Beach garbage photographed by the Australian team during the investigation. Image source: Nature Research

Today's Viewpoint

Reporter Zhang Mengran

This is probably a battle of the century.

Since the 1950s, human demand has caused the production of plastics to double exponentially. Today, even though we have realized that plastics are everywhere, humans still rely on them infinitely. At present, 500 billion plastic bags are still consumed worldwide every year, and 1 million plastic bottles are still sold every minute...These plastics disappear easily, flow into the sea, and soon fade out of our sight.

But in fact, most of them will always exist, like ghosts, and re-bind with humans in various ways.

Plastic particles travel far with the wind

Recently, the French National Center for Scientific Research 5245 Research Mixed Unit published a study saying that plastic particles can pass through the atmosphere and reach areas far away from the initial emission source, and even some pristine areas.

These plastic particles are very small pieces of plastic waste that can be found in rivers, oceans and pristine polar regions. Past studies have shown that plastic particles can flow all the way into the ocean along rivers, affecting aquatic ecosystems along the way.

But people do not believe that plastic particles can be transported through the atmosphere and enter undeveloped areas, and there has been a lack of relevant research before.

Scientist Dionne Allen and his colleagues conducted a five-month survey of a remote mountain catchment area in the French Pyrenees. They collected dry and wet sediment samples from the atmosphere during five sampling cycles and found a large number of plastic particles, including plastic fragments, films and fiber fragments. The daily deposition rate of plastic particles they measured was 365 particles per square meter.

Surprisingly, atmospheric simulations showed that these plastic particles were transported from at least 100 kilometers away through the atmosphere.

They published their research in Nature Geoscience. The conclusion is that the transportation of "atmospheric channels" may be an important way for plastic particles to reach and affect the original area.

Marine plastic has reached a scale

Human activities and garbage discharge have caused a large amount of plastic to flow into the ocean, and the large ones will eventually decompose into microparticles. However, in the sea ice, which was once thought to be extremely pure, there are already trillions of plastic microparticles - 240 plastic microparticles per cubic meter of sea ice, which is about 2,000 times the density of plastic microparticles in the Great Pacific Garbage Patch.

The Alfred Wegener Institute for Polar and Marine Research in Germany analyzed that the distribution of plastic microparticles in the central Arctic Ocean is very complex, and the plastic microparticles released by the melting of sea ice will easily "occupy" deep water areas, be eaten by filter-feeding animals in the ocean, remain in their bodies, and then pass through the food chain.

In addition, through the plastic entanglement records on an ocean sampler, scientists from the British Marine Biological Society recently counted the data on the appearance of marine plastics from 1957 to 2016. This latest report said that judging from the amount of plastic in the North Atlantic and adjacent waters alone, the growth has exceeded expectations since the 1990s.

Since 1957, the sampler has been towed more than 6.5 million nautical miles in the North Atlantic and adjacent waters, helping the team confirm the growth of plastic in the high seas from the 1990s to the present. It was found that plastic entanglements have increased 10 times since 2000!

Among them, plastics related to human fisheries (such as fishing nets) have contributed the most to the growth of plastics in the past 20 years. Meanwhile, in the infamous Pacific Garbage Patch, 99.9% of the waste is plastic, of which at least 46% is fishing nets.

Mountains of waste on remote islands

In another study, scientists set their sights on remote islands far from the coast for the first time.

A team from the University of Tasmania in Australia found that in 2017 alone, an estimated 414 million pieces of human-made waste were distributed on the remote Cocos (Keeling) Islands, including plastics, foam, metals and glass, with a total weight of 238 tons.

This is the conclusion of a comprehensive survey of macro- and micro-trash on 25 beaches across seven islands in the archipelago. The team found that micro-trash accounted for more than 60% of all the trash on the beaches. Shoes and disposable consumer products (such as food packaging bags, beverage bottles, straws and toothbrushes) accounted for nearly 25% of the identifiable trash.

And of all the trash recorded by the researchers, plastic products accounted for more than 95%.

The researchers estimated that 338,355,473 pieces of trash were buried 1-10 cm below the beach surface, which is 26 times the amount of trash visible on the beach (estimated to be about 12,868,379 pieces)! As most previous global trash surveys have only focused on beach trash, these surveys may have seriously underestimated the scale of the trash accumulation.

Given this alarming number, the researchers believe that a multi-pronged approach is urgently needed to prevent more plastic products from entering the ocean, such as actively adopting strategies to limit plastic production and consumption, a universal ban on disposable products, and truly effective waste management.

(Science and Technology Daily, Beijing, May 22)

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