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Distribution and accumulation of mercury in tissues of captive‐reared common loon ( Gavia immer ) chicks
Author(s) -
Kenow Kevin P.,
Meyer Michael W.,
Hines Randy K.,
Karasov William H.
Publication year - 2007
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1897/06-193r.1
Subject(s) - methylmercury , feather , mercury (programming language) , chemistry , bioaccumulation , zoology , excretion , tissue distribution , feces , toxicokinetics , mercure , urine , body weight , biology , endocrinology , environmental chemistry , metabolism , biochemistry , ecology , physiology , analytical chemistry (journal) , computer science , programming language
Abstract We determined the distribution and accumulation of Hg in tissues of common loon ( Gavia immer ) chicks maintained for up to 15 weeks on either a control diet with no added methylmercury chloride (MeHgCl) or one containing either 0.4 or 1.2 μg Hg (as MeHgCl)/g wet‐weight food. Total Hg and MeHg tissue concentrations were strongly positively correlated ( r 2 > 0.95) with the amount of Hg delivered to individual chicks throughout the course of the experiment. The pattern of differential Hg concentration in internal tissues was consistent within each treatment: Liver > kidney > muscle > carcass > brain. Feather Hg concentrations were consistently higher than those of internal tissues and represented an important route of Hg elimination. Feather mass accounted for 4.3% ± 0.1% (average ± standard error) of body mass, yet 27.3% ± 2.6% of total Hg intake was excreted into feathers. Our calculations indicate that 26.7% ± 4.9% of ingested Hg was not accounted for and, thus, either was never absorbed or was absorbed and subsequently eliminated in feces. With the additional excretion into feathers, 54% of ingested Hg was excreted. Demethylation was evident in the liver at all treatment levels and in the kidneys of chicks dosed at 1.2 μg Hg/g. Mercury concentrations were strongly positively correlated ( r 2 ≥ 0.95) among internal tissues and with blood Hg concentration. Mercury concentrations of secondary feathers were moderately correlated ( r 2 = 0.82–0.93) with internal tissues. We supply regression models that may be used to provide perspective and a useful means of interpreting the variety of measures of Hg exposure reported in the literature.