Mercury pollution is a global environmental problem that has received considerable attention since the Minamata case in Japan in the late fifties. National and international efforts have been undertaken to understand the mechanisms at play that lead to the biogeochemical transformation of Hg in aquatic ecosystems and the formation of methyl mercury (CH3-Hg+) which is one of the most potent neurotoxin known to humans. The biosynthesis of Me-Hg by a variety of microbial species in aquatic systems stress the need that we have to understand better how Hg enters single cell organisms. In parallel, the fabrication and utilization of many ligands for various industrial applications tend to foster the mobilization of metals in aquatic systems. The conventional perspective is to assume that when metals are complexed by strong ligands they are not bioavailable. Therefore, one can assume that even if metal mobility is enhanced, metal-ligand chelates represent little threat to aquatic systems. Recent observations that we have made on the bioavailability of Hg in presence of various ligands such as EDTA â€“ which is widely use in the industry and in food products â€“ and other biogenic ligands challenge this concept. The overall goal of this research is to advance our understanding of how Hg becomes bioavailable in the presence of anthropogenic and biogenic ligands. The research team composed of the PI, one Ph.D. student and one undergraduate will 1. use well controlled laboratory experiments to determine, using a bioreporter system the fraction of Hg, that is taken up by microbial cells; 2. extend the application of these laboratory experiments to field conditions where the chemical make-up of the aquatic system is controlled by natural processes; and 3. determine the processes that are responsible for the binding and transfer of Hg from the solution to the interior of the cell where its chemical speciation can later be modified. These objectives will be accomplished by using state of the art analytical methods such as voltammetric measurements and x-ray absorption spectroscopy.
|Effective start/end date
|9/15/13 → 8/31/17
- National Science Foundation (CHE-1308504)
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