Posted on Feb 03, 2020, 1 p.m.
One of the most common methods of disinfecting drinking water is to add chlorine to it. New evidence published in the journal Environmental Science & Technology has been found by Johns Hopkins researchers that this practice is not as safe as was once thought because the reactions between chlorine and natural compounds in water may produce previously unknown toxic byproducts.
Chlorine is a powerful disinfectant able to kill viruses, bacteria and other microbes, as such it has been credited with halting waterborne diseases such as typhoid and cholera when it began to be used to treat drinking water early 20th century.
Chlorine reacts with phenols naturally found in water that have been found to create potentially harmful byproducts. According to a report from W.H.O “the risks to health from these byproducts are extremely small in comparison with the risks associated with inadequate disinfection.”
Recently researchers have found signs of new byproducts that have been undetected until now, suspecting that current methods of analyzing the chemistry of drinking water may be missing some byproducts another technique was used. N-a-acetyl-lysine amino acids often used in toxicology to detect harmful reactive electrophile molecules were added to water that had already been traditionally treated and left to sit for a full day before running their analysis using mass spectrometry.
Analysis revealed 2 related compounds in the water that are known to be toxic and carcinogenic that have never been detected in drinking water before: 2-butene-1,4-dial (BDA), and chloro-2-butene-1,4-dial (BDA with chlorine). It was noted that these chemicals were found under lab conditions, and there still is question over whether these compounds are at high enough concentrations to pose a threat to human health, and over whether the tradeoff for preventing waterborne illness may be for the greater good.
"There's no doubt that chlorine is beneficial; chlorination has saved millions of lives worldwide from diseases such as typhoid and cholera since its arrival in the early 20th century," says Carsten Prasse, lead author of the study. "But that process of killing potentially fatal bacteria and viruses comes with unintended consequences. The discovery of these previously unknown, highly toxic byproducts, raises the question how much chlorination is really necessary."
“Our study also clearly emphasizes the need for the development of new analytical techniques that allow us to evaluate the formation of toxic disinfection by-products when chlorine or other disinfectants are being used,” says Prasse. “One reason regulators and utilities are not monitoring these compounds is that they don't have the tools to find them.”
There are other methods to disinfecting drinking water beside using chlorine readily available such as ozone, UV light or filtration to keep water borne diseases at bay that are currently being utilized in other countries around the world efficiently without producing any toxic byproducts. The researchers suggest that it may be time to put these approaches into effect in even wider use.
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