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RECEIVED <br /> NOV 2 1 2011 <br /> ' November 10, 2011 <br /> ENVIRONMENTAL HEALTH <br /> PERMIT/SERVICES <br /> ' Ms. Natalia Subbotnikova <br /> San Joaquin County Environmental Health Department <br /> 600 E. Main Street <br /> Stockton, California 95202 <br /> Subject: Transmittal of Well Decommissioning Work Plan <br /> ' World Enterprises,Turnpike Road, Stockton,California <br /> Dear Ms. Subbotnikova: <br /> ' On behalf of Radio Shack Corporation,URS Corporation Americas(URS)has prepared this work plan <br /> describing procedures required to decommission three groundwater monitoring wells(MW-1 through <br /> MW-3)at the World Enterprises site located on Turnpike Road,south of Downey Road, in Stockton, <br /> California(Figure 1). <br /> SITE BACKGROUND <br /> The World Enterprises site is located in Stockton, California. From 1970 through 1978,this site was <br /> operated as a debris disposal site(debris from demolished buildings, including wood, rubble,concrete, <br /> and other fill materials)under San Joaquin Local Health District Use Permits to World Enterprises. <br /> ' On July 17, 2003, during an annual site inspection,the San Joaquin County Environmental Health <br /> Department(SJCEHD)staff measured methane gas concentrations up to 30,000 parts per million by <br /> ' volume(ppmV)(3 percent by volume)along the property boundary. As a result of this inspection, <br /> SJCEHD required Tandy Corporation(site owner, currently known as RadioShack)to assess whether <br /> the methane concentration along the property boundary was greater than 5 percent by volume and, if <br /> found to be greater than 5 percent by volume,to implement measures for controlling methane from <br /> leaving the site. RadioShack contracted with URS to assess the extent of methane at the World <br /> Enterprises site. Since 2004,URS has installed 10 gas-migration monitoring probes, 2 vapor extraction <br /> wells, and 3 groundwater monitoring wells at the World Enterprises site(Figure 2). <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 less than 5 ppmV. Based on these results, VOC constituents could be present in <br /> groundwater. To assess the presence or absence of VOC constituents in the groundwater, three <br /> ' groundwater monitoring wells(MW-1 through MW-3)were installed at the site on June 12, 2006. <br /> Following the installation of groundwater monitoring wells, groundwater samples were collected <br /> quarterly and analyzed for VOCs. Mr. Ross Atkinson(Regional Water Quality Control Board <br /> ' [RWQCB])requested that groundwater samples be collected and analyzed for metals and general <br /> minerals(only total dissolved solids [TDS]after the first event)starting the fourth quarter of 2006 <br /> (4Q06). <br /> URS Corporation <br /> Crown Corporate Center <br /> ' 2870 Gateway Oaks Drive,Suite 150 <br /> Sacramento,CA 95833 <br /> Tel:916.6792000 <br /> Fax:916.679.2900 H:\Wprocess125532\WorldEnterpriselWell Destruction\Report.doc <br />