T9.5. Mercury stable isotope biogeochemistry
At the GET we have been exploring since 2005 the stable isotopic variations of mercury (Hg) in the natural environment. Our main objective is to use Hg isotope and speciation information to better understand the impact of anthropogenic Hg in our environment. In addition we are interested in understanding Hg isotope fractionation mechanisms and develop potential paleogeochemical applications. Hg isotopes as tracers for processes and sources are promising due to the multitude of mass dependent (MDF) and mass independent (MIF) isotope fractionation processes.
With seven stable isotopes, no less than four useful isotope signatures, δ202Hg, Δ199Hg, Δ200Hg, Δ201Hg, are available to quantify Hg cycling between the Earth’s surface reservoirs.
Our recent work has characterized the isotopic compositions of volcanic Hg emissions (Zambardi et al. 2009), the relationship between fish diet and hair mercury isotope signatures in Amazonian river people and gold miners (Laffont et al. 2009, 2011), the influence of climate change on the Arctic mercury cycle (Point et al. 2011), and a global model of mercury MIF (Sonke, 2011). Without exception, all of our studies involve collaborators at the OMP (LA, LEGOS, EcoLab), in France (CRPG, IPREM) or internationally (NIST, CAS, UMSA, etc.).
Our ongoing projects (ANR MERCY, ANR RIMNES, ERC MERCURY ISOTOPES, ECCO COMIBOL) continue to explore Hg isotopes as tracers in extreme environments (Titicaca Lake-Bolivian Altiplano and the French Pic du Midi), in tropical environments, as a human exposure tracer in Guyana and China, and as anthropogenic emission tracers for sources such as coal fired power plants.
Contacts: Jeroen Sonke, Laurence Maurice , David Point
Laffont, L., Sonke, J.E., Maurice Bourgoin, L., Hintelmann, H., Pouilly, M., Sanchez-Bacarreza, Y., Perez, T., Behra, Ph. (2009) Effects of fish diet on anomalous mercury isotopic compositions of human hair in the Bolivian Amazon. Environmental Science and Technology, v.43, p.8985.
Zambardi, T., Sonke, J.E., Toutain, J-P., Sortino, F. Shinohara, H.(2009) Mercury emissions and stable isotopic compositions at Vulcano Island (Italy). Earth and Planetary Science Letters, Vol. 277, p.236.
Sonke, J.E. (2011). A global Hg isotope box-model for mass-independent Hg isotope fractionation. Geochimica et Cosmochimica Acta, v75, p4577-4590.
Point, D., Sonke, J.E, Day, R.D., Rosenau, D.G., Hobson, K.A., Vanderpol, S.S., Moors, A.J., Pugh, R.S., Donard, O. F. X., and Becker, P. B., (2011). Methylmercury photodegradation influenced by sea ice cover in Arctic marine ecosystems. Nature Geoscience, v4, p188-194.