APPROACHES USED FOR REMEDY SELECTION AT CONTAMINATED SEDIMENT SITES

摘要

This paper briefly reviews the complex issues associated with remedy identification, screening, and selection at contaminated sediment sites in North America. We present two case studies illustrating approaches used by stakeholders to arrive at remedy decisions. These approaches include watershed-level thinking and net environmental benefit analysis (NEBA), both of which recognize the influences of chemical and non-chemical, natural and anthropogenic stressors, and their respective influences on the integrity of the aquatic ecosystem. In the absence of a sitewide human health or ecological risk assessment, and in the absence of a watershed-level approach that balances potential risks and benefits against implementation risks to human health and the environment, site managers typically are ill-equipped to effectively select environmentally appropriate and protective remedies for contaminated sediment sites. The U.S. Environmental Protection Agency (USEPA) Superfund feasibility study process, and a variety of innovative multi-criteria decision frameworks provide sound frameworks for remedy assessment and selection. Omitting these approaches can result in the selection of a remedy in which the environmental harm caused by the remedy can outweigh its perceived benefits. Two case studies are presented that involve distinct, but mutually supporting, approaches to remedy decision making that reflect unique outcomes in terms of the goals of ecological and human health risk reduction, environmental protection, and watershed improvement. Combined, these case studies evaluate a range of stressors and compare net environmental benefits of each remedy alternative. Outcomes include meaningful risk reductions and minimal adverse impacts to the environment, workers and the local community residents.