Monona Rossol on fri 18 sep 98
From: Chris Schafale
To: CLAYART@LSV.UKY.EDU
Subject: Re: Manganese dangers
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As with all toxicity issues, I think it's worth saying that "it
depends." My understanding about manganese is that the toxicity
problems have been associated with inhalation, through
exposure to fumes as might occur with raku firing, or possibly
through exposure to very fine dust. The kind of granular manganese
that is used to produce speckles in clay or glaze seems unlikely to
be a problem. If anyone has solid evidence to the contrary, please
let me know.
Chris
Light One Candle Pottery
Fuquay-Varina, NC
candle@nuteknet.com
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The problem with granular manganese is that there are fine particles in among
the granules. If your suppliers really wanted to, they could get data on how
much is present and what size range they are in. Try asking for "particle
size distribution" data. The original manufacturers usually have this kind
of information for their industrial customers.
You also can use some common sense and observe the stuff visually, put some
in water and shake it up, etc., to see if you can detect the smaller
particles. These are the ones that mix with the clay dust and end up all
over the pottery.
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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