SITE INFORMATION AND CORRESPONDENCE

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•W •.r Site Background Information: California Stop Page 3 of 7 island to a depth of approximately 2 feet bsg, where native soil was encountered. Under direction of EHD representatives, one soil sample was collected beneath each offourdispensers by Parker Environmental Services of Pittsburg, California and submitted for laboratory analysis. Soil samples were collected at depths between 0.5 feet and 2.5 feet bsg. TPH-g were reported in each soil sample at concentrations ranging from 770 mg/kg to 10,000 mg/kg. Benzene, toluene, ethylbenzene, and total xylenes(BTEX)were reported in each sample at concentrations ranging from 0.64 mg/kg toluene to 1,300 mg/kg xylenes. MTBE was reported in three of four soil samples at concentrations as high as 340 mg/kg. Tertiary-amyl methyl ether(TAME)was reported in two of four samples at concentrations as high as 15 mg/kg. Di-isopropyl ether (DIPE), ethyl tertiary-butyl ether (ETBE), and tertiary-butyl alcohol (TBA) were not reported in any of the four samples collected and analyzed, however, detection limits for all samples were raised due to matrix interference. August 2005 A total of six soil probe borings (131 through 136) were advanced at the site to depths of approximately 25 feet bsg for collected for soil and grab groundwater samples. TPH-g were reported in soil samples collected from borings 131 through B3 at concentrations as high as 29 mg/kg. MTBE was reported in all soil samples, except 135-20 and 136-25, at concentrations as high as 25 mg/kg. TAME was reported samples 131-15, 131-25, 132-15, and 133-15 at concentrations as high as 0.038 mg/kg. Xylenes were reported in soil sample 132-25 at a concentration of 0.022 mg/kg. TPH-g were reported in groundwater samples B1 through B3 at concentrations as high as 86,000 micrograms per liter(pg/l; 132). MTBE was reported in samples B1 through B3 and B6 at concentrations ranging from 75 lag/I to 55,000 pg/I. TAME was reported in samples B1 through B3 at concentrations as high as 120 pg/I. BTEX constituents were reported in samples B2 and B3 at maximum concentrations in sample B3 of 110 lag/I of benzene, 390 lag/I of toluene, 270 lag/I of ethylbenzene and 680 lag/I of xylenes. 01 August Monitoring well pilot borings MW1, MW2, and MW3 were drilled to a 2006 total depth of 30 feet bsg and were completed as 2" groundwater monitoring wells, screened from 10 feet to 30 feet bsg. TPH-g were reported in soil samples MW1-20 and MW3-30 at concentrations of 1.5 mg/kg and 3.2 mg/kg, respectively. MTBE was reported in samples MW1-15, MW1-20, MW1-30, MW3-15, and MW3-30 at concentrations Advanced CeoEnvironmentoI,Inc.