SITE INFORMATION AND CORRESPONDENCE

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CENTRAL VAL* REGIONAL WATER QUAY CONTROL BOARD 21 August 1991 DISCHARGER: Defense Distribution Region West, Tracy LOCATION & COUNTY: San Joaquin County CONTACT(S): Wes Harris INSPECTION DATE: 13 August 1991 INSPECTED BY: Camilla Williams ACCOMPANIED BY: Jim Pinasco (Department of Toxic Substances Control) OBSERVATIONS AND COMMENTS: The inspection was conducted at the request of Defense Distribution Region West, Tracy. During the excavation for the subsistence warehouse, old solid waste disposal sites and burn pits were discovered. The excavation is east of Building 29 and is approximately 900 feet by 400 feet by 4 feet. The footings for the foundation are about 400 feet by 10 feet by 8 feet. Tracy was using a magnetometer to identify any other potential disposal sites. Wastes appear to be confined to southern quarter of excavation, primarily in eastern portion. Waste disposal is thought to have occurred in 1940's and 1950's. This area was cropped from late 1950's to late 1960's. Employees at Tracy who have been at the site since late 1960's, indicated that waste disposal had not occurred in this area since that time. These buried solid waste disposal sites had been not identified by infrared studies. Jim and I met with Tracy personnel to observe the excavated old disposal sites and to discuss the course of action. We recommended that the potential hot spots continue to be identified with the magnetometer and staked so that as much of the excavation, as possible, could safely be released for construction. We recommended removal of the drums and potential hot spot areas and store these for sampling on non-time critical basis. We recommended that sampling concentrate on sub-soils which will be left in-place in order to determine the potential waste constituents. I recommended, and Jim agreed, that analyses include soluble Title 22 metals (with ten percent of analyses for soluble and total concentrations) , 8240's and 8270's, priority pollutants (EPA Methods 8240 and 8270) and dioxins in the burn pit areas. I did not recommend sampling of the topsoil (part of which had been stored to the south of excavation as borrow, and part had been taken off-site at the request of a land owner) . I was opposed to any sampling of topsoil because it was taken from above the waste disposal sites and because it had been cropped. I was particularly opposed to sampling for pesticides. Tracy, however, wanted to sample topsoils as a precaution. A telephone conference call between Mike Work (new EPA Project Manager) , Jim Pinasco, Wes Harris and myself was held in the afternoon (while Jim and I were still out at the site) to discuss the plan of action. EPA had Richard Brown of SAIC, EPA' s contractor, join the conversation. The following plans of actions were agreed upon by the agencies: 1. Use magnetometer to define the perimeter and potential hot spots; 2. Remove the drums; overpack and store; sample later on a non time critical basis;