PM07 Pollutant Chemistry Transport, Cycling and Fate
Exhibit Hall
8:00 AM - Monday
(PM075) Decachlorobiphenyl: Using a non-Aroclor PCB as a tracer of estuarine processes.
Baker, J.1, Toaspern, M.1, Liebert, D.1, Ko, F.1, 1 University of Maryland Chesapeake Biological Laboratory, Solomons, Maryland, USA
ABSTRACT- Decachlorobiphenyl (IUPAC congener number 209), the perchlorinated biphenyl congener, was not produced in appreciable quantities in any of the Aroclor™ or other commercial products. There are no known pathways by which lesser chlorinated PCBs can react to form PCB 209 in the environment. In our studies in the Delaware River and Bay and the upper Chesapeake Bay (which are connected via the Chesapeake and Delaware Canal), we have often observed that PCB 209 is a significant fraction of the congener mixture comprising the total PCB concentrations in sediments, suspended solids, and fish. For example, PCB 209 is about 10% of the total PCB burden in sediments and in prey items in the food web of the lower Delaware River below Philadelphia. Octa- and nonachlorbiphenyl congeners are also unusually enriched in these samples, suggesting a local 'non-Aroclor' source of these PCB congeners. A titanium dioxide purification facility located on the lower Delaware that used a carbochlorination process may have contributed these congeners to the system. Concentrations of PCB 209 in sediments and biota decrease with distance away from the lower Delaware River, but are still enriched relative to Aroclor mixtures throughout much of the Chesapeake and Delaware Canal and the upper Chesapeake Bay. PCB 209 is strongly bound to sediments and accumulates in food webs, and may therefore be used as a tracer of sediment transport and bioaccumulation in the Delaware and Chesapeake Bays. In this paper, we present a simple mixing model based on PCB 209 concentrations to estimate the amount of sediment exchange through the Chesapeake and Delaware Canal and to investigate white perch dispersal patterns.
Key words: Delaware, PCB, Chesapeake, tracer