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California Regional Water Quality Control Board <br /> Central Valley Region ;{ <br /> Robert Schneider,Chair <br /> Alan C.Lloyd,Ph.D. 1 Arnold <br /> Agency Secretary Sacramento Main Office 1 L ' Schwarzenegger <br /> 11020 Sun Center Drive#200,Rancho Cordova,California 95670 6114 Governor <br /> Phony(916)464-3291•FAX(916)464-4645e _ <br /> http://www.waterboards.ca.gov/centralvalley U�i. LO05 <br /> 5 December 2005 ENVIP?Oi-iiviL,`JT' fi ALTH <br /> PERNI!T'SERRVICES <br /> Mr. Darin Rouse Mr. Phil Johnson <br /> Chevron Products Company Sims-Group Management <br /> P.O. Box 6004 374 Lincoln Center <br /> San Ramon, CA 94583 Stockton, CA 95207 <br /> REVIEW, CHEVRON#9-6171, 6633 PACIFICA VENUE, STOCKTON,SAN JOAQUIN COUNTY <br /> I reviewed the 15 November 2005 Third Quarter 2005 Groundwater Monitoring Report(Report), submitted on <br /> behalf of Chevron Product Company(Chevron) by Secor International Inc. (Secor). The Report provides the <br /> results of quarterly groundwater monitoring conducted on 18 July 2005. Maximum groundwater concentrations <br /> were: Total Petroleum Hydrocarbons as gasoline (TPHg), 3,600 micrograms per Liter(gg/L), Benzene, 0.5 gg/L, <br /> MtBE, 0.5 gg/L, Tetrachloroethene (PCE), 10,000 gg/L, and Tricholoethene(TCE), 28 gg/L. Although TPHg <br /> was reported,the Report states the TPHg chromatographs did not exhibit the normal series of TPHg peaks in the <br /> C8 through C12 range,but did exhibit single peaks tentatively identified as "...characteristic of PCE and TCE. " <br /> The Report's Recommendations section includes a discussion of sampling and analyses for"...MtBE... <br /> TBA...other fuel oxygenates...EDB...1,2-DCA...methanol...ethanol", states "...None of these analytes have been <br /> detected at or above the lower detection limits during the past three sampling events... ", and requests <br /> "...quarterly sampling and analysis for these analyses be terminated... " The Report's Recommendations section <br /> also proposes a "...No Further Action Request for the site in 2006 "(NFA)based on the "...absence of TPHg, <br /> BTEX, and the common fuel oxygenates and additives... ". <br /> Comments: <br /> 1. The statement that "None of these analytes have been detected at or above the lower detection limits <br /> during the past three sampling events"contradicts the Report's detection of MtBE. However, I will <br /> reconsider your request for a reduction in analyses after reviewing the next monitoring report, which <br /> represents one hydrologic cycle (4 quarters) of sampling for the above-mentioned analyses. <br /> 2. In response to your comment proposing an NFA, you may submit a Closure Report to me, written in <br /> accordance with Tri-Regional Board Staff Recommendations for Preliminary Investigation and <br /> Evaluation of Underground Storage Tank Sites and the Appendix A—Reports, Tri-Regional Board Staff <br /> Recommendations for Preliminary Investigation and Evaluation of Underground Storage Tank Sites. <br /> These guidance documents may be downloaded from the website listed in the header of this letter. Upon <br /> receipt of the Closure Report,I will review and make a determination whether site closure is warranted. <br /> 3. Finally, I received an email on 28 November from your groundwater sampling subcontractor Bob Herron <br /> of Gettler-Ryan, stating that the Chevron Fourth Quarter of 2005 groundwater sampling event and the <br /> Chevron/Lincoln Center combined sampling of four Lincoln Center groundwater extraction wells are <br /> scheduled for 12 December 2005. Please include these results in the next Quarterly Report and the <br /> Closure Report. <br /> California Environmental Protection Agency <br /> 01 Recycled Paper <br />