Why are rivers in Alaska turning orange?

Alaska’s rivers are turning orange and acidic due to the release of toxic metals such as iron, zinc, copper, nickel, and lead.  

Recent Highlights:

• This phenomenon is caused by permafrost thawing, a process where the ice within the permafrost melts, exposing water and soil.
• Permafrost is ground that remains frozen at 32°F (0°C) or colder for at least two years, characterized by its cold, dark, and oxygen-deprived conditions that preserve biological materials for many years.