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Relation of reactive solute-transport parameters to basic soil properties

Tijdschriftbijdrage - Tijdschriftartikel

Solute-transport parameters are needed to assess the pollution risks of soil and groundwater resources. A reliable estimate of these parameters from easily measurable soil properties is therefore important. So, the correlations of the transport parameters for one metalloid compound (NaAsO2), six heavy metal compounds (Cd(NO3)2, Pb(NO3)2, Ni(NO3)2, ZnCl2, CuSO4 and Co(NO3)2), two pesticides (cartap and carbendazim) and one inert salt (CaCl2) with some basic properties of eight agricultural soils of Bangladesh were investigated. The purpose of this study was to generate information for development of non-parametric pedo-transfer functions for reactive solute transport through soils. The transport experiments with the solutes were done in repacked soil columns under unsaturated steady-state water flow conditions. The major solute-transport parameters – velocity of transport (V), dispersion coefficient (D), dispersivity (), retardation factor (R) and Peclet number (P) – were determined by analysing solute breakthrough curves (BTCs). The basic soil properties pertinent to solute transport: clay content, median grain diameter (D50), pore-size distribution index (n), bulk density (), organic carbon content (C) and pH were determined. The associations of the solute-transport parameters with these soil properties were investigated and evaluated. Both the solute dispersivity and retardation factor increased significantly (p<0.05) ( linearly and R following power law) with the increase in soil clay content. Dispersivity significantly decreased with the increase in median grain diameter following power law. The V, D, and P values were weakly and negatively correlated with the soil bulk density. Retardation factor, R, was moderately and positively correlated with the ratio of clay content to organic carbon content. Dispersivity decreased but P increased, both significantly, with increasing pore-size distribution index, n. V, D and P were positively correlated with soil pH, while R and were negatively correlated with it. The correlation of the solute-transport parameters with soil properties being significant (p < 0.05), in most cases, provides strong possibility of predicting solute-transport parameters from the basic soil properties through the development of pedo-transfer functions.Keywords: Reactive solutes, transport parameters, soil pH, pore-size distribution.
Tijdschrift: Eurasian journal of soil science
Issue: 4
Volume: 7
Pagina's: 326 - 336
Jaar van publicatie:2018