Surrounded by microplastics: The tiny pollution we drink, eat and breathe

Plastic is a material invented by humans that has gone from not existing at all to spreading uncontrollably across the planet. Micro- and nanoplastics have been detected in the oceans, in the air, in rain, in our food, in the water we drink and even in our cells. However, if there are still questions about this form of pollution and its effects, this is largely due to the great complexity of carrying out research on such a small scale, with such tiny contaminants.

The water we drink is an example of this challenge. What contains more microplastics: tap water or water from a plastic bottle?

A study published by the Enviroplanet research network found 89 times more microplastics (nanograms per liter) in bottled water than in tap water in Spanish cities. However, another investigation carried out this year by the Institute of Environmental Diagnosis and Water Studies (IDAEA-CSIC), found the opposite: more microplastics in tap water than in bottled water.

This disparity in results is largely due to the different methods used to detect micro- and nanoplastics that cover different sizes, since there is no approved technique that is followed by all researchers.

This is one of the most widely used methods, but there are other systems where researchers do not have to count tiny particles under the microscope. In the IDAEA-CSIC research, the scientists separated the micro- and nanoplastics with ultrafiltration equipment, dissolved them in toluene and passed the solution through a mass spectrometer. This way they found what types of polymers were in the water and in what amount.

A new technique developed by researchers at Columbia University to detect increasingly smaller plastic fragments found on average about 100,000 particles (most of them nano) in a liter of water from a plastic bottle, an amount much higher than previous estimates.

Regardless of the technique used, it is clear that we are drinking plastic. Although the number of microparticles is very high, the mass concentration of what we ingest is usually quite low. As Enviroplanet scientist Roberto Rosal explains, even taking the highest measurement of 1,600 nanograms per liter from these two recent investigations in Spain, to ingest one gram of plastic a person would need to drink 625,000 liters of this water. And if the recommendation to drink three liters of water a day is followed, it would take a person more than 570 years to achieve this.

But care needs to be taken. This may seem like an insignificant amount, but here, again, the problem is just how small the microplastic is. As Marinella Farré, a researcher at the IDAEA-CSIC, points out, “the smaller it is, the more it scares me.” “If it is too big, I will swallow it, and it will probably be in the intestine for a while, but it will eventually come out. But if it is small or small enough, it can pass through the tissues and then be absorbed into the body and stay there.”

The fact that we are drinking, eating and breathing micro- and nanoplastics can affect our health in two ways: first due to presence of foreign particles in the body, and second, as a result of the effects of the chemical additives used to make these materials.

Micro- and nanoplastics have been found throughout the human body: in blood, the placenta, breast milk, inside cells... Recently, new research warned that this plastic had even been found in the testicles. Although there are still many questions about how this affects health, a study on the carotid artery is one of the first to link this contamination with human diseases. More experiments are needed to confirm these conclusions, since these investigations are complicated by the risk of contamination from the tiny particles in the laboratory itself.

As Emma Calikanzaros, an ISGlobal researcher who works with microplastics, points out, “with this type of small particles, some figures may seem insignificant, but the problem is that we are exposed to them everywhere, every day.” What’s more, she explains that, “apart from all types of plastics and additives, we do not know the effects that the mixture of all of them has on the body, the cocktail effect of these substances.”

Microplastics everywhere

While most people talk about microplastic pollution in the oceans, we are most exposed to them in our own homes. In the last century, houses have been filled with objects and materials made with these polymers. They are everywhere: in food packaging, in electronic equipment, in synthetic textiles, in cosmetics...

Washing clothes is one of the main sources of microplastics, since washing machines release a large amount of microfilaments down the drain. But the wear and tear of the textile itself also releases fragments into homes. According to Nicolás Olea, a professor of Radiology and Physical Medicine at the University of Granada, house dust contains mainly plastic microfilaments from textiles, especially polyester and, to a lesser extent, polyamide (nylon). “Nowadays the majority of textiles are also plastic, if we talk about food packaging, I explain that clothing is human packaging, because we are stuffed in plastic,” says Olea.

In addition to textiles, electronic equipment and cosmetics, Professor Olea also points to the odorants used in homes and consumer products that now contain plastic, such as tea bags. He also warns about an item that became widely used during the Covid-19 pandemic: face masks. “One of the most striking buildups of plastic in the body is in the lung tissue and polypropylene, a material linked to masks, is found in large quantities,” he says. “This is a mess, isn’t it?”

Although it is difficult to find scientific data on this type of pollution in homes — due to its magnitude and the size of the particles —, Enviroplanet researchers have studied microplastics spread across a country. In Spain, they observed how wastewater from homes and industries continues to come out of treatment plants with a large amount of plastic microparticles, which end up in rivers or agricultural fields (through sludge). Using airplanes, the researchers also found concentrations equivalent to a trillion microplastics in the sky over Madrid, at an altitude of between 1,500 and 2,000 meters.

In this way, transported by the water of rivers and oceans, as well as by wind, atmospheric currents and raindrops, plastic microparticles have been spreading all over the planet. “Plastic is a material without which we cannot live in our industrial society, it is a very useful material that we need,” says Rosal, of the scientific platform Enviroplanet. “We must manage this material so that the waste does not continue to be scattered without control,” he adds, warning that with this kind of pollution, “it is easy to fall into alarmism.”

The plastic tide that washed up on Spain’s northwestern coast of Galicia in January — after thousands of plastic pellets were dumped in the sea — highlighted the magnitude of this pollution. It made visible a problem that tends to go unnoticed, as the pollution is made up of tiny particles invisible to the human eye. But the pellets that reach our oceans are just a miniscule part of the problem.

International negotiations on the first global treaty against plastic pollution are currently underway. The goal is to have a text ready by the end of 2024. Meanwhile, plastic production continues to run rampant across the world, while scientific research is stepping up its efforts to learn more about the impact of micro- and nanoplastics.

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