What is the disinfection byproduct often formed when chlorine reacts with organic matter in water?

The formation of disinfection byproducts is a significant concern in water treatment, especially when chlorine is used as a primary disinfectant. Among the various byproducts formed during this process, trihalomethanes (THMs) are particularly notable. THMs are generated when chlorine reacts with naturally occurring organic materials in the water, such as humic and fulvic acids. This reaction leads to the creation of compounds like chloroform, bromodichloromethane, dibromochloromethane, and bromoform, all of which fall under the category of THMs.

The key reason why trihalomethanes are recognized as the correct answer lies in their prevalence and significance as environmental pollutants. Regulatory agencies monitor and regulate their levels in drinking water due to their potential health risks.

In contrast, while chloramines are another type of disinfection byproduct that can form when chlorine reacts with ammonia, they differ fundamentally from THMs in terms of their chemical composition and the conditions under which they form. Chlorine dioxide, although used for disinfection, does not typically lead to the formation of trihalomethanes, and brominated compounds pertain to a different group of disinfection byproducts that may also form but are