Microplastic (MP) pollution poses a significant threat to freshwater ecosystems, yet its impact on amphibians remains poorly understood. This study provides the first assessment of MP contamination in two amphibian species, Pelophylax sp. and Bufotes perrini, from the Hyrcanian forests of northeastern Iran. A total of 136 individuals were examined, revealing that 72 % of samples contained MPs. The dominant MP type was fibers (54 %), with colorless/white particles (58 %) and sizes < 0.5 mm (38 %) being the most prevalent. FTIR spectroscopy identified polyurethanes (43 %) and polystyrene (27 %) as the primary polymers. A significant, albeit weak, positive correlation was found between MP abundance and the residual index (R = 0.1977, p < 0.021), indicating that larger-bodied individuals ingested more MPs. Higher MP loads were observed in individuals from upstream sites, particularly near urban and touristic areas, suggesting human activities as major pollution sources. These findings highlight the urgent need for conservation strategies to mitigate MP contamination in amphibian habitats.
