Avaliação de toxicidade de efluentes industriais utilizando organismos de três níveis tróficos.

Abstract

The aim of the study was to evaluate the quality of industrial effluents by physicochemical characterization and ecotoxicological acute assays with Danio rerio, Daphnia similis and Vibrio fischeri. We compared the sensitivities of organisms to test various types of industrial effluent (food, paper, beverage, petrochemical and pharmaceutical industries), and these organisms belong to three different trophic levels. Furthermore, the Microtox method with luminescent bacteria has been implemented, according to NBR 15411 (ABNT, 2006). In most tests, the effluent presented physicochemical parameters within the limits allowed by law. Still, sometimes sensitivities were caused in the test-organisms. Were used ETEI treated effluents and could be assessed the sensitivity of each organism in each industrial effluent. For the Food Industry 1, collections were made of raw and primary effluent which proved toxicity for the three test-organisms. This collection was also realized for the pharmaceutical industry, in which the raw effluent was toxic to the three organisms and the primary effluent was toxic to Daphnia similis and Vibrio fischeri. For the effluent from the Food Industry 2, Pulp and Paper Industry 2 and Beverage Industry were collected raw effluents and evaluated the toxicity by Microtox assay, demonstrating acute toxicity with low values of EC(I)50 for all industries. Some physicochemical parameters of the industries were correlated with the toxicity of the final effluent to Daphnia similis, Danio rerio and Vibrio fischeri by Spearman Correlation. The nonparametric Mann-Whitney test was used to compare groups of physico-chemical parameters that showed the presence or absence of toxicity. In some of the treated effluent, Food Industry 1, Food Industry 2, Pulp and Paper Industry 2 and Petrochemical Industry 1 were observed biological responses of bacteria, the hormesis effect, which indicates that the sample does not have acute toxicity but is very likely presenting chronic toxicity.