Shape- and polymer-considered simulation to unravel the estuarine microplastics fate

Yichuan Zeng; Hua Wang; Dongfang Liang; Weihao Yuan; Yuhan Shen; Zilin Shen; Qihui Gu

doi:10.1016/j.jhazmat.2023.132679

Shape- and polymer-considered simulation to unravel the estuarine microplastics fate

J Hazard Mater. 2024 Jan 5:461:132679. doi: 10.1016/j.jhazmat.2023.132679. Epub 2023 Sep 29.

Authors

Yichuan Zeng¹, Hua Wang², Dongfang Liang³, Weihao Yuan⁴, Yuhan Shen⁵, Zilin Shen¹, Qihui Gu¹

Affiliations

¹ Key Laboratory of Integrated Regulation and Resource Development on Shallow Lake of Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China; College of Environment, Hohai University, Nanjing 210098, China.
² Key Laboratory of Integrated Regulation and Resource Development on Shallow Lake of Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China; College of Environment, Hohai University, Nanjing 210098, China. Electronic address: wanghua543543@163.com.
³ Department of Engineering, University of Cambridge, Cambridge CB2 1PZ, UK.
⁴ Nanjing Institute of Environmental Science, Ministry of Ecology and Environment, Nanjing 210042, China.
⁵ Dept. of Civil, Environmental and Geomatic Engineering, University College London, London WC1E 6BT, UK.

PMID: 37793263
DOI: 10.1016/j.jhazmat.2023.132679

Abstract

Environmental microplastics (MPs) constitute various sizes, polymers, and shape components. In estuaries, such differences are related to the reliability of assessing the seaward fate of MPs, aggregation hotspots, and ecological risks. This study sets the MP particle mass gradient using the shape factor and size probability density function to categorically estimate the MP load in the surface layer of the Yangtze River Estuary (YRE), which is the largest contributor of plastics to the sea. During the high plastic input period in July, the optimized estimated MP load through the surface layer of the YRE was 9766 kg/month, which was overestimated by 821 kg/month based on the empirical average particle mass. While tracking MP transport classified by shape and polymer type, the resuspension of MPs that accumulate in the intertidal zone cannot be neglected. The average relative error of the simulation was as low as 19.6% after including the abovementioned factors. Finally, the simulation results of the sensitive regions were extracted to assess the new MP risk index, which considers shape, abundance, and polymer type. By introducing these essential tools, this study helps to understand the fate of riverine MPs entering estuaries, where valuable opportunities for removing MPs exist before they spread to the oceans.

Keywords: Classified simulation; Microplastic fate; Particle shape; Polymer type; Size probability density function.