Plastics and microplastics are all around us. They appeared in the 1950s and have become part of our everyday reality. We build with plastic, wear it, transport in it, and wrap our food in it. However, more and more questions are arising about this material with many practical properties. Microplastics are found practically everywhere; in water, soil, and air. But how do microplastics actually interact with the human body? What impact do they have on our environment and our health? Is it true that they penetrate places like the brain or placenta? And if so, what does that actually mean? Just like elsewhere in the world, these and many other questions related to plastics occupy the minds of many scientists in the Czech Republic, including one directly at the RECETOX center.
Ondřej Adamovský is an environmental toxicologist who has long been involved in the issue of plastics and microplastics at the RECETOX center. Although his research scope is broader, he is currently focusing primarily on developing new methods within the CEITEC VUT, University of Ljubljana, and Technical University of Vienna consortium to unequivocally prove the presence of microplastics in the human body and organisms. Despite the hundreds of articles published annually warning about microplastics, a serious method to truly prove their presence in the human body is still lacking.
“Scientific articles that are now widely appearing and reporting that microplastics have been found in lungs, placenta, brain, or penises raise the question of how they could have gotten there. Unlike chemical substances, which are soluble, microplastics are solid particles, and those above a certain size cannot pass through biological barriers and move within the body. From this perspective, our current project is very beneficial because the newly developed methods for detecting microplastics will provide very precise information about what sizes and types of microplastics are capable of migrating within the human body,” explains Ondřej Adamovský.
The ability of particles to migrate through tissues raises the most questions. While the conclusions of scientific articles pointing out the findings of microplastics in the lungs, where microplastics can get, for example, by inhalation from the surrounding environment, are quite logical, the findings of microplastics in internal organs (brain, penises, or placentas) require a great deal of scientific scrutiny.
“These studies are scientifically questionable and need to be read in detail. Specifically, in a recent, media-friendly study that found microplastics in penis biopsies, it is stated that microplastics in the tissue can be one hundred to five hundred micrometers in size, which is basically the size of a grain of sand. The claim that solid particles of this size could pass through the digestive tract, overcome biological barriers into the blood, and accumulate somewhere is absolutely excluded and scientifically questionable,” says Adamovský.
How is this possible then? The most likely explanation for the presence of microplastics in the samples is secondary contamination. Given that microplastics are all around us, they most likely got into the samples simply during handling. For example, the mentioned research on the presence of microplastics in various human organs takes place in several locations, from the operating room, the sample processing site, to the place where the analyses are performed. Even though these are always clean rooms, microplastics are ubiquitous, and the fact that microplastics are also part of dust contributes to contamination.
“In the case of the study with placentas, the mechanism of unintended contamination may be similar. The placenta is delivered, then taken somewhere, samples are cut from it, and if proper procedural steps and controls are not in place, it is impossible to say that the plastic comes directly from the organ and did not get into the sample later,” explains Adamovský.
The new method that the scientist is now working on with a team of other researchers is instead based on the use of computer tomography, which works with intact tissues. Therefore, it is not necessary to disrupt or interfere with them in any way for their examination, thus minimizing the risk of secondary contamination. Based on in vivo models, scientists will look at what microplastics, what sizes, and in what places can be deposited in the organism. The larger vision is then to use human samples and analyze microplastics in tissues through biopsy. According to Adamovský, only then will we have truly indisputable proof that microplastics can move across tissues and subsequently accumulate in them.
“Another problem with articles and reports is that despite the enormous amount of histopathological observations made since the 1950s, doctors have not found microplastics anywhere. Ten, twenty, fifty, or one hundred micrometers, these are large plastics visible under a microscope. However, no one has ever recorded them during observations, which is strange. This fact suggests that the articles are not well done, and until someone provides a methodology, like the one we are currently working on, all other research is very easily questionable,” claims Adamovský.
Although it seems there is not much to worry about yet, monitoring the risks associated with microplastics is more than essential. If their presence in human tissues is indeed proven, it will be necessary to further investigate their effects on human health. The issue of plastics also has another dimension, which is their chemical composition.
“It can be said that microplastics as particles are still an open and researched topic, but plastic additives, i.e., the chemical substances contained in them, have been tested for a long time, and their risks are known. For example, the group of phthalates1, which we also studied here at RECETOX, was found to be so dangerous that they were globally banned in 2022,” adds Adamovský.
Fortunately, legislation in the context of microplastics is progressing. Over the past five years, the European Union has issued regulations banning the use of microplastics in cosmetic products or consumer products, which will help reduce their emissions into the environment2.
“Microplastics have already disappeared, for example, from shampoos, where they were added as exfoliants, and certain types of plastics were also used in mascaras or cosmetic fillers. Compared to the United States, this measure came later, but it is more thorough, as it will also apply to so-called leave-on cosmetics, such as sunscreens or cleansing facial gels, which is not the case in America,” explains Adamovský.
Even smaller particles, but an even bigger problem, are nanoplastics. These plastic particles are so small that no visual technique can capture them. Therefore, their study is challenging, and very little is known about nanoplastics so far.
“Detection methods are very poor, they basically do not exist. So far, we know that nanoplastics, unlike microplastics, can pass through biological barriers, but the question is what they can cause. There are initial studies showing that nanoplastics can induce pro-inflammatory states,” warns Adamovský.
The overarching root problem of microplastics and nanoplastics is, first and foremost, plastics themselves. As the name suggests, microplastics are formed during their degradation. In practice, these particles get into soils, for example, by the breakdown of protective plastic films used to protect agricultural areas against weeds or water evaporation. Another significant area where microplastics are released through degradation is food production and packaging.
“Ninety percent of all packaging materials are plastics. It doesn’t matter whether we take yogurt, meat, or vegetables, if they are in plastic packaging, microplastics will also be present in them. However, they do not only get into them from the packaging. The food production process almost always involves a phase where plastic is used, whether it is plastic pipes, containers, or another part of the production. Microplastics thus penetrate products primarily during production, and so we find them even in beverages in glass bottles, aluminum packaging, salt, oils, or honey. There is no large-scale production that can do without the use of plastic components,” describes Adamovský.
For plastics in their versatile use today, there is no sufficient alternative. However, there are ways to at least mitigate their impact. One proposed measure is the unification of the allowed composition of plastics. This would allow plastics to be returned to the economic cycle, i.e., recycled.
“Currently, each plastic is completely different and full of various additives. You can’t even combine two plastic cups from different brands; it’s an unidentifiable mix used only by specific manufacturers. This is why plastic packaging is recycled into building materials3, but this type of product is permanent and does not return to the circular economy,” explains Adamovský.
The Czech Republic is also looking for ways to improve the dire situation with plastics. A team of researchers, with whom Ondřej Adamovský is now seeking new methods for detecting microplastics, has commented on the Global Plastics Treaty for the Ministry of the Environment. This treaty should help with the current one-way flow of plastics that end up in waste without the possibility of recycling.
“Currently, mainly PET bottles are recycled because they have no additives; they are more or less the same. This is a big exception; most other plastics are usually burned. This treaty aims to ensure that the vast majority of plastics somehow return to circulation and become part of the circular economy. We can contribute to treaties related to plastics with our expertise, specifically an overview of the bioactivities of chemicals contained in plastics,” explains Adamovský.
What is currently missing at the level of political negotiations in the Czech Republic is a foundation or association that would create a counterbalance to the industry in discussions about national implementations. An example of such good practice could be the Food Packaging Forum.
“The Food Packaging Forum is an entity that the government can turn to for verifying information or consulting on planned measures. They are capable of gathering scientific evidence or data that is publicly available and drawing clear and substantiated conclusions from it. Global treaties are generally very broad, and their implementation is entirely up to the governments of individual states. This kind of support is currently missing in the Czech Republic, and that is a shame,” summarizes Adamovský.
[1] Phthalates were mainly used to soften polyvinyl chloride (PVC) plastic to make it suitable for use in a wide range of consumer items. These include vinyl flooring, food packaging, footwear, and clothing. Phthalates were also added to personal care products, including soaps, shampoos, hair sprays, perfumes, and nail polishes. They were found in soft plastic sports and recreational equipment, and some were also in the coating layers of medicinal products and dietary supplements, or in medical devices made of softened PVC.
[2] From October 17, 2023, Regulation (EU) 2023/2055 restricts the use of synthetic polymer microparticles, known as microplastics, in various products. Microplastics are defined as synthetic polymer particles smaller than 5 mm, which are organic, insoluble, and resistant to degradation. They are found in many everyday products, including cosmetics, cleaning agents, fertilizers, and even sports surfaces. The regulation includes transition periods for different products, with some bans taking effect immediately and others being gradually introduced over the next decade. For example, rinse-off products containing microplastics will be banned from October 2027, while some medical devices will have until October 2029.
[3] One of the most well-known forms of recycling is downcycling. It is a method of reusing materials, as a result of which the waste loses certain properties and is therefore less valuable than the original product.
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