"There is not a single scientific proof of the harmful effects of plastic on the human body today"

The topic of plastics has been in the media lately, often in a negative context. However, this news is not always presented with proper commentary by scientists. Should we be afraid of microplastics in the human brain? Which studies should be trusted? Can and should we give up the use of plastic in everyday life? Head of the Department of General Hygiene, Director of the Erisman Institute of Public Health. F. F. Erisman Institute of Public Health of Sechenov University, Doctor of Medical Sciences, Professor Oleg Mitrokhin answered these and other questions to Izvestia.

- Recently, the media has been publishing a lot of materials about the alleged dangers of microplastics: it is found in tea bags, or in Antarctica, or in human brains in general. How serious is the problem in reality, and is there a problem at all?

- I follow very closely the studies that are published on this subject both in Russia and in the world. And I can responsibly state that to date there is not a single scientific work that would unequivocally prove the harmful effects of plastic on the human body. All the rest are hypotheses and reasoning: "possible harmful effect...", "probable adverse effect...". Yes, microplastics do occur in various organs and tissues. Because of its size, it penetrates into the blood and lymph, but it is safely excreted from there - and this is a scientifically proven fact.

I would like to note that an international legally significant treaty is being prepared to reduce environmental pollution by plastic, including in the marine environment. And there is a clause in it, which says that it is necessary to conduct further research in this direction, to exchange information so that advanced technologies, methods and techniques for studying the impact of plastic were standardized and used equally throughout the world. This is very good, I fully support it and I think that in the coming years scientific work in this direction will be intensively developed.

- Not so long ago the media reported that American scientists, studying the content of microplastic in the tissues of deceased people, found a particularly high content of it in the brain. Have you read this study? Can you comment on it?

- Yes, of course, I have perused these materials and here is what I would like to point out. The first thing that stands out is that there is no single methodology for determining nanoplastic in organs and tissues. It is a matter of fact that in this study the samples of materials were stored in plastic containers, plastic pipettes, plastic test tubes and beakers were used. So it is possible that what the scientists found in the brain tissue is a consequence of the use of plastic in scientific research.

The second thing I noticed was the small number of samples analyzed. Brain tissue samples from only 12 cases with dementia were analyzed and additionally received 28 more brain samples from other repositories. It is not very correct to build any mathematical dependencies and regressions based on such a limited number of organs and tissues studied.

Third, this study specifies the age, sex, and race composition of the deceased - that is, only three components. We have no information about where they worked, what they did for a living, and we know nothing about their dietary habits. Therefore, this set of three components also raises certain doubts about the results. And it is not very correct to draw unambiguous conclusions that the plastic content in the brain has increased by 50%.

Besides, if you noticed, the American researchers themselves are very cautious about their conclusions in this article, mentioning that there is a balance between the intake, content and excretion of plastic from the body. We all inhale a huge amount of different microparticles on a daily basis. For example, the same suspended solids found in atmospheric air. But nothing happens to them - they are simply excreted from the body and that's it. Therefore, I would be very cautious about the results of this article.

- Nevertheless, the public continues to be persuaded of the need to reject plastic. From a scientist's point of view, is the rejection of plastic really necessary?

- It is unlikely that most of us will suddenly decide to go back to tin packaging or glassware. We all live surrounded by plastic today, and all our food products are usually packaged in plastic, even water. And thanks to this packaging, food products are preserved longer. Food storage conditions and regulations should be followed. One should just do research and use those types of plastics that do not cause any concerns.

Plastic is present inside us, in the atmosphere and in the water - for example, it is found in our seas of the Arctic Ocean. But its content there is negligible - from a few dozen to a few hundred particles per 1 cubic meter of water.

- Are there any standards for the permissible amount of microplastics in the air, water, human body? How large is its amount in the atmosphere compared to other substances?

- Each of the chemical substances that are contained in the atmosphere, in the air of the working zone, has a standard - the maximum permissible concentration, exceeding which may cause some pathological changes in the body. There are no such standards for plastics and microplastics. The main task of scientists now is to systematize all received data on the content of microplastic and to derive unified standards of research and regulations. And when we will have unified standards and unified methodological approaches to the study of plastic pollution in air, water and soil, then we will have correct research on its impact on humans and nature.