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ATC Associates Inc. <br /> (Wk <br /> �� 1117 L`tine Palm Avenue, Suite 201 <br /> Modesto, California 95351 <br /> 209-579-2221 <br /> AS SO C I ATE S I N C . <br /> fax: 209-579-2225 <br /> The soil samples were collected continuously in 2 inch macro core sampler containing a five <br /> foot acetate tube. The samples and drill cuttings were characterized for soil type, moisture <br /> content, and visual evidence of petroleum hydrocarbons. A photo-ionization detection meter <br /> (PID) was used as a field-screening device for the detection of petroleum hydrocarbon vapors <br /> in drill cuttings and cored samples. <br /> 4.2 Soil Sample Analysis <br /> Collected soil samples were placed on ice and selected samples from approximately 14.5 feet <br /> bgs were transported under chain-of-custody to State-Certified Argon Laboratories Inc. <br /> Environmental Laboratory Accreditation Program (ELAP Cert. No. 2359) in Ceres, California for <br /> analysis. <br /> The soil samples were analyzed for total petroleum hydrocarbons as diesel (TPHd) utilizing <br /> EPA Method 8015M. The analytical results for soil samples are discussed in Section 4.6. <br /> 4.3 Groundwater Sample Analysis <br /> Samples were collected from the first encountered groundwater at approximately 15 feet bgs. <br /> Upon completion of sample collection the borings were grouted to surface. <br /> All collected groundwater samples were placed on ice, and transported under chain-of-custody <br /> to State-Certified Argon Laboratories Inc. in Ceres, California for analysis. <br /> The groundwater samples were analyzed for total petroleum hydrocarbons as diesel (TPHd) <br /> utilizing EPA Method 8015M, benzene, toluene, ethylbenzene, total xylenes (BTEX), methyl- <br /> tert-butyl ether (MTBE), di-isopropyl ether (DIPE), ethyl tert-butyl ether (ETBE), tert-amyl methyl <br /> ether (TAME), 1,2-dichloroethane (1,2-DCA), and 1,2-dibromoethane (EDB). The analytical <br /> results for groundwater samples are discussed in Section 4.7. <br /> 4.4 Regional Geology <br /> The site is situated at an approximate elevation of approximately 10 feet above mean sea level, in <br /> the Great Valley geomorphic province. The Great Valley province is a north-south elongated <br /> structural trough filled with sediment from marine and continental sources. The continentally <br /> derived sedimentary deposits comprise the upper portion of the valley fill, and were deposited in <br /> fluvial, alluvial, and lacustrine environments. <br /> 4.5 Site Geology <br /> Soil previously encountered in borings for wells SB1, SB2 and SB3 generally consisted of clays <br /> to a depth of 14 feet bgs, with a sandy layer present from 14 feet to 15 feet bgs. Below the <br /> sand, soil consisted primarily of clay to a depth of 20 feet, the maximum depth advanced. <br /> 4.6 Soil Analytical Results <br /> TPHd was not detected in the soil samples collected at approximately 14.5 feet bgs from boring <br /> SB1, SB2 or SB3. <br /> S:\Enviromental\39426\reports\Subsurface inv.doc 2 <br />