What substance is formed when organics in surface water combine with halogens?

When organics in surface water react with halogens, a specific type of substance known as trihalomethanes is formed. This reaction typically occurs when chlorine or chlorinated compounds are used for disinfection purposes in water treatment processes. The presence of organic matter, which includes natural materials such as decaying plant and animal material, leads to the formation of these compounds during the chlorination process.

Trihalomethanes are of concern due to their potential health effects when consumed in drinking water, prompting guidelines and regulations for their levels. Their formation is a key aspect of water treatment chemistry, emphasizing the need for effective management of organic material in water sources to minimize their production. Understanding this process helps in developing strategies for water treatment and ensuring public health safety regarding drinking water quality.