Where It Comes From
Forms during chlorination of water with natural organic matter; also occurs in chlorinated swimming pools and some industrial processes [1][2].
How You Are Exposed
Mainly by drinking tap water; smaller amounts from inhalation/skin contact during bathing or swimming; very limited workplace exposure in specialized labs/industry [1][2].
Why It Matters
Can cause liver and nerve effects; long-term high exposures caused cancers in laboratory animals; human cancer evidence is limited/uncertain. Regulated as part of HAA5 (sum limit 60 µg/L in U.S. public water) [1][2][3].
Who Is at Risk
People who drink a lot of tap water where HAA levels are high; infants (especially formula prepared with tap water), pregnant people, and those with liver disease [1][2].
How to Lower Your Exposure
Check your water utility’s Consumer Confidence Report; use a home filter certified to reduce haloacetic acids (activated carbon or reverse osmosis); use cold water for drinking/cooking; avoid swallowing pool water and improve pool ventilation [2][3].
References
- [1]ATSDR. Toxicological Profile for Dichloroacetic Acid (DCA). Agency for Toxic Substances and Disease Registry.
- [2]WHO. Dichloroacetic Acid in Drinking-water: Background document for development of WHO Guidelines for Drinking-water Quality. World Health Organization.
- [3]EPA. National Primary Drinking Water Regulations: Haloacetic Acids (HAA5/HAA9) and Stage 2 Disinfectants/Disinfection Byproducts Rule. U.S. Environmental Protection Agency.
- [4]EPA IRIS. Dichloroacetic acid (CASRN 79-43-6). Integrated Risk Information System, U.S. Environmental Protection Agency.