Microplastics in the sediment of Lake Ulansuhai of Yellow River Basin, China

As an emerging organic pollutant, microplastics in the ocean have been the subject of much study. However, there is a lack of research on freshwater environments, notably in sediment, China. Microplastics contamination in sediment of Lake Ulansuhai has been investigated in the study, and its concentration range was from 24 ± 7 to 14 ± 3 n/kg. Further, it exhibited a difference in spatial distribution with high content in the north zone of the lake far from the entrance of the drainage canal and it has a decreasing tendency with the flow from north to south in lake. Colored plastic particles acted as the dominated pollution type, and more than 79.69% of microplastics were smaller than 2 mm in size, existed as the form of fibers. FTIR results mirrored that the main types of microplastics were polyethylene, polyethylene terephthalate, polypropylene, and polyvinyl chloride. Results obtained from SEM/EDS showed that there were cracks, holes, and irregular curls on the surface of it, and these microplastics may provide attachment sites for other pollutants. The appearance of metallic elements such as Al, Ni, and Fe showed that microplastics and other pollutants in Lake Ulansuhai have a combined effect, which may aggravate the degree of pollution in the lake. PRACTITIONER POINTS: Microplastics were found in the sediment of Lake Ulansuhai with a spatial distribution characteristic. Abundance and morphological characteristics such as shape, color, and size have been analyzed in the paper. Polyethylene, polyethylene terephthalate, polypropylene, and polyvinyl chloride were the main types of microplastics in the sediment detected by FTIR. There were metallic elements combined on the surface of microplastics increased risk of combined pollution.