Toxidade aguda e crônica de agrotóxicos em girinos de Physalaemus cuvieri (Anura, Leptodactylidae)

Abstract

Brazil is the largest consumer of pesticides in the world however the research of how these pesticides affect the wildlife is scarce. Among the vertebrates groups, amphibians are particularly important in research that verify the impact of pesticides, because the correlation between these products and the species decline. This study aimed to evaluate the acute and chronic toxicity of commercial formulations of pesticides: atrazine (herbicide), cypermethrin (insecticide) and tebuconazole (fungicide) in tadpoles Physalaemus cuvieri. Species spawns were collected in nature and carried out under controlled conditions in the laboratory. The toxicity tests were carried out under standard conditions to determine the lethal concentration (LC50) using 96 hours of exposure and also the effect of sub-lethal concentrations of pesticides for seven days. In addition, we made swimming activity tests on tadpoles exposed to sublethal concentrations. The lethal concentration (LC50) was 24.39 mg / L of atrazine, 1.4 mg / L for cypermethrin and 1.13 mg / L for tebuconazole. The test was performed with chronic concentrations 1/10, 1/50 and 1/100 LC50, being exposed to 2.4; 0.48 and 0.24 mg / L of atrazine; 0.14; 0.028; 0.014 mg / l Cypermethrin and 0.11; 0.02; 0.01 mg / L tebuconazole. In the acute test, atrazine showed lower toxicity while cypermethrin and tebuconazole demonstrated toxicity medium for P. cuvieri. Swimming activity of tadpoles was affected by applying sublethal doses of atrazine and cypermethrin, but not in exposure to tebuconazole. The cypermethrin was the insecticide that most altered the swimming activity of the individuals tested.