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monona on dioxin (fwd)

updated wed 18 oct 00


Elke Blodgett on mon 16 oct 00

>From Monona Rossol

---------- Forwarded message ----------
Date: Mon, 16 Oct 2000 20:13:12 EDT
Subject: Re: dioxin (fwd)

> Date: Sun, 15 Oct 2000 08:52:20 -0400
> From: Nancy Galland
> Reply-To: Ceramic Arts Discussion List
> Subject: dioxin
> I am disturbed that Clayarters have not taken seriously the news that
> dioxin has been found in Ball Clay from mines in Mississippi, Kentucky, and
> Tennessee. Except for Edouard Bastarache's entries, no significant
> discussion has developed.

> We need answers to many questions, but how the dioxin got into the Ball
> clay is not a helpful one at this point.
> * We need to know if a substitute can be found for Ball Clay - I was told
> that it could , by technicians at the Laguna clay factory. We need to let
> them know we want it to be done. <

Dioxins have been found in a number of other mined minerals now. Dioxin has
been found in montmorillonite, bentonite, lime, and other clays and minerals.
We first need to find out how often dioxins and dibenzofurans occur in
minerals naturally, in which ones and how much. Otherwise we will be
substituting one dioxin contaminated material for another.

> * We need to know if dioxin remains in the clay after firing, and if so,
> can it leach through glazes. Do glazes and slips containing Ball Clay leach
> dioxins? <

I can't imagine that they would not burn off.

> * We need to know what happens to the dioxin in clay and glazes when we
> fire it - does it burn out, does it emit toxic fumes ? <

Dioxin contaminated clay and even uncontaminated clay will emit toxic stuff.
But kilns should be vented anyway. This sure makes one hell of another good
argument for installing ventilation!

> * It is esablished that dioxin enters the body through any path available:
> breathing dust and fumes, skin contact, ingestion. How can we protect
> ourselves from exposre? <

We probably can only reduce exposure. The first thing, as I said, is to get
EPA and FDA to do more testing to find out which minerals and clays are
dioxin free or low dioxin. The FDA already has got a list of anti-caking
clays and minerals that are dioxin free for manufacturers of animal feeds to
use. Perhaps a group like Clayart should contact FDA and ask for this list
of minerals and see if some will work for us, too.

If you are interested, you might want to contact Judy Gushee, Center for
Veterinary Medicine (HFV-230), Food and Drug Administration, 7500 Standish
Place, Rockville MD 20855, 301/827-0150 ( As you
probably can tell from the small number of comments I make on Clayart, I
don't have the time I used to have to follow these things up. I'm just
swamped with work.

Skin contact cannot really be avoided in pottery, but we sure can use good
methods to keep from snorting the dust.
> I have changed my clays to only those not containing ball clays. I suggest
> calling your suppliers and finding out which clays do not contain ball clay
> and changing to those until more answers are found and a substitute for
> the ball clay is found. <

Remember "ball clay" is just a method of mining--not a mineral class. Ball
clay can be many different clay minerals.

Monona Rossol
181 Thompson St., #23
NYC NY 10012-2586 212/777-0062

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