微塑料断面分布的不均一性OA北大核心CSTPCD

Plastics are commonly utilized in daily life and manufacturing processes,owing to their remarkable properties.However,they are not easily degraded in the environment,leading to many microplastics that may pose potential ecological and environmental risks.Therefore,identifying the abundance and conducting risk assessment of microplastics in water bodies are crucial to reduce the safety concerns posed by microplastics.However,previous studies on the abundance of microplastics in the watershed mostly focused on the surface water of rivers,ignoring the influence of horizontal sampling points and sampling depth on the distribution of microplastics,and the conclusions obtained are not representative enough.The Ganjiang River is a major tributary in the middle reaches of the Yangtze River.In this study,samples were collected and analyzed at a representative section of the Ganzhou urban section,and changes in the abundance,color morphology,particle size,and polymer status of microplastics were analyzed horizontally and vertically.The risk levels of microplastics were calculated using the ecological risk index method.The results showed that the microplastic abundance of the representative section was 0.25-0.35 n·L-1,and the average microplastic abundances in the surface,middle,and bottom waters were 2.65,2.03,and 0.91 n·L-1,respectively.The horizontal microplastic abundance increased in the area near the riverbank,and the vertical microplastic abundance decreased with increasing sampling depth.The main shapes of microplastics were fiber and debris,mainly black,with a particle size range of 0.125-3.000 mm,accounting for more than 94%,and the aggregate types were polyethylene,polypropylene,polystyrene,polyamide,ethylene-vinyl acetate copolymer,polycarbonate,polyethylene terephthalate,and polyvinyl chloride.The potential risk level of microplastics in the study area was Class Ⅱ.In general,the horizontal and vertical distributions of river microplastics in the Ganzhou urban section of the Ganjiang River were uneven,and the degree of pollution was relatively low.This study will promote the understanding of the distribution characteristics of vertical microplastics in urban water bodies,and has guiding significance for the investigation of microplastics in other water basins.