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kn KLEINFELDER <br /> 1 INTRODUCTION <br /> Forward Landfill, located southeast of Stockton, is currently operating Class H and Class <br /> III Waste Management Units (WMUs). One of the oldest units, WMU A, accepted small <br /> amounts of hazardous waste and has been classified as a Class I unit for the purpose of <br /> closure and post-closure. <br /> WMU A is regulated by the California Department of Health Services (DHS), Toxic <br /> Substances Control Program. In a post-closure permit, DHS has required Forward Landfill <br /> to conduct a RCRA Facility Investigation (RFI) addressing the issue of apparent <br /> contamination in monitoring well 5A (MW-5A). Low levels of metals and volatile organics <br /> have been detected in this well. Relative to the direction of ground water flow, WMU B is <br /> upgradient of WMU A and MW-5A is immediately upgradiant of WMU B. <br /> Kleinfelder has been retained by Forward Inc. to prepare the RFI Workplan and conduct <br /> the RFI investigation. Kleinfelder proposes to conduct the RFI as a five step process: <br /> Environmental Setting Characterization - Data from existing investigations will be <br /> summarized to obtain information on soil characteristics, site geology, ground water <br /> direction and gradients, and ground water chemistry. Slug tests will be conducted to obtain <br /> information on aquifer characteristics. <br /> Source Characterization - Data from existing investigations and records will be summarized <br /> to obtain information on the construction, operation, and waste or chemical content of <br /> WMU B, the old solar evaporation ponds, and the South Fork of South Littlejohns Creek. <br /> In order to assess which of these areas may be responsible for ground water contamination <br /> in the vicinity of MW-5A, vadose zone soil cores will be collected from beneath each of the <br /> three areas. If any of these units are releasing, or have released, contaminants to ground <br /> water, evidence of contamination should be present in the vadose zone. The soil cores will <br /> be tested for soluble constituents using the Toxic Characteristic Leaching Procedure <br /> (TCLP). A boring will also be drilled in the southwest corner of WMU B to assess whether <br /> leachate is present at the soil/waste interface. This information is important to the <br /> C7-90-99 1 <br />