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' not conducted due to permitting issues TPH-g was detected in the 25-foot soil sample from • MW-6 and the 50-foot soil sample from MW-7 at concentrations of 3 0 mg/kg and 12 mg/kg, ' respectively, MTBE was detected from MW-7 at depths between 50 feet and 90 feet bsg at concentrations as high as 28 mg/kg,respectively,TAME was detected in the 50-foot and 70- foot soil samples from MW-7 at concentrations of 0 11 mg/kg and 0 011 mg/kg,respectively, TBA was detected from MW-7 in the 50-foot soil sample at a concentration of 2 9 mg kg Laboratory analysis of initial water samples collected from MW-7 detected MTBE at a concentration of 16µg/l A report of findings(Quarterly Report- Third Quarter 2003, dated ' 02 February 2004) was submitted by AGE to the SJCEHD ' Between November 1999 and September 2003, fourteen ground water monitoring events were performed at the site to monitor dissolved petroleum hydrocarbon concentrations in ground water and to characterize ground water flow direction and gradient on the site Generally, TPH-g was ' detected in water samples collected from wells MW-1,MW-2 and MW-3 at concentrations as high as 23,000 gg/l, BTEX compounds from wells MW-1 through MW-3 at concentrations as high as 1,700 µg/1, and MTBE from wells MW-1, MW-2, MW-3 and MW-7 at concentrations as high as ' 19,000 µg/1 , Based on the curent area bound by wells MW-1 through MW-7, the lateral extent of the dissolved ' petroleum hydrocarbon plume is not known toward the south The vertical extent is marginally defined beneath the UST tank pit area (MW-7) and approximately 85 feet south(downgradient) of the former UST tank pit area(CPT-1) 5.0. REGIONAL GEOLOGIC SETTING According to a Geologic Map of California, published in 1966 by the California Department of ' Conservation Division of Mines and Geology,the site area is within the Great Valley Geomorphic Province(GVGP)of California, a large, elongate,northwest trending structural trough The GVGP is subdivided into two mayor divisions designated the Sacramento and San Joaquin Valleys, which ' have been filled to the present elevation with thick sequences of sediment ranging in age from Jurassic to present day, 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 Mountains, respectively ' Based on a 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 described as being within the Tokay-Acampo(TA) association The TA soils are-located within low fan terraces ' along the Mokelumne River, and generally consist of moderate well drained, moderate coarse textured soils that are deep to a cemented hardpan The TA soils generally formed in alluvium derived from granitic rock sources Advanced GeoEnviron mental,Inc 1