An overview of problems caused by toxic blue-green algae (cyanobacteria) in drinking and recreational water.

Abstract

Toxic blue-green algae present a hazard to human populations that are exposed through drinking water or recreational activities. The toxins include hepatotoxic peptides, a cytotoxic alkaloid, neurotoxic alkaloids, and saxitoxin derivatives, with allergens and lipopolysaccharides also present. The recorded outbreaks of hepatoenteritis through drinking water have occurred in chlorinated supplies at the time of either natural or copper-induced lysis of blue-green algal water blooms. Recent deaths of dialysis patients were from liver injury caused by blue-green algal toxins contaminating a water supply carried by tanker from an algal infested reservoir source. Recreational exposures to water containing toxic blue-green algae have caused illnesses ranging from acute pneumonia and hepatoenteritis to mild skin irritation and gastroenteritis. Water safety guidelines for cyanobacterial toxins are under development by WHO, and a provisional guideline for microcystin-LR of 1 μg/L has been approved.