Approximately one-third of Americans may be exposed to the long-sought, newly identified degradation products of some chlorine-based water treatments.
The toxicity of the by-product, charged molecules, is not yet known, but analysis suggests that this substance may have several harmful effects on health. That’s a concern for some water systems. Chemicals appear at concentrations above thresholds Allowed for other harmful decomposition products, researchers reported Nov. 21 science.
“This paper is going to cause quite a stir,” said Daniel McCurry, an environmental engineer at the University of Southern California, Los Angeles. Although he was not involved in this research, he wrote the following paper: Perspective on research about the same problem science.
Most water systems in the United States disinfect their water with chlorine. Although dissolved gases effectively kill bacteria, they react with other substances in the water and produce hundreds of byproducts, some of which are harmful. As a result, some municipalities switched decades ago to treating water with chemicals called chloramines, said Julian Fairley, an environmental engineer at the University of Arkansas, Fayetteville.
Nationwide, approximately 113 million people receive their drinking water from systems that use chloramines as disinfectants. These nitrogen and chlorine compounds also produce decomposition products, but at generally much lower rates than chlorine. Although many of the chloramine byproducts found in drinking water are readily identified, one has remained unexplained for decades.
Previous experiments have suggested the existence of another byproduct, one that contains nitrogen and absorbs certain wavelengths of light, but researchers have not been able to identify it separately from other byproducts. I couldn’t. Using a combination of analytical techniques, Fairey and his colleagues eventually identified the mysterious substance, a negatively charged molecule called chloronitramid. Its small size, with only five atoms, allowed it to exist hidden among other decomposition products, among other factors, Fairey said.
According to the research team’s field studies, chloronitramid was not detected in Swiss water treatment systems that do not use chlorine or chloramine disinfectants. However, in the 10 US systems that use chloramines to treat water, 40 samples contained an average of 23 micrograms per liter, with the highest concentration reaching a whopping 120 μg/l. For comparison, the U.S. Environmental Protection Agency regulates concentrations of some degradation products known to be harmful at 80 μg/l or less.
The researchers note that the potential health effects of chlornitramine have not yet been studied in detail. Therefore, this substance is not regulated. However, using a web app to conduct a preliminary evaluation of newly identified substances suggests that there may be dozens of concerns, including toxicity and adverse effects that occur during prenatal development.
Beate Escher, a toxicologist at the Helmholtz Center for Environmental Research in Leipzig, Germany, said: “So many chemicals are produced in the chlorination and fluorination processes that it is difficult to determine which ones are causing disease. ” he says. New study. She points out that detailed laboratory studies are needed to determine whether chlornitramide is harmful.
While the health risks may be worth worrying about for the population as a whole, they probably aren’t worth worrying about on an individual basis because of the large number of people involved, McCurry said. “I drink tap water at home and everywhere I go,” he says. The potential risks from chlornitramide are “not enough to stop drinking tap water,” he says.
