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chromium(Cr), lead (Pb),Nickel (Ni), and zinc (Zn) using EPA Method 3050/6010; and <br /> the positive six ion of chromium(Cr VI) using EPA Method 7196. In addition, motor oil <br /> was quantified as part of the EPA Method 3550/8015 analytical results. The analytical <br /> results are contained in Attachment 1. <br /> Contaminants identified in the sample from below the tank invert were motor oil at <br /> 400mg/Kg, diesel at 3,300 mg/Kg, gasoline at 150 mg/Kg, and combined BTEX AT <br /> 1,167 µg/Kg (benzene was not detected at 5 µg/Kg detectoin limit) The heavy metals <br /> analyzed for were either not detected or present at background concentrations. All other <br /> constituents analyzed for were not detected. <br /> Where possible overburden soils were removed and stockpiled as clean soil. Hydrocarbon <br /> stained soils were observed starting at the surface and discontinuously extending to <br /> approximately 22 feet in depth. Because of the soil type it was difficult to segregate clean <br /> overburden soils as the excavation continued deeper, consequently a certain amount of <br /> clean soils were mixed with contaminated soils during excavation. The native soils <br /> consisted of silty sands and sandy silts of relatively high permeability to a depth of <br /> approximately 15 feet where the soil type changed to silty clays and clay silts of relatively <br /> low permeability. No non-native soils were encountered . The contaminated soils were <br /> visually and olfactorily well defined . The overall excavation measured approximately 41 <br /> feet east-west by 62 feet north-south(ignoring the excavated access ramp) and extended <br /> to a depth of 18 to 22 feet below original grade. The approximate perimeter of the <br /> excavation area is identified in Figure 3 attached. A total of approximately 2000 cubic <br /> yards of soil were excavated, 1500 cubic yards of which were contaminated. <br /> SAMPLING <br /> A total of ten samples were taken on October 20, 1994. Sample locations were as <br /> directed by Linda Turkatte of the San Joaquin County Public Health Services, <br /> Environmental Health Division(PHS/EHD) who was on site during sampling activities. <br /> Samples were collected by driving a brass sample tube into a backhoe bucket containing <br /> an undisturbed scoop of soil from the designated sample points. See Figure 3 for sample <br /> locations. Samples were stored and transported on ice. Samples were delivered to <br /> 3 <br />