Distribution of microplastics in tadpoles, adults, and habitats of three water frogs of Pelophylax spp.

Abstract

Microplastics (MPs) are ubiquitous environmental contaminants, and amphibians are especially susceptible owing to their dual aquatic and terrestrial life cycle and permeable integument. This research examines the presence, composition, and potential origins of microplastics in tadpoles, adult frogs, and their environments in different regions of Türkiye, concentrating on three Anatolian water frog species: Pelophylax ridibundus, P. bedriagae, and P. caralitanus. Samples were obtained from 11 sites, encompassing water bodies, sediments, tadpoles, and the gastrointestinal tracts (GITs) of adult frogs. MPs were examined for polymer type, morphology, and dimensions via stereomicroscopy and Fourier transforms infrared spectroscopy. Results indicated that microplastics were absent in 64% of sediment and water samples; nevertheless, elevated quantities were identified in areas with considerable human activity, such as İstanbul. Tadpoles demonstrated negligible MP intake, with merely 2 MPs identified among 157 samples, resulting in an average of 0.01 MP per individual. Conversely, 44% of the 100 adult frogs exhibited microplastics in their gastrointestinal tracts, averaging 1.52 microplastics per individual. The MPs were primarily fibers (90.8%) and comprised polymers such as ethylene–vinyl acetate (EVA) (32.5%) and polycyclohexylenedimethylene terephthalate (PCT) (20.8%). The study emphasizes the potential dangers of microplastics to amphibian health and reinforces the necessity of addressing microplastic pollution in freshwater habitats through focused conservation initiatives.