Published: April 7, 2010

By: Mike Barber, Canwest News Service

As members of Ontario First Nations descended on Toronto Tuesday to mark the 40th anniversary of the confirmation of mercury poisoning in their communities, a Japanese study, released for the first time in English, said exposure to "safe" levels of mercury over a long period of time has led to dozens of cases of mercury poisoning in the two Ontario communities.

Members of the Grassy Narrows and Wabaseemoong First Nations, also called on the federal and provincial governments to re-examine what they say are clear cases of the disease, persisting decades after their rivers — which for centuries had been their prime source of food — were deemed safe.

The mercury poisoning dates back to 1970, when excessive levels of the toxin — as well as such symptoms as vision loss, chronic pain and tremors — were recorded in many residents of Grassy Narrows and Wabaseemoong, about 90 kilometres northeast of Kenora, Ont. Residents found to have the illness were compensated in the 1980s by the Mercury Disability Board, enacted by the federal and provincial governments, as well as by the pulp mill deemed responsible for dumping more than 9,000 kilograms of mercury into the Wabigoon River between 1962 and 1970.

But research performed in 2004 by Masazumi Harada, a scientist who helped uncover the first widely known instance of mercury poisoning in Minamata, Japan, in the 1950s, suggested that many people born since the river was found to be safe are showing signs of the illness, and those whose symptoms were minor 40 years ago have worsened.

Of the 187 people tested, there were 14 cases of mental retardation, nine cases of mental deficiency and three cases of muscular dystrophy. Seven children had cerebral palsy, and another seven showed signs of intellectual developmental delay. Eighty-nine per cent of people who had tested below the level of mercury contamination in 1975 were found to have more severe symptoms 30 years later.

All told, Harada estimated that about four out of every five people tested showed at least minor cases of mercury poisoning, despite no one having more than the 50 parts per million of mercury in their bodies, which is considered the highest acceptable limit by Health Canada.

The study concluded it was possible to contract mercury poisoning "even under the safety guideline if they keep eating contaminated fish for a long period of time," and that pregnant women are at particular risk of passing the condition down to their children.

Seventy-seven residents who showed poisoning symptoms had previously been denied compensation from the Mercury Disability Board. "Our research implies there are many patients still suffering that have not been acknowledged yet," Harada wrote in the report.

Ontario Premier Dalton McGuinty told reporters in Peterborough, Ont., on Tuesday that while the province considers mercury levels to be under control, he has not yet read the report.

"I guess the good news is that we are smart enough as a society to no longer poison our lakes and our streams and our rivers in the way we did in the 1960s and 1970s," said McGuinty.

A spokesman form the Ontario Ministry of Aboriginal Affairs confirmed that the department was reviewing the study.

"We take the health of all Ontarians seriously," said Greg Flood in an e-mail. "As such we want to give this report the proper review and research once we receive it, and are looking forward to doing so."

Health Canada also said it would consider the report, but could not offer comment on its content yet. However, spokeswoman Christelle Legault confirmed that the department was working on a new set of guidelines for acceptable levels of mercury in "the most vulnerable groups — pregnant women, women of childbearing age and children."

Angus Toulouse, the Assembly of First Nations regional chief for Ontario, said that "acknowledging mercury poisoning in Grassy Narrows is a starting point" for the government. Further, he said Harada's study suggests the Health Canada should strengthen its mercury guidelines, and that the long-term effects of the contamination should warrant permanent monitoring at Grassy Narrows.

"We need the whole government to account for their actions and their inactions," he said. "It's been around for 40 years, and they can't be allowed to turn their backs on a community that's been physically, emotionally, and economically harmed."