What are Microplastics?

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Context:

A team of scientists in China recently found microplastics in the human heart for the first time.

Relevance:

GS III- Environment and Ecology

Dimensions of the Article:

Microplastics are tiny plastic debris that are smaller than 5 mm in length, tinier than even a grain of rice.

There are two types of microplastics:

Primary microplastics are tiny particles that are purposely designed as such for commercial use, like in cosmetics, nurdles-plastic pellets used in industrial manufacturing and in fibres from synthetic textiles like nylon.
Secondary microplastics are formed through the degradation of larger plastic items like bottles, fishing nets and plastic bags. This occurs through exposure to the environment, like radiation from the sun, wind and ocean waves.

It is not yet clear if these microplastics can cross over from the blood stream to deposit in organs and cause diseases.
The report point out that the human placenta has shown to be permeable to tiny particles of polystyrene ( 50, 80 and 24 nanometre beads).
Experiments on rats where its lungs were exposed to polystryrene spheres (20 nanometre) led to translocation of the nanoparticles to the placental and fetal tissue.
Oral administration of microplastics in rats led to accumulation of these in the liver, kidney and gut.
Further studies have to be carried out to really assess the impact of plastics on humans.

While microplastics have been found across the world, from the world’s deepest ocean floors to the peak of Mount Everest, researchers say that this is the first time that they have been found in freshly fallen snow in Antarctica.
It shows that the spread of microplastics is so widespread, that even the remotest and least habitable places in the world are now infested by these particles.
The presence of these particles can pose a huge threat to Antarctica’s distinctive ecosystem.
Microplastics are not biodegradable and once they are found in the environment, they begin to accumulate.
They can be toxic for plants and animals.
The report claims that ingestion of microplastics by various life forms in the region, from microorganisms like zooplankton to larger predators like king penguins can disrupt their usual biological processes and negatively impact the entire Antarctic food chain.
The presence of microplastics in Antarctica can also worsen the impact of climate change.
Ice sheets and glaciers are already rapidly melting, and the report suggests that the microplastics deposited in ice and snow can accelerate the melting of the cryosphere — regions where water is in solid form, like the planet’s North and South Poles.
Dark-coloured microplastics, which constituted 55% of the samples collected in Aves’ study, are even more harmful than lighter colours, as they are better at absorbing sunlight and retain more heat.

-Source: Hindustan Times