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(55-06) Influence of vegetation on the distribution of semi-volatile chemicals in a dynamic global multimedia model. Wegmann, Fabio*,1, Möller, Matthias1, Scheringer, Martin1, Hungerbühler, Konrad1, 1 Safety & Environmental Technology Group, Zurich, Switzerland ABSTRACT- Several regional models for persistent organic pollutants (POPs) deal with vegetation because vegetation is either a major compartment in the model system considered or is important for human exposure pathway estimations. However, there are only few modelling studies dealing with the global influence of vegetation on POPs behaviour. We present CliMoChem, a dynamic global multimedia transport model with a flexible number of climatic zones, each containing soil, ocean surface water and troposphere. Every zone is individually parameterised (temperature course, vegetation types etc.). We included sorption into the lipophilic fraction of the foliage, neglecting stems, roots and other vegetation capacities. Various kinetic transfer processes for the vegetation, soil and air compartment are incorporated into the model. Since there is a wide range of experimental findings showing plant specific influences, we distinguish among several vegetation types in the model. Although foliage does not have a high storage capacity for POPs due to its small relative volume, kinetic effects such as the forest filter effect may strongly influence the global substance distribution pattern by transferring substances from the air through foliage into the soil, thereby reducing the potential for long-range transport. Since transport to polar regions is an important focus of the model, we discuss the effect of vegetation on a substance′s potential for long-range transport and cold condensation. While single-pulse emissions provide a basic model understanding, real emission patterns are more complex. We have compiled a historical emission inventory for DDT from a variety of sources. The influence of vegetation on DDT fate is investigated using this emission inventory. An existing inventory for Key words: long-range transport, vegetation, DDT, multimedia modelling |
-HCH is used for comparison. The effect of vegetation on partitioning, transport and persistence of the chemicals is discussed.