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GeoHydrologic Consultants, Inc.
<br /> 4.0 CONCLUSIONS AND RECOMMENDATIONS
<br /> In December 2007, GHC and Tafoya, on behalf of Thrifty, performed removal of three
<br /> 12,000-gallon USTs, fuel lines,and three dispenser islands,well abandonment, soil
<br /> sampling beneath the USTs and dispensers, replacement well installation, and
<br /> reconfiguration of conveyance piping. On December 10,2007 Tafoya performed the UST
<br /> removal activities of the three 12,000-gallon USTs under authorization of Stockton Fire
<br /> Department and SJCEHD UST removal permits. Health Inspector Ray Von Flue and
<br /> Michael Infurna of SJCEHD were present onsite during the tank removal process and
<br /> approved the tanks and piping for offsite transport and disposal. Soil sample results for
<br /> the samples collected from beneath the gasoline USTs,fuel lines, and dispensers did not
<br /> contain detectable concentrations of any of the analytes of concern. Based on these
<br /> results, it does not appear than any impacts remain in the shallow soils at the Site where
<br /> these samples were collected and no further action is recommended with respect to the
<br /> UST, fuel line, and dispenser removal activities. Thrifty respectfully requests closure for
<br /> these removal activities.
<br /> On February 7 and 8, 2008,GHC oversaw the reinstallation of replacement wells MW-
<br /> 11, MW-12, and VW-3. Tafoya subsequently performed reconnection of these wells and
<br /> several additional existing wells above ground to the existing remediation system on
<br /> April 5,2008. On behalf of Thrifty, GHC has recently submittal the Workplan for
<br /> Remediation System Modification to the SJCEHD, dated April 8, 2008 to address
<br /> required,system modifications to continue the ongoing remediation of deeper petroleum
<br /> affected soil and groundwater at the Site as a result of changes in the City of Stockton
<br /> discharge limits for treated groundwater. Once approval of the workplan is obtained from
<br /> SJCEHD,the proposed system modifications will be implemented and the groundwater
<br /> remediation system will be restarted.
<br /> 5.0 REFERENCES
<br /> Thrifty Oil Company, September 18, 1998. Corrective Action Plan,Thrifty Oil Station
<br /> #172, 7647 Pacific Avenue, Stockton,California.
<br /> The Park Corporation,August 18, 1999.Additional Site Assessment and Remedial System
<br /> Design, Thrifty Oil Station#172, 7647 Pacific Avenue, Stockton, California.
<br /> Thrifty Oil Company,November 10, 1999.Information Requested for Additional Site
<br /> Assessment and Remedial System Design,Thrifty Oil Station #172, 7647 Pacific Avenue,
<br /> Stockton, California.
<br /> Thrifty Oil Company,January 13, 2006.Fourth Quarter 2005 Status Report. Thrifty Oil
<br /> Station#172, 7647 Pacific Avenue, Stockton,California.
<br /> Thrifty Oil Company, February 9,2006.Monthly Groundwater Discharge Report—
<br /> January 2006 Thrifty Oil Station#172,7647 Pacific Avenue, Stockton, California.
<br /> TOC 172 UST Removal Report Final Page 13
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