Gavin Stairs on sat 6 apr 02
This is a post from the past. Dear Monona doesn't seem to be with us for
the time being. Let her speak from the crypt of the Clayart archives
instead. She cites a specific study/testimony, and refers to the British
experience with lead bisilicate.
To Edouard Bastarache, irreducible Quebecois, I would pose the following
question: by what route and at what rate do cations which are included in
silicate frits leave the body, if inhaled in small particles which do not
clear effectively by the throat? I presume that any such material except
the most refractory (possibly zirconia) will release its load of stuff by
ion-exchange if immersed in lung fluid for a long enough time. All such
material will also clear from the body by various routes, given a long
enough time. So in my model, it is a matter of competing
rates. Presumably the uptake will be higher the finer the particles, so
the danger may be worst with very fine powders. We are given to understand
that some large fraction of pottery frits may come in very fine particle
sizes. So why should we not be concerned in the case of persistent
poisonous heavy metals in frits and stains? Do you assume that if the
syndrome is not reported in the toxicology literature it does not
exist? Of do you have a firmer basis in science to dismiss the problem?
Gavin
>Date: Fri, 26 Jun 1998 16:51:31 EDT
>From: Monona Rossol <75054.2542@compuserve.com>
>Subject: lead frits safe?
>...
>Please read the Clay Times safety column called "The Frit Myth." It includes
>quotes from deposition testimony of Dr. Stopford from one of the two
>lawsuits against the major lead glaze manufacturers last year (Duncan, Mayco,
>Amaco, and others), information from the Center for Disease Control's MMWR
>on a case of lead poisoning from a non-toxic "lead free" glaze (it contained
>an insoluble frit), and a study that showed no difference between uptake in
>animals by ingestion and by inhalation between lead monosilicate, lead
>bisilicate, and red lead.
>
>Don't be behind the times. It is now very clear that fritting of lead does
>not make it safe. The improvement in health in the British Pottery industry
>in the late 1800 when fritting was introduced was probably due primarily to
>the fact that wet cleaning, hand washing and ventilation were introduced
>simultaneously.
>
>Monona Rossol, industrial hygienist
>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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