Laserfiche WebLink
December 20, 1591 <br /> Chevron U.S.A., Inc. Pape 3 <br /> ' 02320 1883 <br /> hydrocarbons as gasoline (TPH-G) by U.S. Environmental Protection Agency (EPA)-approved methods ; <br /> 5030!8020!8015. One soil sample was analyzed for total lead by SW-846 method 6010. <br /> 4.0 SITE CONDITIONS <br /> 4.1 HVDROGEOLOGY <br /> The site is located in the northern part of the San Joaquin Valley at an elevation of <br /> approximately 25 feet. The valley fill consists of late Mesozoic through Eocene dominantly marine <br /> deposits overlain by late Tertiary and Quaternary dominantly non-marine deposits which usually contain <br /> fresh water. In Stockton area, the late Cenozoic deposits are approximately 3,000 feet thick and <br /> generally consist of alluvial gravel, sand, silt, and clay. Groundwater in these alluvial deposits is <br /> usually unconfined to semiconfined. Extensive Plio-Pleistocene lacustrine deposits, including the <br /> diatomaceous Corcoran Clay, occur in San Joaquin Valley, south of Stockton. The water beneath the <br /> clay bed is usually confined. <br /> The materials penetrated to a depth of 70 feet during drilling at the site are dominantly clays <br /> roxirr ately 30.feet.oyer a period Of three' <br /> with lenses of sand and silt The Water,tble ha �delirted app;., <br /> years fvom: ppio)<it>�at6N,:40,jaet t610406t­tieloW 9tad8.. <br /> 4.2 RESULTS OF SOIL ANALYSES <br /> Trace concentrations of petroleum hydrocarbons were detected in only one of the eleven <br /> samples submitted for analyses (Table 1, Appendix C). Sample SBI-K collected at a depth of 70 feet <br /> revealed xylene concentrations of 0.013 parts per million (ppm). Lead was not datected in sample <br /> SBI-K. The laboratory reports for the soil boring samples are enclosed in Appendix D. <br /> Results of laboratory analyses of soil samples recorded during the previous and current <br /> investigations indicate that, except for the trace levels of xylene detected in S91-K, no BTEX <br /> components have been detected in any of the soil samples collected from the soil borings drilled at the <br /> site. <br /> --j , GROUNDWATER <br /> TFfiNNOLOC1:INC. <br /> veeaMwt.rwr <br />