SITE INFORMATION AND CORRESPONDENCE

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Al Jesena - 5 - 1 March 200;) Draft RI for OU#3 NCTS, Stockton (Metcalf, 1962). Moreover, chlorinated contaminants (i.e., pesticides, PCBs), as well as organic carriers/solvents used in the distribution of the products show peaks on a chromatogram that are similar to TPH-diesel. Based on communications with the San Joaquin County Agricultural Commissioner's Office, diesel oil was used as a carrier to DDT for weed control. Lightweight Superior brand oil was also used as a solvent for the DDT that came in powder form. A Senior Agricultural Biologist, who worked on the island in 1968 and then regulated the island between 1970 and 1985, stated that the Navy was known to dump crankcase oil, solvent from cleaning ships, and other waste oil/fuel in the landfill area. The biologist stated that you could smell the petroleum hydrocarbons when driving through the landfill area. According to the San Joaquin County Mosquito Abatement Agency, they performed surveillance activities on the island, as well as lab work to identify mosquitoes for the Navy. The Agency representative stated that #2 diesel oil was used as a larvacide and Weed Oil along the ditches for weed control. The RI reports WET data results depicting Total Petroleum Hydrocarbons and Total Petroleum Extractable Hydrocarbons (Table K) as Nonpetroleum Hydrocarbons, Motor Oil Range Organics, Diesel Range Organics, and Gasoline Range Organics. In order to verify this phenomenon, we request the Navy submit fingerprinting chromatograms of representative soil samples from the site and standard diesel, gasoline, and motor range chromatograms for comparison. The chromatograms must be produced at similar scales and a reasonable scale to clearly define peaks. The chromatograms must be signed by the chemist who interpreted the data. Based on our research, we believe that the petroleum hydrocarbons found in the landfill area resulted from historic weed control and pest abatement by the Navy. Therefore, the Navy should determine the extent of this contamination and propose remedial alternatives for these COCs in the feasibility study. Landfill Management Approach The Navy continues to use the term"presumptive remedy"during the SAP and RI phase of the investigation. Again, we reiterate that presumptive remedies may not meet the technologic and/or economic objectives towards cleaning up sediment, soil, surface water and groundwater at OU #3 landfill sites. As before, excavation and removal of waste, especially hazardous waste, to off-site disposal areas should be an alternative. Capping may be an alternative at sites that are above the highest groundwater level and are shown to be a threat to surface water or other environmental factors,but not necessarily for sites that are partially inundated with groundwater. Containing groundwater contaminant plumes may be an option once hot spots have been remediated using best available technology(BAT). Without knowing the content or volatility of the waste within each trench,we cannot presume to know what potential threat or nuisance the waste may pose in the future. Containers may deteriorate and leach toxic materials and/or mixed waste may physically/chemically react and potentially pose a threat to the environment. Therefore,waste characterization is critical in determining what remedial options are viable. These issues were discussed in the development of the SAP and must be resolved during the remedial investigation phase.