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i 't 1.0- Executive Summary ` f The Toyota Town site is located at 2150 East Hammer:Lane in Stockton, California. In July, 1990 Semco removed a 2,000 gallon,gasoline underground storage tank'(UST) and a 1 ,000 gallon waste oil UST from the site. Laboratory, analyses of soil samples collected from beneath the removed tanks indicated Total Petroleum Hydrocarbons 'as gasoline (TPHg) and motor oil, plus benzene and tetracholoroethene (PCE) concentrations in excess of State and County guidelines. Therefore, additional site I characterization was warranted. In April, 1991 , AquaGeosciences, Inc. (AGI) performed a site characterization and, based upon chemical analytical results and field observations, concluded that the soil in the vicinity of the former gasoline and waste oil USTs was 'impacted. AGI recommended excavation, on-site aeration of the gasoline impacted soil, and landfill disposal of the waste oil impacted soil as the most effective means of removing the contamination at this site. In July, 1992 the San Joaquin County Public Health Services (County) approved the remedial action plan submitted by AGI. In September, 1992 a total of approximately 330 cubic yards of hydrocarbon impacted soil were excavated from the location of the former gasoline UST (East Excavation) and the former waste oil UST (West Excavation). The East and West Excavations reached a depth of 15 feet and 20 feet below surface grade (BSG), respectively. The excavated soil was segregated into "clean" and "contaminated" stockpiles. Confirmation soil samples were collected immediately after each excavation. Six (6) soil samples from the East Excavation were analyzed for TPHg and the volatile aromatic constituents (BTEX). Five (5) soil samples from the West Excavation were !analyzed for Total Oil and Grease (TOG) and Volatile Organic Halogens (VOH). Non- 'detectable concentrations of these analytes were reported in all the confirmation soil samples. In addition, analytical results of the Waste Extraction Test indicated non- detectable concentrations of soluble nickel. At the request of the County, a second round of confirmation soil samples was collected on November 23, 1992, from the West Excavation (beneath the former waste oil UST). Six (6) soil samples were collected by FGL at locations specified by Mr. Infurna of the County. All six (6) samples were analyzed for Semi-volatile Organics, TTLC Metals (Cadmium, Chromium, Nickel, Zinc, and Lead), VOH, BTEX, TPHg, Total Petroleum Hydrocarbons as diesel (TPHd), TOG, and Polychlorinated Biphenols (PCB's). Analytical results indicated non-detectable concentrations of Semi-volatile organics, VOH, BTEX, TPHg, TPHd, and PCB's; and background concentrations of the five (5) TTLC Metals. Non-detectable concentrations of TOG were also reported for five (5) of the six (6) samples, with a minimal concentration of 30 mg/kg TOG reported 2of10