Edouard Bastarache on sun 7 sep 03
Hello again Ron,
First of all, let us remember that barium is not regulated anywhere
in the world when it comes to its fate in fired ceramic glazes.
Only two (2) are, lead and cadmium and the latter is an even more
noxious because its half-life may largely exceed 10 years so that a
worker may develop the intoxication a very long time after the
cessation of exposure as in retirement or lay-off.(EB)
" I can ask - how do you prove there is no adverse affect. "(RR)
This morning I searched three (3) of the best databases in our field :
1-Nioshtic &Oshline
2-MedLine,
3-Toxline
I tested the following expression " barium carbonate " + pottery
and nothing showed up on my screen. Barium compounds have been
around for decades so if something was known about their toxic role in
pottery making and using, I would have gotten something to chew on.
Plus, read my text already on the Net based on some of the best world
references in toxicology and you will get the same answer;
I do not think I am fool enuff to hide important information in a text
destined to potters and the ceramics industry.(EB)
" How do we prove that there is no danger to a 1 pound fetus.
Should be at least not warn expectant mothers that there is a
poison leaching out of a glaze? "(RR)
Same comment as above plus the following :
A-From my own text on the Net :
1-Carcinogenesis:
Barium chromate(VI) is the only compound recognized as carcinogenic in man.
2-Mutagenesis :
Barium chloride dihydrate was not mutagenic in Salmonella typhimurium, nor
did it induce sister chromatid exchanges or chromosomal aberrations in
cultured Chinese hamster ovary cells.
3-Developmental effects :
In a mating trial, no adverse anatomical effects were observed in the
offspring of rats or mice receiving up to 4000 ppm barium chloride dihydrate
in the drinking water, although rat pup weight was reduced.
4-Reproduction :
In rats and mice receiving up to 4000 ppm barium chloride dihydrate in the
drinking water, reproductive indices were unaffected.
B-From Le Répertoire Toxicologique de la CSST(Our own OSHA) :
In PMSD, which stand for " Programme Maternité Sans Danger "
(Pregnancy without Hazards) :
Effets sur le développement :
"Aucune donnée concernant le développement prénatal n'a été trouvée dans les
sources documentaires consultées."
Nothing was found in the sources searched. And they searched 35 of the best
references
in the field. If you want a list of them I can send.
I work on this program 2 mornings a week in my area, for 20 years I have
been responsible for this program in our industrial region.(EB)
" I simply would not use materials in a liner glaze that I know or suspect
or have reason to believe - that those materials might have adverse affects
on human health - unless the glaze was at least relatively stable. It is not
a question of the law - it is a question of morality. "(RR)
Morals have nothing to do with toxicology. Two (2) different and too
different fields(EB)
" Woo Yellow is a grossly unstable glaze - it has 30% barium Carb. in it -
there is no question in my mind - I do not know if it is a danger to
anyone - I do know enough to think it might be - what else do I have to
know?
On top of all this - the glaze will change colour when in contact with
acidic food, it will change colour, it is a matte glaze that will mark with
cutlery, and it will sound awful when cutlery is dragged across it - and I
think it will craze on most bodies as well -
I will do a test on my next kiln load and report back with the results.
"(RR)
I checked the notes I have on this glaze and it is said that it is matt when
thinner and
semi-gloss when thicker. It is certainly a noisy job to eat from a matt ware
but,
utilitarian wares are not the only things we make.(EB)
" On another note - Yes - young and the olds are always at greater risk - so
are you suggesting we label certain things as off limits to them? " (RR<)
No(EB)
Finally, searching the databases using the expression " barium+pottery "
I found the following abstract, which is very comforting for potters when
it comes to discussing the potentially toxic kiln emissions. The conclusion
is :
" Almost all measured values were well below permissible concentrations.
"(EB)
Kiln emissions and potters' exposures.
Authors:
HIRTLE B
TESCHKE K
VAN NETTEN C
BRAUER M
Author Address: Univ. B.C., Dep. Health Care Epidemiol., Vancouver, BC,
Canada.
Source: AMERICAN INDUSTRIAL HYGIENE ASSOCIATION JOURNAL; 59 (10). 1998.
706-714.
Abstract:
BIOSIS COPYRIGHT: BIOL ABS. Some ten thousand British Columbia potters work
in small private studios, cooperative facilities, educational institutions,
or recreation centers. There has been considerable concern that this
diffuse, largely unregulated activity may involve exposures to unacceptable
levels of kiln emissions. Pottery kiln emissions were measured at 50
sites-10 from each of 5 categories: professional studios, recreation
centers, elementary schools, secondary schools, and colleges. Area
monitoring was done 76 cm from firing kilns and 1.6 m above the floor to
assess breathing zone concentrations of nitrogen dioxide, carbon monoxide,
sulfur dioxide, fluorides, aldehydes, aluminum, antimony, arsenic, barium,
beryllium, boron, cadmium, chromium, cobalt, copper, gold, iron, lead,
lithium, magnesium, manganese, mercury, nickel, selenium, silver, vanadium,
and zinc. Personal exposures to the same metals were measured at 24 sites.
Almost all measured values were well below permissible concentrations.
Later,
"Ils sont fous ces Quebecois"
Edouard Bastarache
Irreductible Quebecois
Indomitable Quebeker
Sorel-Tracy
Quebec
edouardb@sorel-tracy.qc.ca
http://sorel-tracy.qc.ca/~edouardb/
http://perso.wanadoo.fr/smart2000/index.htm
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