Avaliação do potencial genotóxico da exposição aguda de três tipos de agrotóxicos em girinos de physalaemus gracilis (anura: leptodactylidae)

Abstract

Pesticides are chemical products widely used to control pests in agricultural production. Their use can contaminate aquatic environments, reaching non-target organisms, which when contaminated can suffer mortality, physiological changes and behavioral alterations. In this study, the acute toxicity and genotoxic effects were evaluated for three classes of pesticides: picloram herbicide; imidacloprid insecticide; chlorothalonil fungicide, in Physalaemus gracilis tadpoles. The acute test lasted 96 hours and tadpoles at embryonic stage 25 were used. Picloram had a LC50 of 15.81 mg.L-1, imidacloprid a LC50 of 69.20 mg.L-1 and chlorothalonil a LC50 of 0.036 mg.L-1. Picloram and imidacloprid showed low acute toxicity to P. gracilis, while chlorothalonil showed high acute toxicity and acute ecological risk to the species. The three formulations tested induced an increase in the frequency of micronuclei in blood cells of the analyzed tadpoles. Besides micronuclei other nuclear abnormalities were also observed in the cells such as: apoptosis, binucleated, blister, karyolysis, notched and lobed, showing that these compounds have genotoxic potential for this species. This study revealed amphibians to be good bioindicators of environmental quality, showing toxic and genotoxic effects when exposed to the analyzed pesticides.