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(44-02) Framework for Evaluating the Effectiveness of Monitored Natural Recovery (MNR) as a Contaminated Sediment Management Option. Swindoll, M.*,1, Davis, J.2, Patmont, C.3, Ells, S.4, Stahl, R.5, 1 ExxonMobil Biomedical Sciences, Inc., New Jersey, USA2 The Dow Chemical Company, Midland Michigan, USA3 Anchor, Seattle Washington, USA4 U.S. EPA Office of Emergency and Remedial Response, Washington D.C., USA5 DuPont, Wilmington Delaware, USA ABSTRACT- Monitored Natural Recovery (MNR) of sediments is a risk management alternative that relies upon natural environmental processes to permanently reduce risk to the environment. MNR is appealing as a management alternative for sites where it is appropriate because it allows limited resources to be focused to where they are needed. Although MNR is identified as one possible management option for addressing contaminated sediments, widely-accepted evaluation process is lacking. A process for evaluating MNR at contaminated sediment sites is under developed by the Remediation Technologies Development Forum (RTDF) Sediment workgroup. The process includes steps, such as careful data assessment, modeling, and site monitoring, that are intended to facilitate the decision as to the appropriateness of MNR for a contaminated sediment site. It is envisioned that the RTDF MNR framework will increase the certainty associated with the effectiveness of this remedial option, and thus increase its acceptance when it ca be considered an appropriate alternative for a site. In addition, the framework provides a means to monitor site conditions to ascertain whether risk remains acceptable. The framework identifies conditions and data required for an evaluation of MNR, and identifies approaches and tools that can be used to conduct this evaluation. Data for several sites that have been evaluated using the framework are presented to illustrate its potential utility in support of risk-based decision making. Key words: sediment, natural recovery, risk assessment, remediation |
