HR: 1330h
AN: H22A-0911    [PDF]
TI: Accelerated simulation of the migration of solutes in sandy soils amended by sewage sludge: Transport and retardation
AU: * Etchebers, o
EM: olivier.etchbers@univ-pu.fr
AF: Laboratory Hydro Geochemistry and Environment, Dept Earth Sciences, Univ. of Pau, BP 1155, Pau Cedex, 64013 France
AU: Kedziorek, M A
EM: monika.kedziorek@univ-pau.fr
AF: Laboratory Hydro Geochemistry and Environment, Dept Earth Sciences, Univ. of Pau, BP 1155, Pau Cedex, 64013 France
AU: Chossat, J
EM: jean-claude.chossat@cemagref.fr
AF: CEMAGREF-Bordeaux, 50 Avenue de Verdun, Gazinet Cedex, 33611 France
AU: Riou, C
EM: claude.rulliere@cea.fr
AF: CEA-CESTA, BP 2, Le Barp, 33114 France
AU: Bourg, A C
EM: alain.bourg@univ-pau.fr
AF: Laboratory Hydro Geochemistry and Environment, Dept Earth Sciences, Univ. of Pau, BP 1155, Pau Cedex, 64013 France
AB: A common way to dispose of sewage sludge is to spead it on agricultural land because of its high nutrient (P, N) and org C contents. However, in addition to these beneficial components, sewage sludge can contain toxic chemicals such as heavy metals. This farming technique is relatively recent (several decades, at most) and there is still a need for information concerning the processes controlling the fate of the heavy metals in the sludge. To study how fast they migrate in the soil profile, the transfer of water and associated solutes in both unsaturated and unsaturated conditions can be accelerated by centrifugation according to the equation: tsimulated = treal * g2. (t: time). In a lysimeter study (diameter 30 cm, depth 60 cm) carried out using the CEA-CESTA Silat 265 centrifuge, we simulated, at 20 g, several months of percolation in one day. Experiments were done on cores of sandy forest soil (podzol) to which various sewage sludges (containing 2 to 12 mg/kg Cd, 20 to 120 mg/kg Ni, 50 to 465 mg/kg Pb) and simulated rain were applied. Major ions migrated at an estimated rate of 6-8.5 mm/simulated day (2-3 m/simulated year), while heavy metals (Cd, Ni, Pb) were retarded by a factor of 1.5 to 2. The retention of these heavy metals is associated with the organic C content of the soil profile (rich in the upper horizon).
DE: 1803 Anthropogenic effects
DE: 1806 Chemistry of fresh water
DE: 1831 Groundwater quality
DE: 1875 Unsaturated zone
DE: 1894 Instruments and techniques
SC: Hydrology [H]
MN: 2003 Fall Meeting