Monona Rossol on fri 13 mar 98
---------- Forwarded message ----------
Date: Thu, 12 Mar 1998 10:13:26 EST
From: Vince Pitelka
Subject: Re: Monona - Toxicity of Mason Stains
----------------------------Original message----------------------------
>Get the ingredients from Mason--if they'll tell you--and avoid the highly
>toxic metals such as cadmium, lead, antimony, chrome, nickel, antimony, etc.
>If they wont tell you, you have no way to judge.
Monona -
I'm curious about this, and would like to hear your opinion. Since Mason
stains are all fritted mixtures, the toxic metals are to some extent
encapsulated in glass. With that in mind, knowing which materials are
present wouldn't necessarily tell us how toxic the raw stain is. To what
degree does this encapsulation shield us from toxic metals in raw Mason
Stains? - Vince
Vince Pitelka - vpitelka@DeKalb.net
Home 615/597-5376, work 615/597-6801, fax 615/597-6803
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
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First, remember, we just went through that "encapsulated" myth. Instead,
they are "included." The zirconium silicate crystals are grown rapidly and
some of the colorant get stuck in them as they grow. After this is done, the
crystals are acid washed to get the really loose stuff out.
But there is not one single study of the finished Mason stains with their
very small crystals and large surface area in animals by ingestion or
inhalation. And some of the stains are indeed "frits" as well.
Making the assumption that somehow "inclusion" or "fritting" will keep the
highly toxic minerals from dissolving in the digestive tract or lungs is a
faulty one. That's the very theory that cost the ceramic glaze
manufacturers dearly in the two law suits last year. In my newsletter I even
quoted Dr. Stopford from ACMI's deposition in these suits in which he
admitted what I have been saying for 20 years that there is no relationship
between acid solubility of frits and bioavailability in the digestive tract.
The thing that finally convinced him was the blood tests on the nursing home
patient who ingested a glaze that leached less than 0.06 % lead on the acid
test and was labeled "lead free."
Our digestive systems use acids, bases, liquids, heat, movement, cellular
mechanisms, enzymes, and more to extracting minerals from stuff. And
Mason stains and frits dusts that get inhaled in the lungs are either
cleared and swallowed or deposited in the alveoli where they can remain
however long it takes to dissolve--years if need be.
OSHA also has looked at what little research there is and decided to make no
distinction between cadmium oxide, cadmium frits, or cadmium stains. Neither
should we.
Monona Rossol
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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