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Former Discovery Chcvrolet March 28, 1995 Previous Environmental Work Based on information supplied by Ms. Nokes, we understand that the three USTs were removed in April, 1993. Four soil samples were collected from the base of the gasoline UST excavation at depths of approximately 9 to 10 feet below ground surface (bgs), one soil sample was collected from beneath the product dispenser at approximately 5.5,feet bgs, and one soil sample was collected from the base of the waste oil UST excavation at approximately 7.5 feet bgs. Groundwater was not encountered during UST removal. Information supplied by SJCEHD indicates that the product piping that ran-from the gasoline USTs to the dispenser, located inside the service bays, was left in place beneath the concrete apron outside the shop building. Petroleum hydrocarbons were detected in all soil samples collected during the UST removal. Soil samples collected from the gasoline UST excavation contained Total Petroleum Hydrocarbons as gasoline (TPHg) in concentrations ranging from 920 to 4,400 part per million (ppm). Benzene was detected in all these samples at concentration ranging from 5.9 to 39 ppm. Total lead was detected in two of these soil samples at concentrations of 19 and 4.0 ppm. TPHg was detected in the soil sample collected beneath the product dispenser at a concentration of 21 ppm. Benzene was detected in this sample at a concentration of 0.88 ppm. TPHg, Total Petroleum Hydrocarbons as Diesel (TPHd), and benzene were detected in the soil sample from the waste oil excavation at concentrations of 31, 270 and 0.18 ppm, -respectively. Lead and chromium were detected in these samples at concentrations of 7.8 and 9.2 ppm. Based on results of soil sample analyses from the UST removal, GSI performed a preliminary site assessment to further assess hydrocarbons in the soil and to evaluate if hydrocarbons had impacted groundwater beneath the site. Three groundwater monitoring wells were installed onsite at the locations shown on Figure 2 in September 1994. One soil sample from approximately 10 bgs in each soil boring was submitted for analysis. TPHg was detected in the soil sample from well boring MW-1 (340 ppm) and MW-2 (240 ppm). The benzene concentrations in these samples were 3.9 and 2.4 ppm, respectively.. Petroleum hydrocarbons were not detected in the soil sample from well boring MW-3. Groundwater in the newl install ells was measured between 9.97 and 10.49 feet bgs, and appeared 1 to flo4 north-northeast at a gradient of 0.003. TPHg was detected in the groundwater sample collected from well MW-1 (640 parts per billion, or ppb) and MW-2 (7,200 ppb). The benzene concentrations in these samples were 35 and 370 ppb, respectively. Petroleum hydrocarbons were not detected in the groundwater sample collected from well MW-3. Results of that investigation were reported in GSI Report No. 81.46701.1, Preliminary Environmental Investigation Report, dated December 7, 1994. Depth-to-groundwater and chemical analytical data are summarized in Table 1. 8146.02-1 2 f