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SUMMARY OF REMEDIATION ALTERNATIVES <br /> The OU #1 groundwater FS for DDRW-Tracy was presented to EPA in October 1992. <br /> DDRW-Tracy, the Central Valley Regional Water Quality Control Board (RWQCB), <br /> California's Department of Toxic Substances Control (DTSC), and EPA have evaluated four <br /> alternatives for groundwater cleanup at DDRW-Tracy. These four alternatives are discussed <br /> below. <br /> TCE and PCE are the target chemicals of concern to be cleaned up. Other volatile organics <br /> such as 1,1-dichloroethene, carbon tetrachloride, and chloroform will be cleaned up along <br /> with the TCE and PCE. Inorganics) ound at elevated concentrations in the OU #1 plume <br /> such as boron and nitrate nd pesticides)such as dieldrin are no believed to have on-site <br /> sources. However, groundwater extracted for treatment may have to be pre-treated for one <br /> or more of these compoundsio prevent damage to the treatment system and impacts on the <br /> reinjection aquifer groundwater quality. IFprostrtl to wfl;64 1 high Wnces?fhahmis� <br /> Alternative 1, termed "no-action," consists of no physical cleanup, but monitors the <br /> groundwater plume using about 30 existing on-site and off-site monitoring wells. <br /> Consideration of the "no action" remedial alternative is required by the National Oil and <br /> Hazardous Substances Pollution Contingency Plan (NCP). It also serves as a reference for <br /> comparison of the cost and non-cost characteristics of the other remedial alternatives. This <br /> alternative would be implemented for 30 years. The estimated costs are shown below: <br /> Monitoring Costs $1,734,300 <br /> Capital Costs 0 <br /> Annual Operations and Maintenance 0 <br /> (O&M) Costs <br /> Present Worth Cost for 30 years $1,734,300 <br /> "Present-worth cost" is the amount of money that, if invested now, would cover all the <br /> estimated costs of the proposed alternative. <br /> Alternative 2, termed "Institutional Controls," consists of no physical cleanup but prohibits <br /> the drilling of off-site shallow wells downgradient of DDRW-Tracy in the area presently <br /> Q190,7063.1(90390C)\10 10 M1007922139 <br />