Algae bloom toxins in St. Johns River raise concerns of Riverkeeper

Test results of algae samples released Tuesday in a news briefing from the St. Johns Riverkeeper find toxin levels up to 300 times the recreational safe limit.

JACKSONVILLE, Fla. – Test results of algae samples released Tuesday in a news briefing from the St. Johns Riverkeeper find toxin levels up to 300 times the recreational safe limit.

According to the Riverkeeper, the Environmental Protection Agency’s recommended safe limit for recreational water quality is 8 micrograms per liter (µg/L) total microcystins.

“They can cause rash, stomach cramps, nausea and diarrhea…sometimes vomiting,” said Scott Turner, Director of Environmental Health at Florida Department of Health, Duval.

Algae thrive in warm climates. The late summer and early fall are prime time bloom seasons. Turner urges people to be careful in freshwater. Exposure to high algae toxins can cause severe health complications.

“It can affect your liver and nervous system,” Turner said.

Five samples tested by Greenwater Labs contained toxins well in excess of what’s considered safe. The samples were taken at the following locations on Sept. 27 and 28.

  • St. Johns River at St. Vincent’s Hospital (9/27/21) 1,060 ug/L
  • St. Johns at the end of Seminole Road in Avondale (9/27/21) 2,415 ug/L
  • Trout River near Highway 17/Main Street Bridge (9/27/21) 54.8 ug/L
  • St. Johns River at River Road in San Marco (9/28/21) 615 ug/L
  • Mouth of Craig Creek in San Marco (9/28/21) 491 ug/L

Health officials say the public should exercise caution in and around the St. Johns River and those locations.

The St. Johns Riverkeeper noted that its test results differ dramatically from samples recently taken by Florida Department of Environmental Protection at similar locations.

  • St. Johns River at St. Vincent’s Hospital (9/21/21) 3.9 ug/L
  • St. Johns – Canal to Marco Lake in San Marco (9/23/21) 24 ug/L
  • Mouth of Craig Creek (9/23/21) 1.5 ug/L

“Our sample results demonstrate how toxic some of these algae blooms can be,” Lisa Rinaman, the St. Johns Riverkeeper, said in a prepared statement. “Unfortunately, there is no way to determine if a bloom is toxic without testing, so it is best to avoid contact and exposure with all algae outbreaks you may encounter.”

These readings by the Riverkeeper are the highest since 2013. That year, one sample came back at 4,350 ug/L, and the Florida Health Department told people to stay off the river.

This is concerning to resident Roy Graham who said he sees algae on the river often.

“I’m afraid for people too and their health. Some people get sick and everything,” Graham said.

It’s the opposite for fisherman Bennie Davis. He’s not worried about algae bloom toxin exposure at all.

“I’ve fished in lakes that wasn’t so clean and nothing has ever happened to me,” Davis said.

Eating fish from algae bloom water is safe when cleaned and cooked but eating shellfish is not.

  • 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 algae blooms are present 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.

About the Authors:

This native of the Big Apple joined the News4Jax team in July 2021.