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Effect of artificial root exudates on the sorption of phenanthrene in soils |
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Abstract The sorption of phenanthrene by three soils with addition of artificial root exudate (ARE) was investigated using a batch experimental method. Phenanthrene sorption isotherms by soils could be significantly described by a liner sorption model irrespective of the addition of ARE. The distribution coefficients (Kd) and the organic carbon-normalized distribution coefficients (Koc) for phenanthrene sorption were significantly lower when ARE present in soils, and Kd and Koc values tended to decrease with increasing the concentrations of ARE in soils. The concentrations of dissolved organic matter (DOM) in equilibrium solution for phenanthrene sorption were detected, and DOM concentrations were higher with the addition of ARE. While the soil organic carbon content was observed to be a little lower with the ARE addition. The combination of DOM and phenanthrene in solution was proposed to dominate the decrease of phenanthrene sorption in soils with the addition of ARE. Results of this work indicated that root exudate clearly inhibited the sorption of PAHs, and thus could enhance their availability in soil environment.
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Received: 05 June 2009
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