Laserfiche WebLink
ATTACHMENT II <br /> EPA COMMENTS ON THE DRAFT COMPREHENSIVE RI <br /> (RISK ASSESSMENT) WORK PLAN (JAN-92) <br /> FOR DDRW-TRACY <br /> GENERAL COMMENTS <br /> The risk assessment work plan for the DDRW-Tracy site provides <br /> general descriptions of both the risk assessment objectives and <br /> methodology for achieving those objectives. However, specific <br /> details on the methodology, especially for identifying and <br /> evaluating exposure pathways, are not provided. Neither is an <br /> adequate description of integration of the site characterization <br /> data and remedial investigation data provided. <br /> Instead, the work plan focuses on the future generation of a <br /> detailed risk assessment plan, and how conceptual site models <br /> will be developed as one of the first steps of the detailed plan <br /> after first phase of remedial investigation has been completed. <br /> One conceptual site model will be developed for each identified <br /> source type. These conceptual site models will provide the <br /> details on sources, release mechanisms, exposure pathways, <br /> exposure media, and receptors. These items are not identified in <br /> the current work plan. <br /> Since the present work plan only describes how the detailed risk <br /> assessment plan will be developed, rather than presenting the <br /> detailed plan, much of the methodology that would be used for the <br /> risk assessment cannot be evaluated at this time. <br /> The generic approach described in this Work Plan does not satisfy <br /> DDRW-Tracy' s commitment in the FFA. <br /> SPECIFIC COMMENTS <br /> 1. Page 4-1, Section 4 . 0. 0 <br /> The stated objective of the baseline risk assessment should <br /> also include future potential risks as well as current <br /> risks. <br /> 2 . Page 4-1, Section 4 . 0. 0 <br /> It should be clarified that the baseline risk assessment can <br /> take place alongside the remedial investigation and <br /> feasibility study rather than separately and sequentially <br /> between them. Despite the possible concurrent performance <br /> of the risk assessment with the RI and FS, the work plan <br /> should recognize that information from the RI is used in the <br /> risk assessment and that information from the risk <br /> assessment feeds into the FS, as directed under CERCLA <br /> II-1 <br />