Effects of Past Copper Contamination and Soil Structure on Copper Leaching from Soil
- Marcos Paradelo *ad,
- Per Moldrupb,
- Emmanuel Arthura,
- Muhammad Naveeda,
- Martin Holmstrupc,
- Jose E. López-Periagod and
- Lis W. de Jongea
- a Dep. of Agroecology, Faculty of Science and Technology, Aarhus Univ., Blichers Allé 20, P.O. Box 50, DK-8830 Tjele, Denmark
d Soil Science and Agricultural Chemistry Group, Dep. of Plant Biology and Soil Science, Faculty of Sciences, Univ. of Vigo, E-32004 Ourense, Spain
b Dep. of Civil Engineering, Aalborg Univ., Sohngaardsholmsvej 57, DK-9000 Aalborg, Denmark
c Dep. of Bioscience, Aarhus Univ., Vejlsøvej 25, DK-8600 Silkeborg, Denmark
Copper contamination affects biological, chemical, and physical soil properties and associated ecological functions. Changes in soil pore organization as a result of Cu contamination can dramatically affect flow and contaminant transport in polluted soils. This study assessed the influence of soil structure on the movement of water and Cu in a long-term polluted soil. Undisturbed soil cores collected along a Cu gradient (from about 20 to about 3800 mg Cu kg−1 soil) were scanned using X-ray computed tomography (CT). Leaching experiments were performed to analyze tracer transport, colloid leaching, and dissolved organic carbon (DOC) and Cu losses. The 5% arrival time (t0.05) and apparent dispersivity (λapp) for tracer breakthrough were calculated by fitting the experimental data to a nonparametric, double-lognormal probability density function. Soil bulk density, which did not follow the Cu gradient, was the main driver of preferential flow, while macroporosity determined by X-ray CT (for pores >180 μm) proved the best predictor of solute transport. Higher preferential flow due to the presence of well-aligned pores and small cracks controlled water movement in compacted soil. Transport of Cu was rapid during the first flush (≈1 pore volume) in association with the movement of colloid particles, followed by slower transport in association with the movement of DOC in the soil solution. The relative amount of Cu released was strongly correlated with macroporosity as determined by X-ray CT, indicating the promising potential of this visualization technique for predicting contaminant transport through soil.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © 2013. . Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.