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..� April 2005 <br /> Chevron#9-6171 2 15 A p <br /> 6633 Pacific Ave., Stockton <br /> Comments: <br /> 1. The Report does not provide cross sections, isoconcentration maps, etc. that could facilitate an interpretation <br /> linking groundwater contamination found at your site to a source from the other named sites. Furthermore, <br /> MtBE is not detected in groundwater at the site. Therefore,the argument that the petroleum hydrocarbons are <br /> from other sites,because MtBE was found in only one soil sample, is simply an assumption without the <br /> information necessary to support your offsite source theory. Please provide this information as a revision to <br /> the SCM as you conduct future investigations. <br /> 2. The Report states one possible source of your site's petroleum hydrocarbon contamination,Former Norge <br /> Cleaning Village (Norge),had USTs. On page 29, the Report also states the chemicals of concern for the <br /> Norge site are PCE and trichloroethylene (TCE),which are chlorinated solvents,not petroleum hydrocarbons. <br /> I have conducted a search in GeoTracker, our statewide database, and could not find petroleum hydrocarbon <br /> data related to Norge. Please provide a source for that data. <br /> 3. There is some data showing that your petroleum hydrocarbon plume is commingling with PCE and TCE from <br /> the Lincoln Center. Their consultant LFR Levine Fricke monitors your wells (personnel communication, <br /> Secor) quarterly for chlorinated solvents, and the Report Table 3 shows PCE results from 1991 to 1998 in all <br /> monitoring wells, and TCE results in some monitoring wells. TCE is a chlorinated solvent breakdown <br /> (daughter)product of PCE(parent product), which formerly was used by dry cleaners. My letter of <br /> 22 February 2005 recommended that Lincoln Center and you coordinate sampling events and share data "...in <br /> order to provide a comprehensive overview of the two commingled groundwater plumes, Lincoln Center's <br /> PCE and Chevron's petroleum hydrocarbon." Please request copies of all split sample results from Lincoln <br /> Center, and update the PCE and TCE results in Table 3 in future monitoring reports. <br /> 4. The Report page 12 references Preliminary Remediation Goals (PRGs) "...set forth by the California State <br /> Environmental Protection Agency(CaIEPA). " The PRGs are referenced in Table 7. Table 7 footnotes a. and <br /> b. state the PRGs are "2002 USEPA Region IX... ". USEPA is not CalEPA. Currently CalEPA does not have <br /> PRGs, and the CHHSLs do not address groundwater or surface water. The Central Valley Region Water <br /> Quality Control Board Water Quality Goals (WQGs), not the PRGs, are used for comparison to analytical <br /> results for determining threats to water quality in our region. The WQGs (under Available Documents)may <br /> –be downloaded-from the4-nterr-et-website-in.the hear_1Pr..of this..letter,.— _ <br /> If you have any questions,you may call me at(916)464-4615 or email me at jbarton(a,waterboards.ca.jzov.. <br /> � 1•/N .I <br /> V. <br /> James L. L. Barton, P.G. <br /> Engineering Geologist <br /> cc: Mr. Mark Owens,UST Cleanup Fund, SWRCB, Sacramento <br /> Mr. Duncan Austin,RWQCB, Rancho Cordova <br /> Mr. Michael Infuma, San Joaquin County Environmental Health Department, Stockton <br /> Mr. George Forsythe, Secor International Inc., 3475 W. Shaw Ave., Ste. 104,Fresno, 93711 <br />