Elevated levels of lithium, rubidium and cesium have been detected in waters associated with the historic Kings Mountain Mine, west of Charlotte, North Carolina, raising questions about the potential impact on environmental and human health.
However, the study also suggests that the legacy lithium mine is unlikely to significantly contaminate surrounding waters with common pollutants like arsenic and lead.
The findings, published in the journal Science of The Total Environment, come from a team of researchers at Duke University's Nicholas School of the Environment.
The study sheds light on the potential water quality impacts of historical lithium mining and provides essential baseline data for assessing the effects of reopening lithium mines in the region.
"The world is increasingly relying on lithium for the green-energy transition, but previous studies on the environmental effects of hard-rock lithium mining show mixed results," Avner Vengosh, professor of environmental quality at Duke University's Nicholas School of the Environment, said in a statement.
"This study provides new, important data to clarify the possible environmental impacts."
Legacy of the Kings Mountain Mine
The rural Piedmont area, where the Kings Mountain Mine is located, was once the world's largest lithium-producing region.
Opened in the 1950s, the mine was abandoned in the 1980s when lithium sourcing shifted to more accessible deposits in South America.
The lithium at Kings Mountain exists in granite-like pegmatite rock, bound to a green-tinged mineral called spodumene.
To study potential contamination, researchers collected samples of pegmatite, waste rocks, tailings, groundwater from the mine and surface water from Kings Creek.
Baseline samples from nearby streams were also analyzed to provide context. Laboratory tests simulated how contaminants from the rocks might leach into the environment under natural conditions.
Key Findings
The study found that common regulated contaminants—including arsenic, lead, copper and nickel—were present at levels below drinking water and ecological standards set by the U.S. Environmental Protection Agency (EPA).
"We don't see any of those contaminants," Vengosh told Newsweek. "So, that's the good news."
However, the research highlighted elevated concentrations of lithium, rubidium and cesium in the mine site's waters—levels that are uncommon in natural waters and not federally regulated.
When asked about what the health impacts could be for people living near the mine, Vengosh said, "We don't know, to be honest," explaining that the EPA and other global health agencies don't currently regulate these elements, so little is known about their potentially harmful effects.
Vengosh's team is currently working to examine drinking water quality near the old mine, and though the findings are yet to be published, he divulged that "so far we don't see any evidence for the occurrence of either lithium or other regular contaminants in drinking water wells near and far from the mine."
Implications for Future Lithium Mining
While the findings provide some reassurance about historical mining, the researchers caution that active mining and processing could introduce new risks.
Lithium processing involves chemical treatments to separate lithium from spodumene, which may introduce additional contaminants.
"Excavating and crushing ore is just one aspect of lithium mining. Processing—which requires a chemical treatment to separate lithium from spodumene—may include additional chemicals that could potentially affect water quality," Gordon Williams, a Ph.D. student in Vengosh's lab, said in the statement.
For Vengosh, careful monitoring will be essential for future lithium mining projects in North Carolina and beyond. The Kings Mountain Mine itself is slated for reopening in the coming years.
"We need to check that our baselines are correct and that the water quality isn't being deteriorated," Vengosh said. "Parallel to that, we need to conduct studies to understand what the health implications are of having those elevated levels of lithium and other elements."
But as the transition to green energy becomes both urgent and unavoidable, the potential risks of lithium mining are, Vengosh believes, outweighed by the need to move away from fossil fuels and their traditional environmental impacts.
"For a place like North Carolina, the impacts are small relative to the legacy of coal mining," he said. "There's no comparison in terms of the potential environmental impact of coal mining."
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Reference
Williams, G. D. Z., Saltman, S., Wang, Z., Warren, D. M., Hill, R. C., & Vengosh, A. (2024). The potential water quality impacts of hard-rock lithium mining: Insights from a legacy pegmatite mine in North Carolina, USA. Science of The Total Environment, 956, 177281. https://doi.org/10.1016/j.scitotenv.2024.177281
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