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“There is no free love in concrete houses,” sang Martyna Jakubowicz. Today it is not so bad with love, but in most of our apartments there is also carcinogenic radon, which penetrates through poorly secured foundations. How can we protect ourselves against it? Zuzanna Opolska from Medonet.p talks with dr hab. Krzysztof Kozak * from the Institute of Nuclear Physics of the Polish Academy of Sciences in Krakow.
Zuzanna Opolska, Medonet: Doctor, how carcinogenic is radon, do we really have anything to be afraid of?
Dr hab. Krzysztof Kozak: According to the reports of the World Health Organization, it is the main carcinogenic factor that non-smokers are at risk of, and the second one is for tobacco smokers (carcinogenic cigarette smoke comes first – ed.). them through a poorly secured foundation. Most of us have heard that radon is a carcinogen, but we don’t know where it occurs or how it enters buildings. Or what is most important – how to minimize the risk associated with its presence.
Let’s start from the beginning, i.e. from the radon itself and what is so carcinogenic in it.
Radon, as a gas, remains in our lungs for a relatively short time, but constantly. It is therefore a situation of constant exposure to its effects. Radon breaks down very quickly in 3,8 days. And the derivatives of this decay include radioactive isotopes: polonium, bismuth and lead. By combining with airborne aerosols, they build up in the lungs and can pose a risk of developing cancer.
How big is this risk?
With an increase in radon concentration in the home by 100 Bq / m3, it rises from 11 to 13 percent, so this factor should not be underestimated! According to the WHO, 3 to 14 percent of lung cancers in the world are caused by radon.
Is the only type of cancer that can cause lung cancer?
No, not just this one. The World Health Organization talks about radon as a factor influencing the development of cancers of the entire respiratory system, i.e. larynx, trachea, mouth.
Smokers are more exposed to the effects of radon. Were there smokers too?
Yes, the risk of lung cancer, especially among smokers, is particularly high. This is a synergistic effect – the combination of both factors gives a greater probability of getting sick than the sum of the probabilities of both factors occurring separately.
For whom, apart from smokers, is radon especially dangerous – children, women …?
For children, first of all, because they have more years of life ahead of them, and therefore longer exposure to radon, also due to their height – they are closer to the main source of radon radiation, i.e. the ground. As for gender, there is no research on who, women or men, are at higher risk.
So we must be equally afraid.
I would not want to scare anyone, because we are talking about the risk of cancer. And this does not mean that we will definitely get cancer while staying in high-concentration rooms.
There are stochastic (random) and deterministic factors. Studies in which radon was a deterministic factor of lung cancer concerned populations particularly exposed to its high concentrations (in the order of thousands of Bq / m3) – uranium miners. However, no increased risk was found among mine miners in salt, potassium, nickel or copper mines.
As part of the project “Radon and its impact on the health of children and staff in kindergartens in the Visegrad countries”, the concentration of radon in Krakow facilities was investigated. How did our kindergartens compare to Hungarian or Slovak ones?
This project was coordinated by Dr. Jadwiga Mazur from our laboratory. Due to the limited financial resources at our disposal, we selected only 8 kindergartens in Krakow for the study, so it is difficult to talk about the situation in Polish kindergartens. In these eight, radon concentrations were lower than 300 Bq / m3. By the way, I would like to thank the directors and employees of these kindergartens and the Department of Education of the City Hall in Krakow for their help in the project.
How is it in the Czech Republic, Slovakia and Hungary?
The measurement campaign in the local kindergartens is carried out on a much larger scale within the framework of other programs. The highest concentrations were observed in kindergartens in Slovakia and amounted to over 1000 Bq / m3.
What radon concentrations are safe for us?
No threshold “safe” concentration of radon has been defined below which there is no increase in the risk of developing respiratory malignancies. Even very low concentrations of this gas increase the risk of morbidity. The initial tumor induction can even occur as a result of single cell damage. We are talking about probability, so even a single alpha particle from the decay of one radon atom can cause an unwanted mutation.
However, the regulations define some contractual safety standards?
We have recommendations from the World Health Organization and the European Union. Directive of the Council of the European Union (2013/59 / EURATOM), obliging member states to introduce national regulations by February 2018, establishes a reference (reference) level of the average annual radon concentration not higher than 300 Bq / m3 with the possibility of changing this value, justified by national conditions . It is very important to understand the term “reference level” correctly.
Exactly, that is …?
If the concentration of radon in your apartment is, for example, 600 Bq / m3, it does not mean that you should be escorted by the municipal police and the building should be leveled.
However, in this case, measures should be taken to reduce the concentration of radon. In short, a reference level is a recommended maximum level that is acceptable, not a limit value that must absolutely not be exceeded. Of course, it would be best if the average annual radon concentration in residential and public buildings did not exceed 100 Bq / m3. This is a recommendation from the World Health Organization (WHO).
Where in Poland are the concentrations of radon the highest? In the Sudetes?
Yes, and it is closely related to geology. Radon is formed by the decay of radium (Ra-226), which in turn is one of the decay products of uranium (U-238). If there are significant amounts of radium or uranium in the ground, it is suspected that the concentration of radon in the living air may be higher. There were uranium mines in the Sudetes, which were closed in 1972. The first uranium tunnels were dug by the Soviet army in the 50s in the Western Tatras in the Białego Valley.
So the inhabitants of the mountains are most at risk?
I would like to emphasize that the radon problem is primarily a local problem. If we have two building plots located next to each other, then the radon risk index on one of them may be low, and on the other – high. The factor which determines the amount of radon emission is the course of tectonic zones. If a fault zone runs through a given area, i.e. a plane cutting vertically or obliquely rock layers, the rocks within it are loosened and crushed, and this is the ideal path for gas migration. A good example is Wola Justowska in Kraków, located in an area with tectonic faults, where radon concentrations in the ground air are very high. Another issue is soil permeability. If, for example, we have clay under the house, it is a membrane that does not allow any gas to pass through. But sand or gravel do not provide such protection anymore. In many European countries, the radon index of the building plot is determined before building a house. The concentration of radon in the ground air and soil permeability are measured. And the function that intertwines these two values tells us whether the plot is safe or not.
How does radon get into buildings?
From the ground, through all leaks. The pressure difference means that it is sucked into the interior through the gaps in the foundations or at the sewage pipes. Unfortunately, the awareness of Poles leaves much to be desired. And without knowing the problem, we don’t know how to protect ourselves. When building a house, the key issue is to ensure that the foundation is airtight and that all connections are sealed. Cracks in walls or foundations are natural routes for this gas to migrate. If the radon index of the building plot is high, we can buy special anti-radon films available on the market. It is also important to select and control building materials in terms of the concentration of radioactive elements. It is worth adding that the control of natural radioactive elements in raw materials and building materials is already regulated by our law (Journal of Laws No. 4, item 29 of 2.01.2007 January XNUMX).
And if we bought a finished house where the radon concentration is high, what can we do?
There are many reduction methods and, contrary to appearances, they are not expensive. A good solution is adequate and regular ventilation of the rooms.
It has to be “intelligent ventilation”, i.e. either the ground floor or the basement is ventilated. Cracks in foundations and walls should be sealed, we can also use supply and exhaust ventilation.
In some countries, it is necessary to present a special radiation certificate before obtaining a building permit. In Poland, no one requires such a certificate, why?
For example, Norway and the Czech Republic have such regulations. Perhaps the Polish law will also include relevant provisions in connection with the implementation of the Directive of the Council of the European Union (2013/59 / EURATOM). There are important proposals in the draft act “Atomic Law”. One of the regulations states that the buyer or tenant of a building, premises or room intended for people to stay has the right to demand from the seller or the lessor information about the average annual radon concentration. The second one obliges the investor to determine the radon index before applying for a building permit for a building intended for the collective stay of patients, children and adolescents. The next step is to establish the so-called radon plan for Poland. What is needed is recognition of the “radon situation”, collection of archival data, screening measurements and an information campaign in the municipalities, including training for local authorities, residents, construction companies and developers.
How can we measure the radon concentration at home?
Measurements are simple and not bothersome. We have active methods, which are primarily used to study the migration paths of radon, and passive methods, which show us its average annual concentration. For this purpose, a special detector is used. It is a small container in which a special foil is placed. The detector is left in the apartment for about 1 month. After the measurement, the detector is sent back to the laboratory for “reading”. The particles emitted by radon cause radiation damage to this film. After chemical treatment, we can see these damage under a microscope in the form of small holes – traces. The more of these traces on the detector surface, the greater the concentration of radon in the tested room. Measurements should be carried out by accredited laboratories, which guarantees the correctness of the results.
* Dr. Krzysztof Kozak, physicist, employee of the Institute of Nuclear Physics Henryk Niewodniczański of the Polish Academy of Sciences in Krakow (IFJ PAN), head of the Laboratory of Radiometric Expertise of the IFJ PAN.
Co-author of over 170 publications in the field of: gamma radiation spectrometry, artificial and natural radioactivity, incl. radon measurements.
Winner of the Krakow City of Science and Technology Award (1998, team award), decorated with the Silver Cross of Merit for scientific achievements by the President of the Republic of Poland (2007).
He is a member of the Executive Committee of the European Radon Association and the Council of the Radon Center – Non-Governmental International Scientific Network, T.a Physical Society; The Polish Society for Radiation Research, the Team of Experts for Emergency Situations at the Mayor of the City of Krakow, the Team for the development of the long-term program “Atomic science in the service of knowledge and society”.