New Pot! Duan Ni or not?

[entropyembrace]

Like many other things you need a little bit to live, but too much can kill you.

I think the readers here need to get a feeling of how much exactly " a little bit" you meant here. Are we talking about gram, milligram, parts per million?
Perhaps you can elaborate more so they get the right picture.

Iron you need 8-28mg a day. Over 800mg can be toxic though it would take 4000+mg to be lethal without medical attention.

Manganese you need 1.8 to 2.8mg a day. Ingested manganese rarely causes health problems because excess manganese isn't absorbed through the intestine. Manganese dust is very toxic when inhaled and can cause nervous system damage because it freely crosses into the blood through lung tissue.

Cobalt animals can't synthesize into Vitamin B12 ourselves so we have to get it in the form of Vitamin B12 in our diets since we don't have big fermentation chambers in our guts where bacteria can synthesize Vitamin B12 for us. Cobalt poisoning from ingestion is rare. Doses around 20g of soluble cobalt can be lethal. Most cobalt poisoning cases come from damaged hip replacements which are made of cobalt or inhaled cobalt dust in industrial settings.

Chromium (III) is pretty much non-toxic because its excluded from entering your cells. Chromium (VI) is toxic and can cause genetic damage, so even small doses should probably be avoided. Chromium oxide is the Chromium (III) ion.

Exact numbers for toxic doses are hard to find because it's not easy to measure and define exactly what the toxic threshold is but hopefully that helps. I tried to pull some estimates of doses which can cause illness or be deadly from various medical sources.

Since fired ceramics are glassy and mostly inert it's highly unlikely that you're ingesting any significant part of your teapot. Tea pots don't dissolve into our tea...otherwise they would get lighter as we use them and need to be replaced frequently!

Besides that these compounds aren't very dangerous when ingested (and yes you can eat clay, kaolinite clays are used to treat diarrhea even in western medicine. You're not grinding up and snorting your teapot, that's what you would have to do to get sick from the metal oxides in the clay.

Most metal poisoning from pottery comes from glazes or overglaze painting which is less stable than a fired clay body and can contain more dangerous metals like lead and cadmium if they were not intended for use with food to produce bright colours.

[chrl42]

Iron you need 8-28mg a day. Over 800mg can be toxic though it would take 4000+mg to be lethal without medical attention.

Manganese you need 1.8 to 2.8mg a day. Ingested manganese rarely causes health problems because excess manganese isn't absorbed through the intestine. Manganese dust is very toxic when inhaled and can cause nervous system damage because it freely crosses into the blood through lung tissue.

Cobalt animals can't synthesize into Vitamin B12 ourselves so we have to get it in the form of Vitamin B12 in our diets since we don't have big fermentation chambers in our guts where bacteria can synthesize Vitamin B12 for us. Cobalt poisoning from ingestion is rare. Doses around 20g of soluble cobalt can be lethal. Most cobalt poisoning cases come from damaged hip replacements which are made of cobalt or inhaled cobalt dust in industrial settings.

Chromium (III) is pretty much non-toxic because its excluded from entering your cells. Chromium (VI) is toxic and can cause genetic damage, so even small doses should probably be avoided. Chromium oxide is the Chromium (III) ion.

Exact numbers for toxic doses are hard to find because it's not easy to measure and define exactly what the toxic threshold is but hopefully that helps. I tried to pull some estimates of doses which can cause illness or be deadly from various medical sources.

Since fired ceramics are glassy and mostly inert it's highly unlikely that you're ingesting any significant part of your teapot. Tea pots don't dissolve into our tea...otherwise they would get lighter as we use them and need to be replaced frequently!

Besides that these compounds aren't very dangerous when ingested (and yes you can eat clay, kaolinite clays are used to treat diarrhea even in western medicine. You're not grinding up and snorting your teapot, that's what you would have to do to get sick from the metal oxides in the clay.

Most metal poisoning from pottery comes from glazes or overglaze painting which is less stable than a fired clay body and can contain more dangerous metals like lead and cadmium if they were not intended for use with food to produce bright colours.

Very thanks for your devoted knowledge.

I've also wondered whether firing can hinder the dangerous materials of clay or not. And many collectors believe 'high firing' (as crystallization) can do for less. Nowadays really tons of cheap colorful teawares are on the market...but almost no one worries, that's due to a belief these glazes as being a shield that makes the questionable materials intact from going to our lips.

I mentioned some 3~4 years ago about this belief on this forum...and supposedly professional potter here said there is no data that firing can do such functions.


And being glassy contributes to the crystallization of clay, but most of Yixing teapots are not crystallized to full. They are not ceramics. They need to be fired in 1300c to be crystallized but no one do that unless they fire 'Yaobian' pots. Furthermore, crystallized pots are not porous that can be treated as a demerit.

[kyarazen]

there's a strange blatant reluctance of some to acknowledge that there's no chemical difference between iron oxides detected in antique clay, ancient clay, old clay, rocks, versus that of a big bag that comes out of a chemical factory, if the factory, be it european, mainland or not, can produce it to a high purity.

i have an atomic spectro at my work place and there are people routinely collecting data on metals. there's just no spectral differences from iron leached into the water supply from iron pipings, and that of iron from sigma aldrich or merck. ignorance at its best? antiquewares and old wares contribute to some kind of self actualization?

on the point of teapot "dissolving", its pretty interesting to see that Hojo's talking about all the leaching minerals from his pots, and at least for his clays, i.e. nosaka (sado style zhuni), it does leach, but not incredibly large amounts. the pot was originally iron 3 red but some parts of it is becoming iron (2) grey/black after i had been putting it through rounds of green pu-erh and dousing tea on the exterior during brewing like i do with yixing. perhaps in due time the pot may "thin" but in a very long time due to the slow kinetics. glass is an amorphous substance, semi-solid-liquid anyway, so perhaps by that time too the tea pot would be out of shape too

leaving nutrigenomics aside, where people in future can be assessed genetically on how well they metabolize, excrete different substances, the usually recommended daily levels are just a guideline, with significantly less concern on ions that are usually excretable by the body, excess iron can be gotten rid of, etc. the worst is still lead, mercury, arsenic. recently there was a small issue in taiwan where a collector was "recalling" some of the cups he had sold, and also informing the general public after lead had been found in the white glaze in those "internal white glazed" external purple clay type of tea cups from the 50s and earlier. lead was doped in the glaze to enable them to aid the firing process and reduce failure. such toxic ions are slow poisons, you dont die from it, but perhaps your neurons (such as those in the brain and perhaps some the peripheral nervous system) that dont regenerate much will be subject to such slow poisoning. muscle weakness is one, neurodegeneration is another. but to some, if life's too short, and they dont mind making it shorter, then anything goes!

Like many other things you need a little bit to live, but too much can kill you.

I think the readers here need to get a feeling of how much exactly " a little bit" you meant here. Are we talking about gram, milligram, parts per million?
Perhaps you can elaborate more so they get the right picture.

Iron you need 8-28mg a day. Over 800mg can be toxic though it would take 4000+mg to be lethal without medical attention.

Manganese you need 1.8 to 2.8mg a day. Ingested manganese rarely causes health problems because excess manganese isn't absorbed through the intestine. Manganese dust is very toxic when inhaled and can cause nervous system damage because it freely crosses into the blood through lung tissue.

Cobalt animals can't synthesize into Vitamin B12 ourselves so we have to get it in the form of Vitamin B12 in our diets since we don't have big fermentation chambers in our guts where bacteria can synthesize Vitamin B12 for us. Cobalt poisoning from ingestion is rare. Doses around 20g of soluble cobalt can be lethal. Most cobalt poisoning cases come from damaged hip replacements which are made of cobalt or inhaled cobalt dust in industrial settings.

Chromium (III) is pretty much non-toxic because its excluded from entering your cells. Chromium (VI) is toxic and can cause genetic damage, so even small doses should probably be avoided. Chromium oxide is the Chromium (III) ion.

Exact numbers for toxic doses are hard to find because it's not easy to measure and define exactly what the toxic threshold is but hopefully that helps. I tried to pull some estimates of doses which can cause illness or be deadly from various medical sources.

Since fired ceramics are glassy and mostly inert it's highly unlikely that you're ingesting any significant part of your teapot. Tea pots don't dissolve into our tea...otherwise they would get lighter as we use them and need to be replaced frequently!

Besides that these compounds aren't very dangerous when ingested (and yes you can eat clay, kaolinite clays are used to treat diarrhea even in western medicine. You're not grinding up and snorting your teapot, that's what you would have to do to get sick from the metal oxides in the clay.

Most metal poisoning from pottery comes from glazes or overglaze painting which is less stable than a fired clay body and can contain more dangerous metals like lead and cadmium if they were not intended for use with food to produce bright colours.

[betta]

Iron you need 8-28mg a day. Over 800mg can be toxic though it would take 4000+mg to be lethal without medical attention.

Manganese you need 1.8 to 2.8mg a day. Ingested manganese rarely causes health problems because excess manganese isn't absorbed through the intestine. Manganese dust is very toxic when inhaled and can cause nervous system damage because it freely crosses into the blood through lung tissue.

Cobalt animals can't synthesize into Vitamin B12 ourselves so we have to get it in the form of Vitamin B12 in our diets since we don't have big fermentation chambers in our guts where bacteria can synthesize Vitamin B12 for us. Cobalt poisoning from ingestion is rare. Doses around 20g of soluble cobalt can be lethal. Most cobalt poisoning cases come from damaged hip replacements which are made of cobalt or inhaled cobalt dust in industrial settings.

Chromium (III) is pretty much non-toxic because its excluded from entering your cells. Chromium (VI) is toxic and can cause genetic damage, so even small doses should probably be avoided. Chromium oxide is the Chromium (III) ion.

Exact numbers for toxic doses are hard to find because it's not easy to measure and define exactly what the toxic threshold is but hopefully that helps. I tried to pull some estimates of doses which can cause illness or be deadly from various medical sources.

Since fired ceramics are glassy and mostly inert it's highly unlikely that you're ingesting any significant part of your teapot. Tea pots don't dissolve into our tea...otherwise they would get lighter as we use them and need to be replaced frequently!

Besides that these compounds aren't very dangerous when ingested (and yes you can eat clay, kaolinite clays are used to treat diarrhea even in western medicine. You're not grinding up and snorting your teapot, that's what you would have to do to get sick from the metal oxides in the clay.

Most metal poisoning from pottery comes from glazes or overglaze painting which is less stable than a fired clay body and can contain more dangerous metals like lead and cadmium if they were not intended for use with food to produce bright colours.

Thank you for the information, entropyembrace.
What kind of metal contaminant is of a concern when we're talking about clay and soil?
Are there any benefit of ingesting or contact with Arsen, Cadmium, Lead, Mercury, Vanadium?

[entropyembrace]

Thank you for the information, entropyembrace.
What kind of metal contaminant is of a concern when we're talking about clay and soil?
Are there any benefit of ingesting or contact with Arsen, Cadmium, Lead, Mercury, Vanadium?

No for all but Vanadium, those are much more toxic than the metals I talked about above. Even ingesting small quantities can harm you.

As far as I know they're not used in clay but Cadmium, Lead, and Vanadium are in some glazes.

Vanadium is required and its absorption in the digestive tract is regulated, but it's extremely toxic when inhaled. I don't think there are any guidelines for supplementation of vanadium in humans (though apparently body builders sometimes use it) but lab animals on highly controlled diets sometimes need vanadium supplementation to grow properly.

[betta]

No for all but Vanadium, those are much more toxic than the metals I talked about above. Even ingesting small quantities can harm you.

As far as I know they're not used in clay but Cadmium, Lead, and Vanadium are in some glazes.

Vanadium is required and its absorption in the digestive tract is regulated, but it's extremely toxic when inhaled. I don't think there are any guidelines for supplementation of vanadium in humans (though apparently body builders sometimes use it) but lab animals on highly controlled diets sometimes need vanadium supplementation to grow properly.

It's very informative, thank you.
We live in an area which used to be a coal mining region.
The mining activities were stopped more than 5-6 decades ago.
Toxic metal / compound such as mercury, lead, arsen, cadmium, vanadium and nickel are found in the rock formation at a significant concentration.
Interestingly they are also found at high concentration at the neighbouring region (hundreds of km away) where no coal was found.

Geologist indicates that one can really have "the luck" to buy a farming land where the geological formation beneath contains high amount of toxic metal. No one knows until he/she really checks it.