Tim Dippold on tue 22 jun 99
Would you like to Know the truth about cobalt and food safety? Are you
afraid you are being exposed to a chemical that is toxic? Well fear not
fellow potters because Cobalt is NOT toxic! It is about as virulent as iron
and is almost as important to your body, especially your liver. COBALT IS
NECESSARY FOR THE PRODUCTION OF VITAMIN B12. Most of the cobalt used for
industry goes to agriculture where it is used in fertilizers and feed. Then
comes the metal industry which uses it to make harder alloys and control
nuclear fission in our nuclear power plants because cobalt doesn't undergo
any sort of nuclear reaction. Painters and then potters are at the bottom of
the list and cobalt is used by painters not just for pigment but as a drying
compound for oilpaints. Cobalt isn't that rare of an element. It is found
almost every where such as Africa, China, Japan (around Seto I believe)
Russia here in the US. I have heard of cobalt deposits around Boulder
Colorado. Whether or not there is enough to mine to warrant the high cost of
refining it is another question all together.
Tim Dippold setewall@hotmail.com ;~)
_______________________________________________________________
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Gavin Stairs on wed 23 jun 99
At 08:54 AM 22/06/1999 EDT, you wrote:
>----------------------------Original message----------------------------
>Would you like to Know the truth about cobalt and food safety? Are you
>afraid you are being exposed to a chemical that is toxic? Well fear not
>fellow potters because Cobalt is NOT toxic! It is about as virulent as iron
>and is almost as important to your body, especially your liver. COBALT IS
>NECESSARY FOR THE PRODUCTION OF VITAMIN B12. Most of the cobalt used for
>industry goes to agriculture where it is used in fertilizers and feed. Then
>comes the metal industry which uses it to make harder alloys and control
>nuclear fission in our nuclear power plants because cobalt doesn't undergo
>any sort of nuclear reaction. Painters and then potters are at the bottom of
>the list and cobalt is used by painters not just for pigment but as a drying
>compound for oilpaints. Cobalt isn't that rare of an element. It is found
>almost every where such as Africa, China, Japan (around Seto I believe)
>Russia here in the US. I have heard of cobalt deposits around Boulder
>Colorado. Whether or not there is enough to mine to warrant the high cost of
>refining it is another question all together.
I'll only pick out one, obviously wrong statement here; the one about
cobalt not undergoing any reaction in nuclear reactors. This is about as
wrong as it is possible to get. Cobalt has a large neutron absorption
cross section, which is a technical phrase meaning that cobalt readily
absorbs neutrons in the reactor. That is why it works as a control.
Inserting cobalt control rods into the reactor core dampens the nuclear
fire, like throwing water on a piece of burning wood. In the process,
cobalt becomes the highly radioactive, long lived isotope, cobalt60. In my
line of work, we have to place stringent limits on cobalt in other metals
precisely to avoid this effect, which would otherwise make our physics
apparatus too hot to handle after a few year's exposure in the experiment.
All of which has nothing whatever to do with studio pottery.
As to the vitamin argument, I've already spoken that one. I'll advocate
the addition of leachable cobalt to pottery the day we become licensed as
pharmacists or food additives suppliers.
Gavin
Craig Martell on wed 23 jun 99
-----Original Message-----
From: Tim Dippold
>Would you like to Know the truth about cobalt and food safety? Are you
>afraid you are being exposed to a chemical that is toxic? Well fear not
>fellow potters because Cobalt is NOT toxic!
Hello Tim:
You don't really say anything conclusive about why you have absolutely
determined that cobalt isn't toxic. You just state that it is found in many
locations and used by a broad spectrum of people. Other elements are used
in small amounts by the human body as well and in trace, and small amounts
are not toxic. Chrome and Manganese are examples of this.
Cobalt may not be toxic in small amounts. I have no evidence or knowledge
to state the case, and you really didn't either. Well, maybe you do have
conclusive proof and just left it out of your post.
regards, Craig Martell in Oregon
Edouard Bastarache on thu 24 jun 99
------------------
Hello all,
i did not feel much like writing a review paper on the problem so i am
sending a few scientific abstracts.
First of all, always remember there is a difference in exposure between
pottery factory workers, studio potters, full or part-time and ceramics
teachers.
Later this year i will write somthing more specific.
Later all,
NIOSHTIC RECORD NUMBER : 204421
TITLE :
Incidence of Lung Cancer among Cobalt-Exposed Women
NIOSHTIC CONTROL NUMBER : NIOSH-00234943
AUTHOR(S) :
Tuchsen, F., M. V. Jensen, E. Villadsen, and E. Lynge
SOURCE :
Scandinavian Journal of Work, Environment and Health, Vol. 22, No. 6,
pages
444-450, 25 references
PUBLICATION DATE : 1996-12-00
ABSTRACT :
A retrospective study was done to evaluate the relationship between
occupational exposure to cobalt (7440484) and cancer incidence. A cohort
of
874 women exposed to cobalt through their work in two porcelain
factories in
Denmark and a group of 520 women employed in one of the same factories
with
no cobalt exposure were identified from personnel files. Deaths and
cancer
incidence were traced in the national population register and the
national
cancer register, respectively, and results were compared to the observed
rates for all Danish women. Exposure to cobalt occurred in the process
of
underglazing plates by first spraying cobalt blue dye on bare plates and
later removing superfluous dye from the plates. The dye used was
initially
cobalt-aluminate-spinel (1345160) dye but was replaced by
cobalt-silicate
(12643139) dye in 1972 for workers in one of the factories, and in 1989
for
workers in the second factory. Cobalt content was approximately 25=25 in
both
dyes. Total mortality in cobalt exposed and unexposed workers was the
same
as that for all Danish women, while the cancer incidence was slightly
elevated among the exposed women but unchanged in the reference group.
Both
exposed and unexposed workers showed an increased lung cancer incidence
compared to all Danish women, with the size of the increased risk only
slightly higher in the exposed group compared to the reference group.
The
authors, citing the small number of workers in the study, recommend a
follow
up study after 5 years.
DESCRIPTOR(S) :
SWEHDO / Epidemiology / Cobalt compounds / Lung cancer / Mortality rates
/
Pottery glaze / Long term exposure / Pottery industry
NIOSHTIC RECORD NUMBER : 190283
TITLE :
A 1982-1992 Surveillance Programme on Danish Pottery Painters.
Biological
Levels and Health Effects following Exposure to Soluble or Insoluble
Cobalt
Compounds in Cobalt Blue Dyes
NIOSHTIC CONTROL NUMBER : NIOSH-00221545
AUTHOR(S) :
Christensen, J. M., and O. M. Poulsen
SOURCE :
Science of the Total Environment, Vol. 150, Nos. 1-3, pages 95-104, 24
references
PUBLICATION DATE : 1994-06-30
ABSTRACT :
Cobalt (7440484) exposures and biological levels were studied in plate
painters in two porcelain factories in Denmark from 1982 to 1992. Cobalt
related disease and the carcinogenicity of cobalt were reviewed.
Airborne
cobalt levels and urine levels of cobalt in plate painters were
monitored as
part of the surveillance program. Between 1982 and 1992, with few
exceptions, urine cobalt concentrations have decreased steadily from 100
times higher to 10 times higher than levels found in the control
subjects.
This observation coincided with a reduction of airborne levels of cobalt
from 1,356 to 454 nanomoles/cubic meter, which was attributed to
improvements of the working environment. Prior to this reduction in
airborne
levels, chronic impaired lung function was prevalent among the pottery
workers. Both soluble and insoluble cobalt dyes have been used. In plate
painters exposed to the soluble cobalt dye, urinary cobalt levels were
30
times higher than that found in control subjects and workers exposed to
insoluble cobalt. In experiments on unexposed subjects, the
gastrointestinal
uptake of soluble cobalt was considerably higher than the uptake of
insoluble cobalt. Uptake was significantly higher in females than males.
A
study on lung function in 1982 indicated that cobalt may cause a chronic
reduction in lung function. A study on thyroid function in female plate
painters found no effect of exposure on thyroid function, but did
indicate
an altered metabolism of thyroid hormones. Future epidemiology and
genotoxicity studies planned for this group of workers were described.
DESCRIPTOR(S) :
STENDL / Cobalt compounds / Pottery industry / Airborne dusts / Humans /
Occupational exposure / Biological monitoring / Toxic effects /
Urinalysis /
Surveillance programs
NIOSHTIC RECORD NUMBER : 182413
TITLE :
Contact Dermatitis among Decorators and Enamellers in Hand-Made Ceramic
Decorations
NIOSHTIC CONTROL NUMBER : NIOSH-00213091
AUTHOR(S) :
Gaddoni, G., L. Baldassari, E. Francesconi, and A. Motolese
SOURCE :
Contact Dermatitis, Vol. 28, No. 2, pages 127-128, 8 references
PUBLICATION DATE : 1993-02-00
ABSTRACT :
A study of contact dermatitis among ceramics decorators and enamellers
was
conducted. The study group consisted of 12 men and 38 women employed in
the
Italian ceramics industry. They applied enamels and lacquers to the
pottery
in preparation for on glaze firing. They were given dermatological
examinations that included patch testing with seven chemicals from an
Italian standard allergen series and 22 substances specifically handled
by
ceramics enamellers and decorators. Seventeen subjects reacted to one
patch
each and seven to two or more patches. The two substances producing the
largest number of positive reactions were nickel-sulfate (7786814) and
cobalt-chloride (7646799) which were responsible for 28 and 16=25 of the
positive reactions, respectively. Fourteen subjects with positive patch
tests responses had a history of contact dermatitis. Hand and forearm
dermatitis was found in only three subjects. The authors conclude that
the
ceramics decorators apparently have a low prevalence of active hand
dermatitis despite a high frequency of sensitization as indicated by the
positive patch test responses and previous histories of contact
dermatitis.
Ceramic decorating and glazing may cause sensitization, but not
necessarily
clinical dermatitis.
DESCRIPTOR(S) :
CODEDG / Contact dermatitis / Pottery industry / Occupational exposure /
Patch tests / Allergens / Painting / Skin disorders
NIOSHTIC RECORD NUMBER : 150736
TITLE :
Health Effects due to Occupational Exposure to Cobalt Blue Dye among
Plate
Painters in a Porcelain Factory in Denmark
NIOSHTIC CONTROL NUMBER : NIOSH-00186005
AUTHOR(S) :
Raffn, E., S. Mikkelsen, D. G. Altman, J. M. Christensen, and S. Groth
SOURCE :
Scandinavian Journal of Work, Environment and Health, Vol. 14, No. 6,
pages
378-384, 23 references
PUBLICATION DATE : 1988-12-00
ABSTRACT :
A study of the health effects associated with occupational exposure to
cobalt (7440484) in porcelain workers was conducted. The cohort
consisted of
46 female plate painters exposed to cobalt blue underglaze in a Danish
porcelain factory. The comparisons consisted of 51 female top glaze
painters. The subjects completed a questionnaire, and were given a
physical
examination, and pulmonary function tests=3B blood and urine samples =
were
analyzed for cobalt. Standard hematological parameters were determined.
The
cohort was examined after the factory had been shut down for 6 weeks,
and
again 29 days after the subjects resumed work. The prevalence of itching
skin, nose, mouth, and throat irritation, cough, expectoration, and
exertional dyspnea was significantly greater in the cohort than in
comparisons. Irritative symptoms increased after the plate painters
resumed
work. Mean blood cobalt concentrations in the plate painters after the
workfree period and after resuming work were 8.05 and 36.7 nanomoles per
liter (nmol/l), respectively. Mean blood cobalt concentrations in the
comparisons averaged 4.04nmol/l. Mean urine cobalt concentrations in the
cohort after the workfree period and after resuming work were 8.82 and
141.8
nanomoles per millimole creatinine (nmol/mmol), respectively. The
comparison
value was 1.53nmol/mmol. Urine and blood cobalt concentrations were not
significantly related to length of employment as a plate painter or
smoking
habits. The cohort showed increased airflow obstruction which increased
after they returned to work. The plate painters had small, significant
decreases in hematocrit and mean erythrocyte volume after they resumed
work.
These changes were not correlated with blood or urine cobalt
concentrations
or smoking habits. The authors conclude that the plate painters have
significantly elevated blood and urine cobalt concentrations.
Considering
the toxicity of cobalt, this finding should be a cause for concern.
DESCRIPTOR(S) :
SWEHDO / Occupational exposure / Metals / Blood tests / Urinalysis /
Pulmonary function / Pottery industry / Pottery glaze / Humans
NIOSHTIC RECORD NUMBER : 100296
TITLE :
Sensitization To Cobalt In Pottery Workers
NIOSHTIC CONTROL NUMBER : NIOSH-00137773
AUTHOR(S) :
Pirila, V.
SOURCE :
Acta Dermato-Venercologica, Vol. 33, pages 193-198, 9 references
PUBLICATION DATE : 1953-00-00
ABSTRACT :
Incidence of sensitization to cobalt (7440484) in pottery workers was
investigated. A total of 641 workers employed from 1 week to 35 years
were
examined. Patch tests were performed with cobalt-nitrate (10141056) on
436
of the workers. In the clay shops and some other departments, the
relative
number of dermatitis cases was considerably higher than in departments
where
only finished wares were handled or decorated. A positive reaction to 5
percent cobalt-nitrate was obtained in 12 cases. The reaction caused
large
vesicles in 9 cases and was weak in 3. Eleven of the 12 positive
reactions
and all reactions were obtained in the clay shops, where 3 percent of
the
277 workers examined reacted strongly to cobalt. Over 40 percent, or 8
out
of 19 cases of dermatitis of more than 1 month's duration in the clay
shops,
reacted strongly to 5 percent cobalt-nitrate. In the ninth case with a
strong reaction, only formed wares were handled and dermatitis occurred
only
in summer months. In the other 8 cases, dermatitis occurred when
handling
clay containing cobalt and conditions improved during weekends and
holidays.
Dermatitis disappeared without preventive measures when clays not
containing
cobalt were used. The dermatitis was of the erythematous,
papulovesicular or
vesicular type, and localized in the flexor surfaces of the forearms and
on
the backs of hands. Cases varied in severity but were mild enough to
enable
workers to continue work. The author concludes that most cases of
sensitivity to cobalt occur in departments where the clay itself is
handled.
DESCRIPTOR(S) :
ADVEA4 / Clinical symptoms / Physiological response / Dermatology /
Toxic
effects / Skin exposure / Occupational exposure / Biological effects /
Clinical diagnosis / Allergic disorders
Edouard Bastarache
edouardb=40sorel-tracy.qc.ca
http://www.sorel-tracy.qc.ca/=7Eedouardb/
-----Message d'origine-----
De : Gavin Stairs =3Cstairs=40stairs.on.ca=3E
=C0 : CLAYART=40LSV.UKY.EDU =3CCLAYART=40LSV.UKY.EDU=3E
Date : 23 juin, 1999 08:41
Objet : Re: =21The truth about Cobalt Toxicity=21
----------------------------Original message----------------------------
At 08:54 AM 22/06/1999 EDT, you wrote:
=3E----------------------------Original message----------------------------
=3EWould you like to Know the truth about cobalt and food safety? Are you
=3Eafraid you are being exposed to a chemical that is toxic? Well fear not
=3Efellow potters because Cobalt is NOT toxic=21 It is about as virulent as =
iron
=3Eand is almost as important to your body, especially your liver. COBALT IS
=3ENECESSARY FOR THE PRODUCTION OF VITAMIN B12. Most of the cobalt used for
=3Eindustry goes to agriculture where it is used in fertilizers and feed. =
Then
=3Ecomes the metal industry which uses it to make harder alloys and control
=3Enuclear fission in our nuclear power plants because cobalt doesn't =
undergo
=3Eany sort of nuclear reaction. Painters and then potters are at the bottom
of
=3Ethe list and cobalt is used by painters not just for pigment but as a
drying
=3Ecompound for oilpaints. Cobalt isn't that rare of an element. It is found
=3Ealmost every where such as Africa, China, Japan (around Seto I believe)
=3ERussia here in the US. I have heard of cobalt deposits around Boulder
=3EColorado. Whether or not there is enough to mine to warrant the high cost
of
=3Erefining it is another question all together.
I'll only pick out one, obviously wrong statement here=3B the one about
cobalt not undergoing any reaction in nuclear reactors. This is about as
wrong as it is possible to get. Cobalt has a large neutron absorption
cross section, which is a technical phrase meaning that cobalt readily
absorbs neutrons in the reactor. That is why it works as a control.
Inserting cobalt control rods into the reactor core dampens the nuclear
fire, like throwing water on a piece of burning wood. In the process,
cobalt becomes the highly radioactive, long lived isotope, cobalt60. In my
line of work, we have to place stringent limits on cobalt in other metals
precisely to avoid this effect, which would otherwise make our physics
apparatus too hot to handle after a few year's exposure in the experiment.
All of which has nothing whatever to do with studio pottery.
As to the vitamin argument, I've already spoken that one. I'll advocate
the addition of leachable cobalt to pottery the day we become licensed as
pharmacists or food additives suppliers.
Gavin
Ron Roy on thu 24 jun 99
I agree that trace amounts are necessary for good health - but at what
point does it become toxic? Does everyone have the same reaction to over
supply? Can everyone use some more?
Why is it listed as an animal carcinogen? Why is it reported to cause heart
and lung damage?
Perhaps pots which release significant amounts should be permanently labled
"use only if more cobalt needed."
RR
>----------------------------Original message----------------------------
>Would you like to Know the truth about cobalt and food safety? Are you
>afraid you are being exposed to a chemical that is toxic? Well fear not
>fellow potters because Cobalt is NOT toxic! It is about as virulent as iron
>and is almost as important to your body, especially your liver. COBALT IS
>NECESSARY FOR THE PRODUCTION OF VITAMIN B12. Most of the cobalt used for
>industry goes to agriculture where it is used in fertilizers and feed. Then
>comes the metal industry which uses it to make harder alloys and control
>nuclear fission in our nuclear power plants because cobalt doesn't undergo
>any sort of nuclear reaction. Painters and then potters are at the bottom of
>the list and cobalt is used by painters not just for pigment but as a drying
>compound for oilpaints. Cobalt isn't that rare of an element. It is found
>almost every where such as Africa, China, Japan (around Seto I believe)
>Russia here in the US. I have heard of cobalt deposits around Boulder
>Colorado. Whether or not there is enough to mine to warrant the high cost of
>refining it is another question all together.
Ron Roy
93 Pegasus Trail
Scarborough, Ontario
Canada M1G 3N8
Tel: 416-439-2621
Fax: 416-438-7849
Web page: http://digitalfire.com/education/people/ronroy.htm
Mike Bailey on thu 24 jun 99
In message , Tim Dippold writes
Dear Tom.
Snip
>----------------------------Original message----------------------------
>Would you like to Know the truth about cobalt and food safety? Are you
>afraid you are being exposed to a chemical that is toxic? Well fear not
>fellow potters because Cobalt is NOT toxic!
Snip.
I'm sure you are right but as I understand the safety issue, at least in
the U.K., the health and safety concern with cobalt oxide is that its
not pure and contains nickel. We have to put a 'skull & Cross-bones'
symbol on nickel oxide - regarded as carcinogenic.
Cheers,
Mike Bailey
--
Mike Bailey. Bath. U.K.
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