Numéro |
J. Phys. IV France
Volume 107, May 2003
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|
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Page(s) | 899 - 902 | |
DOI | https://doi.org/10.1051/jp4:20030443 |
J. Phys. IV France 107 (2003) 899
DOI: 10.1051/jp4:20030443
Trace metals dynamics in surface sediments investigated by DGT micro-scale measurements
M. Motelica-Heino1 and W. Davison21 BRGM, 3 avenue Claude Guillemin, 45060 Orléans cedex 2, France
2 Institute of Environmental and Natural Sciences, Lancaster University, Lancaster LA1 4YQ, U.K.
Abstract
In surface sediments, metal mobility is controlled by the recruitment and turn-over
of organic matter whereas sulphide is thought to control the concentration of metals in
sediment pore water by removing them from the solution. DGT is a dynamic probe that
measures the kinetically available fraction of metals or sulphide. DGT uses a credit card
size probe inserted into the sediment that provides a snapshot of the metal distribution in the
sediment, which can be uncovered by spectrochemical analytical techniques. In-situ vertical
profiles and horizontal maps of trace metals at high (mm scale) and ultra-high resolution
(100
m) together with Fe, Mn and sulphide were generated from DGT probes deployed in
surface sediments. Collectively, the results showed that besides vertical gradients, associated
with the depletion of oxygen with depth and the degradation of organic matter by a
succession of electron acceptors, small scale remobilisation of metals associated with
sediment heterogeneity take place.
© EDP Sciences 2003