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Boyett Petroleum January 15, 2001 419 South Main Stree4 Manteca, California Page 6 ' Interim Report of Findings for Lateral Extent of Groundwater Contamination Soil samples collected for analysis were analyzed using EPA method 5030/LUFT for ' gasoline petroleum hydrocarbons, EPA method 8260B for BTX&E compounds, oxygenates, EDB and 1,2-DCA. The minimum detection limits used for each analyte was 1.0 mg/Kg for gasoline, 5.0 ug/Kg for BTX&E, 10 ug/Kg for Methyl Tertiary-Butyl Ether (MTBE), 400 ug/Kg for Ethanol, 200 ug/Kg for Tertiary- Butanol, 10 ug/Kg for Di-Isopropyl Ether (DIPE), Ethyl Tertiary-Butyl Ether (ETBE), Tertiary-Amyl Methyl Ether (TAME), and Ethylene Dibromide (EDB), and 5.0 ug/Kg for 1,2-Dichloroethane (1,2-DCA). Analyses were conducted by GeoAnalytical Laboratories, Inc. a State certified laboratory in Modesto, California. All samples were recorded on a Chain of Custody and placed in an Ice Chest cooled with real ice (Blue Ice® once it was demonstrated to the SJC PHS/EHD inspector ' that 5°C or below can be maintained with the use of Blue Ice®) for transport to the lab. 4.0 Soil Anal tical Results y , . The soil sample analysis indicated no detectable levels of gasoline, BTXE, oxygenates, EDB or 1,2-DCA. A total of twelve (12) soil samples were collected and analyzed from the boring/monitoring wells and the results were all none-detected for all analytes tested. This included samples taken at the capillary fringe, which was at approximately 16 -- 16 1/2 feet below ground level (bgl) in MW-5, MW-6, MW-7, and MW-8, and were none-detected for all analytes tested. ' 5.0 Geology The subject property is located on the western side of California's Central Valley. The Central ' Valley is approximately 400 miles long and averages 50 miles wide encompassing approximately 20,000 square miles. The valley is a large asymmetric trough that is bounded by granitic, metamorphic and marine sedimentary rocks of pre-tertiary age. This trough has been filled with as much as 30,000 feet of sediment in the San Joaquin Valley portion to the south, and as much as 60,000 feet of sediment in the Sacramento Valley portion to the north. The age of the sediments range from Jurassic to Holocene and include both marine and continental rocks and sedimentary deposits(Olmstead and Davis, 1961). 1 Manteca lies in the Central Valley Physiographic Province of California. The Valley is approximately 50 miles wide. It is bounded to the west by the foothills of the Coast 1 1