SITE INFORMATION AND CORRESPONDENCE

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Site-Wide Comprehensive ROD -8- 1 May 1997 DDRW Tracy evaluated prior to implementing the SVE system as the selected remedy at these sites. All summary tables, if used, should be numbered. 9. Section 6.0: No acknowledgement of the water quality site assessment is present in the summary of site risks. The text should clarify that site risks were evaluated using both a water quality site assessment and a baseline risk assessment. Text should be added to describe how the water quality site assessment was conducted, in some cases followed by a fate and transport analyses, to determine which COCl posed a threat to background groundwater quality and beneficial uses. 10. Section 7.0: This section does not clearly describe the remedial alternatives evaluated. Text appears to re-state the remedial action objectives as presented in the RI/FS Report. This information should be condensed and used in the section which describes how each remedial alternative addresses the principal threats posed by the CoCs at the site. If the ROD is re- organized to include main sections focused on the"groups" of sites. The remedial alternatives should be listed and described in the text of these sections. The information presented in Tables 7-1 through 7-13 is limited with respect to describing the alternatives. These tables should be deleted or modified to show the comparison of the alternatives evaluated with respect to NCP criteria. Section 8.0 (Comparative Analysis of Alternatives) contains more descriptive information which should be used as part of the description of alternatives. 11. Section 9.0 (Selected Remedies): ARARs are incomplete and inadequately described. The text should describe how each remedy complies with ARARs (see general comment #3). The term "potential" should be deleted. The words "at least" should be added to the subsections which discuss the duration of monitoring included as part of the remedy (e.g, CoCs must be monitored anually"at least" four years). Language should be added to clarify that resulting monitoring data will be reviewed to determine if further monitoring is necessary. Further text should specify that any reduction or elimination of monitoring will be determined in accordance with the procedures set forth in the Well Monitoring Program. Each alternative includes a subsection to identify activities which"may affect implementation of the selected remedy." This language is vague with respect to whether or not the selected remedy will somehow be modified. Details of any"potential' modification should be clearly presented, including conditions for making the modification, as part of the selected remedy. In the sub-sections which describe the remedial action objectives, the CoCs should be specified (listed) to clarify exactly what CoCs were identified as a risk to human health and the environment and water quality. Cleanup levels are incomplete and should be presented as a major component of each remedy. In the sub-sections where cleanup levels are identified, the text often refers to "the basis for the soil cleanup levels" as being the practical quantification limit or reporting limit. This text is misleading and should be modified to state that these limits were selected as the cleanup levels which would protect groundwater and meet ARARs and TBCs. In addition, the text should describe in detail how these limits were established. This may help to resolve our concerns that some, particularly for SVOCs and pesticides, appear too high. Each presentation of cost is incomplete because it is limited to providing lists of costs in tables and no text is presented to describe how the selected remedy provides cost-effectiveness.