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1 � s May 4, 1993 Project No. EK-6032-2 ' Document No. 9305-4002.RPT ' Two of the borings were located on the northeast and southeast sides of the 10,000 gallon underground diesel fuel tank at Thorsen Trucking, Inc. The southeast boring extended to an ' approximate depth of 21.5 feet, and the northeast boring, on the assumed down gradient side of the tank, extend to 36.5 feet with groundwater encountered at a depth of 34.5 feet. Soil samples ' were collected from the borings at approximate depth intervals of 5 feet and one reconnaissance groundwater sample was collected with a Hydropunch. ' Two additional exploratory borings were drilled near the northern boundary of the site, adjacent to the former Bloom Auto Wrecking yard. One of these borings was drilled to a depth of 11.5 feet ' and the other to 36.5 feet with groundwater encountered at 34.4 feet. 'Soil samples were collected from the borings at approximately 5 foot intervals. A Hydropunch groundwater sample was ' collected from the deeper boring. ' Finally, three exploratory borings were drilled along the southern site boundary, adjacent to Quintero's Auto Dismantling. The borings located on the eastern and western half of the property boundary were advanced to a depth of 11.5 feet and the center boring extended to 36.5 feet with ' groundwater encountered at 30.5 feet and then at 29 feet after approximately one hour. Soil samples were collected at approximate depth intervals.of 5 feet during the drilling of the borings ' and one Hydropunch groundwater sample was taken from the deep boring. ' The drilling was performed on April 23, 1993 using a MobileTm B53 truck mounted drill rig equipped with an 8-inch diameter hollow-stem auger. ' Relatively undisturbed soil samples were collected at 5 foot minimum depth intervals and at major lithologic changes using a California split spoon sampler with internal brass Iiners. As each boring ' was advanced to the desired sampling depth, the sampler was lowered to the bottom of the hole and driven 18 inches ahead of the auger with a 140-pound hammer dropping 30 inches in ' accordance with ASTM D 1586. The auger and other tools used in the holes were steamed cleaned before use and between borings to minimize the possibility of cross-contamination. The lowermost sleeve at each sample interval was screened for total organic vapors with aphoto- ionization detector (PID). The PID utilized an 11.7 eV lamp and was calibrated with a standard of isobutylene gas at a concentration of 100 parts per million. Headspace vapor analysis was performed by first discarding a portion of the soil retained at one end of the sleeve to produce a 1 3 1