J. Phys. IV France
Volume 107, May 2003
Page(s) 695 - 698

J. Phys. IV France
107 (2003) 695
DOI: 10.1051/jp4:20030398

Speciation and mobility of Zn, Cu and Pb in a truck farming soil contaminated by sewage irrigation

T. Kirpichtchikova1, 2, A. Manceau1, B. Lanson1, M.A. Marcus3 and T. Jacquet2

1  Environmental Geochemistry Group, LGIT, Université J. Fourier, CNRS, BP. 53, 38041 Grenoble cedex 9, France
2  Site et Concept, 16 rue Jules Vallées, 75011 Paris, France
3  Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, U.S.A.


The forrns and mobility of Cu (290 mg/kg), Zn (1103 mg/kg), and Pb (535 mg/kg) in a soil used for intensive truck farining from the Region Ile-de-France, and which has been irrigated for more than a century with sewage water ftom the city of Paris, have been studied by chemical treatments and advanced x-ray techniques. Elemental associations and forms of metals were determined qualitatively and quantitatively by a combination of physical techniques, including  $\mu$PIXE (Cu, Zn, Pb), $\mu$SXRF (Cu, Zn), $\mu$EXAFS (Zn) and powder EXAFS (Zn). The nature, number, and relative proportion of Zn species were obtained by principal component analysis and decomposition of Zn K-edge EXAFS spectra. These data collectively indicate that Cu is associated mainly with organic matter, and that Zn and Pb are bound essentially to mineral constituents. Four Zn-containing species were positively identified: Zn-phosphate and phyllosilicate as dominant species, and Zn-Fe oxyhydroxide and willemite (Zn 2SiO 4) as minor species. Studies are underway to determine the structural forms of Cu and Pb. Depending on the chemical treatment, up to 70% Cu, ~50% Zn, and ~85% Pb can be removed in a few days with citrate and EDTA. Citrate is generally at least as efficient as EDTA, and it has the advantage ofbeing easily biodegradable and, hence, less harmful to ecosystems.

© EDP Sciences 2003