Monona Rossol on fri 18 sep 98
---------- Forwarded message ----------
From: agrez
To: CLAYART@LSV.UKY.EDU
Subject: URANIUM?
----------------------------Original message----------------------------
While reading the book "Ceramics-and how to Decorate Them" by Joan
Priolo, c. 1971, I came across the following paragraph:
"Uranium produces reds and oranges of varying shades. Between
5% and 8% is generally used to color a glaze. Too much uranium
will result in a black glaze. You may encounter some difficulty
in obtaining uranium now for the obvious reason that it is in
great demand for other less artistic, purposes."
Is it true that this was once used in glazes? When was it disallowed,
and is there a possibility that the older collectibles that I have
scattered around my house are radioactive...or is there another,
non-radioactive uranium of which I am unaware?
Regards, Andrea Grez, wondering about that black glaze covering a cute
little vase she inherited from her great aunt; thinking it might look
cuter in a lead lined box.
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Uranium was commonly used in glazes. Fiesta Ware and many collectible wares
are uranium glazed.
Uranium is still not banned for use in glazes, but that is because when the
Nuclear Regulatory Commission studied the problem they didn't find it in use
any more. I tried to tell them that there are tons of individual small
potteries still using uranium, but they had no way to check on the little
guys. They did ban uranium enamels because there were a lot of foreign
enameled jewelry coming into the country ticking.
And if you are looking for radioactive collectibles, take a look at glass.
Even depression glass is colored with uranium. Vaseline glass, and many
others employ uranium.
As for pottery, I refer you to two papers:
Accidental contamination from uranium compounds through contact with ceramic
dinnerware, Ralph W. Sheets, Clifton C. Thompson, The Science of the Total
Environment 175(1995)81-84
Release of uranium and emission of radiation from uranium-glazed dinnerware,
Ralph W. Sheets, Sandra L. Turpen, Department of Chemistry, Southwest
Missouri State University, Springfield, MO 65804--accepted for publication by
the Journal of Radioanal. Nucl. Chem.
And if you are truly fascinated by this problem, contact me in private and
I'll connect you up with Ralph Sheets who is the absolute expert on the use
of radioactive glazes and glass.
ANd I would like to appeal to Clayarters to help me find a publisher for a
monograph written by Ralph Sheets called: "Uranium-glazed Ceramic Dinnerware:
History, Manufacture, and Physical and Chemical Properties." I've read all
70+ typed pages and it is super.
Monona Rossol
ACTS
181 Thompson St., # 23
New York NY 10012-2586 212/777-0062
http://www.caseweb.com/acts/
ret on sat 19 sep 98
from Monona
---------- Forwarded message ----------
Date: Thu, 17 Sep 1998 23:04:23 -0400
From: Monona Rossol <75054.2542@compuserve.com>
To: ret
Subject: Re: URANIUM? (fwd)
---------- Forwarded message ----------
From: Bruce Girrell
To: CLAYART@LSV.UKY.EDU
Subject: Re: URANIUM?
----------------------------Original message----------------------------
> I just had to respond to this one (see below). First, though, I can answer a
> little bit. The answer is definitely Yes, uranium was once used[1]. There
> are two primary isotopes of uranium U-238, the common stuff, and U-235, the
> much rarer, fissionable stuff once used for an atomic bomb. Most raw uranium
> oxide ore is mostly U-238 with a tiny amount U-235. It slightly
> radioactivity, though. There is also some concern about radon, a decay
> product of uranium and radium[4]. <
Don't forget U-234. And depleted uranium is more than "slightly" radioactive.
> Probably more serious is its chemical toxicity (Monona, are you around
> today?). Uranium oxide has a chemical toxicity similar to that of lead
> oxide[4]. <
The OSHA PELs are the same indicating they are equally controlled in the
workplace air. However, their modes of toxicity are quite different. Lead
primarily damaged the nervous system and will also ultimately harm the
kidneys. Uranium is a potent kidney toxin, and doesn't do much to the
nervous system.
> Bottom line: Don't use it. <
I second that.
> As far as the collectables around your house go, I wouldn't worry about
> them. Since you probably don't eat out of them (they probably have lead in
> the glaze as well) they present little, if any, danger to you. The degree of
> radiation that you could get from one of these pieces is much less than you
> would get from taking an airplane ride. Remember that many clays are
> radioactive, too (potassium 40 primarily). If it really worries you, though,
> borrow a geiger counter (schools often have them) and survey the objects in
> your house. >
In a previous post, I listed two papers on this subject. Now I'm going to
type in the abstracts:
Accidental contamination from uranium compounds through contact with ceramic
dinnerware, Ralph W. Sheets, Clifton C. Thompson (see earlier post for rest)
ABSTRACT: Examination of orange-colored dinnerware samples purchased in
antique stores and flea markets has revealed the occasional presence of
surface uranium compounds that are readily transferred to the hands and
clothing. We have further been able to produce soluble uranium compounds on
the surfaces of clean dishes by exposing them to household vinegar or
bleach. We estimate that handling of a contaminated dish can transfer up to
1-2 becquerels or more or uranium compounds to the hands. Uranium
contamination is of concern because the element is not only an alpha emitter
but also a chemical nephrotoxin. Although the amount of uranium likely to
be ingested as a result of casual handling may be small, it could still
exceed by several times the amount occurring in the average diet (about 40
mBq/day). Furthermore, since fresh surface compounds are readily formed, it
is possible that a person who regularly handles or eats from uranium-glazed
dinnerware can accidently ingest significant amounts of uranium.
Release of uranium and emission of radiation from uranium-glazed dinnerware,
Ralph W. Sheets, Sandra L. Turpen (rest in previous post)
ABSTRACT: Samples of orange, yellow, beige, ivory and blue-green ceramic
dinnerware glazed with uranium compounds have been examined. Measurements at
glaze surfaces yielded exposure rates of 3.8-16 mR/h (1-4 uC/kgh) for orange
glazes and rates of 0.04-1.3 mR/h (0.01-0.3 uC/kgh) for ivory, beige, and
yellow glazes. Whole body exposure from a shelf display of 40 orange dishes
was estimated to be 0.1-0.5 mR/h(0.03-0.13 uC/kgh), or up to 50 times the
room background radiation level, at a distance of 1 meter. Twenty-four hour
leaching tests of orange, yellow, and ivory dishes were carried out with
various concentrations of acetic and citric acids. Uranium concentration in
leachates of some orange dishes exceeded 450 mg/L. Uranium is a chemical
nephrotoxin and the United States Environmental Protection Agency has
proposed a maximum contaminant level for drinking water of 0.020 mg/L. Based
on this value a person consuming 2.2 L of drinking water per day would ingest
0.31 mg of uranium per week. A person eating once a week from an orange
glazed dish could easily ingest 10 or more times this amount.
I ask clayarters to read this information carefully and remember
especially that Sheets found that standing 1 meter away from a display of
40 dishes increased radiation 50 times above room background. Handling
dishes transferred significant amounts of uranium. And you'd have to be nuts
to eat from them.
And we all know---if we go back into clayart archives---that there are
potters who care so little about their customers that they still use
uranium. Worse, they defend its use, make jokes about it, and convince
others that those of us who worry about such things are wimps.
I'm only sorry I didn't have access to this research when the subject came up
before.
Monona
Arts, Crafts and Theater Safety
181 Thompson St., # 23
New York NY 10012-2586 212/777-0062
http://www.caseweb.com/acts/
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