CYANOBACTERIAL TOXINS - A PROBLEM FOR DRINKING WATER IN SOUTH BRAZILIAN RESERVOIRS

YUNES, J.S.(1)

(1)Unidade de Pesquisas em Cianobactérias, FURG, RS, Brazil

Cyanobacteria are prokaryotic photoautothrophic microorganisms remanescent from precambrian primitive filamentous forms. Some cyanobacterial genera are able to fix atmospheric N₂ and some genera develop massive growth (>1O⁶ cells.mL^-1) in water reservoirs, among those, some cyanobacteria are also able to produce potent toxins (neuro or hepatotoxins). In South Brazil the occurrence of toxic blooms have become frequent in reservoirs for drinking-water purposes. The majority of blooms includes cyanobacteria of the genera Microcystis, Anabaena and/or Cylindrospermopsis. Peptide toxins named microcystins are produced by Microcystis and Anabaena species and are common in the euthrophic waters of dams near urban centers.  Alternatively, in the same environments coiled Anabaena species produced anatoxin-a (S)-like neurotoxins.  Other neurotoxins, with paralytic effect, named saxitoxins, are produced in turbid waters of shallow lakes and dams by Cylindrospermopsis and Planktothrix species. In general all cyanobacterial blooms are causing serious concern to the Health Authorities and staff of  Water treatment Plant Units. Brazil has established a temporary regulation for three cyanotoxins in potable waters and their analysis in water are subject of a constant effort of the “Unidade de Pesquisas em Cianobacterias” of FURG, Southern-Brazil. Following the present cenario of problems with cyanotoxins in potable waters in Brazil,  a broader discussion on the matter is required in order to gather efforts and further capabilities to overcome this foreseen worst difficulties.

CORRESPONDENCE TO:

YUNES, J.S. Unidade de Pesquisas em Cianobactérias, FURG, RS, Brazil E.mail: dqmsarks@super.furg.br