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HA1 Contaminated Harbour and River Sediment
() Accumulation of PCBs and Dioxins in New York-New Jersey Harbor.
Farley, K1, 2, Wands, J2, Miller, R2, 1 Manhattan College, Riverdale, NY, USA2 HydroQual, Inc., Mahwah, NJ, USA
ABSTRACT- The accumulation of PCBs and dioxins in New York-New Jersey Harbor is a pressing concern due to fish consumption advisories and restrictions on dredged material disposal. A large field data collection program and mass balance modeling study are currently being performed under the Contaminant Assessment Reduction Project (CARP) to evaluate problems of harbor contamination. As part of this effort, we are conducting modeling studies to explore the roles of estuarine circulation, sediment transport, and organic carbon cycling on the fate and transport of PCBs and dioxins in the harbor region. Results of our modeling studies will be presented to show that tidal and density-driven circulation patterns play a key role in transporting particle-bound contaminants such as PCBs and dioxins. These circulation patterns, combined with salinity-induced coagulation of fine particles and tidally-induced resuspension of sediment, result in downstream transport of large quantities of fine sediment (and sediment-bound contaminants) to the harbor during the spring freshet and other high flow events. These sediments are largely deposited in the harbor region, are subsequently reworked by tidal resuspension and settling, and are transported primarily in the landward direction by density-driven flows. This results in the trapping of significant quantities of PCBs and dioxins in harbor sediment, in spreading contaminants over large areas of the harbor, and in maintaining a close link between contamination in sediments, overlying water, and fish. Finally, increased concentrations of algal and detrital organic matter in the harbor, which is largely associated with sewage discharges from the New York metropolitan area, enhance the trapping of contaminants in the harbor by scavenging dissolved PCBs and dioxins from the water column.
Key words: dioxins, PCBs, sediment contamination, New York-New Jersey Harbor
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