Microplastic contamination and ecological risk assessment in two tree frog species (Hyla orientalis and Hyla savignyi) across Türkiye

This study was conducted to investigate the presence of microplastics (MPs) in individuals of Hyla orientalis and Hyla savignyi, two tree frog species naturally distributed in Türkiye, to determine the qualitative and quantitative distribution of these particles in their gastrointestinal tracts (GITs) and to analyze their morphological (color, shape, size) and chemical (polymer type) properties in detail. A total of 276 individuals were examined within the scope of the research, 76 of which belonged to H. orientalis and 200 to H. savignyi. A total of 192 microplastic particles were detected in their GITs, and the average size of these particles was determined to be 206.56 ± 12.88 µm. The most common microplastic type was PET (67.20%), its shape was fiber (76.00%), and its color was navy blue (25.50%). The highest proportion of microplastic-containing individuals was observed in H. savignyi (56.50%), and microplastic was found in only 11.84% of H. orientalis individuals. No statistically significant difference was found between the two species in terms of polymer type, microplastic shape, and color (p > 0.05). Data obtained from 24 different provinces across Türkiye indicate that microplastic contamination has a wide geographical distribution. The highest microplastic amount was recorded from Hatay-Hassa (44 pieces), followed by Kilis and Bitlis provinces. Significant differences were found between provinces in terms of color, shape, and polymer type (p < 0.001). These findings suggest that microplastic pollution is widespread in terrestrial vertebrates and may vary among species and geographic regions, suggesting that amphibians may be important bioindicators for monitoring ecosystem health.