Institute of Hydraulic Engineering and Water Resources Management, RWTH-Aachen University, Mies-van-der-Rohe-Straße 17, 52074 Aachen, Germany.
Federal Institute for Hydrology, Am Mainzer Tor 1, 56068 Koblenz, Germany.
Environ Sci Technol. 2023 Apr 11;57(14):5569-5579. doi: 10.1021/acs.est.2c06885. Epub 2023 Mar 28.
The transport behavior of microplastics (MPs) in the fluvial environment is scarcely researched. Besides settling velocities and critical shear stress for erosion, only a few investigations aim at MPs' vertical concentration profile and the underlying theory required. Therefore, this paper's experiments investigate vertical concentration profiles of approximately spherical MP particles ( = 1-3 mm) with densities close to water (0.91-1.13 g/cm) in flow channels, coupling them with fundamental theory for the first time. The experiments were conducted in a tiling flume (slope of 0-2.4%) at 67 and 80 mm water depth, with a turbulent flow, velocities ranging from 0.4 to 1.8 m/s, and turbulence kinetic energy from 0.002 to 0.08 m/s. The measured profiles confirm the assumption that the concentration profile shapes of settling plastics are similar to those of sediments and running reversed for buoyant plastics. Furthermore, the hypothesis of the Rouse formula's applicability for floating and sinking plastics could be confirmed for approximately uniform flows. Future studies tying in with this research should increase particle properties and hydraulic parameter variation.
微塑料（MPs）在河流环境中的输运行为研究甚少。除了沉降速度和侵蚀的临界剪切应力外，只有少数研究旨在研究 MPs 的垂直浓度分布以及所需的基础理论。因此，本文的实验首次研究了在水流通道中具有接近水密度（0.91-1.13g/cm）的近似球形 MP 颗粒（=1-3mm）的垂直浓度分布，并将其与基础理论相结合。实验在倾斜水槽（坡度为 0-2.4%）中进行，水深为 67 和 80mm，水流为湍流，流速范围为 0.4 至 1.8m/s，紊流动能为 0.002 至 0.08m/s。测量的分布曲线证实了这样的假设，即沉降塑料的浓度分布形状与沉积物相似，而对浮塑料则相反。此外，对于近似均匀的流动，Rouse 公式适用于漂浮和下沉塑料的假设可以得到证实。未来的研究应增加颗粒特性和水力参数的变化。
