Explainer: What is polonium?
Background on the rare and highly radioactive substance found in Yasser Arafat’s final personal belongings.
What is polonium?
Polonium is a rare and highly radioactive element. It is found naturally in the atmosphere and in the earth’s crust, though in miniscule quantities. Marie Curie discovered the element in the late 19th century and named it after her native country of Poland (in Latin: Polonia).
It has dozens of isotopes. One of the most common is polonium-210, which emits highly radioactive alpha particles; this was the isotope found on Yasser Arafat’s personal effects during Al Jazeera’s initial investigation.
Because of its radioactivity, polonium has been used as a trigger for nuclear weapons, and as a power source for satellites and other spacecraft. The Russian space programme used it to heat rovers that landed on the Moon in the 1970s.
A lethal dose of polonium 210 can be caused by ingesting just 50 nanograms or inhaling an even smaller amout of 10 nanograms, which means that only one gram of polonium 210 could in theory poison and kill about 10 million people.
Has it been used as a poison before?
Yes, at least once. Polonium was used to kill Alexander Litvinenko, a onetime Russian spy turned dissident.
Litvinenko was in good health until November 1, 2006, when he suddenly became sick and was hospitalised. He initially suffered from severe diarrhoea and vomiting; the hospital diagnosed him with a stomach infection.
His condition continued to worsen, though. Doctors discovered that his white blood cell count had plummeted, making him susceptible to infection.
“His skin had turned yellow, indicating liver dysfunction, and he was tested for the two most likely causes, hepatitis and AIDS, but neither was the case,” John Emsley wrote in Molecules of Murder, which includes a chapter on polonium poisoning. “Then his hair began to fall out.”
Doctors eventually decided that Litvinenko was suffering from radiation poisoning, and further tests identified polonium as the culprit.
Polonium is also believed to have killed several other people, including Curie’s daughter Irene, and two people working on Israel’s nuclear programme.
What are the symptoms of polonium poisoning?
Because there have been so few recorded cases, there is not much scientific literature on the subject.
The handful of human cases, as well as animal studies, suggest symptoms similar to other forms of radiation poisoning – vomiting, diarrhoea, hair loss, a low white blood cell count. Traces of the poison reach vital organs like the liver and heart, and cause those organs to fail.
How is polonium produced?
It occurs naturally in uranium ores, but at extremely small concentrations, as low as 100 micrograms per tonne of ore.
Rather than laboriously extracting it from uranium, modern-day manufacturers create polonium in nuclear reactors, by bombarding bismuth with neutrons. Most of the world’s polonium supply is produced in Russia.