User Tools

Site Tools


blue-green algae (BGA) toxins in waterways


  • waterways often become impacted by large blooms of blue green algae (BGA) which are capable of producing toxins
  • water treatments such as chemical sterilisation, boiling, filtration and UV sterilisation will NOT decontaminate the water of the toxins and thus it cannot be readily made potable
  • examples of such species include:
    • Aphanizomenonaceae Family
    • Microcystis sp
    • Chrysosporum ovalisporum
  • certain BGA species can produce cyanotoxins which have additional effects
    • there are a number of different potential toxins including micrcocystin, nodularin, cylindrospermopsin and saxitoxin
  • live cyanobacteria are unable to invade, colonize, and grow in humans or animals
  • one toxin (microcystin LR) has been classified by the International Agency for Research on Cancer (IARC) as a possible carcinogen (classification 2B). The clinical significance in humans with chronic exposure is not clear

avoid exposure

  • during blooms, do NOT:
    • swim in the water
    • drink the water
    • inhale droplets (eg. by water skiiing)
    • eat fish, molluscs, etc which eat the toxins
      • shell fish such as mussels can concentrate toxins, including saxitoxin, a neurotoxin which if eaten may result in paralytic shell fish poisoning
    • have contact with surface scum along shores
  • children and animals are particularly at risk
  • skin and eye irritation
  • mild respiratory tract effects and hay fever-like symptoms
  • nausea, vomiting and diarrhoea from ingestions
  • moderate effects may include the addition of abdominal pain, hypotension, headache, malaise and myalgia
  • large ingestions may cause multi-organ failure and death
  • the various toxins have differing properties but as a group, cyanotoxins can cause a range of effects including hepatotoxicity, cytotoxicity (affecting liver, kidney, heart, lungs, and stomach) and neurotoxicity

Mx of toxin exposure

  • remove exposure
  • supportive care
  • Rx skin irritation as for contact dermatitis
  • Rx eye irritation as for usual eye irritation - permanent harm is unlikely
  • there are no effective antidotes and no specific lab. tests to diagnose toxicity
bgatoxins.txt · Last modified: 2019/06/15 16:08 (external edit)