Table1_Microplastic in Water and Sediments at the Confluence of the Elbe and Mulde Rivers in Germany.XLSX

Accumulation of microplastics in aquatic environments is an issue of emerging concern. Initially, research focused on marine systems. However, recent studies also investigate the abundance of microplastics in freshwater environments. Rivers connect terrestrial with marine ecosystems and contribute a considerable share of macro- and microplastics to the oceans. A previous study found a large amount of micro-spheres in Dessau downstream the river mouth of the Mulde. Therefore, the objective of this research was to examine whether the Mulde river with its highly industrialized catchment contributes to the microplastic pollution of the Elbe. Sediment (Van Veen grab sampler) and water samples (filter cascade with the smallest mesh size 50 μm and nets with the smallest mesh size 150 μm) were taken from the Elbe river up- and downstream the confluence with the Mulde. After extensive sample preparation, we examined the samples under a digital microscope and determined polymer types by pyrolysis Gas Chromatography/Mass Spectrometry (pyr-GC-MS). The amount of primary microplastics increased in sediment and water samples just downstream the confluence. Those microplastics originate probably from the Mulde. We measured larger amounts and different shapes of microplastics in filter cascades that have a smaller mesh size compared to the nets.

水生环境中微塑料的累积已成为日益受到关注的新兴环境问题。早期相关研究多聚焦于海洋生态系统，而近年来的研究也开始关注淡水环境中的微塑料丰度。河流是连接陆地与海洋生态系统的纽带，同时也是向海洋输入大量宏观塑料与微塑料的重要途径。此前一项研究在穆尔德河河口下游的德绍区域发现了大量微球塑料。因此，本研究旨在探究流域高度工业化的穆尔德河是否会加剧易北河的微塑料污染。本研究在易北河与穆尔德河汇流处的上下游区域采集了沉积物样品（采用范维恩采泥器（Van Veen grab sampler））与水样：其中水样分别采用孔径最小为50μm的过滤级联装置，以及孔径最小为150μm的网具进行采集。经严谨的样品前处理后，研究人员通过数码显微镜对样品进行观测，并采用热解气相色谱-质谱联用法（pyr-GC-MS）鉴定样品中的聚合物类型。仅在汇流处下游的沉积物与水样中，原生微塑料的含量出现上升，这类微塑料大概率源自穆尔德河。相较于网具，孔径更小的过滤级联装置所采集到的微塑料数量更多，且形态种类也更为丰富。