(50a) The Fate, Transport and Control of Persistent Organic Chemicals In Sediments

Contaminated sediments represent some of the most difficulty and potentially costly environmental problems. Contaminated sediment sites are typically characterized by large volumes of marginally contaminated sediments that are made more difficult to manage due to poor access and limited treatment options. Effective management requires a solid understanding of the processes giving rise to exposure and risk as well as recognition of available but limited treatment options that exist. This presentation will summarize the unique characteristics of sediment that control the risk associated with contaminants, current research to develop improved assessment approaches and the opportunities and challenges of management options. The presentation will focus on the role and characteristics of the biologically active zone of sediments and the use and measurement of interstitial water concentrations to assess risk and develop conceptual site models. The limitations of dredging as cited by a recent National Research Council report and conventional passive capping will be summarized. Experiences with approaches providing more effective in-situ management and control of contaminant mobility and risk will be identified.