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Modeling and experimental validation of volatile organic contaminant diffusion through an unsaturated soil
Author(s) -
Arands R.,
Lam T.,
Massry I.,
Berler D. H.,
Muzzio F. J.,
Kosson D. S.
Publication year - 1997
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/96wr03976
Subject(s) - loam , flux (metallurgy) , soil science , diffusion , environmental science , desorption , silt , soil water , contamination , trichloroethylene , work (physics) , sorption , environmental chemistry , aggregate (composite) , toluene , adsorption , materials science , chemistry , thermodynamics , geology , paleontology , ecology , physics , organic chemistry , biology , composite material , metallurgy
Modeling the diffusive transport of volatile organic contaminants (VOCs) has been previously described by lumping together vastly different soil regions (e.g., interaggregate and intra‐aggregate regions) and assuming local equilibrium with linear contaminant phase distributions. This approach has sometimes failed to adequately describe diffusive transport. In this work, a diffusive transport model was developed that separately considered diffusion in the intra‐aggregate and interaggregate regions and utilized nonlinear contaminant distributions among the phases. Input parameters were determined from independent sources, calculations, and measurements. No adjustments were made to input parameters. The model was compared to breakthrough and desorption data for two VOCs (toluene and trichloroethylene) on a silt loam soil at moistures from 1.6 to 14%. Breakthrough predictions were significantly better than those from a commonly used model. Desorption predictions were excellent over the first 3 orders of magnitude in contaminant flux after which they deviated by a factor of ∼3.