Can cyanotoxins penetrate human skin during water recreation to cause negative health effects?

Cyanobacteria blooms and associated cyanotoxins pose significant public health risks during water recreation. Oral ingestion is the only recognized route of toxin exposure in water recreation guidelines. This review examines human skin as a barrier for the prevention of cyanotoxin absorption and investigates the likelihood of negative health effects through dermal exposure. Epidemiological studies of health effects from recreational exposure to algal blooms and toxins are summarized to highlight the importance of better understanding the toxicological effect of dermal exposure. The ability of a specific cyanotoxin to penetrate human skin is inferred by its physiochemical properties according to transdermal drug studies. The review identifies a disparity between the human health effects described in algal bloom exposure case studies and the toxicological skin exposure data. Skin penetration by algal toxins is likely and deserves further investigation.