Study Finds No Impacts to Household Well Water from Historic N.C. Lithium Mining

The researchers did find some impacts to stream water. Their results could inform the location of future mining operations

This is a summary of a story that originally appeared on the Nicholas School of the Environment website.

Duke researchers found no evidence of impacts to domestic well water from legacy, or historic, lithium mining in North Carolina. Used in products like rechargeable batteries, lithium is a silvery metal found in granite-like rock called pegmatite that used to be mined in North Carolina around the Charlotte area.

The researchers analyzed groundwater and stream water near two former lithium mines and processing facilities, where lithium was converted into usable material. They reported their results in Environmental Science & Technology.

The team found the pegmatite that naturally occurs in the area primarily affected the chemical makeup of groundwater. Specifically, their water samples revealed relatively high levels of lithium compared to average levels in North Carolina groundwater.

“Finding high lithium in well water in an area of lithium-rich rocks does mean that the water is contaminated from lithium mining — the groundwater has naturally relatively higher lithium than in other areas with different rocks,” said Avner Vengosh, Distinguished Professor and Nicholas Chair of Environmental Quality at the Nicholas School of the Environment, who oversaw the research.

By contrast, legacy lithium mining and processing probably contributed to high levels of lithium measured in stream samples collected near historic mining operations. However, those effects dissipated with distance from the sites.

The researchers also investigated why arsenic, a potent neurotoxin, has contaminated a previously identified cluster of neighborhood wells in Gaston and Lincoln counties. They suggested that interactions between groundwater and the underlying geology cause arsenic to leach out of rocks that naturally contain the chemical.

The research could inform preferable siting of new lithium mines.

“Mine siting should involve a detailed investigation of the underlying geology and its potential to impact water quality,” said Gordon Williams, first author on the paper and a Ph.D. student in the Vengosh Lab.

Learn more about this mining impact research in the full story on the Nicholas School of the Environment news site.