Microplastic accumulation in four commercial fish from fish market: Implications for human dietary risk assessment

Abstract

Microplastics (MPs) exist widely in aquaculture waters, and are inevitably ingested by farmed aquatic animals, but the subsequent dietary risks of consuming aquaculture products are unclear. We seasonally sampled four commercially important fish species (Aristichthys nobilis, Siniperca chuatsi, Carassius auratus, and Trichiurus lepturus) from Shanghai fish market to analyze the MPs in these fish. An optimized digestion protocol (10 % KOH, 60°C, 24 h) yielded the 95.28 % MPs recovery rate. MPs in commercial fish were quantified and characterized through dissecting microscope and micro-Fourier transform infrared spectrometer (μ-FTIR), respectively (spectral match threshold >70 %; limit of detection: 50 μm). Human dietary exposure risks were assessed by correlating MP abundance with region-specific aquatic product consumption patterns. The results showed a total of 11 types of natural, semi-synthetic and synthetic polymers were detected, with a detection rate of 60.94 %. The most abundant polymer types were polyester (PES), rayon (RY), polyethylene terephthalate (PET), and cellulose (CE). MPs abundance in edible tissues was from 0.000 to 0.029 items/g. Gut accumulated the most MPs, followed by gills, viscera, belly, and head. People annual dietary intake (ADI) of MPs was roughly 241 items/year via fish, with the estimated dietary intake (EDI) reaching 3.45 items/year/kg for males and 4.81 items/year/kg for females. The polymer risk index (H_i) for the quartet of assessed fish species indicated a low to medium risk. Our study emphasizes the dietary risk posed by MPs in typical commercial fish. However, the risk management for MPs still needs to be enhanced in the future.