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1 California F jional Water Quality Cor ' of Board ' ` , <br /> Central Valley Region f��; <br /> Karl E. Longley, ScD, P.E., Chair <br /> o <br /> Linda S. Adams Arnold <br /> Secretary for 11020 Sun Center Drive#200, Rancho Cordova, California 95670-6114 Schwarzenegger <br /> Environmental Phone (916) 464-3291 • FAX (916) 464-4645 Governor <br /> Protection http://www.waterboards.ca.gov/centraIvalley <br /> 23 December 2008 <br /> UtG 211 9 t4308 <br /> Mr. Matt Gabris <br /> Sara Lee Bakery Group, Inc ENVIROM-m[,dr 1HEAITIj <br /> 3500 Lacey Rd. PERMIT/SERVICES <br /> Downers Grove, IL 60515 <br /> DOCUMENT REVIEWS, FORMER COLUMBO/TOSCANA BAKERIES, 1444 S. LINCOLN <br /> STREET, STOCKTON, SAN JOAQUIN COUNTY(REGIONAL BOARD CASE# 390825) <br /> 1 reviewed the Sara Lee Bakery Group, Inc. (Sara Lee) Feasibility Study and Remedial <br /> Evaluation (Report), received 1 December 2008 from your consultant PSC Environmental <br /> Services Inc. (PSC). The Report, submitted in response to my 15 August 2008 letter (Letter), <br /> evaluates the following four (4) potential remediation technologies for the impacts from the <br /> underground storage tanks (USTs) removed in 1994, using existing soil and groundwater data <br /> compared with geological cross sections. <br /> 1. Soil Vapor Extraction/Air Sparging (SVE/AS), <br /> 2. Soil Excavation (SE) and offsite disposal, <br /> 3. In-Situ Chemical Oxidation (ISCO), and <br /> 4. BioSparging (BioS) <br /> The Report provides a comparison in text and a summary table of the expected effectiveness <br /> over the short-term and long-term, with the estimated cost for each technology. The limited <br /> size of the project area (30' by 30' parking lot) and potential limited access inside the <br /> warehouse for additional remediation, if warranted, were presented as possible hindrances to <br /> active remediation. <br /> The Report Summary and Conclusions section is condensed below: <br /> • SVE/AS received a variable (limited to good) short-term effectiveness rating (dependant <br /> upon site permeability) and a limited long-term effectiveness, due to reported similar <br /> Sara Lee and other SVE/AS sites reaching asymptotic levels without effectively <br /> reducing contaminant concentrations in soil. SVE/AS was estimated to cost from <br /> $327,000 (outside of building) to $447,000 (inside and outside of building). <br /> • SE in the source area down to the current water table at 20 feet below ground surface <br /> (bgs) would require an engineered installation of shoring for the sidewalk and building, <br /> and a street lane closure due to limited site access, with offsite removal of 666 cubic <br /> yards of contaminated soil. SE received a minimal short-term effectiveness rating (due <br /> to "secondary sources" reported below the water table) and minimal long-term <br /> effectiveness rating (limited effect on the existing groundwater plume), at a cost <br /> California Environmental Protection Agency <br /> 0a Recycled Paper <br />