Toxicity of a cyanobacteria bloom in Barra Bonita Reservoir (Middle Tietê River, São Paulo, Brazil).
Ecotoxicol Environ Saf
; 64(2): 163-70, 2006 Jun.
Article
em En
| MEDLINE
| ID: mdl-15993489
ABSTRACT
In eutrophic waters during cyanobacterial bloom lysis, a blend of cyanobacterial toxins and other compounds are released into the water, affecting aquatic communities. This research investigated the effect of a simulated cyanobacterial lysis event. For this purpose, intact cells from a natural cyanobacterial bloom from Barra Bonita Reservoir (Tietê River basin, Brazil) were taken, and the cells were broken by repeated freeze/thaw cycles. The toxicity of the crude cyanobacterial extract was investigated using cladocerans (Daphnia similis and Ceriodaphnia silvestrii), and the hepatotoxicity of the cyanobacterial lyophilized material was confirmed by mouse bioassay. The results obtained using D. similis and C. silvestrii acute bioassays indicated 24-h LC(50) values of 186.61 and 155.11 mg L(-1), respectively. The 24-h LD(50) determined by intraperitoneal injection into mice was 445.45 mg dry kg(-1). Microcystin content was 311 microgg(-1) dry wt freeze-dried cyanobacteria. The acute tests with cladocerans were effective in indicating the toxicity of the crude cyanobacterial extract and in prognostiating the toxic effects of cyanobacterial blooms, at least on some usual components of the aquatic community, such as microcrustaceans.
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Base de dados:
MEDLINE
Assunto principal:
Cianobactérias
/
Daphnia
/
Cladocera
/
Rios
/
Eutrofização
/
Microcistinas
Limite:
Animals
País como assunto:
America do sul
/
Brasil
Idioma:
En
Ano de publicação:
2006
Tipo de documento:
Article