10.4122/1.1000001608
Larmet, H.
H.
Larmet
Delolme, C.
C.
Delolme
Bedell, J.-P.
J.-P.
Bedell
Neto, M.
M.
Neto
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
Conference full text
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
Ecole Nationale Des Travaux Publics De L\342\200\231Etat
Laboratoire Des Sciences De L\342\200\231Environnement
2005
en
10.4122/1.1000001607
application/pdf
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.