Harmful toxins produced by blue-green algae blooms are becoming airborne, posing a potential health risk to people living miles away from contaminated water bodies, according to a new study. These airborne toxins are a neurotoxin known as 2,4-DAB, produced by cyanobacteria.
Researchers from Brain Chemistry Labs in Wyoming, in collaboration with the nonprofit Calusa Waterkeeper, utilized a specialized device called ADAM (Airborne Detection for Algae Monitoring) to collect air samples across multiple locations in Southwest Florida. The device, designed to sample air at breathing height, uses both a glass fiber filter and a liquid impinger to capture airborne toxins. Samples were collected between July and December 2021.
Every air sample collected contained 2,4-DAB. This is the same neurotoxin previously identified in the brains of dolphins exhibiting symptoms similar to Alzheimer's disease.
While scientists have historically focused on contaminated food and water as primary exposure routes for these toxins, the findings suggest that inhalation of contaminated air may be an equally significant pathway. Cyanobacteria thrive in nutrient-rich waters, often caused by agricultural runoff or inadequately treated sewage, leading to rapid multiplication and toxin release.
Airborne Toxins Detected Without Visible Blooms
The study, published in the journal Toxins, found that detectable levels of toxins were present in the air even when there were no visible algae blooms on the water's surface. Water samples collected during the study showed no signs of cyanobacteria or algae at the surface in 62 percent of cases.
Despite the lack of visible blooms, air samples regularly contained toxins. Researchers concluded that this indicates a potential for chronic, low-level exposure through inhalation. "Even though we can avoid contaminated food and water, preventing exposure through breathing is far more difficult," said lead scientist Dr. James Metcalf. "These data suggest that you don't need to be close to toxic blooms to be exposed through breathing."
The air samples also tested for brevetoxins, a respiratory irritant associated with red tide blooms, but these were found in only five percent of samples. However, other cyanobacterial toxins were far more prevalent, with detection rates reaching 100 percent after sensitive testing.
Health Concerns Linked to Airborne Toxins
Harmful algae toxins have been linked to a range of health issues. In the short term, exposure can cause respiratory and gastrointestinal problems. Long-term concerns include potential links to neurodegenerative diseases such as Alzheimer's disease, amyotrophic lateral sclerosis (ALS), and Parkinson's disease, particularly associated with the neurotoxin BMAA.
Microcystins are also being investigated for their potential to contribute to neuroinflammation and cellular damage in the brain, potentially impacting conditions like Alzheimer's and Parkinson's. However, further research is needed to confirm these links in humans.
Brevetoxins, commonly found in red tide aerosols, are known respiratory irritants that can cause coughing, sneezing, wheezing, and chest tightness. Individuals with pre-existing conditions like asthma are particularly vulnerable, as inhaling these toxins can measurably decrease lung function.
Recent studies also indicate that inhaling microcystins, which have been found in lake and sea spray aerosols, can lead to harmful airway inflammation similar to a specific type of asthma and may exacerbate existing inflammatory lung conditions.