Explained: Why is the discovery of microplastics in fresh Antarctic snow troubling?

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For the first time, microplastics have been found in freshly fallen snow in Antarctica. The pollutant, scientists argue, poses a growing threat to the region’s ecosystem and could increase the melting of ice and snow.

Alex Aves, a PhD student from the University of Canterbury in New Zealand, collected snow samples from 19 sites in the Ross Island region of Antarctica and found that all contained microplastics. The research was published in a peer-reviewed article in a scientific journal, The Cryosphere on June 7.

While microplastics have been found across the world, from the world’s deepest ocean floors to the peak of Mount Everest, researchers say this is the first time they have been found in freshly fallen snow in Antarctica.

What are microplastics?

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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 fibers 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.

How did they reach Antarctica?

The study found an average of 29 microplastic particles per liter of melted snow.

These particles, due to their light weight and low density, might have traveled through air from more than 6,000 km away. However, researchers argued that there is also a possibility that the human presence in Antarctica created a microplastic ‘footprint’.

Of the 13 different plastic types found, the most common was polyethylene terephthalate (PET), a type of plastic used in everyday items such as clothes, plastic bottles, packaging etc. PET was found in 79 per cent of all samples.

The most likely sources of the airborne microplastic are local research stations, due to the clothing worn by staff, broken fragments of plastic equipment and mismanaged waste. There was a much larger concentration of microplastics (nearly 3 times higher) in the samples next to local base camps, such as Scott Base and McMurdo Station in Ross Island, as compared to those from more remote sites.

Wayfinding flags, made of synthetic polyamide fabric which identify safe routes for travel, might also release microplastic, according to the report.

Why is this discovery troubling?

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 to 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-colored microplastics, which constituted 55% of the samples collected in Aves’ study, are even more harmful than light colors, as they are better at absorbing sunlight and retain more heat.

Further, the study shows the ubiquitous presence of microplastics in not only land and water, but the air as well.

When snow travels in the atmosphere, it binds itself to airborne particles and pollutants, which are then deposited on Earth’s surfaces. This phenomenon is called “scavenging” and according to scientists is a significant way in which microplastics are able to travel and further pollute land and water. When carried by snow, rain and wind, they can also lead to the risk of possible inhalation of microplastics by humans and wildlife.

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