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(15-20) Relationships between atmospheric deposition, transfer to the deep sea, and long-range transport potential of POPs. Scheringer, Martin*,1, Stroebe, Maximilian1, Wegmann, Fabio1, Hungerbühler, Konrad1, Wania, Frank2, 1 Swiss Federal Institute of Technology, Zürich, Switzerland2 University of Toronto at Scarborough, Toronto, Canada ABSTRACT- The long-range transport (LRT) potential of semivolatile chemicals such as PCBs is determined by several factors such as deposition, degradation, revolatilization, transfer to the deep sea etc. The complex interplay of these factors has not been completely understood so far. Here, we focus on the relationship between LRT, on the one hand, and atmospheric wet and dry deposition and deposition from the oceanic surface water to the deep sea by suspended particles, on the other hand. For several persistent organic pollutants (POPs), e.g. selected PCB congeners, DDT, and hexachlorobenzene, we investigate the spatial range as a measure of LRT potential with the multimedia fate and transport model Chemrange. Chemrange contains tropospheric air, oceanic surface water and soil and simulates the global circulation of a chemical in a simplified circular ''world''. For semivolatile chemicals, the model results show that both types of processes, atmospheric deposition and particle settling in the oceans, can have significant influence on the LRT potential. The effect of different factors such as particle concentrations in water and air, deposition velocities, degradability of adsorbed fraction in air and partition coefficients Koa and Koc of the chemicals, is analyzed. The long-range transport of POPs is discussed with respect to the efficiency of transport in water and air, the interplay between transport, deposition and, for air, revolatilization, and the mobile fractions of the amount released. Key words: long-range transport, deposition, multimedia models |
