Where It Comes From
Chlorinated or chloraminated drinking-water systems, especially where source water contains bromide (coastal/brackish influence); also forms in pools and hot tubs [1][2].
How You Are Exposed
Mainly by drinking tap water and beverages/foods made with it; infants fed formula mixed with tap water may have higher intake. Skin and air exposure are minor for HAAs [2].
Why It Matters
EPA limits HAA5 at 60 µg/L; the brominated HAAs (HAA6BR) are not individually regulated but are monitored within HAA9 nationally. Brominated HAAs tend to be more toxic in lab tests [2][3][4].
Who Is at Risk
People who drink a lot of tap water, pregnant people and infants, and communities with bromide‑affected supplies; dialysis patients if water treatment fails [1][2].
How to Lower Your Exposure
Check your water utility’s Consumer Confidence Report; consider point‑of‑use filters certified for HAA reduction (NSF/ANSI 53 carbon or 58 reverse osmosis), or use alternative water for mixing infant formula [5].
References
- [1]U.S. EPA. Disinfection Byproducts in Drinking Water. https://www.epa.gov/dwreginfo/drinking-water-disinfection-disinfection-byproducts
- [2]WHO. Guidelines for Drinking‑water Quality, Disinfectants and Disinfection By‑products. https://www.who.int/publications/i/item/9789241549950
- [3]U.S. EPA. National Primary Drinking Water Regulations: Stage 2 Disinfectants and Disinfection Byproducts Rule (HAA5 MCL). https://www.epa.gov/dwreginfo/stage-2-disinfectants-and-disinfection-byproducts-rule
- [4]U.S. EPA. Fifth Unregulated Contaminant Monitoring Rule (UCMR 5): HAA9. https://www.epa.gov/dwucmr/fifth-unregulated-contaminant-monitoring-rule
- [5]CDC. Selecting a Home Water Treatment System. https://www.cdc.gov/healthy-water/drinking/home-water-treatment/selection.html