Barely visible to the eye (the larger ones, that is), microplastics are found in the sea, in rivers and lakes, but also in the ice at the poles and in the most distant soils on the planet. Their size makes them so bioavailable that they are confused with marine plankton, thus entering the food chain at the top of which are the great predators, above all, humans. These have been eating, drinking and even breathing plastic for decades. Only 20 years ago, a group of scientists introduced the term microplastics for the first time. Now, these same researchers publish a review, today Thursday in the journal Science, with what has been discovered in this time. Their conclusion is that the accumulation of data on its high presence in the environment and its dangers is such that global action is required to reduce them.
Plastic has not been the basis of the infrastructure of human societies for that long. Researched and synthesized between the end of the 19th and 20th centuries, its mass production did not begin until 1950. A decade later, first fishermen and then scientists warned of the presence of plastic waste in the oceans. By the end of the 1970s, there were already dozens of studies on the accumulation of smaller pieces mixed in with plankton in the North Sea, the Sargasso Sea, the Caribbean, the South Atlantic… But it was not until 2004 that people began to talk about microplastics, when the journal Science published a short article in which its authors They mentioned the term for the first timeBy then, plastic had become essential to human civilization.
Plymouth University professor Richard Thompson was the first author of that text that sought to explain the inconsistency between the figures of plastic produced and that counted in the sea, finding the key, the presence of countless pieces that are increasingly smaller. “After 20 years of research, there is clear evidence of the harmful effects of microplastic pollution on a global scale,” says Thompson, who signs a new work, also in ScienceThe work is a review of what science, with more than 7,000 published studies, has learned about these tiny human creations. The first thing is their omnipresence. They were first detected in the sea, but they are also in the atmosphere. Research into their presence in soil is more recent, but according to this new review, the concentration in the seas could even triple. Overall, the amount is expected to more than double by 2040.
“There are still uncertainties, but over the 20 years since our first study, the amount of plastic in our oceans has increased by around 50%, which only further emphasises the urgent need to act,” Thompson said in a statement. In addition, plastics and microplastics have travelled very far from where they were used. Thus, plastic waste generated in Europe and North America ends up in the Arctic Circle, carried by the current. There, the action of time, solar radiation, waves… break it down into smaller pieces. It is now like microplastics that reach the mountains. In the Pyrenees, for example, you can find a concentration of these particles very similar to that found in Paris or in the industrious cities of China.
With a size of a few microns, microplastics are confused with the plankton that many species feed on or are accidentally ingested. However they arrive, their presence has already been documented inside specimens of more than 1,300 species of fish, birds and mammals. From the intestines of anchovies or sardines, to the stomachs of dolphins and seagulls, to the intestines of seagulls and other marine organisms. human testiclesThere is no definitive evidence that this presence has anything to do with the fact that human sperm quality has dropped by half over the last half century, but there is a temporal correlation. Only in recent years has progress been made in understanding the impact on the health of living beings. First there were experiments with mice, but now there are beginning to appear works that document how the presence of not only microplastics, but nanoplastics inside the human body increases the risk of suffering a heart attack or a stroke.
Thompson’s work warns about these nanoplastics, two or three orders of magnitude smaller than microplastics. As the University of Cadiz researcher Carmen Morales says, “the smaller they are, the more bioavailable.” But she quickly acknowledges that they are the great unknown, “we must refine the methodologies to detect them, to know what they are, where they come from,” she adds. If we start from the first classifications based on their origin, there are two major types of micro and now nano plastics. Primary and secondary. The former are those that were originally micro, such as the fibers that come off a sweater, the mini-spheres used in some cosmetics, the pellets or the tiny pieces that tires lose every time we brake too hard. But, according to the British professor’s review, the largest proportion corresponds to the latter, which come from the fragmentation of larger pieces of plastic until they become first micro and then nano. One of the conclusions of the study is that the rate at which more plastic is reaching the environment is much faster than the slow process by which its basic components are assimilated by the Earth through its mineralization.
The illusion of biodegradable plastic is also highlighted in the review carried out by Thompson. As Morales, who did not participate in this work, recalls, “in reality, many of the plastics that are advertised as biodegradable actually break up into smaller pieces.” And this has the paradoxical consequence that what is said to be more environmentally friendly is actually more harmful, as it accelerates the decomposition of the plastic, thus facilitating its ingestion or introduction into living beings. Since 2019, the European Commission has banned the manufacture and marketing of oxobiodegradable plastics, which rely on the action of oxygen to decompose them until they are removed from human sight, even if the plastic is still there.
Both Thompson and Morales are members of the Coalition of Scientists for an Effective Treaty on Plastics. They advise and also lobby States in favour of reducing our dependence on plastic. “Most measures place the responsibility on consumers, when the most effective ones should be higher up, at the beginning of the chain,” says Morales. In November, the United Nations will perhaps hold the definitive meeting to reach a binding global agreement. The Spanish researcher gives as an example the Montreal Treaty on CFCs, which in 1987 banned the manufacture of CFC gases, as they were the cause of the hole in the Ozone layer, with a transition phase. “It is not about eliminating plastics to zero, but rather analysing which are essential and which are not, and looking for alternatives,” concludes Morales. 30 years after that agreement, the hole in the ozone layer is beginning to recover.
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