McMaster researcher helps uncover rapid Arctic water pollution driven by climate change

“Thawing permafrost is rapidly transforming dozens of Arctic streams into acidic, metal-laden waterways, according to new research published today in Science . The study shows how thawing permafrost exposes sulphide minerals that react with oxygen and water — a process similar to what occurs in mining pollution. The reactions release acidity and heavy metals such as zinc, nickel, cadmium and aluminum into surrounding waters. These findings draw on decades of careful observation in one of the most remote regions on Earth. Sean Carey, professor in the School of Earth, Environment and Society and one of the co-authors of the study, has been working in the Yukon since the mid-1990s. His work has focused on building relationships with local and Indigenous communities and developing long-term monitoring sites to understand how northern water systems respond to environmental change. Data from the Tombstone Watershed Observatory, a long-running monitoring site in the Yukon supported by the CFI-MSI Global Water Futures Observatories program, made it possible for researchers to capture the changes as they unfolded. The team, which included PhD student Andras Szeitz, tracked shifts in water chemistry across multiple streams. While analyzing trace metals in the water, the team witnessed dramatic changes as they happened. “What shocked all of us was how quickly this happened. We expected changes over decades, but we watched pH levels crater toward highly acidic values and streams turn orange within a two-year period that started in 2023,” explains Elliott Skierszkan, assistant professor at Carleton University and lead author of the paper. In some cases, streams turned from clear to orange between daily observations. “It’s very rare in our type of work to see something change so quickly,” Carey says, adding that the scale of the changes is equally concerning. Rather than a single pollution source, as with a mine, these chemical reactions are occurring across hundreds of catchments in Yukon and Alaska simultaneously. “What’s striking is both the speed and the scale. Water quality in some of these catchments is deteriorating extremely quickly, and wherever the underlying geology contains sulphide minerals, we’re seeing this occur across entire regions,” says Matthew Lindsay, a professor at the University of Saskatchewan. This degrading water quality means streams can become highly acidic and unsuitable for aquatic life. Larger rivers may dilute some of these impacts, but the long-term consequences remain uncertain – particularly as metals move through ecosystems and follow various pathways. From the beginning, the research has been shaped by local concerns. A defining feature of Carey’s work is its close connection to Indigenous communities in the Yukon. “They told us, ‘We’re worried about the water,’” says Carey. “People know these changes are occurring, but they probably didn’t know they’re happening this fast and at more than one location.” Those concerns are now taking on new urgency. (Elliott Skierszkan, Carleton University) Many residents rely on local waterways for fishing, hunting and cultural practices, meaning changes to water quality can have ripple effects across food systems and ways of life. “This is about water security, food security — human security, really,” Carey says. Carey says these findings underscore something he has advocated throughout his career: the critical importance of sustained, long-term environmental monitoring. For years, maintaining Arctic observatories required constant effort and uncertain funding. The payoff, he says, is now clear. These datasets are becoming increasingly valuable — not just for understanding what is happening now, but for anticipating what comes next. “If it weren’t for these long-term investments, we simply wouldn’t have seen this happening,” Carey says. The post McMaster researcher helps uncover rapid Arctic water pollution driven by climate change appeared first on McMaster News .

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