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Mr.Charles Carmel Page 2 of 2 <br /> July 1, 1993 <br /> *4., The contents of the remaining liners from each California Sampler and the auger cuttings were <br /> examined by the field geologist. Soils from the samplers were described using the Unified Soil <br /> Classification System. The field geologist also noted moisture content and any evidence of <br /> petroleum hydrocarbons (i.e. soil staining and odor). Geologic logs for each borehole were <br /> prepared under the direction of a California Registered Geologist and are included in the <br /> Attachments. <br /> Selected soil samples from each borehole were analyzed by Sequoia Analytical, a California <br /> Department of Health Services (DHS) certified laboratory, for total purgeable petroleum <br /> hydrocarbons (TPH-G) by U.S. Environmental Protection Agency (USEPA) Method 8015 and <br /> benzene, toluene, ethylbenzene, and xylenes (BTEX) by USEPA Method 8020. Results of the <br /> laboratory analyses are summarized on Table 1. Laboratory analytical reports and <br /> Chain-of-Custody forms are included in the Attachments. <br /> The boreholes were backfilled with cement-bentonite grout to grade. <br /> Summary of Results <br /> Soil encountered in the boreholes drilled during this investigation consisted of silt and sandy silt <br /> with interbedded sand layers. Ground water was encountered at a depth of about 12 ft. bgs. <br /> Laboratory analysis of the soil samples showed that petroleum hydrocarbons were present in all <br /> of the boreholes. Concentrations of TPH-G in soil ranged from not detected to 720 mg/kg. The <br /> highest concentration of TPH-G was found in boreholes Bl and B2. In general, the <br /> concentrations of petroleum hydrocarbons increased with depth in each borehole. <br /> Based on these results, it is our understanding that ARCO plans to install the new USTs into the <br /> same area of the Site as the existing USTs. The new USTs will not be installed north of the <br /> pump islands where soil borings B1 through B5 were drilled. <br /> Respectfully submitted, <br /> ROUX ASSOCIATES <br /> Paul Sup ke Todd Ramsden, R.G. <br /> Senior Hydrogeologist California Registered Geologist No. 5687 <br /> TR:ch <br /> Attachments: <br /> Figure 1 Site Location <br /> Figure 2 Site Plan <br /> Table 1 Summary of Soil Sample Analyses <br /> Soil Boring Logs <br /> Laboratory Reports <br /> Chain-of-Custody Documentation <br /> FVXncASSOCIATES <br /> Doc ##A159WO1.1.6 <br />