Which compound can be a disinfection byproduct if chlorine is used as a disinfectant?

The presence of chlorination in water treatment introduces the potential for the formation of disinfection byproducts, particularly when organic matter is present in the water. Trihalomethanes are a category of disinfection byproducts formed when chlorine reacts with natural organic materials in water, such as humic and fulvic acids. This reaction can lead to the formation of compounds like chloroform, bromoform, bromodichloromethane, and dibromochloromethane, all classified as trihalomethanes.

These byproducts are significant because they pose a potential health risk if consumed in high concentrations over extended periods. Regulatory agencies closely monitor the levels of trihalomethanes in drinking water due to their potential carcinogenic effects.

The other choices provided do not typically form as byproducts of chlorination. For instance, trichloroethylene is primarily an industrial solvent and not a byproduct related to water disinfection. Formaldehyde can occur under certain conditions but is not a principal byproduct of chlorine disinfection. Carbon dioxide, while a product of many biological and chemical processes, is not a byproduct of chlorine disinfection in this context. Thus, trihalomethanes are the primary concern regarding hazardous