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• 05 November 2007 AGE-NC Project No. 06-1481 Page 2 of 5 valley(Olmsted and Davis, 1961);the site itself is located on unconsolidated and semi-consolidated alluvium, lake, playa and terrace deposits of Quaternary age (California Division of Mines and Geology, 1977).Rocks composing the basement complex of the Province have not been completely defined but are believed to be metamorphic and igneous in origin. The Modesto, Riverbank and Turlock Lake Formations and overlying Recent alluvium are the principal sources of domestic ground water in the 13,500-square mile San Joaquin Valley Ground Water Basin(Basin 5-22).Based on a Fourth Quarter 2006 monitoring event at a property less than an eighth of a mile to the south-southwest from the site, Top Filling, 101 Wilson Way, Stockton, California, depths to ground water ranged from 37.98 and 40.60 feet below the top of the casing (btoc). The shallow and deep ground water was inferred to flow generally toward the northeast. However, this may be greatly modified by local recharge and discharge patterns. 2.2. UNDERGROUND STORAGE TANK REMOVAL A 22,000-gallon fuel oil tank(Fuel Oil#6) located approximately 35 feet from the northeast corner of the western-most building on Parcel 153-040-03 was filled in-place in 1986.A 1,000-gallon UST was removed from the southeast corner of the western building on Parcel 03 in 1986; soil contamination was found to be immediately below the tank and soil was over-excavated in the area of the tank. Confirmation sampling noted non-detect for all analytes and the site was closed by San Joaquin County Environmental Health in 1996. 2.3. PREVIOUS SITE ASSESSMENTS On 24 July and 25 July 2007, AGE advanced six soil borings (B-2 through B-7) in the areas of potential environmental concern identified during historical research to assess for possible contaminant-impacted soil and ground water beneath the site. Soil borings were advanced utilizing a van-mounted Geoprobe 5400 direct-push probing unit equipped with 1.25-inch probing rods;the Geoprobe advances soil probe borings using a hydraulic hammer to drive soil sampling tools to specified depths. Two borings (B-5 and B-7) were advanced to a depth of 10 feet below surface grade (bsg), and two borings (B-3 and B-4) were advanced to a depth of 20 feet bsg; only soil samples were collected from these borings. Soil borings B-2 and B-6 were advanced to total depths of 47 feet and 45 feet bsg, respectively; both soil and ground water samples were collected from these borings. The location of soil borings are illustrated on Figure 2. Nine soil samples(132-10,132-30,133-15, 134-10,134-15, 135-10, 135-20,136-35, and B7-10)and two grab ground water samples (132-W and 136-W) were submitted to Cal Tech Environmental Laboratories(CTEL),a California Department of Health Services-certified laboratory, for analysis Advanced GeoEnvironmental,Inc.