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P • • <br /> EPA Comments on the <br /> Draft DDJC-Tracy Remedial Action Report <br /> for SWMUs 2,3, and 33 <br /> November 2001 <br /> GENERAL COMMENTS <br /> 1. The document does not provide adequate documentation to justify why the clean up <br /> standard for the sum of the concentrations of DDD, DDE, and DDT (DDX), established <br /> by the Record of Decision (ROD) and used to complete the initial remedial action, has <br /> now been deleted. The rationale provided indicates the Explanation of Significant <br /> Differences (ESD) was needed since the exposure assumptions used to derive the original <br /> clean up standard were too conservative. It is recognized that the recalculation of risk in <br /> the ESD determined that risks were "biologically insignificant" based on the new <br /> exposure assumptions, thus it can be assumed that a clean up standard would not be <br /> necessary. However, there is currently no rationale provided to suggest why the original <br /> clean up level could not be attained by the remedial action. As indicated in the Specific <br /> Comments, the document has not clearly documented that the receptor and exposure <br /> assumptions used for the recalculation is representative of typical exposures for <br /> vermivore receptors at the site. This should be clarified especially in light of the deletion <br /> of the clean up standard for persistent, bioaccumulative, and toxic chemicals such as <br /> DDX. <br /> 2. This document does not completely follow the current United States Environmental <br /> Protection Agency (EPA) guidance document Close Out Procedures for National <br /> Priorities List Sites," EPA 540-R-98-016, January 2000 (Guidance). It appears that five <br /> required sections for a removal action report are missing or incomplete in this document. <br /> Based on the guidance document, Section VIII is missing information and there are four <br /> missing sections include Section V, Performance Standards and Construction Quality <br /> Control, Section IX, Observations and Lessons Learned, Section X, Operable Unit <br /> Contact Information, and Appendix A, Cost and Performance Summary. Please include <br /> these sections in the draft final version of this report. Alternatively,please explain why <br /> these sections were not included. <br /> 1 <br />