Waste from mill worsening mercury contamination in river near Grassy Narrows: study

Industrial discharge from a paper mill in northern Ontario is exacerbating mercury contamination in a river system near a First Nation that has been plagued with mercury poisoning for decades, a new study suggests.

Industrial discharge from a paper mill in northern Ontario is exacerbating mercury contamination in a river system near a First Nation that has been plagued with mercury poisoning for decades, a new study suggests.

While the wastewater from the Dryden, Ont., mill doesn't contain mercury, the sulphate and organic matter in it contribute to the elevated production of methylmercury in the Wabigoon River, researchers from the University of Western Ontario said Thursday.

The levels of methylmercury -- the most toxic form of mercury -- in the river's fish may be twice as high as they would be without the mill discharge, they said.

"The mill operations today are making the methylmercury contamination problem worse in the Wabigoon River and delaying the recovery of mercury contamination and fish in that system," said Brian Branfireun, who led the research team.

The mill is upstream of the Grassy Narrows First Nation, a community of fewer than 1,000 people near Ontario's border with Manitoba.

The community's water was contaminated when the mill dumped 9,000 kilograms of mercury into the English-Wabigoon River system in the 1960s. The mill stopped using mercury in its industrial process in the 1970s, but mercury levels downstream of the plant haven't decreased since the 1980s.

One study estimated that 90 per cent of the Grassy Narrows population suffers from some degree of mercury poisoning. The heavy metal can be passed from mothers to babies they carry, making it a problem that spans generations.