SITE INFORMATION AND CORRESPONDENCE

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a 0 Draft Final Site-Wide ROD -2- 26 January 1998 DDJC Tracy the CoC's background ground water concentration exceeds the limit, the selected remedy should include the background ground water concentration rather than the limit limit and be clarified in a footnote as such. As we agreed during the 9 January 1998 conference call, in cases where the background concentration is equal to non-detect or less than the USEPA specified method detection limit(MDL), or where the beneficial use limit is less than the MDL, the selected remedy will include the USEPA MDL rather than the beneficial use limit. The ROD should clarify that future ground water monitoring results will include reporting of all concentrations detected above the MDL and below the laboratory reporting limit as trace or flagged estimated concentrations. 2. CoCs Requiring Ground Water Evaluation. The ROD identifies the CoCs to be monitored in ground water as part of each selected remedy. All CoCs which pose a threat to background water quality or to beneficial uses of ground water should be evaluated. Therefore, we request that CoCs be added as follows: Site Coca SWMU 7 2,4-D SWMU 24 Fluoranthene,2-methylnapthalene,4-methylphenol Drum Storage Area- VOCs, pesticides/herbicides Building 30 3. Ground Water Monitoring at SWMU 7. The ROD states that two new ground water monitor wells will be installed as part of the selected remedy for SWMU 7. Section 9.7.3.6 further states that the new wells will be sufficient to assess any ground water contamination eminating from the burn pits without performing additional monitoring of LM095A and LM043A. Based on the locations presented on Figure E-2 of the ROD, the new wells are immediately downgradient of the south area pits. However, these wells are not appropriate for monitoring ground water immediately down gradient of the north area pits. We request that monitoring of well LM095A continue as part of the selected remedy to evaluate ground water in the down gradient vicinity of the north area pits at SWMU 7. Section 9.7.3.6 and Table 9-2 should be modified accordingly. 4. Soil Cleanup Levels. We request that DDJC Tracy revise the cleanup levels for MCPA (5000 ug/kg) in soil at SWMUs 8, 20, and 27 and for 2,4 Dinitrophenol (1300 ug/kg) in soil at SWMU 20. DDJC Tracy proposed an increase from the soil cleanup levels in the RDFS for these CoCs based on analytical methods and achievable reporting limits, as discussed in Appendix F of the ROD. However, the ROD cleanup levels for MCPA and 2,4 Dinitrophenol exceed the estimated concentrations necessary to protect background water quality and beneficial uses of the underlying ground water by at least two orders of magnitude. In addition,Appendix F shows achievable reporting limits for MCPA at 200 ug/kg and a proposed lowest reporting limit for 2,4 Dinitrophenol at 830 ug/kg which are significantly lower than the proposed cleanup levels. As discussed in our 10 October 1997 comments on the Draft ROD, the equilibrium partitioning limits developed in the RI/FS may be considered conservative estimates of concentrations necessary to protect ground water;however,the ROD should justify on a site-specific basis how the proposed soil cleanup levels are adequate to protect water quality.