MICROPLASTIC POLLUTION IN FISH FROM ARTIFICIAL BACKBONE RIVERS OF THE HUANGPU RIVER IN SHANGHAI

In order to investigate microplastic pollution in fish of five artificial backbone rivers of Huangpu River in Shanghai, the digestive tracts and gills of Coilia nasus, Hemiculter leucisculus, Carassius auratus, Pseudobrama simoni and Pelteobagrus nitidus were investigated. In addition, the distribution of microplastics in digestive tract walls and digestive tract contents of digestive tracts in 50 samples were further assessed at the same time. The results showed that 537 microplastics were detected in 200 fish samples of 5 species. The average detection rate was 83.00% and the average abundance was (2.69±2.74) items/ind. The distribution of microplastics in fish differed significantly in the five rivers. The detection rate of microplastics in digestive tract (70.50%) was significantly than that in gill (49.00%; P<0.01), and the abundance of microplastics in digestive tract (1.84±2.31) items/ind. was significantly higher than that in gill (0.85±1.20) items/ind. (P<0.05). Furthermore, 78 and 40 microplastics were detected in digestive tract walls and contents of 50 samples, respectively. The detection rate was 70.0% and the abundance was (1.56±1.63) items/ind. in digestive tract walls, which had significantly higher than that of digestive tract contents 42.0% and (0.80±1.14) items/ind. (P<0.05). Among the detected microplastics, fiber (53.07%) and fragment (33.15%), black (41.90%) and red (25.33%), and the size ≤1 mm (83.80%) accounted for a higher proportion. Gill microplastic had a higher proportion (59.76%) of fiber, while the digestive tract had a higher proportion (43.48%) of black, and the adhesion on digestive tract wall was mainly fragment (43.59%) and black (43.59%). Twelve chemical components were detected, with Cellophane (CP, 40.96%), polyethylene terephthalate (PET, 20.48%) and ethylene-vinyl acetate copolymer (EVA,12.05%) being the main polymer types. The research showed that the detection rate and abundance of microplastics in Huangpu River artificial backbone rivers in Shanghai were slightly higher than those in its natural waters. The types of dominant microplastics were significantly different, and the waste of household articles and agricultural film may be the important source of microplastic pollution.