Public awareness of polychlorinated biphenyl (PCB) contamination in the Hudson River dates back to the early 1970s when elevated levels of the contaminant were discovered in river sediments and fish. This contamination was largely attributed to two General Electric (GE) capacitor manufacturing plants that were operated along the Upper Hudson River approximately 65 km (40 mi) north of Albany, New York. Although highest concentrations of PCBs were reported just downstream of the GE facilities, contamination extended well beyond this section of the river, into the tidal fresh and es-tuarine waters of the Lower Hudson, and down into NewYork Harbor.

Althoughproduction of PCBs in the United States was banned in 1977, contamination of the Lower Hudson remains a serious concern to this day. This is due to the slow breakdown of PCBs in the environment and the long residence times of PCBs in river and fish. In addition, PCBs continue to enter the Lower Hudson from the Upper Hudson as well as from downstream sources (including wastewater treatment plants and combined sewer overflows in the NewYork metropolitan area, and the atmosphere). Understanding how levels of PCB contamination in the Lower Hudson will change in time centers on the following questions:

1. How are PCBs transported through the Lower Hudson River?

2. What processes control the fate of PCBs in the Lower Hudson River?

3. How are PCBs transferred through the Lower Hudson food chain and accumulated in higher predatory fish such as striped bass?

We explored these questions using a mass balance model for PCBs in the Lower Hudson. A description of our modeling approach is first presented. Model results are then compared to observed PCB concentrations in sediments and fish, and are used to examine the critical processes affecting the transport, fate, and bioaccumulation of PCBs in the Lower Hudson.

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