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APPENDIX BMISK BASED CORRECnVE 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, California <br /> Delta Project No D093-915 <br /> Page 13 <br /> 7 1.3 Ensure Point Evaluation of Chemicals of Concern <br /> Soil and ground water have been impacted by the COCl, but are confined within site boundaries and have <br /> not impacted a source of drinking water. On-site structures have not been reported to exhibit vapors <br /> which would indicate impact by a petroleum release <br /> 8.0 TIER 1 EVALUATION <br /> S.1-Exposure Pathways <br /> Several exposure pathways were considered for the Tier 1 evaluation and a summary of the evaluation <br /> is presented m Table 14. The ASTM-reviewed Tier 2 RBCA Guidance Manual for Risk-Based <br /> Corrective Action and associated spreadsheet models were used m the Tier 1 evaluation(Conner, et al , <br /> 1995) Appendix K provides a summary of the Tier 1 inputs into the model including default parameters <br /> and exposure pathways considered. <br /> 8.2 Exposure to Ilmpacted Subsurface and Surface Soils <br /> 8 2 1 Vapor Inhalation and Dust ingestion <br /> The site is primarily paved and will likely remain paved in the future Due to site paving the emissions <br /> of vapors and/or fugitive dust would be lmuted and this pathway was not evaluated further <br /> 8 2 2 Dermal Contact <br /> Due to limited soil impact within 24 feet of the surface, it is not expected that any future construction <br /> activities will expose individuals to petroleum hydrocarbons The site was recently refurbished and is <br /> now a Texaco station This pathway was not evaluated further <br /> 8 2 3 Vapors_to Enclosed Spaces <br /> Two buildings are on-site and it is anticipated that a building will exist on-site in the future The Tier <br /> 1 Guidance system model was used to estimate RBSLs and is described in Appendix L The model <br /> estimated a RBSL of 0 023 mg/kg for benzene which becomes 0 007 mg/kg when multiplied by the <br /> California Correction Factor for benzene 0 29 The results of the modeling are summarized in Table 11 <br /> RPT001 915 <br />