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collected were 110 µg/l TPH-G, 1.2µg/l benzene, 1.2 µg/1 toluene and 1.0 µg/l xylenes. A 2-hour sod vapor extraction test performed on vapor extraction well VF-W-1 detected soil vapor containing TPH-G concentrations ranging from 5,500 to 6,500 mg/kg per liter of air. The groundwater flow direction in the vicinity of the Shell Service Station has been determined to be to the northeast, similar to the direction reported at the former Exxon Service Station. Though the groundwater analytical results collected from monitoring wells installed on the Shell Service Station do not indicate a substantial impact to groundwater, it is believed by Mr. Douglas Oram of EA and by Ms Elizabeth Thayer of the RWQCB that additional ' definition of groundwater impact in the vicinity of the Shell Service Station should be performed. McLaren/Hart believes that the groundwater flow direction in the vicinity of the Shell Service Station has been established to be to the northeast, away from the subject property, and is not believed to have impacted the subject site. 2.1.3 7-11 Convenience Store Three 10,000 gallon underground storage tanks are located at the 7-11 Convenience Store The tanks had failed pressure tests on May 22, 1990 and June 20, 1991, and Underground Storage Tank Unauthorized Release Reports (USTURRs) were filed following those tests Following the filing of the most recent USTURR, the regular gasoline underground storage tank was uncovered to repair the piping, soil contamination was noticed, and the piping repaired, tank covered and returned to service. There was no indication in the file at the ' PHS/EHD whether analytical tests were performed on the soil affected by the release from the tank piping. No additional information regarding soil or groundwater contamination was contained in the PHS/EHD file. ' 2.1.4 Car Wash No file exists with the PHS/EHD for the car wash located immediately to the south of the subject property According to the PHS/EHD, no fuel storage facilities are believed to be or have ever been located at the neighboring car wash. 1 3.0 FIELD INVESTIGATIONS 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, MWl through MW4 along the perimeter of the former underground storage tank farm, and MW5 at the northeast comer 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 11181ed1 5