• Media type: E-Article
  • Title: CHROMATOGRAPHIC TRANSPORT THROUGH SOILS: III. A SIMULATION MODEL FOR THE EVALUATION OF THE APPARENT DIFFUSION COEFFICIENT IN UNDISTURBED SOILS WITH TRITIATED WATER
  • Contributor: FRISSEL, M. J.; POELSTRA, P.; REINIGER, P.
  • Published: Martinus Nijhoff, 1970
  • Published in: Plant and Soil, 33 (1970) 1, Seite 161-176
  • Language: English
  • ISSN: 0032-079X; 1573-5036
  • Origination:
  • Footnote:
  • Description: A simulation model, written in CSMP, is described permitting the calculation of Chromatographie transport in heterogeneous systems like soils. Breakthrough curves of tritiated water were determined on undisturbed, water-unsaturated soil columns (100 cm length, 12 cm ø). With the model, tortuosity and dispersion factors were calculated for three soils — a sand, a clay and a loess. The mean values for the tortuosity were 0.3, 0.2, and 0.2 and for the dispersion 0.7, 0.8, and 6 cm, for the three soils respectively. From these values it appears that usually dispersion is the main factor in forming the distribution pattern in soil, the contribution of ionic diffusion being rather small. In many cases good approximative values of the dispersion coefficient may be obtained with an analytical solution of the chromatography equation assuming an averaged homogeneous system.