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1G - Long-range transport of pollutants (chemicals) (WE13/11) Influence of Vegetation in a Global Multimedia POPs Model and its Implications for Long-range Transport. Wegmann, Fabio1, Scheringer, Martin1, Hungerbühler, Konrad1, 1 Federal Institute of Technology, ETH, Zurich, ZH, Switzerland ABSTRACT- We use our dynamic global multimedia transport model CliMoChem to investigate the influence of vegetation on POPs fate and transport. CliMoChem consists of a flexible number of climatic zones, each containing soils, ocean surface water, troposphere and canopy. Each zone is individually parameterised using remote sensing and other data (land cover types, temperature courses, etc). Vegetation is included as a foliage compartment above the soil, with an absorptive capacity into the lipophilic fraction of the canopy, neglecting other capacities such as stems and roots. A set of kinetic processes for foliage is included into the model and parameterised for individual vegetation types, since a variety of parameter values have been presented in the literature for different vegetation types. While there is only a limited storage capacity in the foliage due to its small volume, kinetic properties of the canopy are important. Depending on these properties, a Forest Filter Effect and a Shielding Effect are observed. The former effect lowers the long-range transport potential, while the latter enhances the long-range transport potential due to the reduced deposition to the ground. The occurrence of these effects is determined by highly uncertain parameters (such as the particle-bound fraction in air, the degradation rate constant in vegetation or the organic matter content in the soil). A further investigation of the significance of other uncertain parameters such as the air-foliage diffusion rate constant is presented. In addition, we explore the importance of the organic matter content of the vegetation soil on POPs behaviour, both with and without a canopy compartment. Key words: multimedia modelling, vegetation, long-range transport, persistent organic pollutant |
