Marie Curie was present in such minute quantities that they would eventually have to process tons of the ore. In July 1898, Curie and her husband published a joint paper announcing the existence of an element which they named "polonium", in honour of her native Poland, which would for another twenty years remain partitioned among three empires (Russian, Austrian, and Prussian). On 26 December 1898, the Curies announced the existence of a second element, which they named "radium", from the Latin word for "ray". In the course of their research, they also coined the word "radioactivity". To prove their discoveries beyond any
Polonium sulfur, also in group 16 of the periodic table, in sulfur-containing amino-acids or related molecules and that similar patterns of distribution occur in human tissues. Polonium is indeed an element naturally present in all humans, contributing appreciably to natural background dose, with wide geographical and cultural variations, and particularly high levels in arctic residents, for example. Polonium-210 in tobacco contributes to many of the cases of lung cancer worldwide. Most of this polonium is derived from lead-210 deposited on tobacco leaves from the atmosphere; the lead-210 is a product of radon-222 gas, much of which appears to originate from the