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By Samhar Almomani, Publishing Associate: Researcher and Writer at Save the Water™ | October 11, 2025
Edited by Chase Day O'Donnell, Publishing Intern at Save the Water™ and Joshua Awolaye, Publishing Associate: Editor at Save the Water™
Degradation is affecting the Salmon River, one of the most remote and well-protected watersheds in North America. But in 2019, the river’s once-clear waters suddenly turned orange. They have remained turbid and discolored ever since. Scientists believe this rapid drop in water quality is linked to sulfide minerals breaking down as thawing permafrost exposes them. This decline is also seen in many nearby streams. Recent research shows the Salmon’s mainstem and most of its tributaries now contain metal levels that are toxic to aquatic life. This contamination may help explain the sharp drop in chum salmon returns. These species provide commercial income and food in a region already facing economic hardship.
Permafrost is a massive layer of frozen soil and sediment that has stored organic matter, nutrients, and pollutants for thousands of years. Industrial activity has added contaminants to these pollutants. As climate change warms the Arctic, this permafrost is thawing. This releases heavy metals and other toxins into streams and drinking water sources. Today, more than 75 rivers and streams across northern Alaska show acidic conditions with elevated trace metals.
Tests in the Salmon River basin reveal the severity of this shift. Nine out of ten tributaries exceeded the U.S. Environmental Protection Agency (EPA) toxicity thresholds for at least one metal. Such contamination poses a major threat to fish and wildlife populations that Indigenous and local communities depend on. This also endangers the safety of their drinking water.
Some tributaries of the Salmon River now run orange and cloudy from iron precipitates. Scientists attribute this growing crisis to sulfide mineral weathering. This is a chemical process in which minerals exposed by thawing permafrost react with oxygen and water. This process spreads rapidly across the Arctic as warming accelerates. This raises urgent concerns for ecosystems and communities alike.
Current metal levels in fish tissue are not considered immediately hazardous. However, the long-term changes in rivers raise serious health concerns for people who rely on these waters and fish. Raised levels of metals like iron, aluminum, zinc, and cadmium pose risks of bioaccumulation, drinking water exposure, and reduced fish hauls. Documented human health effects include:
Can We Reverse Degradation?
Unlike mining areas with acid drainage management, these Arctic watersheds have many potential contamination sources without infrastructure to contain them. Once sulfide minerals begin reacting after permafrost thaw, the process is effectively irreversible unless the ground refreezes. The study warns that similar risks could unfold across the Arctic. Researchers emphasize the need to help communities and land managers anticipate these impacts and prepare for future challenges. The influence of sulfide mineral degradation is already clear. This is true even in some of the most remote and pristine rivers. With that said, people are exploring some promising solutions in other places in the world. One example is the Whitehaven Restoration project that aims to reverse the effects of the water turning orange.