Where It Comes From
Produced by bloom‑forming cyanobacteria in lakes, reservoirs, and slow‑moving rivers; one of many microcystin variants [1].
How You Are Exposed
Drinking contaminated water, swallowing water while swimming, breathing water spray during recreation, and eating fish caught from bloom‑affected waters [2][3].
Why It Matters
Causes nausea, vomiting, diarrhea, abdominal pain, and liver injury; severe poisonings can be life‑threatening. Long‑term exposure raises concern for liver cancer; microcystin‑LR is classified by IARC as possibly carcinogenic (Group 2B) [1][4].
Who Is at Risk
Infants/children, pregnant people, those with liver disease, people on dialysis, and frequent users of bloom waters (swimmers, boaters, anglers); pets are very vulnerable [1][2][3].
How to Lower Your Exposure
Follow bloom advisories; avoid scummy/discolored water; don’t boil contaminated water (it can concentrate toxins); use safe alternative water or certified treatment (activated carbon or reverse osmosis); rinse fish fillets and discard guts/organs; keep pets away from blooms [2][3].