With each passing year, the production of plastics worldwide increases. Some of this material ends up in the sea. If in 2005 there were 16 billion particles on the surface of the Earth’s oceans, equivalent to 220,000 tons, in 2019 these values reached 171 billion particles, or 2.3 million tons of plastic, according to estimates of an article published this Wednesday in the magazine PLOS ONE.
That is, there has been a more than tenfold increase in the number of plastic particles in just 15 years.
The new research compiled information from various databases on plastic particles from samples taken at 17,777 stations in six marine areas – North Atlantic and Pacific Oceans, South Atlantic and Pacific Oceans, Indian Ocean and Mediterranean Sea – between 1979 and 2019. In the year 2005 marks a major turning point in the plastic pollution situation, when the amount of particles begins to clearly increase, according to the article.
“The amount of microplastic floating in the world’s oceans has been increasing rapidly since the beginning of the millennium,” Markus Eriksen, co-founder of the 5 Gyres Institute, in the United States, which studies the impact of litter, points out to PÚBLICO. in the oceans and is part of the “global movement against plastic pollution,” it says web page of the institution. In addition to the United States, the article also has the collaboration of researchers working at institutions in Australia, Chile, and Sweden.
In 2014, work done by the institute showed that there were 268,000 tons of plastic of all sizes floating in the ocean. At that time, part of the data was obtained during oceanographic missions carried out by the 5 Gyres Institute. Now, fieldwork done by the institute has also gone into plastic accounting, but the team only considered pieces of plastic with sizes between 53 and 505 micrometers.
“For many years, we dragged our nets on the surface of the ocean. We don’t have plastic data on the ocean floor or on the shores. Our focus is on plastic items it floats,” explains Markus Eriksen.
Markus’ team calls these types of small particles “plastic smog.” “We coined this term almost ten years ago. It made sense because most of the plastic in the ocean is microplastic, suspended above the five subtropical marine current systems [no Norte e no Sul do Atlântico, no Norte e no Sul do Pacífico e no Índico] as if it were a giant cloud and each particle carries its own toxicity,” the researcher tells us. “It’s like air pollution in big cities.”
Monitoring and assessments
Plastic in the environment and more specifically in the oceans is a source of many problems. On the one hand, it can be ingested by animals and enter food chains. On the other hand, apart from the fact that plastics are made up of different types of compounds, some of them harmful, this material can retain on its surface pollutants it has come into contact with that will contaminate marine waters.
In addition, the microplastics penetrate into terrestrial systems. Because they are so small, they even manage to penetrate the circulation, as has already been proven in analyzes done on human blood. But the health implications are far from being fully understood.
The results now achieved by Markus Eriksen and the rest of the team are yet another confirmation of what has been realized regarding the dimension of this problem. And they show the importance of long-term monitoring of Earth’s systems. “These trends help us understand whether things are getting better or worse and create a baseline that allows us to assess how we will be in the future,” explains the scientist.
Although the information used in the article dates back to 1979, there are many gaps in the information. The samples were taken mainly from the North Atlantic and Pacific oceans. Only from 1990 onwards are the data more consistent and truly global.
From the microplastics picked up by oceanographic expeditions carried out over the decades, the researchers deduced with the help of mathematics the total number of microplastics present on the surface of the oceans each year. Therefore, what emerged were estimates.
For example, for the year 2010, the team calculated a minimum number of 56 billion particles and a maximum of 70 billion plastic particles, equivalent to 760,000 and 960,000 tons respectively. That is, for that year the average estimate is that there were 63 billion plastic particles floating in the ocean, which equates to 860,000 tons of plastic.
Despite the gaps in sampling and despite the margin of error that may exist in any estimate, the information obtained allowed the authors to safely determine two moments in the plastic state. From 1990 to 2005 there is no specific trend in the development of the amount of plastic, but from 2005 to now, the amount of plastic has increased.
One of the reasons for this sudden increase may be related to the increase in the production of plastics, which has accumulated. “Older macroplastic that washes up or gets trapped on shores and rivers continues to degrade and break down, contributing to the abundance of microplastics,” the article states.
But there is another possibility. “International policies to limit pollution were strong in the 1980s and 1990s,” says Markus Eriksen. But from that moment on, the situation reverses, the researcher claims. “We see a sharp increase in plastic pollution when international policies have become weak. Because they are not mandatory, they are voluntary, which is a problem because countries do not comply with the agreements,” says Markus Eriksen.
If these policies are not changed, the amount of plastic entering the oceans could increase 2.6 times between 2016 and 2040, according to an article published in Science reported in the new study.
“We need a very strong United Nations treaty against plastic pollution,” says the researcher. “The treaty should be legally binding and not voluntary, it should focus on limiting the production of single-use plastic products such as bags, straws, cups and bottles. One should not focus on recycling or cleaning up garbage.”