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.

Subject of Research: Lithium exposure in Tribal communities via household drinking water and urinary biomonitoring
Article Title: Lithium exposure in areas of the Western United States: Water and urinary levels in the Strong Heart Family Study
News Publication Date: July 24, 2026
Web References: https://www.nature.com/articles/s41370-026-00947-7
References: 10.1038/s41370-026-00947-7
Image Credits: Not provided in the provided content

Keywords: lithium exposure, drinking water, biomonitoring, urine lithium, Tribal communities, environmental health, Strong Heart Family Study, exposure science, water screening levels, lithium extraction