SITE INFORMATION AND CORRESPONDENCE

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Site-Wide Comprehensive ROD -12- 1 May 1997 DDRW Tracy 9. SWMU 30 - Salvage Area. The ROD should clarify that soils have been impacted by SVOCs and that VOCs have been detected in groundwater both downgradient and upgradient of this site. The ROD should explain why SWMU 30 is considered a former source area for VOCs. The site characterization summary should show detections of VOCs (PCE and TCE) in LM119A and LM019A. The upgradient monitoring well LM19A has detected PCE concentrations of 0.54 ug/L, but the downgradient monitoring wells have reported concentrations of PCE which ranged from 1.8 to 3 ug/1 for LM I I9 and from 5.4 to 15 ug/L for LM035A. The site characterization for Building 22 should also show how groundwater data indicates detection of both TCE and PCE in groundwater monitoring wells LM082 A and LM035 which, DDRW Tracy has attributed to SWMU 8. The ROD should clarify how the selected remedy for SWMU 8, which is in close proximity and upgradient of these sites, will address the source area contamination for groundwater contamination observed in wells at both of these sites. 10. Drum Storage Area B30. The ROD should clarify that groundwater data was not available as a basis for the selected remedy. Institutional controls is not a no action alternative; therefore the cleanup levels presented in Section 8 (Table 8-8) of the RI/FS Report must be included as part of the selected remedy for this site. The ROD should state that the selected remedy will include re- evaluating the remedial alternatives to consider active remedial action if and when ground water monitoring (also included as part of the selected remedy) indicates an impact from CoCs present in soil at the site(specific "trigger" language should be presented) . 11. Group C Sites (SWMUs 2, 3, & 33). The list of cleanup levels specified for these sites in Sections 9.6.1.1 & 9.6.2.1 is not complete. The ROD should specify all cleanup levels listed in Table 8-15 and 8-16 of the RDFS Report. The relatively"high" cleanup levels selected from PQLs should be re-evaluated and supported (see specific comment Section 9.0). In addition, the selected remedy for SWMU 33 should include cleanup levels for Bis(2-ethylhexyl)pthalate, ethylbenzene, DDD, DDT, and DDE. The site characterization for SWMU 33 should state that this site is considered a source for VOC and pesticide contamination in groundwater and not, as discussed in Section 5.2, a past source area. Sections 9.6.1.3 & 9.6.2.3 dismiss the alternative of excavating"all remaining soils with constituent levels above FS cleanup levels" for disposal based on technical and economic infeasibility. Sections 9.6.1.4 & 9.6.2.4 present institutional controls as part of the selected remedies to address soils remaining in place after completion of the planned removal actions for SWMUs 2, 3, & 33. This is not acceptable because DDRW Tracy has not conducted the planned removal actions necessary to complete characterization of the nature and extent of soil contamination at SWMUs 2, 3, & 33. Furthermore, during past RPM meetings, particularly the meeting on 17 March 1997 held to discuss the design objectives of these planned removal actions, DDRW Tracy has stated that the planned removal actions are designed to excavate soil beyond the target concentrations to achieve the final cleanup levels based on DLA funding available during the period the excavations are being conducted. DDRW Tracy has further stated that the ability to reach these final cleanup levels will