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I <br />' screened interval from approximately 193 feet bsg to 198 feet bsg <br />' A total of 28 soil samples were analyzed The highest concentrations of petroleum hydrocarbon <br /> compounds were detected from soil samples collected at between 40 and 60 feet bsg,in HU-1 Middle <br /> Zone TPH-g was detected in soil samples collected from soil borings MW-4, MW-5 and B-2 at <br />' concentrations as high as 4,500 milligrams per kilogram(mg/kg)(MW4-58),3,600 mg/kg(MW5-50) <br /> and 2,000 mg/kg(B2-50) <br />' The BTEX compound benzene was detected in soil samples collected from MW-4, MW-5 and B-2 <br /> at maximum concentrations of 33 mg/kg (MW4-58), 21 mg/kg (MW5-50) and 20 mg/kg (B2-50), <br /> toluene was detected at maximum concentrations of 180 mg/kg(MW4-58), 100 mg/kg (MW5-50) <br /> and 54 mg/kg (B2-50), ethylbenzene was detected at maximum concentrations of 19 5 mg/kg <br /> (MW4-58),30 mg/kg(MW5-50)and 13 mg/kg(B2-50),and total xylenes were detected at maximum <br /> concentrations of 224 mg/kg (MW4-58), 182 mg/kg (MW5-50) and 77 mg/kg (B2-50) <br /> Fuel additives including DIPE, ETBE,MTBE, TAME,TBA,EDB and 1,2-DCA were not detected <br /> in the soil samples collected and analyzed from the three soil borings Additional VOCs detected in <br /> the analyzed samples included isopropylbenzene, n-propylbenzene,1,3,5-tnmethylbenzene, 1,2,4- <br /> tnmethylbenzene p-isopropyl-toluene and naphthalene <br /> REGIONAL GEOLOGIC SETTING <br /> According to the Geologic Map of California, published in 1977 by the State of California <br /> Department of Mines and Geology,the site area is within the Great Valley Geomorphic Province of <br />' California, a large, elongate, northwest trending structural trough The Great Valley Province has <br /> been filled to its present elevation with thick sequences of sediment ranging in age from Jurassic to <br /> present day,creating a nearly flat lying alluvial plain extending from the Tehachapi Mountains in the <br /> south to the Klamath Mountains in the north The western and eastern boundaries of this province <br /> are comprised of the California Coast Range and the Sierra Nevada Mountains, respectively The <br /> Great Valley Province is subdivided into two mayor divisions designated the Sacramento and San <br /> Joaquin Valleys <br /> Based on the General Soil Map from the San Joaquin County Soil Survey,published by the United <br /> States Department of Agriculture Soil Conservation Service in 1992, the site area is within the <br /> Jacktone-Ho llenb eck-Stockton (JHS) association The JHS soils are located within basins, and <br /> generally consist of moderate to poorly drained fine textured soils The soils are generally derived <br /> rfrom both marine and non-manne sediment,and are generally formed in alluvium derived from mixed <br /> rock sources <br /> GROUND WATER DEPTH AND GRADIENT <br /> According to the map titled Lines Of Equal Depth Of Water Wells-Fall 1996, published by the San <br /> Joaquin County Flood Control and Water Conservation District,the estimated depth to ground water <br /> • at the property is approximately 20 to 30 feet below surface grade(bsg) The prevailing ground water <br /> I <br /> I <br />