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Site 11: Cantonment AreaSite History and Background
The Cantonment Area was built in the 1950s and served as the headquarters for the Makah AFS until the AFS was closed in 1988. Administrative activities and equipment maintenance took place in this area. During the time the Makah AFS was in operation, waste oil mixed with various hazardous wastes (e.g., gasoline, paint thinner, and occasionally dielectric transformer fluid, possibly containing PCBs) was burned at the open burn pit (Chamblin, 1994; Olson, 1994). Gasoline and diesel were stored in underground storage tanks at this site when the Makah AFS was active. Petroleum-contaminated soil was reportedly uncovered near the former tennis courts by members of the Tribe during a pipeline excavation.
A storage/paint shop (Building 44) was used to store paints, kerosene, oil, and paint-application equipment when the Makah AFS was active (Radian, 1987). A fenced-in enclosure (the "storage yard") was used to store PCB-containing transformers, discarded paints, and drums of used lubricating and motor oil. Outside of Building 44, paint containers were rinsed onto the bare ground, and the paint/solvent/water mixture ran overland toward a ditch on the southeast side of the shop (Radian, 1987). Pesticides/herbicides have been used throughout the Makah AFS and were stored in Building 43 when not in use. All application equipment was rinsed with wash water after use, and the wash water was collected in a concrete underground storage tank (designated UST-G) located 50 feet southeast of the paint shop. A hydraulic lift is located in the motor equipment repair shop. Used motor oil was formerly drained from vehicles into the concrete-lined pit associated with the lift. The pit is connected to a settling tank, which consists of an approximately 30-gallon drum in a concrete-lined pit located between Buildings 17 and 43. The hydraulic lift system may have underground piping that leads to the creek east of the site. Fish have been observed in the creek that flows through the east end of the site and into the Waatch River (Ridolfi, 2004a). Contaminants at this site have the potential to migrate to this creek. Activities to DateSeveral investigations and cleanup activities were conducted at the site under various DoD contracts in the late 1980s and early 1990s. The Makah Environmental Restoration Team inspected the site in October 2000, October 2002, April 2003, and March and April 2004; a limited remedial investigation was conducted in December 2002 and January 2003; a test pit investigation took place in December 2004; and additional ground water samples were collected in March 2006. DoD Investigations and Cleanup Activities
In 1987, prior to closure of the Makah AFS, a hazard evaluation was conducted by Radian for the USACE to identify environmental issues related to military activities at the site. This evaluation identified abandoned drums, pesticides, asbestos, PCBs, and ten underground storage tanks as potential concerns (Radian, 1987). In June 1988, Tetra Tech, Inc., conducted an asbestos and underground storage tank survey for the USACE, Seattle District. Potential asbestos-containing materials were inventoried and sampled; air monitoring for asbestos was conducted in four buildings to determine whether existing conditions pose health risks; nine underground storage tanks were surveyed; and a tank leak test was conducted on two of the underground storage tanks. The survey showed that much of the outdoor steam piping and many buildings contained friable asbestos-containing materials. All ambient air analysis results were below OSHA's permissible exposure level (Tetra Tech, 1988).
In 1988, following its field survey, Tetra Tech also prepared a statement of work for site cleanup that included the removal of asbestos-containing materials, five underground storage tanks, and all drummed containers and the collection of soil samples near UST-G (Tetra Tech, 1988). In 1989, the 25th Air Division at McChord Air Force Base requested that the USACE, Seattle District, assist in cleanup of the Makah AFS in preparation for its closure. The objectives outlined in the statement of work included pumping the contents from UST-G and removing the tank, as well as removing forty 55-gallon drums, five 30-gallon drums containing unknown products (thought to be waste oil and/or kerosene mixed with waste oil), and one 15-gallon waste oil container (USACE, 1989). Also in 1989, Shannon & Wilson, Inc., investigated soil and ground water conditions at the site for the USACE. The project scope included installing six monitoring wells; collecting subsurface soil samples; collecting two rounds of ground water samples; and collecting surface soil samples from the storage yard and a storm water drainage ditch. Pesticides and petroleum hydrocarbons were detected in soils and ground water (Shannon & Wilson, 1990). Four of the underground storage tanks were removed during the 1989 work. The three that served the gas station were found to be in excellent condition (Anderson, 1989). No leaks were detected; nonetheless, the soils underneath the tanks were sampled and analyzed for confirmation and test wells were drilled to detect ground water contamination (Anderson, 1989). The fourth tank (one of the diesel tanks that served the heating plant) was also reported to be in good condition, although earlier pressure tests had indicated it could be leaking; its piping was also reported to be in good condition (Anderson, 1989). A fifth underground storage tank was scheduled for removal and the heating plant’s fuel storage tanks were to be replaced with a single aboveground storage tank (Anderson, 1989). Heating lines were reinsulated after the removal of asbestos-containing materials (Anderson, 1989). In Shannon & Wilson’s 1990 report on the 1989 investigation, information about previous investigations was summarized from reports that have not been obtained by the Makah Environmental Restoration Team. The summary indicated that:
On behalf of the USAF, the USACE, Omaha District, contracted with Radian to produce a multi-volume management action plan for the Makah AFS to document environmental concerns and real-estate status (Radian, 1997). The plan, dated January 1997, indicated that UST-G, located southeast of Building 44, was a 600-gallon concrete underground storage tank with two 50-foot leach lines connected to it. 2002-2003 Limited Remedial Investigation
Seven ground water samples (including one field duplicate) were collected from six monitoring wells (MW-01 through MW-06). The ground water samples were analyzed for gasoline-, diesel- and lubricating oil-range hydrocarbons, BETX compounds, semivolatile organic compounds (SVOCs), and metals from the USEPA Target Analyte List. The samples from MW-02 and MW-03, which are downgradient from the general location of the burn pit, were also analyzed for PCBs and pesticides. Petroleum hydrocarbons, SVOCs, and inorganics were detected in the ground water samples. PCBs were not detected above the laboratory reporting limits in the two samples analyzed for PCBs. The concentration of diesel-range organics in the sample from MW-05 exceeded screening levels. A slight petroleum odor was noted in the purge water while this well was being sampled (Ridolfi, 2003d). Monitoring well MW-05 is downgradient from the former diesel underground storage tanks, designated UST-C and UST-D. The concentrations of gasoline-, diesel-, and lubricating oil-range organics and benzene exceeded the project screening levels in two samples collected from MW-06. Lead was also detected at concentrations above the screening levels in these samples. A petroleum odor was noted in the purge water while this well was being sampled; MW-06 is downgradient from the former gasoline underground storage tank designated UST-E (Ridolfi, 2003d). Aluminum, iron, and manganese were detected at concentrations above the USEPA secondary drinking water regulations at some of the monitoring wells. The secondary drinking water regulations are non-enforceable guidelines that regulate contaminants in drinking water that may have cosmetic effects (such as skin or tooth discoloration) or aesthetic effects (such as taste, odor, or color). Because the shallow ground water in the vicinity of the Cantonment Area is not used as a drinking water source, the cosmetic and aesthetic effects caused by these contaminants are not a primary concern (Ridolfi, 2003d). 2004 Test Pit Investigation
In December 2004, the Makah Environmental Restoration Team excavated test pits at the Cantonment Area to determine the extent to which the former pesticide rinse underground storage tank (UST-G) and the burn pit may have impacted soils, as well as to assess petroleum-contaminated soil earlier identified near the former tennis court. An additional objective was to excavate and sample test pits in the fenced storage yard to assess impacts associated with waste oil drums and transformers that were formerly stored in the yard; however, test pits were not excavated in the storage yard because abandoned vehicles and equipment blocked access to the area (Ridolfi, 2005c). Fourteen test pits were excavated using a backhoe, and ten primary soil samples (one from each of ten test pits) and one field replicate were collected from 1 to 4 feet below ground surface. Samples were not collected from TP-11-12, TP-11-13, and TP-11-14 near the tennis court, because the soil did not show visual indications of impacts. At the request of the Makah Water Department, test pits were excavated more than 10 feet away from the numerous underground utilities that run through this area. It is presumed that the impacted soil near the tennis court, which was encountered by the Makah Water Department during an earlier pipeline excavation, was limited to the area immediately adjacent to that pipeline, which is why it was not encountered in the tennis court test pits. In addition, TP-11-09 at the former burn pit was not sampled. The soil samples were analyzed for gasoline-, diesel-, and lubricating oil-range hydrocarbons, BTEX compounds, pesticides, PCBs, and metals from the USEPA Target Analyte List. In addition, five of the samples were also analyzed for SVOCs; these samples were selected for SVOC analysis based on the chromatographic profiles generated in the analysis for petroleum hydrocarbons. Low levels of pesticides, petroleum hydrocarbons, and SVOCs were detected in samples collected near the former burn pit, UST-G, and drain field, and disturbed fill and debris were observed at each test pit location. This pattern suggests that the near-surface soil was significantly disturbed during the removal of UST-G and the drain field piping or during post-removal grading. Impacted soil may have been mixed with clean soil during removal of the underground storage tank. The results also suggest that soils from the underground storage tank and drain field area may have been mixed with soils from the burn pit area. However, the concentrations of pesticides and petroleum hydrocarbons do not exceed project screening levels. SVOC results slightly exceed project screening levels in one sample from Test Pit TP-11-07. These results indicate there is no reason for further concern about these contaminants in this area. Arsenic, chromium, and iron were detected in most soil samples at concentrations above project screening levels. Many of these exceedances are less than or slightly above Puget Sound natural background concentrations in soil (Ecology, 1994) and are not believed to represent contamination associated with the site. Evidence of chlorinated pesticide degradation products, combustion PAHs, and dioxins was observed in gas chromatograph/mass spectrometer data for one or more SVOC analyses. The presence of these constituents suggests the possibility that some chlorinated dioxins/furans were produced by incomplete combustion. 2006 Ground Water SamplingDuring March 2006, the Makah Environmental Restoration Team conducted a ground water sampling event at the Cantonment Area. This sampling event was the second in a series of ground water monitoring events at the site, as planned in the SPIP (Ridolfi, 2005e); the first sampling event was conducted in 2003. These monitoring events are being conducted to evaluate contamination associated with former underground storage tanks, aboveground storage tanks, and other sources related to the Makah Air Force Station. Six ground water samples were collected from existing monitoring wells. Most of the analytical results were similar to those obtained for the 2003 samples. The organic analytical results indicate that diesel- and gasoline-range petroleum hydrocarbons are present in ground water at the Cantonment Area at concentrations greater than screening levels. The maximum concentration of diesel-range hydrocarbons was detected in a sample from MW-05, and the maximum concentration of gasoline-range hydrocarbons was detected in a sample from MW-06. As in the 2003 sampling results, some inorganic constituents, including iron and manganese, were detected at concentrations above the USEPA secondary drinking water regulations at some of the monitoring wells, but these results are not considered a primary concern (Nicholls and Hilgart, 2006d). Planned ActivitiesThe Tribe considers this site a high priority (Priority A). The following activities are planned for 2006 to 2010:
Semi-Annual Surface and Ground Water Monitoring: Ground water sampling and analysis will be conducted on a semi-annual basis using the on-site monitoring wells. If needed to monitor ground water quality, additional wells will be installed. Surface water samples will be collected from the nearby stream/drainage ditch that flows through the east end of the site to the Waatch River. Surface and ground water samples will be analyzed for contaminants of concern. Test Pit Investigation: A test pit investigation will be conducted near the former underground storage tanks and the hydraulic lift and floor drains in the motor-equipment garage to ascertain the presence of petroleum-contaminated soil. Underground Storage Tank Investigation and Removal: Underground storage tanks and associated contaminated soil will be located and removed. Test pits will be excavated to locate the tanks. If tanks are found, the removal will include identifying tank contents, emptying tanks, disconnecting pipelines, excavating and removing tanks and associated pipelines, and properly disposing of debris and tank contents. The soil around the tanks will be sampled and analyzed after tank removal to determine the nature and extent of possible contamination. Hydraulic Lift Removal: The area around the former hydraulic lift will be excavated. The lift will be dismantled and removed, and the soil around the lift will be sampled and analyzed after the removal to determine the nature and extent of possible contamination. Asbestos and Lead-Based Paint Investigation: In preparation for building deconstruction and removal, inspections will be conducted to identify possible asbestos-containing materials and lead-based paint, and sampling will be conducted. The objective is to develop an inventory of asbestos-containing materials and lead-based paint at the site, including the identification of functional spaces, material characteristics, condition, degree of damage, quantity, accessibility, and potential for disturbance. Contaminated Soil Removal: Contaminated soil will be excavated, removed, and transported off site for proper disposal. Sampling will be conducted during the excavation to determine the nature and extent of the contamination. The cleanup efforts will continue until the site meets the required cleanup standards. Voids left by the excavation will be backfilled with clean materials and compacted to the desired density to match the surrounding surface. Building Deconstruction and Removal: Abandoned buildings will be deconstructed and removed by a contractor certified to remove and handle lead-based paint. Prior to building deconstruction, asbestos-containing materials will be removed from the structures by a certified asbestos abatement contractor. The deconstruction may involve building structures, foundations, walkways, and underground and aboveground plumbing and electrical lines. The construction debris will be shipped off site for proper disposal. Additional Information:
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