Impact/Purpose:

The purpose of this research is to provide decision makers at contaminated sediment sites with information about the potential impact of contaminant resuspension. The research is guided by the Office of Research and Developments (ORDs) multi-year plan for contaminated sites research. One of four long term goals of this plan is focused on improving the scientific basis for remedy selection and management at contaminated sediments Superfund sites. The science activity described here constitutes a portion of the ORD program designed to resolve the critical ecological effects science issues necessary for ORD to achieve its contaminated sediments long term goal (By 2008, improve the range and scientific foundation for contaminated sediment remedy selection options, by improving risk characterization, site characterization and increasing understanding of different remedial options).

Description:

At contaminated sediment sites, the Superfund program usually must decide whether to leave the site alone, cap it, or dredge it. This decision is based in part upon the relative risk to the environment and human health posed by each option. Resuspension of contaminants from the sediment to the water column can occur as a result of dredging, or as a result of other events such as ship traffic and storms. Regardless of cause, resuspension may have an impact on risk calculations, potentially by altering bioavailability of the contaminants. Decisions at these sites will be better informed if the likely magnitude and impact of resuspension can be predicted and/or measured. This science activity describes research performed by ORD's National Health and Environmental Effects Research Laboratory (NHEERL). Three tasks are ongoing: (1) fate and transport models are being evaluated for their ability to predict bioavailability of organic and metal contaminants in Superfund site sediments following resuspension events; (2) method development for measuring dissolved organic and inorganic contaminants released under field conditions; and (3) assessing the changes in bioavailability resulting from resuspension and resettlement at contaminated sediment Superfund sites. Contaminated sediment sites are often contentious, in part because dredging, the treatment most often chosen, is costly and in part because the responsible parties have expressed concern that the dredging itself may lead to problems (through resuspension). Results of this science activity will help address resuspension concerns and should lead to less contentious decisions at contaminated sediment Superfund sites.

Record Details: