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Mr Michael Walton . . Walton Engineering March 20 1998 Laboratory analytical results of the soil sample composites collected from the soil stockpile indicated that elevated concentrations of TPHg and BTEX compounds and/or TPHd were detected in all four of the soil sample composites (Table 2) Total lead was detected at concentrations slightly greater than the reporting limit of the laboratory method in all four soil sample composites (Table 2) TABLE 2 LABORATORY RESULTS OF SOIL SAMPLE ANALYSES OVEREXCAVATION AND SOIL STOCKPILE 3300 WEST LANE, STOCKTON, CALIFORNIA Sample Number TPHg_ Benzene Toluene Etkiyl- Total TPHd Tatai benzene Xylenes bead Overexcavation S-19-E1n <1 0 <0 005 <0 005 <0 005 <0 010 29 na S-17-E l w <1 0 <0 005 <0 005 <0 005 <0 010 <1 0 na S-24-E i b 14 <0 005 <0 005 <0 005 0 011 230 na Soil Stockpiles SP l a-d 2 4 00087 0 290 0 130 0 950 na 21 SP l e-h 13 <0 005 0 023 00096 0 140 na 88 SP2a-d 93 00071 0 110 0 120 0 930 780 11 SP2e-h 65 <0 050 0 120 1 20 360 11,000 12 Laboratory results of sail samples are reported in milligrams/kilogram (parts per million) TPHg=Total Petroleum Hydrocarbons in the range of gasoline TPHd=Total Petroleum Hydrocarbons in the range of diesel fuel <= Less than the laboratory method reporting limit na= not analyzed DISCUSSION In November of 1997, the Regional Water Quality Control Board issued a mandate requiring that environmental samples collected from underground storage tank sites be analyzed for five prominent gasoline oxygenates and that this analytical data would be a criteria necessary for site closure The representative from SJCEHD requested, therefore, that all of the soil samples collected from beneath underground storage tanks and fuel dispenser islands at the site be analyzed for the five oxygenates These five compounds include di-isopropyl ether (dIPE), ethyl t-butyl ether(EtBE), methyl t-butyl ether (MtBE), t-amyl methyl ether(tAME), and t-butyl alcohol (tBA) A total of thirteen soil samples collected from the site were analyzed for the five oxygenates Only the soil samples collected from beneath the northern ends of the fuel dispensers contained elevated concentrations of gasoline oxygenates The soil sample collected from approximately 4 feet below ground surface at sample location FD I contained 2 5 ppm tBA and 0 11 ppm MtBE, the soil sample GRAYLAND ENVIR0N1fEVT4L Gruyland 022-160 ar 6