Fetuses, newborns and infants are most at risk for mercury exposure, and a sampling of newborns in the Lake Superior basin showed 8 percent of them testing above safe levels.

Mercury in humans is often from eating contaminated fish. Photo: Lake Superior State University

The study, conducted by the Minnesota Department of Health from 2008 to 2010, tested 1,465 newborns living in Michigan, Wisconsin and Minnesota for mercury. The 8 percent testing above safe levels had methylmercury in them, the kind from fish.

Even small amounts of mercury can hurt infants’ developing brain and nervous system.

Babies born in warm months were more likely to have higher levels, which, when coupled with the methymercury findings, suggest that fish consumption is the culprit.

Mercury can easily pass from a mother to her unborn child through the placenta.

The study is the first to look at mercury in newborns, so it’s hard to tell whether these levels are similar to those of general population.

Newborns that tested above EPA established mercury limits were broken down by state:

• No Michigan newborns
• 3 percent of Wisconsin newborns
• 10 percent of Minnesota newborns

Minnesotans report eating more locally caught fish, which could explain this discrepancy.

Researchers plan to use the findings to bolster fish consumption outreach to pregnant women.