Hello all,
   A group here at the University of Arizona studying plant water use is
interested in feeding trees water that has been labeled in deuterium. Due
to the large quantities of water involved and cost/delivery considerations
we will be mixing D2O with local waters to create our labeled water supply.
In light of the discussions on isogeochem last year, I am concerned about
the residence time of D2O molecules in the resulting water supply. D2O
seems to create problems in measuring the HD ratio of the water due to the
production of greater than normal amounts of D2 molecule (mass 4). We are
analysing waters using the reduction method (using U, Zn, or Cr in various
labs here).
   Does anyone have thoughts on how long the mixed waters should sit around
before use in order to allow H2O + D2O to go to 2HDO? What is the rate of
diffusion / exchange? Is there a catalyst we could use to speed this up (if
it is slow)?

Many thanks for your help.
- David Dettman



At 06:32 PM 6/10/98 -0400, you wrote:
>>Dear List:
>>
>>        I'd appreciate some description [or reference] to how your
>>laboratories handle BaCO3/BaSO4 slurries for 13C analysis of DIC in ground
>>water *after* they are received by you.
>>
>>
>>********************************
>>Steve Nelson
>
>
>Hassan, A. A., 1982, Methodologies for extraction of
>dissolved inorganic carbon for stable carbon isotope
>studies:  Evaluation and alternatives:  U.S.
>Geological Survey Water-Resources Investigations 82-6,
>51 p.
>
>Gleason, J. D., Friedman, I., and Hanshaw, B. B.,
>1969, Extraction of dissolved carbonate species from
>natural water for carbon-isotope analysis:  U.S.
>Geological Survey Prof. Paper 650-D, p. D248-D250.
>
               David Dettman          [log in to unmask]
               Dept. of Geosciences   ph. (520) 621-4618
               Univ. of Arizona       FAX (520) 621-2672
               Gould-Simpson Bldg.
               Tucson, AZ 85721