Cianotoxinas e suas implicações na saúde humana

Abstract

Cyanobacteria are prokaryotic microorganisms without flagella, photoautotrophic, capable of inhabiting different water environments. The growing accumulation of nutrients in water bodies, especially nitrogen and phosphorus leads to eutrophication process, which has beenmainly produced by human activities, and the main sources of enrichment are the discharges of domestic and industrial sewage and pollution from urban centers and diffuse pollution originated from agricultural regions. The result of eutrophication associated with variousenvironmental conditions leads to occurrence of blooming. The abundant growth of cyanobacteria in the surface of the water, called bloom, cause negative social, economic and environmental factors, as well as negative effects for both esthetic and organoleptic orders because cyanobacteria can produce metabolites such as geosmin and methylisoborneol (MIB)that can cause odor and unpleasant taste in drinking water and release highly toxic metabolic called cyanotoxins. Human beings are exposed to cyanotoxins through the treated water. According to its pharmacological action, the two main classes of cyanotoxins include the Neurotoxins: anatoxin-a, anatoxin-a(s) and saxitoxins, and the Hepatotoxins: microcystins, cylindrospermopsin and nodularins. Some cyanobacterial toxins can also produce irritation on contact defined as lipopolysaccharide (LPS). Neurotoxins have fast action, ranging fromminutes to a few hours, acting on the transmission of nerve impulses and can cause death by respiratory paralysis. The hepatotoxins have slower action, and may cause death within a range of few hours to few days due to liver damage and carcinogenic effects.