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LD <br /> California Reginal Water Quality Ctrol Board : <br /> Central Valley Region <br /> Robert Schneider,Chair <br /> Winston H.Hickox Gray Davis <br /> Secretaryfor Sacramento Main Office Governor <br /> Environrneatal Internet Address: http://www.swrcb.ca.gov/-rwgcb5 <br /> Protection 3443 Routier Road,Suite A,Sacramento,California 95827-3003 p "^ <br /> Phone(916)255-3000•FAX(916)255-3015 N <br /> CO Ti c <br /> 4 February 2002 O1 <br /> Z _. <br /> Mr. Robert Garcia n <br /> Leprino Foods,Inc. <br /> 1830 West 38th Avenue _ <br /> Denver, CO 80217 <br /> FOURTH QUARTER 2001 GROUNDWATER MONITORING REPORT AND RESPONSE TO <br /> COMMENTS, THIRD AND FOURTH QUARTER SEMIANNUAL GROUNDWATER <br /> MONITORING REPORT, LEPRINO FOODS COMPANY, TRACY, SAN JOAQUIN COUNTY <br /> We have reviewed the Fourth Quarter 2001 Groundwater Monitoring Report (Report) and Response to <br /> Comments, Second and Third Quarter 2001 Semiannual Groundwater Monitoring Report, Leprino <br /> Foods Company, Tracy, San Joaquin County (Letter Response), prepared by GeoTrans,Inc. for Leprino <br /> Foods Company and received 25 January 2002. The Report shows petroleum hydrocarbon levels of <br /> separate phase product (SPP)in monitoring well MW-4, and Total Petroleum Hydrocarbon as Diesel <br /> (TPH-D) concentrations in groundwater at downgradient property line monitoring wells RW-1 and RW- <br /> 2 are now increasing. These increases are possibly as a result of seasonal variations associated with a <br /> rise in the water table and remobilization of petroleum hydrocarbons in a suspected smear zone. The <br /> Report states that dissolved phase hydrocarbons that have migrated to the northern property boundary are <br /> now stable, and that continued groundwater capture and natural attenuation should limit plume <br /> migration. <br /> The Letter Response states that hydraulic containment of the petroleum hydrocarbons plume is adequate, <br /> and that the general site-wide groundwater TPH-d concentration trend continues downward. The Letter <br /> Response suggests that RW-2 lies in a stagnation zone (groundwater capture divide)between extraction <br /> wells RW-4A and RW-5A. The Letter Response concludes that smear zone impacts at RW-1 and RW-2 <br /> will be evaluated for additional remedial recommendations in the semi-annual report (due 30 April <br /> 2002). <br /> The Report requests that, due to declining concentrations, RW-4A be evaluated for shutdown, and that <br /> negotiations begin to define remedial objectives for cessation of treatment system operations. <br /> Comments: <br /> 1. In our letter dated 19 November 2001 (Letter), we questioned whether hydraulic capture was <br /> occurring near the northern property boundary of the site. The Letter stated that if the analytical results <br /> of monitoring two additional quarters show that the contamination levels are rebounding, we would <br /> California Environmental Protection Agency <br /> Qa Recycled Paper <br />