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Mercury species over Europe. Relative Importance of depositional methylmercury fluxes to various ecosystems.


The general objective is to identify and quantify sources of atmospheric mercury species focusing on production and fluxes of methylmercury (MeHg). The primary objective is to find the relative importance of the atmospheric deposition of MeHg, in comparison to methylation/demethylation processes in terrestrial and limnic ecosystems, in various parts of Europe. The intention is to provide the missing important pieces on the occurrence of direct and diffuse emissions, and of atmospheric production, of the mercury species contributing to the MeHg found enriched at different trophic levels in our ecosystems. From this, the capability of MeHg of atmospheric origin to act as a net source for MeHg transport over transition zones between, terrestrial, wetland, and limnic ecosystems, will be assessed. The information will be necessary in constructing adequate multicompartment models for the fate and effects of ecotoxicologically relevant mercury species, e.g. MeHg, and assessing impacts from environmental changes. For this purpose, techniques for identifying and quantifying the potential sources of atmospheric MeHg and other relevant mercury species, will be developed and used, In particular, possible direct MeHg releases form fossil-fuelled combustion facilities and household waste incinerators, or alternatively through chemical production in the plumes or in the atmosphere, are of major interest.
The importance of various other mercury species in the formation of MeHg will also be addressed by finding at which distance from the sources the MeHg formation starts. Contributions from both point and diffuse MeHg sources will be estimated and confirmed by field measurements (air, precipitation, soils and natural waters) in the vicinity, far from and unaffected by large mercury emitters. The total strength of European MeHg sources will be assessed by expanding the European mercury emission inventory already available by the MeHg fractions, which will be based on the planned MeHg measurements in various type sources. In addition, more developed and adequate techniques for measuring also other mercury species will greatly improve the available emission inventory. Based on the emission inventory, the importance of atmospheric dispersion and long-range transport of MeHg, and its precursors if formed in the plume or in the free atmosphere, from source areas on the European continent to Scandinavia will be evaluated. Further, the presence of MeHg in marine air at the west-coast of Ireland will be used as a reference, when considering to the ocean as a potential source area for MeHg or its predecessors. The evaluation of MeHg contribution from different sources is expected to provide a basic understanding for formulating an EC policy, relevant abatement strategies, and tools for monitoring emission control, as well as being an important contribution to international negotiations on the reduction of transboundary air pollutants.


Swedish Environmental Research Institute Ltd.

100 31 Stockholm

Participants (3)

21502 Geesthacht
3,Kemigaarden 3
412 96 Goeteborg
Technical Research Centre of Finland
4B,tekniikantie 4B
2044 Espoo