Chloronitramide anion is a decomposition product of inorganic chloramines

Inorganic chloramines are commonly used drinking water disinfectants intended to safeguard public health and curb regulated disinfection by-product formation. However, inorganic chloramines themselves produce by-products that are poorly characterized. We report chloronitramide anion (Cl–N–NO 2 − ) as a previously unidentified end product of inorganic chloramine decomposition. Analysis of chloraminated US drinking waters found Cl–N–NO 2 − in all samples tested ( n = 40), with a median concentration of 23 micrograms per liter and first and third quartiles of 1.3 and 92 micrograms per liter, respectively. Cl–N–NO 2 − warrants occurrence and toxicity studies in chloraminated water systems that serve more than 113 million people in the US alone.