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DBPottery

Trace amounts of toxic elements in materials

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Hello,

Some of the material analysis I received show trace amounts of a toxic material. I'll specifically point out lead. I only recall seeing it in the colorants, such as Cobalt (0.0002%) and Red Iron Oxide (30ppm). At such a small amount, is this something I should leach test for? I want to be on the safe side, but it just seems like an impurity than can be ignored.   Looking to see what is standard protocol for this situation. 

Thanks,

Daniel

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Don't worry about it. That amount of cobalt is infinitesimal and the iron isn't an issue at all. I'm not sure what you mean by:

On 10/3/2018 at 7:05 PM, DBPottery said:

I'll specifically point out lead.

 

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My opinion is that you shouldn't eat the material, but after it's fired into a glassy matrix I wouldn't worry too much about it.  The EPA has determined there is no safe level of lead exposure, so if you are feeling a bit paranoid you can test your fired body\glaze.  

In something like RIO, if it has 30ppm of lead, and let's say a gallon of glaze calls for 100 grams of RIO, you glaze a mug with it and it takes an ounce of glaze.  So at this point there is 1.28 grams of RIO on a mug, 1.28 grams times 30ppm is 0.00000384 grams of lead trapped in a glassy matrix.  

 

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3 minutes ago, Min said:

Don't worry about it. That amount of cobalt is infinitesimal and the iron isn't an issue at all. I'm not sure what you mean by:

 

Pretty sure he means contaminants in our materials we use to make glazes and clays (clays, oxides, etc)

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2 minutes ago, Min said:

Don't worry about it. That amount of cobalt is infinitesimal and the iron isn't an issue at all. I'm not sure what you mean by:

 

Sorry, I should have worded that better. The specific analysis just for the cobalt carbonate analysis shows lead in the amount of 0.0002% in the cobalt carbonate. The Red Iron Oxide analysis shows lead at 30ppm in the analysis of just the Red Iron oxide. I was trying to point out the amount of lead in each material. 

I know some toxic metals are just natural impurities, but wasn't sure at what point it needs tested for, as the main material is the core of the chemical makeup. 

Thank you,

Daniel

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On 10/13/2018 at 11:57 AM, Callie Beller Diesel said:

For practical purposes regarding functional work, it's far more useful to have the finished glaze tested rather than the raw ingredients. The raw ingredients only affect you, or anyone handling the raw glaze. 

I certainly agree testing the finished glaze is the best way to go. I just wasn't sure if at such a small amount that it can be considered an impurity and be ignored. Officially leach testing isn't exactly cheap.  Thanks.

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