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DELAWARE ESTUARY PCB MODEL
Impact/Purpose:
The Delaware River Basin Commission will use this research product to develop and implement Total Maximum Daily Loads (TMDLs) for total PCBs for the Delaware Estuary.
Description:
The Delaware River Basin Commission recently completed the first phase of a program to develop and implement Total Maximum Daily Loads (TMDLs) for toxic pollutants for the Delaware Estuary. This complex body of water extends from the head of tide at Trenton, NJ (River Mile 133.2) to the head of Delaware Bay at Liston Point (RM 48.2). Designated uses of the include primary and secondary contact recreation, maintenance and propagation of resident fish and aquatic life, wildlife and drinking water. Water quality problems in the estuary related to toxic pollutants have been documented, and fish consumption advisories issued by the states of Delaware, New Jersey and Pennsylvania are still in effect. Polychlorinated biphenyls (PCBs) are the primary toxic pollutant of concern since this class of compounds forms the basis for many of the advisories currently in place in the estuary. This study will contribute to a larger effort to establish TMDLs for total PCBs for the Delaware Estuary by September 2003 as required by court orders or Memorandums of Agreement between the U.S. Environmental Protection Agency and the states bordering the estuary. Specifically this grant will build upon the hydrodynamic and water quality modeling efforts completed under the Estuary Toxics Management Program by developing a hydrodynamic, sediment and water quality model for PCBs that can be used to apportion the TMDLs. While the Commission currently has a far-field hydrodynamic and water quality model of the estuary that has been calibrated and validated for volatile organic compounds and chronic toxicity, it does not have a water quality model for PCBs, nor does the hydrodynamic model extend to the mouth of Delaware Bay. One critical component of a water quality model for PCBs is the interaction of PCBs with suspended and bottom sediments. Such sediments are both a sink and source of PCBs in the estuary. This research project will address those toxic pollutants that strongly sorb to particulates (i.e., sediments and soils) and have a significant contribution from both point sources and non-point sources including stormwater runoff, hazardous waste site releases and atmospheric deposition. PCBs were recently identified using low level, congener-specific analytical methods in several tributaries including the Schuylkill River and in effluents from six large municipal wastewater treatment plants. The Commission, in cooperation with the U.S. Environmental Protection Agency, Region III and the states bordering the estuary recently developed a strategy to address the PCB contamination in the estuary that includes monitoring of potential sources and living resources.