The Arctic’s rivers are turning a vibrant shade of orange, which scientists have attributed to thawing permafrost from—you guessed it—rising temperatures. Here’s the latest in this depressing saga: The rivers are now spreading plumes of metal and acid far downstream.

An analysis of six watersheds in Alaska’s Brooks Range revealed that the tributaries and seeps feeding into the park’s rivers are extremely acidic and metallic, with levels comparable—and sometimes even higher—than water drainage from rivers located near metal mines. While the rivers’ main waterstems weren’t as acidic, the region’s drainage system has been transporting contaminated water over 60 miles (100 kilometers) downstream. As the tributaries and seeps dump more water into the river, metal concentrations can increase by roughly 70 times compared to their initial entry. The findings were published yesterday in AGU Advances.