The objectives are: to identify the biotic and abiotic matrices in terrestrial, freshwater and marine ecosystems in which the transformation of inorganic mercury to methylmercury and of methylmercury to other mercury species occur; to quantify these chemical, physical, and biological transformation processes; to determine the pathways of methylmercury in various ecosystems; and to elaborate environmental quality criteria for methylmercury.
In a comparative approach, methylmercury and other inorganic and organic mercury species will be identified and quantified in key components of typical foodchains of terrestrial, freshwater and marine ecosystems situated in different geographical areas of Europe which are either not exposed (background) or are exposed to atmospheric, industrial and/or natural mercury sources. Air, rain, surface water, sediments and biota from the Swedish lake area, industrial and remote sites in Germany, North Sea coast, Elbe and Weser estuaries, La Spezia area, the Gulf of Genoa and the Mount Amiata region will be compared to evaluate the relative importance of methylmercury pollution.
In an experimental approach, information from the comparative approach will be used to investigate methylation and demethylation processes of mercury in 2 and higher compartment systems, applying in laboratory and in situ experiments stable isotope (mercury-199) and radioisotope (mercury-197 and mercury-203) techniques. These experiments also intend to differentiate between biotic and abiotic methylation processes under natural conditions.
Improvement of the sensitivity of existing analytical techniques for the determination of inorganic mercury and methylmercury in environmental matrices at ultra low concentrations (picogram level) will be attempted.
In a simulation approach the data generated in the comparative and experimental approaches will be used as inputs to conceptual and mathematical models to predict the distribution and fluxes of inorganic mercury and methylmercury in typical food chains, with particular emphasis on the fate of atmospheric mercury loads. The modelling results will lay the basis for recommending environmental quality criteria for methylmercury.
Funding SchemeCSC - Cost-sharing contracts