Insights from the spatial and temporal distributions of mercury species and isotopes in bivalves from the french coastline
|Author(s)||Briant Nicolas, Knoery Joel, Chouvelon Tiphaine, Brach-Papa Christophe, Chiffoleau Jean-Francois, Savoye Nicolas, Sonke Jeroen|
|Affiliation(s)||Laboratoire de Biogéochimie des Contaminants Métalliques, IFREMER, Centre Atlan1que, F-44311, Nantes Cedex 3, France
Université Bordeaux, EPOC, UMR 5805, F-33400 Talence, France
Observatoire Midi-Pyrénées, laboratoire Géosciences Environnement Toulouse, CNRS/IRD/université Paul-Saba1er, 14, avenue Edouard-Belin, F-31400 Toulouse, France
|Meeting||ICMGP 2017 - 13th International Conference on Mercury as a Global Pollutant. July 16-21, 2017, Rhode Island|
Mercury cycles between atmosphere, terrestrial and aquatic reservoirs through a complex combination of transport and transformation processes, until it is buried in oceanic or terrestrial sediments. Monomethylmercury is the main species bioaccumulated and bioampli ed in the food chain. Knowledge of the origin (continental, oceanicorlocalsediment)ofthisspeciesforthelittoralenvironnment can still be improved.
This study focuses on ~200 samples of bivalves (mussels: Mytilus edulis and Mytilus galloprovincialis and oysters: Crassostrea gigas
In the bivalves, we observed that the variations in methylmercury concentrations follow linearly those of total mercury (HgT). Preliminary results of isotopic fractionation of HgT in some of the samples do show regional e ects and allow to differentiate English Channel, Atlantic, and Mediterranean coastlines. These differences may come from the various trophic regimes revealed by nC stable isotopes, from different fractionnation by the three biological species of bivalves, from different mercury source isotopic signatures, or both.
At most of the study sites, HgT concentrations have not decreased since 1987, despite regulations to abate or ban mercury used by anthropic activities.
This study is part of the Trococo project, funded by Ifremer, rgion Pays de la loire (Pollusols), and Insu/EC2CO/Dril.