Recent Epidemiological Studies on Methylmercury, Mercury and Selenium

Area of Science:

• Environmental Health
• Neuroscience
• Epidemiology

Background:

• Minamata disease highlights historical methylmercury dangers, though high-level contamination is now rare in Japan.
• Ongoing mercury discharge from natural and industrial sources, alongside mining activities, poses risks globally.
• Children are particularly susceptible to methylmercury's neurotoxic effects, even at low exposure levels.

Purpose of the Study:

• To provide a recent overview of epidemiological studies on methylmercury and mercury exposure.
• To highlight key challenges and research gaps in understanding methylmercury's health effects, especially in children.

Main Methods:

• Review of recent epidemiological studies published after the Minamata Convention on Mercury (2013).
• Analysis of findings related to exposure assessment, child developmental neurotoxicity, and long-term effects.
• Consideration of concurrent exposure models and potential mitigating factors.

Main Results:

• Increased publications on methylmercury/mercury exposure assessment since 2013.
• Child developmental neurotoxicity from prenatal methylmercury exposure is a critical issue, but precise assessment is challenging due to subtle effects.
• Unresolved questions remain regarding the persistence of IQ deficits and the impact of low-level postnatal exposure in birth cohort studies.
• The need for concurrent exposure models (including lead, PCBs, arsenic, pesticides) and consideration of antagonists (PUFAs, selenium) is emphasized due to very low methylmercury levels in developed countries.

Conclusions:

• Methylmercury's impact on child neurodevelopment requires further investigation, especially at low exposure levels.
• More human, animal, and molecular studies are essential to elucidate methylmercury toxicity mechanisms.