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APPENDIX BRISK BASED CORRECTIVE ACTION TIER 1 AND TIER 2 ANALYSIS <br /> SITE CLOSURE EVALUATION REPORT <br /> Former Beacon Station No 695 <br /> 900 South Cherokee Lane <br /> Lodi, Caltfortua <br /> Delta Project No D093-915 <br /> Page 18 <br /> California correction factor of 0 29 results in a SSTL of 6 7 mg/kg The model inputs and results are <br /> summarized in Appendix O <br /> 10.0 SUMMARUCONCLUSIONS <br /> Soil and ground water assessment and remediation at the site began in April 1985 Active remediation <br /> began in August 1989 by free product recovery in monitoring wells MW-8, MW-10 and MW-17 and <br /> continued until October 1991 Free product recovery accounted for the removal of approximately 194 <br /> gallons of petroleum hydrocarbons. Source removal continued with the installation of a SVE system in <br /> July 1991 which operated at the site for approximately 4 5 years The SVE was turned off in February <br /> 1996 due to inefficient operating conditions related to decreased influent petroleum hydrocarbon <br /> concentrations As of February 1996 the SVE system removed approximately 19,885 gallons of vapor <br /> equivalent gasoline In January 1994, tank and product line removal activities, which included <br />. overexcavation removed approximately 2,396 gallons of petroleum hydrocarbons To date, active <br /> remediation has accounted for the removal of approximately 22,475 gallons of petroleum hydrocarbons <br /> The results of remedial activities conducted at the site to date is illustrated by comparison of Du Pont's <br /> Figure 3 (Appendix A), which is an isopleth of benzene in ground water for the sampling event conducted <br /> in March 1989, with the benzene isoconcentration map (Figure 17) prepared from data collected in <br /> June 1996 <br /> A Tier 1 and Tier 2 RBCA analysis was performed for the Former Beacon Service Station No 695 The <br /> RBCA analysis indicated that the current representative BTEX distribution meets RBSLs or SSTLs <br /> established for the site Toluene, ethylbenzene, and total xylene concentrations in soil and ground water <br /> are all within the calculated RBSLs Representative benzene concentrations (95 percent UCL) in soil are <br /> below the minimum SSTL of 12 mg/kg Maximum benzene concentrations (73 Ag/L) in ground water <br /> over the last year are also below the SSTL of 580µg/L, which conservatively assumed that a residential <br /> drinking water well will be placed 254 feet from the source <br /> RPT001 915 <br />