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1 <br /> Thrifty Oil Company#171 <br /> 1250 N. Wilson Way, Stockton CA page 2 <br /> February 18, 2010 <br /> • It has not been demonstrated that the groundwater plume is oxygen deficient and that <br /> oxygen deficiency is the controlling factor for bioremediation at this site. <br /> • It has not been demonstrated that the subsurface conditions are not toxic and are <br /> capable of supporting biological growth. Enhanced bioremediation is only feasible if <br /> proper biological agents are present at the depths to be targeted by the ORC socks and <br /> that this life would benefit (be enhanced) by the addition of oxygen. <br /> The FS is inadequate and not approved as submitted. [H&S 25296.10(c)(3)]. A revision is <br /> required that addresses the concerns noted above. Please submit a revised FS to Geotracker <br /> by April 1, 2010. <br /> The revision is to also provide a method that will allow groundwater samples to be collected in <br /> the plume area that is not from the injection points. The EHD is concerned that groundwater <br /> samples collected from the injection points would represent groundwater conditions in, or <br /> immediately surrounding, the actual well casing and may not be representative of the <br /> groundwater conditions further out in the extended areas of the plume, between the other wells <br /> included in the plan. <br /> To establish a baseline prior to testing the effectiveness of ORC socks in the groundwater, the <br /> EHD directs TOC to analyze groundwater samples from wells, TB-7, EW-5S, and EW-5D for <br /> dissolved oxygen. The results of this testing are to be submitted to Geotracker during the <br /> second quarter, 2010. <br /> The Central Valley Regional Water Quality Control Board (CVRWQCB) requires all sites <br /> proposing to add chemicals into the subsurface/groundwater to apply for a permit. Please <br /> contact Mr. James Barton at (916) 464-4615 to determine the steps needed to have your ORC <br /> proposal evaluated for Waste Discharge Requirements (WDRs) and to meet general permit <br /> requirements. Insitu pilot testing of ORC socks can only be conducted after WDRs have been <br /> evaluated and approved by the CVRWQCB. <br /> If you have any questions, please contact Michael Infurna at (209) 468-3454. <br /> xz"r- <br /> Michael J. Infurna Jr., REHS Nuel C. Henderson Jr., PG <br /> Senior Registered Environmental Health Specialist Engineering Geologist <br /> c: Mr. James L. Barton, CVRWQCB, Underground Storage Tank Unit, 11020 Sun Center <br /> Drive, #200, Rancho Cordova, CA 95670-6114 <br /> Mr. Mark Owens, SWRCB, Division of Clean Water Programs, Underground Storage <br /> Tank Program, P.O. Box 944212, Sacramento, CA 94244-2120 <br />