Makenzie Huber/South Dakota Searchlight
Much of South Dakota’s drinking water has more naturally occurring lithium in it than the federal government preliminarily advises as a healthy level, according to numbers in a recent study released by the U.S. Geological Survey.
Lead study author Melissa Lombard hopes the data contributes to further research.
“Lithium is becoming recognized as potentially having impacts to human health,” Lombard told South Dakota Searchlight. “But first we need to identify the amount people are being exposed to through drinking water and study how different concentration levels may impact them. This is a first step in the process, and this will inform public health studies.”
The Environmental Protection Agency does not currently regulate lithium but is gathering information for potential future regulations. Meanwhile, the agency has established a “health reference level” indicating that concentrations above 10 micrograms per liter may be unhealthy. The agency stresses that health reference levels “are not final determinations” and that the science on lithium’s health effects is “still evolving.”
The USGS study used data collected between 1989 and 2020 from more than 18,000 drinking water supply wells in the United States. South Dakota was among 10 Western or Great Plains states with widespread concentrations greater than 30 micrograms per liter — three times the EPA’s health reference level.
More recent data shows about 85% of South Dakota drinking water samples taken in 2023 for the U.S. Environmental Protection Agency had lithium concentrations above the health reference level.
Lithium is used in medications to treat bipolar disorder and depression, and low levels of naturally occurring lithium in drinking water have been linked to positive health effects, such as reduced suicide mortality and other mental-health benefits, the USGS said. But lithium has also been linked to potentially negative outcomes with autism and thyroid hormone levels.
Among data collected for the EPA by the South Dakota Association of Rural Water Systems, the drinking water tested in Wall had the highest level of lithium in the state, at 238 micrograms per liter.
West River/Lyman-Jones Rural Water System operates four wells in the Wall, Quinn and Creighton areas that provide about 15% of the system’s supply. The system also draws water from the Missouri River via the Mni Wiconi pipeline.
West River/Lyman-Jones Manager Jake Fitzgerald said in an emailed statement that the system is complying with EPA testing requirements and plans to share results in its annual water quality report. He said customers should contact their physician if they are concerned about health implications from testing results.
He said his house is connected to the system, “and my family and I drink water directly from the tap on a daily basis and will continue to do so.”
Fitzgerald added that if the EPA establishes a national primary drinking water standard for lithium, the water system will “evaluate our options” to address it and ensure drinking water meets the standard.
Levels of 100 micrograms per liter or more were also reported in the city of Huron, in the Britton-based Brown-Day-Marshall Rural Water System, in the Beresford-based South Lincoln Rural Water System, and in the city of Aberdeen.
A drinking water system in Utah has the highest reported lithium levels in the country, according to EPA data, at 960 micrograms per liter.