A scientific paper published Wednesday by researchers at Harvard University says 11 other proposed hydroelectric sites in Canada would have even higher levels of methylmercury than Muskrat Falls in Labrador.

The paper, published in the journal Environmental Science & Technology, is based on research carried out between 2012 and 2015 on samples of organic material taken from the Lake Melville area, and country food eaten in the region.

A map from the Harvard study shows planned hydroprojects across the country, including one at Muskrat Falls, Labrador. (Harvard University)

The research involved hundreds of Inuit people living downstream of the controversial hydro project — in Happy Valley-Goose Bay, North West River and Rigolet — who provided hair samples for testing and answered questions about their daily diet.

The Harvard team concluded that, on average, exposure to methylmercury will double after flooding for the Muskrat Falls project, and that people who eat locally-caught wildlife nearly every day — especially river fish — are at highest risk.

It said projected increases are greatest in Rigolet, where people eat the most trout, seal, birds and other wildlife, with over half the women of childbearing age and young children projected to exceed levels approved by the United States Environmental Protection Agency.

Not just Labrador

Using its findings from Muskrat Falls, the team created a framework that it applied to 21 other proposed hydroelectric sites in Canada, all located within 100 kilometres of Indigenous communities.

It said more than half would have methylmercury levels even higher than at Muskrat Falls, which has a relatively small reservoir of 41 square kilometres.

The highest forecasted concentration was at Romaine 4 in Quebec, which includes plans for a flooded area of 144 square kilometres.

Researchers collected soil samples from Lake Melville, and talked to hundreds of people who live in communities upstream from Muskrat Falls. (CBC)

"While more research needs to be done on these other sites, our research shows that some hydroelectric projects are more green than others," Elsie Sunderland, professor of environmental science and engineering, and the study's senior author said in a news release.

"This research opens the door to screening these projects and identifying the ones where mitigation efforts, like removing the top layer of soil before an area is flooded, would be most effective."

The Harvard paper concluded that: "Without such mitigation strategies, our analysis shows hydroelectric development will have a disproportionate impact on Indigenous communities, affecting long-term neurocognitive function in children and with potential population level impacts on endocrine and cardiovascular health."

Dr. Elsie Sunderland from Harvard University's John A. Paulson School of Engineering and Applied Sciences is senior author of the study published Wednesday. (Twitter)

The paper builds on earlier research done by the Harvard lab, research that has been used to fuel protests against the Labrador project.

However, it is the first time the conclusions have been applied to other hydro projects, looking at potential risk across Canada.

Sunderland said in the past health risks from methylmercury exposure were "understood in retrospect, after the damage is done."

Methylmercury concerns are what drove protests about the Muskrat Falls project in Labrador and St. John's. (Paul Daly/Canadian Press)

The Nunatsiavut Government, which represents Inuit in Labrador, worked with the Harvard team.

Its leaders, along with other Indigenous groups, have allowed Nalcor Energy to begin raising water levels at Muskrat Falls, but only to what would be normal during spring runoff.

The Newfoundland and Labrador government has said water levels will be brought back down in the spring of 2017.

Hydro projects in the Harvard study with projected methylmercury levels above Muskrat Falls:

False Canyon (Liard, YT)

Middle Canyon (Liard, YT)

Detour Canyon (Pelly, YT)

Granite Canyon (Pelly, YT)

Slate Rapids (Pelly, YT)

Fraser Falls (Stewart, YT)

Romaine 1 (La Romaine, QC)

Romaine 2 (La Romaine, QC)

Romaine 3 (La Romaine, QC)

Romaine 4 (La Romaine, QC)

Gull Island (NL)

Other projects, proposed or under construction, with lower projected methylmercury levels: