Problems on drinking water related to toxigenic Cyanobacteria: some cases studied in Argentina

Abstract

The massive presence of harmful Cyanobacteria in freshwaters has been acknowledged since 1878 when the death of a series of farm animals associated with a bloom of Nodularia spumigena was registered in Australia. In Argentina, these phenomena are known since 1944 when in the Bedetti shallow lake (Province of Santa Fe) about 1000 farm ducks died as a consequence of the ingestion of water after a mixed bloom of various species of blue green algae developed. The anthropic impact on aquatic ecosystems favours eutrophication and, combined with rising temperatures due to global climate change, promotes the development and expansion of harmful algal blooms. Cyanobacterial blooms are now widely recognised as a serious water quality problem with regard to both recreational and drinking water. In Argentina, several toxigenic Cyanobacteria have been reported and associated with blooms, being the most common genera Microcystis and Dolichospermum (Anabaena), while the most common cyanotoxins detected are microcystins. In this article we present four case studies related with the presence of toxigenic Cyanobacteria in drinking water, involving Snowella lacustris, Microcystis aeruginosa and species of Dolichospermum (Anabaena).