TJR Posted November 16, 2014 Report Share Posted November 16, 2014 I have come across a great turquoise glaze recipe for cone 10 reduction. I know it uses quite a high percentage of barium carbonate. What exactly is the health concern with barium and food? What ratio of strontium can I use as a substitute for said barium? How do we know if strontium is safe for food vessels? Link to comment Share on other sites More sharing options...
Callie Beller Diesel Posted November 16, 2014 Report Share Posted November 16, 2014 As summary of safety info from Difitalfire says a) It's pretty susceptible to acid leaching, it's pretty toxic at low doses and c) screws with your heart muscles and digestive tract first, and heavy exposure can further mess with your kidneys as your body tries to eliminate it. Having said that, it takes the ingestion of 1-15 g of it to do serious acute harm, a situation that would only occur if someone was taking it on purpose, or if there was food contamination involved. It's biological half life in the body (the amount of time it takes for the "dose" to be metabolized to half of the starting amount) is between 2 and 20 hours. So from this information, it's most toxic to the potter who is mixing and applying the glaze, but due to its solubility, if used as a liner in a coffee cup, the glaze will discolour. From personal experience, it'll be kinda soft and easily scratched. But really pretty. Link to comment Share on other sites More sharing options...
Guest JBaymore Posted November 16, 2014 Report Share Posted November 16, 2014 FYI........ at NCECA last year... it was mentioned in a session on leaching that strontium was actually of more concern to the presenter than barium, since lab testing shows it leaches more easily than barium. The biggest hazard is to the potter. That is why most schools don't use it anymore. BTW....... it is one of the active ingredients in rat poisons. LD50 for BC is 200 mg/kg [Mouse]. 418 mg/kg [Rat]. That is 0.418 grams per kilogram of weight. For an adult human (assuming the science holds at the rat dosage) at 72 Kilos, that is 30 grams ingested. (Weigh that amount out to see what that means.) LD 50 means that will KILL 50% of the entities exposed to that amount. So yes, you'd have to screw up royally to get that kind of acute dose. You should read all of this: http://www.sciencelab.com/msds.php?msdsId=9927090 best, ........................john Link to comment Share on other sites More sharing options...
Callie Beller Diesel Posted November 16, 2014 Report Share Posted November 16, 2014 I should add that the above information is based on a healthy adult male. Anyone on, say, heart meds or who is smaller, or immune-compromised could have other issues. Link to comment Share on other sites More sharing options...
Pres Posted November 17, 2014 Report Share Posted November 17, 2014 Science department removed it from their shelves in the 80's, we followed. I was told by them that it could be absorbed through the skin, inhaled in very fine particles, and was bad ingested in even small amounts. After considerable reading I did realize that the most danger was to the potter. In my case to me and my students. I believed that the benefits were outweighed by the hazards, so no barium. Link to comment Share on other sites More sharing options...
Mark C. Posted November 17, 2014 Report Share Posted November 17, 2014 strontium will change the color as well.There was a good piece on this in last months CM. Mark Link to comment Share on other sites More sharing options...
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