Simulation of marine ecosystem effects due to PCB waste incineration in the Gulf of Mexico

Abstract

A four-level atmosphere—ocean-sediments transport model has been coupled to an ecosystem model to estimate the magnitude of effects of ocean-based incineration of PCB wastes. The atmospheric (top) layer of the model has a seasonally variable thickness, a reflecting boundary at the top, and an absorbing boundary at the air—water interface. Both wet and dry deposition are included. Rainfall occurs stochastically. Upper and lower layers of the oceanic water column constitute the second and third layers of the transport model, while the sediments on the seafloor are the fourth layer. Adsorption of pollutants to particulate matter in the water column, and resuspension of pollutants in shallow coastal regions are included. The ecosystem model focuses on linkages among major trophic compartments, and includes predation, metabolic, and pollutant assimilation/depuration components. Simulation results suggest that, for destruction and removal efficiencies (DRE) on the order of 0.9999 (‘four nines’), measurable bioaccumulation effects may occur in the benthos over a 50-year policy horizon, whereas if a DRE of six nines can be established and maintained, effects will be negligible. Efficiency monitoring and control during the incineration process is therefore of primary importance if a policy of ocean incineration of hazardous wastes is to be adopted on a large scale.