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CAMBRIA i detected in vapor samples collected during the SVE test. SVE was not recommended at the site based on the low vapor concentrations detected. SVE test results were reported in Cambria's June 22, 2001 Soil Vapor Extraction Feasibility Test Report. Groundwater Monitoring Program: There are currently three groundwater monitoring wells, three sets of paired/nested wells, and two extraction wells at the site. Groundwater samples at the site are analyzed for TPHg, BTEX, and MTBE. At Shell's request,during the second quarter 2004, groundwater samples from all wells at the site were additionally analyzed for the fuel oxygenates tertiary butyl ether, di-isopropyl ether, ethyl tertiary butyl ether, tertiary amyl methyl ether, 1,2-dichloroethane, ethylene dibromide, ethanol, and methanol. None of the additional analytes were detected in site wells. During the first quarter 2005 monitoring event, no TPHg, BTEX, or MTBE was detected in any of the sampled wells. Historical groundwater data and the first quarter 2005 groundwater elevation contour maps are included in Appendix A. SITE CONDITIONS Regional Geology: The subject site is located at the northern end of the San Joaquin Valley; a broad, flat valley filled with alluvium. The ground surface elevation of the subject site is approximately 70 feet above mean sea level (msl). In the vicinity of the site, the ground gently slopes toward the west. Soil Types: Soil types beneath the subject site are primarily fine-grained soils (silt and clay) with lesser amounts of coarse-grained sediments (sand and gravel) to the total explored depth of 76 fbg. Boring logs and cross-sectional diagrams are included in Appendix B. Hydrogeology: Groundwater occurs at approximately 27 to 35 fbg at the site. Measured depths to groundwater in the site wells have ranged historically from 24.5 to 38.9 fbg, and groundwater elevations have ranged historically from 38.8 to 26.2 feet above msl. Shallow groundwater flow beneath the subject site is variable but generally is toward the west-southwest at a gradient ranging from 0.001 to 0.04. Groundwater depth and elevation data and the most recent groundwater contour maps are included in Appendix A. 1:64 aoo5) Hydrocarbon Distribution in Soil: Up to 4,800 ppm TPHg, 68 ppm benzene, and 27 ppm MTRF. have. peen detected in soil samples collected near the southeastern dispenser, including samples collected from dispenser replacement and from boring CPT-1 and wells MW-1 and • EW-1. Subsequent soil sampling in the vicinity has shown that the hydrocarbons and MTBE 0324 5