Widespread occurrence of microplastics in marine bays with diverse drivers and environmental risk. (October 2022)

• Record Type: Journal Article
• Authors: Liu, Dong; Guo, Zhao-Feng; Xu, Yao-Yang; Ka Shun Chan, Faith; Xu, Yu-Yao; Johnson, Matthew; Zhu, Yong-Guan
• Is Part Of: Environment international. Volume 168(2022)
• Publication Date: 2022-10
• Subjects: Microplastics -- External drivers -- Sedimentation -- Composition similarity -- Risk assessment -- Marine bays; Environmental protection -- Periodicals; Environmental health -- Periodicals; Environmental monitoring -- Periodicals; Environmental Monitoring -- Periodicals; Environnement -- Protection -- Périodiques; Hygiène du milieu -- Périodiques; Environnement -- Surveillance -- Périodiques; Environmental health; Environmental monitoring; Environmental protection; Periodicals; 333.705
• DOI: 10.1016/j.envint.2022.107483
• Languages: English
• ISSNs: 0160-4120

Abstract

Graphical abstract: Highlights: A data mining framework for analyzing microplastics in marine bays was developed. Higher levels of sedimental microplastics mainly occurred in East Asian bays. Influencing factors of microplastic distribution were identified. An environmental risk assessment system of sedimental microplastics was proposed. Microfibers should be given priority in mitigating environmental risk. 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.