A new study has found that warming temperatures are driving a significant increase in copper, zinc, and sulfate levels in Colorado mountain streams affected by acid rock drainage. Over the past three decades, concentrations of these metals have doubled in alpine streams, posing a threat to ecosystems, downstream water quality, and mining remediation efforts.
The study, published in Water Resources Research, linked the rise in acidity and metals to climate change, with lead author Andrew Manning stating, “Heavy metals are a real challenge for ecosystems. Some are quite toxic. We are seeing regional, statistically significant trends in copper and zinc, two key metals that are commonly a problem in Colorado.”
The research focused on 22 headwater streams in 17 watersheds above 3,000 meters elevation, combining pristine areas with those historically mined but left untouched for decades. The findings revealed that the warming and drying of mountains due to climate change are accelerating sulfide weathering in bedrock, releasing metals into groundwater and ultimately into surface streams.
Manning highlighted the importance of understanding the impact on water quality downstream, as some mountain communities rely on these mineralized streams for their water supply. Additionally, the findings could inform decisions on remediation efforts and tourism initiatives in the affected areas.
While Colorado’s watersheds are particularly affected due to their high sulfide content, the study suggests a global pattern of rising sulfate concentrations in mountain streams. This research provides a crucial link between warming temperatures and increased metal levels, emphasizing the urgent need to address climate change to protect vital water resources.
