Many types of blue-green algae can produce toxins, and algal blooms can result in high toxin concentrations. Toxic blooms can kill fish and other wildlife. Low dissolved oxygen levels in the waterbody can also take place, especially as the bloom starts to decay. These low oxygen events can also result in fish kill events.
Toxin-forming blue-green algae can also result in serious human health effects. Algal toxins are diverse. Depending on the toxin, they can result in gastrointestinal problems and, in extreme cases, liver damage (hepatoxins). They can affect the nervous system and cause respiratory distress (neurotoxins), or they can cause skin and eye irritation. Animals such as pets can also be negatively impacted by these toxins.
The Florida Department of Environmental Protection (DEP) regularly collects water samples to determine the type of blue-green algae present. If the algae identified are known to produce toxins, additional testing is carried out to determine if toxins are present and the toxin concentration. Water samples collected on April 21 at Lake Wauburg confirmed that the dominant blue-green algae in the lake were Microcystis species and microcystin toxin concentration was 8.4 micrograms/L (µ/L). More recent samples were collected on May 4. The dominant species were unchanged and the toxin concentration results was approximately 1.5 µ/L. Water quality results are available at FloridaDEP.gov/AlgalBloom.
Unfortunately, it is impossible to visually tell if a bloom is producing toxins. For this reason, DEP recommends that individuals and pets stay out of water where algae is visibly present or where water is discolored.
Source: University of Florida's Institute of Food and Agricultural Sciences (UF/IFAS)
Water Resources Regional Specialized Agent
University of Florida IFAS