The Inuit community of Inukjuak in Canada is in the process of being fully supplied with hydroelectricity from a 7.5 MW run-of-river hydroelectric project being built on the Innuksuac River by the Pituvik Landholding Corp. and its partner Innergex Renewable Energy.
The dam, which is near Hudson’s Bay, is one of the first in the world to be erected directly on permafrost. In addition, the project’s power plant will be supplied by the flow of the river, rather than depending on an artificial reservoir that requires flooding a large area.
However, creating a hydraulic funnel for the dam will require flooding some of the land upstream of the generating station. Concerns are that contaminants, including mercury and hydrocarbons stored in the permafrost, could be released into the environment and transported by the river.
In order to measure the extent of the potential effects of these contaminants, Professor Marc Amyot and his research team from the Department of Biological Sciences at the Université de Montréal are studying and characterizing the environment over a number of years to determine if there is degradation of the permafrost.
In particular, the researchers plan to pay particular attention to the methylation of mercury by microorganisms in the river.
They describe mercury methylation as a natural biological process that results in the production of a highly toxic compound, methylmercury, which accumulates in living tissues and increases in concentration up the food chain from aquatic insects to fish to other organisms that feed on it, including humans.
The research project also includes studying possible effects of hydroelectric dams located on Aboriginal territory on the Saint-Maurice and Romaine rivers.
The research project was co-constructed by Hydro-Québec and Innavik Hydro, as well as with the Inuit communities of Inukjuak, Innu of Ekuanitshit and Atikamekw of Wemotaci. It received C$1.9 million ($1.48 million) in support from the Alliance grant program of the Natural Sciences and Engineering Research Council of Canada.
The Saint-Maurice River has been used for decades to dredge timber. The combination of logging carried out near the river and intense forest fires that have occurred in the past may have led to an increase in mercury inputs to the river. The university researchers aim to assess over 300 km of river, the combined impact of 10 hydroelectric dams and disturbances to the landscape, on the mercury contamination of sediments, water and aquatic organisms.
As for the Romaine River, the research project there began in 2016 and involves four hydroelectric dams.
First results indicated high concentrations of methylmercury in the water near these dams. The researchers said that one surprise was that peaks of the contaminant had been observed as early as June rather than at the end of the summer season. Part of the project is intended to study the mechanisms related to the methylation of mercury under the ice, in winter.
