[Microplastic Pollution Characteristics and Ecological Environmental Risk Assessment in Water and Sediments of the Yiluo River Basin].

To explore the pollution characteristics and ecological environmental risk of microplastics in water and sediment of the Yilo River Basin， water and sediment samples were collected from 15 monitoring sections， the types， abundance， and particle size of microplastics in the water and sediment were identified using an Agilent 8700 laser infrared imaging system （LDIR）， and the ecological and environmental risk of microplastics in water and sediment of the Yiluo River Basin were assessed by the pollution load index （PLI） and polymer risk index （H）. The results showed that the types of microplastics are consistent in the water and sediment of the Yiluo River Basin， but the proportion of microplastics differs. For example， fluororubber （FPM）， chlorinated polyethylene （CPE）， polyurethane （PU）， and acrylate copolymer （ACR） microplastics accounted for 35.22% and 23.58%， 12.12% and 5.19%， 7.11% and 13.52%， and 5.33% and 22.07% of the microplastics in the water and sediment， respectively. The particle size of microplastics in the water and sediment is mainly concentrated in the range of 0-100 μm， accounting for 89.01% and 83.88% of the distribution， respectively. The average abundance of microplastics in the water and sediment was （412.48±39.91） n·L^-1 and （11 646.58±3 129.37） n·kg^-1， respectively， and there was a significant difference in the abundance of microplastics among different sections. The maximum abundance of microplastics of 728.86 n·L^-1 and 52 864.44 n·kg^-1 occurred in water and sediment of sections S12 and S3， respectively. The maximum average abundance of FPM microplastics was （145.25±40.52） n·L^-1 in water， and the maximum average abundance of ACR microplastics was （2 877.92±2 255.12） n·kg^-1 in sediment. The pollution load index method and polymer risk index method showed consistency in the ecological environment risk assessment results of microplastics， and microplastics in the water and sediment of the Yiluo River Basin generally present high risk or above.