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Re: [OM] Radioactive glass

Subject: Re: [OM] Radioactive glass
From: Kennedy McEwen <rkm@xxxxxxxxxxxxxxxxxxxx>
Date: Wed, 6 Aug 2003 18:47:23 +0100
In article , Joe Gwinn <joegwinn@xxxxxxxxxxx> writes

Whoa! It's not nearly that dangerous, as it's very difficult to get the thorium out of the glass, even if the glass is reduced to powder.

Its not an issue of getting the radioactive elements out of the glass. It is what happens to the alpha emission once you have ingested any of the fine glass particles or dust. Alpha radiation, not the decaying element, is then absorbed by LIVE tissue and that is the danger and the case of carcinogenic mutation.

Nor is there all that much thorium in the glass, or the lenses would be too radioactive for public sale to be permitted.

Its enough to cause a significant discoloration after only a small fraction of the material decays. Much more radioactive materials are openly sold to the public - cut open a smoke detector and poke that in front of a geiger counter, for example. Its only a microgram or so of americium, but its still poses a significant radiation hazard if you swallow it.

And, they would glow in the dark.

The acceptable safe levels for ingested alpha emitters are extremely low and expecting dust to glow in the dark before any danger level is reached is a complete misunderstanding of radiation hazards. The problem is compounded because you have no way of knowing how much of the dust you are likely to ingest or how long it will stay in your body.

In short, these lenses are no more dangerous than any other photographic lens.

In their normal form they pose no danger whatsoever, and I believe I made that clear enough. If it was a danger in its normal form then it wouldn't be much use as a photographic lens, would it? All your film would be fogged!

The danger is very real and significant when the lens is pulverised as indicated on Brian's web site in an area where the dust could easily be ingested.
--
Kennedy
Yes, Socrates himself is particularly missed;
A lovely little thinker, but a bugger when he's pissed.
Python Philosophers

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