November 1998 Engineering Evaluation/Cost Analysis for: Words in italics are defined in the glossary at the end of this fact sheet. They are only italicized the first time they are used. This fact sheet describes the removal action alternatives considered and the one preferred by the Air Force Center for Environmental Excellence (AFCEE) to address surface and subsurface soil contamination at several sites at the Massachusetts Military Reservation (MMR). The sites included in the Engineering Evaluation/Cost Analysis (EE/CA) are:
Project Managers from AFCEE, the U.S. Environmental Protection Agency (USEPA), and the Massachusetts Department of Environmental Protection (MADEP) will be evaluating alternatives to select the most appropriate solution for the contaminated soil at these sites. Public involvement during the decision-making period is critical to selecting an alternative that not only cleans up these sites and meets regulatory requirements, but also is acceptable to the affected communities.
This fact sheet provides an overview of the EE/CA, which is available for public comment from November 13 to December 12, 1998. The EE/CA contains:
The purpose of an EE/CA is to balance cost with technical concerns for each removal alternative under consideration. An EE/CA is completed for a removal action, which is a short-term response to a threat to public health, welfare, or the environment. Removal actions differ from remedial actions in that removals are generally more limited in scope and cost. After a public comment period on the EE/CA, AFCEE will consider the comments and select a removal action for each site. The decision will be documented in an Action Memorandum which presents the selected alternative, explains the rationale for the selection, and provides responses to comments and concerns raised during the public comment period. The EE/CA document contains more information about the sites, the contaminants detected, and the removal action alternatives. You are encouraged to read the EE/CA, attend the public meetings, ask questions, and offer comments. Your involvement in the decision-making process is critical and will enable the Remedial Project Managers from AFCEE, USEPA, and MADEP to select an alternative that is acceptable to the community.
Introduction In accordance with the federal Superfund law, an EE/CA may be conducted for identifying and evaluating cleanup alternatives for a site when there is a substantial threat to human health or the environment. The purpose of the EE/CA is to identify removal action objectives, to identify and evaluate removal action alternatives that may achieve those objectives, and to recommend, based on the evaluation, the alternative that best meets the USEPA evaluation criteria. Site investigations (SIs) for seven sites (Figure 1), carried out under the Installation Restoration Program, identified the presence of petroleum hydrocarbons, polynuclear aromatic hydrocarbons (PAHs), dieldrin, the polychlorinated biphenyl (PCB) Aroclor-1242, and inorganic compounds (e.g., lead, cadmium, chromium) in soil at concentrations that may pose an unacceptable risk to public health and/or the environment. Further analysis was conducted on these contaminants and the potential risks. Using that information, several action alternatives were developed and evaluated. After careful consideration of several alternatives, AFCEE believes the proposed actions comprising the preferred alternative will protect human health and the environment and will comply with applicable environmental laws and regulations. The EE/CA describes the various alternatives and presents AFCEE's preferred alternative.
Figure 1. Location of Study Areas Site Description and History CS-5 CS-5 is located at Building 3461 at the northeastern corner of Beaman and Weaver roads (Figure 2). From 1941 to 1946, the building was used by the U.S. Army as a weapons repair shop. Cosmoline, a rust-inhibitor containing petroleum hydrocarbons, was routinely removed from new weapons, reportedly using gasoline and/or kerosene. Cosmoline and the compounds used to remove it were potentially disposed of at CS-5. Reportedly, from 1955 to 1967, the U.S. Air Force (USAF) used Building 3461 as a refueler maintenance shop and spray paint shop. Other materials that reportedly may have been disposed of at the site include waste oils, solvents, paints, battery acid, and antifreeze. The site may also have been used as a salvage yard for some period of time. Investigations conducted at CS-5 show that surface soil contaminated with 17 parts per million (ppm) of Aroclor-1242 and up to 7650 ppm of lead may pose an unacceptable risk to human and ecological receptors. Concentrations of up to 106,600 ppm petroleum hydrocarbons also exist in surface soil at this site. Based on this information, the SI Report recommended a removal action for three areas at CS-5. The EE/CA estimated the volume of contaminated soil to be approximately 1,240 cubic yards. Of the excavated material to be removed, approximately half will be disposed off-site due to elevated concentrations of lead (at Area 1) and Arorclor-1242 (at Area 2).
Figure 2. Location of Site CS-5. CS-11 CS-11 consists of Building 1116 which was used by the Air National Guard (ANG) and the Army National Guard (ARNG) as a pesticide shop for storage and mixing of pesticides and herbicides (Figure 3). According to the records search, pesticides and herbicides were mixed on an asphalt pad on the eastern side of the building. Pesticides that spilled during mixing were reportedly washed off the edge of the pad onto the surrounding soil. No major pesticide spills were reported. Investigations conducted at CS-11 indicate that surface soil contaminated with up to 2.7 ppm of dieldrin may pose an unacceptable risk to human and ecological receptors. Inorganic compounds (e.g., cadmium at 5.3 ppb and lead at 276 ppm) detected in surface soil may also pose an unacceptable risk to ecological receptors. Based on this information, the SI Report recommended a removal action for three areas of soil east and south of Building 1116. The EE/CA estimated the volume of contaminated soil to be approximately 110 cubic yards.
Figure 3. Location of Site CS-11 FS-18 FS-18 was a World War II motor pool and fuel transfer site located off North Gaffney Street, on the northwestern side of MMR (Figure 4). According to the records search, four underground storage tanks (USTs) were installed in 1941. Two contained diesel fuel and two contained motor gasoline. Because two of the tanks failed leak-testing, all four tanks were reportedly emptied and removed in 1985. Investigations conducted at FS-18 indicate concentrations of petroleum hydrocarbons of up to 5600 ppm south of North Gaffney Street in the drainage course which receives stormwater runoff from FS-18. Based on this information, the SI Report recommended a removal action for an area of surface and shallow subsurface soil (i.e., up to six feet below ground surface) in the drainage course. The EE/CA estimated the volume of contaminated soil to be approximately 230 cubic yards.
Figure 4. Location of Site FS-18 CS-4 (USCG)/FS-1 (USCG) CS-4 (USCG)/FS-1 (USCG) is located north of Riley Street (Figure 5). This site includes Hangar 128 and the surrounding area, located inside the security gate in the flightline restricted area. Hangar 128 was used to maintain EC-121 aircraft owned by the USAF, and later used by the USCG to maintain fixed-wing aircraft. According to the records search, periodic spills of waste oils and solvents occurred inside and outside the hangar. Additionally, two spills of aviation gasoline (AVGAS) occurred at the hangar in 1978, approximately 1,000 gallons on the northern side of the hangar, and between 200 and 300 gallons on the southern side of the hangar. These sites should not be confused with the CS-4 or FS-1 groundwater plumes, which come from different sources. Investigations conducted at the site indicate PAHs in soil at levels up to 141.3 ppm may pose an unacceptable risk to human and ecological receptors. Metals (i.e., cadmium, chromium, lead, zinc) detected in soil may also pose an unacceptable risk to ecological receptors. Based on this information, the SI Report recommended a removal action for an area of shallow soil (i.e., up to three feet below ground surface) on the eastern side of the taxiway leading from the northern side of Hangar 128. The EE/CA estimated the volume of contaminated soil to be approximately 560 cubic yards.
Figure 5. Location of Site CS-4 (USCG)/FS-1 (USCG). FS-4 FS-4 consists of an area surrounding the former Building 178, a fuel pumphouse, located on the base airfield (Figure 6). Six USTs were installed at the pumphouse in 1956. Four tanks were used to store AVGAS, one tank was a defueling tank, and the other tank was a collection tank. This site is within the restricted zone of the flightline and access can only be gained by authorized personnel. Investigations conducted at FS-4 indicate no unacceptable risk to human receptors from exposure to surface or subsurface soil, and only a slight potential risk to ecological receptors from polynuclear aromatic hydrocarbons (PAHs), dieldrin, and arsenic. In 1994, the pumphouse was demolished and the six USTs were removed. During the removal, residual fuel contamination was identified beneath the former collection and defueling USTs, at 10 feet and 22 feet below ground surface, respectively. Because the residual fuel contamination may pose a potential risk to human receptors, FS-4 was recommended to be included in the EE/CA. Based on additional soil sampling data to be collected during final design stages beneath the former USTs, additional soil may need to be removed to minimize potential risks to human receptors.
Figure 6. Location of Site FS-4. FS-7 FS-7 is located adjacent to the former Building 1820 on the northwest rotary (Figure 7). According to the records search, up to 11,000 gallons of fuel oil may have leaked from a UST installed in 1970, southwest of the former Building 1820. Records indicate the UST was removed in 1985; however, it is unclear whether soil around the tank was removed or placed back in the excavation after the tank removal. Investigations conducted at FS-7 indicate concentrations of PAHs (up to 23.5 ppm) in surface soil may pose an unacceptable risk to human and ecological receptors, so removal action is necessary. The EE/CA estimated the volume of contaminated surface soil to be approximately 15 cubic yards.
Figure 7. Location of Site FS-7. Drum Disposal Operable Unit (DDOU) The DDOU consists of a clearing in a wooded area located southeast of the former MMR sewage treatment plant (Figure 8). In 1994, 11 drums were observed in the area on the ground surface. The National Guard Bureau removed the drums, analyzed the contents, and disposed of them accordingly. Investigations at the DDOU indicate two areas of soil contamination that may pose an unacceptable risk to human and ecological receptors. The contaminants identified include primarily pesticides, several inorganic compounds (e.g., arsenic, chromium, lead) and some semivolatile organic compounds (SVOCs). The DDOU was recommended to be included in the EE/CA based on the high level of pesticides detected (e.g., up to 36,000 ppm of DDT) along with elevated levels of inorganic compounds and SVOCs. The EE/CA estimated the volume of contaminated soil to be approximately 740 cubic yards. A portion of this material may need to be disposed off-site due to the concentrations of pesticides detected.
Figure 8. Location of DDOU Why is Cleanup Needed at the Sites? Cleanup is necessary for these sites to remove contaminated soil to reduce and/or eliminate potential human and/or environmental exposure to the following compounds:
The following table summarizes the contaminants of concern, maximum concentrations detected, and estimated volume of contaminated soil at each site.
Cleanup Alternatives The EE/CA identified and evaluated the following three alternatives to reduce and/or eliminate exposure to contaminated soils: Alternative 1: On-base Thermal Desorption and/or Off-base Treatment and Disposal for six sites. In-situ Treatment was evaluated for FS-4. Alternative 2: On-base Asphalt Batching and/or Off-base Treatment and Disposal for six sites. In-situ Treatment was evaulated for FS-4. Alternative 3: Off-base Treatment and Disposal for six sites. In-situ Treatment was evaluated for FS-4. Each alternative involves excavating a total volume of approximately 2,900 cubic yards of surface soil (i.e., up to two feet below ground surface )and shallow subsurface soil (i.e., two to six feet below ground surface) from Study Areas CS-5, CS-11, FS-18, CS-4 (USCG)/FS-1 (USCG), FS-7, and the DDOU. Thermal Desorption: On-base thermal desorption is a process that uses indirect heat to vaporize and remove contaminants from the soil. The excavated soil is placed in a treatment unit where the soil is heated to 200 to 500 degrees Fahrenheit, depending on the type of contaminants being treated. The heat vaporizes the contaminants, and the vapors are collected and treated and clean air is discharged to the atmosphere. While this treatment process treats organic compounts very well, it does not effectively treat inorganic compounds. Therefore, soil contaminated with inorganic compounds will be shipped off-base to a permitted treatment and disposal facility. Asphalt Batching: On-base asphalt batching involves mixing the contaminated soil with an asphalt emulsion. The asphalt emulsion coats the soil particles and immobilizes the contaminants, thereby reducing exposure risk. The stable asphalt-emulsion-coated product can be used as a subbase for road paving projects. Air quality will be monitoring during the asphalt batching process, and operations adjusted as necessary. Asphalt batching has been successfully used as a treatment alternative at other MMR sites. State policies restrict the concentrations of certain contaminants that can be treated with the asphalt batching process. Therefore, the excavated soil will be tested before being mixed with the asphalt emulsion to confirm that the soil meets the policies. Any soil that does not meet these policies will be shipped off-base to a permitted treatment and disposal facility. In-Situ Treatment: The in-situ treatment technology evaluated in the EE/CA is in-situ low-flow soil vapor extraction. This system consists of installing pipes in the soil above the groundwater table and using a vacuum pump to remove air and organic vapors from the soil. The vapors removed from the soil are then treated to recover or destroy the contaminants. Off-Base Treatment and Disposal: Off-base treatment and disposal consists of loading the excavated soil into trucks and hauling the material off MMR property. The soil is sent to a permitted off-base facility where it is treated and/or disposed in accordance with appropriate state and federal regulations. The type of treatment process used is dependent upon the type of contaminants and the capabilities of the permitted facility. Analysis Approximately 70 to 75 percent of the excavated material would be treated on-base for both Alternatives 1 and 2. A small portion of the excavated material for both Alternatives 1 and 2 would likely need to be treated and disposed of off-base because it may not be acceptable for treatment at the on-base facilities. Additionally, some of the treated material from Alternative 1 may not meet the required soil target cleanup levels because thermal desorption does not effectively treat inorganic compounds. This material, as well as treatment process residuals, will need to be disposed of off-base. Therefore, the volume of material to be treated and/or disposed of off-base will likely be greater for Alternative 1 than for Alternative 2. For Alternative 3, all excavated soil from CS-5, CS-11, FS-18, CS-4 (USCG)/FS-1 (USCG), FS-7, and the DDOU would be treated and disposed of off-base. Additional sampling activities at FS-4 would focus on subsurface soil sampling and laboratory analysis to further evaluate the amount and distribution of contamination at the site. Implementation of the in-situ treatment system would be based upon results of the additional sampling. Laboratory analytical data would be used to design the system if it is part of the chosen alternative. AFCEE will present the additional sampling results and further recommendations for FS-4 to the public and regulatory agencies. Public involvement in the decision-making process will enable the Remedial Project Managers from AFCEE, USEPA, and MADEP to select an alternative that is acceptable to the community. How Does AFCEE Choose a Cleanup Plan? AFCEE uses the criteria developed by the USEPA, as presented in the NCP and the USEPA guidance on conducting EE/CAs. These criteria include effectiveness, implementability, and cost. Effectiveness considers:
Implementability considers:
Cost considers:
AFCEE's Preferred Alternative Based on the evaluation of removal action alternatives presented in the EE/CA, AFCEE’s preferred alternative is Alternative 2. This alternative includes excavating soil from the sites and treating the soil on-base using an asphalt batching facility. Some excavated soil may not be acceptable to be treated by the on-base treatment facility, because the concentrations of contaminants exceed the levels allowable by the state policies on this type of treatment process. This material, as well as treatment process residuals, will be shipped off-base to a permitted treatment and disposal facility. If additional sampling and analysis for FS-4 determines that subsurface soil requires treatment, an in-situ low-flow soil vapor extraction system will be implemented. Alternative 2 would be protective of human health and the environment, because asphalt emulsion binds the contaminants, thereby permanently reducing the mobility of contaminants. Additionally, any soil shipped off-base to a permitted treatment and/or disposal facility will reduce the potential for contaminant exposure and provide a reduction in contaminant mobility. Alternative 2 complies with federal and state environmental regulations and requirements, and can be easily implemented. This alternative would offer a reliable, effective, and permanent treatment option for the various site contaminants and is preferred over Alternative 1 because a smaller volume of soil will need to be shipped off-base for treatment and/or disposal (i.e., soil contaminated with inorganic compounds can be treated by asphalt batching but not by thermal desorption). Additionally, the stable asphalt-emulsion-coated product can be used as a subbase for road paving projects on MMR. This alternative is preferred over Alternative 3 because Alternative 3 has higher potential for risk during transportation of soils. The cost of Alternative 2 ($2,232,000) is essentially the same as Alternative 3 ($2,128,000) and would cost less than Alternative 1 ($3,599,000). Therefore, based on the evaluation of alternatives against the required criteria, AFCEE recommends Alternative 2, On-base Asphalt Batching and/or Off-base Treatment and Disposal with In-situ Treatment for FS-4, as the preferred alternative. AFCEE believes that this preferred alternative would satisfy the requirements of CERCLA Section 121 (b), that the selected alternative is protective of human health and the environment, complies with ARARs, is cost-effective, uses permanent solutions to the maximum extent practicable, and satisfies the statutory preference for treatment. For More Information More detailed information is available in the EE/CA. Copies of the EE/CA are available for review at the main libraries in Sandwich, Bourne, Mashpee, and Falmouth, at the U.S. Coast Guard library on base, and at the Installation Restoration Program office. For additional information, visit our website at http://www.mmr.org or call our Community Involvement Office at (508) 968-4678. For further information about the EE/CA, contact Bud Hoda at the Installation Restoration Program office, (508) 968-4670 x4918. Comments on the EE/CA can be submitted by using the comment page on the website or by sending a written comment postmarked by December 12, 1998 to:
A transcript of all formal comments and AFCEE's written responses will be provided in a Responsiveness Summary that will be included in a document called an Action Memorandum, which will be prepared in accordance with USEPA guidance documents. The Action Memorandum is a decision document that presents the selected removal action alternative, explains the rationale for the selection, and provides responses to public comments and concerns raised during the public comment period for the EE/CA. The Responsiveness Summary will be sent to everyone who submitted a formal comment. The Action Memorandum, including the Responsiverness Summary, will be placed in the Administrative Record. The Action Memorandum will also be available at the main libraries in the towns of Sandwich, Bourne, Mashpee, and Falmouth; at the U.S. Coast Guard library at MMR; and on the MMR website at http://www.mmr.org. In addition, AFCEE will announce the decision through the local news media and site mailing list. Action Memorandum: A decision document that presents the selected removal action alternative and explains the rationale for the selection. The Action Memorandum also includes responses to public comments and concerns raised during the public comment period. Administrative Record: A collection of documents generated during the investigation of the site placed in a central location for public review. Applicable or Relevant and Appropriate Requirements (ARARs): Federal and/or state environmental laws and regulations that must be met during the implementation and completion of remedial responses. Asphalt batching: A process that mixes contaminated soil with an asphalt emulsion. The asphalt emulsion coats the soil particles and immobilizes the contaminants, thereby reducing exposure risk. The stable asphalt-emulsion-coated product can be used as a subbase for road paving projects. Aviation gasoline (AVGAS): A gasoline used in airplanes. Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA): This law, commonly known as Superfund, authorizes the federal government to respond directly to releases of hazardous substances that may endanger public health or the environment. Cosmoline: A rust-inhibitor containing petroleum hydrocarbons Dieldrin: A pesticide used for killing insects. Engineering Evaluation/Cost Analysis (EE/CA): An expedited CERCLA process of identifying and evaluating cleanup alternatives for a site when there is a potential threat to human health or the environment. The EE/CA must be made available for a 30 calendar day public comment period prior to the signing of the Action Memorandum. Federal Facilities Agreement: An agreement between USEPA and individual federal facilities which establishes a procedural and legal framework for investigating and performing remedial actions at Superfund sites. Flightline: That portion of MMR, including runways, hangars, and adjacent areas, which directly supports aircraft operations. Inorganic compounds: A class of naturally occurring compounds that includes metals, cyanide, nitrates, sulfates, chlorides, carbonate, bicarbonate, and other oxide complexes. In-situ low-flow soil vapor extraction: Pipes are installed in the soil above the groundwater table. A vacuum pump is used to remove air and organic vapors from the soil. The vapors removed from the soil are treated to recover or destroy the contaminants. Installation Restoration Program: The Department of Defense program implemented at military bases to identify, investigate, and cleanup contamination resulting from past operations. National Oil and Hazardous Substances Pollution Contingency Plan (NCP): The federal regulation that guides the Superfund program. National Priorities List (NPL): The USEPA’s list of the most serious uncontrolled or abandoned hazardous waste sites. Petroleum hydrocarbons: Compounds common to petroleum products. Polychlorinated Biphenyls (PCBs): A group of toxic or persistent chemicals used in electrical transformers and capacitors for insulating purposes. Further sale or new use was banned by law in 1979. Polynuclear Aromatic Hydrocarbons (PAHs): A group of organic chemicals common to hydrocarbon fuel, but can also exist naturally in the environment. PAHs are found in high concentrations in urban or industrial areas, or near airports. Some PAHs are believed to cause cancer; others have not been observed to produce adverse health effects. Priority 2 and 3 Study Areas: Units defining the geographic extent of further investigation. At the initiation of the investigations of the IRP sites at MMR in 1985, a preliminary assessment, known as a records search, was conducted to identify areas of potential contamination. Records search results were used to prioritize the study areas at MMR, based on the potential to cause a threat to human health and/or the environment. Site investigations and supplemental sampling were conducted at these study areas and the Drum Disposal Operable Unit between 1989 and 1995. Based on the results of these investigations, seven sites were recommended for soil removal actions and are evaluated in the EE/CA. Five sites were recommended for remedial investigations/feasibility studies, and the remaining six sites were recommended for no further action. Removal Action: A short-term immediate action taken to address a release or threatened release of a hazardous substance. A hazardous substance is any material that poses a threat to public health and/or the environment. Typical hazardous substances are materials that are toxic, corrosive, ignitable, explosive, or chemically reactive. Responsiveness Summary: A document presenting formal comments received during the public comment period with written responses to those comments. Semivolatile Organic Compounds (SVOCs): A group of chemical compounds composed of carbon and hydrogen that will evaporate into the air, but less readily than volatile organic compounds. SVOCs include substances contained in fuels, resins, and some solvents. Site Investigation (SI): A technical phase of work that follows a preliminary assessment, or records search, designed to collect more extensive information on a potential hazardous waste site. The information is used to evaluate a site to determine whether further action is required. Thermal desorption: A process that uses indirect heat to vaporize and remove contaminants from the soil.
|
