Most cyanotoxins fall into one of four categories:
- Neurotoxins — Common forms are anatoxins and saxitoxins. These toxins affect the nervous system.
- Hepatotoxins — Common forms are microcystins, cylindrospermopsin and nodularin. These toxins affect the liver and may have a cumulative effect.
- Dermatotoxins — toxins that may cause dermatological rashes, sometimes called swimmers itch.
- Endotoxins — toxins that may cause respiratory and gastrointestinal illness.
Research to date, based only on the analysis of their chemical structures, suggests that all of the currently known toxins are oxidizable. In other words, free oxygen could be used to cleave and biologically “disarm” the toxins. At the present time, there are no efficacy studies completed to formally substantiate the theory, but studies are forthcoming. One of the most common and dangerous hepatotoxins found in freshwater environments, Microcystin-LR, is now commercially available for testing.
Toxins That Can Be Deadly
For decades now, animal kills near ponds and lakes have been attributed to Microcystin and other toxins associated with algal blooms. More recently, human deaths and illnesses in Brazil were attributed to the Microcystin toxin. Most recently, a neurotoxin, Anatoxin-a, was eventually cited as the cause of a mysterious death of a teen in Wisconsin.
Here is a partial listing of some common cyanobacteria genera and the associated toxins they may produce: