How climate change is making the NWT’s Smoking Hills more acidic, toxic

Researchers in Calgary have discovered in the Northwest Territories what they believe is the most acidic natural water in the world.

Climate change is causing thawing and recession of permafrost from the Smoking Hills Formation – a process of land erosion. This is causing toxic metals and highly acidic solutions to leak into rivers, bays and potentially the Arctic Ocean.

Stephen Grasby, research scientist with the Geological Survey of Canada, visited In 2017 and 2023 the site, on the northern coast of the region, and the ponds surrounding the Smoking Hills were fascinated by the sheer scale of toxicity and acidity.

“It’s humbling to witness the forces of nature, for good and bad,” says Grasby. “Nature is producing the most toxic acidic water you will find anywhere – much worse than anything humans could create at an industrial site.”

The toxic metals that cause this natural phenomenon became trapped in iron sulfide minerals buried underground 85 million years ago, when Arctic Canada was ravaged by active volcanoes, known as pyrite or “fool’s gold.” Pyrite is known to absorb these metals and release them only when exposed to oxygen.

Previously, most of it was covered with rocky crust and permafrost.

However, Grasby says the meltdown has caused pyrite to become increasingly exposed to oxygen, releasing extreme heat and large amounts of metals into the waters around the Smoking Hills.

Between his two visits, Grasby observed a “dramatic change in the landscape” in terms of the number of bears.

The ponds had also turned black and looked closer to oil than water, with such high acidity that the team’s equipment struggled to accurately measure its pH level.

“This is the first time in my career I’ve seen that,” Grasby said. “Our pH meters were reading negative pH values, and they only go up to negative two, and if it’s more acidic than that, the meter can’t read it anymore.”

The temperature of the ground surrounding the water was also too hot to measure, as their instruments could only read temperatures up to 350 C. Grasby found evidence that suggested temperatures were more than three times higher.

“There are places where we found rocks that look exactly like the lava you see in Hawaii — it’s solidified lava,” Grasby said. “What this tells you is that the rocks got so hot that they melted, they flowed out and then hardened in the air. You need over 1,200 C (temperature) to melt those rocks.”

Known as paralava, the hot rocks lie just below the surface, creating a crème brulee effect, where simply walking on the ground exposes the hot layer below.

“We took a picture of the ground with the thermal camera, out of curiosity, and it says it’s 25 C. We took a step and stepped back a foot and took a picture of the same area now with the footprint, and the footprint is reading 350 C just inches down into the ground.”

The permafrost that protects the land from weather erosion is melting due to climate change, exacerbating the problem.

Elliot Skierszkan of Carleton University says that the melting of permafrost is not a new thing, but the study of its consequences has just begun.

“We clearly have evidence of a new consequence of permafrost thaw that has affected water quality,” said Skierszkan, who leads the field on geologic contaminants in groundwater. “This is 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 done about the formation.

As a result, potential environmentalThe effects are still unknown, and Grasby and Skierszkan are concerned about leaching of metals 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 downstream, pH levels increase, approaching their natural levels, but they can still harm the river ecosystem.

“River life is definitely a concern,” Skierszkan said. “Corrosion comes from precipitation of metals that form when the pH increases, but those precipitates can cover stream beds, so they can also cover the habitats where aquatic insects like to live, and it can also cover the stream beds where fish spawn.”

Some of the metals released, such as iron, can be beneficial to aquatic life in reasonable amounts.

Others are poisonous in any quantity, let alone the mass amounts measured by Grasby. For example, they measured levels of the metal cadmium nearly 7,000 times higher than safe drinking guidelines.

Both Grasby and Skierszkan believe more research is needed to truly understand the Smoking Hills and the effects of climate change on them.

“We’re just hoping that the findings will be useful to people who live in the area, but also inspire more research,” Grasby said. “It is important to understand what the acceleration of these processes might mean for otherwise pristine Arctic environments.”