Laserfiche WebLink
EPA Comments on the <br /> Draft Final OU 1 Groundwater: <br /> Interim Remedial Action Report <br /> dated March, 2001 <br /> GENERAL COMMENTS <br /> 1. The Record of Decision (ROD) for DDJC-Sharpe included an operational period of 16 <br /> years to restore groundwater to beneficial use. This Interim Remedial Action Report <br /> (IRAR) cites recent data, including a groundwater modeling effort by the Waterways <br /> Experiment Station, that suggest a cleanup time of 50 years or more. In addition, the <br /> IRAR states that several optimization actions are under consideration, including <br /> aggressive pumping, dynamic underground stripping/hydrous pyrolysis oxidation, and <br /> natural attenuation. The longer cleanup time poses a considerable increase in cleanup <br /> costs over the cost projected in the ROD, and the remedial technologies under <br /> consideration represent potentially significant or fundamental changes in strategy from <br /> the pump-and-treat system currently implemented as the selected remedy. The U.S. EPA <br /> ROD guidance (A Guide to Preparing Superfund Proposed Plans, Records of Decision, <br /> and Other Remedy Selection Decision Documents, EPA 540-R-98-031, July 1999) states <br /> that significant changes may require an Explanation of Significant Difference and <br /> fundamental changes may require a ROD Amendment, depending on the degree of post- <br /> ROD remedy changes selected for the DDJC-Sharpe site. <br /> SPECIFIC COMMENTS <br /> 2. Section 2.2.2, page 2-2: The second and third bullets discuss alternate pumping and <br /> pulse pumping of extraction wells as optimization actions specified in the ROD selected <br /> remedy. It is not clear from the IRAR whether these strategies have been employed at the <br /> DDJC-Sharpe site. Please clarify whether the optimization strategies specified in the <br /> ROD have been implemented and, if not, discuss why not. <br /> 3. Section 5.4, pages 5-3 and 5-4: The text cites the 1998 Version 2.0 of the DDJC- <br /> Sharpe/Tracy Comprehensive Field Work Plan in subsection 5.4.1 and Volume H <br /> (Quality Assurance Project Plan) of the Comprehensive Field Work Plan in subsection <br /> 1 <br />