title: Formulation of a soil-pesticide transport model based on a compartmental approach.
abstract: A semianalytical soil-pesticide transport model is formulated based on a compartmental approach to determine spatial and temporal variations of pesticide residues across a soil profile. The compartmental model is implemented by drawing an analogy between a series of continuous-flow stirred tank reactors and a soil horizon that consists of multiple perfectly mixed compartments. The analogy is strengthened by exploiting a relation between the compartment series and the conventional convective-dispersive equation (CDE) for vertical transport in the soil. Consequently, the number of compartments in the model formulation is not free, but dictated as a function of transport parameters. The model formulation allows consideration of arbitrary boundary value specifications and also, for some cases, spatially varying initial concentration profiles. Sorption kinetics is represented via a two-site model that involves a linear sorption isotherm and a first-order irreversible sorption or a radial diffusive penetrating model. For these three cases, analysis of the compartmental model allows the resultant concentration profiles to be expressed in terms of the Poisson distribution. When a nonlinear kinetic sorption model is used to simulate the sorption processes, an analytical solution is not found and a numerical approach is required.
authors.affiliation: Department of Civil and Environmental Engineering, University of California, Davis 95616, USA. hbasagaoglu@ucdavis.edu
authors.forename: Hakan
authors.initials: H
authors.lastname: Başağaoğlu
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Ginn
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: McCoy
mesh_terms: D001280:Atrazine; D003198:Computer Simulation; D006540:Herbicides; D008962:Models, Theoretical; D016012:Poisson Distribution; D012989:Soil Pollutants
chemical_list: D006540:Herbicides; D012989:Soil Pollutants; D001280:Atrazine