PAHOKEE – The Pahokee Marina continues to be plagued with toxic cyanobacterial blooms as the summer heats up.

Cyanobacteria (commonly called blue-green algae) are part of Lake Okeechobee's natural ecosystem. Most of the time they are not visible to the human eye. Under the right conditions – hot weather, lack of water movement and available phosphorus and nitrogen in the water – the microscopic cyanobacteria can reproduce rapidly into a visible “bloom.” According to the U.S. Geological Survey about 25% of the species of blue-green algae in the Lake Okeechobee Waterway are capable of producing toxins, but do not always produce toxins. Microcystis aeruginosa, the dominant species in the Pahokee Marina, can produce the microcystin toxin.

On May 30, the Florida Department of Environmental Protection described a bloom at the marina as “BGA (blue-green algae) dispersed evenly throughout the water column in high density at the sample site. Strong odor and dense mats. BGA floating on the surface of water with visible striations,” The lab test showed a microcystin toxin level of 63 parts per billion (ppb).

The World Health Organization (WHO) and Environmental Protection Agency (EPA) consider microcystin toxin levels above 1.0 ppb to be unsafe for drinking water and levels above 8.0 ppb to be unsafe for human recreational contact (swimming).

The South Florida Water Management District (SFWMD) installed a pump to increase water circulation and had some success treating the recurring blooms with algaecide.

In a June 5 email, Randy Smith with SFWMD explained: “The district provided assistance to the City of Pahokee for the blue-green algae at the Pahokee Marina. In the past week and a half, District contractors applied Lake Guard Oxy during five treatment sessions. The District also installed a temporary pump to help circulate water.

“SFWMD uses an innovative technology called Lake Guard Oxy, which is hydrogen peroxide (H2O2) pellets, to treat algal blooms. This is a science-based mitigation measure that uses oxygen in the water column to break down the blue-green algal cells and the toxins they produce.

"The granular algaecide product floats on top of the water and utilizes a time release formulation of its active ingredient (hydrogen peroxide - H2O2) when applied to water. Hydrogen peroxide acts as an oxidizing agent on organic matter and targets nuisance cyanobacteria. Once the hydrogen peroxide reacts with the harmful blue-green algae, it breaks down into oxygen and water within hours which does not impact beneficial algae or other native wildlife and plant life. It is important to remember that harmful algal blooms have negative impacts to wildlife and the environment, and treatment mitigates these impacts.

“The product is applied per the manufacturer’s recommendation and in accordance with their EPA approved label.

“Treatment of algal blooms does not lift or change county jealth department recommendations/advisories. The public should follow the advice of county health departments when determining where to swim or recreate on waterways.

Water samples at four sites at the Pahokee Marina in late May and early June show microcystin toxin levels varying.

Pahokee Marina Site 1:
• May 22 sample was 6.8 ppb.
• May 25 sample was 3.0 ppb.
• May 28 sample had 2.2 ppb.
• June 1 sample was 21 ppb.
• June 5 sample was 0.39 ppb.

Pahokee Marina Site 2:
• May 25 sample was 1.3 ppb.
• May 30 sample was 63 ppb.
• June 1 sample was 23 ppb.
• June 3 sample was 21 ppb.

Pahokee Marina Site 3:
• May 25 sample was 1.5 ppb.
• May 30 sample was 30 ppb.
• June 1 sample was 8.5 ppb.
• June 6 sample was 3.9 ppb.

Pahokee Marina Site 4:
• May 25 sample was 9.4 ppb.
• May 28 sample was 1.2 ppb.
• May 30 sample was 12 ppb.
• June 1 sample was 12 ppb.