A new study reported by the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) on its website revealed the potential health hazards of hydroelectric projects in Canada.
According to the study, over 90% of new Canadian hydroelectric power projects are likely to increase concentrations of methylmercury in the food chains on which nearby indigenous communities rely for sustenance.
Methylmercury is a more lethal form of the toxin mercury, which when ingested could cause heart disease and neurodevelopmental delays in children.
The hydropower plants are likely to increase methylmercury levels in the affected food chain as a result of the subsequent flooding that takes place when dams are built for these projects. The toxin then moves to the water and animals, and is magnified as it moves up the food chain. The toxin becomes a health hazard to the indigenous communities because their diets are rich in local fish, birds, and marine mammals such as seals.
Specifically, the study studied the effect of these power projects on Inuit communities based on their food consumption patterns, and the impact of existing plants on their ecosystems.
“For (a) population that relies heavily on locally caught food, the increase in exposure is drastic,” Ryan Calder, first author of the paper, said in the Harvard SEAS report.
“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. What our study
allows is time to consider mitigation measures that will reduce these potential exposures for the most vulnerable people,” he added.
Sunderland, a laboratory, also told Harvard SEAS, “Our research suggests that low impact hydroelectric projects are possible with careful site selection. Mitigation measures such as removing topsoil that provides the substrate for methylation in these ecosystems may need to be considered in areas where forecasted exposures are high.”
The study is a projection, rather than a retrospective of the effects of high methylmercury concentrations in potential hydroelectric power sites.
It is published in Environmental Science and Technology.
