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
< This message was delivered via the Olympus Mailing List >
< For questions, mailto:owner-olympus@xxxxxxxxxxxxxxx >
< Web Page: http://Zuiko.sls.bc.ca/swright/olympuslist.html >
|