Wednesday, November 6, 2013

Polonium Poisoning - A Primer

Now that it appears likely that Yasser Arafat was killed back in November 2004 by polonium poisoning, I wanted to do a brief posting on what happens when one ingests polonium (or Po-210) and how it is created.

Polonium, an element with atomic number 84, was discovered in 1898 by Pierre and Marie Curie and was named after Marie's native land of Poland.  It is produced during the decay of natural uranium-238 and can be produced during the chemical processing of uranium ores and is widely distributed throughout the earth's crust, albeit in very small quantities.  Po-210 can also be manufactured by irradiating bismuth-209, creating bismuth 210 which then decays into Po-210.  Only about 100 grams of polonium are produced every year, making it an extremely rare element. 

Polonium is used in devices that eliminate static electricity in machinery including paper rollers and synthetic fibre spinners.  Since polonium also emits so many alpha particles, a capsule containing about 1/2 gram will spontaneously reach a temperature of 500 degrees Celcius.  This makes polonium an ideal lightweight heat source for powering thermoelectric cells in satellites and was used on the Soviet moon rovers to keep their internal components warm.

Po-210 has a very short half life of only 138 days.  When it decays, polonium emits alpha particles only.  It is a very volatile element with 50 percent vaporizing in air over a 45 hour period.

Polonium is highly radioactive and very toxic.  Damage to humans occurs from the absorption of alpha particles into tissue.  Only a minute dose of 10 to 30 micrograms is considered fatal.  Polonium is only dangerous when ingested since alpha particles do not travel more than a few centimetres in air.  The alpha particles emitted by polonium can easily be stopped with a sheet of paper, clothing or human skin.  It can however, cause great damage when it is ingested through eating or drinking contaminated food or water, breathing air that is contaminated with polonium or through an open wound.

Once a human has ingested polonium, it concentrates in red blood cells, the liver, kidneys, spleen, bone marrow, gastrointestinal tract and gonads.  It is eliminated in urine, bile, sweat, breath and is also deposited in human hair.  Unabsorbed polonium is also eliminated in faeces.  Symptoms of poisoning include nausea, diarrhea, anorexia and lymphopenia (an abnormally low number of lymphocytes in the blood).  The higher the exposure level, the more rapid the onset of symptoms and the more rapid the decline in the level of lymphocytes.  Eventually, cardiovascular and central nervous system syndromes develop and hair loss occurs along with bone marrow failure.  Death occurs within weeks to months depending on the level of exposure and those who survive, often take months to recovery fully.

The use of polonium as a murder weapon was stimulated by the poisoning of Alexander Litvinenko, a former officer of the Russian FSB, in 2006.  In his case, Mr. Litvinenko died three weeks after drinking tea that was spiked with Po-210 with two former KGB colleagues at a hotel in London.  Here is a before and after photo of Mr. Litvinenko, showing the effects of Po-210 poisoning:

In the case of Mr. Arafat, at this point, it is not clear who or how the polonium was administered.  Tests of some of his belongings including a toothbrush and some garments show elevated levels of polonium.  Specimens taken from his decayed corpse after exhumation in 2012, including a tooth, fragments from the scalp and rib and pelvis bones showed that they "moderately support the proposition that death was the consequence of poisoning with polonium-2010.".  In the case of Mr. Arafat, he began to show signs of illness in Ramallah on October 12, 2004 that were consistent with polonium poisoning and died one month later on November 11, 2004.

What a horrible way to go. 

1 comment:

  1. Fascinating and timely. I guess it's the bullet of the 'elite' in today's world. Thanks.