Toxicology of selenium: a review

Area of Science:

• Environmental Science
• Toxicology
• Biogeochemistry

Background:

• Selenium concentration is highly site-specific, rendering global averages impractical.
• Aquatic organisms exhibit varied correlations between water and tissue selenium levels.
• Some organisms bioaccumulate selenium significantly, up to 3800 times the water concentration.

Purpose of the Study:

• To investigate selenium concentrations and bioaccumulation in aquatic environments.
• To explore the relationship between environmental selenium and organismal tissue levels.
• To assess the potential for selenium biomagnification and its protective effects.

Main Methods:

• Analysis of selenium concentrations in water and aquatic organisms.
• Correlation studies between environmental and tissue selenium levels.
• Observation of bioaccumulation factors and potential biomagnification.

Main Results:

• Aquatic organisms from seleniferous regions bioconcentrate selenium, reaching high tissue levels.
• Bioaccumulation factors range from 1300 to 3800 in some species.
• No evidence of selenium biomagnification in aquatic food chains was found.
• Selenium demonstrates protective effects against heavy metal and organic toxicant poisoning.

Conclusions:

• Selenium's environmental impact and biological effects are localized and complex.
• While bioaccumulation occurs, biomagnification is not a significant concern for selenium.
• Selenium plays a role in mitigating heavy metal toxicity.
• Selenium is a necessary micronutrient, though human requirements are not fully established.