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D �-PTME <br /> ETI <br /> ENVIRON IN COUNTY Unit Supervisors S. <br /> uiy SAN JOAQV Carl Borgman,R.E.H <br /> �o►a ` .a'-.A Third Floor <br /> 304 East Weber Avenue, MikeHuggi ; ikon, S.,R.W.i Donna K.Hersh,RE.H.S. R.E.H.S. <br /> r.`.a> '� y-` °�-' California 95202-2708 Douglas W.Wilson, <br /> < Director Stockton, Margaret Lagorio,R.E.H.S. <br /> A!pin,R.E.H.S. (209}46&3420 Robert McClellon,R.E.H.S. <br /> program Manager Telephone: <br /> Fax: <br /> Program <br /> (209) 164-0138 Mark Barcellos,R.E.H.S. <br /> LiFa Laurie A.COW*R.E.H,SFax <br /> Program Manager FEB 18 2003 <br /> KULJIT MANGAT <br /> DOUG STIDEAM 622 CLAY NAY <br /> CITY OF ESCALON RIPON CA 95366 <br /> Po BOX 248 <br /> ESCALON CA 95320 <br /> RE: South County Food & Fuel <br /> SITE CODE: 1487 <br /> 1305 Escalon Ave <br /> Escalon CA 95320 <br /> San Joaquin County Environmental Health Department (SJCIEHD) has reviewed the <br /> "Report-Vapor Extraction Treatment System Monitoring" dated January 21, 2003 that <br /> was submitted on your behalf by Geological Technics Inc. (GTI)and has the following <br /> comments. <br /> The report summarizes the soil vapor extraction (SVE) remediation that began <br /> operation at this site in February 2002. The system has been in operation for a total of <br /> approximately 230 days and has removed an estimated 675 gallons of gasoline from <br /> the subsurface. For most of the time of operation, vapor has been extracted from <br /> VEW-4. The report concludes that the system has reached it's potential for practical <br /> recovery of hydrocarbons and recommends site closure. <br /> The approximately 675 gallons of gasoline removed from the subsurface at this site is <br /> less than half the contaminant mass estimated to be present prior to remediation, The <br /> report states that the system is currently removing five to seven pounds of <br /> hydrocarbons per day. While this quantity is less than was being removed in the early <br /> months of operation of the system, it is still a significant quantity and SJCIEHD <br /> considers continued remediation to be justified. Daring the SVE pilot test influent vapor <br /> concentrations from the four vapor wells ranged from a low of 17,000 micrograms per <br /> liter(µg11)total petroleum hydrocarbons as gasoline (TPHg)to a high of 54,000 µg11 <br /> TPHg. In the approved "Corrective Action Plan, Revised" (CAP) dated February 26, <br /> 200, GTI stated that"all four wells will be used to cycle the applied vacuum throughout <br /> the affected soils". SJCIEHD requests that this approved proposal be implemented, <br /> that is, apply the vacuum extraction to the lower screened zones. With an estimated <br /> 900 gallons of TPHg remaining in the predominately sandy soil, the groundwater <br /> remains at risk. If contaminant concentrations in the extracted vapors remain low, GTI <br /> may wish to consider switching methods of contaminant destruction. Carbon canisters <br /> may be more cost effective at this point in the process of remediation. <br />