|
Written by Dr David Sowby
|
|
Monday, 15 January 2007 |
In his review of 'Blowing Up Russia' by Alexander Litvinenko and Yuri
Felshtinsky (Irish Independent, January 6) Myles McWeeney refers to
Litvinenko's excruciating death from radioactive poisoning. The poison
used was the radioactive nuclide polonium-210 (Po-210). This nuclide is
found in nature - for example, in the Irish Sea and in tobacco - since
it is derived from the decay of uranium, radium and radon.
In this form it is exceedingly dilute, and could not possibly poison
anyone. However, it can also be produced in highly concentrated form in
a nuclear reactor by bombarding bismuth-210 with neutrons. It is used
in industry and as a static eliminator. It also has military uses. It
is likely that it was reactor-induced Po-210 that was responsible for
Litvinenko's death.
In its concentrated form Po-210 is lethal in exceptionally small
amounts. Various estimates have been made of the actual amount of the
nuclide needed to kill someone; such estimates show that a very small
amount - less than a microgram - would kill an average person. A
microgram - one millionth of a gram - is of course an unbelievably tiny
quantity, which shows why it is so potent and dangerous.
After ingestion of several micrograms of Po-210, gastrointestinal symptoms begin to appear within a day or so.
These symptoms will mimic food poisoning-nausea, diarrhoea, vomiting,
and general tiredness. At this stage it is therefore unlikely that
polonium poisoning will be suspected. This is followed by a "latent"
phase and then a further decline, including the loss of all hair,
massive depletion in white blood cells and bone marrow depression.
Polonium-210 in someone's body is not detectable with a standard
radiation instrument used outside the body, which again explains why it
isn't likely to be detected in the early phase. Testing the
individual's urine or faeces for alpha radiation is the method of
detection, but would probably be started only at a late stage, after
irreparable damage has been done.
A median survival time of twenty days has been associated with a dose
of about 0.01 microgram of polonium-210 per kilogram of body weight.
For a 70-kilogram person, this would mean that a lethal dose could be
delivered by the ingestion of only about 0.7 microgram of Po-210.
|
|
Last Updated ( Thursday, 01 February 2007 )
|
