Which of the following is a disinfection byproduct?

Trihalomethanes (THMs) are classified as disinfection byproducts because they are formed when chlorine or chlorinated compounds are used for disinfection in water treatment processes, particularly when organic matter is present in the water. When chlorine reacts with natural organic materials, it can create several types of THMs, such as chloroform, bromoform, bromodichloromethane, and chlorodibromomethane. The formation of these compounds is a significant concern for water quality, as some THMs have been identified as potential health risks.

Chloramine, although a disinfectant used in water treatment, is not classified as a disinfection byproduct itself. Rather, it is an alternative to chlorine for disinfecting water. Fluoride is commonly added to drinking water for dental health benefits and does not fall under the category of disinfection byproducts. Chlorine dioxide is also a disinfectant and, like chloramine, is utilized to treat water but does not directly refer to a byproduct of disinfection processes. Therefore, the most accurate option that corresponds to the criteria for disinfection byproducts is THMs.