Over 90 per cent of proposed hydroelectric projects in Canada could expose local indigenous communities to high levels of neurotoxins, according to Harvard University researchers.
The Harvard University researchers found that the overwhelming majority of proposed Canadian hydroelectric projects are likely to increase concentrations of methylmercury in food webs near indigenous communities.
Methylmercury is a neurotoxin that is associated with increased risks of cardiovascular disease and neurodevelopmental delays among children. Pregnant women and children are particularly at risk from the health impacts of methylmercury.
It is formed when microbes convert naturally occurring mercury in soils after land is flooded, such as when dams are built for hydroelectric projects, the researchers explain. The potent methylmercury finds its way into the water and animals, magnifying as it moves up the food chain. On average, exposure to the toxin will double after the upstream is flooded.
The people at the highest risk of mercury exposure are those who eat locally caught wildlife nearly every day, namely the local indigenous communities whose diets tend to be rich in local fish, birds and marine mammals such as seals.
“For populations that relies heavily on locally caught food, the increase in exposure is drastic,” said Ryan Calder, one of the researchers involved in the study. “We see substantial fractions of this population whose pre-flooding methylmercury exposure is at or below regulatory thresholds and post-flooding are pushed way above them without mitigation measures.”
But unlike most human and ecological assessments of methymercury exposure, which are conducted only after the damage has been done, the Harvard University researchers also looked at how to mitigate the impacts of the proposed hydroelectric projects on local communities. One measure could be to remove the top layer of soil before flooding.
“This research opens the door to anticipating environmental impacts before the damage is done and moving forward with green energy alternatives in manner that does not impose an unfair burden on nearby indigenous communities,” said Elsie Sunderland, senior author of the study.
Image credit: Axel Drainville, flickr/Creative Commons