Monona Rossol on sun 21 dec 97
---------- Forwarded message ----------
Date: Fri, 19 Dec 1997 09:31:18 EST
From: Tom Buck
Subject: Re: lithium & strontium limits
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> How can one say what you do about Strontium Carbonate? Strontium
> compounds are widely used in medicines, eg, in a brand of toothpaste to
> counter sensitivity in tooth enamel. My reading of the literature leads me
> to say that Strontium ions, unlike Barium ions, are well tolerated by the
> body, and do not pose a hazard to potters who use SrCO3 in their glazes.
> This topic has been covered before, and Monona Rossol's texts go into
> detail.<
The man's right. Most strontium compounds are not very toxic. At very high
doses they'll make you sick--but you have to really chow it down. The only
chronic data in drinking water showed tooth defects in a child whose drinking
water contained a massive 13 mg/L. Sometimes people get confused between
regular strontium and Sr90, the radioactive isotope of strontium released by
some atomic reactions.
Strontium is deposited in bones and teeth similarly to calcium which is
probably why the radioactive isotope is so toxic. And it may be that its
similarity to calcium has something to do with the fact that combining
strontium with a cancer-causing anion seems to make it more toxic.
To illustrate: there are no occupational air quality standards for most
strontium compounds because they are of such low toxicity--except for one:
Strontium chromate. The chromate ion is a carcinogen. And strontium
chromate has one of the most restrictive standards ever set: 0.0005 mg/m3!
This was set after evaluating animal studies showing this compound to be one
of the most cancer-causing substances ever tested.
To me, all this is fascinating. Who'd think taking one of the least toxic
of the metals and combining it with cancer-causing chromate ion would make
the resulting compound more cancer-causing than other chromates?
Each metal has its own unique way of functioning, each compound has its own
story. I wrote a whole column on the unique problems with lithium which
should be out in Clay Times this month or next.
Monona
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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