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24 July 1991 <br /> (GeoAudit CV 45-49C5. 1-10) <br /> Page 2 of 7 <br /> SOIL EXCAVATION WORKPLAN <br /> Western Lift, Inc. <br /> SITE DESCRIPTION <br /> The site is located in a flat industrial area south of Stockton <br /> (Figure 1 - Location Map, 7 . 5 Minute Stockton West Quadrangle, USGS <br /> Topographic Map Series, 1976) . The facility consists of a large <br /> warehouse and adjoining office and exterior fenced parking/delivery <br /> areas. <br /> The site is underlain by unconsolidated Quaternary alluvial <br /> sediment. Groundwater is estimated at 25-30 ft below surface grade <br /> (personal communication from Dennis Corcoran, San Joaquin County <br /> Department of Public Works, Flood Control Section, 1991) . <br /> PREVIOUS WORK <br /> Three underground tanks were removed from the delivery area by <br /> Frahm Construction on June 6, 1991. Two soil samples were collected <br /> from below each tank and one sample was collected from the <br /> northwest wall of the excavation (Figure 2 - Site Plan) . No <br /> contamination was detected beneath the diesel tank, and only minor <br /> contamination (13.8 ppm TPH and 6-8 ppm total lead) was found <br /> beneath the leaded gasoline tank in the center of the excavation <br /> and in the sidewall (6 ppm total lead) (Table 1) . Sample 6, from <br /> beneath the south end of the leaded regular gasoline tank on the <br /> western side of the excavation, contained trace amounts of BTE&X <br /> compounds and total lead of 4 ppm, but the sample from beneath the <br /> north end was contaminated with 1717 ppm TPH-g, 30 ppm total lead, <br /> and moderate concentrations of toluene, ethylbenzene, and xylene <br /> (Table 1) . Visual examination also suggests that contamination is <br /> present in the northwest sidewall near the former fuel dispenser <br /> down to a depth of 3-4 feet. <br /> The excavation is approximately 20 ft long x 14 ft wide x 8 ft <br /> deep, with a 9 ft x 3 .5 ft extension beneath the former dispenser <br /> island. Approximately 85 cu. yds. of soil were removed during the <br /> excavation and are presently stockpiled in two piles adjacent to <br /> the tank cavity. <br /> PROPOSED EXCAVATION AND SAMPLING <br /> Because total lead concentrations in several samples exceed the 5. 0 <br /> . ppm hazardous waste limit, we propose to excavate the contaminated <br /> soil beneath the dispenser island and the regular gasoline tank and <br /> transport it to a Class I landfill. Confirmatory soil samples will <br /> be obtained from the overexcavation to demonstrate that the <br /> 2 <br />