Contrasting effects of microplastics on sorption of diazepam and phenanthrene in soil

Baile Xu; Dan Huang; Fei Liu; David Alfaro; Zhijiang Lu; Caixian Tang; Jay Gan; Jianming Xu

doi:10.1016/j.jhazmat.2020.124312

Contrasting effects of microplastics on sorption of diazepam and phenanthrene in soil

J Hazard Mater. 2021 Mar 15:406:124312. doi: 10.1016/j.jhazmat.2020.124312. Epub 2020 Oct 20.

Authors

Baile Xu¹, Dan Huang², Fei Liu³, David Alfaro⁴, Zhijiang Lu², Caixian Tang⁵, Jay Gan⁴, Jianming Xu⁶

Affiliations

¹ Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China; Department of Environmental Sciences, University of California, Riverside, 900 University Avenue, Riverside, CA 92521, USA.
² Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China.
³ Institute of Environmental Research at Greater Bay, Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Guangzhou University, 230 Wai Huan Xi Road, Guangzhou 510006, China.
⁴ Department of Environmental Sciences, University of California, Riverside, 900 University Avenue, Riverside, CA 92521, USA.
⁵ Department of Animal, Plant and Soil Sciences, La Trobe University, Melbourne Campus, Bundoora, VIC 3086, Australia.
⁶ Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China. Electronic address: jmxu@zju.edu.cn.

PMID: 33144003
DOI: 10.1016/j.jhazmat.2020.124312

Abstract

Microplastics have attracted extensive attention regarding their role in the cycling of organic pollutants in aquatic environments. However, the influence of microplastics on the sorption of organic pollutants in soil is unclear. Herein, we investigated the sorption of polar diazepam and nonpolar phenanthrene to two soils (Inceptisol and Oxisol). Batch sorption experiments were used to evaluate the effect of polyethylene (PE), polypropylene (PP), and polystyrene (PS) microplastics at addition rates of 0.1%, 1%, and 10% (w/w). The addition of microplastics significantly decreased the overall sorption of diazepam at 10%, and increased the sorption of phenanthrene at 1%, while the effects were negligible at other addition rates. Decreased sorption of diazepam was attributed to its lower sorption affinity to microplastics than to soil. Microplastics, even at 0.1%, substantially decreased the relative distribution of phenanthrene in soil, particularly for PE in the Oxisol with lower f_oc. The sorption affinity of phenanthrene followed the order PE > soil organic carbon (SOC) > PP > PS, suggesting that PE can be a significant sink of phenanthrene in contaminated soils. Overall, microplastics can change the sorption of diazepam and phenanthrene to soil and therefore affect their mobility and environmental risk in soil ecosystems.

Keywords: Distribution; Polyethylene; Polypropylene; Polystyrene; Soil organic carbon.

Publication types

Research Support, Non-U.S. Gov't