I inherited my grandfather’s WWII compass, and had it sitting around for a long time on a shelf. I recently got a Geiger counter, and find that it’s radioactive. Around 10 microsieverts/hr. Apparently they used radium paint to make them glow in the dark. I can’t just throw it away, but I don’t want it potentially causing a danger to others in the room. Is there some sort of lead lined box I can put it in, or some kind of prevention I can do? Is there anyone experienced with this sort of thing that can offer some advice?
Nuclear physicist here!
I agree with the general consensus in the comments. Alpha radiation from radium is easily stopped by a few centimeters of air, a sheet of paper, and even the dead layer of cells on the outside of your skin. So long as you don’t eat, inhale or inject the radium, you’ll be fine.
I wouldn’t keep it on your person for an extended period of time though - for example carrying it in your pocket every day, sleeping with it under your pillow, etc. Store it somewhere safe and not immediately next to your skin; the back of a drawer or on a shelf would be fine. Feel free to use it or show it to people from time to time. That’s a neat piece of history to have!
Just in case, keep a label or warning text with it wherever you store it, OP.
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Assuming the majority of the material on it is still Radium, the good news is it’s mostly undergoing Alpha decay - which can be stopped by something as simple as your skin. Depending on the decay chain, there’s also probably a bit of Beta decay in there, for which a strong metal box will probably suffice.
But the real point here is that 10 uSv is the radiation equivalent of being alive for an average day, so brief exposure is unlikely to cause real injury. But here are some things you can do if you’re still concerned:
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Limit time exposed to it. It’s okay to take it out to show to friends and family, but otherwise keep it somewhere people aren’t likely to be nearby.
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The aforementioned metal box.
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Wash your hands thoroughly after handling, and/or wear gloves. It’s unlikely, especially if the radium-painted parts are under glass, but possible that radioactive materials could end up on your skin. Washing hands should prevent this.
If you’ve heard of the “Radium girls”, the thing that really made them sick is that they were licking radium-coated paintbrushes, causing radioactive material to end up inside their bodies. Since (I presume) you’re not licking the compass, you’re much less at risk.
Knowing the dosage is a day’s exposure, and only if you expose yourself to if for an hour, makes me feel much safer about taking it camping once in the be 90s. In general, no one touched it for fear of breaking it.
We’re keeping it in the garage on a shelf, next to a window from now on. With a label.
Thank you!
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I wouldn’t worry about it - you are largely only going to harmed if you ingest any flakes of radium paint. If the compass is sealed and you use gloves when handling it you should be fine. If you wanted an extra level of security you could buy a perspex display box to put it in so, even if it wasn’t sealed and paint was flaking off it, no-one close to it would come in contact with it.
Have a read of this for more information.
I spent years working with radioactive materials in a lab and, as long as you aren’t careless it’s not a worry - there were much more dangerous things in there that genuinely scared me (like hydrofluoric acid).
It’s in really good condition, and checking the shelf where it’s been sitting for a decade, there no residual radiation. So I have to assume it won’t flake off easily.
A perspex box might be a good idea, but for now it’s sitting on a far away garage shelf with a label. I’d prefer to keep it even if it’s an outdated method compared to my phone, as it was a gift from my grandfather as he had it from his deployment in WWII in the 45th infantry. But now we’re all aware of what it might do, so we’ll definitely limit exposure time if we do show it off. It’s good to know that it’s still a fairly small amount of danger, comparatively.
Thank you!
Sounds like you should be fine. Most radioactive particles don’t travel far or penetrate very far (why the main danger is from ingestion) so if you aren’t carrying it around and it’s not in a high traffic area of the house then you should be fine. If you want to be sure, you can pop it into ziplock bag.
You reminded me of this:
That’s handy and I’m bookmarking it for quick reference. I have one for the Geiger counter, but it’s just numbers and doesn’t have examples.
Thanks!
The beta emission is trivial and harmless. Alpha particles travel 7cm in air, glass absolutely stops it. A sheet of paper would.
Its perfectly safe to wear.
The paint on the watch hands contains radium and decay products but in tiny amounts. If the crystal broke wipe cup the dust with damp paper towel. Itsjust not that big a deal.
Itvwss most dangerous to the people whomade them, exposed daily during a career. Andcl the placecthst had gallons of thecshit laying around.
One old watch is harmless
It’s a compass though :-)
You don’t wear your compass? How do you know where to go?
I walk at a constant speed and use my wristwatch to measure time, so I can calculate distance :-)
You might try asking Mackie about this. Not sure if they’re still active or maybe lurking, but they literally have a lil’ community for old uranium glass products which may mean they have just the sort of insight you’re after.
leaded glass display case?
I don’t think you’d need to do anything too extreme for that low of a level of radiation. If you want to keep it, it should be fine in a drawer in a dry, well-ventilated room. Just don’t hold it bare-handed for extended periods, and don’t somehow swallow a piece of it, and you should be fine. Also wash your hands after handling it, as you may get radioactive particles on your skin. If you’ve got children in your home, it might be a good idea to make sure it’s inaccessible to them, either somewhere they can’t access or somewhere with a lock.
If you’d rather not hang onto it, I believe you can contact the EPA, who can refer you to a local facility that can properly dispose of it for you. Or maybe check out some local groups to see if there are any collectors that would prefer to take it off your hands, as they may be more likely to preserve the piece for you, if it has any sentimental value to you.
It’s a “family heirloom” as my grandfather had it in WWII for the 45th infantry. So I wouldn’t want to dispose of it, but I can see my initial fears may be a bit overblown. I’m keeping it on a shelf in the garage, far away from normal foot traffic. That should be more than sufficient, it sounds.
I definitely used it while camping once, but thankfully no one’s messed with it for decades as we wanted to preserve it. I checked the shelf and there’s no residual radiation where it sits, so I think I’ll just let it be. Everyone in the family is aware that it’s the highest radioactive thing in the house, and that it’s still fairly low.
Thank you for your help!
