Tap water for about 1 in 3 Americans could contain a byproduct from the decontamination process that may be toxic, according to a study published Thursday.
For over a century, public water systems have used chemical compounds to kill pathogens that cause waterborne diseases such as cholera and typhoid fever, saving countless lives. This purification process has been carried out using chlorine. In the 1970s, researchers found chlorine could react to organic compounds in water to produce chemical reactions that cause cancer, low birth weight babies and miscarriages.
Since the 1990s, many public systems have switched to inorganic chloramine, a chlorine derivative, to purify water supplies. Systems serving about 113 million people in the U.S. use this process. This alternative purifying chemical produces hundreds of byproducts, including an “unidentified product” that befuddled scientists.
In findings published in the journal Science, researchers have identified that compound, chloronitramide anion. They found it has possible risks linked to carcinogens and could be harmful to reproductive and developmental health.
“There is, I would say, good reason to investigate the toxicity,” lead author Julian Fairey, an associate professor of engineering at the University of Arkansas, told reporters in a briefing. “And those studies need to commence.”
The study raises questions about methods used for decades to disinfect water and could prompt research into safer techniques for ridding water supplies of pathogens.
In a statement, the U.S. Environmental Protection Agency said the study advanced the understanding of the byproduct from chloramine, but said regulatory action would only happen after further investigation.
The federal agency develops regulations using processes outlined in the Safe Drinking Water Act. These processes rely on the best available peer-reviewed science, the EPA statement said.
There may not be dramatic effects from this byproduct, especially since research hasn’t yet shown harms at the population level, said David Sedlak, director of the Berkeley Water Center, who was not involved in the study.
Water treatment has been immensely successful in most communities, said Sedlak, who is also a professor at the University of California, Berkeley. The challenge is to detect and treat issues when they arise, including during disinfection.
“It’s best to solve this problem at the drinking water treatment plant,” he told USA TODAY. “That way everyone in our community is protected.”
With backing from a National Science Foundation grant, Fairey and scientists from EPA and ETH Zurich, a public university in Switzerland, isolated and identified the byproduct from inorganic chloramine decomposition.
Researchers then applied their technique in 10 drinking water systems that use chloramine in seven U.S. states. All 40 samples collected had the byproduct.
Levels of the byproduct were as high as 120 micrograms per liter of water, the study found, above the 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 chloronitramide anion byproduct was not found in water systems that used alternative disinfectants, researchers noted.
Using EPA analyses, researchers sought to assess potential risks from the compound. They found chloronitramide anion was linked to 84 categories of harm to humans, including chronic toxicity, prenatal development and toxicity that can pass from generation to generation.
The study concluded the byproduct “is a potential human health concern” and called for an immediate evaluation of its levels in water sources, finished drinking water and wastewater. Researchers also suggested further “assessment 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’s 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 do have health implications and health harms,” he said. “It points to the need for, really, a comprehensive evaluation of our drinking water quality and water filtration.”
The toxic effects of this byproduct aren’t yet known, said David Wahman, a research environmental engineer at the EPA, who was a co-author of the study. Researchers recommend people use a Brita filter or similar product for tap water. These filters use carbon to rid tap water of such compounds.
This article originally appeared on USA TODAY: Byproduct of tap water purification could be toxic, study says
