TORONTO - A report commissioned by the Ontario government and the Grassy Narrows First Nation says waterways in and around the community appear to have high mercury levels decades after they were polluted.
It also calls for a comprehensive evaluation of the health and diet of the people who live in the area.
Water around Grassy Narrows has been contaminated with mercury since a local paper mill dumped an estimated 10 tonnes of neurotoxins into the system between 1962 and 1970.
The report by Patricia Sellers, who is a University of North Carolina professor, reviewed all available work related to human and ecological health in connection with the Grassy Narrows First Nation and came up with 40 recommendations.
Among them, it called for a health and diet survey, and an evaluation and expansion of nutrition and food security programs for the northwestern Ontario First Nation.
The report also found that while there had been many studies on Grassy Narrows over the years, there was a lack of a coherent and co-ordinated research frame work.
"This piece-meal approach to studies in (the Asubpeeschoseewagong Netum Anishinabek First Nation) has lead to some confusion among some people (both within and outside ANA) trying to make sense of it all," the report said.
"Such a research framework needs to be rooted in the needs, culture and history of the people of ANA, and to be flexible enough to respond to changing needs."
Sellers found the data on sediment levels in waterways around the First Nation particularly significant.
In one case, the report noted that the mercury concentration in surface sediment in Ball Lake, which is close to Grassy Narrows, has been increasing, which means it is higher than what it was in the 1970s.
The report suggested that the increase could be best explained by accelerated erosion, transport downstream and deposition of upstream particles richer in mercury than those already there.
"That has implications, I think, for the long-term levels for mercury in the food web in those basins," Sellers said in an interview. "The data also suggests...that legacy mercury is being transported downstream from basin to basin over time."
Sellers said mercury levels around Grassy Narrows, and the way in which they have been sustained over time, was "concerning from a human health perspective and revealing from an ecological perspective."
The report also noted there is no ongoing surveillance program for children exposed to mercury prenatally.
Grassy Narrows Chief Roger Fobister Senior said the government ought to clean up the lasting effects of the toxins dumped into waterways around the First Nation.
"When we shared our land and water we expected it to be kept pristine, but they have failed and destroyed our culture as a result,"he said. "We want that mercury cleaned up. There is no way around it because it is a sacred trust to take care of our land."
Premier Kathleen Wynne said the report would be analysed and her government would continue to work with the community.
"There is more work that needs to be done," she said. "The scientists have said to us there are questions about how to actually do the cleanup because moving the sediment ... can actually cause further damage. So we have to be very careful that we work with the community on all of those issues."
The report was completed in December 2014 but was only presented to the community on Friday and released publicly on Monday.