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.or s Ms. Letitia Briggs Project 20805-224.002 March 24, 1999 Page 2 (TPHG) and benzene, toluene, ethylbenzene, total xylenes (BTEX) using DHS LUFT, and for oxygenates (methyl tert-butyl ether, tent-butyl alcohol, di-isopropyl ether, ethyl tert-butyl ether, and tent-amyl methyl ether) using USEPA Method 8260. In addition, soil samples PL-7 (4.3') and PL-11 (4')were also analyzed for total lead using USEPA Method 6010A. Based on soil sample field screening results (using the FID), limited overexcavation in the vicinity of sample locations PL-7, PL-8, and PL-11 was performed on February 17, 1999. Overexcavation was performed by ARCO's contractor under the direction of a Pinnacle geologist. Ron Rowe of SJCPHS was on-site to observe the activities. A backhoe was used to excavate soil at locations PL-7 and PLr8 to a depth of 4.5 feet. Approximately 4 cubic yards of soil were removed during the overexcavation activities. Soil samples PL-7 (5') and PL-8 (5') were collected beneath the original sample locations and sample PL-8SW (3.5') was collected from the southwest sidewall adjacent to former dispenser and product line sample location PL-8. Limited overexcavation was performed near sample location PL-11 using hand tools. Due to existing electrical lines and vapor recovery Iines, and native hardpan soils (encountered at approximately 3 feet bgs) only the overlying pea gravel was removed. Samples PL-7 (5'), PL-8 (5'), and PL-8SW (3.5') were submitted to Sequoia Analytical and analyzed for the above listed parameters. Approximately 60 cubic yards of soil were excavated and stockpiled on-site and covered with visqueen. Pinnacle collected a four-point stockpile sample on February 17, 1999. Sample SP-1 was submitted to Sequoia Analytical were it was composited and analyzed for TPHG, BTEX, and total lead using the above listed methods. On March 5, 1999, soil stockpile SP-1 was transported off-site by Dillard Environmental Services and disposed of at BFI Landfill in Livermore, California. Stockpile disposal documentation is included as Appendix A. ANALYTICAL RESULTS Results of verification soil sample analysis, overexcavation sample analysis, and stockpile characterization are presented in the following sections. Verification Soil Sample Results TPHG was detected in six of the 16 soil samples at concentrations ranging from 1.03 milligrams per kilogram (mg/kg) in PL-9 (4') to 7.32 mg/kg in PL-4 (3.3'). Benzene was detected in sample PL-7 (4.3') at a concentration of 0.187 mg/kg. MTBE was detected in seven of the 16 samples at concentrations ranging from 0.186 mg/kg in PL-5 (4') to 5.16 mg/kg in PL-10 (4.3'). Tert-butyl alcohol was detected in sample PL-10 (4.3') at a concentration of 44.0 mg/kg. Total lead was below the elevated laboratory detection limit for samples PL-7 (4.3') and PL-11 (4'). Table 1 CPIE:WRCO154691REPORT515469P102.DOC-9511sg:I Auu�