Supplementing its first opinion issued in 2021 on the ingestion of mussels contaminated with brevetoxins (BTX) in Corsica, the Agency studied the other routes of exposure to these marine toxins.
Inhalation of contaminated spray in the event of a bloom of these microalgae is the main route of exposure reported in other areas of the world, such as Florida. This can occur during swimming or during professional or leisure activities, near or on the beach. It can cause sneezing, runny nose and throat irritation. By settling on the face and skin, sea spray contaminated with BTX is also likely to cause skin and eye irritation. Professionals who work in contaminated areas (lifeguards, scientists, people collecting shellfish, etc.) are the most exposed, with pregnant women, people with asthma and those with chronic respiratory problems being the most sensitive.
Concerning direct contact with contaminated water, if skin irritations have been observed, no study has yet confirmed this route of exposure.
While BTXs have been monitored in shellfish since January 2018, they are currently not monitored in seawater. As BTXs are emerging toxins, new knowledge is needed, especially via environmental monitoring of bathing sites located near the monitoring points of the REPHY where species of potential BTX producers have been detected in the past. This knowledge will make it possible to anticipate the appearance of a “red tide” on the French coast, a sign of the abundant presence of BTX-producing microalgae, and to define the most appropriate management measures.