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Ms. Kama Harrigfeld - 2 - 13 November 2000 <br /> surface (bgs). AGE also found low level petroleum hydrocarbon contamination in deeper borings P8-10 <br /> and P23-10; however, the data do not show VOC contamination at 10 feet bgs in P23-10 (the only 10 <br /> foot sample analyzed for VOCs at the S&D building). Upon reviewing this information, an additional <br /> investigation is needed to determine the extent of contamination at the S&D building. Remedial actions <br /> may also be needed once the extent of the contamination is determined. <br /> During the meeting, the County chose to retain oversight of the underground storage tank (UST) <br /> investigation adjacent to the former truck lift building until delineation of contamination is complete. <br /> Board staff will provide regulatory oversight of the non-UST investigation. Also, staff agreed with the <br /> County and AGE on the following issues: <br /> • The well screens may extend to 20 feet in length due to the historic fluctuations in groundwater <br /> elevations; <br /> • EPA Method 8260 will be used for VOC soil analysis for consistency with previous data; and <br /> • AGE and the County stated that an aquitard was not found between the water table and the <br /> proposed terminal depth of the boring during drilling of wells at the UST investigation, so the we <br /> agreed that conductor casing is not needed. However, AGE needs to ensure that lower water <br /> bearing zones are not contaminated as a result of investigative activities and the wells will not act <br /> as a conduit for shallow contamination to enter the deeper zone. <br /> The work plan and addendum are hereby approved. By 27 November 2000,please provide a schedule <br /> to implement the work plan, complete investigation activities, and submit a site assessment report. We <br /> also request you provide Board staff with at least seven days notice prior to field activities, so staff may <br /> be present, if practical. Based on the results of the investigation, additional assessment may be necessary <br /> to delineate the extent of soil and groundwater contamination at the Site. <br /> If you have any questions, you may contact me at(916) 255-3119. <br /> SSICA HARDY <br /> Engineering Geologist <br /> cc: Mr. Mike Infurna, San Joaquin County Environmental Health Department, Stockton <br /> Mr. William Little, Advanced GeoEnvironmental, Stockton <br />