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identified and set for the remedial action. <br /> Corrective Action: Either identify background values with the concurrence of all <br /> parties to the FFA, or delete the references to background and commit to meet the <br /> numeric effluent standards presented for BAT. <br /> 39. Table 4.2-2, OU #1 Chemicals of Concern Aquifer Cleanup Levels and Preliminary <br /> Effluent Treatment Standards <br /> The footnote to this table indicates that arsenic in groundwater is not known to be <br /> attributable to sources on-Base. However, recent groundwater data (from non-turbid <br /> samples) indicates elevated concentrations of arsenic immediately downgradient of <br /> selected on-Base SWMUs. These data have been graphically presented as plumes. <br /> Corrective Action: Revise the text in the footnote. Further, it would appear that the <br /> ROD needs to establish an effluent standard for arsenic. <br /> 40. Table 4.2-3 <br /> In Table 4.2-3 under the column "Preliminary Effluent Treatment Standard" <br /> ("Preliminary" should be deleted), either 1.0 or background should be the one selected <br /> standard, but not the choice of either one. Without a number for background, the <br /> BAT number will set the standard. Also, under the "Source" column, Resolution 68- <br /> 16 (not background) is the source. <br /> Corrective Action: Select one number as the standard. Modify the source column to <br /> reflect that Resolution 68-16 is the source of the standard. <br /> 41. Section 5.0 <br /> This section of the ROD needs to contain a statement on the quality of the RI <br /> database. <br /> Corrective Action: Add a section to address this requirement. Example text: "All <br /> remedial investigation data have been validated and the quality is acceptable to <br /> support the recommendations of this ROD." <br /> 42. Section 5.1.1 <br /> This section is entitled "Known or Suspected Sources of Contamination" It does not <br /> follow that the text should focus on the areas which are not believed to be sources. <br /> Corrective Action: Delete the text which minimizes the possibility of sources. <br /> Instead, include a clear discussion of the known or suspected sources of <br /> contamination. At a minimum, summarize the basis for the investigations planned in <br /> the Comprehensive RI/FS Work Plan. <br /> EPA/R9 June 7, 1993 11/40 <br />