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ScienceBlog
Scienceblog.org is our own portal for students and teachers. It brings all our latest articles, free images, newsfeeds, downloads, multimedia resources, and weblinks relevant for the study of  21st Century Science. This site is o­ne of  number of complementary websites we have developed for science education. All developed using wonderful Open Source software!

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spacer.gif   Polonium-210
Posted by: Admin on Tuesday, November 28, 2006 - 12:30 AM
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Radioactive materials What exactly is Polonium-210, and why is it so deadly?






Polonium-210 was allegedly used to murder Alexander Litvinenko, o­n November 23, 2006. According to Britain's Health Protection Agency, traces of polonium were found in his urine, as well as in several locations he had visited shortly before becoming ill. 


Polonium-210  is an isotope of  the element Polonium. Polonium has an  atomic number of 84. It contains 84 protons in its nucleus. Different isotopes contain different numbers of neutrons in the nucleus. Polonium-210 contains 126  neutrons. ( 210 - 84)

Polonium is a very scarce element, and is o­nly found in extremely small quantities in the Earth's crust. It was first discovered by Marie Curie in 1898. It is mainly used in industry to neutralise static electricity in certain manufacturing processes. Polonium-210 has also been used as a heat source to power thermoelectric cells in artificial satellites.

Polonium-210 emits high energy alpha particles. These alpha particles can cause intense ionisation. Outside the body, they are unable to penetrate the skin, and are easily absorbed by a thin sheet of a paper. This is because their energy is rapidly absorbed as a result of the high interactions with atoms. o­nce inside the body the the intense energy alpha particles can cause severe damage to cells and organs. Small amounts no larger that a few grains of salt can cause severe radiation sickness. Such is the intensity of the alpha particles, that o­nly 0.5 g of Polonium would be sufficient to raise its temperature by 500 degrees centigrade.

Polonium is extremely toxic.  Weight for weight, polonium is almost 250 billion times as toxic as hydrogen cyanide.

The half-life of radioactive element is the time it takes for the substance to reach o­ne-half of its intensity. This is the time it takes for half of the radioactive nuclei to decay (change into other elements). Polonium-210 has a half-life of 138.376 days. A short-half life is useful when the intensity is required to reduce to a virtually negligible amount after it has done its damage. The longer it remains, the less obvious its presence becomes, and more difficult to detect. O­nce inside the body the Biological or effective half-life needs to be considered. The Biological or effective half-life is the time required for the amount of a radionuclide deposited in a living organism to be diminished 50 percent as a  result of the combined action of radioactive decay and biological elimination.


 
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