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L _ U L Ms. Michelle Le San Joaquin County Environmental Health Department February 7,2006 Page 2 LInitial Soil Sampling and Analytical Results URS collected one soil sample from below each of the four product dispensers(designated DI-1 through DI-4) and two soil samples from beneath the product lines (designated LS-1 and LS-2). Each sample was collected by pushing a brass tube into a backhoe bucket of soil. Sample locations are shown on LFigure 2. URS collected a total of nine soil samples (designated PB-1 through PB-9) from the bottom of the tank pit. The bottoms of the tanks were approximately 13 feet below the ground surface (bgs) with an additional 2 feet of pea gravel to native soil. Each soil sample was collected at 17 feet bgs by pushing a brass tube into a fresh excavator bucket of soil collected from the locations shown on Figure 2. L Field and laboratory procedures are presented as Attachment C. i• Soil samples collected during the initial UST activities were analyzed by EPA Method 8260B for L gasoline range organics (GRO); benzene, toluene, ethylbenzene, and total xylenes (BTEX); and fuel oxygenates/additives including methyl tert-butyl ether (MtBE), tert butyl alcohol (TBA), di-isopropyl ether(DIPE), cert-amyl methyl ether(TAME),ethyl-tert butyl ether(ETBE), 1,2dibromoethane (EDB), and 1,2dichloroethane (1,2-DCA). In addition, soil samples were analyzed for total lead by EPA L Method 6010B. The analytical results are presented in Tables 1 and 2. Laboratory analytical reports and chain-of-custody documentation are presented as Attachment D. LOverall, no oxygenates/additives were detected above reporting limits in any of the soil samples collected, except for one detection of TBA in sample DI-3 (0.039 milligrams per kilogram (mg/kg]). L Benzene was not detected at or above the reporting limit in any of the soil samples collected.Lead was detected in seven of the samples at concentrations ranging from 11 to 17 mg/kg. In soil samples collected from piping areas, low concentrations of petroleum hydrocarbons were identified. The compounds and maximum concentrations detected were GRO at 1.8 mg/kg and total xylenes at 0.020 mg/kg. In soil samples collected from the UST pit, no petroleum hydrocarbons were detected above the reporting limits in any samples except for the soil sample collected in the southwest comer of the pit, PB-3, where the following compounds were reported: GRO at 2,200 mg/kg; toluene at 1.5 mg/kg; Lethylbenzene at 1.8 mg/kg;and total xylenes at 100 mg/kg. In soil samples collected from dispenser locations, elevated concentrations of petroleum hydrocarbons were identified in two of the four sampling locations: DI-1 and DI4. The highest concentrations, identified in DI4, were as follows: GRO at 1,100 mg/kg; toluene at 2.7 mg/kg; ethylbenzene at } 6.6 mg/kg; and total xylenes at 48 mg/kg. L L KAWprocessU5 BP ARCO\00595\05 UST RC vAUST Removal Rpt.doc L