Hair Mercury Levels in Six Iranian Sub-populations for Estimation of Methylmercury Exposure: A Mini-review

Mercury is widespread and persistent in the environment. One organic form of mercury, Methylmercury (MeHg), can accumulate in the food chain in aquatic ecosystems and lead to high concentrations of MeHg in fish, which, when consumed by humans, can result in an increased risk of adverse effects. Currently, the Joint FAO/WHO Expert Committee on Food Additives (JECFA) has established provisional tolerable weekly intakes (PTWIs) for total mercury at 5 µg/kg body weight and for methylmercury at 1.6 µg/kg body weight. Mercury concentration in blood or hair has been widely used for estimation of methylmercury exposure. In this review article, we calculated methylmercury exposure from hair mercury levels among six subpopulations (i.e. students, dentists, dental nurses, women with amalgam fillings, pregnant women in Mahshahr, and Women of a port town, Mahshahr, Iran). Some of the experiments had been performed by this group in previous years. The mean exposure level (µg/kg bw/day) in three Iranian groups (dentists, pregnant women, and women in Mahshahr) was higher than RfD and PTWIs. As people are exposed to methylmercury mainly through their diet, especially from fish and other marine species, pregnant women should reduce fish consumption, especially predatory fish, and dentists should use preventive measures (like masks and gloves).