长江-涨渡湖水系沉积物微塑料分布与赋存特征

Distribution and Occurrence of Microplastics in Sediments of the Zhangdu Lake System in the Yangtze River Basin

探究微塑料在涨渡湖水系的分布和赋存特征,可为湖泊沉积物微塑料老化及生物毒性风险评估提供基础数据。在阻隔湖泊涨渡湖、七湖、陶家大湖、邻近长江干支流和连通水道设置11个采样点,通过采集表层沉积物,分析了长江-涨渡湖水系沉积物微塑料丰度、尺寸、形状和种类组成。结果显示,长江-涨渡湖水系所有采样点沉积物中均有微塑料存在,其干物质中微塑料平均丰度为2602.25 n/kg,其中涨渡湖的微塑料丰度最高,为5687.69 n/kg。微塑料尺寸主要分布在[20,50]μm,占微塑料总颗粒数的59.04%;尺寸大于100μm时,微塑料丰度随尺寸的增大而减小;薄膜状微塑料最多,占微塑料总颗粒数的56.06%;微塑料种类主要为聚氯乙烯、聚对苯二甲酸乙二醇酯、氟橡胶和氯化聚乙烯。研究结果有助于了解湖泊微塑料赋存现状及提升水生态环境质量。

In this study,we investigated the distribution and occurrence of microplastics in sediments of the Zhangdu Lake system,focusing on spatial distribution,size,shape and composition.The study aimed to provide basic data for evaluating the aging of microplastics in lake sediments and the risk of biological toxicity.In July 2022,a total of 11 sampling sites were established to collect surface sediments in the isolated lakes of Zhangdu Lake,Qihu Lake,Taojia Lake,the adjacent mainstream and tributaries of Yangtze River,and the connected waterways.The abundance,size,shape and species composition of microplastics in the sediments of the Zhangdu Lake water system were then analyzed.Simultaneously,the sources of microplastics and their potential ecological and toxicological risks were explored.Results show that:(1)microplastics were found in the sediments of all sampling sites,with an average abundance of 2602.25 particles/kg of dry matter.The highest microplastic abundance in Zhangdu Lake was 5687.69 particles/kg.The average microplastic abundance in the Zhangdu Lake water system was in the flowing order:isolated lakes(3990.64 particles/kg)>connected waterways(2532.22 particles/kg)>adjacent mainstream and tributaries(1814.67 particles/kg).(2)Microplastics were divided into four size ranges(20-50μm,50-100μm,100-150μm,150-350μm),and microplastics were primarily in the smallest size range that accounted for 59.04% of the total microplastic particles.For particles larger than 100μm,the abundance decreased with increasing size.(3)The shape of the microplastics were primarily film-like,granular and fibrous,accounting for 56.06%,37.30% and 6.64% of the total plastic particles,respectively.(4)A total of 26 types of microplastic were detected in the Zhangdu Lake water system,primarily consisting of polyvinylchloride(PVC),polyethylene terephthalate(PET),fluororubber(FPM),chlorinated polyethylene(CPE),polyurethane(PU)and acrylate copolymer(ACR)that accounted for 71.40% the total plastic particles.This research provides a reference for scientifically assessing the characteristics of microplastics in lakes and improving the quality of the water ecological environment.