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I H • • 02 May 2001 AGE-NC Project No 97-0301 Page 3 of 7 at the site as part of site assessment activities TPH-g, TPH-d and TPH-k were detected in soil samples collected from MW-5 and MW-7 at concentrations as high as 7 6 mg/kg,BTEX compounds were detected in soil samples from MW-5 and MW-7 at concentrations as high as 1 1 mg/kg, 1,2-DCA was detected in a soil sample from MW-7 at a concentration of 75 mg/kg TPH-g, TPH-d and TPH-k were detected in water samples collected from wells MW-1 through MW-7 at concentrations as high as 67,000 µg11 and BTEX compounds detected as high as 14,000 µg/l, MTBE was detected in the water sample collected from MW-I at a concentration of 7 6 Mg/l, 1,2-DCA was detected in samples collected from wells MW-1,MW-5 and MW-7 at concentrations as high as 1,200µg11 Analytical results of soil and ground water samples collected during the December 2000 investigation are summarized in Tables 2 and 3, respectively Based on the ground water data depicted in cross sectional views A - A' (Figure 3) and C - C' (Figure 4),the vertical extent of petroleum-Impacted ground water extends at least 90 feet bsg in the area of MW-1 and MW-5 and is not fully defined in any direction,based on an isoconcentration map (Figure 5) depicting the approximate extent of dissolved TPH-g at the site on 30 March 2001, the horizontal extent of dissolved hydrocarbons in First Water(screened between 20 and 50 feet bsg) is not fully delineated north, northeast, east, southeast and south of MW-7 The purpose for the proposed six CPT soil borings are to Identify the principal ground water flow units underlying the site, to assess the hydrocarbon-impact on each identified flow unit, to complete the vertical and horizontal assessment of impacted ground water and to obtain information to properly design a ground water monitoring system 23 REGIONAL GEOLOGIC SETTING The property is situated within the Great Valley Geomorphic Province of California, a large, elongate, north-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 . Jackson-Hallenbeck-Stockton (JHS) association The JHS soils are located within basins, and generally consist of moderate to poorly drained fine textured soils The soils are generally derived Advanced GeoEnvironmental,Inc I