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Blue-Green Algae (Cyanobacteria) in Inland Waters: Assessment and Control of Risks to Public Health
Blue-green algal toxins Annex B
Neurotoxins are produced by several species of blue-green algae, including species of Anabaena, Aphanizomenon and Oscillatoria. Several Anabaena neurotoxins exist, the most common of which cause depolarisation block at neuromuscular junctions. Aphanizomenon toxins have been identified as alkaloids of the same group as those responsible for paralytic shellfish poisoning. Signs of poisoning in animals that have ingested blue-green algal neurotoxins have included paralysis, cyanosis, respiratory arrest, muscular tremor, salivation, staggering and convulsions.
Hepatotoxins produced by several blue-green algae, including species of Anabaena, Microcystis, Oscillatoria, Nostoc, Coelosphaerium and Gomphosphaeria, have been identified as cyclic peptides. The hepatotoxins (microcystins) include over 75 variants; typically, several are present in a hepatotoxic bloom. Signs of poisoning in animals have included weakness, vomiting, cold extremities, piloerection, diarrhoea, heavy breathing and death due to circulatory failure within 2 to 24 hours. The toxins can also cause atypical pneumonia and are potent tumour promoters in laboratory animals. Many blue-green algae have lipopolysaccarides (LPSs) as normal components for their outer layers. The chemical composition of LPSs varies even between strains of one blue-green algal species. LPS may have contributed to skin irritation observed in swimmers in contact with blue-green algal blooms in the UK and to gastrointestinal disorders associated with blooms in several countries.
For sources of advice on toxicity see Annex C.
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