Assessment of methylmercury exposure in Wisconsin

Between January 2004 and June 2005 the Wisconsin Department of Health and Family Services recruited more than 2000 adults for a methylmercury (MeHg) exposure assessment study. Study participants, including 978 men and 1050 women who ranged in age from 18 to 92 years, completed a fish consumption and advisory awareness survey and provided hair samples for mercury analysis. Fish intake estimates ranged from 0 to 60 meals/month (mean 7.7). Hair mercury levels ranged from 0.012 to 15.2 μg/g and were positively correlated with monthly fish meals. Despite reporting similar fish consumption rates, men tended to have higher hair mercury levels than women. Mercury levels exceeded 1 μg/g in 29% of the men and 13% of the women and increased with age. Approximately, half of the study volunteers were licensed anglers and 77% were familiar with Wisconsin's sportfish consumption advisory. Among consumers of sport-caught fish, 37% of the men and 18% of the women had a hair mercury concentration above 1 μg/g. These findings suggest that exposure to MeHg is widespread and that men may be a previously unrecognized high risk population.