Scientists back Inuit in efforts to limit mercury poisoning risk from Muskrat Falls hydro project

An almost two-week occupation at the site of a multibillon-dollar hydroelectric project in Labradoris winding downafter Newfoundland and Labrador Premier Dwight Ball vowed to make all future decisions "using science-based research."

That marks a significant victory for the Inuit, whoseprotests and hunger strikes were based on studiesout of Harvard University that warned the Muskrat Falls project would poisontheir food sources if the government didn't take steps to prevent methylmercury from being released into their waterways.

"The decisions that will be made, going forward, will not be at the whim of government," Todd Russell, the president of the NunatuKavut Community Council, said on Wednesday. "They will be made by science and it will incorporate the traditional knowledge of our people. This is a huge step forward."

• A look back at methylmercury concerns in Labrador
• Labrador leaders make 'significant' Muskrat Falls progress
• Muskrat Falls protesters 'fighting for land and food'

So how does a project aimed at providing a greener source of energy jeopardizeLabrador's fish, wildlife and people? Here's a breakdown of the science behind the methylmercury risk linked to the Muskrat Falls project.

What is methylmercury?

Methylmercury forms in naturewhenbacteria reacts with mercury in water, soilor plants, in a process called methylation.

Its levels increase as it moves up the food chain for example, from algaetoplankton to fish to people. Eating food from water with evenlow levels ofmethylmercurycan be dangerous.

"You could drink a swimming pool of this water every dayand it would not affect your health," Trevor Bell, a Memorial University of Newfoundland geographer and project leader on a study ofmethylmercuryrisks with the Muskrat Falls project.

"When youget to the top of [the food chain], the fish and the seals, that's 10 million times the concentration as in the water."

Why is it dangerous?

According to the U.S. National Library of Medicine,methylmercury poisoning can cause serious brain and spinal cord damage, resulting in blindness, growth problems, impaired mental functioning, birth defects and potentially cerebral palsy.

The worstexample of its effects are in Japan's MinamataBay,where morethan 1,000 people died and thousands more werewere sickenedby seafood from waters polluted by mercury from theChissoCorporation's chemical factory in the 1950s.

In Canada, First Nations people inGrassy Narrows, Ont., continue to suffer the effects of mercury poisoning fromReed Paper's chemical plant in the '60s and '70s.

How can a dam poison the water?

Muskrat Falls is not a chemical plant, and it won't be dumping mercury into Labrador's ecosystem.

It doesn't have to, because the mercury is already there.Some of it occurs naturally in soil, and some is deposited by precipitationfrom industrial emissions worldwide.

Nalcor, the provincial energy company behind the Churchill River hydroelectric project, wants to floodthe Muskrat Falls reservoir to construct its dam.

That could create the conditions for mercury to turn into methylmercury,because it would unleashcarbon from the soil and plant life, fuelling methylation.

That reservoir is just upstream from the LakeMelvillemarine estuary the Inuit's primary source of fishing and hunting.

Studiesled by Bell andconducted inconjunctionwiththe University Manitoba and scientists from Harvard University found the floodingcould elevatemethylmercury in Lake Melville far beyond what naturally occurs.

Nalcor's environmental assessment presumed themethylmercury would be diluted in the estuary, but theHarvard researchers found the mix offresh and salt waterwould prevent that from happening, and would evenacceleratethe biomagnification process.

"When fresh and salt water meet salinity increases as water deepens. This stratification allows fluffy organic matter that typically sinks to the bottom to reach a neutral buoyancy meaning it can't float up or down in the water column," explains aHarvard Gazette article summarizing the research.

"This layer, called marine snow, collects other small settling debris and concentrates it into a feeding zone for marine plankton."

What can be done?

In 2011, ajoint reviewpanelrecommended the best way to deal with the effects would be full vegetation clearing. It also recommendedNalcor and the federal government launch a study to determine thefeasibilityof clearing reservoirsin general of both vegetation and topsoil.

"If you remove that fuel, then you very much slow or eliminatethe conversion tomethylmercury," Bell said.

No study was ever launched andNalcorlater agreed to partially clear the vegetation.

In April 2016, the Harvard teamreleased more research, suggestingmethylmercurylevels could rise as much as 380 per cent if only partial clearing takes placein the reservoir.

"The bottom line is hundreds of Inuit individuals will be affected by this development," researcher Elsie Sunderland said at the time. "To the point that they exceed regulatory thresholds for exposure."

A win for science

Armed with this knowledge, protesters began occupying the reservoir last week to block the flooding.

"We're fighting for our land and our food," protesterPauline Williams told CBC News.

On Wednesday, the province and Indigenous leaders reached an agreementthat will create aspecial committee of scientists to explore ways to reduce methylmercury contamination, and open the door to possibly clearing the reservoir.

Bell said it's a win for grassroots democracy and science-based policy.

"The agreement is important for Labradorians and for Muskrat Falls,but has an impact beyond Labrador and nationwide on hydroelectric developments and evidence-base decision-making," Bell said.