Enrico, Maxime and Le Roux, Gaël
and Heimbürger, Lars-Éric and Van Beek, Pieter and Souhaut, Marc and Chmeleff, Jérôme and Sonke, Jeroen
Holocene Atmospheric Mercury Levels Reconstructed from Peat Bog Mercury Stable Isotopes.
(2017)
Environmental Science & Technology, 51 (11). 5899-5906. ISSN 0013-936X
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(Document in English)
PDF - Requires a PDF viewer such as GSview, Xpdf or Adobe Acrobat Reader 362kB |
Official URL: https://doi.org/10.1021/acs.est.6b05804
Abstract
Environmental regulations on mercury (Hg)emissions and associated ecosystem restoration are closely linked to what Hg levels we consider natural. It is widely accepted that atmospheric Hg deposition has increased by a factor 3 ± 1 since preindustrial times. However, no long-term historical records of actual atmospheric gaseous elemental Hg (GEM) concentrations exist. In this study we report Hg stable isotope signatures in Pyrenean peat records (southwestern Europe) that are used as tracers of Hg deposition pathway (Δ200Hg, wet vs dry Hg deposition) and atmospheric Hg sources and cycling (δ202Hg, Δ199Hg). By anchoring peatderived GEM dry deposition to modern atmospheric GEM levels we are able to reconstruct the first millennial-scale atmospheric GEM concentration record. Reconstructed GEM levels from 1970 to 2010 agree with monitoring data, and maximum 20th century GEM levels of 3.9 ± 0.5 ng m−3 were 15 ± 4 times the natural Holocene background of 0.27 ± 0.11 ng m−3. We suggest that a −0.7‰ shift in δ202Hg during the medieval and Renaissance periods is caused by deforestation and associated biomass burning Hg emissions. Our findings suggest therefore that human impacts on the global mercury cycle are subtler and substantially larger than currently thought.
Item Type: | Article |
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Audience (journal): | International peer-reviewed journal |
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Institution: | French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE) Université de Toulouse > Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE) French research institutions > Institut de Recherche pour le Développement - IRD (FRANCE) Université de Toulouse > Université Toulouse III - Paul Sabatier - UT3 (FRANCE) |
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Deposited On: | 20 Nov 2018 09:54 |
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