Avaliação da ecotoxicidade aguda e da genotoxicidade do clorpirifós antes e após o tratamento por processos avançados de oxidação

Abstract

Chlorpyrifos is one of the most used organophosphate insecticides in agriculture nowadays. This compound possess a broad spectrum of action.and it is registered for agricultural use in the control of various insects on crops of barley, wheat, oats and a wide variety of vegetables. However, it represents a serious risk to human health by acting as an inhibitor of the acetylcholinesterase enzyme, causing cholinergic syndrome and being, for that reason, neurotoxic. Therefore, treatments for degradation of this insecticide must be developed and improved. Among the treatments studied for the degradation of chlorpyrifos, the photodegradation system using UV/H2O2 has proven to be efficient. To evaluate the possible effects of this contaminant and evaluate if there is a post-treatment ecotoxicity on aquatic organisms, ecotoxicity tests may be used. In this work, we evaluated the acute ecotoxicity of chlorpyrifos for Daphnia magna and Aedes aegypti and genotoxicity for Danio rerio fish. The acute ecotoxicity tests to D. magna showed an EC50 of 0.16 ug L-1, while for the larvae of A. aegypti, EC50 was 0.83 ug L-1.The genotoxic effects could not be determined at the studied concentrations. The evaluation of the acute ecotoxicity of chlorpyrifos for samples treated by the UVC and UV/H2O2 processes for D. magna presented a FT>16, while for the A. aegypti larvae, treated samples by UVC showed low toxicity (4.0% of immobilized organisms), while the sample treated by UV/H2O2 showed higher toxicity (78.7% ofimmobilized organisms ).