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CORRAL HOLLOW SANITARY LANDFILL UNDERGROUND STORAGE TANK SITE REMEDIATION PROPOSAL The Corral Hollow Sanitary Landfill is located at 31130 S. Corral Hollow Road, approximately 5 miles southwest of the City of Tracy(Figure 1). The landfill was operated by the San Joaquin County Department of Public Works, and accepted municipal solid waste for disposal until its closure in May 1995. An equipment maintenance shed was located on the landfill site for maintaining and fueling landfill equipment. After the site's closure, the County removed the underground diesel tank used for fueling. BACKGROUND The San Joaquin County Department of Public Works removed the site's underground diesel storage tank on February 16, 1996. Soil tests taken after the tank's removal indicated diesel fuel contamination at the tank and fuel dispenser sites. A plan for determining the extent of contamination and corrective action was submitted to the San Joaquin County Environmental Health Division(LEA) on May 1, 1996. The plan was subsequently approved by the LEA, and excavation of the contaminated soil was performed on June 26, 1996. Approximately 15 and 86 cubic yards of material were removed from the dispenser and tank areas, respectively. Soil samples were taken after the areas were excavated. Locations and respective TPH diesel results of the soil samples are shown on Figure 2. The analytical data is included in this proposal as Attachment A. It is important to note that all but one of the samples were non-detect for BTEX contamination. The sample(Tank Bottom- 17') which was not non-detect was only two parts per million for toluene and xylene. Sample results indicated that all contaminated soil was removed from the dispenser area, and south portion of the tank removal area. However, some contaminated soil still remains at the tank location. PROPOSED ACTION A meeting was held between County Public Works representatives and the LEA inspector on August 7, 1996, to determine the best course of remedial action for the remaining contaminated soil. It was determined that further excavation will be performed on the north sidewall and north bottom portion of the tank area. The Department of Public Works proposes to excavate the remaining contaminated soil using a hydraulic excavator. It is estimated that approximately 100 additional cubic yards of contaminated soil will be removed. The soil will be placed on a separately lined area adjacent to the tank site along with the previously removed soil. It is estimated that approximately three to four soil samples will be taken in-place from the bottom of the excavation after the contaminated soil is removed. In addition, approximately 1-2 soil samples will be taken from the north sidewall after the excavation is complete. Soil sampling will be performed as directed by a Registered