Kinetic extractions to assess mobilization of Zn, Pb, Cu, and Cd in a metal-contaminated soil: EDTA vs. citrate.
Kinetic EDTA and citrate extractions were used to mimic metal mobilization in a soil contaminated by metallurgical fallout. Modeling of metal removal rates vs. time distinguished two metal pools: readily labile (QM1) and less labile (QM2). In citrate extractions, total extractability (QM1+QM2) of Zn and Cd was proportionally higher than for Pb and Cu. Proportions of Pb and Cu extracted with EDTA were three times higher than when using citrate. We observed similar QM1/QM2 ratios for Zn and Cu regardless of the extractant, suggesting comparable binding energies to soil constituents. However, for Pb and Cd, more heterogeneous binding energies were hypothesized to explain different kinetic extraction behaviors. Proportions of citrate-labile metals were found consistent with their short-term, in-situ mobility assessed in the studied soil, i.e., metal amount released in the soil solution or extracted by cultivated plants. Kinetic EDTA extractions were hypothesized to be more predictive for long-term metal migration with depth.
Labanowski
Jérôme
J
INRA, UR 251 Unité PESSAC, RD 10, F-78026 Versailles Cedex, France.
Monna
Fabrice
F
Bermond
Alain
A
Cambier
Philippe
P
Fernandez
Christelle
C
Lamy
Isabelle
I
van Oort
Folkert
F
D002104:Cadmium; D002614:Chelating Agents / Q000737:chemistry; D019343:Citric Acid / Q000737:chemistry; D003300:Copper; D004492:Edetic Acid / Q000737:chemistry; D052918:Environmental Restoration and Remediation / Q000379:methods*; D007220:Industrial Waste; D007854:Lead; D019216:Metals, Heavy / Q000737:chemistry; D012989:Soil Pollutants / Q000737:chemistry; D015032:Zinc
D002614:Chelating Agents; D007220:Industrial Waste; D019216:Metals, Heavy; D012989:Soil Pollutants; D002104:Cadmium; D019343:Citric Acid; D007854:Lead; D003300:Copper; D004492:Edetic Acid; D015032:Zinc