Li Wang, Brunetti Giuseppe, Zafiu Christian, Kunaschk Marco, Debreczeby Monika, Stumpp Christine
University of Natural Resources and Life Sciences, Vienna, Department of Water, Atmosphere and Environment, Institute of Soil Physics and Rural Water Management, Muthgasse 18, 1190 Vienna, Austria.
University of Natural Resources and Life Sciences, Vienna, Department of Water, Atmosphere and Environment, Institute of Soil Physics and Rural Water Management, Muthgasse 18, 1190 Vienna, Austria; University of Calabria, Department of Civil Engineering, Rende, Italy.
J Hazard Mater. 2024 Apr 15;468:133772. doi: 10.1016/j.jhazmat.2024.133772. Epub 2024 Feb 10.
Microplastics (MPs) present in terrestrial environments show potential leaching risk to deeper soil layers and aquifer systems, which threaten soil health and drinking water supply. However, little is known about the environmental fate of MPs in natural sediments. To examine the MPs transport mechanisms in natural sediments, column experiments were conducted using different natural sediments and MPs (10-150 µm) with conservative tracer. Particle breakthrough curves (BTCs) and retention profiles (RPs) were numerically interpreted in HYDRUS-1D using three different models to identify the most plausible deposition mechanism of MPs. Results show that the retention efficiency for a given particle size increased with decreasing grain size, and RPs exacerbated their hyper-exponential shape in finer sediments. Furthermore, the amounts of MPs present in the effluent increased to over 85 % as MPs size decreased to 10-20 µm in both gravel and coarse sand columns, while all larger MPs (125-150 µm) were retained in the coarse sand column. The modeling results suggested that the blocking mechanism becomes more important with increasing particle sizes. In particular, the attachment-detachment without blocking was the most suited parameterization to interpret the movement of small MPs, while a depth-dependent blocking approach was necessary to adequately describe the fate of larger particles.
存在于陆地环境中的微塑料（MPs）对深层土壤层和含水层系统显示出潜在的淋溶风险，这威胁到土壤健康和饮用水供应。然而，对于微塑料在天然沉积物中的环境归宿知之甚少。为了研究微塑料在天然沉积物中的迁移机制，使用不同的天然沉积物和微塑料（10 - 150微米）以及保守示踪剂进行了柱实验。利用三种不同模型在HYDRUS - 1D中对颗粒突破曲线（BTCs）和保留曲线（RPs）进行了数值解释，以确定微塑料最合理的沉积机制。结果表明，对于给定粒径，保留效率随粒径减小而增加，并且保留曲线在更细的沉积物中其超指数形状加剧。此外，在砾石柱和粗砂柱中，当微塑料粒径减小到10 - 20微米时，流出物中微塑料的含量增加到85%以上，而所有较大的微塑料（125 - 150微米）都保留在粗砂柱中。模拟结果表明，随着粒径增大，堵塞机制变得更加重要。特别是，无堵塞的附着 - 分离是解释小粒径微塑料运动最适合的参数化方法，而对于较大颗粒的归宿，需要采用深度依赖的堵塞方法来充分描述。
