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�EEflSNILI,•kE11KENNpFF, INC. The laboratory analyzing the soil samples for these constituents was Superior Analytical , Inc. , a California Department of Health Services (DOHS) certified laboratory. Included in Appendix D is Superior Analytical 's DOHS certificate, as well as the chain-of-custody forms and analytical results. Soil samples were also collected from the continuous core at soil boring SBI for sieve analysis to confirm the USCS classification. The testing method used for the sieve analysis conforms to ASTM Method D422-63(A72) . The • laboratory performing the geotechnical analysis was Harding Lawson Associates (HLA) . These geotechnical results and the samples' chain-of-custody are included in Appendix C. 3.5 SOIL SAMPLING RESULTS As previously discussed, soil samples were collected from the eight soil borings and the three monitoring well borings. These samples were analyzed for BTX&E and TPH as gasoline. Selected samples from soil boring SB6 were also analyzed for TPH as diesel . Individual certificates of analysis are included in Appendix D. Table 2 summarizes the analytical soil sampling results. Soil Borings Surroundin the Former UST Excavation. Analysis of soil samples collected from borings SB1, S85, 567, SB8, and MW3 which surround the former UST excavation contained no detectable level of TPH as gasoline at all depths analyzed. Soil samples from soil boring MW1 contained no detectable levels of TPH at all depths sampled except for a depth of 20 feet at which the TPH concentration equalled the laboratory detection limit. No detectable levels of BTX&E were found in boring SBI and S85 at all depths analyzed. Low concentration levels of one or more of the BTX&E constituents were found in boring S67 to a depth of 16.5 feet, S88 to a depth of 31 .5 feet, MWI to a depth of 21 .5 feet, and MW3 to a depth of 31.5 feet indicating that some petroleum hydrocarbon soil contamination has migrated to at least those depths at their respective locations. Analysis of soil samples from boring MW2 indicates low levels of petroleum hydrocarbon constituents above and below a depth of 16,5 feet. However, at a depth of 15.5 feet, high concentrations of toluene, ethylbenzene, xylene, and TPH as gasoline were detected. This contamination is present in a silty sand layer and indicates that the soil contamination may have migrated off-site to the north of the former excavation. Soil_ Borings Within the Former UST Excavation Analysis of soil samples collected from borings SB2, SB3, and SB4 drilled within the excavation found TPH as gasoline concentration levels ranging from non detect to 5, 100 mg/kg. SB2 contained relatively low concentrations of TPH as gasoline (7 mg/kg) at a depth of 11.5 feet and non-detect at a depth of 2I .5 feet. SB4 contained a high concentration of TPH as gasoline at a depth of 11 .5 feet (2000 mg/kg) and relatively low concentrations of TPH as gasoline (10 mg/kg or less) J 14 t