Lethal Effect and In Vivo Genotoxicity of Profenofos to Chinese Native Amphibian (Rana spinosa) Tadpoles

Amphibian populations are decreasing in size due to environmental stressors in most areas of southern China. Pesticides are known to be a group of potential stressors to amphibians, especially in agricultural ecosystems. Profenofos, an organophosphate insecticide and acaricide, is widely used for controlling insect pests in China. The aim of this study is to evaluate the acute lethality and genotoxicity of profenofos to amphibian under controlled conditions. Results showed that profenofos was highly lethal to tadpoles of Rana spinosa, with 50% lethal concentration (LC₅₀) values of 1.59, 1.14, 0.77, and 0.58 mg l⁻¹ at 24, 48, 72, and 96 h, respectively. DNA damage of erythrocytes was observed by alkaline single-cell gel electrophoresis assay at all tested sublethal concentrations. The study also showed, by micronucleus test, that profenofos at moderate to high sublethal concentration might have genotoxicity to the tadpole after 96 h exposure. Furthermore, based on our results, it is suggested that the alkaline single-cell gel electrophoresis assay could be used as a screening tool for biomonitoring of pesticide contamination in aquatic systems or agricultural ecosystems.