The following story was reported by the New England Center for Investigative Reporting, an independent, nonprofit news center that produces journalism and conducts investigative reporting workshops to train a new generation of journalists.
Mercury emissions from major Massachusetts sources have declined by 90 percent over the past two decades, but mercury levels in the state's freshwater fish hold stubbornly high, with many species too contaminated for pregnant women and children to eat.
The inability to reduce mercury in fish to safe eating levels troubles environment and health officials -- and added to that concern is growing evidence that some freshwater fish in similar northern latitudes, from the Great Lakes to Scandinavia, appear to have increasing mercury levels after years of decline. The New England Center for Investigative Reporting found six studies in the past decade that point to increasing mercury levels in freshwater fish.
"We need to figure out what is going on,'' said Michael S. Hutcheson, former head of air and water toxics for the Massachusetts Department of Environmental Protection who retired last month. Reducing emissions in Massachusetts certainly helped -- some freshwater fish near closed incinerators and other mercury sources showed a 44 percent decline in mercury levels -- but the difficulty in getting further reductions speaks to a more complex problem, he said.
Large numbers of people fish the state's lakes, ponds and rivers -- 172,800 freshwater fish licenses were issued in the past year, according to Marion Larson from the Massachusetts Division of Fisheries & Wildlife. But it is unknown exactly how frequently fishermen -- or families -- eat catch that might be contaminated.
On Boston's Jamaica Pond one recent sunny afternoon, Shu Bao Chen of Boston tied bait to a hook as one of his two young girls dangled a fishing pole over the still water. He said he was unaware of the state's blanket advisory that no children under 12 and no women of childbearing years should eat any fish from freshwater bodies in Massachusetts.
We come, "Sundays and Saturdays, when he has time,'' said Emily Chen, 13, translating for her father. The family came to Boston from China about five years ago and fish on the pond year-round. When asked what the family fishes for, Emily said "dinner."