Uranium Is Widespread in U.S. Drinking Water, Study Finds

Photo: Justin Sullivan (Getty Images)

Some of the U.S. drinking water supply contains unsafe levels of uranium, new research out this month shows. The study analyzed data from the Environmental Protection Agency on drinking water systems across the country and found that uranium was frequently detected during compliance testing, and that a small percentage of systems are estimated to contain levels higher than the maximum allowed by the EPA. These sources of highly contaminated water were more likely to be near semi-urban, Hispanic communities.

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Uranium is a metallic and radioactive element. Though it’s often associated with nuclear power, the most common form of uranium is naturally found throughout our environment in small traces, including in soil, water, and air. Our bodies are routinely exposed to minute amounts of uranium as a result, but most of this uranium is thought to pass through our body quickly. High levels of acute uranium exposure can be fatal, however, and chronic low-level exposure has been linked to various health problems, such as a higher risk of kidney and heart damage.

Uranium poisoning tends to especially affect people who work in industries that use or collect uranium, such as certain kinds of mining. But the authors of this new research, published this month in the Lancet Planetary Health, say that little is known about the possible threats posed by uranium in our drinking water.


To better understand this risk, the researchers analyzed EPA compliance data from over 37,000 drinking water systems with available records across the U.S. They then used this data to estimate the average concentration of uranium and other metals in a drinking water supply, up through 2011. They’ve also now released an interactive map of their data for the public and other researchers to view.


The EPA sets a maximum contaminant level of uranium and other worrying metals that can be in our drinking water. Its stated goal, however, is for there to be no detectable uranium in drinking water at all. For most of the other metals included in their analysis, levels were minimal throughout the country. But the researchers found that around two-thirds of samples had levels of detectable uranium between 2000 and 2011. And during this time period, they estimated that 2.1% of systems had an average concentration higher than the EPA’s limit.

“Uranium is an underappreciated contaminant in U.S. public drinking water systems,” they wrote.


Previous research has suggested about 4% of private wells in the U.S. similarly contain higher-than-allowed levels of uranium. But according to the researchers, their findings are the first to show nationwide estimates of uranium contamination in public drinking water systems, which provide water to 90% of the country. The possible impacts of this contamination aren’t being felt equally, though.

Geographically, the highest concentrations of uranium tended to be found in the Southwest and Central Midwest regions of the U.S. High-uranium systems were most likely to be serving semi-urban and predominantly Hispanic communities. The study authors says this likely represents ongoing regulatory failures to protect marginalized communities and ensure safe drinking water for them. Indeed, research has found that high levels of other contaminants in our water, such as lead, are more likely to affect neighborhoods with higher rates of poverty.


It will take more research to untangle the relationship between higher levels of uranium in a drinking water supply and any potential health effects. But it may help explain the higher rates of chronic illness and overall worse health often seen in poorer neighborhoods. The study authors hope their work can motivate policymakers to enact the substantial reforms needed to keep our water free of uranium in the future, such as added regulations, better enforcement of systems that are violating EPA standards, and the speedier repair or improvement of infrastructure.

In a statement, study author Anna Nigra, assistant professor of environmental health sciences at the Columbia Mailman School of Public Health, said: “Such interventions and policies should specifically protect the most highly exposed communities to advance environmental justice and protect public health.”


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