A New Toxic Chemical Is Lurking in America’s Drinking Water

Toxic pollutants continue to be detected in America’s drinking water, putting millions of Americans at risk for chronic disease. According to a report from the National Resources Defense Council (NRDC):¹

“Chronic underinvestment has left water infrastructure outdated and on the verge of collapse in many places across the country …

Lead, per- and polyfluoroalkyl substances known as PFAS, industrial pollution, and agricultural runoff are contaminating the drinking water for hundreds of millions of people — and many don’t even know it.”

PFAS, also known as forever chemicals, have been linked to different diseases, such as cancer, liver problems, abnormal fetal development and hormone disruption.² Now, the list of pollutants has gotten longer. Researchers have discovered a pollutant so new that its effects on public health haven’t been determined yet — chloronitramide anion.

Chloronitramide Anion — A New Byproduct Identified in US Drinking Water

A study published in Science investigated the presence of a previously unidentified byproduct resulting from the decomposition of inorganic chloramines in U.S. drinking water systems. The research focused on chloraminated water, which is a common disinfectant treatment aimed at preventing the growth of harmful microorganisms.³ For context, chloramine is a mixture of chlorine and ammonia.⁴

The study examined 10 chloraminated drinking water systems across the United States, serving more than 113 million people. By analyzing 40 water samples from these chloraminated systems, the researchers discovered “chloronitramide anion” (Cl–N–NO2−), a new byproduct formed during the breakdown of mono- and dichloramines.⁵ It was consistently detected in all tested samples.⁶

The water samples had median concentration of 23 micrograms per liter, with the actual range going as low as 1.3 micrograms per liter to as high as 92 micrograms per liter. Notably, chloronitramide anion was absent in ultrapure water and in drinking water systems that do not use chlorine-based disinfectants, indicating a direct link between chloramine usage and its formation.⁷

While the exact toxicity of chloronitramide anion remains unknown, its structural similarity to other toxic molecules suggests that its prevalence poses significant health implications.⁸ According to a report from NBC News:⁹

“It could take years to figure out whether chloronitramide anion is dangerous — it’s never been studied …

The scientists said they have no hard evidence to suggest that the compound represents a danger, but that it bears similarities to other chemicals of concern. They think it deserves scrutiny because it’s been detected so widely.”

Now that scientists know what the byproduct is, they’re now moving onto the study phase. According to lead author Julian Fairey, “Now, we can go about the hard work of trying to figure out what its toxicological relevance is in our water systems.”¹⁰

Chlorinated Water Linked to Higher Colorectal Cancer Risk in Men

In another study, conducted in Sweden, researchers delved into how long-term exposure to trihalomethanes (THMs) in chlorinated drinking water influence the chances of developing colorectal cancer. Researchers aimed to uncover whether elevated levels of these byproducts, commonly found in treated water, could be a significant risk factor for this type of cancer:¹¹

“Although several drinking-water disinfection byproducts are confirmed rodent carcinogens, the evidence in humans for carcinogenicity associated with these byproducts, including colorectal cancer, is still inconclusive.”

The study examined 58,672 participants (32,872 men and 25,800 women), drawing data from the Swedish Mammography Cohort and the Cohort of Swedish Men. Participants were monitored over an average period of nearly 17 years, accumulating over 988,000 person-years of data. The focus was on individuals who consumed water from public systems, ensuring that the findings were relevant to typical drinking water sources.¹²

Findings revealed a connection between high THM concentrations (15 micrograms per liter or more) and an increased risk of proximal colon cancer in men. Specifically, exposure at this range puts men at a 59% greater risk compared to those with lower exposure. Interestingly, the study did not observe a similar association in women, indicating that the risk differs based on gender.¹³

The research also highlighted that the proximal part of the colon, the section closest to the small intestine, was particularly affected by THM exposure. The risk for men in this intestinal region was significantly elevated, emphasizing the localized impact of these chemicals within the gut. The findings also align with previous studies cited by the researchers, reinforcing the threat posed by THMs in drinking water.¹⁴

For context, THMs form when chlorine, which is used to disinfect water, reacts with natural organic materials present in the water supply. These chemicals are not just byproducts — they possess DNA-damaging properties, leading to mutations that ultimately lead to cancer. “High THM concentrations in drinking water were associated with increased risk of colorectal cancer in men,” the researchers noted.¹⁵

Biologically, THMs are reactive substances. When they enter the body, they interact with cellular components, leading to genotoxicity. This means they damage the genetic information within cells, causing mutations that result in cancer.

Previous animal test studies cited by the researchers have shown that exposure to THMs lead to the formation of aberrant crypts and large-intestine carcinomas, providing a plausible mechanism for how THMs contribute to cancer development in humans.¹⁶