Most lake samples have no cyanobacteria toxins or only trace levels; health alert issued

Posted 8/8/21

As the hot summer continues, FDEP and the South Florida Water Management District continues to take water samples …

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Most lake samples have no cyanobacteria toxins or only trace levels; health alert issued


As the hot summer continues, Florida Department of Environmental Protection (FDEP) and the South Florida Water Management District (SFWMD) continue to take water samples at designated sites as well as anywhere algae is spotted.

Cyanobacteria, commonly called “blue-green algae,” is always present in freshwater lakes, streams and ponds (unless the body of water is sterile). It part of the food chain and important to the ecology. However, high levels of nutrients combined with little water movement and hot temperatures can cause the microscopic algae to reproduce rapidly into a visible mass called a “bloom.” Of the 28 species of cyanobacteria known to be present in the Lake Okeechobee Waterway -- which includes the Caloosahatchee River, Lake O, the St. Lucie Canal and the St. Lucie River -- about 25% are capable of producing toxins, according to the U.S. Geological Survey.

Cyanobacteria capable of producing toxins do not always do so. Because it is not possible to determine if toxins are present without laboratory tests, FDEP advises residents to use caution anywhere algal blooms are visible.

On Aug. 2, 3, 2021, SFWMD staff collected samples from Lake Okeechobee at the following stations. One sample, from the northeast shore, had 13 ppb microcystin. Microcystis aeruginosa was the dominant taxon in all the samples with microcystin levels greater than 1 ppb. The World Health Organization (WHO) considers microcystin levels below 1 ppb to be safe to drink and levels below 8 ppb to be safe for human recreational contact.

Cyanotoxin results are included in parentheses in parts per billion (ppb) following each station name:

• FEBIN (non-detect );
• FEBOUT (trace, 0.31 ppb);
• KISSRO.0 (non-detect);
• LZ2 (non-detect);
• NES191 (2.2 ppb);
• L001 (non-detect);
• NES135 (13 ppb);
• NCENTER (non-detect);
• EASTSHORE (2.0 ppb);
• L004 (1.1 ppb);
• L008 (non-detect);
• L005 (non-detect);
• POLESOUT (non-detect);
• POLESOUT1 (non-detect);
• POLESOUT2 (non-detect);
• POLESOUT3 (non-detect);
• KBARSE (non-detect);
• CLV10A (trace, 0.35 ppb);
• LZ40 (non-detect);
• PALMOUT (non-detect);
• PALMOUT1 (non-detect);
• PALMOUT2 (non-detect);
• PALMOUT3 (non-detect);
• LZ30 (non-detect);
• POLE3S (non-detect);
• RITTAE2 (non-detect);
• LZ25A (non-detect);
• L007 (non-detect);
• L006 (non-detect);
• PELBAY3 (non-detect and
• Pahokee Marina – Boat Ramp (trace, 0.31 ppb).

On Aug. 2, FDEP staff collected samples from Lake Okeechobee (lakeside); and C44 Canal – S308C (canal side). The Lake Okeechobee (lakeside) sample was dominated by Microcystis aeruginosa and had a trace level (0.61 ppb) of microcystins detected. The C44 Canal – S308C (canal side) sample had no dominant algal taxon and no cyanotoxins detected.

On Aug. 3, SFWMD staff collected samples from C43 Canal – S77 (upstream of rim canal) and C43 Canal – S79 (upstream). Neither of the samples had a dominant algal taxon nor cyanotoxins detected.
To report a bloom, call the toll-free hotline at 855-305-3903

The Florida Department of Health advises:
• Do not drink, swim, wade, use personal watercraft, water ski or boat in waters where there is a visible bloom.
• Wash your skin and clothing with soap and water if you have contact with algae, discolored water or smelly water.
• Keep pets away from the area. Waters where there are algae blooms are not safe for animals. Pets and livestock should have a different source of water when algae blooms are present.
• Do not cook or clean dishes with water contaminated by algae blooms. Boiling the water will not eliminate the toxins.
• Eating fillets from healthy fish caught in freshwater lakes experiencing blooms is safe. Rinse fish fillets with tap or bottled water, throw out the guts and cook fish well.
• Do not eat shellfish in waters with algae blooms.

To report fish kills, contact the Florida Fish and Wildlife Research Institute at 1-800-636-0511.

Report symptoms from exposure to a harmful algal bloom or any aquatic toxin to the Florida Poison Information Center, call 1-800-222-1222 to speak to a poison specialist immediately.

Contact your veterinarian if you believe your pet has become ill after consuming or having contact with blue-green algae contaminated water.