Polski
Science, Issue 7/2026
Cyanobacterial toxins are present in the air. A new tool helps assess the risk
Aug
Exposure to cyanobacterial toxins is typically associated with swimming in lakes experiencing algal blooms or consuming contaminated water. However, a growing body of research indicates that these dangerous compounds may also be present in the air. Scientists in the United States have developed a portable device to detect cyanobacterial toxins in aerosols and investigated whether their presence in the air corresponds to what is happening in the water. The results, published in the journal *Toxins*, show that even with small blooms, a threat can also arise in the atmosphere.
Why are cyanobacterial toxins in the air a cause for concern?
Cyanobacteria produce many toxic compounds that can have hepatotoxic, neurotoxic, and cytotoxic effects. Previous studies have focused on exposure through contact with drinking water, water-based recreation, or the consumption of contaminated fish and seafood. However, researchers point out that inhaling aerosols formed on the surface of bodies of water can be equally harmful. Their presence in the air is likely the result of buoyancy and wave action, which causes bubbles to burst and aerosols to form in the lake.
Southwestern Florida is prone to regular cyanobacterial blooms, which occur particularly frequently in Lake Okeechobee. Under favorable conditions, these organisms can form aerosols that are carried over significant distances. During blooms, residents of the region report coughing, difficulty breathing, or allergy-like symptoms; therefore, the study authors set out to develop a tool for routine monitoring of airborne toxins.
A Portable Air Sampling Laboratory
The project’s most significant achievement was the development of the ADAM (Airborne Detection for Algae Monitoring) device. It is a portable air sampler equipped with a filter and a special impinger—a system that captures water-soluble substances.
The design allows for 24-hour sampling at a height corresponding to the human breathing zone, i.e., 1.5–1.8 m above the ground. At an airflow rate of 2 liters per minute, 2,880 liters were analyzed over a 24-hour period. At the same time, water samples were collected from the same location to compare toxin concentrations in both environments.
Few algal blooms, but toxins are still present
During the study, 21 water samples were analyzed. As many as 13 of them—62 percent—showed no presence of cyanobacteria or algae in the surface layer. Only one sample contained Microcystis, Dolichospermum, Microcoleus, and diatoms simultaneously, while diatoms were found exclusively in six samples. Despite the small amount of visible cyanobacterial biomass, toxins were detected in both the water and the air.
Immunological analyses showed that brevetoxin was detected in 5 percent of the samples from the air filters. Anatoxin-a was also found in 5 percent of the samples from the impinger. In the water, the situation was more complex—microcystins and cylindrospermopsins were present in 29 percent of the samples, anatoxin-a in 5 percent, saxitoxins in 43 percent, and brevetoxins in 38 percent. Most concentrations remained low. The exception was a sample with a Microcystis aeruginosa bloom, in which the concentration of microcystin-LR reached 15 µg/l.
BMAA Is the Most Commonly Detected Toxin in the Air
The most interesting results concerned the neurotoxic β-N-methylamino-L-alanine (BMAA) and two related compounds—AEG and DAB. LC-MS/MS analyses showed that these compounds were present in the air significantly more often than other cyanobacterial toxins.
AEG was detected in 33 percent of the samples, while BMAA was detected in 5 percent. After hydrolysis, the detection rate for all three compounds increased. Even higher values were obtained from the impinger—AEG was present in 33 percent of the samples, BMAA in 29 percent, and DAB in 52 percent; after hydrolysis, AEG and DAB were detected in 100 percent of the samples, and BMAA in 29 percent. Importantly, the concentrations of these compounds in the material from the impinger were generally higher than on the filters, indicating that some toxins may be present in the air in dissolved form, rather than solely bound to particulate matter.
No Clear Correlation Between Water and Air
One of the most important conclusions drawn by the study’s authors is the lack of a clear correlation between toxin concentrations in water and in the air. Even with a small number of algal blooms and barely visible cyanobacteria in the studied water bodies, toxins were detectable in aerosols.
These results are consistent with earlier studies, which showed that aerosols can transport toxins over distances exceeding 30 km. The authors also point out that a person inhales about 500 liters of air per hour, so even people who are far from bodies of water may be chronically exposed to small amounts of toxins.
New Possibilities for Monitoring Hazards
According to the authors, the new device could serve as the basis for systematic air quality monitoring in areas at risk of algal blooms. By using an impinger, it will be possible to conduct rapid field analyses and obtain data on changes in toxin concentrations in near real time.
Researchers emphasize that a better understanding of inhalation exposure is essential for properly assessing the impact of toxins on human health. It is equally important to develop standardized methods for sample collection and analysis that will allow for the comparison of results obtained by different research teams. The presence of cyanobacterial toxins in the air is not limited to periods of spectacular blooms and requires further, long-term monitoring.
Source:
Metcalf, J.S.; Aparicio, M.; Banack, S.A.; Pim, J.; Cassani, J.R.; Cox, P.A. Developing Tools to Assess Airborne Cyanobacterial Toxins in Southwest Florida, USA. Toxins 2026, 18, 309. https://doi.org/10.3390/toxins18070309
