A team of international researchers has identified a previously undetected chemical compound in U.S. drinking water, sparking questions about its potential impact on public health. The compound, named chloronitramide anion, was discovered in water treated with inorganic chloramines — a disinfectant used by water utilities since the 1930s. Currently, over 113 million Americans, or roughly one in five, consume water treated with chloramines.
“Protecting America’s drinking water is a top priority for the EPA,” the Environmental Protection Agency (EPA) said in an emailed statement.
What is Chloronitramide anion?
The newly identified compound forms as a byproduct of chloramine disinfectants, which are widely used due to their ability to kill germs in water pipes more effectively over time compared to chlorine. Chloramine-treated water is considered safe at levels up to four milligrams per liter, according to regulatory guidelines. However, the discovery of chloronitramide anion raises fresh concerns.
“It’s a very stable chemical with a low molecular weight,” said Julian Fairey, an associate professor of civil engineering at the University of Arkansas and co-author of the study published in Science.
“It’s a very difficult chemical to find. The hardest part was identifying it and proving it was the structure we were saying it was.” Fairey’s team successfully synthesized chloronitramide anion in the lab for the first time, providing definitive evidence of its existence and formation pathways.
A decades-long mystery
Although researchers have suspected the presence of chloronitramide anion for decades, its exact structure remained elusive until now. The compound forms as inorganic chloramines decay during water treatment. Scientists are now investigating whether it poses a risk to human health.
“It’s prevalence and similarity to other toxic compounds is concerning,” Fairey noted. However, its toxicity remains unconfirmed. Experts say its discovery could pave the way for understanding how harmful byproducts are created during water disinfection processes. “Even if it is not toxic, finding it can help us understand the pathways for how other compounds are formed, including toxins,” Fairey added. “If we know how something is formed, we can potentially control it.”
The broader implications for water safety
The EPA emphasized its commitment to ensuring all Americans have access to safe drinking water, noting that it relies on peer-reviewed science to evaluate potential contaminants under the Safe Drinking Water Act. The agency has yet to determine whether chloronitramide anion will be regulated, pending further research into its health effects and occurrence in water systems.
While scientists have long known that disinfecting water can produce some toxic byproducts, identifying the specific chemicals driving these effects has been challenging. Chloramine-treated water has previously been linked to cancer-causing carcinogens, although studies have not established a strong connection between fluoride levels in drinking water and cancer, according to the American Cancer Society.
Looking ahead
The discovery of chloronitramide anion highlights the complexities of balancing effective water disinfection with minimizing potential health risks. As researchers delve deeper into its impact, the findings could have significant implications for water treatment practices and public health safeguards.
