What type of contaminants can trihalogen methanes (THMs) be associated with?

Trihalomethanes (THMs) are a group of chemical compounds that are formed when chlorine and other disinfectants used in water treatment react with organic matter present in the source water. Common sources of organic matter in water can include natural materials such as decomposing leaves, algae, and other plant debris.

THMs consist of one carbon atom bound to three halogen atoms (usually chlorine, bromine, or fluorine) and are primarily a result of the chlorination process, which is a common method used to disinfect drinking water. Because THMs originate from the reaction between disinfectants and organic materials, they are classified as organic compounds. The presence of these substances in drinking water is a concern due to potential health risks associated with long-term exposure.

In contrast, the other options refer to different types of contaminants. Metals refer to inorganic substances found in water, while bacteria and pathogens are biological contaminants that may not be directly associated with the formation of THMs. Therefore, organic compounds are the correct classification for the contaminants associated with trihalomethanes.