Calgary researchers discovered in the Northwest Territories what they believe is some of the most acidic natural water in the world.
Climate change is causing thawing of the permafrost and slumping — a process of land erosion — from the Smoking Hills Formation. That’s leading to toxic metals and a highly acidic solution to leak into rivers, bays and potentially the Arctic Ocean.
Geological Survey of Canada research scientist Stephen Grasby visited the site on the territory’s north shore in 2017 as well as 2023, and was fascinated by the sheer scale of the toxicity and acidity in the ponds around the Smoking Hills.
“It’s humbling to see the powers of nature for good and bad,” Grasby says. “Nature is producing some of the most toxic acidic waters you would find anywhere — far worse than humans can ever make at an industrial site.”
The toxic metals causing this natural phenomenon were trapped in iron sulfide minerals buried underground known as pyrite, or “fool’s gold,” 85 million years ago when Arctic Canada was ravaged by active volcanism. Pyrite is known to absorb these metals and only releases them when exposed to oxygen.
Previously, most of it was covered by a rock layer and permafrost.
However, Grasby says slumping has led to a steady increase in the exposure of pyrite to oxygen, releasing extreme heat and large quantities of metals into the bodies of water around the Smoking Hills.
Between his two visits, Grasby noted a “dramatic change in the landscape” in terms of the number of slumps occurring.
The ponds had also turned black and looked closer to oil than water, with such high acidity that the team’s equipment struggled to precisely measure its pH level.
“It’s the first time in my career I’ve ever seen this,” said Grasby. “Our pH meters were reading negative pH values, and they only go down to about negative two, and if it’s more acidic than that, the meter just can’t read it anymore.”
The temperature of the ground surrounding the water was also too hot to measure, as their equipment could only read up to 350 C. Grasby found evidence that suggested the temperature was more than three times that.
“There’s places where we found rocks that look just like lava you would see in Hawaii — this solidified lava,” Grasby said. “That tells you that the rocks got hot enough that they melted, they flowed out of the outcrop and then hardened in the air again. You need [temperatures] over 1,200 C to melt those rocks.”
Known as paralava, the hot rocks lie just under the surface, creating a crème brûlée effect where simply walking on the ground exposes the hot layer underneath.
“We, just out of curiosity, took a picture of the ground with the thermal camera, and it says it’s 25 C. We took a step and moved a foot back and took a photo of the same area now with the footprint, and the footprint is reading 350 C just inches down into the ground.”
The permafrost protecting the ground from weather erosion is thawing because of climate change, compounding the issue even further.
Permafrost thawing is nothing new, says Carleton University’s Elliott Skierszkan, but the consequences of it are only just starting to be studied.
“We quite clearly have evidence of a new outcome of permafrost thaw that has impacted water quality,” said Skierszkan, who is leading the field with regards to geogenic contaminants in groundwater. “It’s a new issue that we need to develop our understanding of to help predict and manage water and aquatic ecosystems in the North.”
The Inuvialuit people have lived near the Smoking Hills for hundreds of years, but little research has been carried out about the formation.
As a result, the potential environmental effects are still unknown, and Grasby and Skierszkan are concerned about metals leaking into other bodies of water.
Grasby says some people in Alaska and northern Canada have reported rivers turning orange. They call it “rusting rivers,” he says.
As the metals flow farther downstream, the pH level increases, nearing its natural level, but they can still harm river ecosystems.
“The river life is definitely a concern,” Skierszkan said. “The rusting comes from precipitation of metals that form when that pH increases, but those precipitates can coat the stream beds, so they can coat habitats where aquatic insects like to live, and it can also coat those stream beds where fish spawn.”
Some of the metals being released, such as iron, can be beneficial for aquatic life in appropriate quantities.
Others are toxic in any quantity, let alone the extensive amounts that Grasby measured. For instance, he measured levels of metal cadmium about 7,000 times higher than safe drinking guidelines.
Grasby and Skierszkan both believe more research is needed to truly understand the Smoking Hills and the effects climate change is having on them.
“We’re just hoping the findings are useful for people who live in the region, but also motivate a lot more research,” Grasby said. “It’s important to understand what the acceleration of these processes might mean for an otherwise pristine Arctic environment.”
