title: Modeling the migration of fallout radionuclides in soil using a transfer function model.
abstract: A stochastic model for transport of radionuclides in soil is presented. It is based on probability density functions of solute displacements, which are interpreted as impulse response functions of a linear dynamic system. Two transport models are discussed: (1) a convective-stochastic approach which takes into account spatial variability of flow and sorption and leads to a lognormal probability distribution of displacements, and (2) the conventional convective-dispersive model with a constant retardation coefficient. To compare their applicability, both models were applied to depth distributions of 90Sr and 137Cs fallout measured in an Orthic Podsol. The convective-stochastic approach was found to provide a better representation of the observed depth distributions. Using this model, migration rates of the radionuclides were calculated.
authors.affiliation: University of Bremen, FB 1, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Kirchner
mesh_terms: D008962:Models, Theoretical; D009689:Nuclear Warfare; D011338:Probability Theory; D011847:Radioactive Fallout / Q000032:analysis*; D012987:Soil / Q000032:analysis*; D012990:Soil Pollutants, Radioactive / Q000032:analysis*
chemical_list: D011847:Radioactive Fallout; D012987:Soil; D012990:Soil Pollutants, Radioactive