Airborne Cyanobacterial Toxins Identified in Southwest Florida, Linked to Neurodegenerative Risks

Cyanobacteria, a blue-green algae is known to have played an ancient role in establishing Earth's atmosphere. They love warm temperatures, lots of sunlight and slow-moving water. Florida's year-round climate provides all of this and more. When rivers, lakes and estuaries are loaded with excess nitrogen and phosphorus, often due to agricultural runoff and improperly treated sewage, cyanobacterial populations can explode, releasing toxins into the environment that can damage human health. In 2025, nonprofit Brain Chemistry Labs in Jackson, Wyoming partnered with neurologists and oceanographers at the Miller School of Medicine in Miami, marine biologists at Hubbs-SeaWorld Research Institute and the Blue World Research Institute to announce that the beached dolphins in Florida's Indian River Lagoon showed signs of Alzheimer's disease. Their brains had high concentrations of the neurotoxin 2,4-DAB, an isomer of BMAA produced by cyanobacteria. Now, partnering with nonprofit Calusa Waterkeeper in Fort Myers, Florida, the Wyoming scientists announced that they have identified airborne cyanobacterial toxins collected in special detectors placed in different locations in Southwest Florida. All of the samples contained the neurotoxin 2,4-DAB, the same cyanobacterial toxin found in the dolphins.

People may be chronically exposed to low concentrations of cyanobacterial toxins

"Data obtained from ADAM [Airborne Detection for Algae Monitoring] airborne detectors indicate that people may be chronically exposed to low concentrations of cyanobacterial toxins and that further assessment is required to help protect human health," the scientists announced in a paper published in the journal Toxins. "These data suggest that you don't need to be close to toxic blooms to be exposed through breathing. We continue to find cyanobacterial toxins in the air, as in our study of dust blown from the exposed lakebed of the Great Salt Lake in Utah," said lead scientist Dr James Metcalf. "Our research has shown that chronic low-level exposure to cyanobacterial toxins is a risk factor for ALS and potentially other neurodegenerative diseases," adds Dr. Paul Cox, Brain Chemistry Labs executive director. The Wyoming team researched a dramatic increase in ALS among veterans, suggesting that inhalation of cyanobacteria from desert dust in Kuwait and Iraq caused the spike in ALS 10 years after their deployment to Operation Desert Storm in 1993. Previously, Brain Chemistry Labs has quantified high levels of cyanobacterial toxins in the Caoosahatchee and St Lucie rivers, resulting from the release of cyanobacterial-laden waters from Lake Okeechobee.

Individuals living close to lakes and estuaries with cyanobacterial blooms are at a significantly higher risk of ALS

Research by neurologist Elijah Stommel at Dartmouth Medical School shows that individuals living close to lakes and estuaries with cyanobacterial blooms are at a significantly higher risk of ALS. Consumption of contaminated food and water has been deemed the likely route of exposure by researchers. "Even though we can avoid contaminated food and water, preventing exposure through breathing is far more difficult," Metcalf added. Cyanobacteria often grow in warm, polluted water bodies. When the blooms die or get chopped up by boats or waves, their cells burst open and the toxins attach to water droplets or dust that travel further than just the shoreline, as mentioned in the research. Breathing in the toxins can cause coughing, wheezing, sore throat, breathing problems and long-term brain health risks as well. It is important to avoid the water and keep a distance if you smell a strong, foul odour near lakes or canals.