Bioaccumulation of Microplastics in Thrushes: Analysis for Monitoring Environmental Quality by Comparing Different and Innovative Extraction Techniques

Over recent decades, the exponential increase in plastic use has led to significant environmental and biodiversity damage when improperly disposed of. Natural factors such as solar UV radiation, wind, and currents break down plastic into micro plastics (MPs) and Nano-plastics (NPs), which have become major environmental pollutants. Smaller plastic fragments are more likely to be ingested by wild animals. Birds, crucial in the global trophic network and indicators of biodiversity, pollution, and environmental change, are the focus of this study. This research aims to develop two innovative, cost-effective methods for detecting micro plastics in wild birds’ stomachs while maintaining the micro plastics’ integrity and avoiding contamination. The study investigates the bioaccumulation of MPs in Turdus philomelos, the migratory wintering thrush in Italy, using samples from 100 specimens hunted in the Bari countryside and donated by the “Arci caccia” association. The environmental quality of their feeding areas is assessed by analysing MPs in the stomachs and the birds’ trophic regimes. The research seeks an alternative extraction method that avoids using chemical solvents such as potassium hydroxide (KOH), which can alter MP morphology, complicating physical characterisation. The results confirmed the presence of MPs, including filaments, fragments, and films of various colours, in all 100 thrush samples. These findings demonstrate that the two new flotation-based methods are effective tools for monitoring MP bioaccumulation and assessing environmental quality, given their simplicity and rapid analysis capabilities.