Where It Comes From
Produced by cyanobacteria such as Dolichospermum (Anabaena), Aphanizomenon, and Planktothrix during blooms; warm, nutrient‑rich water increases risk [1][2].
How You Are Exposed
Swallowing contaminated water, inhaling spray during recreation, eating contaminated fish or shellfish, or drinking inadequately treated water [1][3].
Why It Matters
Symptoms can start within minutes to hours—tingling, muscle twitching, weakness, drooling, breathing trouble, seizures—and can be fatal; no antidote [1][2].
Who Is at Risk
Young children, people using untreated surface water, swimmers and boaters, people with asthma, and pets (especially dogs) [2][3].
How to Lower Your Exposure
Heed bloom advisories; avoid discolored water or surface scums; keep pets out and rinse after contact; don’t boil; use certified treatment (e.g., activated carbon/oxidation) or another source; follow fish advisories [1][2][3].
References
- [1]World Health Organization (WHO). Anatoxin-a and analogues in drinking-water: Background document for development of WHO Guidelines for drinking-water quality. 2020/2021.
- [2]U.S. Environmental Protection Agency (EPA). Recommendations for Public Water Systems to Manage Cyanotoxins in Drinking Water. EPA 815-R-15-100. 2015 (updated).
- [3]Centers for Disease Control and Prevention (CDC). Harmful Algal Blooms (HABs): Protect Yourself and Your Pets. Updated 2023.