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Californ*Regional Water Quality fwntrol Board <br /> Central Valley Region <br /> Katherine Hart, Chair 0 <br /> Linda S. AdamsArnold <br /> Secretary for 11020 Sun Center Drive#200,Rancho Cordova,California 95670-6114 Schwarzenegger <br /> Environmental Phone(916)464-3291 •FAX(916)4644645 Governor <br /> Protection hftp://www.waterboards.ca.gov/centralvalley <br /> Ms. Eugenia Valdez 8 Der�{r ffdF=1VED <br /> J&L Market �H(�tc� <br /> 8125 EI Dorado Street <br /> French Camp, CA 95231 PH 10 2010 <br /> DOCUMENT REVIEW, JBL MARKET, 8125 S. EL DORADO ST., FRENCHVAAllDWEN1AL HEALTH <br /> SAN JOAQUIN COUNTY, CASE NO. 390897 PEPA41 WRACES <br /> I reviewed the Ozone Injection Remediation System Work Plan (Workplan) received <br /> 25 October 2010 from your consultant ATC Associates, Inc (ATC). The Workplan was written in <br /> response to my 9 June 2010 letter request for the Workplan, and provides the scope of work for <br /> the installation of three additional ozone sparge nested wells (OS3 through OS5), each screened in <br /> two aquifer zones from 67' to 72' below ground surface (bgs) and from 83' to 88' bgs. The new <br /> sparge wells, located in the northern portion of the groundwater plume, will supplement the two <br /> existing ozone sparge wells (OS1 and OS2) used in the December 2009 pilot test conducted at <br /> your site. The pilot test lasted four weeks, and was deemed successful as petroleum <br /> hydrocarbons reductions (68% to 89%), increased dissolved oxygen and oxidation reduction <br /> potential, and minimal secondary effects (hexavalent chromium increased to 0.25 micrograms per <br /> Liter after 4 weeks)were observed. The groundwater plume is delineated by groundwater <br /> monitoring as onsite and stable. The 2 June 2010 Ozone Sparge Well Installation and Pilot Study <br /> Test Report recommended installation of additional sparge wells in the northern portion of the <br /> groundwater plume to complete remediation, as OS1 and OS2 appear to be properly oriented to <br /> address the southern portion of the groundwater plume. <br /> On 11 November 2010, 1 requested that ATC move up the scheduled semi-annual groundwater <br /> monitoring event to November 2010, in order to evaluate the Workplan with more recent <br /> groundwater data. On 6 December 2010, 1 received the requested data by email from ATC. <br /> Groundwater concentrations have declined and remained low since completion of the pilot test; <br /> hence, additional remediation is no longer necessary for your site. With the most recent data, site <br /> closure maybe appropriate for this case. Please submit a closure report by 28 February 2011, <br /> written in accordance with Appendix A — Reports, Tri-Regional Board Staff Recommendations For <br /> Preliminary Investigations and Evaluation of Underground Tank Sites, 16 April 2004, which may be <br /> downloaded electronically from our website at: <br /> http://www.waterboards.ca.gov/centralvalley/water issues/underground storage tanks/tri- <br /> regionals appendix a.pdf. <br /> Upon my review of the closure report, additional directions for continuing the closure process will <br /> be provided to you. You may contact me regarding questions by phone at (916) 464-4615; or by e- <br /> mail at ibarton( waterboards.ca.gov. <br /> /James L.L. Barton, P.�. <br /> Engineering Geologist <br /> cc: Mr. Michael Infurna, San Joaquin County Environmental Health Department, Stockton <br /> Mr. Todd Hafner, ATC Associates, Inc., 1117 Lone Palm Ave., Ste. 201, Modesto 95351 <br /> California Environmental Protection Agency <br /> Qd Recycled Paper <br />