Ingestion of microplastics by fish and its potential consequences from a physical perspective

Abstract

The European Marine Strategy Framework Directive and the United States Microbead Free Waters Act are credited for being ambitious in their goals for protecting the marine environment from microplastics pollution. As a result, the microplastic pollution of marine environments and the incidence of microplastic ingestion by fish is rapidly receiving an increase in overdue attention. This commentary summarizes recent discoveries regarding the potential negative effects of micro- and nanoplastic ingestion by fish. Analysis shows that the occurrence of microplastics in the gastrointestinal tract of fish is ephemeral, with low accumulation potential in the gastrointestinal tract, although translocation to the liver may occur. Nevertheless, the total load of micro- and nanoplastics that will pass through the gastrointestinal tract of a fish in its lifetime is likely high and will keep increasing in the future. This may pose a risk because there is evidence that micro- and nanoplastic ingestion can interfere with fish health. Observed effects of microplastics ingestion include (but are not necessarily limited to) intestinal blockage, physical damage, histopathological alterations in the intestines, change in behavior, change in lipid metabolism, and transfer to the liver. Integr Environ Assess Manag 2017;13:510–515. © 2017 SETAC Key Points: The mass of plastic in certain parts of some oceans is already surpassing the mass of plankton, and in the relatively near future, plastic will surpass fish stocks in the oceans by weight while the count of plastic micro- and nanoparticles will be considerably greater than the count of plankton. Occurrence of microplastics in the gastrointestinal tract of fish is ephemeral, with low accumulation potential in the gastrointestinal tract, although translocation to the liver may occur. Ingestion of micro- and nanoplastics by fish may lead to physical blockage of the digestive organs and interference with feeding, change in behavior, mechanical injury, histopathological alterations in intestinal tract and liver, and change in lipid metabolism among other problems. Both microplastics quantity and ingestion frequency by fish will rise in the future as the input of microplastics in marine environment is increasing, whereas the cost of ocean cleanup operations from plastic litter is very high and microplastics cleanup, in particular, is highly unfeasible.