Suspended particulates and natural radionuclides as tracers of pollutant transports in Continental Shelf waters of the Eastern U.S.A

Preliminary results are reported from a study of the dispersion of anthropogenic pollutants by examining the suspended particulate phases with which many pollutants are associated and on which they are transported in the marine environment. The populations of suspended particle types, their distributions and their associations with trace metal pollutants have been analyzed by examining individual particles using combined scanning electron microscopy (SEM) and energy-dispersive x-ray fluorescence (EDXRF). The distribution of discrete pollutant particles, e.g., Ti-oxides and trace-metal bearing organic particles, which have their origins in the Apex of the New York Bight, suggest paths by which these pollutants are dispersed across the continental shelf. Gross features of surface and near-bottom suspended particle concentrations reflect vertical and horizontal mixing processes and indicate a flux of particles both into and out of the sediments. The distribution of 222Rn, a naturally radioactive tracer, which also has a flux from the sediments (particularly fine-grained sediments), was similar to that of near-bottom suspended particles. It was concluded that modelling the dispersion of radon will yield information on the rates of dispersion and removal of suspended particulates from the water column