Occurrence characteristics and influencing factors of microplastics in urban water bodies of Nanjing

Taking the urban rivers of Nanjing, Qinhuai River and Jiajiang River, as the research objects, an investigation and sampling were conducted from January 2022 to December 2023 to analyze the microplastic distribution characteristics of the two rivers during this period, to identify the possible sources of microplastics, and to assess the microplastic pollution in the study area using the pollution load index method. The results showed that the average abundance of microplastic particles in Qinhuai River was (612.3 ± 183.1) per cubic meter, with an abundance range of 333.3 to 942.1 per cubic meter, and the average abundance of microplastic particles in Jiajiang River was (556.2 ± 263.7) per cubic meter, with an abundance range of 201.1 to 933.3 per cubic meter; microplastic particle size in both rivers were mainly distributed in the range of 0 to 1000 μm, and the main shapes and colors of microplastics were fibrous (52.0% in Qinhuai River, 70.0% in Jiajiang River) and black (63.2% in Qinhuai River, 72.5% in Jiajiang River); the assessment of microplastic pollution in both rivers showed that the pollution degree was mild.