Polonium was discovered in 1898 by the scientists Marie Curie and Pierre Curie. It is a rare, unstable, highly radioactive element found in uranium ore. In terms of equivalent mass, polonium is around 250,000 times more toxic than hydrogen cyanide – and there is no antidote.
Polonium was discovered by the Curies while they were investigating the cause of pitchblende radioactivity. Pitchblende, a mineral comprised mainly of oxides of uranium, after removing its radioactive elements uranium and thorium, appeared more radioactive than both the uranium and thorium put together. The Curies investigated the cause and first separated out polonium in July 1898. Five months later they also isolated radium.
First called “Radium F”, polonium was named after Poland, the country where Marie Curie (photo left) was born. At that time her country was subject to Russian, German, and Austro-Hungarian partition and did not exist independently. It was Marie Curie’s hope that naming the element after her homeland would highlight the politics involved.
Polonium’s danger lies in its intense radioactivity, making it very difficult to deal with safely. Even handling tiny amounts requires specialized equipment and strict monitoring procedures to avoid contamination. Alpha particles emitted by polonium will damage organic tissue if ingested, inhaled, or absorbed, although they do not penetrate the skin and are not hazardous as long as they remain outside the body.
In the United States, polonium was produced as part of the Manhattan Project during World War II. It was a critical part of the implosion-type nuclear weapon used in the bombing of Nagasaki in 1945 in which 70,000 people died instantly and more than 50,000 die later from radiation sickness.
The presence of polonium in tobacco smoke has been known since the early 1960s. For over 40 years the world’s biggest tobacco companies secretly researched ways to remove it but without success and never publishing the results.
Polonium as an assassin’s weapon hit the headlines in 2006 when Russian dissident Alexander Litvinenko died in London. According to at least one environmental toxicologist and radiation expert, Litvinenko died of the acute radiation effects of polonium. Others point out that a coroner has yet to rule that polonium was the actual cause of Litvinenko’s death or indeed that he was murdered. Now, the body of the former Palestinian leader Yasser Arafat is being tested for polonium.
It has been suggested that the French scientist Irène Joliot-Curie, daughter of Marie and Pierre Curie died from the effects of polonium radiation. She was accidentally exposed to the element in 1946 when a sealed capsule exploded on her laboratory bench. She died of leukemia in 1956.
Some families seem to specialize in Nobel Prizes. In 1903 Pierre and Marie Curie received the Nobel Prize for Physics. In 1911 Marie Curie received the Nobel Prize for Chemistry. In 1935 their daughter Irène Joliot-Curie and her husband Frédéric Joliot-Curie received the Nobel Prize for Chemistry. And in 1965, Henry Labouisse, Director of UNICEF and the husband of the Curies’ second daughter Ève, won the Nobel Prize for Peace.
And Poland? It won brief independence in between 1918 and 1939 before being taken over by Nazi Germany and the Soviet Union. In 1945, betrayed by the Allies, it became a satellite of the USSR and in 1952 the People’s Republic of Poland. Only in 1989 did the country regain its independence. And in 2011, to mark the centenary of Marie Curie’s second Nobel Prize, an allegorical mural was painted on the façade of her Warsaw birthplace. It depicts the infant Marie holding a test tube from which emanate the dangerous elements that she would discover as an adult: radium and polonium.