Modeling Marine Exposure to Polychlorinated Biphenyls from Sunken Ships

In the past, the U.S. Navy has routinely conducted SINKing EXercises (SINKEX) for training, weapon effectiveness tests, and economic disposal of aging assets. Recent concern over polychlorinated biphenyl (PCB) chemicals aboard such target vessels has resulted in a suspension of SINKEX. The U.S. Navy has approximately 200 vessels currently requiring such disposal. Environmental legislation and health concerns preclude selling such vessels to foreign governments or scrapping. This work attempted to model the fate and transport of these PCBs by examining their transport to coastal water and their accumulation in the marine food chain. The model includes biodegradation, upwelling, partitioning of PCBs to sediment, sediment transport, bioaccumulation, biomagnification, and biological migration. Seasonal fluctuations in marine biomass and storm activity and how this affects PCB concentrations is also examined. The model uses a four trophic level approach for the marine food chain. A total of 55 runs, each simulating a 50 year period, were conducted. Model output and subsequent sensitivity analysis of parameters indicate that the potential for adverse impact to the marine ecosystem is minimal