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than tetrachloroethene (PCE) and trichloroethene (TCE) . <br /> Since this is a public document, it is important that DDRW- <br /> Tracy emphasize throughout this document how the remedial <br /> alternatives being considered will address all the organic <br /> contaminants. <br /> Provide a detailed discussion in the Introduction <br /> explaining how the remedies under consideration will <br /> address all the organic compounds listed in Section <br /> 6. 2 . 4 . 1 of the RI . DLA may want to also explain that <br /> TCE and PCE are the most prevalent and mobile of the <br /> contaminants. <br /> • List all the organic compounds in Section 6. 2 . 4 . 1 of <br /> the RI in the FS. <br /> Whenever TCE and PCE are referenced in the FS, DLA <br /> should also remind the reader that the other organic <br /> compounds are included. <br /> 3 . The first three alternatives presented in Sections 3 (and <br /> those carried into Section 4) do not follow EPA guidance <br /> with respect to "no action" and "institutional controls" and <br /> will require further delineation. Additionally, the <br /> alternatives which are solely dependent upon the operation <br /> of the IRM will not address all of the OU-1 plume and, <br /> therefore, should not be a part of the evaluation. EPA has <br /> suggested a means to address these problems (see comments on <br /> Section 3) . <br /> 4 . The air-stripping process option, which is retained as a <br /> component into the detailed analysis, is susceptible to <br /> clogging when significant amounts of inorganics are present. <br /> This clogging will reduce the efficiency of the air stripper <br /> thereby increasing the total remediation time period and <br /> increasing the potential for contaminant breakthrough. <br /> The draft Proposed Plan for OU-1 references the <br /> possibility of pretreatment of the ground water to <br /> address inorganics. Section 3 . 3 of the FS does not <br /> mention any pretreatment. If pretreatment is to be <br /> considered, it needs to be discussed in the FS. <br /> The potential for metals contamination being present <br /> and the possible need for some form of pretreatment for <br /> metals should be added to the discussions on the air- <br /> stripping alternatives. <br /> 5. As currently written, the FS does not clearly identify which <br /> is the preferred alternative. The FS needs to be modified <br /> to include a concluding section which identifies the <br /> preferred alternative. Further, this concluding section <br /> 2 <br />