Hello... Polonium is toxic, chemical symbol (Po), atomic number 89, and it is highly toxic and extremely radioactive. Of course, its rays outside the human body are short and cannot cause significant harm to the human body. , but if it is inhaled, ingested, or enters the body through body wounds, it will be very dangerous. Polonium less than the size of a grain of salt can poison a 70-kilogram person... It was Marie Curie in 1898 What she and her husband discovered...