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1 s <br /> Ms. Carol Oz Project 791700 <br /> August 12, 1999 <br /> Page 7 <br /> samples collected from stockpiles SP-1 were submitted to a state-certified analytical <br /> laboratory and analyzed for TPHG, BTEX, MTBE, oxygenates, and total lead. The <br /> samples collected from SP-1 were composited four to one by quadrant. <br /> Analytical results of the four 4-point and one 3-point composite samples collected from <br /> stockpile SP-1 contained concentrations of TPHG ranging from 14 to 380 mg/kg. <br /> Benzene appeared in one stockpile sample at a concentration of 0.48 mg/kg. MTBE (using <br /> USEPA Method 8260) was detected in all stockpile samples at concentrations ranging <br /> from 0.424 to 1..16 mg/kg. In addition, all other oxygenates were below laboratory <br /> detection reporting limits. <br /> Stockpile soil sample analytical results are presented on Table 1. The Appendix B <br /> contains copies of Certified Analytical Reports and chain of custody documents. <br /> After receiving stockpile analytical data, stockpile SP-1 was subsequently removed from <br /> the site by Dillard Trucking, Inc. Dillard Trucking, Inc. transported of the stockpile at <br /> BFI Landfill, Vasco Road, Livermore, California. The soil stockpile disposal manifest is <br /> included in Appendix D. <br /> NEW UST INSTALLATION AND EXCAVATION BACKFILL PROCEDURES <br /> Henderson Construction replaced the original two 10,000-gallon and one-8,000 with two <br /> 20,000-gallon USTs. With the new USTs in place, the excavation was backfilled with pea <br /> gravel on June 21 through 23, 1999. The UST complex was backfilled to within <br /> approximately 1 foot of surface grade. Henderson placed the backfill in accordance with <br /> the contract specifications. <br /> A/B was imported and placed for the asphalt base. After backfilling activities concluded, <br /> Henderson paved the area with asphalt. <br /> CONCLUSIONS <br /> The petroleum hydrocarbon impacts were identified in the northern and southwestern parts <br /> of the former gasoline UST complex at depths of 17 to 18 feet bgs. Former UST complex <br /> soil samples indicate the impacts are distributed in the northern and southwestern part of <br /> the former gasoline UST complex (17-1-S, T-1-N, T-2-N, and T-3-N). Detcctcd TPHG <br /> concentrations range from 240 to 11,000 mg/kg. Soil samples collected from the central- <br /> southern and southeastern corner of the former UST complex did not contain TPHG at <br /> concentrations exceeding method reporting limits (T-2-S, and T-3-S). Sidewall samples <br /> CP\E:lARCO\21861REPORTS12186P105.DOC-95 Isg:l �istsutC�e <br />