SITE INFORMATION AND CORRESPONDENCE

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/9� Ms. Penny Fottrell GEOMATRIX Chevron Environmental Management Company February 12, 2003 Page 4 (USCS) as presented in the American Society of Testing and Materials (ASTM) Standard D2488-90. Geomatrix proposes to collect grab groundwater samples from all of the borings, at a four-foot sample interval selected between 35 and 60 feet bgs, which is within the interval where petroleum-impacted soil has been previously identified at the site. Additionally, a grab groundwater sample will be collected from boring SB-15 at a depth of 80 feet bgs. Ground- water samples will be collected by advancing a hydropunch tool through the center of the sonic drill casing ahead of the drilling apparatus, exposing a four foot screen, then using a dis- posable bailer to collect a sample. The sample will be decanted into 1-liter amber bottles and 40 milliliter acidified volatile organic analysis vials provided by the laboratory. Samples will be labeled, stored in ice-filled coolers, and delivered to a state-certified analytical laboratory under Geomatrix chain-of-custody procedures. Following sample collection, the borings will be backfilled with grout in accordance with San Joaquin County and Stanislaus County requirements. ANALYTICAL METHODS The soil samples collected will be analyzed for total petroleum hydrocarbons quantified as crude oil (TPHc) using Environmental Protection Agency(EPA)Method 8015 Modified; for benzene, toluene, ethylbenzene, and xylenes (BTEX) using EPA Method 8021; and for polynuclear aromatic hydrocarbons (PAHs) using by EPA Method 8270 SIM. Groundwater samples will be submitted for analysis of TPHd using Environmental Protection Agency(EPA) Method 8015 Modified; for BTEX using EPA Method 8021; and PAHs using EPA Method 8270 SIM. The laboratory will perform the TPHd analyses both with and with- out a silica gel preparation procedure prior to analysis (EPA Method 3630 Modified). REPORTING AND SCHEDULING Upon completion of field activities and receipt of laboratory analytical results, Geomatrix will prepare a report documenting field activities and summarizing analytical results for submittal to ChevronTexaco. The report will contain tables and figures summarizing recent and histori- cal data., Mobilization of the drill rig is estimated to occur approximately 2 weeks following approval to access the adjacent properties. After samples are collected, laboratory data will be avail- able and evaluated within 4 weeks. Four weeks following receipt of data a draft report will be available for ChevronTexaco.