The mercury poisoning Grassy Narrows First Nation was supposed to go away over time. A new study reveals why it’s worse than it should be

For decades the people of Grassy Narrows First Nation were told the toxic mercury dumped in the river by a paper mill in the 1960s would eventually go away.
As the neurotoxin marched its way up the food chain, poisoning the fish that the people ate, they took cold comfort in the government’s assurances that the mercury threat would diminish over time.
They were alarmed to find out just a few weeks ago that current sulphate emissions from the mill are exacerbating the impact of the old mercury still in the river system.
Sulphate-infused industrial wastewater discharged by the Dryden mill into the Wabigoon River is speeding up the bacterial process that creates a dangerous form of mercury, making the already existing contamination “worse than it would otherwise be,” says a new study written for Grassy Narrows leadership, funded in part by the province, and obtained by the Star.
The new findings help explain why mercury contamination levels remain higher than scientists have thought they should be after so many years since the original industrial dumping upstream.
“This has made our suffering worse and it has to stop. We need justice, not more poisoning,” said Chief Rudy Turtle of Grassy Narrows.
The research was conducted by Masters of Science student Eric Grimm and led by Western University professor and mercury expert Dr. Brian Branfireun.
Branfireun estimates that the methylmercury levels in Wabigoon River water and fish are likely at least two times as high as they would be if not for the effluent.
“These results clearly indicate that the Dryden Mill industrial wastewater that is discharged to the Wabigoon River is making the mercury contamination in fish worse than it would be if it were not present,” concludes the study.
The mercury poisoning of the residents of Grassy Narrows and the fish they eat has been well documented after the old Dryden pulp and paper mill, operated then by Reed Paper, dumped 10 tonnes of mercury into the Wabigoon-English River system between 1962 and 1970. The dumping took place upstream from Grassy Narrows and nearby Wabaseemoong (Whitedog) Independent Nations.
The mill is now owned by First Quality Group and operates under the name Dryden Fibre Canada.
Dryden Fibre Canada (DFC) declined to answer questions from the Star, and said they had not yet seen, nor been briefed, on Branfireun’s report. DFC was sent a copy of the report by lawyers representing Grassy Narrows on May 17.
The study is based on samples taken in the summer of 2023 as well as in 2019, when the mill was owned by Domtar. In a statement, a Domtar spokesperson said it complied with the government’s limits on effluent discharge and never used mercury.
“The assumption linking sulphate and mercury methylation at the Dryden Mill is new to us,” the spokesperson said, noting the source of the contamination is legacy mercury-bearing sediments as confirmed by various studies, including one by Branfireun.
After this article was published, a spokesperson from the provincial Ministry of the Environment, Conservation and Parks said in a statement that the Ontario government is reviewing the study’s findings.
The spokesperson said the province will work with the mill’s owner as well as the English and Wabigoon Rivers Remediation Panel, made up of local indigenous leaders and government officials, “to determine how this information will assist in the development of a remediation plan for the rivers.”
The study will also be shared with a team of mercury remediation experts, who have been funded by the panel to develop a model of the river system, the spokesperson said.
The federal government did not respond to questions sent by the Star.
A legacy of people poisoned by the river
Mercury has not been used at the Dryden mill for decades. In the 1960s, the chemical was used in the process of bleaching pulp for paper.
The metal does not break down in the environment and can build up in living things, known as bioaccumulation, “inflicting increasing levels of risk on higher order species,” according to a federal government website.
Bacteria that thrive in wet, low-oxygen environments such as lake bottoms turn mercury into its most toxic form, methylmercury.
The methylmercury migrates up the food chain to fish and then the locals who eat the fish. Among the people of Grassy Narrows, the mercury has caused tremors, loss of muscle co-ordination, slurred speech and tunnel vision.
Since the 1980s, the Dryden mill’s emissions have contained sulphate, according to historical data seen by the researchers. When sulphate mixes with organic waste, which is also emitted by the mill, the ingredients fuel the process that forms methylmercury. The river does not naturally contain high sulphate levels, according to the study.
“These results are shocking, but not unexpected because existing science has pointed to this for decades,” said Branfireun, explaining that it has been understood by scientists that sulphate can interact with mercury in this way. “We now know with confidence that ongoing industrial pollution from the Dryden mill has made the mercury problem in the Wabigoon River much worse than it would have been if care had been taken after the initial discharge of mercury to protect the environment and the people who rely on it.”
“That is the real mechanism that’s actually causing the mercury problem in the fish in the river. Hands down. One hundred per cent. For sure,” said Branfireun.
If the mill stopped discharging sulphate, there would be a significant reduction of the harmful chemicals in the water and fish, he said.
“​​It’s frustrating to think that [removing sulphate from the water] is an actionable step that would have an immediate effect of reducing the amount of methylmercury in the environment.”
Though scientists have long suspected that old mercury still contaminates the land on or near the mill property — a 2017 Star investigation found mercury-contaminated soil in the ground behind the mill — this new study focuses on sulphate’s impact on mercury already in the river system.
The findings of Branfireun’s study are “profoundly important,” says Miriam Diamond, an environmental scientist at the University of Toronto who is not involved in the new study.
“There is no doubt about the effects that this wastewater is having on the mercury methylation process and I am encouraged that this science informs a way to address this egregious situation in the Wabigoon River and Grassy Narrows.” 
Last year, an intergenerational study found the industrial waste pollution contributed to the community’s youth attempting suicide at a rate three times that of other First Nations in Canada.
“The government must act quickly to make sure that no more harm comes to our people because of that mill and from other industries. We cannot bear any more impacts from pollution,” said Chief Turtle.
Editor’s note – May 23, 2024: This article has been updated to include the Ontario government’s response to the new study.