Bioassays with Aquatic Organisms: Toxicity of Water and Sediment from Cubatão River Basin

Biological assays applied to river water samples and sediment aqueous extracts have been used to identify stretches of waterways that are toxic, providing an important complementary tool in water quality surveys. Assays with Daphniasimilis, a microcrustacean, were performed with river water samples and sediment extracts from 18 sampling stations in Cubatão region. Water samples from rivers that receive discharges from fertilizer industries were assayed with the algae Chlorellavulgaris. The results showed no acute toxicity in samples and extracts collected upstream from the industries. Downstream from the industries acute toxicity was detected in several samples, at some stations toxicity was at high levels demonstrating improper water conditions for supporting aquatic life.