When a nuclear accident happens, as was the case with the accident with cesium-137 in Goiânia, many news use the terms “radioactive contamination” and “irradiation”. But are these terms used correctly? Do you know the difference between radioactive contamination and irradiation?
THE Radioactive contamination happens when a radioactive material is absorbed by an individual's body.. Any type of contamination occurs when there is a unwanted presence of a material in a place where it should not be.
In the accident with cesium-137, for example, Leide das Neves, a girl of just six years old, caught the “dust bright blue”, which was actually cesium-137 chloride, he played with it and then went for a snack without washing the hands. Thus, it was contaminated because it absorbed the radioactive material both through the skin (through the skin) and by ingesting it in small amounts.
Among the people examined in this accident in Goiânia, four, who ended up dying and were among the 14 people removed to the Marcílio Dias Naval Hospital, in Rio de Janeiro, had external and/or internal contamination, that is, they had direct contact with the radioactive material, and also lesions characteristic of the exposure of part of the body or body whole. Leide das Neves was the first of these fatal victims.
When a person experiences radioactive contamination, they also become a threat to other people, because the radioactive material that is present in it continues to emit radiation, which can contaminate others. This shows us that every infected person was also irradiated.
On the other hand, irradiation is the characteristic energy emitted by a radioactive source. It occurs when there is an exposure of one's material or body to radiation emitted by the radioactive element. This can happen without the person coming into direct contact with the radioactive material, that is, keeping a distance. Thus, not every person who has been irradiated has also been infected.
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Illustration of difference between contamination and irradiation
Thus, a person who has undergone radiation does not become a source of radioactivity, thus not posing a danger to other people.
As explained in the text Radioactivity in food and agriculture, irradiated foods are exposed to a radiation source, such as cobalt-60 or cesium-137, for a controlled time and without any direct contact. In this way, its deterioration process is slowed down, but the food does not become a source of contamination, we can touch it, handle it and eat it without fear. But the person who got close to a radioactive material and was irradiated suffers the consequences of that ionizing radiation.
Since alpha radiation cannot penetrate human skin, it does not harm a person who has only been irradiated. However, beta and gamma radiation have high penetration power and can cause serious and even irreparable damage. In the case of beta radiation, it can cross the skin up to 2 cm and cause problems such as skin cancer and eye damage. Gamma radiation has the greatest penetration power, reaching up to 25 cm of wood or 15 cm of steel. It is only held by 5-cm lead slabs or thick concrete walls.
To cite an example, in Enem 2012, the following question fell:
Question 84 of Enem 2012 - blue notebook
The correct alternative is the letter “a”. The decision taken by the airline was wrong because, as we have seen in this text, a medical material sterilized by irradiation does not become radioactive.
By Jennifer Fogaça
Graduated in Chemistry
Would you like to reference this text in a school or academic work? Look:
FOGAÇA, Jennifer Rocha Vargas. "Difference between radioactive contamination and irradiation"; Brazil School. Available in: https://brasilescola.uol.com.br/quimica/diferenca-entre-contaminacao-radioativa-irradiacao.htm. Accessed on June 27, 2021.
