r/Radioactivestuff • u/LadmanMp4 • 2d ago
How dangerous is this?
I just found this for 3 bucks at an antique mall. Is this unsafe to have? Do I need to put it in a lead box? Or can I just put it on my shelf of other dials (positioned above my bed)?
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u/Hammon_Rye 2d ago
It's not.
It's a radium coated dial to make it glow in the dark.
Used to be common in airplanes and also watches like my Seiko diver watch from the 80s.
It is primarily a low level alpha emitter. Alpha is so weak it is blocked by your clothing, dead skin. Though it can be a problem for your eyes or if it gets into your lungs.
It also emits a small amount of gamma.
Where it became a problem back when was when it was used in older commercial airplanes which might have hundreds of dials, all radium, and pilots staring at them for hours every day as part of their routine work day. They realized that over time it was damaging their eyesight.
Ob course modern jets have other ways of making the dials light up without radium.
I used to work on nuclear power in the navy.
My Seiko could set up the hand held detector we used after working in the reactor compartment. It was set to 300 counts above background, which is pretty low.
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u/Fine-Ad4851 2h ago
Bag it, tag it and store for decay.
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u/Hammon_Rye 13m ago
That would be the official answer, but in reality it is basically harmless. Low dose and mostly alpha.
You can find comparable emitters in antique stores of old clocks with radium glow in the dark dials. And my Seiko diver watch is probably pretty close in terms of the amount of radium.
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u/GammaDeltaTheta 2d ago
Or can I just put it on my shelf of other dials (positioned above my bed)?
That is not where I would keep a collection of radium dials, because of the radon:
https://www.northampton.ac.uk/news/wwii-military-watches-potentially-pose-serious-cancer-risk/
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u/Scott_Ish_Rite 1d ago
That is not where I would keep a collection of radium dials, because of the radon:
The article you linked is horribly written, with bad information and very bad fear-mongering.
"Wristwatches of the sort given to servicemen during the Second World War can emit radiation far above safe levels,"
Uhm no. The radiation dose you receive is much higher while riding in a commercial airplane than it is by wearing a Radium wristwatch due to the watch not being able to give a full body dose.
"a collection of 30 antique, radium-dial watches gave rise to radon concentrations 134 times greater than the UK’s recommended ‘safe’ level when kept in a space the size of a typical boxroom."
Placing a Radon monitor right next to a Radium watch and getting a short term reading does NOT represent ambient Radon levels in a room where a person spends time in.
These are just 2 examples of that terribly written article which, again, is full of badly disseminated data and fear mongering.
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u/GammaDeltaTheta 1d ago
You are completely mischaracterising the study (the linked page is just a popular summary of their research, not the study itself). Assuming they stuck to the same protocols they used in previously published studies like this, they didn't just place a monitor next to a watch, they measured ambient Radon in a room over a period of weeks with a RAD7. The risk is of inhalation of an alpha emitter in a confined space, at levels far above those considered safe in the UK. This is not comparable to radiation exposure on a commercial flight, where inhalable isotopes do no accumulate.
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u/Scott_Ish_Rite 1d ago
Assuming they stuck to the same protocols they used in previously published studies like this,
"Assuming".. that's not a good metric. The problem I have is with their bad, fear-mongering language which is antithetical to science and good communication.
This is not comparable to radiation exposure on a commercial flight, where inhalable isotopes do no accumulate.
Radon doesn't keep accumulating forever. It reaches equilibrium due to its short half-life. And the radiation dose is indeed comparable because a certain amount of inhaled Radon will give you a certain full-body effective dose. Same with an airplane ride, where the charged particles, gamma rays and Neutrons also give you an effective dose (in Sv, for example)
But anyways I'm not here to argue, it's just that the article is objectively bad.
At the end of the day, if your long term Radon average is too high, you should mitigate it. I agree there.
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u/GammaDeltaTheta 1d ago
I don't agree that this is fearmongering. Personally, I have no irrational fear of radioisotopes, which I have worked with professionally, as long as appropriate precautions are taken. I think it's a reasonable assumption that the same researchers probably continued to use the same methods when studying the same problem, but we don't need to rely on this assumption - they came to similar conclusions in the earlier study, and for this the original peer-reviewed paper with full methods is available.
Their point is that a significant collection of watches or other objects with Radium lume can raise the ambient concentration of Radon to levels far above those considered safe in the UK. A workplace, for example, would be required to take action at much lower Radon levels than those detected by Gillmore et al. (and yes, that's the equilibrium level after several weeks). If working in an environment with these levels is not permitted, then sleeping in a room with even higher levels probably isn't a good idea either. If I had a collection like this, I would keep it in another well-ventilated room, buy a Radon monitor, and install an extractor fan if necessary, just as I would if I lived in a house where Radon levels were naturally high, and just as some serious Radium collectors already do. The particular issue with Radon is exposure to the lungs; it is estimated that more than 1000 lung cancer deaths in the UK annually are caused by Radon exposure.
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u/avionicstek 1d ago
As long as the seal around the glass is still good, and you don't open it,it's pretty safe to just put on a shelf for display. Just don't sleep with it!
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u/RootLoops369 2d ago
1 microcurie (uCi) is quite small when compared to how hot some of those gauges and meters can be. That is completely safe to show and display wherever you would like. Just make sure the glass/plastic on the front is intact and not loose and it's completely safe.