Numéro J. Phys. IV France Volume 107, May 2003 381 - 384 http://dx.doi.org/10.1051/jp4:20030321

J. Phys. IV France
107 (2003) 381
DOI: 10.1051/jp4:20030321

## Speciation of lead in contaminated soil under the influence of plants and phosphate amendment type

C. Diyab1, F. Juillot2, C. Dumat1, G. Morin2, M. Benedetti3 and A. Mariotti1

1  LBI, Laboratoire de Biogéochimie Isotopique, UMR 7618 du CNRS, INRA-Paris 6, 4 place Jussieu, Tour 26 4$\rm ^e$ Étage Case 120, 75252 Paris cedex 05, France
2  LMCP, UMR 7590 du CNRS, Paris 6 & 7, IPGP, France
3  LGM, UMR 7047 du CNRS, Paris 6, France

Abstract

The toxicity of an element and its behaviour depend on its chemical form (speciation) and concentration. The objective of our work is to study the speciation of Pb under the influence of phosphate amendments (solide, soluble) and type of plants: peas, tomato (pH variation, organic acid complexes formation) in a polluted soil near one of Europe's largest lead contaminated area in the north of France. Chemical and physical methods were used to determine the speciation of lead in rhizospheric soil (chemical extraction, FX, EXAFS, SEM.). The formation of lead phosphate complexe was confirmed in rhizospheric soil of both plants. Quantity and chemical structure of phosphate lead complexe formed in soil, varied with the type of plante and phosphate amendement added. Analysis of organic acids secreted by the two plantes were performed to understand the effect of organic acids on the speciation of lead in the rhizospheric soil.

© EDP Sciences 2003