Re: Los Alamos - Airborne activity from wildfires

[Michael McNaughton <mcnaught@lanl.gov>]

At 08:10 AM 5/12/00 -0500, Stewart Farber wrote:
>a nationwide survey of Cs-137 in domestic fireplace woodash which I
conducted in
>1990-91 showed Cs-137 levels as high as 20,000 pCi/kg ash. I recollect the
airborne 
>ash fraction can range from 2 to 5% of the total mass of  biomass being
burned. 

During the wildfire at Los Alamos we did not observe airborne Cs-137 above
the MDA, which is ~2 fCi/m3, e.g., see:
http://www.air-quality.lanl.gov/NewData/G/Open_CerroGrandeFire_1Page2.html

Is this because most Cs-137 remains in the ash?

Similarly, we don't see airborne K-40; however, the measurements are not as
sensitive, i.e., the MDA for K-40 is larger, ~30 fCi/m3.

Some elements are easily volatilized, e.g., Po, Bi, Pb. Others are not,
e.g., U, Sr, K, Cs. I am not sure about Be. I suppose this depends on the
chemistry, e.g., KCO3 is stable at quite high temperatures. But the
references I have been able to find are mixed.

Can anyone recommend a good reference on this subject?

For a summary on the references I have found so far, see:
http://www.air-quality.lanl.gov/CerroGrandeFireRadioSource.pdf

Thanks, mike
Mike McNaughton
email: mcnaught@LANL.gov or mcnaughton@LANL.gov
phone: (505)667-6130
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