Re: Uranium colors

[schoenho@via.at]

At 09:32 21.08.1996 -0500, you wrote:
>I am editing a uranium safety course for use throughout the DOE complex,
>and I have a question about colors.  The course that I inherited contained
>the following statement about yellowcake.
>
>"The final color [of yellowcake] can actually range from yellow to orange
>to black depending on the chemicals used and the drying temperature. The
>final color is important when determining biological effects if uranium in
>this form is taken into the body, as the darker color indicates that the
>material will have a lower solubility, meaning the uranium will stay in our
>body longer.  A lighter color indicates that the material has a higher
>solubility meaning the uranium is more quickly removed by normal body
>functions."
>
>Is it really possible to make such a broad generalization about color and
>solubility?  Is this paragraph helpful?  Does anyone know where this
>information comes from?
>
>There are many other threads that could be pulled from this quote, eg
>obviously low solubility implies low absorption rate as well as low
>clearance rate, so it depends if the intake is inhalation or ingestion.
>Also, the color of materials containing uranium is extremely complicated,
>depending on many things, including impurities, the particle size, and the
>oxidation state or states.
>
>Thanks to several RadSafers who made comments on the draft DOE uranium
>safety course.  If  anyone else would like to see a copy of the draft
>course, please reply to me directly.
>
>"Shlala gashle" (Zulu greeting, meaning "Stay safe")
>mike (mcnaught@LANL.GOV)
>
>====================================================================

Mike,

I want to comment on the biological effects, though I am really no expert in
uranium and yellow-to-black cake. I think it is likely that the solubility
of yellow cake is related to the colour, but as you pointed out you clearly
have to state the way of incorporation - whether it is inhalation or
ingestion. An unsoluble particle will stay in the lung very long if inhaled,
but it will pass the GI tract very fast without causing much dose to the
tissue. A soluble prticle will in the lung be dissolved fast, removed and
excreted relatively fast compared to the insoluble particle. If ingested, it
will be dissolved and will surely stay longer in the body. 

On the other side I am a collector of uranium containing items - most of all
I like the beautiful Bohemian glasses from the 19th century with their
spectrum of all kind of green ("Annagruen"). On tiles you find the deep red
colours produced by glazes containing uranium. But producing these colors is
totally totally different from the question of yellow cake. In minerals
often the presence and absence of hydration water can change colours and
drying may also affect the very complicated chemical composition of the
product - changing the solubility.

I am interested in your draft course. Thank you!

Franz Schoenhofer
Federal Institute for Food Control and Research
Kinderspitalg. 15
A-1095 Vienna, Austria
Schoenhofer
Habichergasse 31/7
A-1160 WIEN
AUSTRIA/EUROPE
Tel./Fax:	+43-1-4955308
Tel.:		+43-664-3380333
e-mail:		schoenho@via.at