U-234 environmental mobility

["Andrew Karam" <akaram@safety.rochester.edu>]

The earlier question made me go back to my isotope geology text.  I can add
a little to what I noted before.

- U-234:U238 ratios have been noted from unity to 10 or more in natural waters
- This effect was first explained in the early 1960s (references available
on request)
- The effect is attributed to a combination of damage to the crystal
structure, alpha recoil, and the fact that the radioactive decays may leave
U-234 in a more-soluble +6 oxidation state
- In addition, the intermediate progeny nuclides may be ejected or leached
from the mineral crystals (and, remember, clays are crystals, too),
subsequently decaying to U-234

A more detailed explanation can be found in "Radiogenic Isotope Geology" by
Alan Dicken or in "Principles of Isotope Geology" by Gunter Faure.  I'd be
happy to supply more reference information if asked to do so.

Andy

Andrew Karam, MS, CHP				
RSO, University of Rochester			  
(716) 275-3781 (voice)						
(716) 256-0365 (fax)
akaram@safety.rochester.edu

"The mind is not a vessel to be filled  but a fire to be lighted" 
 Plutarch