Re: uranium [234] reported in drinking water-Another possibility

[RadiumProj@cs.com]

In a message dated 10/10/00 4:15:54 PM Eastern Daylight Time, 
bobshann@home.com writes:

> > I recall, that U-238 and U-234 activity concentrations are usually equal.
>  I
>  > can hardly imagine any process that would disturb equilibrium when
>  leaching
>  > the isotopes from the ground rock or soil.
>  >
>  
>  U-238/U-234 disequilibrium is very commonly observed  in groundwaters. The
>  phenomenon is reportedly responsible for U-234:U-238 activity ratios as 
high
>  as 10:1.
====
Another possibility on the higher than expected U-234/U-238 ratio reported in 
this well water sample. Has anyone measured Ra-226 specifically by some  
technique specific to Ra-226??

Radsafe:

Is it possible that this sample of  water contains very, very elevated levels 
of Ra-226  [in complete non-equilibruium with its parent U-238 due to the 
difference in mobility and solubility] such that the 4.784 Mev alpha of 
Ra-226 [94% abundance] is being mistaken for the 4.776 MeV alpha from U-234. 
Knowing nothing about the alpha spec system involved, its resolution, or the 
method for resolving alpha spectra it is hard to say whether this is truly a 
possibility. I know levels of Ra-226 above 15 or so pCi/l in natural ground 
waters, in the absence of some local source of contamination, are very rare 
but they do occur. 

Stewart Farber
email: radiumproj@cs.com
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