Bioacumulação de agrotóxicos e genotoxicidade em anuros no sul do Brasil

Abstract

Agricultural expansion causes fragmentation, loss and pollution of ecosystems and it is one of the main factors linked to the decline in amphibian populations that have been occurring worldwide since the 1980s. Thus, our study aimed to evaluate native populations of anuran amphibians as contamination of their habitats in northern Rio Grande do Sul, southern Brazil. We evaluated the bioaccumulation of pesticides in populations of Leptodactylus latrans associated with agricultural areas and the genotoxicity of populations that inhabit different areas (agricultural and forest). We sampled 18 individuals of L. latrans in agricultural areas in the municipality of Passo Fundo and we removed the livers for the extraction of pesticides. We were tested 32 pesticides through chromatographic analysis using the LC-MS/MS system. We also applied the micronucleus test and nuclear abnormalities to assess genotoxic damage in 34 individuals, 19 from the agricultural area and 14 from the forest area. In the analysis we considered the following nuclear abnormalities: micronuclei, binucleated, notched nuclei, bebbled nuclei and lobed nuclei. All individuals of L. latrans presented bioaccumulation of pesticides. We detected nine pesticides in the livers of anurans in agricultural areas, including four insecticides, three herbicides and one fungicide. Deltamethrin was the most frequent pesticide and Carbosulfan was found in the highest concentration. We registered micronucleus and other nuclear abnormalities in both areas, however, the frequency of ANs was significantly higher in the agricultural area when compared to the forest area. Our results show contamination by pesticides of anurans that inhabit agricultural areas. In addition, we found greater genotoxicity in anurans in agricultural areas, suggesting that populations that live in agroecosystems may be threatened. The intense use of pesticides in agricultural crops is a threat to anurans and can aggravate population decline and species extinction. Assessing the health of anuran populations using agricultural areas is extremely important to develop group conservation plans.