Effects of waves, burial depth and material density on microplastic retention in coastal sediments

Nanhao Xu; Zhenchang Zhu; Weilun Gao; Dongdong Shao; Shaorui Li; Qin Zhu; Zhongya Fan; Yanpeng Cai; Zhifeng Yang

doi:10.1016/j.scitotenv.2022.161093

Effects of waves, burial depth and material density on microplastic retention in coastal sediments

Sci Total Environ. 2023 Mar 15:864:161093. doi: 10.1016/j.scitotenv.2022.161093. Epub 2022 Dec 22.

Authors

Nanhao Xu¹, Zhenchang Zhu², Weilun Gao¹, Dongdong Shao³, Shaorui Li¹, Qin Zhu⁴, Zhongya Fan⁵, Yanpeng Cai⁶, Zhifeng Yang⁶

Affiliations

¹ Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou 510006, China.
² Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou 510006, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China. Electronic address: zhenchang.zhu@gdut.edu.cn.
³ State Key Laboratory of Water Environment Simulation and School of Environment, Beijing Normal University, Beijing, China.
⁴ Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China.
⁵ South China Institute of Environmental Sciences, Ministry of Ecology and Environment, No. 18 Ruihe Road, 510530 Guangzhou, China.
⁶ Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou 510006, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China.

PMID: 36566860
DOI: 10.1016/j.scitotenv.2022.161093

Abstract

Coastal sediments, recognized as a major sink for microplastics (MPs), are subject to frequent physical disturbances, such as wave disturbance and associated sediment dynamics. Yet it remains poorly understood how wave disturbance regulates MPs accumulation in such a dynamic environment. Here, we examined the effects of waves and their interactions with material density and burial depth on the retention of MPs in coastal sediments, through manipulative experiments in a mangrove habitat along the coast of South China. The results clearly revealed that stronger waves removed more buried MPs from the sediments. Moreover, storms can have disproportional effects on MPs retention by inducing large waves and strong sediment erosion. We also demonstrated that MPs retention generally increased linearly with growing material density and non-linearly with raised burial depth in the sediment. Overall, our findings highlight the importance of both external and internal factors in shaping MPs retention in coastal ecosystems like mangroves, which is essential to assess and predict MPs accumulation patterns as well as its impacts on ecosystem functioning of such blue carbon habitats.

Keywords: Burial depth; Density; Microplastics; Retention; Waves.