Lithium in drinking water is a widespread and persistent source of human exposure across Tribal communities in the Western United States, according to a July 24 study from Columbia University Mailman School of Public Health. The research documents significant regional variation and provides strong evidence that household drinking water is a major contributor to lithium levels measured in the body.
Researchers measured lithium concentrations in household tap water collected between 2022 and 2024 and compared these findings with urinary lithium levels from the same participants over a 15-year period. The study found that drinking water lithium frequently exceeded the U.S. Geological Survey's non-enforceable health-based screening level in Arizona and North Dakota/South Dakota, urinary lithium levels remained stable over time, and household drinking water explained a substantial proportion of the variation in urinary lithium concentrations.
"Our findings improve lithium exposure estimates among the Strong Heart Family Study communities and highlight the need for continued environmental monitoring and risk evaluation, particularly as lithium extraction and processing accelerate to meet growing energy demands," said Ellen Bannon, MPH, PhD student at Columbia Mailman School of Public Health.
Lithium demand is projected to increase more than six-fold by 2050 because it is an essential component of rechargeable batteries used in electric vehicles and renewable energy storage. At the same time, production and processing are expanding across regions on or near Tribal lands. While naturally occurring in groundwater, environmental releases from mining have raised questions about potential human exposure. In 2022, the U.S. Environmental Protection Agency added lithium to its Fifth Contaminant Candidate List for possible regulation under national drinking water standards.
The study analyzed tap water samples from 673 homes alongside urine samples from 613 Strong Heart Family Study participants living in Tribal communities across Arizona, Oklahoma, North Dakota, and South Dakota. Researchers found a median concentration of 35.6 micrograms per liter of lithium in household drinking water; every sample collected in Arizona exceeded federal health-based screening levels, as did most samples from North Dakota/South Dakota.
"By linking individually matched household drinking water measurements with biomonitoring data collected over more than a decade, our study establishes an important baseline for understanding environmental lithium exposure in U.S. communities," said Ana Navas-Acien, MD, PhD.
