| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
im
neka,*
a Dep. of Environmental Sciences, Univ. of California Riverside, CA 92521
b Institute of Environmental Science & Research, Christchurch, NZ
c George E. Brown Jr. Salinity Laboratory, USDA, ARS, Riverside, CA 92521
* Corresponding author (Jiri.Simunek{at}ucr.edu)
Received 22 December 2005.
Strongly sorbing chemicals (e.g., heavy metals, radionuclides, pharmaceuticals, and explosives) in porous media are associated predominantly with the solid phase, which is commonly assumed to be stationary. However, recent field- and laboratory-scale observations have shown that in the presence of mobile colloidal particles (e.g., microbes, humic substances, clays, and metal oxides), colloids can act as pollutant carriers and thus provide a rapid transport pathway for strongly sorbing contaminants. To address this problem, we developed a one-dimensional numerical model based on the HYDRUS-1D software package that incorporates mechanisms associated with colloid and colloid-facilitated solute transport in variably saturated porous media. The model accounts for transient variably saturated water flow, and for both colloid and solute movement due to advection, diffusion, and dispersion, as well as for solute movement facilitated by colloid transport. The colloid transport module additionally considers the processes of attachment/detachment to/from the solid phase and/or the air–water interface, straining, and/or size exclusion. Various blocking and depth dependent functions can be used to modify the attachment and straining coefficients. The solute transport module uses the concept of two-site sorption to describe nonequilibrium adsorption–desorption reactions to the solid phase. The module further assumes that contaminants can be sorbed onto surfaces of both deposited and mobile colloids, fully accounting for the dynamics of colloid movement between different phases. Application of the model is demonstrated using selected experimental data from published saturated column experiments, conducted to investigate the transport of Cd in the presence of Bacillus subtilis spores in alluvial gravel aquifer media. Numerical results simulating bacteria transport, as well as the bacteria-facilitated Cd transport, are compared with experimental results. A sensitivity analysis of the model to various parameters is also presented.
This article has been cited by other articles:
|
|
 |
|
  A. Massoudieh and T. R. Ginn Modeling Colloid-Enhanced Contaminant Transport in Stormwater Infiltration Basin Best Management Practices Vadose Zone J., November 1, 2008; 7(4): 1261 - 1268. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. A. Bradford, E. Segal, W. Zheng, Q. Wang, and S. R. Hutchins Reuse of Concentrated Animal Feeding Operation Wastewater on Agricultural Lands J. Environ. Qual., September 2, 2008; 37(5_Supplement): S-97 - S-115. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Simunek, M. Th. van Genuchten, and M. Sejna Development and Applications of the HYDRUS and STANMOD Software Packages and Related Codes Vadose Zone J., May 27, 2008; 7(2): 587 - 600. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. A. Bradford and S. Torkzaban Colloid Transport and Retention in Unsaturated Porous Media: A Review of Interface-, Collector-, and Pore-Scale Processes and Models Vadose Zone J., May 27, 2008; 7(2): 667 - 681. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Flury and H. Qiu Modeling Colloid-Facilitated Contaminant Transport in the Vadose Zone Vadose Zone J., May 27, 2008; 7(2): 682 - 697. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. Jacques, J. Simunek, D. Mallants, and M.Th. van Genuchten Modeling Coupled Hydrologic and Chemical Processes: Long-Term Uranium Transport following Phosphorus Fertilization Vadose Zone J., May 27, 2008; 7(2): 698 - 711. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
X. Qu, L. Xiao, and D. Zhu Site-Specific Adsorption of 1,3-Dinitrobenzene to Bacterial Surfaces: A Mechanism of n-{pi} Electron-Donor-Acceptor Interactions J. Environ. Qual., May 1, 2008; 37(3): 824 - 829. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. Gargiulo, S. A. Bradford, J. Simunek, P. Ustohal, H. Vereecken, and E. Klumpp Bacteria Transport and Deposition under Unsaturated Flow Conditions: The Role of Water Content and Bacteria Surface Hydrophobicity Vadose Zone J., May 1, 2008; 7(2): 406 - 419. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| The SCI Journals | Agronomy Journal | Crop Science | |||
| Journal of Natural Resources and Life Sciences Education |
Soil Science Society of America Journal | ||||
| Journal of Plant Registrations | Journal of Environmental Quality |
The Plant Genome | |||
