July 21, 2025--A new study by researchers at Columbia University Mailman School of Public Health identified that uranium's isotopic composition can be used as a biomarker to noninvasively measure accumulation of uranium in the kidneys. Uranium from drinking water can accumulate in the kidneys—even at low levels of exposure—and this newly identified biomarker may serve as an early warning sign of kidney damage. The findings, published in Environmental Science & Technology, suggest a potential breakthrough in detecting and preventing chronic kidney disease caused by uranium toxicity. This discovery offers critical insights into a largely overlooked environmental health threat.
"Uranium that enters the body through drinking water is filtered by the kidneys, where some of it is retained and can cause harm over time," said senior author Anirban Basu, PhD, a geochemist and research scientist at Columbia Mailman School. "Our study suggests that uranium isotopes in urine may provide a sensitive, noninvasive biomarker for detecting kidney accumulation and the risk of damage."
Widespread Exposure
According to federal data, nearly two-thirds of U.S. community water systems—serving approximately 320 million people—have detectable uranium levels. About 2% of these systems exceed the EPA's maximum contaminant level (MCL) of 30 micrograms per liter (μg/L). Among private wells, which supply water to roughly 15% of the population, about 4% exceed the MCL.
While uranium is best known as a radioactive element, its chemical toxicity—particularly to the kidneys—is the more pressing concern at environmental exposure levels. Studies show that even low concentrations of uranium (below the 30 μg/L MCL) may impair kidney function.
"Our findings raise particular concern for communities in the Great Plains and the Colorado Plateau, including many Native American populations, where natural uranium deposits and legacy mining activity have led to high groundwater contamination," added Basu.
Health Impacts and the Need for Better Detection
Roughly 80% of ingested uranium is excreted in urine within days, but the remainder can accumulate in the kidneys—especially in the outer layer, where it binds to cells, causes injury, and interferes with vital functions. Over time, this damage can contribute to chronic kidney disease.
"Current tools to measure uranium in the body don't tell us how much is accumulating in the kidneys specifically – this is a big roadblock to understanding and preventing long-term kidney damage from uranium exposure," said first author Catherine Lucey, a doctoral student in environmental health sciences at Columbia Mailman School.
In experiments with mice, researchers found uranium accumulation in both the kidneys and bones with distinct isotopic signatures after just 7 to 14 days of exposure to contaminated water. This is the first in vivo evidence that molecular uranium uptake alters the proportions of its isotopes detectable in organs and in urine.
Because uranium's isotopic signature is detectable in urine, this biomarker could enable cost-effective and noninvasive monitoring of kidney uranium levels—especially useful in communities at higher risk of exposure.
"Our results support the development of new models to predict how uranium travels through the body—from ingestion to accumulation and excretion," said Lucey. "This work lays the foundation for precision biomarkers that could lead to earlier intervention—before irreversible kidney damage occurs."
The study is part of a broader effort to improve environmental health surveillance and develop tools for monitoring metal exposures in vulnerable populations. The researchers plan future studies with longer exposure periods and lower uranium doses to better understand long-term effects.
Other co-authors include Brandon L. Pearson, Kathryn DeSantis, Ana Navas-Acien, Kathrin Schilling, and Jeff Goldsmith of Columbia Mailman School of Public Health, and Alex N. Halliday of the Lamont-Doherty Earth Observatory at Columbia Climate School.
The study was supported by the Columbia University Northern Plains Superfund Research Program (Grant P42ES033719); the National Institute of Environmental Health Sciences (Grants P30ES009089 and T32 ES007322); and the National Center for Advancing Translational Sciences, NIH (Grant TL1TR001875).
Columbia University Mailman School of Public Health
