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26 April 1999 AGE-NC Project No. 99-0592 Page 2of5 removal, soil samples were collected from the floors of the excavations at depths between 8 feet and 14 feet below surface grade (bsg). Total petroleum hydrocarbons quantified as gasoline (TPH-g) were detected at concentrations as high as 29,800 milligrams per kilogram (mg/kg); volatile aromatics(benzene, toluene, ethylbenzene and xylenes: BTEX) were detected at concentrations as high as 2,490 mg/kg; and methyl tertiary butyl ether(MTBE)was detected at concentrations as high as 9.1 mg/kg. Trichloroethene was also detected in a soil sample collected beneath UST (No. 4) at a concentrations of 220 mg/kg. Soil sample locations are depicted in Figure 2; Analytical results of soil samples are summarized in Tables 1, 2 and 3. 2.3. 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. 2.4. GROUND WATER DEPTH AND FLOW DIRECTION The estimated depth to ground water at the site is between 45 and 55 feet below surface grade (bsg) based on information from Lines of Equal Elevation of Groundwater - Lines of Equal Depth to Groundwater Fall 1997, published by the San Joaquin County Flood Control and Water Conservation District and from monitoring wells maintained by AGE at an adjacent site (Cherokee Truck Stop, 3535 East Cherokee Road). Based on review of a regional ground water elevation map published by San Joaquin County, the prevailing ground water flow direction near the site is generally toward the east-northeast, although flow directions may be both locally and seasonably variable. 3.0. SCOPE OF WORK Based on analytical results of soil samples collected during UST removal activities, further Advanced GeoEnvironmental,Inc.