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Linda S. Adams
<br />Secretary for
<br />Environmental
<br />Protection
<br />6 April 2010
<br />California Regional Water Quality Control Board
<br />Central Valley Region
<br />Katherine Hart, Chair
<br />11020 Sun Center Drive #200, Rancho Cordova, California 95670-6114
<br />Phone (916) 464-3291 • FAX (916) 464-4645
<br />http://www.waterboards.ca.gov/centralvalley
<br />Ms. Jennifer Sedlachek
<br />ExxonMobil Environmental Services Company
<br />4096 Piedmont Ave, #194
<br />Oakland, CA 94611
<br />DOCUMENT REVIEW, FORMER MOBIL STATION 99CAS (AKA MARLER PROPERTY,
<br />AKA JH GRIFFIN MOBIL SERVICE), 75 EAST ALPINE AVENUE, STOCKTON,
<br />SAN JOAQUIN COUNTY (CASE # 390857)
<br />(-R 3:`
<br />Arnold
<br />Schwarzenegger
<br />Governor
<br />I reviewed the Corrective Action Plan (CAP), received 29 March 2010 from your consultant ETIC
<br />Engineering, Inc. (ETIC). The CAP evaluated four remedial alternatives in a feasibility study for
<br />reduction of toxicity, plume mobility, and volume of contaminants; technical feasibility; and cost.
<br />The CAP states monitored natural attenuation, while the most cost effective, would not prevent
<br />downgradient plume migration, would not address contaminant mass reduction, and would require the
<br />most time to complete. Groundwater pump and treat would be effective based on hydraulic
<br />conductivity, but would not address soil contamination in unsaturated and vadose zones. Soil vapor
<br />extraction (SVE) would be effective for mass reduction in unsaturated soil, but would not address
<br />groundwater contamination or plume mobility. Dual phase extraction (DPE), for soil vapor, shallow
<br />groundwater and liquid phase hydrocarbons (if present), in conjunction with SVE, would be effective for
<br />soil and groundwater, and is the recommended remedial alternative. The proposed DPE/SVE (cc -
<br />extraction) system would use existing vapor extraction wells (VEW-1 through VEW-4) for soil only SVE
<br />and apply a high vacuum by means of a stinger to the existing groundwater extraction wells (EX -1 and
<br />EX -2), to lower the water table and expose petroleum hydrocarbons to vapor and water/liquid phase
<br />hydrocarbons extraction. Project tasks to be completed upon Regional Board approval include design,
<br />permitting, installation, and operations and maintenance of a co -extraction system.
<br />The CAP recommendation for the co -extraction treatment system is approved. Please provide a work
<br />plan containing the proposed treatment system design elements (plans and specifications, operations
<br />and maintenance manual), and a schedule for the installation and startup of the co -extraction treatment
<br />system by 20 May 2010. If you have any questions, you may contact me at (916) 464-4615, or by
<br />email at jbarton@waterboards.ca.gov.
<br />/s/ original signed by
<br />JAMES L. L. BARTON, P.G.
<br />Engineering Geologist
<br />cc: Ms. Carmen Harms, SWRCB, UST Cleanup Fund, OSCA Account, Sacramento
<br />Mr. Nuel Henderson, San Joaquin County Environmental Health Department, Stockton
<br />Mr. Duane and Ms. Wendy Berdt, Guido Segarini Trust, PO Box 1810, Aptos 95001
<br />Ms. Theresa Marler, 14245 Lora Drive, #16, Los Gatos, CA 95030
<br />Mr. Erik Appel, ETIC Engineering, 2285 Morello Avenue, Pleasant Hill 94523
<br />California Environmental Protection Agency
<br />ca Recycled Paper
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