OKEECHOBEE -- On March 16, the Florida Department of Environmental Protection issued a Blue Green Algae Bloom Alert for Lake Okeechobee in response to trace levels of microcystin toxins found in a Lake Okeechobee water sample taken on March 12.

 The alert referenced sample site LZ2, which is near the Clif Betts Lakeside Recreation Area, commonly called “Lock 7” by Okeechobee residents.

According to the Florida Department of Environmental Protection (FDEP), the March 12 sample from the LZ2 site had 0.33 parts per billion (ppb) cyanotoxins detected. The EPA considers levels below 1.0 ppb to be safe for drinking water, and levels below 8.0 ppb to be safe for human recreational contact (such as swimming).

Clint Sperber, with the Florida Department of Health, said alerts are issued anytime toxins are found, even in trace levels.

The South Florida Water Management District and Florida FDEP regularly sample water from 32 sites on Lake Okeechobee as well as other sites on the Lake Okeechobee Waterway, which includes the Caloosahatchee River, Lake Okeechobee, the St. Lucie Canal and the St. Lucie River. In addition, FDEP samples water anywhere an algal bloom is reported. To report a bloom to FDEP, call the toll-free hotline at 855-305-3903.

On March 12 and March 13, SFWMD staff collected eight routine monitoring samples from Lake Okeechobee:

KISSR0.0: No dominant algae species found; no cyanotoxins detected.

LZ2: Microcystis aeruginosa found; trace level (0.33 ppb) microcystins detected.

L005: Dolichospermum circinale found; no cyanotoxins detected.

POLESOUT: Microcystis aeruginosa found; no cyanotoxins detected.

CLV10A: No dominant algae species found; no microcystins detected. Results for saxitoxins and anatoxin-a pending.

PALMOUT: Microcystis aeruginosa found; trace level (0.26 ppb) microcystins detected. Results for saxitoxins and anatoxin-a pending.

LZ30: Microcystis aeruginosa found; no microcystins detected. Results for saxitoxins and anatoxin-a pending.

RITTAE2: Microcystis aeruginosa found; no microcystins detected. Results for saxitoxins and anatoxin-a pending.

Microcystis aeruginosa is a species of freshwater cyanobacteria. These cyanobacteria feed off phosphorus and nitrogen available in the water.  Unlike some other cyanobacteria (such as Anabaena), Microcystis cannot “fix” nitrogen from the air. Under certain conditions, Microcystis may produce toxins. Scientists have not determined exactly what causes cyanobacteria to produce toxins, but high levels of nitrogen in the water may be a factor.

The Florida Department of Health advises the public to use caution in any water where visible algae are present. You cannot tell what kind of algae are present or if toxins are present without laboratory testing. Of the 28 species of cyanobacteria (commonly called blue green algae) documented by U.S. Geological Survey in the Lake Okeechobee Waterway, about 25% are capable of producing toxins. Those capable of producing toxins do not always do so.

If high levels of microcystins are found, SFWMD staff treat affected areas with an alagecide to break up the bloom. The low toxin levels found  on March 12 did not require treatment.

If you see an algae bloom, the Health Department 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 or discolored 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.

Cyanobacteria and algae are part of the natural ecosystem and are present in all lakes, streams, ponds, canals and waterways. Most of the time, these microscopic organisms are not visible to the human eye. Under certain conditions they can reproduce rapidly into a visible “bloom.”  Some environmental factors that contribute to algae blooms are sunny days, warm water temperatures, still water conditions and excess nutrients. Blooms can appear year-round but are more frequent in summer.

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.

If you have other health questions or concerns about blue-green algae blooms,  call the Florida Department of Health in Okeechobee County at 772-873-4927.

On rare occasions, algae blooms are connected to fish kills, according to the Florida Fish and Wildlife Conservation Commission. This is not due to toxins. Lack of sunlight on a cloudy day may cause algae to die off, which causes oxygen to be depleted from the  water. If fish are under a large algae bloom at this time and do not swim out of the area quickly enough, they can die from lack of oxygen. To report fish kills, contact the Florida Fish and Wildlife Research Institute at 1-800-636-0511.

FDEP tested algae blooms in other Florida lakes the same week. The highest toxin levels were found in Lake Pearl in Orange County, whereMicrocystis aeruginosa and Pseudanabaena mucicola were co-dominant and 6.2 ppb microcystins detected.