How do insecticides affect non-target animals? The oxidative, genotoxic and histopathological effects of carbofuran in Dendropsophus minutus tadpoles

Abstract

Carbofuran (CB) is a carbamate insecticide that is applied extensively in sugarcane and banana plantations but can also be often found in aquatic environments adjacent to farmland. In this context, the present study evaluated the ecotoxicological effects of carbofuran on Dendropsophus minutus tadpoles. The animals were exposed to different concentrations of CB (3 µg/L, 5 µg/L, 7 µg/L, and 9 µg/L) for 96 h, and a negative control (dechlorinated water). The tadpoles exposed to 9 µg/L of CB presented a decrease of 57.97% in the activity of the dismutase superoxide enzyme, and a 25.72% reduction in catalase, in comparison with the control, while the glutathione S-transferase enzyme increased 19.10%. The tadpoles exposed to the highest CB concentration also presented significant genotoxic damage, a fivefold increase in nuclear abnormalities, and a 63.63% increase in histopathological alterations of the liver, in comparison with the control. The 7 µg/L CB group presented a twofold increase in malondialdehyde levels in the cells and a high frequency of nuclear abnormalities (an increase of 661.41%) in comparison with the control. Given this, while the sale and use of carbofuran are now prohibited in Brazil, this insecticide persists in the environment, where it is harmful to non-target animals, affecting their cellular homeostasis and, in turn, their health.