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Modeling Transport of a Degradable Chemical and Its Metabolites in the Unsaturated Zone
Author(s) -
Tim Udoyara S.,
Mostaghimi Saied
Publication year - 1989
Publication title -
groundwater
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.84
H-Index - 94
eISSN - 1745-6584
pISSN - 0017-467X
DOI - 10.1111/j.1745-6584.1989.tb00481.x
Subject(s) - freundlich equation , aldicarb , laplace transform , chemistry , sorption , isotropy , adsorption , soil science , environmental chemistry , environmental science , pesticide , mathematics , organic chemistry , mathematical analysis , physics , quantum mechanics , agronomy , biology
A mathematical model for transport and transformation of a pesticide and its metabolites in the soil is presented. Mechanisms for convective‐transport, hydrodynamic dispersion, ionic exchange, biological degradation, and hydrolysis are accounted for in the mathematical formulation. The major assumptions used in developing the model include: flow in the soil is in the vertical direction and one‐ dimensional, soil system is homogeneous and isotropic, volumetric water content and Darcy's flux are constant in time and space, and a linear reversible Freundlich isotherm describes the concentrations in the aqueous and adsorbed phases. Based on the outlined assumptions and Laplace transform techniques, analytical solutions for the concentrations of the parent material and its metabolites are presented. The applicability and potential of the model are demonstrated by predicting the transport and transformation of aldicarb (a nematicide of agricultural significance) and its metabolite, aldicarb sulfoxide, in the soil.