Isotope Fractionation from In Vivo Methylmercury Detoxification in Waterbirds
Cited 10 time in
Cited 12 time in
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Title
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Isotope Fractionation from In Vivo Methylmercury Detoxification in Waterbirds
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Other Titles
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수조류 체내에서 메틸수은 해독에 따른 동위원소 분획
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Authors
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Poulin, Brett A.
Janssen, Sarah E.
Rosera, Tylor J.
Krabbenhoft, David P.
Eagles-Smith, Collin A.
Ackerman, Joshua T.
Stewart, A. Robin
Kim, Eunhee
Baumann, Zofia
Kim, Jeong-Hoon
Manceau, Alain
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Subject
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Chemistry; Geochemistry & Geophysics
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Keywords
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MDF; birds; demethylation; isotopes; mercury
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Issue Date
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2021-05-20
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Citation
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Poulin, Brett A., et al. 2021. "Isotope Fractionation from In Vivo Methylmercury Detoxification in Waterbirds". ACS EARTH AND SPACE CHEMISTRY, 5(5): 990-997.
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Abstract
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The robust application of stable mercury (Hg) isotopes for mercury source apportionment and risk assessment necessitates the understanding of mass-dependent fractionation (MDF) as a result of internal transformations within organisms. Here, we used high energy-resolution X-ray absorption near edge structure spectroscopy and isotope ratios of total mercury (δ202THg) and methylmercury (δ202MeHg) to elucidate the chemical speciation of Hg and the resultant MDF as a result of internal MeHg demethylation in waterbirds. In three waterbirds (Clark’s grebe, Forster’s tern, and south polar skua), between 17 and 86% of MeHg was demethylated to inorganic mercury (iHg) species primarily in the liver and kidneys as Hg-tetraselenolate [Hg(Sec)4] and minor Hg-dithiolate [Hg(SR)2] complexes. Tissular differences between δ202THg and δ202MeHg correlated linearly with %iHg [Hg(Sec)4 + Hg(SR)2] and were interpreted to reflect a kinetic isotope effect during in vivo MeHg demethylation. The product-reactant isotopic enrichment factor (εp/r) for the demethylation of MeHg → Hg(Sec)4 was -2.2 ± 0.1‰. δ202MeHg values were unvarying within each bird, regardless of Hg(Sec)4 abundance, indicating fast internal cycling or replenishment of MeHg relative to demethylation. Our findings document a universal selenium-dependent demethylation reaction in birds, provide new insights on the internal transformations and cycling of MeHg and Hg(Sec)4, and allow for mathematical correction of δ202THg values as a result of the MeHg → Hg(Sec)4 reaction.
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URI
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https://repository.kopri.re.kr/handle/201206/12979
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DOI
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http://dx.doi.org/10.1021/acsearthspacechem.1c00051
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Type
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Article
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Station
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Jang Bogo Station
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Indexed
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SCIE
- Appears in Collections
- 2020-2020, Ecosystem Structure and Function of Marine Protected Area (MPA) in Antarctica (20-20) / Kim, Jeong-Hoon (PM20060)
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