Study finds unsafe levels of uranium in American public water systems
Public water systems serving 290 million people in the United States per year were found to have high concentrations of uranium, a radioactive chemical that occurs naturally in soil, rock and water.
Researchers at the Columbia University Mailman School of Public Health found that 63.1 percent of community water systems (CWS) compliance monitoring records showed detectable concentrations of uranium, and that 2.1 percent of CWSs with available uranium data had 2000-11 average concentrations above the maximum contaminant levels.
“Despite relatively frequent detections and relatively high concentrations compared with other metals in our study, uranium has been underappreciated in the literature as a public drinking water contaminant of concern,” the researchers said.
The study, which aimed to estimate metal concentrations among CWS across the country, identified sociodemographic subgroups serviced by CWS that reported high levels of metal concentration and characterized metal mixture profiles in CWSs nationwide.
For the study, the researchers looked at six-year review records of metals such as uranium, arsenic, antimony, beryllium, barium, thallium, mercury, selenium, chromium and cadmium that have been compiled by the Environmental Protection Agency (EPA).
The review also checked whether the average concentrations of these metals exceeded the standards set by the EPA, with the research team going through 13 million records from 139,000 public water systems that serve 290 million people per year.
The study pointed out that uranium is an important risk factor for the development of chronic diseases, even at low concentrations. Previous studies have already associated exposure to uranium with medical conditions, such as lung cancer, kidney damage, hypertension and cardiovascular diseases.
Uranium itself becomes part of water by leaching from rocks and soil. It is also released by processing plants, which push the element into the water. Prolonged exposure to uranium can lead to toxic effects, such as the inflammation of the kidneys and changes in the composition of urine.
Moreover, it is also capable of decaying into other radioactive substances like radon, which causes cancer among those who have been exposed to it for too long. When contaminated, drinking water can also result in the deformity of bones and the liver.
Geographic water systems in the southwest and central midwest regions
Geographically, the highest concentrations of uranium were found in the Southwest and Central Midwest regions, with high-uranium systems likely to be serving semi-urban and predominantly Hispanic communities. The researchers say this likely represents ongoing regulatory failures to protect the marginalized communities and ensure safe drinking water for them.
Research also found that there are high levels of other contaminants such as lead, which is more likely to affect neighborhoods with higher poverty rates.
The consistent association between high metal concentrations in CWS services among semi-urban, Hispanic communities is also an indication that disparities in concentrations are due to the failure of regulatory policies than geology. Hispanic and Latino populations tend to show increased mortality due to cardiovascular, kidney, liver disease and diabetes.
Anne Nigra, one of the authors of the study, said additional regulatory policies, compliance enforcement and improved infrastructure are necessary to reduce such disparities in CWS metal concentrations served by public water systems with elevated metal concentrations.
Uranium poisoning also tends to affect those who work in industries that use or collect uranium, such as certain kinds of mining. However, little is known about the possible threats posed by uranium in drinking water.
Previous research suggested that about four percent of private wells in the U.S. similarly contain higher-than-allowed levels of uranium, but nationwide estimates of uranium contamination in public drinking water systems, which provide water to 90 percent of the country were found first by the Columbia research.
“Such interventions and policies should specifically protect the most highly exposed communities to advance environmental justice and protect public health,” said Nigra.
September 18, 2022