What to know about the newly identified chemical found in certain US drinking water

Scientists have identified a chemical in certain tap water across the United States, raising questions about what it means for drinking water safety and the health of Americans.

In the study, published in journal Science On Thursday, researchers detected the compound, called chloronitramide anion, in 40 drinking water samples from 10 US drinking water systems using chloramines, a type of disinfectant.

The levels of the newly identified chemical were also notable, as high as about 100 micrograms per liters (μg/l), which exceeds the typical regulatory limits of 60 to 80 μg/l for many disinfection by-products.

The compound was not detected in ultrapure water or drinking water treated without chlorine-based disinfectants.

While the existence of the chloronitramide anion has been known for about 30 years, this new research identifies it, sheds light on how widespread it is in American drinking water, and paves the way for further testing.

Where does the chloronitramide anion come from?

Chlornitramide anion is a by-product of chloramine degradation. Chloramines are used to disinfect drinking water.

“For more than a century, chemical disinfection of public water supplies has effectively reduced waterborne diseases by killing pathogens in drinking water,” a news release to the study notes. “Inorganic chloramines, such as monochloramine (NH22Cl) and dichloramine (NHCl2), have been widely used in the United States for this purpose and are used to treat the tap water of nearly one-third of Americans.”

More precisely, chloraminated water systems serve more than 113 million people in the United States alone, the study notes. For decades, however, chloramine degradation has been suspected of producing elusive chemical byproducts.

pHowever, some still consider chloramine a better option than chlorine, the most common drinking water disinfectant used, due to known health concerns.

“Since the 1970s, we’ve known that chlorine reacts with constituents in the water to form disinfection byproducts that have been linked to bladder and colon cancer, low birth weight, weight and miscarriage,” said author Julian Fairey in a press briefing. addition of the most prevalent chlorine disinfection by-products is regulated by the Danish Environmental Protection Agency.

This prompted many public water systems to switch from chlorine to chloramines, Fairey said, because they form lower concentrations of these regulated disinfection byproducts.

But chloramines still break down into products that are not well studied, like the most recently identified compound.

Is chlornitramide anion toxic?

The study emphasizes that any potential toxicity is not currently known, but adds the prevalence of the compound and its similarity to other toxic molecules is concerning.

“The toxicity of this compound, detected in millions of Americans’ tap water, remains untested, prompting calls for immediate toxicological evaluation and raising questions about the safety of chloramine in public water supplies,” the release added.

In a related comment shared with the study, civil and environmental engineering professor Daniel McCurry writes that the findings could trigger a reassessment of how water supplies are treated.

“Whether or not the chloronitramide anion turns out to be toxic, its discovery warrants a moment of reflection for water scientists and engineers,” he writes.

In the news briefing, the study’s authors reiterated that further testing is needed to understand any potential health consequences of chlornitramide anion in drinking water.

Still, if people are currently concerned about their drinking water while any potential toxicity has yet to be evaluated, study author David Wahman said in the briefing that previous literature has shown that the byproduct is removed with activated charcoal.

“A Brita filter or something like that is probably logical … Any kind of carbon-based filter that you have in your fridge would probably remove it. If someone was concerned, that would be the one thing that maybe they could think about doing,” he said.