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Short-term natural attenuation of copper in soils: Effects of time, temperature, and soil characteristics

Authors

  • Yibing Ma,

    Corresponding author
    1. Land and Water, Commonwealth Scientific and Industrial Research Organisation, Private Mail Bag 2, Glen Osmond, SA 5064, Australia
    2. Institute of Soil and Fertilizers, Chinese Academy of Agricultural Sciences, Beijing 100081, China
    • Land and Water, Commonwealth Scientific and Industrial Research Organisation, Private Mail Bag 2, Glen Osmond, SA 5064, Australia
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  • Enzo Lombi,

    1. Land and Water, Commonwealth Scientific and Industrial Research Organisation, Private Mail Bag 2, Glen Osmond, SA 5064, Australia
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  • Annette L. Nolan,

    1. Land and Water, Commonwealth Scientific and Industrial Research Organisation, Private Mail Bag 2, Glen Osmond, SA 5064, Australia
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  • Mike J. McLaughlin

    1. Land and Water, Commonwealth Scientific and Industrial Research Organisation, Private Mail Bag 2, Glen Osmond, SA 5064, Australia
    2. Department of Soil and Land Systems, School of Earth and Environmental Sciences, The University of Adelaide, Private Mail Bag 1, Glen Osmond, SA 5064, Australia
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  • Presented at the Symposium on Risk Assessment of Metals in Soils, 14th Annual Meeting, SETAC Europe Meeting, Prague, Czech Republic, April 18–22, 2004.

Abstract

Natural attenuation of metals added to soils refers to the processes by which the mobility and bioavailability/toxicity of the added metals decline with time. In this paper, we used isotopic dilution techniques to investigate the short-term (30 d) natural attenuation of Cu added to 19 European soils at two effective concentrations shown to inhibit plant (tomato) growth by 10 and 90%. The results showed that the lability of Cu added to soils rapidly decreased after addition, especially in the soils with pH > 6.0, followed by a slow decrease in Cu lability. The lability of Cu added to soils also decreased with increasing incubation temperature. The activation energies and the apparent diffusion rate coefficients for the attenuation processes were 33 to 36 kJ/mol and 0.66 to 20.9 × 10−10/s at 20°C, respectively, and were consistent with Cu diffusion in meso- and micropores. The attenuation of Cu lability was modeled on the basis of three processes: precipitation/nucleation of Cu on soil surfaces, Cu occlusion within organic matter, and diffusion of Cu into micropores. The soil and environmental factors governing attenuation rates were soil pH, organic matter content, incubation time, and temperature. Soil pH is the key factor for natural attenuation of Cu added to soils. The model can be used to scale ecotoxicological data generated from different soils and under different incubation times and temperatures.

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