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Tytuł:
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Mercury Isotope Fractionation by Internal Demethylation and Biomineralization Reactions in Seabirds: Implications for Environmental Mercury Science.
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Autorzy:
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Manceau A; Université Grenoble Alpes, ISTerre, CNRS, 38000 Grenoble, France.
Brossier R; Université Grenoble Alpes, ISTerre, CNRS, 38000 Grenoble, France.
Janssen SE; Upper Midwest Water Science Center, U.S. Geological Survey, Middleton, Wisconsin 53562, United States.
Rosera TJ; Upper Midwest Water Science Center, U.S. Geological Survey, Middleton, Wisconsin 53562, United States.
Krabbenhoft DP; Upper Midwest Water Science Center, U.S. Geological Survey, Middleton, Wisconsin 53562, United States.
Cherel Y; Centre d'Etudes Biologiques de Chizé (CEBC), CNRS, La Rochelle Université, 79360 Villiers-en-Bois, France.
Bustamante P; Littoral Environnement et Sociétés (LIENSs), CNRS-La Rochelle Université, 17000 La Rochelle, France.
Poulin BA; Department of Environmental Toxicology, University of California Davis, Davis, California 95616, United States.
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Źródło:
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Environmental science & technology [Environ Sci Technol] 2021 Oct 19; Vol. 55 (20), pp. 13942-13952. Date of Electronic Publication: 2021 Oct 01.
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Typ publikacji:
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Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.
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Język:
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English
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Imprint Name(s):
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Publication: Washington DC : American Chemical Society
Original Publication: Easton, Pa. : American Chemical Society, c1967-
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MeSH Terms:
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Mercury*/analysis
Methylmercury Compounds*
Water Pollutants, Chemical*/analysis
Animals ; Biomineralization ; Birds ; Chemical Fractionation ; Demethylation ; Environmental Monitoring ; Humans ; Mercury Isotopes/analysis
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Contributed Indexing:
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Keywords: Bird; Isotope fractionation; Mercury; Toxicology
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Substance Nomenclature:
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0 (Mercury Isotopes)
0 (Methylmercury Compounds)
0 (Water Pollutants, Chemical)
FXS1BY2PGL (Mercury)
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Entry Date(s):
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Date Created: 20211001 Date Completed: 20211028 Latest Revision: 20220408
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Update Code:
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20240105
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DOI:
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10.1021/acs.est.1c04388
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PMID:
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34596385
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A prerequisite for environmental and toxicological applications of mercury (Hg) stable isotopes in wildlife and humans is quantifying the isotopic fractionation of biological reactions. Here, we measured stable Hg isotope values of relevant tissues of giant petrels ( Macronectes spp.). Isotopic data were interpreted with published HR-XANES spectroscopic data that document a stepwise transformation of methylmercury (MeHg) to Hg-tetraselenolate (Hg(Sec) 4 ) and mercury selenide (HgSe) (Sec = selenocysteine). By mathematical inversion of isotopic and spectroscopic data, identical δ 202 Hg values for MeHg (2.69 ± 0.04‰), Hg(Sec) 4 (-1.37 ± 0.06‰), and HgSe (0.18 ± 0.02‰) were determined in 23 tissues of eight birds from the Kerguelen Islands and Adélie Land (Antarctica). Isotopic differences in δ 202 Hg between MeHg and Hg(Sec) 4 (-4.1 ± 0.1‰) reflect mass-dependent fractionation from a kinetic isotope effect due to the MeHg → Hg(Sec) 4 demethylation reaction. Surprisingly, Hg(Sec) 4 and HgSe differed isotopically in δ 202 Hg (+1.6 ± 0.1‰) and mass-independent anomalies (i.e., changes in Δ 199 Hg of ≤0.3‰), consistent with equilibrium isotope effects of mass-dependent and nuclear volume fractionation from Hg(Sec) 4 → HgSe biomineralization. The invariance of species-specific δ 202 Hg values across tissues and individual birds reflects the kinetic lability of Hg-ligand bonds and tissue-specific redistribution of MeHg and inorganic Hg, likely as Hg(Sec) 4 . These observations provide fundamental information necessary to improve the interpretation of stable Hg isotope data and provoke a revisitation of processes governing isotopic fractionation in biota and toxicological risk assessment in wildlife.
Comment in: Environ Sci Technol. 2022 Feb 1;56(3):2069-2070. (PMID: 35060386)
Comment in: Environ Sci Technol. 2022 Feb 1;56(3):2065-2068. (PMID: 35060387)
