Co-Occurrence of Taste and Odor Compounds and Cyanotoxins in Cyanobacterial Blooms: Emerging Risks to Human Health?

• Published in: Microorganisms (Basel) 2023-03, Vol.11 (4), p.872
• Main Authors: Manganelli, Maura, Testai, Emanuela, Tazart, Zakaria, Scardala, Simona, Codd, Geoffrey A
• Format: Article
• Language: English
• Subjects: 2-Methylisoborneol; Animals; Aquaculture; Aroma compounds; Chemical properties; Composition; Cyanobacteria; Drinking water; Efficiency; Environmental studies; Food contamination & poisoning; Geosmin; Health aspects; Health risks; Inhalation; Ionone; Low concentrations; Marine toxins; Metabolites; microcystins; Odors; Physiological aspects; Recreation; Respiration; Review; Taste; Toxicity; Volatile compounds; Water treatment plants; β-cyclocitral; β-ionone
• ISSN: 2076-2607; 2076-2607
• DOI: 10.3390/microorganisms11040872

Cyanobacteria commonly form large blooms in waterbodies; they can produce cyanotoxins, with toxic effects on humans and animals, and volatile compounds, causing bad tastes and odors (T&O) at naturally occurring low concentrations. Notwithstanding the large amount of literature on either cyanotoxins or T&O, no review has focused on them at the same time. The present review critically evaluates the recent literature on cyanotoxins and T&O compounds (geosmin, 2-methylisoborneol, β-ionone and β-cyclocitral) to identify research gaps on harmful exposure of humans and animals to both metabolite classes. T&O and cyanotoxins production can be due to the same or common to different cyanobacterial species/strains, with the additional possibility of T&O production by non-cyanobacterial species. The few environmental studies on the co-occurrence of these two groups of metabolites are not sufficient to understand if and how they can co-vary, or influence each other, perhaps stimulating cyanotoxin production. Therefore, T&Os cannot reliably serve as early warning surrogates for cyanotoxins. The scarce data on T&O toxicity seem to indicate a low health risk (but the inhalation of β-cyclocitral deserves more study). However, no data are available on the effects of combined exposure to mixtures of cyanotoxins and T&O compounds and to combinations of T&O compounds; therefore, whether the co-occurrence of cyanotoxins and T&O compounds is a health issue remains an open question.