Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10880675 | Toxicon | 2005 | 9 Pages |
Abstract
Toxic cyanobacteria in public water supply reservoirs represent a serious health risk as they can release potent cyanotoxins into the water. In the present study we analyzed surface water collected from the Utinga Reservoir, the main source of drinking water for the city of Belém-PA, in order to characterize the reservoir's cyanobacterial biota and to determine the toxicity of these organisms and the concentration of microcystins in raw and treated water. The cyanobacterial biota included potentially toxic genera such as Aphanizomenon, Microcystis, Nostoc, Oscillatoria, Planktothrix and Radiocystis. Mouse bioassays revealed a 43.6% frequency of hepatotoxic strains, including 30.8% Microcystis viridis strains and 12.8% Radiocystis fernandoi strains, with the lowest LD100 (ip) of 45 and 75 mg kgâ1 body weight, respectively. Subacute hepatotoxicity was observed for Aphanizomenon cf. gracile and Coelomoron pusillum strains. HPLC analysis confirmed the production of microcystins at maximum concentrations of 4.22 μg mgâ1 dry weight for M. viridis and 2.47 μg mgâ1 for R. fernandoi. Microcystins at concentrations of up to 1.25 μg Lâ1 detected in raw water by ELISA, together with a cyanobacterial density of 20,000 cells mLâ1, represents the first report of a bloom of cyanobacteria for an Amazonian water body.
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Authors
José Maria dos S. Vieira, Maria Teresa de P. Azevedo, Sandra Maria Feliciano de Oliveira Azevedo, Ricardo Yukio Honda, Benedito Corrêa,