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Please use this identifier to cite or link to this item: http://hdl.handle.net/10373/148

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Title: Continuous time random walk model better describes the tailing of atrazine transport in soil
Authors: Deng, J. C.
Jiang, X.
Zhang, Xiaoxian
Hu, W.
Crawford, John W.
Affiliation: University of Abertay Dundee. Scottish Informatics, Mathematics, Biology and Statistics Centre
Keywords: Atrazine
Soil columns
Issue Date: May-2008
Publisher: Elsevier
Type: Article
Refereed: peer-reviewed
Rights: Published version is Crown copyright (c)2008, published by Elsevier Ltd available from http://www.sciencedirect.com
Citation: Deng, J.C. et al. 2008. Continuous time random walk model better describes the tailing of atrazine transport in soil. Chemosphere. 71(11): pp.2150-2157. [online]. Available from doi:10.1016/j.chemosphere.2008.01.001
Abstract: Contaminant transport in soils is complicated and involves some physical and chemical nonequilibrium processes. In this research, the soil column displacement experiments of Cl‾ and atrazine under different flow velocities were carried out. The data sets of Cl‾ transport in sandy loam fitted to the convection dispersion equation (CDE) and the two-region model (TRM) indicated that the effects of physical nonequilibrium process produced by immobile water on the breakthrough curves (BTCs) of Cl‾ and atrazine transport through the repacking soil columns were negligible. The two-site model (TSM) and the continuous time random walk (CTRW) were also used to fit atrazine transport behavior at the flow rate of 19.86 cm hˉ¹. The CTRW convincingly captured the full evolution of atrazine BTC in the soil column, especially for the part of long tailing. However, the TSM failed to characterize the tailing of atrazine BTC in the soil column. The calculated fraction of equilibrium sorption sites, F, ranging from 0.78 to 0.80 for all flow rates suggested the contribution of nonequilibrium sorption sites to the asymmetry of atrazine BTCs. Furthermore, the data sets for the flow rates of 6.68 cm hˉ¹ and 32.81 cm hˉ¹ were predicted by the TSM and the CTRW. As to the flow rate of 6.68 cm hˉ¹, the CTRW predicted the entire BTC of atrazine transport better than the TSM did. For the flow rate of 32.81 cm hˉ¹, the CTRW characterized the late part of the tail better, while the TSM failed to predict the tailings of atrazine BTC.
URI: http://hdl.handle.net/10373/141
ISSN: 0045-6535
Appears in Collections:SIMBIOS Collection

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