I don't know much either but I read that as well. It sounds like barium sulfate is relatively stable in the blood and water. However, I wonder if the pH of the uterus can make it break down into its ionic components more readily. My doctor is suspecting some kind of heavy metal toxicity. I'm not ruling out Mirena at the moment (I had terrible uterine and vaginal cramping with a sensitive cervix at the same time as the start of tingling. the cramping ceased with removal of mirena), but I am checking all the chemicals in my lab right now!!