Overview

• The analysis of the Salmon River finds dissolved metals and turbidity at levels that exceed U.S. EPA thresholds for aquatic life.
• Thaw lets water and oxygen oxidize sulfide minerals, generating sulfuric acid that mobilizes iron, cadmium and aluminum into the water.
• Cadmium is accumulating in fish organs while iron-driven turbidity reduces light and suffocates insect larvae that support salmon and other fish.
• The changes threaten chum salmon spawning habitat and indirectly jeopardize Indigenous subsistence fisheries in northern Alaska.
• Authors describe a process that mimics acid mine drainage yet arises naturally from permafrost loss, cautioning it may persist without permafrost recovery.