‘Unidentified product’ found in US tap water may be toxic, study says

The tap water of about one in three Americans may contain a byproduct of the disinfection process that can be toxic, according to a study released Thursday.

For more than a century, public water supplies have used chemicals to kill pathogens that cause waterborne diseases such as cholera and typhoid., saving countless lives. This cleaning process was carried out using chlorine. In the 1970s, researchers discovered that chlorine can react with organic compounds in water, causing chemical reactions that cause cancer, low birth weight babies and miscarriages.

Since the 1990s, many public systems have switched to inorganic chloramine, a derivative of chlorine, to treat water. Systems serving approximately 113 million people in the United States use this process. This alternative cleansing chemical produces hundreds of byproducts, including an “unidentified product” that has baffled scientists.

In results published in the journal Science, the researchers identified the compound as the chlornitramide anion. They found that it has possible risks associated with carcinogens and may harm reproductive and developmental health.

“I would say there is a compelling reason to study toxicity,” study lead author Julian Fairey, an assistant professor of engineering at the University of Arkansas, told reporters at a briefing. “And these studies need to begin.”

The study raises questions about methods that have been used for decades to disinfect water and may prompt research into safer methods of ridding water of pathogens.

In a statement, the U.S. Environmental Protection Agency said the study advanced the understanding of the chloramine byproduct, but noted that regulatory action would only be taken after further investigation.

The federal agency develops regulations using processes outlined in the Safe Drinking Water Act. These processes are based on the best available scientific research, the EPA said in a statement.

This byproduct may not have serious consequences, especially since studies have not yet shown harm at the population level, says David Sedlak, director of the Berkeley Aquatic Center, who was not involved in the study.

Water treatment has been extremely successful in most communities, says Sedlak, who is also a professor at the University of California, Berkeley. The goal is to identify and correct problems as they arise, including during disinfection.

“The best way to address this problem is at a drinking water treatment plant,” he told USA TODAY. “This way, everyone in our community is protected.”

With support from a grant from the National Science Foundation, Fairey and scientists from the EPA and ETH Zurich, a public university in Switzerland, isolated and identified a byproduct of the decomposition of inorganic chloramine.

The researchers then applied their technique to 10 drinking water systems that use chloramine in seven US states. All 40 samples collected contained the byproduct.

The study found byproduct levels reached 120 micrograms per liter of water, which exceeded regulatory limits for many disinfection byproducts, which are typically between 60 and 80 micrograms per liter. The average concentration found in the study was 23 micrograms per liter. The researchers noted that the anion byproduct chloritramide was not detected in water supplies that used alternative disinfectants.

Using the EPA’s analysis, the researchers sought to assess the potential risks associated with this compound. They found that the chloritramide anion is associated with 84 categories of harm to humans, including chronic toxicity, intrauterine toxicity, and toxicity that can be transmitted intergenerationally.

The study concluded that the byproduct “poses a potential threat to human health” and called for immediate assessment of its levels in water sources, finished drinking water and wastewater. The researchers also suggested further “evaluation of its carcinogenicity and reproductive and developmental toxicity.”

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 do have health effects and harm,” he said. “This points to the need for a truly comprehensive assessment of the quality of our drinking water and its filtration.”

The toxic effects of this byproduct are not yet known, said David Wachman, an environmental research engineer at the Environmental Protection Agency who co-authored the study. The researchers recommend that people use a Brita filter or a similar product for tap water. These filters use carbon to remove such compounds from tap water.

This article originally appeared on USA TODAY: Tap water treatment byproduct may be toxic, study says