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i NOW Ms. Carol Oz Project 791700 August 12, 1999 Page 6 0.545 mg/kg. MTBE was detected in all four sidewall samples with concentrations ranging from 0.221 to 23.8 mg/kg. Other oxygenates did not exceed laboratory method reporting limits. See Table 1 for analytical results and Appendix C for copies of certified analytical reports. Piping Excavation and Dispenser Soil Samples Soil samples PL-1 through PL-5 and PL-7 through PL-12 did not contain TPHG or benzene. TPHG was detected at 7,040 mg/kg in soil sample PL-6, collected from the piping trenches at 5 feet bgs. Limited overexcavation was conducted at piping line sample PL-6 (5 feet bgs). The sample collected at 7 feet bgs contained TPHG at a concentration of 3,020 mg/kg. The detected benzene concentrations in sample PL-6 (5 feet) and PL-6 (7 feet) were 5.06 mg/kg and 0.634 mg/kg, respectively. MTBE was detected in five soil samples with concentrations ranging from 0.114 to 19.6 mg/kg. The MTBE concentrations at PL-6 (5 feet) was 88.9 mg/kg and the concentrations decreased to 11.9 mg/kg in the sample collected at 7 feet bgs. Five soil samples were collected along the vapor recovery line excavation. All five vapor recovery line soil samples were below laboratory detection limits for petroleum hydrocarbon constituents. Seven dispenser samples did not contain TPHG and benzene was not detected in any of the eight samples. Dispenser island soil sample D-2 contained TPHG at a concentration of 1.2 mg/kg and MTBE was below laboratory detection limits. An additional sample was taken from between the locations of samples D-7 and D-8 (D-7/8) at 7 feet bgs due to high PID readings. Analytical results of dispenser soil samples D-3 and D-4 indicated low concentrations of BTEX constituents. Soil sample D-3 contained concentrations of toluene and total xylenes detected at concentrations of 0.0155 and 0.0247 mg/kg respectively. Soil sample D-4 contained total xylenes at a concentration of 0.00874 mg/kg. Oxygenates analyzed using USEPA Method 8260 detected MTBE in three samples, ranging from 0.0629 to 41.7 mg/kg. Total lead was present in product piping line soil sample PL-6 (5') at a concentration of 25.6 mg/kg. In all other dispenser soil samples, oxygenates were below laboratory detection limits. See Table 1 for analytical results and Appendix B for copies of certified analytical reports. Soil Stockpiles Soil stockpile SP-1 contained approximately 1,000 cubic yards of soil generated from the UST excavation and associated product line and dispenser trenching. Soil stockpile CP1E:1ARCO\21861REPOR i'S12186P105.DOC-95 Isg:l ;V4W4&