This award will support collaborative research between James Weber, University of New Hampshire, and Dr. Michael Bernhard, Centro Richerche Energia Ambiente (ENEA), in La Spezia, Italy. ENEA is leading a major Swedish, German, and Italian study on environmental methylmercury concentrations. Weber will work with Bernhard on the methylation and demethylation of mercury compounds in sediments. The research will emphasize addition of labeled inorganic mercury and methylmercury to sediment microcosms with the goal of understanding biotic and abiotic mercury methylation processes. The results of the collaboration should provide increased understanding of mechanisms of mercury transformations, and of the sources and quantities of methylmercury in sediments, and their transfer into the water and biota. This knowledge could allow for assessment of potential environmental hazards associated with methylmercury in biota. In addition, this project would be an important initial step toward establishing a basis for estimating methylmercury production and establishing environmental quality criteria for it. Studies will be conducted under a variety of conditions including: 1) addition or no addition of mercury compounds, 2) inhibition or stimulation of certain bacteria, 3) aerobic or anaerobic conditions, and 4) addition or no addition of potential methyl donors. Weber will contribute to the project fundamental knowledge of chemical mechanisms involving organometallic compounds and experience in developing techniques for determining low nanogram and picogram amounts of methyl- and butylin compounds in a wide variety of environmental samples. ENEA personnel will contribute general knowledge of formation and demethylation of methylmercury in the Gulf of Genoa and the Ligurian Sea and rivers draining into them, expertise on biological aspects of the processes, and considerable experience with use of radioactive isotopes, and equipment for measuring them.
