Abstract: Microplastics(MPs)are prevalent in fresh water all over the world. Previous studies have shown that MPs pollution in the freshwater environment of China is particularly severe. Once ingested by aquatic organisms, MPs can be transmitted through the food chain and accumulated in high trophic organisms, which indirectly endangers the quality and safety of aquatic products, and eventually may become a potential threat to human health. However, most of the researches on MPs have been focused on marine ecosystems, and less been conducted for freshwater ecosystems, while freshwater ecosystems are more closely linked to and affected by human activities. In order to investigate the extent of MPs contamination in farmed river crabs (Eriocheir sinensis), the muscle and hepatopancreas tissues of Eriocheir sinensis, bottom water and bottom sediment from five aquafarms in Jianli city and Honghu city, Hubei Province were examined by chemical digestion combined with Raman spectroscopy. The results show that MPs were not detected in the muscle tissue and bottom sediment, but were detected in the hepatopancreas tissue of three aquafarms (mean abundance 1.22 g^-1), and in the bottom water of one aquafarm (0.13 L^-1). The shape of all detected MPs was mainly fragmented (74.28%) and the rest were granular; the chemical composition was polystyrene (PS), polyethylene (PE), and fluorinated ethylene propylene copolymer (Teflon FEP). All the detected MPs were classified according to color as transparent, white, and red. The sizes of the detected MPs were all in the range of 100~350 μm. The appearance of the MPs detected in the hepatopancreas tissues of Eriocheir sinensis crabs was similar to that in the bottom water, but the sizes were different. The appearance characteristics and chemical composition of MPs are closely related to their sources, and physical and chemical characterization can help for the tracing of MPs. The results of this study suggest that bottom water pollution may be a possible source of MPs in Eriocheir sinensis. The current risk of environmental MPs contamination during river crab farming in Hubei is low, and the risk of MPs contamination in Eriocheir sinensis is controllable.

Key words: Eriocheir sinensis, MPs, hepatopancreas, muscles, bottom water, sediment