Long-Term Research Reveals Widespread Lithium Contamination in Western Drinking Water

Lithium is a quiet but persistent ingredient of everyday exposure for many Tribal communities across the Western United States, according to a new study from Columbia University Mailman School of Public Health. Researchers combined measurements from household tap water with urine biomonitoring collected over more than a decade, offering one of the clearest pictures yet of how environmental lithium translates into human uptake.

The team measured lithium concentrations in water samples collected from 673 homes between 2022 and 2024. To connect those environmental readings to internal exposure, they analyzed urinary lithium from 613 participants in the Strong Heart Family Study, with urine data spanning a 15-year period.

A striking finding was regional variability. In Arizona, every household water sample exceeded a U.S. Geological Survey screening level of 10 micrograms per liter. In the Dakotas and South Dakota, 93% of samples surpassed the same threshold, while in Oklahoma 35% did. Overall, nearly three-quarters of the household samples were above the screening level.

Despite this variation in water chemistry, urinary lithium levels were remarkably consistent over time. Median urinary concentrations from 2006–2009 were nearly identical to those from 2022–2024, suggesting long-term, stable exposure patterns rather than short-lived spikes.

The study also quantified how strongly drinking water shapes what appears in the body. Lithium in household tap water correlated with urinary lithium at both study visits, and household drinking water accounted for about 29% of the variation in urine concentrations—evidence that water is a major driver of exposure.

The authors highlight urinary lithium as a reliable biomarker for environmental uptake. Geography remained a strong predictor even when bottled water use was considered, implying that underlying regional factors—such as geology and water sources—continue to govern exposure.

Lithium demand is projected to grow more than six-fold by 2050 as rechargeable batteries expand across electric vehicles and renewable energy storage. Meanwhile, lithium extraction and processing are accelerating within the United States, including in or near areas affecting Tribal lands, raising concerns about future exposure pathways.

Because lithium is not currently regulated under the Safe Drinking Water Act and can be difficult to remove once present, the health implications of chronic, low-level exposure remain uncertain. The study’s core contribution is establishing a baseline linking individual water measurements to long-term biomonitoring.

Ultimately, the researchers argue for continued environmental monitoring and risk evaluation. By linking water chemistry to biomonitoring across time, the work provides a practical framework for tracking lithium exposure as industrial activity and battery production scale up.