Chen Xin, Wan Yong, Jia Jia, Qiang Xue, Wu Chenxi
State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.
University of Chinese Academy of Sciences, Beijing, 100039, China.
Heliyon. 2023 Jul 19;9(8):e18464. doi: 10.1016/j.heliyon.2023.e18464. eCollection 2023 Aug.
Contamination of groundwater by microplastics (MPs) is increasingly reported and attracts a growing attention due to their potential risks. To understand how MPs migrate into groundwater, many previous works have investigated their transport using man-made microspheres of few microns or smaller as models. However, MPs observed in the environment are more diverse in size, shape, and type, which may have different migration behaviors. In this work, the transports of irregularly shaped polyethylene (PE) particles in the sand packed column were studied. Small MPs (22-37 μm) generally have high mobility than large MPs (44-74 μm) but can also be affected by aging. Aging decreased the hydrophobicity of the MPs and increased their surface negative charge, which can facilitate the transport of MPs. However, the physical barrier of space in the porous media might have a greater influence on their transport. The retention of the MPs was enhanced with the increase of pressure due to compression that decreased pore size. Results from this study showed that MPs of environmental features can also be transported in the groundwater but the processes could be governed by different factors, such as physical interception and steric hindrance.
微塑料（MPs）对地下水的污染报道日益增多，因其潜在风险而受到越来越多的关注。为了解微塑料如何迁移到地下水中，许多先前的研究使用几微米或更小的人造微球作为模型来研究它们的运移。然而，在环境中观察到的微塑料在尺寸、形状和类型上更加多样，这可能具有不同的迁移行为。在这项工作中，研究了不规则形状的聚乙烯（PE）颗粒在填充砂柱中的运移。小的微塑料（22 - 37微米）通常比大的微塑料（44 - 74微米）具有更高的迁移率，但也会受到老化的影响。老化降低了微塑料的疏水性并增加了其表面负电荷，这可以促进微塑料的运移。然而，多孔介质中空间的物理屏障可能对它们的运移有更大的影响。由于压缩导致孔径减小，微塑料的截留随着压力的增加而增强。这项研究的结果表明，具有环境特征的微塑料也可以在地下水中运移，但这个过程可能受不同因素控制，如物理截留和空间位阻。
