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What are radioactive particles?

  1. May 30, 2015 #1
    I visited Chernobyl recently with a tourist company, having read that the radiation levels that I would be exposed to were okay for a limited amount of time.

    I learned on the trip however, that the greatest risk consisted in getting contaminated particles in your body. The guide took us around different places, inside buildings in Pripyat, for example the hospital where the firemen's hats were left. I washed my hands before eating in the canteen and I think that I did not touch my face inside the inner zone. But since the guide took us around at many places, it felt like it was impossible not to touch a wall or a plant here and there, even though I tried to avoid it. The scanner did not detect any radiation on my way out.

    What worries me, is that I might have gotten these particles inside my body, or that they are left on my jacket or something. Therefor I would want to understand more about these particles.

    - What is a contaminated particle? Can someone explain this? Can they be anywhere in the Chernobyl area? Or can they only be found in "hot spots"?

    - They have scanners on the way out from the zone - and it let me through. Do anyone know if these scanners are sensitive? Would they detect a small particle?

    - The guide touched the fireman's hat with the geiger counter, and later gave me the geiger counter - is it possible that contaminated particles got stuck on the counter and then on the guide's and my hand?

    - Is there any way for me now, to control or scan if I have any radioactive particles inside my body?

    I would be so grateful it if someone could answer me! I can't stop thinking about it!
  2. jcsd
  3. May 30, 2015 #2


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    Everything everywhere in the world is a bit radioactive, this is completely natural and has nothing to do with human activities. "Contaminated" means there is more radioactivity than normal.
    The radioactivity levels at Chernobyl outside the reactor complex are low today - as long as you don't live there for a long time it is fine. The radioactivity of a few dust particles is negligible.

    Did you fly to Chernobyl? You probably received much more ionizing radiation from the flight than from your stay there.
  4. May 30, 2015 #3


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    Also note that many of the foods that you eat have natural radioactivity. Anything high in potassium is especially so, such as bananas. In fact, I've seen units of radioactivity given in terms of number of bananas!

    Human being has evolved in a world surrounded by radioativity. We expect, on average, to receive about 360 mrem per year.

  5. May 31, 2015 #4
    Thank you so much for the answers!

    As I understand it, there are different kinds of radiation?

    I heard that I did not need to worry about the gamma-radiation, but that the danger lied in beta-particles. mfb, do you include these in the dust particles you mention?

    Thanks again!
  6. May 31, 2015 #5
    Alpha and beta particles have smaller range than that of gamma ray in the air. Therefore, as long as you eat something which is contamined with alpha or beta sources you will be fine. For instance, Rn-222 is a alpha source. When you breathe Radon gas, you will be exposed from inside and that is much more harmful than that when it is outside of the body.
  7. May 31, 2015 #6
    Thanks for the answer @oksuz_ ! Is it possible to breathe in alpha and beta particles? That is the real danger, I suppose? I ate at one moment in Chernobyl. But I washed my hands twice before, so that should be fine I suppose.

    @mfb I forgot to tag you. Thank you too for answering. What I wanted to ask you was whether you include alpha and beta particles in the statement that "the radioactivity of a few dust particles is negligible"?
  8. May 31, 2015 #7
    You can not eat or breath Alpha or Beta particles directly. As i said earlier, Radon-222 is a radiocative isotope which emits alpha particles when it gets decay. And these alpha particles are quite energetic, therefore they can create ions in your body and also they demage to genetic material of the cells which causes mutation.

    whatever you eat, i suppose, was carefully controlled before. if you followed instructions, it would be fine..

    There is a informative video for this. You may want to take a look at it.

  9. May 31, 2015 #8
    And thanks again @oksuz_ ! That makes me feel a bit safer.

    I visited the hospital in Pripyat, where they go in the documentary. We did not go down in the cellar though. One of the firemen's hats I saw however, it lied close to the entrance. A guide held the geiger counter to it, the counter touched the hat, and then later she gave the counter to me. When I realized that it had touched the hat, it made me scared. But do you think that would be a problem?

    We went into the hospital without any gas masks or anything, like the guy in the video wears. He says it is to avoid inhaling radioactive dust. So there must be something dangerous that I could have inhaled?

    I am sorry if I ask stupid questions! I have very little knowledge in physics.
  10. May 31, 2015 #9
    Remnant radiation in chernobyl, most probably, is coming from Cs-137 which is a gamma-ray source. And the gamma rays can penetrate in the air without loose much energy. Therefore, it does not matter whether you touch it or not, if you do not eat Cs-137. Since gamma rays loose very small amount of energy, whether you touch the hat or you stand 1 meter away from it, it woul not make much difference.

    Was your guide wearing a mask ?

    As it is said in the video, smoke has the most radioactivity. Do not worry about this so much, if you are not a smoker :)
  11. May 31, 2015 #10


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    That is no problem. Even taking the hat directly would have been fine.

    The guy in the video wears a mask because it looks interesting and gives more views.
  12. Jun 3, 2015 #11
    Thanks again!

    I am a bit confused though, from reading your answers, because it seems that you don't agree on whether I could breathe in these dangerous particles or not? Or whether it is dangerous or not?

    Do your views contradict each other? Or am I missing something? @mfb @oksuz_
  13. Jun 3, 2015 #12


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    Breathing in alpha- or beta- emmitting particles can cause damage, but with poisons, the amount is what matters. The main principle in radiation safety is known as the ALARA principle - As Low As Reasonably Achievable. Small amounts don't pose too much risk.

    ETA: And Oksuz was pointing out that you don't breathe in alpha or beta particles, you breathe in radioactive dust that emits alpha and beta particles.
  14. Jun 3, 2015 #13


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    Johnny_J, as with any other poison, it's all in the dose. If you were to breathe in dust from fallout after nuclear bomb burst, or stuff from the radioactive cloud the Chernobyl explosion released, or were caught in a dust storm shortly after the Trinity test near its site, then you'd have to worry (a lot).
    Swallowing, getting on your jacket, or breathing in some old dirt like you're worried you did is not going to do any harm. You're in no danger.

    Generally, getting radioactive stuff inside your body is worse than being exposed to it outside, because parts of the radiation such particles emit can be stopped by your clothes or your skin, whereas inside your body you're directly exposing your internal organs. Also, all of the radiation hits your body tissues since the particle is surrounded by it, whereas if you had one on your skin it's only half (the other half being emitted away from your body). Finally, stuff you get inside your body can get concentrated in one of your organs, such as thyroid or liver, and stay there for a while.

    But while it's worse it's not that much worse. It won't turn what is a rather quite safe tour into a health hazard.

    If you came here worried about your health because you ate that hat, rather than just stand near it and possibly maybe touch it a little, then it'd be a different story.
  15. Jun 3, 2015 #14


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    Yes, they are there to detect radiation above safe limits and are presumably sized/have the sensitivity required for it.
    Yes, but you'd know it since the geiger counter is detecting those particles. So when it was pulled away from the hat, if the counter didn't slow down, then maybe it took some particles with it. But I'm betting it did slow down...
  16. Jun 3, 2015 #15


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    Everything we eat and drink has a small amount of arsenic, mercury, beryllium and thousands of other chemicals that can kill you in large quantities - but their dose is so tiny that it does not harm us. The same applies to Chernobyl - as long as you don't visit the actual reactor.
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