Sediment Dredging at Superfund Megasites

Some of the nation's estuaries, lakes and other water bodies contain contaminated sediments that can adversely affect fish and wildlife and may then find their way into people's diets. Dredging is one of the few options available for attempting to clean up contaminated sediments, but it can uncover and re-suspend buried contaminants, creating additional exposures for wildlife and people. At the request of Congress, EPA asked the National Research Council (NRC) to evaluate dredging as a cleanup technique. The book finds that, based on a review of available evidence, dredging's ability to decrease environmental and health risks is still an open question. Analysis of pre-dredging and post-dredging at about 20 sites found a wide range of outcomes in terms of surface sediment concentrations of contaminants: some sites showed increases, some no change, and some decreases in concentrations. Evaluating the potential long-term benefits of dredging will require that the U.S. Environmental Protection Agency step up monitoring activities before, during and after individual cleanups to determine whether it is working there and what combinations of techniques are most effective. Table of Contents Front Matter Summary 1 Introduction 2 Sediment Management at Superfund Megasites 3 Effectiveness of Environmental Dredging in Reducing Risk: Framework for Evaluation 4 Evaluation of Dredging Effectiveness: What Has Experience Taught Us? 5 Monitoring for Effectiveness: Current Practices and Proposed Improvements 6 Dredging at Superfund Megasites: Improving Future Decision-Making Appendix A: Statement of Task for the Committee on Sediment Dredging at Superfund Megasites Appendix B: Biographic Information on the Committee on Sediment Dredging at Superfund Megasites Appendix C: Summary of Remedial Action Objectives, Cleanup Levels (Numerical Remedial Goals), and Their Achievement at Sediment-Dredging Sites