RE: uranium in histologic procedures/soluble, depleted, natural U
|From:||Jim at ProSciTech <email@example.com>|
A few years ago the J Microscopy (V 106, 85-86, January 1976) published my
paper "Potential hazards of uranium and its compounds in electron microscopy: a
brief review. Uranyl nitrate in terms of toxicity and radioactivity is
virtually identical to U acetate.
The radioactivity of 1% uranium nitrate is minimal and a small volume would
emit less harmful radiation than a smoke detector or the back of a computer
screen - and I 'm not suggesting that smoke detectors or screens in normal use
What danger there is relates to the chemical toxicity of SOLUBLE uranium
compounds. These are powerful kidney poisons and they are more toxic than
Don't eat or drink or touch soluble uranium compounds! In histo labs the
quantities used are small and with basic precautions there should be no
trouble. I have never heard of a case of kidney poisoning due to U compounds in
histo or EM labs.
The good news is that these compounds are not accumulated, in fact they are
The issue of "depleted U" is totally irrelevant to chemical toxicity.
Uranium metal is not soluble in body fluids and its danger is from radiation
and this relates to quantity of the metal, the isotopes present, distance and
The most damaging to human health, may be small U particles. These are inhaled
and can sit in the lung "forever". They are not detectable by blood tests and
irradiate the lung with a large range of radiation, some of which are quite
powerful. Particles in the lung would be very small, but they are at very close
range to unprotected tissues.
A daughter product of several U isotopes in natural and depleted U is the very
heavy (in fact the heaviest known gas) radon. Both radon and radiation are
known to cause cancers, radon infamously so. (Early underground U miners died
by the thousands in poorly ventilated shafts. This is peripheral to this
server, but when 3000 tons of U is vaporized, as it was in Bosnia, it stands to
reason that some of this was inhaled by anybody within miles, particularly
downwind. So some histologist just may come across U particles in a lung.
"Depleted U"? Yes, the most powerful radiation is that of the isotope U235,
which in natural U amounts to 99.3% of the total. Depletion of that isotope is
not done to make the U safer, but to enrich some U for use in reactors and to
make bombs. Depleted U is the cheap by-product and so it is used as a counter
weight in the tail fin of jumbo jets (300kg!).
It appears that depletion rarely is to less than 0.3% of U235. In any case, the
word depleted just means that this material would be most expensive to use for
the production of enriched uranium. It is acknowledged that there is a
difference in radiation between depleted and natural U, but its minimal. It
appears that a lot of people have been fooled by the "depleted" label; it seems
that we have been led to think that natural uranium was much safer, which is
not the case.
Depleted is not the most important issue with U and its compounds. Is it
soluble, is it in small particle form and how much is there? These are the more
important health considerations.
ProSciTech Microscopy PLUS
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On Saturday, February 10, 2001 4:27 AM, Weems, Joyce [SMTP:JWEEMS@sjha.org]
> We purchase the 1% from PolyScientific. It's warnings would scare the pants
> off ya! Nothing about being depleted.
> Joyce Weems
> Pathology Manager
> Saint Joseph's Hospital of Atlanta
> -----Original Message-----
> From: RSRICHMOND@aol.com [SMTP:RSRICHMOND@aol.com]
> Sent: Friday, February 09, 2001 12:20 PM
> To: HistoNet@pathology.swmed.edu; PATHO-L@listserv.cc.emory.edu;
> Subject: uranium in histologic procedures
> Uranium nitrate (uranyl nitrate) is used in a few histologic stains,
> particular silver impregnation stains, including a recently
> discussed stain
> for Helicobacter. Questions are often raised about its radiotoxicity
> chemical toxicity. A recent editorial in The Lancet is informative.
> Toxicity of depleted uranium - by N.D. Priest (School of Health,
> and Environmental Sciences, Middlesex University, London N11 2NQ, UK
> email@example.com) The Lancet 27 Jan 2001; 357: 244-6. (I suppose
> it's on
> the Web, but I've got a paper copy.)
> Priest describes depleted uranium as uranium from which 70-80% of
> the highly
> radioactive U-235 and U-234 have been removed. Depleted uranium has
> come into
> commercial use in several settings, including X-ray shielding in
> but it has recently gained notoriety because of its use in
> munitions in the former Yugoslavia (and in fact earlier, in the Gulf
> Of histologic interest is the statement that "Depleted uranium has
> uranium of
> natural isotopic composition as a less radioactive substitute for
> some uses -
> e.g., laboratory chemicals." Is this substitution stated on labels?
> I don't
> have a recent label to check. - The substitution is not sufficient
> to affect
> computations at the level of precision needed in histologic work.
> Priest's review suggests that the need for chemical or radiologic
> with handling uranyl salts is not very great from a practical
> viewpoint -
> though what keeps the Herrn Inschpektors happy is another question.
> (Parenthetically, some bottles of lithium carbonate note that the
> lithium has
> been depleted of lithium 6 - used in making tritium for hydrogen
> bombs - and
> this substitution might actually be of soposition.)
> I've cross posted this note to the pathologists' PATHO-L list and to
> histologists' Histonet.
> Bob Richmond
> Samurai Pathologist
> Knoxville TN
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