Which by-product group is formed from the reaction of chlorine with organic matter in drinking water?

Which by-product group is formed from the reaction of chlorine with organic matter in drinking water?

• A. THMs
• B. Dioxins
• C. PCBs
• D. Nitrates

Answer: (A)

Chlorination of drinking water can produce disinfection by-products when natural organic matter is present. The most common group formed in this situation is trihalomethanes (THMs), which arise when chlorine reacts with organic carbon in the water. THMs include compounds like chloroform and other brominated variants, and they’re the classic by-products looked for in monitoring disinfection by-product formation. The other options aren’t produced by this chlorine–organic matter reaction: dioxins and PCBs are industrial pollutants associated with specific processes, not typical drinking-water chlorination; nitrates come from nitrogen sources in the water, not from chlorine reacting with organics.

Chlorination of drinking water can produce disinfection by-products when natural organic matter is present. The most common group formed in this situation is trihalomethanes (THMs), which arise when chlorine reacts with organic carbon in the water. THMs include compounds like chloroform and other brominated variants, and they’re the classic by-products looked for in monitoring disinfection by-product formation. The other options aren’t produced by this chlorine–organic matter reaction: dioxins and PCBs are industrial pollutants associated with specific processes, not typical drinking-water chlorination; nitrates come from nitrogen sources in the water, not from chlorine reacting with organics.