Abstract

The eutrophication process involves important changes in the normal characteristics of water quality that may alter the balance between organisms. Microalgae particularly are very sensitive to changes. International standarized protocols were developed in order to detect water contaminants by their effects on microalgae, but it is important to evaluate contaminants over native species in our ecosystems. Using potassium dicromate as reference toxic, three native species were tested and one used in international protocols. Results showed that Chlorella vulgaris was the most sensitive organism both in acute tests and in chronic tests, and it happened even at concentrations below the levels permitted by environmental legislation. The use of biological tests as a complementary methodology for physical and chemical analysis is relevant when dealing with problems involving water quality.

Key words: Ecotoxicology, microalgae, water quality.