PCB CONCENTRATIONS IN VIRGINIA TRIBUTARIES TO THE CHESAPEAKE BAY

Over the past 20 years, reports have been made of elevated PCB measurements in both the Rappahanock River Watershed (more populated and more wastewater treatment plants) and the York River Watershed (less populated and more factories). These rivers carry sediment from the Appalachian Mountains, across the rolling hills of the Piedmont Province, and into the Virginiaa side of the Chesapeake Bay. All of our fine-grained river sediments contained measurable amounts of PCB's. In the Rappahannock River samples, approximately 15% of the Total PCB's came from industrial areas, 25% from mixed land-use areas, 10% from agricultural areas, and 50% from urban areas. In the York River samples, approximately 75% of the Total PCB's came from industrial areas, 15% from mixed land-use areas, 10% from agricultural areas, and none from urban areas. Fortunately, although some samples were very high in PCB concentrations compared to samples from most of the sites, no sites exceeded the US-EPA Recommended Maximum Concentrations (Toxic Control Act, TSCA). The present situation probably exists because, with rare exception, PCB's are no longer made and used in significant amounts, and while PCB's do not significantly degrade over time, they do become diluted and increasingly deeply covered by the constant movement of river sediments.