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Mr. Lloyd Gums A91701.01 C September 20, 1996 Page 6 Soil sample analytical results are summarized in Table 2. Laboratory reports of analyses and chain-of-custody documentation are attached. so pca elts Number T HA-8A 6-6.5 ND ND ND ND ND ND ND HA-10A 73-8 ND ND ND ND ND ND ND Detection Limit for 0.005 0.005 0.005 0.005 0.025 1.010 Reporting Purposes MTBE = methyl tert-butyl ether TPH-G = total petroleum hydrocarbons-gasoline range constituents TPH-D = total petroleum hydrocarbons-diesel range constituents FBSG = feet below site grade(approximate) NA = not analyzed CONCLUSIONS Based on the assumptions and calculation described above, our estimate of the mass and volume of residual diesel PPCs remaining in the soil beneath the northwestern fuel dispenser island is 1,365 pounds, or 196 gallons. Our estimate of the mass and volume of residual gasoline PPCs remaining in the soil beneath the northwestern fuel dispenser island is 85 pounds, or 14 gallons. The above masses and volumes are based on analytical testing methods that detect and measure total petroleum hydrocarbons within specific carbon chain ranges. Since the carbon chain ranges of diesel and gasoline overlap, the analyses performed for this investigation could not differentiate between quantities of diesel and gasoline in a single sample. Some of the diesel quantified on the laboratory report forms is gasoline, and some of the gasoline quantified is diesel. Since our method of estimating diesel and gasoline volumes and masses did not account for the aforementioned overlap of carbon chain ranges, the total masses and volumes provided in this report are considered conservative. The laboratory analytical results for soil samples collected from the area of the southeastern fuel dispenser island during the piping removal action in April, 1994, during the soil sampling in December, 1995, and during the soil sampling on July 12, 1996 did not detect the presence of PPCs in the soil samples. These findings suggest that PPCs are not present in the soil adjacent to the southeastern dispenser island.