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J EXECUTIVE SUMMARY This corrective action plan (CAP) serves as the framework for implementing a long-term strategy for remediation at former Chevron U S A Service Station 9-1918 Preparation of this CAP was accomplished considering all investigative and remedial data generated to date, as well as State Water Control Board Resolutions 68-16, 88-63, 92-49, and California Code of Regulations, Title 23, Chapter 16, Article 11 A review of all pertinent data was completed and summarized in a conceptual site model The model served as a basis for generating remedial objectives and associated response actions It was determined that the primary source of petroleum hydrocarbon residuals beneath the site was the former product storage and distribution facilities The secondary source of petroleum hydrocarbon residuals was identified as soil and groundwater impacted with weathered gaso- line The compounds of concern that distinguish the residual plume are the constituents of • gasoline, including benzene, toluene, ethylbenzene, and xylenes Subsequent to preparing the site conceptual model, site-specific environmental, public health, and safety goals were developed Site water quality (environmental) goals were identified for an area within a proposed compliance boundary, and at the proposed compliance boundary Within the proposed compliance boundary, water quality goals linked with using groundwater as a municipal supply were specified Background residual concentrations were specified as water quality goals at the proposed compliance boundary The site public health and safety goal was specified to eliminate the potential for exposure to, or use of impacted groundwater Predicated on the need to achieve the site-specific environmental, public health, and safety goals, groundwater and soil-based remedial objectives were established Appropriate response actions were identified and associated technologies were combined into remedial alternatives Two alternatives were evaluated (1) Soil Excavation and Off-site Disposal (Alternative 1), and (2) Soil Vapor Extraction/Bioventing (Alternative 2) Each alternative considered includes common components associated with addressing groundwater impact Technical, institutional, environmental safety, and economic criteria were used to evaluate the alternatives It was determined that Alternative 2 was the most feasible for long-term applica- tion Elements of Alternative 2 are • remedial investigation(plume delineation and off-site source search), 3201337B/1918REV ii August 31, 1995 i