Guo Jia, Rong Haifeng, He Lei, Chen Cuibai, Zhang Baogang, Tong Meiping
MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, College of Water Resources and Environment, China University of Geosciences Beijing, Beijing 100083, PR China; The Key Laboratory of Water and Sediment Sciences, Ministry of Education, State Environmental Protection Key Laboratory of All Material Fluxes in River Ecosystems, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, P. R. China.
The Key Laboratory of Water and Sediment Sciences, Ministry of Education, State Environmental Protection Key Laboratory of All Material Fluxes in River Ecosystems, College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, P. R. China.
J Hazard Mater. 2024 Jun 5;471:134285. doi: 10.1016/j.jhazmat.2024.134285. Epub 2024 Apr 16.
Understanding the impact of arsenic (As(III), inorganic pollutant widely present in natural environments) on microplastics (MPs, one type of emerging contaminants) mobility is essential to predict MPs fate and distribution in soil-groundwater systems, yet relevant research is lacking. This study explored the effects of As(III) copresent in suspensions (0.05, 0.5, and 5 mg/L) on MPs transport/attachment behaviors in porous media containing varied water contents (θ = 100 %, 90 %, and 60 %) under different ionic strengths (5, 10, and 50 mM NaCl) and flow rates (2, 4, and 8 m/day). Despite solution ionic strengths, flow rates, porous media water contents, sizes, and surface charges of MPs, with coexisting humic acid, and in actual water samples, As(III) of three concentrations increased MPs transport in quartz sand and natural sandy soil. The increased electrostatic repulsion between MPs and sand caused by the altered MPs surface charge via the adsorption of As(III) together with steric repulsion from As(III) in solution contributed to the promoted MPs mobility in porous media. The occupying attachment sites by As(III) partially contributed to the increased mobility of MPs with negative surface charge in porous media. Clearly, As(III) coexisting in suspensions would enhance MPs transport in porous media, increasing MPs environment risks.
了解砷（III价无机污染物，广泛存在于自然环境中）对微塑料（新兴污染物之一）迁移率的影响，对于预测微塑料在土壤-地下水系统中的归宿和分布至关重要，但相关研究仍很缺乏。本研究探讨了悬浮液中不同浓度（0.05、0.5和5 mg/L）的As(III)在不同离子强度（5、10和50 mM NaCl）和流速（2、4和8 m/天）下，对含不同含水量（θ = 100%、90%和60%）的多孔介质中微塑料传输/附着行为的影响。尽管存在溶液离子强度、流速、多孔介质含水量、微塑料的尺寸和表面电荷、腐殖酸共存以及实际水样等因素，但三种浓度的As(III)均增加了石英砂和天然砂土中微塑料的传输。As(III)吸附改变微塑料表面电荷，导致微塑料与砂粒之间静电斥力增加，同时溶液中As(III)的空间位阻斥力共同促进了微塑料在多孔介质中的迁移。As(III)占据附着位点部分导致了表面带负电的微塑料在多孔介质中迁移率增加。显然，悬浮液中共存的As(III)会增强微塑料在多孔介质中的传输，增加微塑料的环境风险。
