‘Phantom chemical’ found in drinking water is new to science

Tap drinking water in developed countries is quite clean, but there may still be invisible contaminants lurking in it. One mysterious “ghost chemical” has been plaguing drinking water for decades, and now researchers have identified it – and discovered it’s completely new to science.

Water is often chlorinated to disinfect it, which has proven effective in killing most waterborne pathogens, but it can create byproducts that are harmful to human health. A related compound, chloramine, was found to not only produce fewer of these byproducts, but also last longer. Thus, it is widely used in the US and some other regions.

However, chloramine is not without its own by-products. It has long been established that chemical analysis shows that five to 10% of the expected nitrogen disappears, locked up in some other molecule that has eluded direct identification for decades.

Now scientists have finally identified this strange “phantom chemical.” It is called the chlornitramide anion and is a negatively charged molecule consisting of one chlorine atom, two nitrogen atoms and two oxygen atoms.

The researchers synthesized and isolated the chemical, then analyzed it using high-resolution mass spectrometry and nuclear magnetic resonance spectroscopy to reveal its properties.

Oliver Jones

They then measured the concentrations of these anions in various US water systems treated with chloramines. They found it at levels of up to 100 micrograms per liter, exceeding the regulatory limits of 60 to 80 micrograms per liter that are typically allowed for disinfection byproducts.

Direct toxicology studies of the compound have not yet been conducted, but the team says analyzes indicate that the chlornitramide anion is not entirely harmless.

“I agree that toxicological studies of this anion would be useful now that we know its nature, but I’m not too worried about my tap water,” says Oliver Jones, professor of chemistry at RMIT. “The compound in question is not recently discovered, but simply redefined. Its presence in some (not all) drinking waters has been known for over 30 years.”

“The question is whether this substance is toxic in the quantities we are exposed to,” Jones continues. “I think the answer here is probably no. This study tested only 40 samples, which is not sufficient to be representative of all tap water in the United States, and the concentrations of chlornitramide in most samples were well below regulatory limits for most disinfection byproducts.”

Regardless of whether it is dangerous or not, identifying the mystery chemical after all this time is an important step. The study was published in the journal Science.

Source: University of Arkansas via Scimex.