Sediment Cleanup—Basin-Scale Risk Assessment Used to Assess Effectiveness of the Current Process and Explore Alternatives

摘要

Background/Objectives. The current process for large-scale sediment cleanup, thetype needed to achieve any significant reduction of ecological and human health risksfrom this stressor, typically takes over 10 years per site, creates large impacts to theecosystem that affect our overall welfare, and provides marginal human health riskreduction. Taking results from individual site assessments and evaluations of remedyimpacts and effectiveness, and applying that to a basin- or region-wide geographicscale risk assessment (in this case Puget Sound), the timing and magnitude ofrisk-reduction can be demonstrated and the improvement to ecosystem services canbe quantified.Approach/Activities. The relative reduction of risks from these stressors can thenbe prioritized against other management actions to address other stressors to improveour ability to maximize improvements to ecosystem services across the region in thetimeliest manner. They can also be used at this scale to assess sustainability andregional impacts of remedial choices. The information is used to identify otherinnovative approaches to sediment cleanup process that could improve on the timingand magnitude of risk reductions at the broader geographic scale.Results/Lessons Learned. By accepting the tenet that there will always beuncertainty in the level of understanding how remedies will respond in thesecomplex systems, a fundamentally different approach to sediment remediation thatis significantly faster becomes possible. The difference in effectiveness can bedemonstrated by basin-scale risk assessment. Under this new approach, otherlarge-scale remedy possibilities that could improve timing or magnitude of riskreduction, while having less impact on overall welfare, are explored.