Harmful algal blooms, or HABs, are caused by the fast development of algae or cyanobacteria, which may injure humans, animals, or the local ecosystem. Harmful algae or cyanobacteria may appear as foam, scum, paint, or mats on the water’s surface and come in a variety of colors. Toxins produced by these blooms may make humans and animals ill. Blooms occur in both fresh water (lakes and rivers) and salt water (oceans and bays).
Individuals are exposed to microcystin and other cyanotoxins when surface scums or water with high toxin concentrations are:
- In contact with the skin
- Inhaled as airborne droplets during relaxation or when watering gardens and lawns
- Swallowed while drinking or recreating
The majority of species of cyanobacteria are unable to create poisons. During blooms, some species can create one or more forms of toxins that may be dangerous to humans or aquatic life, such as neurotoxins (toxins of the nervous system) or hepatotoxins (toxins of the liver).
It is unclear if consuming enough toxins from fish could be hazardous to one’s health, even though there have been no proven reports of cyanotoxin-related health problems associated with eating fish captured during a toxic algal bloom.
