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

This research commentary shows that microplastics and nanoplastics are accumulating in fish that ingest plastic particles as or along with food. Observed impacts of plastic particle ingestion in fish include intestinal blockage, physical injury, change in behavior, and other major health issues.

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.

Plastic pollution is collecting in all parts of the ocean. One alarming place that plastic items and microplastic is collecting is in the deepest known ocean region of the planet, Challenger Deep.

Abstract: Plastic debris and marine microplastics are being discharged into the ocean at an alarming scale and have been observed throughout the marine environment. Here we report microplastic in sediments of the Challenger Deep, the deepest known region on the planet, abyssal plains and hadal trenches located in the Pacific Ocean (4900 m–10,890 m). Microplastic abundance reached 71.1 items per kg dry weight sediment. That high concentrations are found at such remote depths, knowing the very slow sinking speed of microplastics, suggests that supporting mechanisms must be at-play. We discuss cascading processes that transport microplastics on their journey from land and oceanic gyres through intermediate waters to the deepest corners of the ocean. We propose that hadal trenches will be the ultimate sink for a significant proportion of the microplastics disposed in the ocean. The build-up of microplastics in hadal trenches could have large consequences for fragile deep-sea ecosystems.

Researchers find that plastics have a serious and complex impact on freshwater ecosystems that is often overlooked by the impacts of plastics on marine ecosystems. They suggest urgent action be taken to address this urgent global crisis. Learn more about these impacts.

Abstract: Plastics are dominant pollutants in freshwater ecosystems worldwide. Scientific studies that investigated the interaction between plastics and freshwater biodiversity are incipient, especially if compared to the marine realm. In this review, we provide a brief overview of plastic pollution in freshwater ecosystems around the world. We found evidence of plastic ingestion by 206 freshwater species, from invertebrates to mammals, in natural or semi-natural ecosystems. In addition, we reported other consequences of synthetic polymers in freshwater ecosystems—including, for instance, the entanglement of animals of different groups (e.g., birds). The problem of plastic pollution is complex and will need coordinated actions, such as recycling programs, correct disposal, stringent legislation, regular inspection, replacement of synthetic polymers with other materials, and ecological restoration. Current information indicates that the situation in freshwater ecosystems may be as detrimental as the pollution found in the ocean, although highly underappreciated.

Scientists find microplastics in 24 out of 28 samples of cloud water collected atop Mount Tai in China. The plastics found include PET, PP, PE, and PS, which together are found in synthetic fibers, clothing and textiles, packaging, and face masks.

Abstract: Airborne microplastics (MPs) have the potential to travel a long distance and undergo several cloud processes through atmospheric transport. However, little is known about the interactions between MPs and clouds. Here, we present field evidence for the presence of abundant and various MPs in cloudwater samples collected at Mt. Tai (1545 m asl.) in eastern China, with an average concentration of 463 MP L–1 in cloudwater, i.e., 0.21 MP m–3 in air. The cloud MPs had a broad size range of 8–1542 μm with 60% being smaller than 100 μm and dominant shapes of fragments with diverse polymers and darker colors. The concentrations of MPs were influenced by cloud liquid water content, source regions, and trajectory height, while the shapes and sizes appeared to be associated with long-range transport or localized sources. The roughened surface of cloud MPs indicated photochemical aging, which likely increased their adsorption capability for toxic metals (e.g., Pb, Hg) as confirmed by laboratory photoaging and adsorption simulations in ambient air, ultrapure water, and cloudwater. More research is needed to understand microplastic–cloud interactions and the potential impacts on atmospheric metal cycles and cloud formation.

Scientists analyze the fecal matter of seven terrestrial animals in the UK to check for signs of plastic ingestion. They found plastic in four out of seven species looked at: the European hedgehog, wood mouse, field vole, and brown rat. The levels of plastic in the feces of these animals were consistent with those found in human studies. Researchers also found “biodegradable” plastics in the wild mammals’ feces, suggesting more research is needed to understand the persistence of plant-based plastics in the environment.

As human impact on Earth continues to increase, scientists have tracked the changes and monitor the health of the planet. Unfortunately, scientists have found that humans have pushed Earth outside of the safe operating space for the long-term survival of our species. Human use of fossil fuels and human destruction of biodiversity lie at the core of the damage being done—and threat to all.

Abstract: This planetary boundaries framework update finds that six of the nine boundaries are transgressed, suggesting that Earth is now well outside of the safe operating space for humanity. Ocean acidification is close to being breached, while aerosol loading regionally exceeds the boundary. Stratospheric ozone levels have slightly recovered. The transgression level has increased for all boundaries earlier identified as overstepped. As primary production drives Earth system biosphere functions, human appropriation of net primary production is proposed as a control variable for functional biosphere integrity. This boundary is also transgressed. Earth system modeling of different levels of the transgression of the climate and land system change boundaries illustrates that these anthropogenic impacts on Earth system must be considered in a systemic context.