Widespread occurrence of microplastics in marine bays with diverse drivers and environmental risk

Dong Liu; Zhao-Feng Guo; Yao-Yang Xu; Faith Ka Shun Chan; Yu-Yao Xu; Matthew Johnson; Yong-Guan Zhu

doi:10.1016/j.envint.2022.107483

Widespread occurrence of microplastics in marine bays with diverse drivers and environmental risk

Environ Int. 2022 Oct:168:107483. doi: 10.1016/j.envint.2022.107483. Epub 2022 Aug 18.

Authors

Dong Liu¹, Zhao-Feng Guo¹, Yao-Yang Xu², Faith Ka Shun Chan³, Yu-Yao Xu⁴, Matthew Johnson⁵, Yong-Guan Zhu⁶

Affiliations

¹ Key Laboratory of Urban Environment and Health, Ningbo Observation and Research Station, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, Peoples Republic China; University of Chinese Academy of Sciences, Beijing 100049, Peoples Republic China; Zhejiang Key Laboratory of Urban Environmental Processes and Pollution Control, CAS Haixi Industrial Technology Innovation Center in Beilun, Ningbo 315830, Peoples Republic China.
² Key Laboratory of Urban Environment and Health, Ningbo Observation and Research Station, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, Peoples Republic China; Zhejiang Key Laboratory of Urban Environmental Processes and Pollution Control, CAS Haixi Industrial Technology Innovation Center in Beilun, Ningbo 315830, Peoples Republic China. Electronic address: yyxu@iue.ac.cn.
³ School of Geographical Sciences, Faculty of Science and Engineering, University of Nottingham Ningbo China, Ningbo 315100, Zhejiang, Peoples Republic China; School of Geography, University of Leeds, Leeds LS2 9JT, UK; Water@Leeds Research Institute, University of Leeds, Leeds LS2 9JT, UK.
⁴ School of Geographical Sciences, Faculty of Science and Engineering, University of Nottingham Ningbo China, Ningbo 315100, Zhejiang, Peoples Republic China.
⁵ School of Geography, University of Nottingham, University Park, NG7 2RD Nottingham, UK.
⁶ Key Laboratory of Urban Environment and Health, Ningbo Observation and Research Station, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, Peoples Republic China; Zhejiang Key Laboratory of Urban Environmental Processes and Pollution Control, CAS Haixi Industrial Technology Innovation Center in Beilun, Ningbo 315830, Peoples Republic China.

PMID: 36001911
DOI: 10.1016/j.envint.2022.107483

Abstract

Microplastic contamination in the sediment of marine bays has attracted widespread attention, whereas the distribution, sedimentation, morphology and risk of microplastics at regional scale remain poorly understood. By introducing a data mining framework into microplastic research, we compiled a microplastic dataset of 649 samples from 24 bays to enhance the understanding of geographical difference and drivers, transfer, composition profile and environmental risk of sedimental microplastics. Microplastic abundance varied from 0.72 to 1963.96 items/kg dry weight, with higher concentrations mainly occurring in East Asian bays. The spatial pattern in abundance was driven by the river plastic emissions, aquaculture production and hydrodynamic condition. A significantly positive correlation between microplastic abundance in water and sediment was found, and microplastic sedimentation was related to polymer density, hydrodynamic conditions and sediment properties. The dominant shape and polymer of sedimental microplastics were fiber and polypropylene, respectively, and the similarity of microplastic composition decreased with increasing geographical distance. The environmental risks of microplastics were partitioned into three classes (Rank II-Rank IV) with a two-dimensional assessment system considering the bioavailability and toxicity of microplastics, and Asian bays were identified as potential high-risk areas. To reduce the environmental risk of sedimental microplastics in bays, priority should be given to the removal of microfibers, and control measures depend on the risk classes and dominant polymers. Microplastic abundance and composition were significantly affected by methodological choices regarding sampling, pretreatment and identification, suggesting a unified methodology is essential to further enhance our knowledge on the distribution and risk of microplastics in marine bays.

Keywords: Composition similarity; External drivers; Marine bays; Microplastics; Risk assessment; Sedimentation.