Where It Comes From
Byproduct of ozonated drinking water and some bottled waters; residues from potassium bromate in baking where still permitted [1][2].
How You Are Exposed
Drinking tap water from ozonated systems, bottled water treated with ozone, occasionally certain breads; workplace handling of bromate salts [1][2][3].
Why It Matters
EPA’s drinking water limit is 10 ppb; WHO’s guideline is 10 µg/L. Potassium bromate is classified by IARC as possibly carcinogenic to humans (Group 2B); high doses can damage kidneys and hearing [1][2][3].
Who Is at Risk
People in communities using ozone with high natural bromide in source water, heavy consumers of ozonated bottled water, and certain workers (water treatment, baking where used) [1][2].
How to Lower Your Exposure
Check your water utility’s Consumer Confidence Report for bromate; consider a certified reverse osmosis filter; choose breads made without potassium bromate; store bottled water away from heat/light and use promptly [1][2].
References
- [1]U.S. EPA. National Primary Drinking Water Regulations – Bromate (MCL 0.010 mg/L). https://www.epa.gov/ground-water-and-drinking-water/national-primary-drinking-water-regulations
- [2]WHO. Bromate in Drinking-water: Background document for development of WHO Guidelines for Drinking-water Quality. https://www.who.int/publications
- [3]IARC Monographs, Volume 73 (1999). Potassium bromate (Group 2B). https://monographs.iarc.who.int/