrations, a correlation with historic lead-containing well piping and pumps is suspected based on the timing of the detections after well maintenance activities. Two of the wells where lead was detected are former water supply wells, CS-9 and CS-11, which will be abandoned in 2015 and have not been used for water supply since 2008 (CS-9) and 1999 (CS-11). Past lead exceedances in water supply well CS-1 were sporadic after well maintenance activities, and in 2011, the well was rehabilitated with new materials. Since December 2011, lead levels in all samples have been below the action level. CORRECTIVE MEASURES STUDY Under the Order, CSSA performed a CMS to screen and develop corrective measures alternatives for removal, containment, treatment, and/or other remediation of groundwater contamination identified at SWMU B-3 and AOC- 65 (Parsons 2014c). Corrective Action Objectives (CAOs) were developed to identify CSSA's goals for reducing hazards to ensure protection of human health, safety, and the environment. The CAO for soil at CSSA was to clean up contaminated soil at each site to Tier 1 or Tier 2 TCEQ Residential PCLs. All soil at identified SWMUs, AOCs, and RMUs at CSSA was remediated to residential PCLs with the exception of RMU-1. RMU-1 will be remediated and closed when the range is no longer active. CAOs for groundwater at CSSA include: 1. Prevent or minimize migration of COCs in ground water within the source area at concentrations exceeding the MCLs and restore groundwater to its most beneficial use in a reasonable timeframe. 2. Prevent human exposure to groundwater containing COCs at concentrations that exceed MCLs in water supply wells. 3. Prevent on-site worker dermal contact and/or ingestion of COCs in shallow groundwater at concentrations exceeding acceptable human health risk values. All potential technologies that may be used to achieve the CAOs were identified and preliminarily evaluated for potential further consideration as part of corrective measures alternatives (CMAs). Upon consideration of various containment technologies, four CMAs were developed and evaluated to address groundwater contamination at CSSA: Alternative 1 - No Action. No corrective measures will be implemented to reduce the exposure to contaminated groundwater at CSSA, and would involve continued use of the site in its current condition. This alternative is provided as a baseline against which other CMAs can be compared. Alternative 2 - Point-of-Use Treatment. Land Use Controls (LUCs). and Long-Term Monitoring (LTM). Implement institutional and engineering LUCs to prevent contact with contaminated media. CSSA Statement of Basis Page | 8 March 24, 2015 ------- Statement of Basis, Camp Stanley Storage Activity Current off-post point-of-use treatment systems (GAC units) would continue to be operated and monitored. New GAC units would be installed at additional off-post drinking water wells if COC concentrations exceeding the MCLs are detected during the long-term monitoring program. Any reduction in plume or source area contaminant concentrations would occur only through natural attenuation processes, and would be monitored as part of the LTM program. Alternative 3 - Source Area Treatment. Alternative Drinking Water Source. Land Use Controls, and Long-Term Monitoring. Implement institutional and engineering LUCs to prevent contact with contaminated media. Off-post groundwater users supplied with drinking water from San Antonio Water System (SAWS). Continued use of bioremediation (bioreactor) to treat the source area at SWMU B-3. Continued use of in situ chemical oxidation (ISCO) to treat source area contamination at AOC-65. Alternative 4 - Source Area Treatment. Point-of- Use Treatment, Land Use Controls, and Long- Term Monitoring. Implement institutional and engineering LUCs to prevent contact with contaminated media. Current off-post GAC units would continue to be operated and monitored. New GAC units would be installed at additional off-post drinking water wells if COC concentrations exceeding the MCLs are detected during the long-term monitoring program. Continued use of bioremediation (bioreactor) to treat the source area at SWMU B-3. Continued use of ISCO to treat source area contamination at AOC-65. EVALUATION OF CORRECTIVE MEASURES ALTERNATIVES In compliance with the Order, each alternative is evaluated according to the USEPA (1994 and 1999) criteria listed in Table 1. Alternative 1: No Action Cost Capital Cost $0 30-Year O&M Cost $0 30-Year Total Cost $0 30-Year Total Present Value $q Alternative 1 must be ruled out because it is not protective of human health, does not achieve the CAO, is not effective over the long-term, and does not reduce the toxicity, mobility, and vol- ume (TMV) of wastes. Alternative 2: Point-of-Use Treatment, Land Use Controls, and Long-Term Moni- toring Cost Capital Cost $1,300 30-Year O&M Cost $16.4M 30-Year Total Cost $22.1M 30-Year Total Present Value $n.5M Alternative 2 is protective of human health and the environment, complies with applicable waste management standards, and provides both short- and long-term effectiveness for the protection of human health. It would attain media cleanup standards; however, Alternative 2 relies only on natural attenuation to degrade contamination in the groundwater, and therefore would take a longer time to achieve those standards. Reduc- tion of TMV is similar to attainment of cleanup standards in that Alternative 2 would take a longer time to reduce TMV in groundwater than active remedial technologies. Alternative 2 is eas- ily implementable since all of the elements for these alternatives are already in place at CSSA, and it address CSSA's desire to choose environ- mentally sustainable remedial alternatives in that they utilize several best management practices (BMPs) of Green Remediation (USEPA 2008). Alternative 2 achieves two of the CAOs (prevent human ingestion and control on-post exposure to contaminated groundwater); however, it does not directly achieve the CAO of controlling the source areas and preventing migration of groundwater contamination within a reasonable timeframe. Alternative 3: Source Area Treatment, Al- ternative Drinking Water Source, Land Use Controls, and Long-Term Monitoring Cost Capital Cost $4.6M 30-Year O&M Cost $37.9M 30-Year Total Cost $55.8M 30-Year Total Present Value $26.3M CSSA Statement of Basis Page | 9 March 24, 2015 ------- Statement of Basis, Camp Stanley Storage Activity Alternative 3 is protective of human health and the environment, complies with applicable waste management standards, and provides both short- and long-term effectiveness for the protection of human health. Alternative 3 would also attain me- dia cleanup standards. The remedial methods employed by Alternative 3 (bioremediation and ISCO) are already reducing TMV at SWMU B-3 and AOC-65 at CSSA, and would continue to do so effectively in the future. Alternative 3 is difficult to implement both technically, logistically (as the U.S. government cannot force private well own- ers to abandon their wells), and administratively. Alternative 3 does not utilize BMPs of Green Re- mediation (USEPA, 2008) because the area dis- turbed for the SAWS conversion is extensive, and significant resources are utilized. Alternative 4: Source Area Treatment, Point-of-Use Treatment, Land Use Con- trols, and Long-Term Monitoring Cost $693,500 Capital Cost 30-Year O&M Cost $38.8M 30-Year Total Cost $52.8M 30-Year Total Present Value $23.5M Alternative 4 is protective of human health and the environment, complies with applicable waste management standards, and provides both short- and long-term effectiveness for the protection of human health. Alternative 4 would also attain me- dia cleanup standards. The remedial methods employed by Alternative 4 (bioremediation and ISCO) are already reducing TMV at SWMU B-3 and AOC-65 at CSSA, and would continue to do so effectively in the future. Alternative 4 is easily implementable since all of the elements for these alternatives are already in place at CSSA. Alter- natives 4 also address CSSA's desire to choose environmentally sustainable remedial alterna- tives in that they utilize several BMPs of Green Remediation (USEPA 2008). Table 1 Evaluation Criteria for Corrective Measures Alternatives Overall Protectiveness of Human Health and the Environment determines whether an alternative adequately protects hu- man health and the environment from unacceptable risks posed by contamination in both the short- and long-term. Attain Media Cleanup Standards evaluates whether the alternative meets federal and state environmental statutes, regula- tions, and other requirements that pertain to the site, or whether a waiver is justified. Control the Sources of Releases addresses the issue of whether source control measures are necessary, and if so, the type of actions that would be appropriate. Comply with Any Applicable Standards for Management of Waste includes a discussion of how the specific waste man- agement activities will be conducted to comply with all applicable state or federal regulations (e.g., closure requirements, land disposal restrictions). Long-term Reliability and Effectiveness considers the ability of an alternative to maintain protection of human health and the environment over time. Reduction of Toxicity, Mobility, and Volume (TMV) of Waste evaluates use of treatment to reduce harmful effects of princi- pal contaminants, their ability to move in the environment, and the amount of contamination present. Short-term Effectiveness considers the length of time needed to implement an alternative and the risks the alternative poses to workers, residents, and the environment during implementation. Implementability considers the technical and administrative feasibility of implementing the alternative, including factors such as the relative availability of goods and services. Cost Estimate includes estimated capital and annual operations and maintenance costs for a 30-year period, as well as pre- sent worth cost. Cost estimates are expected to be accurate within a range of +50 to -30 percent. Public Involvement considers whether the local community agrees with CSSA's analyses and preferred alternative. Com- ments received on the Statement of Basis are an important indicator of community acceptance. Sustainability addresses CSSA's goal of utilizing "Green" environmental remediation practices. CSSA Statement of Basis Page | 10 March 24, 2015 ------- Statement of Basis, Camp Stanley Storage Activity Table 2 Detailed Analysis of Corrective Measures Alternatives Criteria Alternative 1 No Action Alternative 2 Point-of-Use Treatment, Land Use Controls, and Long-Term Monitoring Alternative 3 Source Area Treatment, Alternative Drinking Water Source, Land Use Controls, and Long-Term Monitor- ing Alternative 4 Source Area Treatment, Point-of-Use Treatment, Land Use Controls, and Long-Term Monitoring 1. Protective of Human Health and the Environment No Yes Yes Yes 2. Attain Media Cleanup Standards Yes, but will take an unac- ceptably long time. Yes, but will take an unaccept- ably long time. Yes Yes 3. Control the Sources of Releases No No Yes Yes 4. Comply with Any Applicable Standards for Management of Wastes Not applicable, no waste generated. Not applicable, no waste gen- erated. Yes Yes 5. Long-Term Reliability and Effec- tiveness No Yes Yes Yes 6. Reduction in the Toxicity, Mobil- ity, or Volume of Wastes No No Yes Yes 7. Short-Term Effectiveness No Yes Yes Yes 8. Implementability Technically feasible, but may not be administra- tively implementable given potential unacceptable risks. Easily implementable as all el- ements of this alternative are already in place. Difficult to implement both techni- cally and administratively. Requires extensive off-post work including concurrence with multiple landown- ers, municipalities, and agencies. Easily implementable as all elements of this alternative are already in place. 9. Cost Estimate Capital 30-Year Annual O&M Total Present Value $0 $0 $0 $1,300 $16,443,984 $11,497,901 $4,594,915 $37,927,568 $26,273,737 $693,559 $38,804,837 $23,489,660 10. Sustainability Not applicable. Utilizes Best Management Practices (BMPs) of Green Re- mediation Does not utilize BMPs of Green Re- mediation because the area dis- turbed is extensive and significant resources are utilized. Utilizes BMPs of Green Re- mediation CSSA Statement of Basis Page | 11 March 24, 2015 ------- Statement of Basis, Camp Stanley Storage Activity PREFERRED ALTERNATIVE Alternative 4 (Source Area Treatment, Point- of-Use Treatment, LUCs, and LTM) is recom- mended for implementation because it achieves the CAOs, achieves the highest reduction in TMV, and is effective over the short- and long- term. While Alternative 2 is estimated to be less costly, it does not meet all of the CAOs within a reasonable timeframe. Alternative 3 meets the CAOs, but is difficult to implement both techni- cally, logistically, and administratively. COMMUNITY PARTICIPATION USEPA invites the public to review the Adminis- trative Record (Environmental Encyclopedia) in order to gain a more comprehensive understand- ing of the RCRA investigation and corrective measures activities that have been conducted at the Facility. The Environmental Encyclopedia is available for review online at http://www.stan- lev.armv.mil/index.htm, and at the following loca- tions: San Antonio Public Library 600 Soledad Street San Antonio, TX 78205-1208 (210) 207-2500 Mon. - Thur. - 9:00 a.m. to 9:00 p.m. Fri. & Sat. - 9:00 a.m. to 5:00 p.m. Sun. - 11:00 a.m. to 5:00 p.m. Patrick Heath Public Library 451 N. Main Boerne, TX 78006 (830) 249-3053 Mon. - Thur. - 9:00 a.m. to 7:00 p.m. Fri. - 9:00 a.m. to 6:00 p.m. Sat. - 10:00 a.m. to 4:00 p.m. USEPA welcomes public review and comment on all of the remedial alternatives described in this document and on any additional options not pre- viously identified and/or studied. Public input on all potential remedial alternatives, and on the in- formation that supports the alternatives, is an im- portant contribution to the remedy selection pro- cess. USEPA may modify the proposed remedy or select another remedy based on new and/or substantive information presented to USEPA through public comments. Therefore, the public is encouraged to review and comment on all alter- natives. The public comment period for the Statement of Basis begins April 8, 2015, and ends on May 8, 2015. During the public comment period, written comments must be postmarked or emailed by May 8, 2015, submitted to: lyssy.gregory@epa.gov or: U.S. Environmental Protection Agency New Mexico - Federal Facilities Section (6PD-F) Attention: Greg Lyssy 1445 Ross Avenue Dallas, Texas 75202 USEPA will also hold a public meeting beginning at 6:30 pm on April 23, 2015, to inform the com- munity about the proposed remedy. The public meeting will be held at the following location: Leon Springs Baptist Church 24133 Boerne Stage Road San Antonio, TX 78255 USEPA will address all comments received dur- ing the public comment period in the Response to Comments/Final Decision document (RTC). The RTC will explain USEPA's rationale for the rem- edy selected to address contamination at CSSA. The preferred remedy in the Statement of Basis is a preliminary determination. Should another option be selected as the remedy based upon public comment, new information, or a re-evalua- tion of existing information, any significant differ- ences from this Statement of Basis will be ex- plained in the RTC. The RTC will be incorporated into the Administrative Record and made availa- ble to the public in the information repositories. The final remedy selected by USEPA will be im- plemented through the CM I phase in the correc- tive action process, as outlined in the USEPA Or- der. CSSA Statement of Basis Page | 12 March 24, 2015 ------- Statement of Basis, Camp Stanley Storage Activity REFERENCES Parsons 2014a. Baseline Risk Assessment. Prepared for Camp Stanley Storage Activity, Boerne, Texas. January. Parsons, 2014b. RCRA Facility Investigation Report for Camp Stanley Storage Activity. Prepared for Camp Stanley Storage Activity, Boerne, TX by Parsons. August. Parsons, 2014c. Corrective Measures Study Report for Camp Stanley Storage Activity. Prepared for Camp Stanley Storage Activity, Boerne, TX by Parsons. October. USEPA, 1994. RCRA Corrective Action Plan - Fina\. Office of Solid Waste and Emergency Response, Washington, DC. May. Available online: http://www.epa.qov/epawaste/hazard/correctiveaction/resources/quidance/qen ca/rcracap.pdf USEPA, 1999. Administrative Order on Consent. Docket No. RCRA-VI 002(h)99-H FY99. In the Matter of: Camp Stanley Storage Activity, Boerne, Texas, United States Environmental Protection Agency, May. USEPA, 2008. Green Remediation: Incorporating Sustainable Environmental Practices into Remediation of Contaminated Sites. Available online: http://ne- pis.epa.qov/Exe/ZvPURL.cqi?Dockev=P1000NZ3.txt CSSA Statement of Basis Page | 13 March 24, 2015 ------- Statement of Basis, Camp Stanley Storage Activity GLOSSARY OF TERMS Administrative Order on Consent - A legal agreement issued by USEPA and signed by USEPA and potentially responsible parties (PRPs). It contains the details of a settlement whereby PRPs will conduct all or part of the cleanup at a site. It may be subject to a public comment period, and is enforceable in court. An administrative order on consent does not have to be approved by a judge. CSSA's Administrative Record is available at http://www.stanlev.armv.mil/. Administrative Record - An administrative record is the complete body of documents that forms the basis for selecting a RCRA corrective action (i.e., documents considered or relied upon in selecting a remedy). The administrative record acts as a vehicle for public participation in selecting a response action because the administrative record must be made available for public inspection and comment during the appropriate comment periods. Aquifer - A saturated geologic unit, often of sand or gravel, which contains and transmits significant quan- tities of water under normal conditions. Area of Concern (AOC) - AOCs are those sites where field investigations and/or historical aerial photo- graph research indicate a possibility that waste disposal activities or spills may have taken place, as evi- denced by disturbed areas, exposed surface debris, or detection of contamination. Best Management Practices (BMPs) - Methods, measures, or practices that are determined to be rea- sonable and cost-effective means for a land owner to meet certain, generally nonpoint source, pollution control needs. BMPs include structural and nonstructural controls, and operation and maintenance proce- dures. Bioremediation - Techniques using biological processes to treat contaminated soil or groundwater. Bio- remediation can occur either in situ or in bioreactors where contaminated media are placed in contact with organisms to degrade the contaminants in a controlled environment. Generally, the technique involves stimulating organisms by adding materials such as nutrients or oxygen to increase the rate of biodegrada- tion. Carcinogenic - Describes a substance that causes or is likely to cause cancer. Conceptual Site Model - A planning tool that provides the framework from which a study design is struc- tured. It is frequently created as a site map that organizes information that already is known about a site. Corrective Action Objective (CAO) - Site-specific objectives that support the performance standards. They are medium-specific (e.g., soil or groundwater) and must be linked to a cleanup standard in order to measure remedy performance. Corrective Measure Implementation (CMI) - The process of designing, constructing, operating, main- taining, and monitoring the corrective remedy approved by the regulator on the basis of the information presented in the CMS. Corrective Measures Study (CMS) - The objective of a CMS is to identify and evaluate alternative cor- rective measures and to recommend a corrective measure(s) for remediation of the contaminated site. To achieve this objective, the CMS considers all of the necessary data and information to evaluate the pro- posed alternatives. Exposure - Human contact with a physical, chemical, or biological agent through dermal absorption, inhalation, injection, or ingestion. Human Health Risk Assessment (HHRA) - Qualitative and quantitative evaluation of the risk posed to human health by the actual or potential presence of specific contaminants. CSSA Statement of Basis Page | 14 March 24, 2015 ------- Statement of Basis, Camp Stanley Storage Activity In Situ Chemical Oxidation (ISCO) - ISCO involves the introduction of a chemical oxidant into the sub- surface for the purpose of transforming groundwater or soil contaminants into less harmful chemicals. Interim/Stabilization Measures (IM) - Under RCRA, interim/stabilization measures are the recom- mended actions that are used to quickly control risk of exposure to, or limit further migration of, contami- nation at a site. Maximum Contaminant Level (MCL) - The maximum permissible level of a contaminant in water that is delivered to any user of a public water system. Non-Carcinogenic Hazard - A number indicating whether a non-carcinogenic hazard is possible from a given concentration of a certain pollutant or group of pollutants. A hazard below 1.0 indicates that an effect is unlikely, while 1.0 or above indicates the possibility of an effect. Phosphate-Induced Metal Stabilization (PIMS) - A technology that uses an Apatite II material (made from processed fish bones and other fish hard parts) that chemically binds metals into stable, insoluble minerals. PIMS works in all types of soils and groundwater, under most pH and environmental conditions, and at all contaminant concentrations. Protective Concentration Limit (PCL) - Cleanup levels that are protective of human health and the en- vironment as set forth by the TCEQ Texas Risk Reduction Program. Range Management Unit (RMU) - An area currently or formerly occupied by a munitions range. RCRA Facility Investigation (RFI) - The RFI takes place when releases, or potential releases, have been identified and further investigation is necessary. The purpose of the RFI is to gather enough data to fully characterize the nature, extent, and rate of migration of contaminants to determine the appropriate re- sponse action. Regional Screening Level (RSL) - Screening developed using risk assessment guidance from the USEPA Superfund program that can be used for Superfund sites. They are risk-based concentrations derived from standardized equations combining exposure information assumptions with USEPA toxicity data. RSLs are considered by USEPA to be protective for humans (including sensitive groups) over a lifetime. Residential Land Use - Property used for dwellings such as single family houses and multi-family apart- ments, children's homes, nursing homes, and residential portions of government-owned lands. Because of the similarity of exposure potential and the sensitive nature of the potentially exposed population, day care facilities, educational facilities, hospitals, and parks are also considered residential. Resource Conservation and Recovery Act (RCRA) - A federal law intended to protect human health and the environment from the potential hazards of waste disposal, conserve energy and natural resources, reduce the amount of waste generated, and ensure that wastes are managed in an environmentally sound manner. Solid Waste Management Unit (SWMU) - Includes any unit at a facility from which hazardous constitu- ents might migrate irrespective of whether the units were intended for the management of solid and/or hazardous waste. Toxicity, Mobility, and Volume (TMV) - Degree to which an alternative reduces (1) the harmful nature of the contaminants, (2) their ability to move through the environment, and (3) the amount of contamination at the site Volatile Organic Compound (VOC) - An organic (carbon-containing) compound that evaporates (volati- lizes) readily at room temperature. CSSA Statement of Basis Page | 15 March 24, 2015 ------- Statement of Basis, Camp Stanley Storage Activity ACRONYMS AND ABBREVIATIONS AOC Area of Concern BFZ Balcones fault zone BMP best management practices BS Bexar Shale CAO corrective action objectives CC Cow Creek CMA Corrective measures alternatives CMI Corrective Measures Implementation CMS Corrective Measures Study CSM conceptual site model CSSA Camp Stanley Storage Activity GAC granular activated carbon HHRA human health risk assessment IH Interstate Highway IM Interim/stabilization measures ISCO in situ chemical oxidation LGR Lower Glen Rose LTM Long-Term Monitoring LUC Land Use Controls MCL Maximum contaminant level mq/l Micrograms per liter Order Administrative Order on Consent PCE Tetrachloroethene PCL Protective Concentration Limits PIMS phosphate-induced metal stabilization RCRA Resource Conservation and Recovery Act RFI RCRA Facility Investigation RMU Range Management Unit RSL regional screening level RTC Response to Comments SAWS San Antonio Water System SWMU Solid Waste Management Unit TCE Trichloroethene TCEQ Texas Commission on Environmental Quality TDH Texas Department of Health TMV toxicity, mobility, and volume UGR Upper Glen Rose USEPA U.S. Environmental Protection Agency UU/UE unrestricted use/unrestricted exposure VOC Volatile organic compound CSSA Statement of Basis Page | 16 March 24, 2015 ------- Statement of Basis, Camp Stanley Storage Activity CAMP STANLEY STORAGE ACTIVITY - PUBLIC COMMENT PERIOD The 30-day public comment period for the Camp Stanley Storage Activity will begin on, April 8, 2015, and end on May 8, 2015. Your written comments must be postmarked or e-mailed by May 8, 2015. USEPA would like your comments on the Statement of Basis for Camp Stanley Storage Activity. Please write your comments below, then fold, tape, stamp, and mail this form. USEPA will address all comments received during the public comment period in the Response to Comments/Final Decision document (RTC). If you would like to receive a copy of the RTC, please state in your comments that you would like to receive the RTC and include your full name and address on the return address form. CSSA Statement of Basis Page | 17 March 24, 2015 ------- Statement of Basis, Camp Stanley Storage Activity CAMP STANLEY STORAGE ACTIVITY - PUBLIC COMMENT PERIOD RCRA CORRECTIVE ACTION PUBLIC COMMENT PERIOD The public comment period for Camp Stanley Storage Activity begins APRIL 8, 2015. Your comments must be post marked by May 8, 2015. Name: Address: City: State and Zip: U.S. EPA Attn: Greg Lyssy Senior Project Manager New Mexico - Federal Facilities Section Mail Code: 6PD-F 1445 Ross Avenue Dallas, TX 75202 CSSA Statement of Basis Page | 18 March 24, 2015 ------- |