Cyanobacterial Toxins in Water

Abstract

Cyanobacteria (blue-green algae) commonly occur in fresh- and brackish waters and may produce massive annual growths as a consequence of nutrient enrichment from natural waters, agricultural fertilizer run-off, or from domestic/industrial effluents. The cyanobacterial species which dominate these growths typically belong to the genera which produce toxins. Cyanobacterial toxins cause fatal poisonings of agricultural livestock, wild animals, birds and fish on a world-wide basis. The involvement of the toxins in human health problems has also been inferred in several countries and their presence in drinking water sources is of interest to the drinking water industry. The occurrence and properties of cyanobacterial toxins are discussed here. New methods are being developed for the purification of the toxins and for their recovery and quantification from waters. These include the use of chemical, cytotoxicity and immunological methods to complement the mouse bioassay which has hitherto been used in cyanobacterial toxin studies with laboratory cultures and water samples. Information on the regulation of cyanobacterial toxin production and on the possible biological significance of the toxins in aquatic environments is also presented. A greater awareness of cyanobacterial toxins in waters destined for human use is required.

Mathematical modeling of Microcystis aeruginosa growth and [D-Leu1] microcystin-LR production in culture media at different temperatures

“…Laboratory studies have shown that the toxicity (LD 50 , mg dry algae kg À1 mice) of temperate strains of M. aeruginosa were highest at 18-20 C, and decreased greatly as the temperature increased above 28 C (van der Westhuizen and Eloff, 1985;Watanabe and Oishi, 1985). Culture-based studies have shown that MC concentrations are generally highest between 20 and 25 C (van der Westhuizen and Eloff, 1985;van der Westhuizen et al, 1986;Codd and Poon, 1988;Amé and Wunderlin, 2005).…”

L’Etat des Ressources En Eau au Maghreb En 2009

“…Toutefois, ces techniques classiques ne permettent pas une élimination totale des microorganismes pathogènes ; d'où la nécessité de soumettre l'eau à une autre technique de désinfection. En outre, parmi les inconvénients de ces techniques, il faut noter la production de boues, comme dans le cas de procédés de coagulation-floculation, ou de produits indésirables, comme dans le cas de certains procédés de désinfection, telle que la chloration (Godd et al, 1989).…”

Characterization of the Biocidal Spectrum of Extracellular Filtrates of Microcystis aeruginosa

“…Under favorable nutritional and environmental conditions, they proliferate into cyanobacterial blooms, which are becoming more common with the increasing eutrophication of fresh water bodies. The concern over the outcome of cyanobacterial blooms has increased during the past decades with increasing information on the detrimental power of the toxins produced by these organisms [1][2][3]. They are known to be a rich source of secondary metabolites.…”