Depth profiles of microplastics in sediments from inland water to coast and their influential factors

Bing Yuan; Wenhui Gan; Jian Sun; Binliang Lin; Zhihe Chen

doi:10.1016/j.scitotenv.2023.166151

Depth profiles of microplastics in sediments from inland water to coast and their influential factors

Sci Total Environ. 2023 Dec 10:903:166151. doi: 10.1016/j.scitotenv.2023.166151. Epub 2023 Aug 9.

Authors

Bing Yuan¹, Wenhui Gan², Jian Sun³, Binliang Lin⁴, Zhihe Chen⁵

Affiliations

¹ School of Civil Engineering, Sun Yat-sen University, 519082 Zhuhai, China; State Key Laboratory of Hydroscience and Engineering, Department of Hydraulic Engineering, Tsinghua University, 100084 Beijing, China.
² School of Civil Engineering, Sun Yat-sen University, 519082 Zhuhai, China.
³ State Key Laboratory of Hydroscience and Engineering, Department of Hydraulic Engineering, Tsinghua University, 100084 Beijing, China. Electronic address: jsun@mail.tsinghua.edu.cn.
⁴ State Key Laboratory of Hydroscience and Engineering, Department of Hydraulic Engineering, Tsinghua University, 100084 Beijing, China.
⁵ School of Civil Engineering, Sun Yat-sen University, 519082 Zhuhai, China. Electronic address: chzhihe@mail.sysu.edu.cn.

PMID: 37562610
DOI: 10.1016/j.scitotenv.2023.166151

Abstract

Microplastics, plastic particles with a size smaller than 5 mm, are widely observed in the global environments and pose a growing threat as they accumulate and affect the environments in numerous ways. These particles can be transported from inland water to coast and disperse from surface water to deep sediments, especially the latter, while knowledge of the hidden microplastics in sediment layers is still lacking. Understanding the characteristics and behavior of microplastics in deep sediments from inland water to coast is crucial for estimating the present and future global plastic budget from land to seas. Herein, present knowledge of microplastic sedimentation from inland water to coast is reviewed, with a focus on the physical characteristics of microplastics and environmental factors that affect sedimentation. The abundance, shape, composition, and timeline of microplastics in sediment layers in rivers, floodplains, lakes, estuaries and coastal wetlands are presented. The abundance of microplastics in sediment layers varies across sites and may exhibit opposite trends along depth, and generally the proportion of relatively small microplastics increases with depth, while less is known about the vertical trends in the shape and composition of microplastics. Timeline of microplastics is generally linked to the sedimentation rate, which varies from millimeters to centimeters per year in the reviewed studies. The spatiotemporal characteristics of microplastic sedimentation depend on the settling and erosion of microplastics, which are determined by two aspects, microplastic characteristics and environmental factors. The former aspect includes size, shape and density influenced by aggregation and biofouling, and the latter includes dynamic forces, topographic features, bioturbation and human activities. The comprehensive review of these factors highlights the needs to further quantify the characteristics of microplastic sedimentation and explore the role of these factors in microplastic sedimentation on various spatiotemporal scales.

Keywords: Dynamic forces; Layered sediment; Microplastics; Settling and erosion; Timeline.

Publication types

Review