Methylmercury levels downstream from Muskrat Falls concern researcher

·3 min read

It’s been just over a year since Nalcor Energy impounded the reservoir at Muskrat Falls.

How much methylmercury that would release into the water downstream and subsequently the impact it would have on the food chain in central Labrador has been the topic of much debate over the years, and that debate is still going on.

Ryan Calder, an assistant professor of environmental health and policy in the department of population health science at Virginia Tech, and the lead author of the 2016 Harvard paper "Future Impacts of Hydroelectric Power Development on Methylmercury Exposures of Canadian Indigenous Communities," took to social media recently to express his concern over the methylmercury readings for the first year following impoundment.

Calder said the increased levels showing at a station downstream from Muskrat Falls, N5, are more in line with what his group at Harvard estimated, and exceed the projections made on behalf of Nalcor Energy. He said he wishes they were wrong in their predictions, but based on what he’s seen so far it doesn’t appear to be so.

“Nalcor and the government of Newfoundland claimed that there was no possibility for risk to people or the environment, spent years claiming up and down there was nothing to worry about, and now monitoring is coming out showing that the peak levels are still increasing and are within the range that was forecasted,” he said.

Data from the last four years available online shows that the recorded levels in the water exceeded the Nalcor predicted peak of 0.1 namograms per litre a couple times in the last year and does show an increased overall level of methylmercury.

Calder said it’s common for levels to increase in the first year after impoundment and stay higher for a few years before levelling off, but any increase corresponds to an increase in risk.

“It’s known that when you flood a reservoir there are increased methylmercury levels. Nalcor doesn't deny that creation of the reservoir accelerates the production of methylmercury. They accept that there are impacts on water, they accept that people eat the fish, but they don’t accept there’s any risk to the people and that’s logically inconsistent.”

It’s too early at this point to assess any risk to people, he said, and that would require more data on methylmercury in fish, which has not been released yet for 2019, but increased methylmercury levels in the water are the first signal.

When asked by SaltWire Network about the levels, Nalcor Energy said the measured values in water are very similar to those predicted and are within safe limits.

James McCarthy, senior associate biologist with Wood, the firm that handles the monitoring for Nalcor, said he doesn’t see anything in the levels that would cause concern from a human health perspective.

“Ultimately, it’s the fish concentration that matters, that’s the interaction with people. Even though water is an early indication it’s really the fish that matter most to people. We just finished the sampling for 2019, so that’s a full year of flooding, but had three years of head pond formation, and we’ve seen nothing really in the fish.”

McCarthy said the increased levels are in line with projections made for Nalcor in 2018, which did differ from lower predictions in previous years, and so far everything appears to be on track.

The Department of Environment, Climate Change and Municipalities told SaltWire Network methylmercury levels are below the Canadian Council of Ministers of the Environment (CCME) guidelines for aquatic life and at no time have levels presented a risk to public health.

Evan Careen, Local Journalism Initiative Reporter, The Telegram