Microplastics in wild fish in the Three Gorges Reservoir, China: A detailed investigation of their occurrence, characteristics, biomagnification and risk.

Microplastics (MPs) pollution in freshwater poses a risk to various ecosystems and health security. In 2018, the Chinese government banned fishing since 2018 in the Three Gorges Reservoir (TGR), but the fate and risk of MPs in wild fish remain unclear. Therefore, a detailed investigation was conducted into the occurrence of MPs in 18 wild fish species in the TGR using a Micro Fourier Transform Infrared Spectrometer, and the trophic transfer and risks were assessed. MPs in fish were aged, with abundances ranging from 0.68 ± 0.98 to 4.00 ± 2.12 items/individual. Most particles were less than 1 mm in size (73.4 %), with fibers being the dominant shape (48.9 %) and transparent as the dominant color (35 %). Polyethylene (PE) was the most prevalent type. The bioconcentration factor (BCF), bioaccumulation factor (BAF), trophic magnification factor (TMF) and polymer hazard index (PHI) were low, suggesting no trophic transfer and a low risk of MPs. The BAF may provide a more reasonable description of the degree of enrichment of MPs, and 'items/individual' or 'g/individual' can be used to describe MPs concentrations in fish. This study proposes new insights and prospectives that can help researchers better understand MPs enrichment in fish across various trophic levels.