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1 .0 INTRODUCTION/PREVIOUS WORK <br /> ` This report is being submitted in response to a directive <br /> issued by the San Joaquin Local Health District (SJLHD) for <br /> a subsurface investigation at the subject property (Figure <br /> 1 ) . The property is currently vacant; it was formerly <br /> occupied by De Rollo Mazda, a car dealership. <br /> On April 21, 1987 a 1000 gallon underground (u/g) gasoline <br /> r, storage tank was removed from the subject property (Figure <br /> 2 ) . Holes were noted in the tank during the removal <br /> inspection. A soil sample was recovered from beneath the <br /> ` tank at a depth of 14 feet below grade. The laboratory <br /> results for the sample recorded benzene, toluene, xylenes <br /> and total petroleum hydrocarbon (BTX/TPH) concentrations of <br /> 120, 470, 870 and 2400 parts per million (ppm) , respectively <br /> (Table 1 ) . <br /> On October 19, 1988, a 5000 gallon u/g gasoline tank and a <br /> 300 gallon u/g waste oil tank were removed from the project <br /> site (Figure 2) . Soil samples were collected from each end <br /> of the gasoline tank pit at a depth of approximately 15 feet <br /> below grade . The samples were analyzed for benzene, <br /> toluene, xylenes, ethylbenzene (BTX & E) ; total petroleum <br /> hydrocarbons as gasoline (TPH) ; ethylene dibromide (EDB) and <br /> total lead ( Pb ) . Laboratory results for the samples <br /> indicated concentrations of TPH and Pb above State <br /> designated levels (Marshack, 1986 ) in the north end of the <br /> former tank pit. The laboratory results are summarized in <br /> ` Table 1 . <br /> A soil sample was also recovered from beneath the waste oil <br /> tank at a depth of approximately 6 feet below grade. The <br /> 6. sample was analyzed for BTX & E, TPH, chlorinated <br /> hydrocarbons, metals and PCB' s. Laboratory results for <br /> these constituents recorded concentrations less than method <br /> L detection limits for all constituents except chloroform (7 <br /> ppb ) and trichloroethane ( 30 ppb ) ( Table 2 ) . These <br /> concentrations are significantly below the State designated <br /> ` levels to protect groundwater at a hypothetical average <br /> site . A May 10, 1989 correspondence from the SJLHD <br /> indicated assessment of trichloroethane and chloroform must <br /> be indicated in the workplan. <br /> 2.0 TECHNICAL DATA <br /> 2. 1 Name and address of site, tank owner and contact person: <br /> Site and Tank Owner: De Rollo Mazda <br /> ` 308 North Grant <br /> Stockton, CA 95202 <br /> 1 <br />