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h 08 May 2008 AGE-NC Project No. 98-0465 Page 2 of 6 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 from both marine and non-marine mixed-rock sources. The Modesto, Riverbank, and Turlock Lake Formations and overlying Recent alluvium are the principal source of domestic ground water in the 13,500 square-mile San Joaquin Valley Ground Water Basin (Basin 5-22). This basin is drained primarily by the San Joaquin River. The nearest surface water feature in the vicinity of the property is the Smith Canal, located approximately 1,000 feet south of the site. Based on a review of the map Lines ofEqual Depth to Groundwater Fall 1998,published by the San Joaquin County Flood Control District and Water Conservation District(FCD&WCD),the estimated depth to ground water at the site is between 10 and 20 feet below surface grade(bsg).The map Lines ofEqual Elevation of Groundwater Fall 1997(FCD&WCD)depicts the regional ground water flow direction to be toward the northeast. 2.2. UNDERGROUND STORAGE TANK REMOVAL On 05 March 1999, one 10,000-gallon diesel UST and two 10,000-gallon gasoline USTs and associated fuel dispensers and product piping were removed from the site.Laboratory analysis of soil samples collected from beneath the former UST areas detected total petroleum hydrocarbons quantified as gasoline and diesel(TPH-g and TPH-d,respectively)at concentrations up to 300 mg/kg (milligrams per kilogram). Volatile aromatic compounds benzene, toluene, ethylbenzene, and xylenes (BTEX) were detected at concentrations up to 0.29 mg/kg; methyl tertiary-butyl ether (MTBE)was detected in soil samples at concentrations up to 0.54 mg/kg. Laboratory analysis ofthree grab ground water samples collected from beneath the former UST areas detected dissolved TPH-g at concentrations up to 5,900 µg/1 (micrograms per liter); BTEX compounds were detected in grab ground water samples at concentrations up to 0.29 µg/1; MTBE was detected in grab ground water samples at concentrations up to 0.54 µ9/1. 2.3. PREVIOUS SITE ASSESSMENT ACTIVITIES Four ground water monitoring wells were installed on the site on 10 July 2000. A total of 8 soil samples were collected and analyzed for TPH-g, TPH-d, BTEX, MTBE, and the suite of five oxygenated fuel additives by EPA Method 8260 Modified. None of the analytes were detected at Advanced GeoEnvironmental,Inc.