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Chevron U S A , Inc January 7, 1992 <br /> 02320 1978 Page 2 <br /> ' Sal samples collected from the borings were analyzed by IT Corporation's Santa Clara <br /> Valley Laboratory for low boiling point hydrocarbons (total petroleum hydrocarbons-as-gasoline <br /> ' [TPN-G)), and benzene, toluene, ethylbenzene and xylene [BTEX)), high boiling point hydrocarbons <br /> (TPH-as-doesel [TPH-D)), and volatile halocarbons The only hydrocarbon component detected was <br /> ' benzene in soil samples collected from soil boring C-D at depths of 20 feet (0 12 parts per million <br /> [ppm)) and 30 feet (0 06 ppm) Analytical results were presented in WCC Environmental <br /> ' Assessment Report, dated February 13, 1989, originally issued September 2, 1988 (Appendix C) <br /> 3 2 MONITORING WELLS, AUGUST 1989 <br /> ' In a letter dated February 1, 1989, SJCPHS directed Chevron to conduct further <br /> assessment of the site Chevron contracted Dames & Moore for the additional investigation, <br /> ' including the installation of three groundwater monitoring wells <br /> July 31 through August 2, 1989, three soil borings, B-1, B-2, and B-3, were drilled to <br /> depths of 80-85 feet BGS The soils encountered in the borings are reported to be dominantly silts <br /> and clays to a depth of approximately 75 feet BGS, with fine sand and silty sand occurring from 75 <br /> feet to maximum depth of the borings at 85 feet Groundwater was encountered at a depth of <br /> approximately 71 feet BGS Groundwater monitoring wells, MW-1, MW-2, and MW-3, were <br /> ' installed in the three soil borings The water table at the site in August 1989 was found to be <br /> nearly flat, with an east-northeast gradient of less than 0 001 <br /> Twenty five soil samples and three groundwater samples were submitted to BC <br /> ' Laboratories, Inc for chemical analyses for BTEX, TPH-G, and TPH-D, selected samples were <br /> analyzed for organic lead and ethylene dibromide (EDB) <br /> In soils, the highest concentrations of hydrocarbons were found in B-2 samples collected at <br /> ' depths of 11 feet and 21 feet (up to 8,228 ppm TPH-G) and in B-1 at 16 feet (583 ppm TPH-G) <br /> TPH-G and TPH-D were not detected in soil samples from MW-1 below 16 feet, in MW-2 below 21 <br /> feet, or at any depth in MW-3, low concentrations of benzene (less than 0 28 ppm) and other <br /> ' BTEX components were detected in a few soil samples at these depth intervals No organic lead <br /> nor EDB were detected in the analyzed soil samples <br /> No dissolved hydrocarbons were detected cted in the groundwater samples collected from the <br /> three monitoring wells on August 9, 1989 Results of the soil analyses and initial round of water <br /> GROUNDWATER <br /> ' HWYBBFR RPT �� TECHNOLOGY INC <br />