Water quality assessment and amphibian sensitivity in a protected area of the Atlantic Forest Biome

The Atlantic Forest biome harbors exceptionally high biodiversity and endemism. Turvo State Park protects the largest remnant of Semideciduous Seasonal Forest in Rio Grande do Sul. Despite this biological richness, stressors such as pesticide contamination threaten species survival and development. Amphibians, due to their ecological and physiological traits, are particularly sensitive to environmental disturbances. In this study, we assessed the sensitivity of Leptodactylus luctator tadpoles in lentic environments located inside the park and within its buffer zone. Ten lentic habitats were evaluated (five in each area). Water samples from the 10 sites were analyzed for pesticide residues, and a spawn of L. luctator was collected from a lake inside the park. The spawn was reared in the laboratory until tadpoles reached Gosner stage 25, after which they were transferred to the study sites. After 14 days, tadpoles were measured, weighed, and examined for the presence of micronuclei (MN) and erythrocyte nuclear abnormalities (ENA). Water analyses revealed clomazone and chlorpyrifos inside the park, while atrazine, azoxystrobin, and imidacloprid were detected in the buffer zone. MN and ENAs—including binucleate, anucleate, notched, and lobed nuclei, nuclear buds, karyolysis, apoptosis, and micronuclei—were observed in tadpoles from both areas. These findings highlight the importance of biomonitoring in protected areas, particularly given the anthropogenic pressures exerted on their borders.