The Tarumã, São Raimundo and Educandos basins, and their tributaries, are impacted by antropic influence. This study tried to evaluate the water toxicity of the hydrographic basins, through acute toxicity bioassay using Daphnia similis as test-organism and physical and chemical analysis. The results showed that, of the three basins, the water from Tarumã caused the most deleterious effect on D. similis.
ecotoxicology; acute toxicity; Daphnia similis
