Where It Comes From
Forms when disinfectants react with natural organic matter and bromide in water; found in chlorinated drinking water, pools, and wastewater; regulated as part of total trihalomethanes (TTHMs) [1][2].
How You Are Exposed
Drinking tap water; breathing vapors during hot showers/baths or dishwashing; skin contact while bathing or swimming; some workplace exposures (e.g., water treatment) [1][2].
Why It Matters
At higher or long-term levels, studies link DBCM to liver, kidney, and reproductive effects; cancer seen in animals. EPA and WHO set limits/guidelines to reduce risk [1][2][3].
Who Is at Risk
Pregnant people and infants; people with liver or kidney disease; those who drink a lot of tap water, take long/hot showers, or swim often; water plant workers [1][2].
How to Lower Your Exposure
Use a certified activated carbon or reverse osmosis filter for THMs; ventilate bathrooms and take shorter, cooler showers; review your water quality report; choose well-maintained, well-ventilated pools [1][2][3].
References
- [1]ATSDR. ToxFAQs for Disinfection By-products: Trihalomethanes (chloroform, bromoform, bromodichloromethane, dibromochloromethane), 2015/2021.
- [2]U.S. EPA. Basic Information about Disinfection Byproducts in Drinking Water; National Primary Drinking Water Regulations (TTHM MCL).
- [3]WHO. Guidelines for Drinking-water Quality: Disinfection by-products including trihalomethanes.