For more than 40 years, scientists have known of the existence of a mysterious “phantom chemical” that lurks in US drinking water. And yet, they have been unable to determine its identity – until now.
A team of researchers from the US and Switzerland have discovered the chemical chloronitramide anion (CI-N-NO2). Chloronitramide anion is a by-product of inorganic chloramine, a group of chemicals that includes monochloramine (NH2Cl) and dichloramine (NHCl2) and are added to water systems to disinfect drinking water. The chemical has previously eluded chemists thanks to its stability and low chemical weight.
Professor Ian Rae, an expert on chemicals in the environment at the School of Chemistry at the University of Melbourne and an advisor to the United Nations Environment Programme on chemicals, described the research as a “wonderful bit of chemical detective work”.
“Who would have thought that such a simple combination would have remained undiscovered over several centuries of chemical research in which tens of thousands of chemicals have been put on the books, so to speak?” he said in a statement.
So, should we be concerned? Right now, it is too early to tell. However, researchers have warned that its pervasiveness in chloraminated drinking water and the similarities it shares with known toxic compounds is a worry and a cause for further investigation.
“It’s well recognized that when we disinfect drinking water, there is some toxicity that’s created. Chronic toxicity, really,” first co-author Julian Fairey, an associate professor of civil engineering at the University of Arkansas who has spent the last decade searching for it, said in a statement.
“A certain number of people may get cancer from drinking water over several decades. But we haven’t identified what chemicals are driving that toxicity. A major goal of our work is to identify these chemicals and the reaction pathways through which they form.”
To do so, Fairey and the team synthesized the newly discovered compound in a lab. It was then sent to Switzerland for further analysis. High-resolution mass spectrometry and nuclear magnetic resonance spectroscopy were used to identify chloronitramide anion.
Once identified, the researchers were able to compare concentrations of chloronitramide anion in 40 samples from ten US water systems. Some samples revealed concentrations up to 100 micrograms per liter, suggesting it may be present at levels above regulatory limits that require disinfection by-products to remain below 60 to 80 micrograms per liter.
Drinking water is regularly disinfected so as to remove harmful bacteria and other pathogens that lurk in H2O, such as those that cause cholera and typhoid fever.
“Chemical disinfection of drinking water is an extremely important practice, and one that has prevented millions of illnesses and premature deaths,” Stuart Khan, Professor and Head of School of Civil Engineering at the University of Sydney, said in a statement. Khan was not involved in the original study. “It is most certainly among the most impactful public health interventions of the last century.”
However, adding chemicals to water is not an entirely problem-free solution. While they do a very important job of eliminating disease-causing bugs, they do lead to by-products and while chloramine may produce fewer by-products than alternatives, it still causes by-products.
“It is well known that all chemical disinfectants, including chlorine and chloramines, lead to the production of disinfection byproducts,” said Khan. “It is also widely accepted that we don’t know the precise identity of all disinfection byproducts that are formed.”
Fairey says that even if this newly-discovered chemical proves to be non-toxic, the discovery could be useful in helping scientists understand how other, more toxic chemicals are formed and, consequently, help uncover ways to limit the health impact of these toxic chemicals on the general population.
This study is published in the journal Science.
Source Link: Researchers Identify “Phantom Compound” In US Drinking Water
