The paper builds on existing literature, highlighting current understanding and identifying unresolved issues about MeHg exposure, health effects, and risk assessment, and concludes with a consensus statement. Methylmercury is a potent toxin, bioaccumulated and concentrated through the aquatic food chain, placing at risk people, throughout the globe and across the socioeconomic spectrum, who consume predatory fish or for whom fish is a dietary mainstay. Methylmercury developmental neurotoxicity has constituted the basis for risk assessments and public health policies. Despite gaps in our knowledge on new bioindicators of exposure, factors that influence MeHg uptake and toxicity, toxicokinetics, neurologic and cardiovascular effects in adult populations, and the nutritional benefits and risks from the large number of marine and freshwater fish and fish-eating species, the panel concluded that to preserve human health, all efforts need to be made to reduce and eliminate sources of exposure.

Neurotoxic effects are known to occur with inhalation of manganese particulates, but very few data are available on exposure to Mn in water. We undertook a pilot study in a community in Québec (Canada) where naturally occurring high Mn levels ...

Background: Fish is considered protective for coronary heart disease (CHD), but mercury (Hg) intake from fish may counterbalance beneficial effects. Although neurotoxic effects of methylmercury (MeHg) are well established, cardiovascular effects are still debated. The objective of the present study was to evaluate blood pressure in relation to Hg exposure and fish consumption among a non-indigenous fish-eating population in the Brazilian Amazon. Methods: The study was conducted among 251 persons from six communities along the Tapajós River, a major tributary of the Amazon. Data was obtained for socio-demographic information, fish consumption, height and weight to determine body mass index (BMI), systolic and diastolic blood pressure, and Hg concentration in hair samples. Results: Results showed that overall, systolic and diastolic blood pressure, were relatively low (mean: 113.9 mmHg ± 14.6 and 73.7 mmHg ± 11.0). Blood pressure was significantly associated with hair total Hg (H-Hg), age, BMI and gender. No association was observed between fish consumption and blood pressure, although there were significant inter-community differences. Logistic regression analyses showed that the Odds Ratio (OR) for elevated systolic blood pressure (≥ 130 mmHg) with H-Hg ≥ 10 μg/g was 2.91 [1.26–7.28], taking into account age, BMI, smoking, gender and community. Conclusion: The findings of this preliminary study add further support for Hg cardiovascular toxicity.

Manganese is an essential element, but excessive manganese exposure has neurotoxic effects. To examine blood manganese levels in the general population with respect to sex, age, race/ethnicity, pregnancy and menauposal status, as well as levels of trace elements in blood. We used data from the National Health and Nutrition Examination Survey, a national survey of U.S. residents (n = 7720 participants, ages 1 to 80 years). General linear models and generalized additive models were used to examine the association between blood manganese concentration and participants’ characterisics, accounting for the complex survey design. Blood manganese levels ranged from 1.6 to 62.5 μg/L, with arithmetic means of 10.6 and 9.2 μg/L for women and men, respectively. The following characteristics were significantly associated with higher blood manganese levels: female sex, younger age, Asian origin, and being pregnant. In addition, there were non-linear relationships between blood manganese levels and cadmium, iron, lead, and mercury levels. The higher blood manganese levels observed among females suggest sex-related metabolic differences in the regulation of manganese, and elevated levels among pregnant women suggest an important role of manganese in reproduction. The present study supports the need to take into consideration age- and sex-related differences in blood manganese levels, as well as pregnancy status when examining manganese essentiality or toxicity.

This study examined the association between self-reported diabetes, fish consumption and serum levels of organochlorines in a First Nation community. One quarter of the 101 participants reported diabetes. Serum PCBs, but not p,p’-DDE, were positively correlated to consumption frequency of total fish, walleye and pike, but not trout. Reported diabetes was positively associated to p,p’-DDE and some PCB congeners. Odds Ratios (OR) for reported diabetes for those in the upper 75th percentile for serum p,p’-DDE compared to the others were 3.5 (95% CI 1–13.8) and 6.1 (95% CI 1.4–27.3) (weight wet and lipid-standardized values, respectively) and for total sum of PCBs: 4.91 (95% CI 1.4–19.0) and 5.51 (95% CI 1.3–24.1). For participants who were in the upper 50th percentile for trout and white fish intake, reported diabetes was respectively 6 and 4 times lower compared to the others. These findings support the hypothesis that environmental exposure to elevated p,p’-DDE and PCBs is associated with increased risk of diabetes. Consumption of trout and white fish may be beneficial to reduce risk.