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Michael Collins <br /> September 3. 1993 <br /> Page 4 <br /> and depths will be determined in the field jointly by BC and Count of San Joaquin. <br /> ,. J Y <br /> Department of Environmental Health (County) personnel. Samples will be analyzed for <br /> TPH-G. 'TPH-D, TPH-MO, and BETX by an analytical laboratory certified by the State of <br /> California. <br /> Prior to backfilling, the base of the excavation should be lined with approximately two feet <br /> of a low permeability clay and five feet of clean imported soil. The remainder of the <br /> excavation should then be backfilled with the materials currently stockpiled on-site. BC will <br /> K collect three composite samples, at locations approved by, the County. from the stockpiled <br /> material and submit these samples for laboratory analysis. Samples will be analyzed for <br /> soluble threshold limit concentration (STLC) of TPH-G and TPH-D to confirm that petroleum <br /> products contained in the soil are not leachable. Upon confirmation of the leachability of the <br /> Po y <br /> soil, the site will then be returned to its original condition by backfilling and compacting the <br /> excavation with on-site material to just below ground level; then re-asphalting the entire area <br /> to meet existing grade. <br /> BC also recommends installing three groundwater monitoring wells to monitor the shallow <br /> water-bearing unit for the presence of TPH-G and TPH-D. The three groundwater wells will <br /> be installed to approximately 100 feet below ground level and monitored on auarterl basis <br /> 9 Y <br /> �- for a period not to exceed two years. If analytical result indicate nondetectable concentration <br /> L7 of TPH-G and TPH-D in groundwater for a period of four consecutive quarters prior to the <br /> end of the two year monitoring period, the monitoring program will be discontinued at that <br /> time. <br /> If you have any questions regarding this status report, please call me at (916) 444-0123. <br /> Sincerely; <br /> l <br /> I <br /> BROWN AND CALDWELL <br /> J � � <br /> Pat G. Cullen <br /> jProject Manager <br /> PGC:TM:lk <br /> Enclosure? I <br /> l <br /> Lcc: Ms. Tina Bauer, Brown and Caldwell t <br /> Mr. Bob Fratto, Sheldon Oil <br /> Mr. Les Smith. Kause Construction <br /> Mr. Jaynes WOodard. Sheldon Oil l <br /> ' 1 <br /> i <br /> Use or disclosure of data contained on this sheet is subject to lite restriction specified at the beginning of this <br /> document. <br /> Brown and Calriweil 7603,,COR32ESPA7503-M.L-1 <br />