[ RadSafe ] Robots scour sea for atomic wasteSubmarines search for radioactive material dumped off the Scottish coast in the 1980s

[Bernard L. Cohen]

    According to my paper on "Hazards from Plutonium Toxicity" (Health 
Physics 32:359-379;1977) LD-50 for ingesting reactor plutonium in 
soluble form is 0.7 grams, and in insoluble form is 2.0 grams. If the 
material is not dissolved in the ocean water, it is presumably 
insoluble. So presumably, a "speck" is something more than 2.0 grams. 
Pure Pu-239 is seven times less dangerous than reactor plutonium 
(because of the Pu-238 in the latter) so a "speck" of Pu-239 would weigh 
about 14 grams, about one cubic centimeter in volume..
    LD-50 for ingestion of some other commonly available materials are: 
selenium oxide (used extensively in electronic devices) -0.3 grams, 
mercury dichloride (formerly widely used for soaking fingers or toes to 
draw out infections) - 0.8 grams, and caffeine (which all of us 
frequently ingest) - 14 grams.
    Basically, plutonium is dangerous only if inhaled as a very fine dust..


Steven Dapra wrote:
> May 25
>
>         This article was written by the "science editor."  I didn't 
> know "one speck" of plutonium was "capable" of killing me if I 
> swallowed it.  Goodness.  Life is full of surprises, isn't it?  Is a 
> speck one of the International Units?  How many specks are there in a 
> gram, or is it vice versa?
>
> Steven Dapra
>
>
>
> At 09:54 AM 5/25/08 +0100, Fred Dawson wrote:
>> Guardian Reports:-
>>
>> Robot submarines are to be used to sweep particles of plutonium and 
>> other
>> radioactive materials from the seabed near one of Britain's biggest 
>> nuclear
>> plants in one of the most delicate clean-up operations ever in this 
>> country.
>>
>> Each submersible will be fitted with a Geiger counter and will 
>> crisscross
>> the sea floor to pinpoint every deadly speck close to Dounreay on 
>> Scotland's
>> north coast before lifting each particle and returning it to land for 
>> safe
>> storage.
>>
>> Two kilometres of beach outside the Dounreay nuclear plant have been 
>> closed
>> since 1983, and fishing banned, when it was found old fuel rod fragments
>> were being accidentally pumped into the sea. The cause was traced and
>> corrected but particles - including plutonium specks, each capable of
>> killing a person if swallowed - are still being washed on to this 
>> bleakly
>> beautiful stretch of sand and cliff on mainland Britain's northern edge.
>>
>> Full report
>>
>> http://www.guardian.co.uk/environment/2008/may/25/pollution.conservation
>>
>> fwp_dawson at hotmail.com
>
>
>
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-- 
Bernard L. Cohen
Physics Dept., University of Pittsburgh
Pittsburgh, PA 15260
Tel: (412)624-9245  Fax: (412)624-9163
e-mail: blc at pitt.edu  web site: http://www.phyast.pitt.edu/~blc