Microplastic Contamination in Three Amphibian Species: Implications for Amphibian Ecosystems

Abstract

Background and Objectives: This study aims to investigate the presence and characteristics of microplastics in the tadpoles of three amphibian species: Hoplobatrachus chinensis, Hylarana erythraea, and Kaloula pulchra.

Methodology: Tadpole samples were collected from two study areas, Bueng Kan and Khon Kaen provinces. The tadpoles were euthanized with chlorotone solution and preserved in 70% alcohol. The species were identified by examining external morphological characteristics and comparing them with relevant descriptions. The tadpoles were digested using 30% hydrogen peroxide at 60°C, then allowed to settle at room temperature. The remaining residue was filtered using Whatman No. 1 filter paper (110 mm), and the filter paper was examined for microplastic particles using a Nikon SMZ-745T stereo microscope. Images and measurements of the microplastics were taken using the NIS Elements software.

Main Results: This study used 12 tadpole samples, consisting of 3 tadpoles of H. chinensis (average TL 17.5±1.03; stage 29), 3 Hy. erythraea (average TL 38.5±5.69; stage 43), and 6 K. pulchra (average TL 26.8±1.23; stage 38). The results revealed a total of 26 microplastic particles, comprising both fragments and fibers. The banded bullfrog had the highest number of microplastics (15 particles), all of which were fibers. Microplastics of varying sizes were found in all three species, with the rice frog showing a higher number of fragment-type microplastics.

Conclusion: This study reports the presence of microplastics in tadpoles of amphibians from Thailand and emphasizes the importance of further research in the future.