描述
Thorium is a naturally occurring radioactive chemical element with the symbol Th and atomic number 90. It was discovered in 1828 by the Swedish chemist Jons Jakob Berzelius and named after Thor, the Norse god of thunder. In nature, virtually all thorium is found as thorium-232, which undergoes alpha decay with a half-life of about 14.05 billion years. The element has no known biological role. [Wikipedia]. Thorium is found in many foods, some of which are cashew nut, almond, black walnut, and butternut.