Effects of arsenic on the transport and attachment of microplastics in porous media

Jia Guo; Haifeng Rong; Lei He; Cuibai Chen; Baogang Zhang; Meiping Tong

doi:10.1016/j.jhazmat.2024.134285

Effects of arsenic on the transport and attachment of microplastics in porous media

J Hazard Mater. 2024 Jun 5:471:134285. doi: 10.1016/j.jhazmat.2024.134285. Epub 2024 Apr 16.

Authors

Jia Guo¹, Haifeng Rong², Lei He², Cuibai Chen³, Baogang Zhang³, Meiping Tong⁴

Affiliations

¹ 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.
² 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.
³ MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, College of Water Resources and Environment, China University of Geosciences Beijing, Beijing 100083, PR China.
⁴ 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. Electronic address: tongmeiping@pku.edu.cn.

PMID: 38640672
DOI: 10.1016/j.jhazmat.2024.134285

Abstract

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.

Keywords: Arsenic; Microplastics; Mobile capability; Porous media; Steric repulsion.