Key Laboratory of Integrated Regulation and Resource Development on Shallow Lake of Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China; College of Environment, Hohai University, Nanjing, 210098, China.
Key Laboratory of Integrated Regulation and Resource Development on Shallow Lake of Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China; College of Environment, Hohai University, Nanjing, 210098, China.
Chemosphere. 2022 Nov;307(Pt 4):136112. doi: 10.1016/j.chemosphere.2022.136112. Epub 2022 Aug 23.
Land transportation in the Yangtze River basin is an important source of microplastics in the East China Sea, so it is significant to clarify the source, fate and river-sea transition of microplastics. Taking the Yangtze River as the study area, the interpolation method was used to analyze the monthly changes of the microplastic load in the estuary, the input-output model was used to estimate the flux of microplastics into the sea, and the inflow process of microplastics was studied through correlation analysis. The results showed that: (1) The load of microplastics in the Yangtze River estuary varied with season, reaching the maximum in October, with a monthly load of 3.91 Gg; (2) The total amount of microplastics entering the sea in the Yangtze River basin was higher than the medium level, which was 7.02 Gg. Among them, tributary input was the most important source, accounting for 62.9%. Non-point and point sources were further subdivided into 11 categories, with the largest proportion of microplastics generated during vehicle trip. Spatially speaking, the microplastics transported in the midstream accounted for the largest proportion, accounting for 55.56%; (3) microplastics had a strong correlation with COD and TP, indicating that the inflow process of microplastics was similar to that of traditional pollutants, which were river retention, wastewater treatment plant removal, water consumption removal and inflow to the East China Sea. Although the proportion of the last one was only 8.05%, the ecological risk was still not negligible due to the huge amount.
长江流域陆运是东海微塑料的重要来源，因此阐明微塑料的来源、归宿和陆海传输过程具有重要意义。以长江为研究区，采用插值法分析了河口微塑料负荷的月际变化，运用输入-输出模型估算了微塑料向海通量，并通过相关分析研究了微塑料的入海过程。结果表明：（1）长江口微塑料负荷随季节变化，10 月最大，月负荷为 3.91Gg；（2）长江流域入海的微塑料总量处于较高水平，为 7.02Gg。其中，支流输入是最重要的来源，占 62.9%。非点源和点源进一步细分为 11 类，其中车辆行驶过程中产生的微塑料比例最大。从空间上看，中游输送的微塑料比例最大，占 55.56%；（3）微塑料与 COD 和 TP 具有很强的相关性，表明微塑料的输入过程与传统污染物相似，即河流截留、污水处理厂去除、耗水去除和流入东海。尽管最后一项的比例仅为 8.05%，但由于数量巨大，其生态风险仍不容忽视。
