The Utilization and Effectiveness of Sediment Recontamination Prevention Measures at Superfund Sites: The Lower Duwamish River Waterway Early Action Area Terminal 117, Seattle, Washington

Abstract

Large aquatic Superfund sites often have sediment recontamination issues due to difficulties with pollutant source control, dynamic natural environments and shortfalls in the regulatory systems. The Lower Duwamish Waterway in Seattle, Washington is an example of a large estuarine Superfund site where clean up actions have occurred and more are proposed and potential recontamination threatens the permanence of proposed remedies. Contaminants threaten human and environmental health and recontamination and recontamination prevention can cost millions of dollars, most of which must come from public agencies. Terminal 117, located in the Lower Duwamish Waterway, is selected as a case study to identify regulatory and other issues contributing to recontamination. The objective of this study is to examine two questions: Is recontamination likely to occur at the Lower Duwamish Waterway Terminal 117 site? If so, why are source control efforts not able to prevent recontamination? To assess whether recontamination is likely to occur at the T-117 site this thesis looks at what guidance and laws are available to help prevent recontamination, then reviews the T-117 pollution source control plans and actual source control actions to assesses whether the guidance is being followed. In addition to a literature and technical document review, a dozen professionals working on the LDW Superfund site were interviewed, including federal, state and local agency representatives, citizen group representatives and private sector lawyers and consultants. Research indicated that recontamination is likely to occur at the T-117 site. Potential recontamination may be attributed to technological limitations, environmental and political complexities and failing to identify and/or control pollution sources. To reduce the occurrence of potential recontamination this assessment recommends mandating knowledge sharing for project managers, creating more effective federal guidance on source control methods, and reexamining the achievability of cleanup standards.