Cyanobacterial (Blue‐Green Algal) Toxins and their Significance in UK and European Waters

Abstract The cyanobacteria (blue‐green algae) which commonly produce mass developments in fresh and saline waters are capable of producing toxins. These compounds have been responsible for the deaths of animals, birds and fish in many countries, and have been linked with several forms of human illness through skin contact and ingestion. Evidence has accumulated over the past decade that cyanobacterial toxins occur commonly in European waters which contain cyanobacterial mass growths. This paper summarizes the recent published occurrence and types of cyanobacterial toxins found in European waters with reference to poisoning incidents. Cyanobacterial blooms were particularly abundant in the warm dry summer of 1989 in the UK. The deaths of sheep and dogs and the cases of human illness that were ascribed to cyanobacterial toxins were followed by a more intensive and wider investigation into the extent of cyanobacterial toxicity in UK waters than had hitherto been undertaken. Of the cyanobacterial blooms sampled from over 90 freshwaters, approximately two‐thirds were toxic (lethal) according to mouse bioassay. Short‐term and long‐term needs for the recognition, quantification and management of problems which can be caused by potentially toxigenic cyanobacteria in water‐bodies used for recreation, aquaculture and potable supply are briefly discussed.