Researchers at the University of Canterbury in New Zealand have discovered microplastics for the first time in new snowfall in Antarctica.
According to a paper published in the journal Cryosphere, the particles contain 13 plastic components, including PET, the most common used to make beverage bottles and clothes, and the researchers believe that microplastics may pose a risk to the Antarctic food chain.
The ocean is home to the world's largest concentration of plastic waste, and fish and birds often mistake microplastics for food.
Source: Network
Ninety percent of more than 20 common economic fish species have microplastics in their bodies, and 80% of Antarctic birds have microplastics in their stomachs.
So far, plastic has been found in every corner of the earth, and Antarctica, which has been called the "cleanest" place on the planet by researchers, is still not immune.
It is estimated that the global average person ingests about 107 microplastics per year, which is equivalent to swallowing a credit card every week.
What exactly is microplastic pollution?
How did it run rampant all over the world, how did it climb onto the table and be eaten by us?
And the ubiquitous microplastics, do we really can't help it?
01
Microplastics have not spared any piece of earth
Between November 30 and December 2, 2019, to confirm the distribution of microplastics in Antarctica, researchers collected 19 samples from various locations in Ross Island, Antarctica, and a total of 109 particles were identified as microplastics;
Especially in the scientific base next to Ross Island, Scott Base and McMurdo Station, the largest in Antarctica, the density of microplastics is almost 3 times higher.
This is the first time such a scale has been studied in Antarctica, but during two expeditions with the research vessel Polarstern in 2018 and 2019, researchers collected 34 surface water samples and 79 groundwater samples, filtering a total of about 8 million liters of seawater and finding microplastics in them.
Early research on microplastics in Antarctica was conducted in areas with high levels of research stations, shipping traffic and personnel, and more recently in the Southern Ocean research and citizen science projects reported on microplastics in deep-sea sediments and surface water; A foundation found microplastics in all four samples collected using trawls in the Southern Ocean.
There are already vast amounts of microplastics in the world's marine ecosystems, from the tropics to Arctic sea ice and now the Southern Ocean.
How exactly do microplastics achieve "world travel"?
Microplastic particles enter the ocean through two channels, one of which is wastewater.
In Antarctic waters, for example, wastewater discharged from scientific research stations and research, fishing and tourist vessels contains microplastics.
Traditional wastewater treatment, including tertiary treatment techniques such as microfiltration, may not completely remove microplastics, a situation that may be exacerbated in remote polar regions, as operational difficulties can reduce treatment efficiency.
This method of wastewater treatment is already very backward, and a report found that 52% of the 71 research stations in Antarctica do not have a wastewater treatment system, which makes the pollution worse.
The other is through the decomposition of large plastics into microplastics, which then enter the ocean.
Numerous studies have shown that microplastic particles persist in marine systems, accumulating in ocean circulation, including surface and deep-sea waters and deep-sea sediments, and eventually entering deep-sea and deep-sea sediments and animals worldwide.
Studies have found that there are primary and secondary sources of marine microplastic pollution.
There are many sources of primary microplastics, such as personal care products such as toothpaste, shampoo and shower gel, and fibers from laundries that may release microplastic fibers from wastewater.
Studies have shown that a polyester wool jacket can release more than 1,900 fibers per wash, of which about 90% of the microplastics may be retained in sewage treatment plants, and microplastics can "smoothly pass" through sewage treatment facilities and be released into the nearshore marine environment in a largely unchanged state.
Secondary microplastic pollution, including particles and fibers, is produced by the decomposition of macroscopic ocean plastic debris and is also common in oceans around the world.
About half of the waste plastic floats in seawater and can therefore be degraded by ultraviolet (UV) radiation and decomposition. Several comprehensive studies evaluating the ocean near densely populated areas found that secondary sources are the most "contributing" primary and secondary microplastics to the overall microplastic levels in the marine environment.
Secondary microplastics are known to be found in the surface layers of oceans and deep-sea waters, as well as in deep-sea sediments in the world's oceans. A recent global assessment indicates that about 6.4 million tonnes of plastic flows into the ocean each year, and about 5 million solid waste is thrown off or dropped from ships.
Antarctic microplastic pollution has never been an isolated case, but it exposes the seriousness of this pollution.
02
Plastic waste going around in circles
The major current systems in the Southern Ocean include the eastward Antarctic Circumpolar Current, the westward Antarctic Coastal Current, and the clockwise Wedel and Ross circulations.
The polar front in the circulation was once considered by researchers to stop the spread of microplastic pollution because it can block the exchange of materials at low latitudes.
But in reality, the polar front produces vortices that transfer material southward, and in areas like the western Antarctic Peninsula, the polar front is close to the Antarctic continent, allowing seawater from low latitudes to be transferred to the nearshore environment through shorter pathways.
Material south of the polar front can be transferred to the Antarctic continent through branches of regional circulation flowing south, such as in the Weddell Sea and Ross Sea, where interaction with the Antarctic coastal current can lead to further diffusion.
This will affect four habitats in the Southern Ocean, namely the pelagic zone, the benthic zone, the nearshore zone and the intertidal zone, where the food web is fluid, unstable, and has rapid turnover, all of which are affected by microplastics to varying degrees.
According to experiments using high concentrations of microplastics, in zooplankton communities, filter feeders are expected to consume a large proportion of food because their predation is to filter food from large amounts of water, while microplastics may disrupt zooplankton biological processes and affect Antarctic krill, which form the basis of the continent's food chain.
Antarctic krill is an important ecological filter feeder, its population distribution is uneven in space and time, about 25% of the biomass is concentrated in 10% of its total habitat area, namely the Scotia Sea and Drake Sound.
The Scotia Sea is one of the high-flow areas for shipping in the region and may be a key area for krill ingestion of microplastics.
Evidence from the Northern Hemisphere suggests that microplastics may have toxicological effects on pelagic ecosystems through key species at the bottom of the food chain, as well as through the food chain.
These processes can negatively affect higher predators such as fish, seabirds, seals, and whales.
Just by looking at marine life, it is not difficult to understand why microplastics can be on the human table and ingested into the body. For the treatment of microplastic pollution, it is imperative, not only to eat less plastic, but also to purify the marine environment.
This "appetite" for polystyrene worms could be the key to recycling plastics on a large scale, and scientists hope that this "upgraded" biological cycle will lead to new ways of recycling plastic waste, thereby reducing the amount of waste to landfill.
Protecting the marine environment, so that the "plastic plague" does not spread, and the white earth is clean again, each of us is working hard to do so.
Bibliography:
[1]https://www.sciencedirect.com/science/article/pii/S0048969717308148?via%3Dihub
[2]http://www.stdaily.com/index/kejixinwen/202206/0f5ac84114734c59b3e594a6d599f0b7.shtml·https://tv.cctv.com/2022/06/10/VIDEznP0t1fR8tH6ebEYlXQt220610.shtml
[3]《Environmental Sciences and Technology》杂志