Legacy Lithium Mines Taint NC Water Quality Study

Researchers find historic mining has impacted surface water, but not domestic wells

Published on Feb. 10, 2026

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A study led by Duke University researchers has found that while historic lithium mining and processing in North Carolina's Tin-Spodumene Belt has impacted surface water quality, it has not directly contaminated domestic well water in the surrounding communities. The researchers analyzed groundwater and stream samples, finding elevated levels of lithium, rubidium, and cesium that likely stem from the area's natural geology rather than mining activities. However, the study also identified an arsenic hotspot in local groundwater, which the researchers believe is caused by the interaction between pegmatite and mica schist rocks in the region.

Why it matters

As demand for lithium grows with the rise of renewable energy, mining companies are eyeing the large underground deposits in North Carolina. This study provides important insights into the potential water quality impacts of both historic and future lithium mining in the region, helping to inform decisions about mine siting and water resource management.

The details

The researchers collected 93 groundwater samples, mostly from domestic wells, and 99 stream samples from inside and around the Tin-Spodumene Belt over a three-year period. They found no direct evidence of impacts on domestic well water from historic lithium mining and processing, but did find that streams near legacy mining and processing sites have relatively high levels of lithium and rubidium, likely stemming from interactions between water and gypsum, a material found in lithium processing waste. The team also identified an arsenic hotspot in local groundwater, which they believe is caused by the interaction between pegmatite and mica schist rocks in the region.

  • The study was published on December 2, 2025.
  • The research was conducted over a three-year period.

The players

Avner Vengosh

Distinguished Professor and Nicholas Chair of Environmental Quality at Duke University's Nicholas School of the Environment, who led the research team.

Gordon Williams

The study's first author and a Ph.D. student in the Vengosh Lab.

North Carolina Water Resources Research Institute (WRRI)

The organization that provided funding for the study.

Duke University Climate Research Innovation Seed Program (CRISP)

The organization that provided additional funding for the study.

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What they’re saying

“Our goal was to understand whether legacy mining and processing has affected the quality and chemical makeup of ground and surface water in and around the mines and through the Tin-Spodumene Belt. This research serves to keep surrounding communities informed about the potential water quality impacts of legacy mining operations.”

— Avner Vengosh, Distinguished Professor and Nicholas Chair of Environmental Quality at Duke University's Nicholas School of the Environment

“Finding lithium in your well water doesn't mean that you're being contaminated. It means that you live in an area with the same type of rocks that lithium is found in. If you live in an area with pegmatite — regardless of whether lithium mining is occurring — the groundwater naturally will have relatively higher lithium than it will in an area that does not have pegmatite.”

— Avner Vengosh, Distinguished Professor and Nicholas Chair of Environmental Quality at Duke University's Nicholas School of the Environment

“Mine siting should involve a detailed investigation of the underlying geology and its potential to impact water quality. If mica schist co-occurs with pegmatite, then that's a potential recipe for water quality impacts from arsenic.”

— Gordon Williams, Ph.D. student in the Vengosh Lab

What’s next

Residents with affected wells are in the process of switching to municipal water, according to the research team. The study findings could also inform decisions involving the placement of new lithium mines in the region.

The takeaway

This study highlights the importance of understanding the underlying geology when evaluating the potential water quality impacts of both historic and future mining operations. While the researchers found no direct evidence of domestic well contamination from legacy lithium mining, the identification of an arsenic hotspot underscores the need for comprehensive water quality assessments before siting new mines.