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URS <br /> Ms. Devra Lewis <br /> Regional Water Quality Control Board <br /> November 11, 2002 <br /> Page 2 of 2 <br /> 4. Methanol will be analyzed in soil borings HA-19 and GP-10 in the AST area. Methanol will <br /> not be analyzed in the remainder of the soil borings as originally proposed in the work plan <br /> because methanol was reported below detection limits (1.0 mg/kg) in all but one soil sample <br /> collected from soil borings N-1, MW-14, and W-2 during the installation of wells for the <br /> aquifer pump test conducted in May 2002. The sample collected from boring W-2 at 10 ft bgs <br /> reported a concentration of 1.2 mg/kg methanol,just above the detection limit. <br /> 5. The number of groundwater samples analyzed for methanol will be reduced from 50 to 29. <br /> Methanol will be analyzed in borings HP-18, GP-13 through GP-22, HP-19 and HP-20, HP- <br /> 22, and HP-26 in efforts to delineate the extent of methanol in groundwater. Methanol <br /> analyses have been reduced to select boring locations because minimal methanol (580 to 970 <br /> ug/1)has been detected on-site and the selected boring locations should be sufficient to <br /> delineate the methanol in groundwater. <br /> Since the postponement of the Subsurface Investigation occurred in August, site access <br /> agreements have been secured with the neighboring properties. Pending the receipt of letters of <br /> authorization to perform work on all off-site properties and the approval of drilling permits,the <br /> drilling will be scheduled to commence during the weeks of November 18 and 25, 2002. We <br /> anticipate that the Subsurface Investigation Report will be submitted by February 7, 2003. <br /> If you have any questions regarding this response letter, please do not hesitate to contact me at <br /> (510) 874-3057. <br /> Sincerely, <br /> URS CORPORATION <br /> Amy Breckenridge, P.E. <br /> Project Manager <br /> cc: Margaret Lagorio, San Joaquin County Public Health Services <br /> Tracy Sizemore, Tosco Corporation <br /> Jeff Goold, Equiva Services LLC <br /> \PROTECTS\Stockton\RWQCB\subsurf inv response doe <br />