Hello Michael,
we have been working on a map of lead isotopic signatures in the global
atmosphere for the past 4-5 years or so, which will be published shortly
(You and L. Kadanoga actually took valuable samples for us as well. Again,
thanks for that, I'll send reprints as soon as available!).
As leaded petrol is still a main source of atmospheric Pb in some countries,
we were interested in the Pb IC of TEL from the different suppliers in the
different countries. The Pb ores used in the production of TEL determine its
IC, however, different TEL production plants use Pb from a variety of ores
(whichever are the cheapest). Unless you know the relative amounts of Pb
ores used by a particular TEL producing plant it is difficult to know the
accurate IC of the TEL. (see for example: Veron A., Flament P., Bertho M.L.,
Alleman L., Flegal R. and Hamelin B. (1999b) Isotopic evidence of pollutant
lead sources in Northwestern France, Atmos. Environ. 33, 3377-3388.). The
source of TEL (i.e. the company or production plant), usually does not
change in a particular country (with some exceptions), however, the source
of Pb for the TEL production does.
We sent at least 25 letters to production plants and headquartes of major
TEL producers, refineries etc. and asked for information about the sources
of their Pb and TEL, respectively. That was a bit naive, I suppose, we did
not get a single reply!!
Temporal trends measured in aerosols during the time when leaded petrol was
still in use and the major source of atmospheric Pb contamination will give
you some information about the TEL composition and its change with time. Pb
isotope ratios in US aerosols and petrol have been evaluated for example by:
Rosman K.J.R., Chisholm W., Boutron C.F., Candelone J.P. and Hong S. (1994)
Isotopic evidence to account for changes in the concentration of lead in
Greenland snow between 1960 and 1988. Geochim. Cosmochim. Acta 58,
3265-3269. (and references therein)
Info for Canadian Pb IC in aerosols for example in:
Sturges W.T. and Barrie L.A. (1987) Lead 206/207 isotope ratios in the
atmosphere of North America: tracers of American and Canadian emissions.
Nature 329, 144 - 146.(and references therein)
Sturges W.T. and Barrie L.A. (1989) The use of stable lead 206/207 ratios
and elemental composition to discriminate the origins of lead in aerosols at
a rural site in Eastern Canada. Atmos. Environ. 23, 1645 - 1657.(and
references therein)
The people from the Centre de Recherche GEOTOP, at the Universty of Quebec,
Montreal (Simonetti and Gariepy et al.) might also be of help for getting an
accurate idea about the Pb IC of Canadian aerosols and petrol in the past.
Ethyl Co. has a production plant in Sarnia, Ontario, Canada. Maybe they can
provide information about the sources of TEL and Pb for the production in
Canada in the past. However, based on our experience, I doubt it.
I hope I could help a bit,
Cheers
Andreas
________________________________________________________________________
Dr. Andreas Bollhoefer
Centre on Excellence in Mass Spectrometry
Department of Applied Physics Phone: + 61 8 9266 7314
Curtin University of Technology Fax: + 61 8 9266 2377 (w)
Email:[log in to unmask] or + 61 8 9388 0739 (hm)
GPO Box U 1987, Perth 6845
Western Australia
Western Australian Isotope Science Research Centre
http://www.curtin.edu.au/curtin/centre/waisrc/
http://staff.curtin.edu.au/~rbollhoe/andreas.html
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