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� PUBLIC FILALTHNEVI " � � � <br /> S opaUi <br /> SAN JOAQUIN COUNTY -mac <br /> ENVIRONMENTAL HEALTH DIVISION �` I <br /> Karen Furst, M.D., M.P.H., Health Officer <br /> 304 East Weber Avenue, Third Floor • Stockton, CA.9 0 <br /> 2091468-3420 <br /> } <br /> MIKE MCGRANAHAN <br /> LOUISE MORESCO PROPERTY MR0 9 <br /> PO SOX 5018 <br /> MODESTO CA 95352 <br /> RE: iMORESCO PROPERTY SITE CODE: 505486 <br /> 16865 GAWNE ROAD <br /> STOCKTON CA <br /> On December 8, 1997 San Joaquin County Public Health Services Environmental Health Division <br /> (PHS/EHD) received correspondence from your consultant, Geological Technics Inc. (GTI) addressed to <br /> San Joaquin Valley Unified Air Pollution Control District (the Air District) compliance staff dazed <br /> December 4, 1997. PHS/EHD reviewed this correspondence which-reported the results of laboratory <br /> analyses for both air influent and effluent samples from the operating soil vapor extraction system (SVES) <br /> at the above referenced site. PHS/EHD provides the following comments and directives. <br /> PHS/EHD has received and reviewed correspondence from GTI dated January 26, and February 7, 1998 f <br /> and the Remedial Action Report dated February 6, 1998. PHSIEHD will not comment on these documents <br /> recognizing that directives contained in this correspondence may result in significant modifications to the <br /> correspondence and reports generated to date. <br /> The data presented in the above referenced correspondence (December 8, 1997) provided information to <br /> this regulatory agency which indicated that the SVES was not performing at levels expected based upon <br /> reports generated by GTI in the past (See Site Characterization Report by GTI dated October 11, 1996) <br /> which estimated that 1,675 gallons of fuel resided in the treatment area (SVES) at the above referenced <br /> site. The December 4, 1997 correspondence to the Air District reported a calculated air influent <br /> concentration to the SVES at 3.10 ug/1 and effluent concentrations at.0.010 ug/L for benzene which are <br /> unusually low given the reported mass balance. The December 4, 1997 correspondence also stated,"At the <br /> time these samples were collected the extraction system was pulling from the air recharge wells". This <br /> method of operation is not standard or common. Operating the system in this manner creates a potential <br /> for contaminants to be redistributed through the vadose zone away from the core extraction well, <br /> decreasing efficiency. . <br /> PHS/EHD contacted the Air District compliance staff and management to discuss data generated and the <br /> method of SVES operation at this site. As a result of these discussions:the Air District required a retest of <br /> the SUES witnessed by Air District and PHS/EHD staff employing the designated core vapor extraction 4 <br /> well. Although samples were eventually obtained (January 9, 1998), the consultant reported that they i <br /> failed to submit the samples to the laboratory for analyses in time to meet the required 72 hour maximum <br /> hold time_ As a result no quantitative data, collected under regulatory inspection, is available to evaluate <br /> the effectiveness of the SVES at the above referenced site employing the core extraction well although the <br /> system has been operational for approximately three months_ <br /> On several occasions including the January 9, 1998 site inspection PHS/EHD staff commented to GTI staff <br /> on the systems apparent ineffective/poor performance. The consultant was asked to provide comments on <br /> the systems poor performance in a written format recognizing that PID (Photo-ionization Detector) <br /> A Division of San Joaquin County Health Care Services <br />