Key Laboratory of Integrated Regulation and Resource Development on Shallow Lake of Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, People's Republic of China.
Jiangsu Province Water Resources Planning Bureau, 210029, People's Republic of China.
Environ Pollut. 2020 Aug;263(Pt B):114499. doi: 10.1016/j.envpol.2020.114499. Epub 2020 Apr 2.
The long-term contamination of soil by microplastics may pose risks that are often still not well understood, and the ecological effects of microplastics are mainly dependent on their environmental behavior in environments. This study used saturated quartz sand as a solid porous medium to study the migration and influencing factors of 40-48 μm polyethylene (PE) particles in saturated porous media. The breakthrough curves at different injection concentrations (0.3, 0.4, 0.5 mg/L), flow rates (1.0, 1.5, 2.0, 2.5 ml/L), porous medium particle sizes (1-2, 2-4 mm), ionic strengths (0, 0.01, 0.05 mol/L) and concentrations of fulvic acid (FA) (0, 5, 10 mg/L) were compared and analyzed. The Derjaguin-Landau-Verwey-Overbeek (DLVO) theory was used to more accurately explain relevant transport behaviors. The results showed that the input concentration, flow rate, and particle size can affect the migration of PE particles individually or in combination. As ionic strength increased, the repulsion between microplastics and quartz sand gradually disappeared according to DLVO theory, and their attraction gradually strengthened. As a result, fewer microplastics could penetrate the sand column and reach the water body. With the continuous addition of FA, the repulsive energy between microplastics and quartz sand rose from DLVO theory, and the migration ability of microplastics initially increased before becoming stable because of the effect of straining. In all cases, the migration ability of PE was low (C/C < 0.35), and most PE particles remained in the porous media during the whole experimental periods. This study provides new insights of understanding the migration of microplastics in environment.
土壤中长期存在的微塑料可能会带来风险，而这些风险往往还没有被很好地理解，微塑料的生态效应主要取决于它们在环境中的环境行为。本研究使用饱和石英砂作为固体多孔介质，研究了 40-48μm 聚乙烯（PE）颗粒在饱和多孔介质中的迁移和影响因素。在不同注入浓度（0.3、0.4、0.5mg/L）、流速（1.0、1.5、2.0、2.5ml/L）、多孔介质颗粒大小（1-2、2-4mm）、离子强度（0、0.01、0.05mol/L）和富里酸（FA）浓度（0、5、10mg/L）下，比较和分析了穿透曲线。采用德加古因-朗道-范韦尔韦克（DLVO）理论更准确地解释了相关的输运行为。结果表明，输入浓度、流速和粒径单独或组合都可以影响 PE 颗粒的迁移。随着离子强度的增加，根据 DLVO 理论，微塑料和石英砂之间的排斥力逐渐消失，吸引力逐渐增强。结果，更少的微塑料可以穿透砂柱并进入水体。随着 FA 的不断添加，微塑料和石英砂之间的排斥能从 DLVO 理论上升，微塑料的迁移能力最初增加，然后由于过滤作用而变得稳定。在所有情况下，PE 的迁移能力都较低（C/C<0.35），并且在整个实验期间，大部分 PE 颗粒仍留在多孔介质中。本研究为理解微塑料在环境中的迁移提供了新的见解。
