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California gional Water Quality Con l Board <br /> Central Valley Region <br /> Karl E.Longley,ScD, P.E.,Chair <br /> Linda S.-1 d.un s y, <br /> - Sacramento Main Orrice <br /> Arnol <br /> irarnrema/ 11020 Sun Center Drive#200,Rancho Cordova.California 956766114 Sch arzene <br /> /� gger <br /> 'Otec Itp,, Phone(916)464-3291 •PAX(916)464-4641 <br /> hnp://ww%v.waterboards.ca.gov/cennalvdley O Governor <br /> June 2, 2008 <br /> JUN D <br /> 6VV/R0 52008 <br /> Mr. Mark Adams pF4Nj/TS�&ATH <br /> Lincoln Center Environmental Remediation trust <br /> 137 Park Place <br /> Point Richmond, CA 94801 <br /> REVIEW OF SUBSTRATE INJECTION COMPLETION REPORT, PHASE V INTERIM <br /> REMEDIAL ACTION, LINCOLN CENTER, STOCKTON, SAN JOAQUIN COUNTY <br /> Staff of the Central Valley Regional Water Quality Control Board (Regional Water Board) has <br /> reviewed the "Substrate Injection Completion Report, Phase V Interim Remedial Action (IRA)," <br /> for Lincoln Center (the Site), Stockton. The report is dated April 30, 2008, and was received <br /> by the Regional Water Board May 1, 2008. LFR Environmental Consultants prepared the <br /> report on behalf of the Lincoln Center Environmental Remediation Trust (the "Trust"). <br /> The purpose of the report is to summarize the activities conducted to implement the Phase V <br /> IRA substrate injection event, and summarize the geochemical changes observed in the <br /> aquifer of the injection area during the first two months after substrate injection. Injection of <br /> 15,000 gallons of edible oil substrate (EOS), a degradable, carbon-based substrate, was <br /> conducted to bring about geochemical changes in groundwater down gradient of the source <br /> area in the vicinity of the Bank of Stockton. The EOS substrate is capable of creating a <br /> geochemical environment in the aquifer favorable for anaerobic processes that lead to <br /> enhanced reductive dechlorination (ERD) of tetrachloroethene (PCE), the contaminant of <br /> concern at the Site. The ERD treatment system is configured as a single row of injection wells <br /> intended to create a permeable reactive barrier to intercept and treat contaminants migrating <br /> down-gradient from the source area, and deliver substrate down gradient of the injection well <br /> barrier via natural groundwater flow. <br /> Staff has the following comments: <br /> 1. In the ERD Barrier and Treatment Zone Area, data collected from MW-108A suggests a <br /> strong preliminary response to injection from several lines of evidence: increase in Total <br /> Organic Carbon (TOC) concentration; increasing concentrations of trichloroethene <br /> (TCE), and cis-1,2-dichloroethene (cis-1,2-DCE) relative to PCE; decreasing dissolved <br /> oxygen (DO) and oxidation-reduction potential (ORP); and increasing manganese and <br /> iron. All lines of evidence indicate that ERD is occurring in the vicinity of MW-108A <br /> located in the center of injection well line. <br /> With the current monitoring program, ERD occurrence can only be documented in the <br /> center of the barrier in one A zone monitoring well. Minimal monitoring of the north and <br /> south edges of the injection barrier for multiple lines of ERD evidence should be added <br /> California Environmental Protection Agency <br /> h6lo 0 Recycled Paper <br />