About a third of U.S. residents have been receiving tap water containing a previously unidentified chemical byproduct, a new study has found. Some scientists are now concerned \u2014 and actively investigating \u2014 whether that chemical could be toxic. <\/p>\n\n\n\n
The newly identified substance, named \u201cchloronitramide anion,\u201d is produced when water is treated with chloramine, a chemical formed by mixing chlorine and ammonia. Chloramine is often used to kill viruses and bacteria in municipal water treatment systems. <\/p>\n\n\n\n
Researchers said the existence of the byproduct was discovered about 40 years ago, but it was only identified now because analysis techniques have improved, which finally enabled scientists to determine the chemical\u2019s structure. <\/p>\n\n\n\n
It could take years to figure out whether chloronitramide anion is dangerous \u2014 it\u2019s never been studied. The researchers reported their findings Thursday in the journal Science<\/a>, in part to spur research to address safety concerns. <\/p>\n\n\n\n The scientists said they have no hard evidence to suggest that the compound represents a danger, but that it bears similarities to other chemicals of concern. They think it deserves scrutiny because it\u2019s been detected so widely. <\/p>\n\n\n\n \u201cIt has similarity to other toxic molecules,\u201d said David Wahman, one of the study\u2019s authors and a research environmental engineer at the Environmental Protection Agency. \u201cWe looked for it in 40 samples in 10 U.S. chlorinated drinking water systems located in seven states. We did find it in all the samples.\u201d<\/p>\n\n\n\n Chloronitramide anion is produced as chloramine decays over time. It\u2019s likely to be found in all drinking water treated via this method, he said. <\/p>\n\n\n\n The fact that a byproduct with unknown risks could be so ubiquitous and evade researchers for so long renews questions about potential health effects of the chemicals used to treat tap water. <\/p>\n\n\n\n Some 113 million U.S. residents receive chloramine-treated water from their taps, according to the study. The chemical has been used for about a century to disinfect water. Today, it\u2019s often used to protect a system\u2019s \u201cresidual\u201d \u2014 the water that remains in pipes for several days after it leaves a water treatment plant. <\/p>\n\n\n\n Increasingly, chloramine has been favored over chlorine because the latter also produces byproducts, some of which are associated with bladder cancer and are regulated by the EPA. <\/p>\n\n\n\n David Reckhow, a research professor in civil and environmental engineering at the University of Massachusetts, Amherst, who was not involved with the study, said the finding was an important step. The ultimate goal, he said, is understanding whether the substance is a hazard; he concurred that it was likely toxic. <\/p>\n\n\n\n \u201cIt\u2019s a pretty small molecule and it can probably for that reason enter into biological systems and into cells. And it is still a reactive molecule,\u201d he said. \u201cThose are the kinds of things you worry about.\u201d <\/p>\n\n\n\n The authors of the new study arrived at their results after figuring out how to formulate high concentrations of the chemical for laboratory testing, said Julian Fairey, lead author and an associate professor at the University of Arkansas. <\/p>\n\n\n\n \u201cWe don\u2019t know the toxicity, but this study has enabled us to be able to do that work now,\u201d said Fairey, who studies drinking water byproducts. \u201cNow, we can go about the hard work of trying to figure out what its toxicological relevance is in our water systems.\u201d<\/p>\n\n\n\n He added that some past studies have suggested a link between drinking disinfected water and increased rates of certain cancers<\/a>.<\/p>\n\n\n\n \u201cWe don\u2019t know what\u2019s driving these. We have no idea if this compound is in any way related to those outcomes,\u201d Fairey said. \u201cBut we have unexplained incidents of certain types of cancer from treated drinking water.\u201d<\/p>\n\n\n\n However, any conclusions about whether the newly identified substance is toxic are likely many years away. Potential regulation based on those eventual findings would take even longer. <\/p>\n\n\n\n \u201cIt\u2019s a lot \u2014 probably a decade of research once a funding source is found,\u201d said Alan Roberson, executive director of the Association of State Drinking Water Administrators. <\/p>\n\n\n\n Reckhow said that in the meantime, water utilities should pay close attention to ongoing research and try to reduce people\u2019s exposure. <\/p>\n\n\n\n \u201cYou do what you can to minimize,\u201d he said. \u201cYou make the best judgment you can on the toxicity and you run with incomplete information. That\u2019s the world we live in, unfortunately.\u201d <\/p>\n\n\n\n The EPA only regulates a handful of disinfectant byproducts, including several associated with the use of chlorine. Scientists said those regulations have pushed some water providers to increase the use of chloramine.<\/p>\n\n\n\n \u201cThis study really calls into question whether or not this disinfection process is safer from a health perspective,\u201d said David Andrews, a senior scientist at the Environmental Working Group, an advocacy organization that pushes for more scrutiny of chemicals. <\/p>\n\n\n\n He added that there are hundreds of disinfection byproducts found in water systems but that this one deserves scrutiny. <\/p>\n\n\n\n \u201cMany of those other contaminants are occurring at lower concentrations or less frequently,\u201d Andrews said. <\/p>\n\n\n\n Any treatment of drinking water involves some level of health risk, Roberson said. It\u2019s a trade-off: Disinfection processes have largely vanquished waterborne diseases such as cholera and typhoid, but research suggests<\/a> that some byproducts are associated with risks of cancer and miscarriage.<\/p>\n\n\n\n \u201cThe reason you\u2019re adding the chloramine \u2014 you want to kill the bacteria and viruses, you have a real risk-risk trade-off,\u201d he said. <\/p>\n\n\n\n Many U.S. water utilities disclose on their websites whether they treat the water they supply with chlorine or chloramine. Wahman said some research suggests that active carbon filters, such as those used in home water purification devices or refrigerator filters, can remove disinfectant byproducts but that more research is needed.<\/p>\n\n\n\n