J. Phys. IV France 7 (1997) C2-831-C2-832
XAFS Characterization of Copper Contamination in the Unsaturated and Saturated Zones of a Soil ProfileD.E. Sayers1, D. Hesterberg2, W. Zhou1, W.P. Robarge2 and G.M. Plurnmer1
1 Department of Physics, Box 7518, North Carolina State University, Raleigh NC 27695, U.S.A.
2 Department of Soil Science, Box 7619, North Carolina State University, Raleigh NC 27695, U.S.A.
The fate of heavy-metal contaminants in the environment, and the design and success of remediation strategies at hazardous waste sites depend on the chemical speciation of the contaminants. The objective of this study was to determine the molecular-scale chemical form (species) of heavy metals in different zones of a contaminated soil having a shallow ground water table. Copper in the unsaturated surface horizon and the water-saturated and partially-saturated subsurface horizons of a disturbed soil from the lower eastern coastal plain of North Carolina was characterized using XAFS spectroscopy. Extended x-ray absorption fine structure (EXAFS) and x-ray absorption near edge structure (XANES) data showed that the dominant form of Cu(II) bonding ranged from Cu-S in the deeper soil zones to Cu-O in the shallowest zone. The results suggest that the surface and subsurface horizons will respond differently to remediation treatments.
© EDP Sciences 1997