170 trillion plastic particles are afloat in the oceans: What a new study says about microplastics

Although it’s difficult to pinpoint the exact number, the vast majority of these plastic particles are microplastics, which are particularly harmful to the oceans. They don’t readily break down into harmless molecules, and marine organisms mistake plastic for food.

A new study estimates that an estimated 170 trillion plastic particles weighing about 2 million metric tons are currently afloat in the oceans worldwide. The study added that if no urgent action is taken, this number could nearly triple by 2040.

Published recently in the journal PLoS ONE, the peer-reviewed study, ‘A growing plastic smog, now estimated to be over 170 trillion plastic particles afloat in the world’s oceans — Urgent solutions required’, has been done by Lisa M Erdle and Marcus Eriksen of the 5 Gyres Institute (California), Win Cowger of Moore Institute for Plastic Pollution Research (California), Patricia Villarrubia-Gómez of Stockholm Resilience Centre (Sweden) and six other researchers.

“The situation is much worse than expected. In 2014, it was estimated that there were 5 trillion plastic particles in the ocean. Less than ten years later, we’re up at 170 trillion,” Villarrubia-Gómez said in a statement.

Speaking to The Indian Express, Cowger explained that although it’s difficult to point out the exact number, the vast majority of plastic particles found on the ocean’s surface are microplastics—tiny plastic particles that measure less than 5mm in diameter.

Microplastics are particularly harmful to the oceans as they don’t readily break down into harmless molecules. They adversely affect the health of marine organisms that mistake plastic for food. Moreover, these particles can trigger loss of biodiversity and threaten ecosystem balance.

What are the findings of the new study?

The researchers analysed surface-level plastic pollution data from nearly 12,000 ocean stations in six major marine regions from 1979 to 2019. Then, they combined this with data they collected during their expeditions. Finally, using computer modelling, the researchers created a global time series to estimate how much microplastic is currently in the oceans and how its concentration has changed over the years.

They found that from 1990 to 2005, the number of plastic particles more or less fluctuated. One of the reasons for this could be the effective implementation of essential policy measures at the time. “In the 1980s and 90s, some international policies, like MARPOL Annex 5, enforced laws against dumping trash at sea. They were powerful laws that were enforceable and were preventative,” Erdle told

However, things went downhill soon after as the world began producing much more plastic than ever before. “Since 2005, we have produced more than 5,000,000 tons of new plastic into the world, and with more plastic, there is more pollution,” said Erdle, adding that the older rules weren’t enough to thwart the rising plastic pollution.

Therefore, as the study pointed out, the concentration of plastic particles, including microplastics, in the ocean has skyrocketed since the mid-2000s and continues to increase, researchers further mentioned that if the world fails to take drastic action about the issue, there will be a 2.6-fold increase in plastic flowing into aquatic environments by 2040.

“So far this century, the policies trying to address plastic pollution have been weak, and they have been voluntary and focused on recycling and cleanup. They don’t work very effectively. That’s why in our paper we advocate for a strong UN treaty on plastic pollution that is enforceable, not voluntary, and preventative, not focused on Clean up and recycling.,” Erdle said.

How do microplastics impact the oceans and marine life?

Several recent studies have detected microplastics in marine organisms, from phytoplankton to whales and dolphins, which might prove hazardous for them. According to Eriksen, one of the new paper's co-authors, ingesting such particles can cause “mechanical problems, such as lacerations and blockages to internal systems.”

He added, “Ingested plastics can cause chemical problems by leaching absorb chemicals into organisms. We know that microplastics absorb many hydrophobic compounds, like DDT, PCBs and other industrial chemicals, and evidence shows they can be released when ingested.”

Not only this, but microplastics can also disrupt the carbon cycle of the oceans. Typically, phytoplankton absorb carbon and are eaten by zooplankton, who excrete the carbon as faecal pellets that sink to the sea floor. Once these carbon-containing pellets reach there, “the carbon can be remineralized into rocks — preventing it from escaping back into the atmosphere,” reported Grist magazine.

But if zooplanktons consume microplastics, their faecal pellets sink at a much slower rate, which means they are more likely to break apart or be eaten by other animals — “making it less likely that the carbon will reach the seafloor and become permanently sequestered”, the report added.

What can be done to limit plastic pollution in oceans?

Researchers of the latest study suggested an urgent need to implement a global resolution to limit the production of single-use, throwaway plastic.

“We need cities to manage their waste so it does not leave their territory. We need to reduce the amount of chemical additives in new plastic products. If we talk about recycling, there have to be requirements that recycled plastic be used in new products. The industries that make plastic like to talk about how technically we can recycle all of it. But they don’t like to commit to buying recycled plastic, therefore recycling fails. They must legally be required to put at least 75% recycled plastic in any new product,” Erdle said.

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