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LTH HEPUBLIC A SERVICES <br /> .oG <br /> SAN JOAQUIN COUNTYor X <br /> ENVIRONMENTAL HEALTH DIVISION 6 <br /> ! Ernest M. Fujimoto, N .D., M.P.H., Acting Health Officer c�.. iP <br /> gci o'6r' <br /> 445 N. San Joaquin Street • P.O. Box 388 • Stockton, CA 95204-0 <br /> (209) 468-3420 n i <br /> v <br /> MARY LEHR ; <br /> 1250 EDGEWOOD DRIVE MAR 2 4-1994 <br /> LORI CA 95240 <br /> RE: Arts and Artists SITE CODE: 2423 <br /> f 204 East Lodi Ave <br /> Lodi CA 95240 i <br /> San Joaquin County Public Health Services,Environmental Health Division(PHS/EHD)has completed review i <br /> of the 'Problem Assessment Report*dated January 1994 and prepared by Geological Audit. PHS/EHD has <br /> the following comments for your consideration. <br /> The Problem Assessment Report(PAR)described the soil and groundwater investigation to date and various <br /> remedial feasibility tests including: vapor extraction and aquifer permeability. The PAR also evaluated <br /> remedial alternatives and suggested preferred alternatives to implement as part of a final remediation plan. <br /> Soil <br /> The,}extent of soil contamination is still relatively undefined. Both monitoring well, MWl, and vapor <br /> extraction well, RW1, evidenced soil contamination from 15 feet below ground surface (bgs) to 48.2 vertical <br /> feet.bgs. Soil contamination of up to 22,000 ppb benzene was documented at 16.2 feet bgs and 1,700 ppb <br /> benzene at 50 beet bgs. The horizontal definition of the soil contamination is in question, since the nearest <br /> soil jboring, MW3, was installed approximately 30 feet away from MWl and RWl and the only sample <br /> collected for laboratory analysis in 1987 was at 45.7 feet bgs. The next closest soil information was obtained <br /> approximately 40 feet away during the installation of MW4 and the soil samples collected for analysis were <br /> between 40 and 55 feet bgs. It was estimated that there was 5,000 cubic yards of contaminated soil beneath I <br /> the site. Once remediation is initiated it will be necessary to obtain further soil information in order-to <br /> monitor the effectiveness of the remediation system selected and to verify the extent of soil contamination. <br /> The'PAR included an evaluation of various soil remediation methods. The alternative selected to pursue for <br /> the soil portion of the final remediation plan was vapor extraction. The results of the vapor extraction test <br /> indicate that the site has sufficient soB permeability for in-situ vapor extraction to be an effective remediation <br /> technology for use at the site. Based on interim investigation,it may be necessary to install additional vapor <br /> extraction wells which are selectively screened to accommodate various lithological changes which have.been <br /> identified at the site, <br /> Groundwater <br /> Eight monitoring wells, MWl - MW8, have been installed to investigate the extent of groundwater <br /> contamination. MW2 and MW3 have not been sampled since 1987, yet periodically MW3 has contained <br /> sufficient groundwater to sample. In order that the plume of groundwater contamination be better <br /> characterized MW3 should be sampled whenever possible. The installation of MW5,MW6,MW7,and MW8 <br /> have determined the boundaries of groundwater contamination. <br /> TheIboring logs and relative casing elevation should have been included in the PAR for MW1, MW2, and <br /> MW3. Please submit this information as addendum to the PAR The volume of contaminated groundwater <br /> was estimated to be 308,269 gallons. <br /> E A Division or San.Joaquin County Health Care Services <br />