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Re: How much plutonium?????




On Mon, 8 May 2000, Cathy Lee wrote:

> I recently read that half a kilo of plutonium
> could induce lung cancer in everyone on the planet.
> 
> I was wondering if any of you could tell me about the
> scientific merits of this claim.

	--A typical estimate is that one lung cancer may be caused by each
0.000200 grams of plutonium inhaled by people (the easiest available
reference for me is  my paper in Health Physics 32:359; 1977, but later
papers give similar results). The number of cases that may be caused by
1/2 kilo = 230 grams is thus 230 / 0.000200 = 1,150,000; this is only a
tiny fraction of the population of the Earth. Of course a much more
relevant question is how this plutonium can be inhaled by people. As a
practical illustration, if it is dispersed in the center of a large city
in the most effective way for causing harm, my paper calculates that there
would be 27 eventual deaths.
	Note that 10,000 pounds of plutonium has been dispersed into the
atmosphere by bomb tests. This is millions of times more than is ever
expected to be released by the nuclear power industry. 

> Also, has anyone actually calculated the number of radio
> active decays in the body, say, per second. I would
> be interested to know!

	--Our bodies are struck by about 15,000 gamma rays every second
from natural sources. About 20% of these come from radioactive decays
inside our bodies. The rest are from cosmic rays, radioactivity in the
ground and in building materials, etc.

> Bernard L. Cohen
Physics Dept.
University of Pittsburgh
Pittsburgh, PA 15260
Tel: (412)624-9245
Fax: (412)624-9163
e-mail: blc+@pitt.edu


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