Trihalomethanes (THMs) are

Trihalomethanes (THMs) are

• A. compounds that form from the reaction of chlorine or bromine with organic matter in drinking water
• B. compounds from the reduction of nitrates
• C. compounds formed by reaction of ozone with organics
• D. compounds formed by chlorine reacting with metals

Answer: (A)

Trihalomethanes are formed when chlorine or bromine used to disinfect drinking water reacts with natural organic matter in the water. These disinfection byproducts arise during chlorination or bromination and include compounds like chloroform; their formation depends on how much organic material is present, the chlorine dose and contact time, temperature, and bromide in the water. They are not produced by reducing nitrates, by ozone reacting with organics (which yields different byproducts), or by chlorine reacting with metals (which forms inorganic chlorides). Understanding this helps explain why water utilities try to minimize organic matter before disinfection or use alternative methods to limit THM formation.

Trihalomethanes are formed when chlorine or bromine used to disinfect drinking water reacts with natural organic matter in the water. These disinfection byproducts arise during chlorination or bromination and include compounds like chloroform; their formation depends on how much organic material is present, the chlorine dose and contact time, temperature, and bromide in the water. They are not produced by reducing nitrates, by ozone reacting with organics (which yields different byproducts), or by chlorine reacting with metals (which forms inorganic chlorides). Understanding this helps explain why water utilities try to minimize organic matter before disinfection or use alternative methods to limit THM formation.