Avaliação da toxidade crônica do fungicida Tebuconazole utilizando o organismo teste Daphnia magna

Abstract

The increasing agrochemicals use in agricultural activities and the excessive use of these substances can cause more damage to the human health and to the environment, creating the need to study and understand their behavior and their interactions with the ecosystem in which they are dispersed In this way the present study aims to evaluate the effects of chronic toxicity of the fungicide Tebuconazole through the parameters survival, reproduction, growth and morphology of the microcrustacean Daphnia magna. The chronic toxicity tests were performed according to NBR 13.373 (ABNT, 2017), where the organisms were exposed for 21 days at different concentrations of the fungicide Tebuconazole (100 μg / L - 500 μg / L and 20 μg / L - 80 μg / L). The first generation of the organisms produced in the chronic test was also evaluated in order to identify the possible effects of toxicity among multigenerations. In order to identify the interactions of the fungicide Tebuconazole with D. magna, a test to evaluate the recovery of the reproduction of exposed organisms was carried out. In this test the exposed organisms were arranged in M4 medium for the period of 10 days after finish the chronic test. Through the chronic toxicity tests carried out in this research, effects on the morphology, reproduction and mainly on the longevity of the exposed organisms could be observed. In addition to these effects, it was observed that the first generation of neonates from exposed parental organisms acquired greater resistance to the fungicide Tebuconazole, with Observed Effect Concentration (CEO) for longevity equal to 20μg/L for parental organisms, and equal to 80 μg/L for the 1st generation organisms. It was also observed that even after 10 days of permanence in culture medium (M4), no positive changes were observed regarding the reproduction parameter, thus indicating the permanence of the effects caused by the fungicide Tebuconazole. It was concluded that the Tebuconazole fungicide has the capacity to cause adverse effects of toxicity on the microcrustacean D. magna, emphasizing the importance of studying the effects of chemical substances in the long term.