The Influence of Long-term Mercury Exposure on Selenium Availability in Tissues: An Evaluation of Data |
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Authors: | Ingrid Falnoga Magda Tušek-Žnidarič Peter Stegnar |
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Institution: | (1) Department of Environmental Sciences, Jožef Stefan Institute, Jamova 39, Ljubljana, 1111, Slovenia |
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Abstract: | The precise mechanisms of mercury accumulation and retention are still unclear. Generally, the association of mercury with
selenium is used to explain these phenomena. It seems that the presence of coaccumulated endogenous Se can protect cells from
the harmful effects of Hg. However, as speculated by some authors, this binding of Se to Hg can also result in a relative
deficiency of biologically available Se needed for selenoenzyme syntheses. Deriving from the assumption that Hg deposited
in tissues is bound to Se in a 1:1 ratio, the quantity of non-Hg bound Se could be calculated by the difference between the
molar contents of the two elements (Semol–Hgmol). In this study we applied such an approach to the data from our previous investigation, where Hg and Se concentrations were
determined in autopsy samples of mercury exposed retired Idrija mercury mine workers, Idrija residents living in a Hg contaminated
environment and a control group with no known Hg exposure from the environment. Based on these data we tried to estimate the
influence of Hg exposure on the physiologically available selenium content in selected tissues, particularly endocrine glands
and brain tissues. Comparing the calculated values of (Semol– Hgmol) it was found that for Idrija residents the values were similar to those of the control group and as expected, diminished
values were found in some mercury-loaded organs of retired Idrija miners. It could be speculated that in Idrija residents
Hg sequestration of selenium is sufficiently compensated by increased Se levels, but that particularly in active miners and
in some organs of retired miners, the activity and/or synthesis of selenoenzymes could be disturbed.
Part of the study was presented at the 7th International Conference on Mercury as a Global Pollutant, June 27–July 2, 2004
Ljubljana, Slovenia (Falnoga et al. 2000) |
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Keywords: | autopsy tissues brain endocrine glands mercury vapour selenium mercury interaction |
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