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41ECEIVE <br /> EB 072014 D <br /> January 23,2014 <br /> "P�MM ENTAL t�LT" <br /> Mr.Robert McClellon <br /> Supervisor R.E.H.S. <br /> San Joaquin County Environmental Health Department <br /> 304 East Weber Avenue,Third Floor <br /> Stockton,California 95202-2708 <br /> Subject: Annual Monitoring Report <br /> World Enterprises Site <br /> Stockton,California <br /> Dear Mr. McClellon: <br /> URS Corporation Americas(URS)has prepared this letter report on behalf of RadioShack. This report <br /> provides a description of the monitoring activities completed at the World Enterprises site in Stockton, <br /> California(Figure 1),during the fourth quarter of 2013 (4Q13)and summarizes the results of these <br /> monitoring activities.This report is organized in the following four sections: Background,Field <br /> Activities,Results,and Conclusions and Recommendations. <br /> BACKGROUND <br /> The World Enterprises site is located in Stockton,California. From 1970 to 1978,this site operated as a <br /> debris disposal site(debris from demolished buildings,including wood,rubble,concrete,and other fill <br /> materials)under San Joaquin Local Health District Use Permits to World Enterprises. On July 17,2003, <br /> during an annual site inspection,the San Joaquin County Environmental Health Department(SJCEHD) <br /> staff measured methane gas concentrations up to 30,000 parts per million by volume(ppmV)Q percent <br /> [%]by volume)along the property boundary.As a result of this inspection, SJCEHD required Tandy <br /> Corporation(site owner,currently known as RadioShack)to assess whether the methane concentration <br /> along the property boundary was greater than 5%by volume,and if found to be greater than 5%by <br /> volume,implement measures for controlling methane from leaving the site. RadioShack contracted with <br /> URS to assess the extent of methane at the World Enterprises site. Since 2004,URS has installed 10 gas <br /> migration monitoring probes,2 vapor extraction wells,and 3 groundwater monitoring wells at the World <br /> Enterprises site(Figure 1). <br /> As a result of the field investigations,methane concentrations along a portion of the property boundary <br /> were found to be above 5%by volume. In September 2006,a passive soil vapor extraction trench was <br /> installed to control methane from leaving the site. <br /> In December 2005,a vapor extraction pilot test was conducted to evaluate the feasibility of installing a <br /> permanent landfill gas extraction system.During this test,vapor samples were collected from the two <br /> extraction wells and analyzed for volatile organic compounds(VOCs). Analytical results of these <br /> samples confirmed the presence of VOCs where the total VOC concentration in each of the vapor <br /> extraction wells was below 5 ppmV. Based on these results,VOC constituents could be present in <br /> groundwater.To assess the presence or absence of VOC constituents in groundwater,three groundwater <br /> URS Corporation <br /> Crown Corporate Center <br /> 2870 Gateway Oaks Drive,Suite 150 <br /> Sacramento,CA 95833 <br /> Tel:916.679.2000 <br /> Fax:916.679.2900 H:\Wprocess\25532\WoddEnlerprise\Quartedy Rpt\2013\TeM.doc <br />