Toxins in Caloosahatchee exceed EPA recreational threshold
Water testing results have revealed the cyanobacteria in the Caloosahatchee is releasing toxins.
Cyanobacteria, or blue-green algae, was detected in the last couple of weeks.
John Cassani, the Calusa Waterkeeper, received results June 28 from water tests he conducted June 26 and sent off. Greenwater Laboratories in Palatka, Florida, analyzed the tests, according to a Calusa Waterkeeper Facebook post. The five test samples taken from State Road 79 East to Baron Park in LaBelle all came back with detected microcystin, the toxin released by blue-green algae. Results ranged from 172 to 1,970 nanograms per milliliter. A sample taken June 26 at the WP Franklin Lock Recreational Area tallied 463.34 micgrograms per liter.
According to a 2017 fact sheet, the U.S. Environmental Protection Agency’s recommended recreational threshold is 4 micrograms per liter; a microgram is 1,000 nanograms. Nanograms per milliliter is an equivalent measurement of micrograms per liter.
This algae is an indicator of degraded water quality, said Rae Ann Wessel, Director of Natural Policy for the Sanibel-Captiva Conservation Foundation.
The problem has been growing since last week as the algae continues to bloom in bright green, discoloring the typically dark river.
On Tuesday, the Florida Department of Health for Lee County issued a warning about coming in contact with algae blooms. Then Thursday, Lee County issued a water warning telling residents the cyanobacteria had tested positive for toxins. According to a DEP report, results reported June 28 show 3.3 micrograms per liter at Moorehaven, where the river meets Lake Okeechobee, and 25.41 micrograms per liter at South Olga Road.
Notes from June 27 in a sample site called Orange River Tree Farm stated the “algal bloom expanded from previous visit 24hrs prior.” This site reported 6.6 micrograms per liter of microcystin present June 26.
The Department of Health has a specific health advisory warning for the Alva Boat Ramp, the Davis Boat Ramp, and the Franklin Locks.
According to the EPA’s guidelines and recommendations for harmful algal blooms, several states have implemented harmful algal bloom response guidelines, outlining local response to blooms. Florida is not on the list.?The algal bloom now covers a majority of Lake Okeechobee and has been moving downstream for a stretch of 40 miles of the 70-mile river. A post on the Waterkeeper Facebook page shows a line of algal bloom near the powerplant along the river in Fort Myers, and said smaller patches of blooms are visible near Centennial Park.
“Centennial Park is not very extensive compared to upstream,” Cassani said. “But it’s likely to continue to move downstream.”?Certain weather conditions, like cloud days, start killing the cyanobacteria. But that’s when they release even more toxin, Cassani said. The freshwater releases from Lake Okeechobee will continue to push the bloom further downstream. In an email yesterday, the U.S. Army Corps of Engineers announced a pause to discharges to the St. Lucie River for nine days. The releases to the Caloosahatchee will continue at 3,000 cubic feet per second, but the water will be released in a “pulse” pattern by varying the flows. But, the lake rose to 14.10 feet this week from 14 feet last week.
“We will pause discharges to the east for a nine-day period to allow additional tidal flushing to take place within the estuary,” said Lt. Col. Jennifer Reynolds, Jacksonville District Deputy Commander for South Florida. “However, with the lake rising, we anticipate having to resume flows at previous rates.”
Cyanobacteria is a mostly freshwater organism but it can tolerate brackish conditions. With the releases pushing freshwater further downstream, it will continue to creep down the Caloosahatchee into Fort Myers, Cassani said.
The Waterkeeper page has been inundated with residents on the river reporting what they’re seeing: bright green sludge in their river. Tuesday, the page posted a photo from Alva, where the algae has started to smell and coagulate in a blue-colored patch, from where the organism gets its name.
“We try to use that Facebook platform to share information,” Cassani said.
Cyanobacteria toxins create a situation called hypoxia, when the oxygen levels in the water are depleted, Cassani said. It poses a threat to marine life which depends on oxygen in the water.
Boating through blooms can release more of the toxins, the county warning states.
Blue-green algal blooms should be reported at floridadep.gov/dear/algal-bloom.