Toxic Contaminants in the Chesapeake Bay and its Watershed: Extent and Severity of Occurrence and Potential Biological Effects

PCBs are a group of synthetic organochlorine chemicals widely used as dielectric and coolant fluids in transformers and capacitors. In 1977, the U.S. banned the production of PCBs out of concern for their persistence in the environment as well as evidence indicating that PCBs were bioaccumulative and has the potential to cause toxic impacts. Though PCBs are no longer produced, there are continued authorized uses of PCB-containing materials which pose the potential for environmental release. The inadvertent production of PCBs in certain manufacturing processes represents an additional contemporary source. Impairments resulting from PCB contamination are widespread. The Commonwealth of Virginia documents water column impairments in the Potomac and Shenandoah Rivers impacting nine river miles and one square mile of estuarine waters. All of the Bay jurisdictions have waterbodies identified as impaired for human consumption of fish tissue. The District of Columbia and the State of New York have general fish consumption advisories out of concern for contamination of fish tissue from PCBs and other chemical contaminants. The State of New York includes a fish tissue impairment for Koppers Pond, located in the Chemung River basin. Delaware identifies a fish tissue impairment for the Chesapeake and Delaware Canal (C&D Canal). Maryland lists 30 assessment segments as impaired for fish tissue consumption. In Pennsylvania, the Susquehanna River is impaired for 208 river miles, extending from the New York/Pennsylvania state line to the city of Sunbury, PA. Virginia lists five Bay tributaries as impaired, impacting 456 river miles and 2,011 square miles of estuarine waters. In West Virginia, two waterbodies are impaired by PCB contamination in fish tissue: the South Branch of the Potomac River and the Shenandoah River. Unlike concentrations of chlorinated pesticides, concentrations of PCBs in tissues of many species of Chesapeake Bay wildlife have