title: Silver speciation in liver of marine mammals by synchrotron X-ray absorption fine structure and X-ray fluorescence spectroscopies.
abstract: The chemical form of Ag in the livers of five species of marine mammals was examined using X-ray absorption fine structure (XAFS) and X-ray fluorescence (XRF) spectroscopies. The XAFS analysis suggested that Ag(2)Se was present in the livers of the Franciscana dolphin (Pontoporia blainvillei), Dall's porpoise (Phocoenoides dalli), and Baird's beaked whale (Berardius bairdii), whereas Ag(2)S was present in the livers of the striped dolphin (Stenella coeruleoalba) and pygmy killer whale (Feresa attenuata). XRF spectroscopy results revealed that the distribution patterns of Ag and Se in a thin section of the liver of the Franciscana dolphin were the same; this also implied that Ag was associated with Se in the liver. Thus, the interaction of Ag with Se or S may offer significant protection against the toxicity of Ag in marine mammals. The formation of either Ag(2)Se or Ag(2)S might depend on the Hg levels in the liver. Ag(2)Se was observed in liver samples with relatively high Ag/Hg ratio, whereas liver samples with low Ag/Hg ratio contained Ag(2)S.
authors.affiliation: Department of Applied Chemistry, Tokyo University of Science, Kagurazaka 1-3, Shinjuku-ku, Tokyo, 162-8601, Japan.
authors.forename: Emiko
authors.initials: E
authors.lastname: Nakazawa
authors.forename: Tokutaka
authors.initials: T
authors.lastname: Ikemoto
authors.forename: Akiko
authors.initials: A
authors.lastname: Hokura
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Terada
authors.forename: Takashi
authors.initials: T
authors.lastname: Kunito
authors.forename: Takahito
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Tadasu K
authors.initials: TK
authors.lastname: Yamada
authors.forename: Fernando C W
authors.initials: FC
authors.lastname: Rosas
authors.forename: Gilberto
authors.initials: G
authors.lastname: Fillmann
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Tanabe
authors.forename: Izumi
authors.initials: I
authors.lastname: Nakai
mesh_terms: D000818:Animals; D004289:Dolphins / Q000378:metabolism*; D005260:Female; D008099:Liver / Q000737:chemistry* / Q000378:metabolism; D008297:Male; D012643:Selenium / Q000737:chemistry; D012834:Silver / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D013052:Spectrometry, X-Ray Emission; D013455:Sulfur / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D014907:Whales / Q000378:metabolism*; D056928:X-Ray Absorption Spectroscopy
chemical_list: D014874:Water Pollutants, Chemical; D012834:Silver; D013455:Sulfur; D012643:Selenium