Mauro,
What type of Cr isotope analysis are you looking for- what is your goal?

Presumably you are interested in mass-dependent fractionation (hence
the posting to this list).  If so, we can do some analyses here at
Univ. of Illinois (USA) or could consult with a laboratory in Europe
to get them done there.  I don't think anyone is running Cr stable
isotopes there yet.

There are no references yet, but we are about to submit a paper.  The
Cr isotope papers in the literature are all on radiogenic variations
in meteorites- these use a different analysis method, and all
terrestrial materials should be identical.

Our rather sparse data so far suggest that most industrial Cr starts
out unfractionated isotopically, relative to igneous rocks and Cr
ores.  It also looks like there is little fractionation in Cr plating
baths- surprising!

One concern is that distinguishing different Cr sources may be
complicated if the aquifer is not strongly oxidizing.  If dissolved
oxygen is low or zero, Cr(VI) reduction is likely and any
interpretation needs to consider the effects (enrichment of heavy
isotopes in the remaining Cr(VI)- we have measured this in the lab).

I'd be happy to help out if this looks promising to you.
Best,
Tom Johnson






>Dear all,
>
>1) I would like to find a laboratory in Europe where it is possible to run
>water samples for Cr isotopes, and to know the cost of the analysis
>
>2) I wonder if there is someone in the list who can suggest me some
>references regarding Cr isotopes as indicators of sources of chromium
>contamination
>
>thanks
>Mauro

--
**************************************
Thomas M. Johnson
Assistant Professor
Dept. of Geology
245 Natural History Bldg.
1301 W. Green St.
University of Illinois
Urbana, IL  61801
Phone (217) 244-2002
FAX  (217) 244-4996

Visit the Hydrogeology Program Web Site at
http://www.geology.uiuc.edu/~bethke/index.html
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