10.4122/1.1000001607 Larmet, H. Delolme, C. Bedell, J.-P. Neto, M. Facilitated transport of metals and bacteria into two infiltration basins in Lyon (France) under changing hydrological conditions: soil column study DTU Library, Technical University of Denmark (DTU) 2005 Heavy metals bacteria facilitated transfer infiltration basin Laboratoire des Sciences de l\342\200\231Environnement, Ecole Nationale des Travaux Publics de l\342\200\231Etat en Conference presentation 10.4122/1.1000001608 text/xml 1 The surface of infiltration basins, used to discharge urban stormwater, is an overpolluted matrix containing many reactive compounds liable to facilitate the transfer of heavy metals through the vadose zone to the aquifer. In the two basins studied, the metallic content is high (970 ppm of Zn and 5.23 ppm of Cd) and the organic matter and the bacteria are very abundant (5.56E+09 to 1.23E+10 bacteria/g of dry soil), by opposition to those of the unpolluted underlying soil ; the granulometric analysis also underscore the numerical importance of colloids and aggregates in the topsoils. Instability tests and leaching tests in small columns complete the study and the evaluation of potential behaviour of the surface soils and their components. Instability tests establish that Zn has big affinities with the organic matter and with the colloidal compartment, while Cd remains in the aggregates. In columns where rainfalls close to real hydrodynamic conditions are simulated, the first pore volume water eluted is distinguished by high contents on metals and bacteria, but the alternance of wetting/drying phases is attended to largely influence the fate of this two compartments. To complete ultra- and microfiltration, coupling MEB and X-fluorescence is foreseen to investigate their potential bonds.