Distribution and translocation of micro- and nanoplastics in fish

Abstract

Microplastics (MPs) and nanoplastics (NPs) are regarded as emerging particulate contaminants. Here, we first summarize the distribution of plastic particles in fish. Field investigations verify the presence of various kinds of fibrous, spherical, and fragmentary MPs in fish gastrointestinal tract and gills, and specifically in muscle and liver. Laboratory works demonstrate that NPs even penetrate into blood vessels of fish and pass onto next generations. Second, we systematically discuss the translocation ability of MPs and NPs in fish. MPs can enter early-developing fish through adherence, and enter adult fish internal organs by intestine absorption or epidermis infiltration. NPs can not only penetrate into fish embryo blastopores, but also reach adult fish internal organs through blood circulation. Third, the cellular basis for translocation of plastic particles, NPs in particular, into cells are critically reviewed. Endocytosis and paracellular penetration are two main pathways for them to enter cells and intercellular space, respectively. Finally, we compare the chemical and physical properties among various particular pollutants (MPs, NPs, settleable particulate matters, and manufactured nanomaterials) and their translocation processes at different biological levels. In future studies, it is urgent to break through the bottleneck techniques for NPs quantification in field environmental matrix and organisms, re-confirm the existence of MPs and NPs in field organisms, and develop more detailed translocating mechanisms of MPs and NPs by applying cutting-edge tracking techniques.

Keywords:

• Microplastics
• nanoplastics
• fish
• distribution
• translocation
• particular pollutants

Acknowledgments

The authors gratefully acknowledge the constructive comments of the anonymous reviewers. The authors also thank Dayong Wang (Southeast University, China), Liping Ma (East China Normal University, China), Youji Wang (Shanghai Ocean University, China) and Yan Zhang (Nanjing University, China) for their suggestions to the present manuscript.

Declaration of interest

The authors’ affiliation is as shown on the cover page. All of the authors are from universities and have studied microplastics for several years. They all participated in the discussion and revision writing of this manuscript. The authors have sole responsibility for the writing and content of this paper.

Additional information

Funding

This project is supported by the National Natural Science Foundation of China under Grant [41977344; 21806038]. None of the authors have participated in any legal, regulatory or advocacy proceedings related to the contents of the paper. The authors report there are no competing interests to declare.