Incorporating sediment stability within the management of contaminated sediment sites: a synthesis approach.
At the Third International Conference on Remediation of Contaminated Sediments, a panel discussion was held to consider how best to incorporate sediment stability assessment (SSA) results when managing risks at contaminated sediment sites. This remains a challenge to the scientific and regulatory community, especially at sites where large volumes of legacy sediment are present below layers of recent sediment of better quality, and where in-place management may be viable. Use of a suite of empirical and predictive approaches collectively to assess potential risks resulting from bed erosion has emerged as the state-of-the-art approach for SSA, yet current practice lacks consistent guidance for conducting such assessments and for dealing with and communicating implications of uncertainty. The regulatory community lacks a decision-making framework that specifically incorporates SSA results, though it is a consideration in US Environmental Protection Agency (USEPA 2002) Principles for Sediment Management. Practitioners have not consistently communicated SSA results from a risk perspective to the stakeholder community. We believe this combination of factors, especially the inconsistent framing of results in a risk context, has contributed to discounted use of sediment stability information in decision making, fostering application of the precautionary principle, where removal is viewed as a presumed conservative but more expensive approach over in-place management options. We assert that the incorporation of SSA in decision making will be improved through the use of a consistent SSA assessment framework built around the conceptual site model, incorporating multiple lines of evidence detailing the potential impacts of large, low-probability events (e.g., the 100-y storm) on exposure and risk, and the associated uncertainties. Further advocacy of this approach was realized through panel-audience discussion at the conference. The technical methods discussed are not new; rather, it is the synthesis approach emphasized here, which by providing a framework for the systematic evaluation of how SSA is best addressed from site to site, makes the results of SSA efforts more accessible and acceptable to stakeholders and decision makers.
Bohlen
W Frank
WF
University of Connecticut, Department of Marine Sciences, Groton, Connecticut 06340, USA. Bohlen@uconn.edu
Erickson
Michael J
MJ
D003247:Conservation of Natural Resources; D003625:Data Collection; D003657:Decision Making; D004777:Environment; D004785:Environmental Pollutants / Q000032:analysis* / Q000506:poisoning*; D019015:Geologic Sediments / Q000737:chemistry*; D008962:Models, Theoretical; D011786:Quality Control; D015203:Reproducibility of Results; D018570:Risk Assessment; D014481:United States; D014484:United States Environmental Protection Agency; D014872:Water Movements
D004785:Environmental Pollutants