Polonium is a radioactive material which can be traced from very small quantities in the environment. It is about 5.000 times more radioactive than radium, however its abundance is only about 0.2% of that of radium. It can be isolated from pitchblende, a brownish-black mineral. It was the first of two elements found by Marie Curie; alongside radium, in pitchblende residues, at an early stage of research into radioactive materials. Her subsequent death from leukaemia is assocated with her handling of radioactive materials, and exposure to large doses of radiation. Subsequent to Marie Curie''s pioneering work it has proved possible to separate small quanities of polonium from other elements.
Applications for polonium, include as a rather expensive heat source in satellites.