What is the primary source of trihalomethanes (THMs) in drinking water?

Trihalomethanes (THMs) are primarily formed through the reaction of chlorine compounds, commonly used as disinfectants in water treatment, with organic matter present in the water. When chlorine is added to drinking water, it reacts with organic materials such as decayed vegetation, which can be found naturally in surface waters. This process can result in the formation of THMs, including compounds such as chloroform, bromoform, bromodichloromethane, anddibromochloromethane.

Understanding the formation of THMs is crucial because they are regulated in drinking water due to potential health risks associated with long-term exposure. Reducing the levels of organic matter in water before chlorination can help minimize THM formation, which illustrates the importance of proper water treatment practices in safeguarding public health.