De. Sayers et al., XAFS CHARACTERIZATION OF COPPER CONTAMINATION IN THE UNSATURATED AND SATURATED ZONES OF A SOIL-PROFILE, Journal de physique. IV, 7(C2), 1997, pp. 831-832
The fate of heavy-metal contaminants in the environment, and the desig
n and success of remediation strategies at hazardous waste sites depen
d on the chemical speciation of the contaminants. The objective of thi
s study was to determine the molecular-scale chemical form (species) o
f heavy metals in different zones of a contaminated soil having a shal
low ground water table. Copper in the unsaturated surface horizon and
the water-saturated and partially-saturated subsurface horizons of a d
isturbed soil from the lower eastern coastal plain of North Carolina w
as characterized using XAFS spectroscopy. Extended x-ray absorption fi
ne 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 s
uggest that the surface and subsurface horizons will respond different
ly to remediation treatments.