
TY  - JOUR
A1  - Thayalakumaran, T. 
A1  - Vogeler, I. 
A1  - Scotter, D. R. 
A1  - Percival, H. J. 
A1  - Robinson, B. H. 
A1  - Clothier, B. E. 
T1  - Leaching of copper from contaminated soil following the application of EDTA. I. Repacked soil experiments and a model
JF  - Soil Research
JO  - Soil Res.
Y1  - 2003
VL  - 41
IS  - 2
SP  - 323
EP  - 333
KW  - iron, convection&#8211;dispersion equation, heavy metals.
UR  - https://doi.org/10.1071/SR02059 
N2  - The EDTA-enhanced remediation of copper contaminated sandy-loam soil of volcanic origin was investigated. The soil, from an orchard, was contaminated with about 250 mg/kg of copper due to the extensive use of copper sprays. Copper-contaminated soil was packed into 100-mm-long columns, and solutions of Na2H2EDTA with CaCl2, raised to a pH of 6.2, were applied at a flow rate of 24 mm/h. Application of an excess of 0.01 M EDTA leached about half the acid-extractable copper from the soil; most of it coming out in the first 3 liquid-filled pore volumes (PV). Also a 0.5 PV pulse of 0.001 M EDTA was applied to similar soil columns and then either leached immediately with 0.005 M CaCl2, or left for periods of up to 1 month before leaching. With immediate leaching, 70% of the EDTA applied was complexed with copper in the leachate, but after a month&#39;s delay only 24% was complexed with copper in the leachate, the rest being complexed with iron. There was no evidence of EDTA retardation or adsorption. The experimental results were simulated using the convection&#8211;dispersion equation, incorporating a source/sink term. This described the competing time-dependent reactions of copper and iron with EDTA, and the reversion of CuEDTA2&#8211; to adsorbed Cu2+ and Fe(III)EDTA&#8211; in solution. Reasonable simulations were achieved, mostly within errors of observation. 
ER  -

