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Western Regional Operations <br /> EA ENGINEERING 41 Lafayette Circle <br /> SCIENCE, AND Lafayette,California 94549 <br /> TECHNOLOGY, INC. (415)283-7077 <br /> 2 February 1988 <br /> Laurie L. Cotulla <br /> San Joaquin Local Health District <br /> 1601 E. Hazelton Avenue <br /> Stockton, California 95201 a tiggg <br /> FEB <br /> RE: Proposed Protocol For Well Installation NTAt HEALTH <br /> and Sampling At EXXON Retail Site 7-3942 EN,41ROME. VICES <br /> 4444 N. Pershing Avenue, Stockton, CA FERMIT/SER <br /> Dear Ms. Cotulla: <br /> EA Engineering, Science, and Technology, Inc. (EA) has been <br /> retained by EXXON Company, U.S.A. to investigate the extent of <br /> soil and/or ground water contamination off-site the former EXXON <br /> Retail Site 7-3942, located at 4444 N. Pershing Avenue, Stockton, <br /> California. To determine the extent and level of potential <br /> ground water and soil contamination, installation of four, off- <br /> site monitoring wells are proposed. Proposed well locations are <br /> shown in Figure 1 . <br /> In accordance with San Joaquin County and California Regional <br /> Water Quality Control Board guidelines for monitoring underground <br /> storage tanks for hazardous substances, the holes will be drilled <br /> to a depth of approximately 30 feet--20 feet below the estimated <br /> static water level or, if dry, to a maximum of 45 feet . However, <br /> if at least 5 feet of competent clay exists below the water <br /> table, the wells will be terminated 1 to 2 feet into this clay. <br /> The bore holes will be drilled with a hollow-stem auger. All <br /> soil cuttings will be placed in 55-gallon drums and remain on <br /> site until after soil analysis has determined the total petroleum <br /> content of the soil . During drilling, soil samples will be <br /> collected every 5 feet from 5 feet below the surface to the total <br /> depth of the bore hole, using a California modified split spoon <br /> sampler with brass liner. Between samples the downhole equipment <br /> will be steam-cleaned or washed with a trisodium phosphate <br /> detergent and then rinsed with tap water, and distilled water. <br /> All soil samples will be screened for hydrocarbon content with an <br /> organic vapor analyzer (OVA) . After collection and screening, <br /> the sample will be capped with aluminum foil and PVC caps, placed <br /> on ice, and shipped to a state-certified analytical laboratory <br /> within 24 hours. The soil samples collected from just above the <br /> water table and samples with detectable fuel contamination will <br /> be analyzed for total petroleum hydrocarbons (TPH) and selected <br /> volatile gasoline constituents (VOA) , using modified EPA 8015, <br /> 8010, 8020, 8240, 602, and GC-FID methods as appropriate. Soil <br /> borings will be logged by a supervising geologist and described <br /> according to the Unified Soil Classification System. <br /> EXX10:73R <br /> BALTIMORE 0 CHICAGO 0 CINCINNATI ❑ LINCOLN ❑ NEW YORK 0 SAN FRANCISCO <br />