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' 20 October 200 • AGE-NC Prol ect No 95-0111 ' Page 3of8 • 26 February 1996-three soil borings (MW4,MW-5 and MW-6)were advanced at the site, ' Well borings MW4, MW-5 and MW-6 were advanced vertically to depths of 15 feet bsg, boring logs for MW-5 and MW-6 are included with Appendix B MW-4 was overdrilled and replaced due to damage incurred from the City of Tracy construction Well borings MW-4, ' MW-5 and MW-6 were converted into 2-mch diameter ground water monitoring wells with 10 feet of screen Discrete soil samples were collected at 5 feet and 15 feet bsg in well boring ' MW-5 and at 5 feet, 10 feet and 15 feet bsg in well boring MW-6 TPH-g was detected in the 5-foot soil sample collected from borings MW-5 at a concentration of 150 mg/kg TPH-d was detected in soil samples collected from MW-5 and MW-6 at concentrations ranging as high ' as 1,700 mg/kg BTEX compounds were detected in the 5-foot soil sample collected from MW-5 at concentrations ranging as high as 0 22 mg/kg,Analytical results of soil samples are summarized in Table I Field procedures and sample results were outlined in the AGE - ' prepared Quarterly Report-March 1996, dated 15 April 1996 • 19 January 1999 - two soil borings (MW-7 and MW-8) were advanced at the site to total depths of 15 feet bsg Boring logs for MW-7 and MW-8 are included with Appendix B Well ' borings MW-7 and MW-8 were converted into 2-inch diameter ground water monitoring wells with 10 feet of screen Discrete soil samples were collected at 5 feet, 10 feet and 15 feet bsg in each boring TPH-g was detected in the 10-foot soil sample collected from boring lie MW-8 at a concentration of 5 7 mg/kg TPH-d was detected in soil samples collected from MW-7 and MW-8 at concentrations ranging as high as 140 mg/kg Xylenes were detected ' in the 10-foot soil sample collected from MW-8 at a concentrations of 0 015 mg/kg Analytical results of soil samples are summarized in Table 1 Field procedures and sample results were outlined in the AGE - prepared Quarterly Report - March 1999, dated ' 10 May 1999 1 24 REGIONAL GEOLOGIC SETTING ' The property is situated within the Great Valley Geomorphic Province of California, a large, elongate, northwest trending, asymmetric structural trough The Great Valley Province has been filled with thick sequences of sediment ranging in age from Jurassic to Recent,creating a nearly flat- lying alluvial plain,extending from the Tehachapi Mountains in the south to the Klamath Mountains in the north The western and eastern boundaries of this province are comprised of the California Coast Range and the Sierra Nevada, respectively Rocks composing the basement complex of the ' province have not been completely defined but are believed to be metamorphic and igneous in origin The northern and southern portions of the Great Valley Province have been designated the Sacramento and San Joaquin Valleys, respectively ' Based on the General Soil Map from the San Joaquin County Soil Survey, published by the United . States Department of Agriculture Soil Conservation Service in 1992, the site area is within the 1 Advanced GeoEnvironmentai Inc 1