Which disinfectant can lead to the formation of Trihalomethanes (THMs)?

The correct answer identifies free chlorine as the disinfectant that can lead to the formation of Trihalomethanes (THMs). When free chlorine is used as a disinfectant in water treatment processes, especially in the presence of organic matter, it can react with naturally occurring organic substances in the water. This reaction can produce byproducts, specifically THMs, which are a group of chemical compounds that can pose health risks if consumed in large quantities over time.

The potential for THMs to form makes understanding and monitoring water disinfection practices critical for maintaining safe drinking water standards. Free chlorine is widely used due to its powerful disinfectant properties, but it is important for water treatment facilities to balance effective pathogen control while minimizing the formation of harmful disinfection byproducts like THMs.

Other disinfectants listed have different reactions. For instance, chloramine, while stable and less prone to forming THMs compared to free chlorine, can lead to a different set of byproducts. Ozone is a strong oxidant that, although it does not lead to THM formation directly, can create other potentially harmful byproducts. UV light, on the other hand, does not produce THMs as it works by inactivating pathogens through a different mechanism without introducing any chemical residues