SCIENCE
Polinium Ploy (Part 2)
By Dr Rizwana Rahim
Chicago, IL
Polonium
(Po) is the first element discovered in 1899 by
Marie and Pierre Curie, both future Nobelists.
Po is a silvery metal (At. No. 84, At. Wt. 209),
readily soluble in dilute acids but only slightly
in alkalis. It is 2.5 x 10^11-times more toxic than
hydrogen cyanide. It is present in nature but in
extremely low abundance in the environment, including
as a contaminant in tobacco, in the soil (about
one-trillionth of a curie/g), in air (produced by
radon-22 gas decay) and in Uranium ores (about 1
mg/ton of Uranium-238 ore).
According to Argonne National Labs, Po has about
25 radioisotopes, more than any other element. Po-210
has a half-life of 138 days (i.e., it takes 138
days to reduce the original amount in half. Po-210
decays to lead (Pb) isotope-206, by the emission
of alpha particles. Exposure to it from external
sources can be easily blocked, but not when it is
within the body. One mg Po-210 emits as much alpha
particles as 5 g of Radium-226. Other radioisotopes
of Po with significant half-life include Po-208
and Po-209. Commercially, Po-210 (At. No. 84) is
not easy to produce. Very small quantities of it
are produced by neutron bombardment of Bismuth (Bi-209;
At. No. 83). Decay of Po-210 generates enormous
heat (one-half gram of it generating 900 degree
F or, 500 degree C) and for this reason it is used
a heat source in space satellites and lunar rovers
in cold lunar environs. It is also used in ceramic
micro-beads and chemical ionization devices as static
removers; production of DVD, computer chips, etc.,
all require static-free environments. If the microbeads
are accidentally ingested, the beads and thus the
radioactivity are not likely to remain in the body
for long.
210 Po-210 is very lethal, only if inhaled or ingested.
As it decays fairly rapidly (138, half-life), its
alpha radiation emissions cause enormous internal
damage. One gram of Po-210 can deliver up to 1 million
lethal doses. Since alpha particles strongly react
with matter, a thin film oil/liquid, or a layer
of dead skin cells on one’s body can be effective
protection against Alpha-emission. Because of this,
Henry Kelly (Federation of American Scientists)
says that, once produced and obtained, Po-210 can
be easily transported. But, without nuclear reactors,
it seems nearly impossible to produce Po-210. And,
to extract sufficient amount of Po-210 from static
removers and other Po-210 containing devices would
require buying excessive number of these devices,
which is not going to go unnoticed. For these reasons,
Steve Fetter of University of Maryland doesn’t
think Po-210 would be effective as a weapon of mass
destruction, and he offers this scenario: if a Po-210
device is dropped on a sidewalk, the contamination
will surely be great but no exposure problem “unless
you go lick the sidewalk.”
Once Po-210 is ingested, inhaled or absorbed by
the body otherwise, it is distributed widely via
blood, and the whole body would be exposed to the
damage it would cause. Through blood, spleen, liver
and kidney could each get 10% of the intake, the
rest (70%) distributed in the entire body. Alpha-particles
would destroy DNA, most cellular functions and eventually
the organs. About one-tenth of a microgram is considered
enough to kill a human being.
Al Keane, an Argonne biophysicist who specializes
in radiation-caused biological effects, thinks that
by scanning his body with gamma-ray detector, it
should be possible to work out the Po-210 dosage
Litvinenko had received. In addition to alpha-particles,
Po-210 also emits gamma rays (one gamma particle
per 100,000 alpha-particles). While alpha particles
in the body cannot be detected outside (alpha-emissions
cannot penetrate the skin), gamma rays CAN be detected,
which would help calculate how much Po-210 did Litvinenko
receive.
Though Po-210 was found on the surfaces of places
Litvinenko (and other-contaminated persons) visited,
P-210 exposure to anyone else would be negligible,
unless, e.g., Po-210 from their fingers which may
have touched a contaminated surface is transferred
to mouth or nose.
In addition, various rumors were circulating about
Litvinenko himself that: he was involved in blackmail
attempts, threatening to make public highly confidential
information he claimed he had from KGB files; he
was a supoorter/sympathizer of Chechen rebels and
was himself involved in making a dirty bomb; he
converted to Islam while he was bed-ridden (which
is why, before burial in Highgate Cemetery, some
people say, there was a memorial service for him
in a London mosque).
In any case, the face of a hair-less, totally emaciated
face of Livinenko on his deathbed has been etched
on our memory, and we wonder if the KGB of the Cold
War days has been resurrected as we go into 2007.
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