It’s hard to know what to think of the recent excitement over lithium in southern Arkansas.

On the one hand, south Arkansas needs an economic boost, and the world needs more lithium if we’re to transition from fossil fuels to renewables like wind and solar. On the other hand, the costs of lithium extraction in Arkansas are unknown because the technology being used is so new.

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Traditional lithium mining is dirty and energy intensive, but companies drilling for lithium-rich brine in south Arkansas, including ExxonMobil, say they have a better way: so-called direct lithium extraction, or DLE. But there are many questions about its viability when deployed at scale, as well as possible environmental consequences.

Mother Jones has a story this week by freelancer Boyce Uphold that explores those unknowns in depth. (It was originally published by the online magazine Yale Environment 360.) Uphold writes:

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But questions remain about DLE’s impacts, which have not been closely studied in Arkansas. How much water will these projects consume? Some scientists have expressed concerns that DLE might be more water-intensive than its promoters suggest. And what happens with DLE’s wastes, which can include some of the same toxins left behind in evaporative ponds? Much of the lithium mining companies’ data is proprietary, hindering research efforts, and pollution from existing brine-extraction industries that target bromine has raised questions about Arkansas agencies’ oversight. 

Arkansas has much to offer the industry. The subterranean brines in the Smackover Formation — a geologic formation that arcs from Texas to Florida and is centered on south Arkansas — are richer in lithium and less acidic than those in other parts of the country. The state has plenty of water, unlike some lithium drilling sites in the American West, which will be key in the extraction process. Arkansas also has plentiful drilling infrastructure, due to decades of drilling for oil and bromine, another element found in brine. That both lowers costs and means companies won’t be despoiling as much undeveloped land.

But Arkansas has a poor track record of regulating politically powerful industries. And, Uphold writes, experts in the field say it’s hard to assess the potential impact of DLE in part because “much information comes from the industry itself.”

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Companies will likely use “reinjection wells” to push brine back into the ground after the lithium has been extracted. That should reduce environmental impacts but it raises concerns of its own, Uphold reports:

But, studies suggest that the Smackover Formation is connected with the freshwater aquifer that lies closer to the surface, a kind of connectivity that The Nature Conservancy, in its 2022 report, suggested should be analyzed.

Daniel Larsen, a hydrogeologist at the University of Memphis, noted that in a properly designed system, damaging impacts on surrounding waters would be unlikely. But he said errors in construction or operation, as well as natural disasters, “could release fluids at the surface and damage water quality in wetlands, streams and lakes.”

Still, The Nature Conservancy — the one environmental group that has publicly commented on the Smackover developments — is cautiously supportive. The world needs to make a transition toward renewable power “with eyes wide open,” says Zollner. Developing a low-carbon economy “will take an incredible amount of infrastructure development, and we must minimize the environmental impact without halting the move into a low-carbon future.”