Toxicity of a cyanobacteria bloom in Barra Bonita Reservoir (Middle Tietê River, São Paulo, Brazil)

• Published in: Ecotoxicology and environmental safety 2006-06, Vol.64 (2), p.163-170
• Main Authors: Sotero-Santos, Rosana Barbosa, Silva, Carlos Roberto De Souza E., Verani, Nelsy Fenerich, Nonaka, Keico Okino, Rocha, Odete
• Format: Article
• Language: English
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Animals; Applied ecology; Biological and medical sciences; Bloom; Brazil; Ceriodaphnia; Ceriodaphnia silvestrii; Cladocera; Cladocera - drug effects; Cyanobacteria; Cyanobacteria - chemistry; Cyanobacteria - physiology; Cyanobacterial toxins; Daphnia - drug effects; Daphnia similis; Ecotoxicology, biological effects of pollution; Eutrophication; Freeze Drying; Fresh water ecosystems; Freshwater; Fundamental and applied biological sciences. Psychology; General aspects; Lethal Dose 50; Male; Mice; Microcystins - analysis; Microcystins - toxicity; Microcystis aeruginosa; Rivers - microbiology; Synecology; Toxicity tests; Toxicity Tests, Acute
• ISSN: 0147-6513; 1090-2414
• DOI: 10.1016/j.ecoenv.2005.03.011

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 μg g −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.