A Novel Approach to Estimate Mercury Exposure Risks Through Fish Consumption Based on the Selenium-Mercury Molar...

Area of Science:

• Environmental Science
• Toxicology
• Ecotoxicology

Background:

• Mercury is highly toxic, while selenium is an essential micronutrient.
• Selenium can complex with mercury, potentially mitigating its toxicity.
• Assessing mercury and selenium levels in fish is crucial for dietary risk assessment.

Purpose of the Study:

• To quantify mercury and selenium concentrations in fish tissues.
• To analyze the Se:Hg molar ratio and HBVSe as toxicological risk biomarkers.
• To evaluate the influence of trophic level on mercury exposure risk and the role of selenium in attenuating mercury toxicity.

Main Methods:

• Collected and analyzed 309 fish tissue samples for mercury and selenium concentrations.
• Calculated the Se:Hg molar ratio and HBVSe (Health-Based Value for Selenium) as biomarkers.
• Compared mercury and selenium levels against Brazilian safety limits for fish consumption.

Main Results:

• Mercury levels in planktivorous and carnivorous fish exceeded Brazilian safe consumption limits.
• Highest selenium concentrations were found in planktivorous fish, lowest in herbivores.
• 42% of fish samples (n=131) exhibited Se:Hg molar ratios >1 and positive HBVSe values, indicating potential toxicological risk.

Conclusions:

• Trophic level significantly influences mercury exposure risk from fish consumption.
• The Se:Hg ratio provides a more rigorous assessment of mercury exposure risk.
• Selenium can attenuate mercury toxicity, but species-specific safe thresholds are necessary.