Abrupt Onset and Persistent Downstream Effects of Acid Rock Drainage on Rivers Across Northwest Arctic Alaska
Evinger TG, O'Donnell JA, Carey MP, Koch JC, Baughman CA, Hill KR, Frei RJ, Poulin BA. 2026. Abrupt Onset and Persistent Downstream Effects of Acid Rock Drainage on Rivers Across Northwest Arctic Alaska. AGU Advances. 7(6)
Warming in the Arctic is accelerating permafrost thaw, leading to changes in the water quality of streams and rivers that provide important ecosystem services to rural communities. In Arctic Alaska, a growing concern is the increasing number of rivers affected by natural acid rock drainage, a process that occurs when certain minerals are exposed to air and water, releasing acid, sulfate, and a mixture of major and trace metals. Here, we examined the effects of acid rock drainage on river chemistry across six watersheds in Alaska's Brooks Range. Acid rock drainage inputs were extremely acidic, with concentrations of nickel, zinc, and cadmium similar to those observed in mine-impacted rivers outside the region. Acidic, metal-rich inputs to rivers raised metal levels downstream by up to 70 times, with the potential for long range transport (>100 km). We used long-term water quality records to constrain the timing of onset to 2019–2020, which coincided with warm, snowy conditions of the preceding winters. Collectively, our findings document the recent and abrupt onset of acid rock drainage that releases toxic metals to Arctic rivers, with implications for wildlife and humans.
- Type
- Journal Article
- Authors
- Evinger, Taylor; O'Donnell, Jonathan; Carey, Michael; Koch, Joshua; Baughman, Carson; Hill, Kenneth; Frei, Rebecca; Poulin, Brett