SITE INFORMATION AND CORRESPONDENCE

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REMEDIAL ALTERNATIVES - 5 - 6.0 5 -6.0 Evaluation of Groundwater Alternatives The report is not a true feasibility study for groundwater cleanup. The Basin Plan states that the discharger is to submit a "feasibility study of cleanup alternatives which compare effectiveness, cost, and time to achieve cleanup levels." The report contains only a qualitative discussion of the effectiveness of various cleanup alternatives. In this section of the report, cost is used as a rationale for discarding various alternatives. However, the Basin Plan states that "economic feasibility does not refer to the subjective measurement of the ability of the discharger to pay the costs of cleanup, but rather to the objective balancing of the incremental benefit of attaining more stringent levels of constituents of concern as compared with the incremental cost of achieving those levels." The report does not consider economics in this manner. The report also states that "there is no practical method" for removing 1,2-DCP from the groundwater. However, the report does not contain enough quantitative detail to determine whether this is a true statement. The Basin Plan requires that technologic feasibility be determined by "assessing the availability of technologies which have been shown to be effective in reducing the concentrations of the constituents of concern to the established cleanup levels. Bench-scale and/or pilot-scale studies may be necessary to make this feasibility assessment in the context of constituent, hydrologic, and other site-specific factors." 6.1. 6 2 6.3 Pumping/Hydraulic Containingnt Aquifer tests have not been conducted at this site. Therefore, the discussion of these three alternatives is subjective. Before these alternatives can be discarded, the discharger needs to provide more data regarding the pumping characteristics of the aquifer. 6.4 Air Sparging and Vapor Extraction Air sparging and vapor extraction is being used successfully to remediate a groundwater plume in Yolo County that contains, among other chemicals, 1,2-DCP. The Yolo County site contains 1,2- DCP in similar concentrations to this site. The report's statement that "a specific drawback to air sparging and vapor extraction is the low concentrations of contaminants present" is misleading and apparently inaccurate.