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Aerial view of the Fukushima nuclear ruins on March 10, 2022
Photo: Maxar/DigitalGlobe/Getty Images
Parts of this text first appeared in 2011 in the context of the Fukushima nuclear accident. Due to the current situation, we are republishing it in an adapted form.
Russian soldiers are said to have driven tanks and armored vehicles through heavily radioactive terrain when they captured the Chernobyl nuclear ruins.
This is reported by power plant employees who claim to have been on site at the time of the attack on February 24, according to the Reuters news agency.
The soldiers wore no protective equipment and whirled up radioactive dust in the so-called Red Forest and probably inhaled it.
The information cannot be checked, as is so often the case in this war.
It is also unclear how much radioactivity the soldiers were exposed to if they actually drove through the heavily contaminated area.
But one thing is certain: the Red Forest is one of the most radioactively contaminated areas on earth.
It got its name from pine trees that died there after the Chernobyl nuclear accident and appeared in a reddish-brown color.
The forest was cleared after the supergau.
It is also clear that radioactive radiation can cause serious damage to health.
However, whether this actually happens depends to a large extent on the dose.
The damage is caused by ionizing radiation
People are exposed to radiation every day.
According to the Federal Office for Radiation Protection (BfS), the natural radiation exposure of a person in Germany is an average of 2.1 millisieverts per year.
Depending on where you live and your diet and lifestyle, the value varies between one and ten millisieverts.
For classification: With a short-term exposure of four sieverts, it is to be expected that half of the people affected will die.
This corresponds to 4000 millisieverts, i.e. two thousand times the annual average value in Germany.
Radioactive substances can enter the body through the air and through the skin.
Then they react with tissue and unleash their destructive power.
However, what causes problems for the body is not the radioactive particles themselves. It is the so-called ionizing radiation that they emit.
It knocks electrons out of molecules.
Chemically aggressive molecule residues remain.
Experts speak of radicals.
Gau in the body
In isolated cases, radicals do not cause any major damage, but the greater the ionizing radiation, the more radicals are formed.
Then a kind of meltdown can occur in the body itself: A dangerous chemical chain reaction begins in which the charged particles react with each other to form stable connections again.
However, since these chemical reactions are uncontrolled, they sometimes create compounds that make no sense in the cell.
For example, ionizing radiation can render important enzymes inoperable or destroy entire cell building blocks - if the damage is too great, the cell dies.
The genome is also susceptible to ionizing radiation.
If electrons are knocked out of the DNA molecule or if it comes into contact with radicals, this can lead to changes in the genetic information that are passed on to the daughter cells during the next cell division.
The body can deal with a lot of damage.
This is one of the reasons why the natural radioactive radiation in the ground or the atmosphere does not usually affect it directly.
The human organism has developed defense mechanisms to protect itself from these stresses.
It can repair DNA damage or specifically break down damaged structures in the cell.
Tomas Lindahl, Paul Modrich and Aziz Sancar received the Nobel Prize in Chemistry in 2015 for research into the body's own DNA repair mechanisms (read more about this here).
The limit of the body's own safety mechanisms
In the event of a catastrophe such as that in Chernobyl, however, these natural protective functions reach their limits.
Radiation sickness can occur with a short-term exposure of 0.25 Sievert or more.
That is 250 millisieverts, which is more than a hundred times the level of pollution that people in Germany are naturally exposed to on average every year.
Radiation sickness can manifest itself in many different ways.
How severe the symptoms are depends on which tissue is affected by the radiation and how badly.
In the case of mild radiation sickness, the first symptoms are headache, nausea and vomiting.
They appear a few minutes to hours after exposure to radiation.
Then they subside temporarily, only to return after a few days or even weeks as fever, malaise or skin changes and last for a few weeks.
People with such mild radiation sickness usually recover.
However, it can lead to a long-term weakness of the immune system, so that those affected have to fight infectious diseases more often.
The victims of the atomic bombings in Hiroshima and Nagasaki and the Chernobyl disaster show how agonizing acute radiation sickness can end in the worst case: hair loss, uncontrolled bleeding, destroyed bone marrow, coma, circulatory failure and other dramatic effects can lead to death.
The most well-known consequence is leukemia
Anyone who survives acute, strong radiation exposure is threatened with long-term consequences.
The best-known of all long-term effects is blood cancer, also known as leukemia.
The radionuclide strontium 90, which was also released in the Chernobyl accident, is stored in the bone tissue and thus increases the risk of cancer.
Experts like to call this substance bone-seeking because the body mistakes it for calcium and incorporates it into muscle and bone tissue during normal physiological processes.
Bone marrow is particularly sensitive because this is where the formation of new blood cells takes place.
When ionizing radiation comes into play, blood cell formation can get out of control and lead to leukemia.
At the same time, strontium 90 also increases the risk of bone cancer.
Plutonium 239 is also found in the exclusion zone around Chernobyl. It is one of the alpha emitters.
This means that the radiation from the plutonium only reaches a few centimeters in the air and is completely blocked by a piece of paper or cloth gloves, for example.
If alpha rays enter the body, they can still cause serious damage.
Iodine tablets protect - if they are taken correctly
Iodine 131 can also be released in nuclear accidents.
Due to its short half-life, however, it no longer plays a role in the Chernobyl region.
People can protect themselves from the consequences of iodine 131 with potassium iodide tablets.
The body stores iodine 131 in the thyroid gland in the same way as non-radioactive iodine 127. If, after taking the tablets, all iodine docking sites are occupied by the non-radioactive material, iodine 131 cannot settle in the thyroid gland, that is the idea.
After Russia's attack on Ukraine and fires at the site of the Chernobyl nuclear ruins, demand for iodine tablets grew in Germany.
However, the authorities gave the all-clear: radiological effects of the fire that has broken out in the meantime and has now been extinguished in Germany are not to be feared according to the status of the available information, reported the Federal Office for Radiation Protection (BfS).
In any case, iodine tablets only protect if you take them at the right time.
The iodine in the thyroid is continuously exchanged.
"If the pills are taken too late, radioactive iodine may already have accumulated in the thyroid gland," Martin Schulz, chairman of the Drug Commission of German Pharmacists, told SPIEGEL in early March.
"If the potassium iodide is taken too early, it may already have been excreted by the time the radioactive event occurs." So there's no point in swallowing the tablets as a precaution.
On the contrary: It can even be harmful to health, which is why experts urgently warn against it.
At the moment, one can only speculate as to what damage the soldiers in the Red Forest might have suffered.
There's a good chance it will stay that way forever.