Cyanobacteria and cyanotoxins in the World: Review

Abstract

Water bodies of the world are gradually eutrophicated because of human interference in different ways like pesticide use, industrialization etc. The eutrophicated water is the good habitat for the luxuriant growth of algae and bloom forming cyanobacterial species. These blooms are harmful to animals and human being as they produce various toxic metabolites. Many studies have been done to elucidate the factors responsible for cyanobacterial bloom formation and their toxin production. As reported in these studies, factors favourable for cyanobacterial bloom formation are: light intensity, temperature, pH, nutrient in the form of phosphorus and water stability. But it is difficult to find out the factors responsible for cyanotoxin production. Some species of cyanobacteria have the ability to produce varieties of cyanotoxins. The cyanotoxins are neurotoxin, hepatotoxin, dermatotoxin, endotoxin and others. The effects of these toxins depend on the routes of exposure. So the drinking-water operators must beware about the growth pattern and species of cyanobacteria that dominate the bloom, the properties of the cyanotoxins (i.e., intracellular or extracellular), and the most effective treatment processes of these toxins.