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a <br /> Soil Contamination Removal <br /> Minor oil and grease contamination remains in the subsurface soil at the Stan Morri Ford <br /> Dealership in Tracy, California as a result of spills from an underground waste oil tank. <br /> Minor soil contamination was still present in !he south wall of the former tank excavation <br /> following removal activities in January 1990. The contamination extends toward the Ford <br /> Service Garage, but appears to be restricted to a zone approximately 3 feet long by 3 feet <br /> deep,at a depth of 5 to 8 feet below the surface. The width of this zone of contamination <br /> was defined by a single soil boring(SB-1) drilled by Osterberg and Stewart in June 1990 as <br /> a part of the Problem Assessment investigation. The boring was drilled halfway between the <br /> former tank excavation and the Ford Service Garage. Although the soil boring contained <br /> non-detectable levels of BTXE and diesel,slight discoloration in the soil at a depth of 6 to <br /> 7 feet indicated that the contamination was located between the boring and the former south <br /> wall of the excavation. <br /> Murray&Associates proposes to use a hydrodigger to excavate the remaining contaminated <br /> soil. The soil excavated will be divided into clean and contaminateed piles and placed on <br /> plastic sheeting. The contaminated soil will be sampled, analyzed for total petroleum <br /> hydrocarbons (TPH) and oil and grease and placed into 55 gaIIon drums. If the analysis <br /> indicates a TPH concentration greater than 100 ppm, the soil will be classified as a <br /> California Regulated waste and manifested for off-site disposal at a Class II facility. If <br /> concentrations are below 100 ppm TPH, the material may be able to be transported to a <br /> i <br /> Class III landfill for disposal. <br /> Two confirmation soil samples will be collected from the side walls of the excavation to <br /> ensure that all contaminated soil has been removed. Both of these samples will also be <br /> evaluated for TPH and oil and grease. Each soil sample will be placed into a clean wide- <br /> mouth glassjar,-capped.with.a_teflon-lined-lid,--labeled,-placed-on ice-and-transported-to <br /> California Water Laboratory under Chain of Custody within 24 hours of collection. <br /> Following the excavation of soil the area will be backfi!Ied with clean sand and compacted <br /> to at least SO percent ,)f maximum density. <br /> 2 <br />