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Isotope Fractionation from In Vivo Methylmercury Detoxification in Waterbirds

Cited 4 time in wos
Cited 4 time in scopus
Title
Isotope Fractionation from In Vivo Methylmercury Detoxification in Waterbirds
Other Titles
수조류 체내에서 메틸수은 해독에 따른 동위원소 분획
Authors
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
Subject
ChemistryGeochemistry & Geophysics
Keywords
MDFbirdsdemethylationisotopesmercury
Issue Date
2021-05-20
Citation
Poulin, Brett A., et al. 2021-05-20. "Isotope Fractionation from In Vivo Methylmercury Detoxification in Waterbirds". ACS EARTH AND SPACE CHEMISTRY, 5(5): 990-997.
Abstract
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.
URI
https://repository.kopri.re.kr/handle/201206/12979
DOI
http://dx.doi.org/10.1021/acsearthspacechem.1c00051
Type
Article
Station
Jang Bogo Station
Indexed
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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