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McLaren/Hart Soil Sampling and monitor well construction were conducted at the subject site on November 3 through November 5, 1992 A total of five monitor wells were installed, MW1 through MW4 along the perimeter of the former underground storage tank farm, and MW5 at the northeast corner of the subject site in the inferred downgradient direction Soil borings were drilled to a maximum depth of 45 feet below ground surface, and monitor wells were installed within the boreholes to a maximum depth of 40 feet below ground surface The analytical results of the soil samples collected during monitor well drilling indicates that concentrations of TPH as gasoline (TPH-G) were detected in the soil collected from monitor wells MW2 through MW5 BTEX compounds were detected in the soil samples collected from monitor wells MW2, MW3 and MW4 The maximum concentrations of TPH-G detected in soil samples were from the samples collected at 25 feet below ground surface, at the historical highest seasonal groundwater elevation The maximum concentrations ranged from 12 ppm to 420 ppm TPH-G Groundwater samples were collected from the five monitoring wells on November 19, 1992 June 4, 1993 and September 3, 1993 and submitted for laboratory analysis The analytical results are shown on the attached table In June 1993, McLaren/Hart removed a total of 360 cubic yards of soil material stockpiled on black plastic within the excavation and transported the soil off-site for disposal at Forward Class III Landfill in Stockton, California The excavation was backfilled and resurfaced to restore the property to a functional condition SCOPE OF WORK FOR SOIL CHARACTERIZATION AND REMEDIATION The scope of work will include the following Delineation of the petroleum hydrocarbon plume in the soil Based on the data collected during the additional soil characterization activities, and the data presented in the TMC, Treatek and McLaren/Hart reports, a feasibility study will be written and submitted to PHS/EHD Performance of a soil vapor extraction pilot test to assess whether the soil vapor extraction methods can achieve the necessary clean-up goals Meetings with PHS/EHD to select a remedial option and clean up goals The subject site appears to be well suited for the successful application of a soil vapor extraction (SVE) system relative to other remedial options based on 1) the high volatility of the contaminant (gasoline), 2) the depth of the contaminated soil material (approximately 25 to 30 feet below grade) and 3) the high air flow rates of the soil matrix within the contaminated zone, which McLaren/Hart assumes will be adequate for vapor removal McLaren/Hart is confident Q9291ed2 2