The tap water for about 1 in 3 Americans may contain a byproduct of the decontamination process that could be toxic, according to a study released Thursday.
For more than a century, public water systems have used chemical compounds to kill pathogens that cause waterborne diseases such as cholera and typhoid fever., save countless lives. This purification process was carried out using chlorine. In the 1970s, researchers discovered that chlorine could react with organic compounds in water to produce chemical reactions that cause cancer, low birth weight and miscarriage.
Since the 1990s, many public systems have switched to inorganic chloramine, a chlorine derivative, to purify water supplies. Systems serving approximately 113 million people in the United States use this process. This alternative purification chemical produces hundreds of byproducts, including an “unidentified product” that has baffled scientists.
In the results published in the journal Science, the researchers identified this compound, the chloronitramide anion. They found that it carries possible risks related to carcinogens and could be harmful to reproductive and developmental health.
“There are, I would say, good reasons to investigate toxicity,” lead author Julian Fairey, an associate professor of engineering at the University of Arkansas, told reporters during a briefing. press. “And these studies must begin.”
The study raises questions about methods used for decades to disinfect water and could prompt a search for safer techniques to rid water supplies of pathogens.
In a statement, the U.S. Environmental Protection Agency said the study advanced understanding of the chloramine byproduct, but said regulatory action would only be taken after further investigation .
The federal agency develops regulations using the processes outlined in the Safe Drinking Water Act. These processes rely on the best available peer-reviewed science, the EPA statement said.
This byproduct may not have dramatic effects, especially since research has not yet shown population-level harm, said David Sedlak, director of the Berkeley Water Center, who did not participate in the study.
Water treatment has been hugely successful in most communities, said Sedlak, also a professor at the University of California, Berkeley. The challenge is to detect and address problems when they arise, including during disinfection.
“It’s best to solve this problem at the drinking water treatment plant level,” he told USA TODAY. “This way, everyone in our community is protected. »
With a grant from the National Science Foundation, Fairey and scientists from the EPA and ETH Zurich, a Swiss public university, isolated and identified the byproduct of the breakdown of inorganic chloramines.
The researchers then applied their technique to 10 drinking water systems using chloramine in seven US states. All 40 samples collected contained the byproduct.
Byproduct levels reached 120 micrograms per liter of water, the study found, above regulatory limits for many disinfection byproducts, which tend to be around 60 to 80 micrograms per liter. The median concentration found in the study was 23 micrograms per liter. The anion byproduct chloronitramide was not found in water systems using alternative disinfectants, the researchers noted.
Using EPA analyses, researchers sought to assess potential risks associated with the compound. They found that the chloronitramide anion was linked to 84 categories of harm to humans, including chronic toxicity, prenatal development, and toxicity that can be passed down through generations.
The study concluded that the byproduct “poses a potential problem for human health” and called for immediate assessment of its levels in water sources, drinking water and wastewater. The researchers also suggested “further evaluation of its carcinogenicity and reproductive and developmental toxicities.”
David Andrews, deputy director of investigations and senior scientist at the nonprofit Environmental Working Group, said the study shows there is a need for better national monitoring and toxicity data to assess overall risk. The group has its own list of harmful compounds.
“These disinfectant byproducts have health implications and hazards,” he said. “This highlights the need for a comprehensive assessment of our drinking water quality and water filtration.”
The toxic effects of this byproduct are not yet known, said David Wahman, an environmental research engineer at the EPA who co-authored the study. Researchers recommend that people use a Brita filter or similar product for tap water. These filters use carbon to rid tap water of these compounds.
This article originally appeared on USA TODAY: Byproducts of tap water purification could be toxic, study finds
