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LMO� 02 October 2000 AGE-NC Project No. 00-699 Page 2of8 well is located approximately 50 feet northeast of the former UST cluster. Prominent site features, including the former UST cluster location and the domestic well, are,illustrated in Figure 2. r , 2.2. UNDERGROUND STORAGE TANK REMOVAL According to information obtained from the PHS-EHD (Espana's Supplemental Preliminary Site Investigation for State Route 99/Hammer Lane to Mark Thomas & Co., Inc.November 17, 1999), three 8,000-gallon gasoline USTs and associated dispensers were removed from the site in December 1980. The former location of the tank cluster is illustrated on Figure 2. The PHS-EHD had no records regarding the UST removal nor associated sampling, if performed. 2.3. CALTRANS SITE INVESTIGATION 1„r In October 1999,Espana supervised the advancement and sampling of three soil borings within the former UST cluster.The borings were advanced as part of a proposed CalTrans investigation for the expansion of the Highway.99 -Hammer Lane interchange. The three borings, EGC-1, EGC-2 and EGC-3, were advanced to depths of 21.5 feet, 66 feet and 26.5 feet bsg, respectively. A total of nine soil samples and one grab ground water sample were submitted to a laboratory for analysis oftotal petroleum hydrocarbons quantified as gasoline(TPH-g) and diesel(TPH-d)and volatile aromatic compounds-benzene,toluene,ethyl benzene and xylenes (BTEX). Concentrations of petroleum hydrocarbons in soil samples collected from soil borings EGC-1 and EGC-2 were below detection limits. TPH-g and TPH-d were reported in five soil samples from IMP EGC-3 at concentrations ranging from 1.70 mg/kg to 2,390 mg/kg.BTEX compounds were reported in three soil samples at concentrations ranging from 0.0249 mg/kg to 239 mg/kg. TPH-d (0.173 V µg/L)was the only target analyte reported in the water sample submitted for analysis.Contamination was detected to total depth(26.5 feet bsg) in boring EGC-3. 2.3. 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 Advanced GeoEnvironmental,Inc.