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United States Department of Agriculture

Agricultural Research Service

SCOTT ALAN. BRADFORD

Soil Scientist

 
 Scott A Bradford   Dr. Scott Alan Bradford
Soil Scientist

Contaminant Fate and Transport Research Unit
USDA-ARS U.S. Salinity Laboratory
450 W. Big Springs Road
Riverside, CA 92507

Phone: 951-369-4857
Fax: 951-342-4964
scott.bradford@ars.usda.gov

 

 

Research Interests:

  • Mechanisms and models for colloid and colloid-facilitated transport and fate
  • Multiphase flow, transport, and interphase mass transfer processes in porous media
  • Numerical and analytic models
  • Development and design of animal waste management practices and treatments
  • Comprehensive nutrient management plans
 

Academic Degrees:

Ph.D. Soil Science (Soil Physics), University of California, Riverside, 1995
  Dissertation: Experimental and Theoretical Investigations of Multiphase Capillarity
       
M.S. Soil Science (Soil Physics), University of California, Riverside, 1991
  Thesis: Transient State Modeling of Various Irrigation Management Strategies
       
B.S. Physics, Brigham Young University, 1989
  Minors in Chemistry and Mathematics
 

Certified:

  • Engineer-in-Training, California Board of Registration for Professional Engineers and Land Surveyors, 1992
  • Passed the 8 hour NCEES Professional Civil Engineering Exam
 

Positions:

2000-Present Soil Scientist (GS-13) USDA-ARS U.S. Salinity Laboratory
Riverside, CA
     
1999-2000 Assistant Research Scientist Dept. of Civil and Environmental Engineering,
University of Michigan, Ann Arbor, MI
     
1999-1999 Adjunct Assistant Professor Dept. of Civil and Environmental Engineering,
University of Michigan, Ann Arbor, MI
     
1997-1999 Research Investigator Dept. of Civil and Environmental Engineering,
University of Michigan, Ann Arbor, MI
     
1995-1997 Research Fellow Dept. of Civil and Environmental Engineering,
University of Michigan, Ann Arbor, MI
     
1989-1994 Research Assistant Dept. of Soil and Environmental Sciences,
University of California, Riverside, CA
     
1992-1993 Research Appointment Northwest College and University Association for Science, Pacific Northwest Laboratories,
Richland, WA
 

Professional Affiliations:

  • American Geophysical Union
  • American Society of Agronomy
  • Soil Science Society of America
 

Research Grants:

  • Kearney Foundation of Soil Science, Retention and Permeability of Multi-Fluid Soil Systems, 7/1/93-6/1/95, Total Granted $85,800, Graduate Student (Jan W. Hopmans, and Feike J. Leij Co-Principal Investigators). This proposal was based upon Dr. Bradford’s Ph.D. research proposal.
  • National Institute of Environmental Health Sciences - Superfund Basic Research Program; Investigation of the Persistence of NAPL Contamination in Natural Subsurface Systems; 4/1/95-3/31/00; Total Granted $905,556; Participating Researcher (Linda M. Abriola Project Director).
  • U.S. Department of Energy, The Migration and Entrapment of DNAPLs in Physically and Chemically Heterogeneous Porous Media, 1/1/97-12/31/99, Total Granted $582,378, Participating Researcher (Co-Principal Investigators, Drs. Linda M. Abriola and Avery H. Demond). Please note that Dr. Bradford was the principal author of this funded proposal, but his University of Michigan research title prohibited him from being listed as the co-principal investigator.
  • U.S. Department of Energy, Migration and Entrapment of DNAPLs in Heterogeneous systems: Impact of Waste and Porous Medium Composition, 10/1/00-10/1/03, Total Granted $675,000, Co-Principal Investigator (Co-Principal Investigators, Drs. Linda M. Abriola and Avery H. Demond).
  • U.S. Environmental Protection Agency, Transport and Fate of Nitrate and Pathogens at a Dairy Lagoon Water Application Site: An Assessment of CNMP Performance, 4/1/05-3/31/09, Total Approved $563,560, Principal Investigator (Co-Principal Investigators, Drs. Jirka Simunek, Martinus Th. van Genuchten, Scott Yates, Catherine Grieve, Peter Shouse, A. Mark Ibekwe, and Jim Poss).
  • U.S. Department of Agriculture, National Research Initiative, A new paradigm for pathogen transport and deposition: The role of pore structure and colloid-colloid interactions, 7/1/2006-6/30/2009, Total Granted $378,511, Principal Investigator (Co-Principal Investigators, Drs. Sharon Walker and William Johnson).
  • San Jacinto Resource Conservation District, Spatio-temporal assessment of nutrient management plan performance for field-scale lagoon water application at Scott Brothers Dairy, San Jacinto, CA, 6/1/2007-3/31/2009, Total Approved $282,869, co-Principal Investigator (Principal Investigator, Dr. Dennis Corwin; Co-Principal Investigators, Drs. Pete Shouse, and Todd Skaggs).
 

Invited Research Seminars:

  • Bradford, S. A., L. M. Abriola, and F. J. Leij. 1997. Multi-fluid hydraulic properties for fractional wettability porous media. International workshop on characterization and measurement of the hydraulic properties for unsaturated porous media, Riverside, CA. October 22-24.
  • Bradford, S. A., L. M. Abriola, and K. M. Rathfelder. 1998. Simulated entrapment and dissolution of organic liquids in chemically heterogeneous porous media. Enviromeet 98- Behavior and Remediation of Nonaqueous Phase Contaminants in the Subsurface, University of California, Irvine, CA. July 20-23.
  • Bradford, S. A. 2000. Fate and persistence of nonaqueous phase liquids in chemically heterogeneous subsurface environments. Seminar Series, University of California, Department of Civil and Environmental Engineering, Los Angeles, CA. October 10.
  • Bradford, S. A., M. Th. van Genuchten, and J. Simunek. 2001. Integrating laboratory and numerical studies in environmental engineering research. Seminar Series, University of California, Department of Chemical and Environmental Engineering, Riverside, CA. April 30.
  • Bradford, S. A., M. Th. van Genuchten, and J. Simunek. 2002. Processes and parameters to characterize pathogen transport and fate: A modeling perspective, National Program Staff (Michael Jawson), USDA-ARS Pathogen Research Group Conference Call Presentation, December 11.
  • Bradford, S. A., J. Simunek, M. Bettahar, and M. Th. van Genuchten. 2004. Straining of colloids at textural interfaces: Implications for pathogen and colloid-facilitated transport. The Third International Conference "Interfaces Against Pollution", Julich, Germany. May 24-27.
  • Bradford, S. A., J. Simunek, M. Bettahar, M. Th. van Genuchten, and S. R. Yates. 2004. Straining of colloids in porous media: Evidence, implications, and research plans. Subsurface Transport of Microorganisms, Microbiological Laboratory for Health Protection, RIVM, Bilthoven, The Netherlands. May 28.
  • Bradford, S. A., J. Simunek, M. Bettahar, M. Th. van Genuchten, and S. R. Yates. 2004. Straining of colloids: Implications for pathogen and colloid-facilitated transport. Seminar Series, University of California, Department of Environmental Sciences, Riverside, CA. September 30.
  • Bradford, S. A. 2005. An overview of pathogen transport in porous media: Processes, parameters, and mathematical modeling. Guest lecturer, Vadose Zone Processes (SWSC 217), University of California, Department of Environmental Sciences, Riverside, CA. February 22.
  • Bradford, S. A. 2005. Transport and fate of nitrate and pathogens at a dairy lagoon water application site: An assessment of CNMP performance. Western Riverside County Ag Coalition, Technical Committee, Nuevo Water Distrist, Nuevo, CA. January 12.
  • Bradford, S. A. 2007. Migration of E. coli O157:H7 from CAFOs to Produce: Potential Pathways and Treatments. 2007 Beef Industry Safety Summit, Dallas, TX. February 28.
  • Bradford, S. A., S. Torkzaban, S. L. Walker, and J. Simunek. 2007. Colloid retention in porous media at different scales: Processes and models. American Chemical Society, 81st Colloids & Surface Science Symposium, University of Delaware, Newark, DE. June 26. Keynote speaker.
  • Bradford, S. A., S. Torkzaban, F. Leij, N. Toride, J. Simunek, and M. Th. van Genuchten. 2008. Coupled effects of pore space geometry, velocity, and solution chemistry on colloid retention in porous media. American Geophysical Union Joint Assembly, Fort Lauderdale, Florida. May 27.
  • Bradford, S. A., S. Torkzaban, and J. Simunek. 2008. Colloid and colloid-facilitated transport in porous media. The Fifth International Conference "Interfaces Against Pollution", Kyoto, Japan. June 1-4. Keynote speaker.
 

Proposal Review Panels:

  • Member of the U. S. Environmental Protection Agency proposal review panel on "Complex Chemical Mixtures", Washington, D.C. September 13-14, 2000.
  • Invited to serve on the U.S. Department of Energy proposal review panel for the "Environmental Management Science Program: Research Related to Subsurface Contamination in Vadose and Saturated Zone", Office of Science, Notice 02-03. 2002 (declined offer).
  • Member of the public advisory committee for the Eastern Municipal Water District project entitled "Quantification of Nitrogen Removal under Recycled Water Recharge ponds", Perris, CA. February 2006-March 2007.
  • Member of the project advisory committee for the American Water Works Association Research Foundation project entitled "Revised Microscopic Particulate Analysis for Application of GWUDI Determination and Bank Filtration" (Project number 3121, $375,000). February 2005-Present.
 

National and International Committees:

  • Dissertation evaluation and defense committee member for Saeed Torkzaban, Utrecht University, Department of Earth Sciences, The Netherlands. July 10th, 2007.
  • Nominated to serve on the National Research Council Committee on Source Removal of Contaminants in the Subsurface. 2002.
  • USDA-ARS, National Program 206 (Manure and Byproduct Utilization) Planning Committee. April 13-15, 2004.
  • Subsurface Reactive Transport Modeling Workgroup – Organics, Federal Interagency Steering Committee on Multimedia Environmental Models. May 2004- Present.
  • International Conference "Interfaces Against Pollution", Advisory Committee, May 2004 - Present.
 

Offices and Committee Assignments Held in Professional Societies:

  • Chaired a session on "Preferential Flow of Water and Chemicals" at the Annual Meetings of the Soil Science Society of America in Anaheim, CA. 1997.
  • Associate Editor for Journal of Environmental Quality. 2003-Present.
  • Guest Editor (Dennis Corwin co-Editor) for a special issue of Journal of Environmental Quality entitled "Environmental Impact and Sustainability of Degraded Water Reuse". 2007-Present.
  • Associate Editor for Vadose Zone Journal. 2004-Present.
  • Guest Editor (Jirka Simunek co-Editor) for a special issue of Vadose Zone Journal entitled "Vadose Zone Modeling". 2007-Present.
  • Secretary, Multistate Research Project entitled "Characterizing Mass and Energy Transport at Different Scales", W1188, USDA, CSREES. 2005.
  • Chairman, Multistate Research Project entitled "Characterizing Mass and Energy Transport at Different Scales", W1188, USDA, CSREES. 2006.
  • Co-team leader (with Yakov Pachepsky), NP 206, Manure and Byproduct Utilization, Pathogens problem area 2e, Modeling fate and transport of manure-borne pathogens from "pedon" to watershed scale. April, 2004-present.
 

Course Taught at the University of Michigan:

Civil and Environmental Engineering 593 - Environmental Soil Physics (Winter 1999)
 

Journal Articles:

  1. Bradford, S. A., J. Letey, and G. E. Cardon. 1991. Simulated crop production under saline high water table conditions. Irrigation Science, 12, 73-77.
  2. Bradford, S. A., and J. Letey. 1992. Cyclic and blending strategies for using nonsaline and saline waters for irrigation. Irrigation Science, 13, 123-128.
  3. Bradford, S. A., and J. Letey. 1992. Simulated effects of water table and irrigation scheduling as factors in cotton production. Irrigation Science, 13, 101-107.
  4. Bradford, S. A., and F. J. Leij. 1995. Fractional wettability effects on two- and three-fluid capillary pressure-saturation relations. Journal of Contaminant Hydrology, 20, 89-109.
  5. Bradford, S. A., and F. J. Leij. 1995. Wettability effects on scaling two- and three-fluid capillary pressure-saturation relations. Environmental Science & Technology, 29, 1446-1455.
  6. Bradford, S. A., and F. J. Leij. 1996. Predicting two- and three-fluid capillary pressure- saturation relationships in fractional wettability media. Water Resources Research, 32, 251-260.
  7. Bradford, S. A., L. M. Abriola, and F. J. Leij. 1997. Wettability effects on two- and three- fluid relative permeabilities. Journal of Contaminant Hydrology, 28, 171-191.
  8. Bradford, S. A., and F. J. Leij. 1997. Estimating interfacial areas for multi-fluid soil systems. Journal of Contaminant Hydrology, 27, 83-105.
  9. Abriola, L. M., and S. A. Bradford. 1998. Experimental investigations of the entrapment and persistence of organic liquid contaminants in the subsurface environment. Environmental Health Perspectives, 106, 1083-1095.
  10. Bradford, S. A., L. M. Abriola, and K. M. Rathfelder. 1998. Flow and entrapment of dense nonaqueous phase liquids in physically and chemically heterogeneous aquifer formations. Advances in Water Resources, 22, 117-132.
  11. Bradford, S. A., R. A. Vendlinski, and L. M. Abriola. 1999. The entrapment and long-term dissolution of tetrachloroethylene in fractional wettability porous media. Water Resources Research, 35, 2955-2964.
  12. Bradford, S. A., T. J. Phelan, and L. M. Abriola. 2000. Dissolution of residual tetrachloroethylene in fractional wettability porous media: Correlation development and application. Journal of Contaminant Hydrology, 45, 35-61.
  13. Bradford, S. A., and L. M. Abriola. 2001. Dissolution of residual tetrachloroethylene in fractional wettability porous media: Incorporation of interfacial area estimates. Water Resources Research, 37, 1183-1195.
  14. Bradford, S. A., and J. Schijven. 2002. Release of Cryptosporidium and Giardia from dairy calf manure: Impact of solution salinity. Environmental Science & Technology, 36, 3916-3923.
  15. Bradford, S. A., S. R. Yates, M. Bettahar, and J. Simunek. 2002. Physical factors affecting the transport and fate of colloids in saturated porous media. Water Resources Research, 38(12), 1327, doi:10.1029/2002WR001340.
  16. Bradford, S. A., J. Simunek, M. Bettahar, M. Th. van Genuchten, and S. R. Yates. 2003. Modeling colloid attachment, straining, and exclusion in saturated porous media. Environmental Science & Technology, 37, 2242-2250.
  17. Bradford, S. A., K. M. Rathfelder, J. Lang, and L. M. Abriola. 2003. Entrapment and dissolution of DNAPLs in heterogeneous porous media. Journal of Contaminant Hydrology, 67, 133-157.
  18. Bradford, S. A., M. Bettahar, J. Simunek, and M. Th. Van Genuchten. 2004. Straining and attachment of colloids in physically heterogeneous porous media. Vadose Zone Journal, 3, 384-394.
  19. Schijven, J. F., S. A. Bradford, and S. Yang. 2004. Release of Cryptosporidium and Giardia from diary cattle manure: Physical factors. Journal of Environmental Quality, 33, 1499-1508.
  20. Phelan, T. J., L. D. Lemke, S. A. Bradford, D. M. O’Carroll, and L. M. Abrioila. 2004. Influence of textural and wettability variations on predictions of DNAPL persistence and plume development in saturated porous media. Advances in Water Resources, 27, 411-427.
  21. Abriola, L., M, S. A. Bradford, J. Lang, and C. L. Gaither. 2004. Volatilization of binary nonaqueous phase liquid mixtures in unsaturated porous media. Vadose Zone Journal, 3, 645-655.
  22. O'Carroll, D. M., S. A. Bradford, and L. M. Abriola. 2004. Infiltration of PCE in a system containing spatial wettability variations. Journal of Contaminant Hydrology, 73, 39-63.
  23. Bradford, S. A., and M. Bettahar. 2005. Straining, attachment, and detachment, of Cryptosporidium oocysts in saturated porous media. Journal of Environmental Quality, 34, 469-478.
  24. O’Carroll, D. M., L. M. Abriola, C. A. Polityka, S. A. Bradford, and A. H. Demond. 2005. Prediction of two-phase capillary pressure-saturation relationships in fractional wettability systems. Journal of Contaminant Hydrology, 77, 247-270.
  25. Bradford, S. A., J. Simunek, M. Bettahar, Y. F. Tadassa, M. Th. Van Genuchten, S. R. Yates. 2005. Straining of colloids at textural interfaces. Water Resources Research, 41, W10404, doi:10.1029/2004WR003675.
  26. Bradford, S. A., and M. Bettahar. 2006. Concentration dependent colloid transport in saturated porous media. Journal Contaminant Hydrology, 82, 99-117.
  27. Bradford, S. A., Y. F. Tadassa, and Y. Pachepsky. 2006. Transport of Giardia and manure suspensions in saturated porous media. Journal of Environmental Quality, 35, 749-757.
  28. Bradford, S. A., Y. F. Tadassa, and Y. Jin. 2006. Transport of coliphage in the presence and absence of manure suspension. Journal of Environmental Quality, 35, 1692-1701.
  29. Pachepsky, Y. A., A. M. Sadeghi, S. A. Bradford, D. R. Shelton, A. K. Guber, and T. Dao. 2006. Transport and fate of manure-borne pathogens: Modeling perspective. Agricultural Water Management, 86, 81-92.
  30. Simunek, J., C. He, L. Pang, and S. A. Bradford. 2006. Colloid-facilitated transport in variably-saturated porous media: Numerical model and experimental verification. Vadose Zone Journal, 5, 1035-1047.
  31. Bradford, S. A., J. Simunek, M. Bettahar, M. Th. van Genuchten, and S. R. Yates. 2006. Significance of straining in colloid deposition: Evidence and implications. Water Resources Research, 42, W12S15, doi:10.1029/2005WR004791.
  32. Bradford, S. A., J. Simunek, and S. L. Walker. 2006. Transport and straining of E. coli O157:H7 in saturated porous media. Water Resources Research, 42, W12S12, doi:10.1029/2005WR4805.
  33. Wang, Q.-Q., S. A. Bradford, W. Zheng, and S. R. Yates . 2006. Sulfadimethoxine degradation kinetics in manure as affected by initial concentration, moisture, and temperature. Journal of Environmental Quality, 35, 2162-2169.
  34. Gargiulo, G., S. A. Bradford, J. Šimunek, H. Vereecken, and E. Klumpp. 2006. Transport and deposition of metabolically active and stationary phase Deinococcus Radiodurans in unsaturated porous media. Environmental Science & Technology, 41, 1265-1271.
  35. Gargiulo, G., S. A. Bradford, J. Simunek, P. Ustohal, H. Vereecken, and E. Klumpp. 2006. Bacteria transport and deposition under unsaturated conditions: the role of the matrix grain size and the bacteria surface protein. Journal of Contaminant Hydrology, 92, 255-273.
  36. Bradford, S. A., S. Torkzaban, and S. L. Walker. 2007. Coupling of physical and chemical mechanisms of colloid straining in saturated porous media. Water Research, 41, 3012-3024.
  37. Bradford, S. A., and N. Toride. 2007. A stochastic model for colloid transport and deposition. Journal of Environmental Quality, 36, 1346-1356.
  38. Torkzaban, S., S. A. Bradford, and S. L. Walker. 2007. Resolving the coupled effects of hydrodynamics and DLVO forces on colloid attachment to porous media. Langmuir, 23, 9652-9660.
  39. Torkzaban, S., S. A. Bradford, M. Th. van Genuchten, and S. L. Walker. 2006. Colloid transport in unsaturated porous media: The role of water content and ionic strength on particle straining. Journal of Contaminant Hydrology, 96, 113-127.
  40. Zheng, W., S. R. Yates, and S. A. Bradford. 2008. Analysis of steroid hormones in dairy manure and wastewaters. Environmental Science & Technology, 42, 530-535.
  41. Gargiulo, G., S. A. Bradford, J. Simunek, P. Ustohal, H. Vereecken, and E. Klumpp. 2007. Bacteria transport and deposition under unsaturated conditions: The role of water content and bacteria surface hydrophobicity. Vadose Zone Journal, 7, 406-419.
  42. Torkzaban, S., S. S. Tazehkand, S. L. Walker, and S. A. Bradford. 2008. Transport and fate of bacteria in porous media: Coupled effects of chemical conditions and pore space geometry. Water Resources Research, 44, Art. No. W04403, doi:10.1029/2007WR006541.
  43. Bradford, S. A., and S. Torkzaban. 2008. Colloid transport and retention in unsaturated porous media: A review of interface, collector, and pore scale processes and models. Vadose Zone Journal, 7, 667-681.
  44. Bradford, S. A., E. Segal, W. Zheng, Q. Wang, and S. R. Hutchins. 2008. Reuse of CAFO waterwater on agricultural lands: Potential environmental contaminants, transport pathways, and treatments. Journal of Environmental Quality, 37, S97-S115.
  45. Segal, E., S. A. Bradford, P. Shouse, N. Lazarovitch, and D. Corwin. 2008. Integration of hard and soft data to characterize field-scale hydraulic properties for flow and transport studies. Vadose Zone Journal, 7, 878-889.
  46. Simunek, J., and S. A. Bradford. 2008. Vadose zone modeling: Introduction and importance. Vadose Zone Journal, 7:581-586.
  47. Corwin, D. L., and S. A. Bradford. 2008. Environmental Impacts and Sustainability of degraded water reuse. Journal of Environmental Quality, 37, S1-S7.
  48. Tazehkand, S. S., S. Torkzaban, S. A. Bradford, and S. L. Walker. 2008. Cell preparation methods influence E. coli D21g surface chemistry and transport in saturated porous media. Journal of Environmental Quality, 37, 2108-2115.
  49. Bradford, S. A., S. Torkzaban, F. Leij, J. Simunek, and M. Th. van Genuchten. 2009. Modeling the coupled effects of pore space geometry and velocity on colloid transport and retention. Water Resources Research, 45 (W02414).
  50. Haznedaroglu, B.Z., H.N. Kim, S.A. Bradford and S.L. Walker. 2009. Relative transport behavior of Escherichia coli O157:H7 and Salmonella enterica serovar pullorum in packed bed column systems: Influence of solution chemistry and cell concentration. Environ. Sci. Technol. 43(6):1838-1844.
  51. Kim, H.N., S.A. Bradford and S.L. Walker. 2009. Escherichia coli O157:H7 transport in saturated porous media: Role of solution chemistry and surface macromolecules Environ. Sci. Technol. 43(12):4340-4347.
  52. Segal, E., P.J. Shouse, S.A. Bradford, T.H. Skaggs and D.L. Corwin. 2009. Measuring particle size distribution using laser diffraction: Implications for predicting soil hydraulic properties. Soil Science. 174(12):639-645.
  53. Kim, H.N., S.L. Walker and S.A. Bradford. 2010. Macromolecule mediated transport and retention of Escherichia coli O157:H7 in saturated porous media. Water Research. 44:1082-1093.
  54. Torkzaban, S., H.N. Kim, J. Simunek and S.A. Bradford. 2010. Hysteresis of colloid retention and release in saturated porous media during transients in solution chemistry. Environ. Sci. Technol. 44:1662-1669.
  55. Bradford, S.A., S. Trokzaban and A. Wiegmann. 2011. Pore-scale simulations to determine the applied hydrodynamic torque and colloid immobilization. Vadose Zone J. 10:252-161.
  56. Kim, H. and S.A. Bradford. 2010. Implications of cation exchange on clay release and colloid-facilitated transport in porous media. J. Environ. Qual. 39(6):2040-2046.
  57. Corwin, D.L., S.M. Lesch, E. Segal, P.J. Shouse, T.H. Skaggs and S.A. Bradford. 2010. Comparison of model- and design-based sampling strategies for characterizing spatial variability with ECa-directed soil sampling. J. Environmental & Engineering Geophysics. 15(3):147-162.
  58. Wang, D., M. Paradelo, S.A. Bradford, W.J.G.M. Peijnenburg, L. Chu and D. Zhou. 2011. Facilitated transport of Cu with hydroxyapatite nanoparticles in saturated sand: Effects of solution ionic strength and composition. Water Research. 45:5905-5915.
  59. Bradford, S.A. and H. Kim. 2012. Causes and implications of colloid and microorganism retention hysteresis. J. Contaminant Hydrology. 138-139:83-92.
  60. Wang, D., S.A. Bradford, M. Paradelo, W. Peijnenburg. and D. Zhou. 2012. Facilitated transport of copper with hydroxyapatite nanoparticles in saturated sand. Soil Sci. Soc. Am. J. 76(2):375-388.
  61. Torkzaban, S., J. Wan, T.K. Tokunaga and S.A. Bradford. 2012. Impacts of bridging complexation on the transport of surface-modified nanoparticles in saturated sand. Journal of Contaminant Hydrology. 136-137:86-95.
  62. Zheng, W., X. Li, S.R. Yates and S.A. Bradford. 2012. Anaerobic transformation kinetics and mechanism of steriod estrogenic hormones in dairy lagoon water. Environ. Sci. and Technol. 46(10):5471-5478.
  63. Wang, D., S.A. Bradford, R.W. Harvey, B. Gao., Cang. L. and D. Zhou. 2012. Humic acid facilitates the transport of ARS-labeled hydroxyapatite nanoparticles in iron oxyhydroxide-coated acid. Environ. Sci. and Technol. 46(5):2738-2745.
  64. Bradford, S.A., S. Torkzaban, H. Kim and J. Simunek. 2012. Modeling colloid and microorganism transport and release with transients in solution ionic strength. Environmental Science and Technology (Submitted). NA.
  65. Wang, D., S.A. Bradford, R.W. Harvey, X. Hao and D. Zhou. 2012. Transport of ARS-labeled hydroxyapatite nanoparticles in saturated granular media is influenced by surface charge variability even in the presence of humic acid. Journal of Hazardous Materials. 229-230:170-176.
  66. Bradford, S.A. and S. Torkzaban. 2012. Colloid adhesive parameters for chemically heterogeneous porous media. J. Colloid Interface Science. (Submitted). NA.
  67. Kim, H., S. Walker and S.A. Bradford. 2010. Coupled factors influencing the transport and retention of cryptosporidium parvum oocxysts in saturated porous media. Water Research. 44(4):1213-1223.
  68. Bradford, S.A., V.L. Morales, W. Zhang, R.W. Harvey, A.I. Packman., Mohanram. A. and C. Welty. 2013. Transport and fate of microbial pathogens in agricultural settings. Critical Reviews in Environmental Science Technology. 43:775-893.
  69. Bradford, S.A. and S. Torkzaban. 2013. Colloid interaction energies for physically and chemically heterogeneous porous media. Langmuir. 29:3668-3676.
  70. Wang, Y., S.A. Bradford and J. Simunek. 2013. Transport and fate of microorganisms in soils with preferential flow under different solution chemistry conditions. Water Resources Research. doi:10.1002/wrcr.20174
  71. van Genuchten, M.Th., F.J. Leij, T.H. Skaggs, T. Nobuo, S.A. Bradford and E.M. Pontedeiro. 2013. Exact analytical solutions for contaminant transport in rivers 1. The equilibrium advection-dispersion equation. J. Hydrology and Hydromechanics. 61(2):146-160.
  72. van Genuchten, M.Th., F.J. Leij, T.H. Skaggs, N. Toride, S.A. Bradford and E.M. Pontedeira. 2013. Exact analytical solutions for contaminant transport in rivers 2. Transient storage and decay chain solutions. J. Hydrology and Hydromechanics. 61(3):250-259.
  73. Liang, Y., S.A. Bradford, J. Simunek, H. Vereecken and E. Klumpp. 2013. Sensitivity of the transport and retention of stabilized silver nanoparticles to physicochemical factors. Water Research. 47:2572-2582.
  74. Lee, S.R., S.R. Yates, W.P. Robarge and S.A. Bradford. 2013. Synergistic ammonia losses from animal wastewater. Atmospheric Environment. 71:245-250.
  75. Leij, F.K. and S.A. Bradford. 2013. Colloid transport in dual-permeability media. J. Contaminant Hydrology. 150:65-76.
  76. Kasel, D., S.A. Bradford, J. Simunek, T. Putz, H. Vereecken and E. Klumpp. 2013. Limited transport of functionalized multi-walled carbon nanotubes in two natural soils. Environmental Pollution. 180:152-158.
  77. Sinunek, J., D. Jacques, G. Langergraber, S.A. Bradford, M. Sejna and M.Th. van Genuchten. 2013. Numerical modeling of contaminant transport using HYDRUS and its specialized modules. J. Indian Institute of Science. 93(2):265-284.
  78. Bradford, S.A., S. Torkzaban and A. Shapiro. 2013. A theoretical analysis of colloid attachment and straining in chemically heterogenous porous media. Langmuir. 29:6944-6952.
  79. Liang, Y., S.A. Bradford, J. Simunek, M. Heggen, H. Vereecken and E. Klumpp. 2013. Retention and remobilization of stabilized silver nanoparticles in an undisturbed loamy sand soil. Environmental Science and Technology. 47(21):12229-12237.
  80. Torkzaban, S., S.A. Bradford, J. Wan, T. Tokunaga and A. Masoudih. 2013. Release of quantum dot nanoparticles in porous media: Role of cation exchange and aging time. Environmental Science and Technology. 47:11528-11536.
 

Conference Proceedings and Reports:

  1. Bradford, S. A. 1991. Transient state modeling of various irrigation management strategies. University of California, Riverside (M.S. Thesis).
  2. Leij, F. J., and S. A. Bradford. 1994. 3DADE: A computer program for evaluating three-dimensional equilibrium solute transport in porous media. U.S. Salinity Laboratory, Research Report No. 134. U.S. Salinity Laboratory, USDA, ARS, Riverside, CA.
  3. Bradford, S. A. 1995. Experimental and theoretical investigations of multiphase capillarity. University of California, Riverside (Ph.D. Dessertation).
  4. Bradford, S. A., L. M. Abriola, and K. M. Rathfelder. 1998. Simulated entrapment and dissolution of organic liquids in chemically heterogeneous porous media. In: Enviromeet 98- Behavior and Remediation of Nonaqueous Phase Contaminants in the Subsurface, University of California, Irvine, pp. 7-16.
  5. Bradford, S. A., and L. M. Abriola. 1998. Entrapment and dissolution of organic liquids in chemically heterogeneous porous media. In: IAHS Publication no. 250, Groundwater Quality: Remediation and Protection, Tubingen, Germany, pp. 167-172.
  6. Leij, F. J., M. Th. van Genuchten, S. A. Bradford, and L. M. Abriola. 1998. Analytical modeling of nonaqueous phase contamination and remediation. In: Environmeet 98 - Behavior and Remediation of Nonaqueous Phase Contaminants in the Subsurface, University of California, Irvine, pp. 161-175.
  7. Bradford, S. A., L. M. Abriola, and F. J. Leij. 1999. Multi-fluid hydraulic properties for fractional wettability porous media. In: Characterization and Measurement of the Hydraulic Properties for Unsaturated Porous Media Part 1, University of California, Riverside, pp. 165-178.
  8. Bradford, S. A., J. Simunek, M. Bettahar, M. Th. van Genuchten, and S. R. Yates. 2002. Experimental and modeling studies of colloid attachment, straining, and exclusion in saturated porous media. In: International Workshop on "Colloids and colloid-facilitated transport of contaminants in soils and sediments", Tjele, Denmark. DIAS report Plant Production no. 80, 289-296.
  9. Bradford, S. A., M. Bettahar, J. Simunek, and M. Th. van Genuchten. 2002. Transport and fate of colloids in physically heterogeneous porous media. In: International Workshop on "Colloids and colloid-facilitated transport of contaminants in soils and sediments", Tjele, Denmark. DIAS report Plant Production no. 80, 123-130.
  10. Abriola, L. M., D. M. O’Carroll, S. A. Bradford, and T. J. Phelan. 2002. Compositional effects on interfacial properties in contaminated systems: Implications for organic liquid migration and recovery. In: Computational Methods in Water Resources (Eds. Hassanizadeh, S.M., R.J. Schotting, W.G. Gray, and G.F. Pinder), XIVth International Conference on Computational Methods in Water Resources, June 23-28, 2002, Delft, The Netherlands. Elsevier, Developments in Water Science, 47, 795-802.
  11. Pachepsky, Y., S. A. Bradford, A. Sadeghi, A. Guber, and D. Shelton. 2004. Modeling fate and transport of manure-borne pathogens in the environment. In: Workshop Report Pathogens in the Environment, Kansas State University, February 2004, pp. 34-38.
  12. Simunek, J., M. Th. van Genuchten, S. A. Bradford, and R. J. Lenhard. 2005. New features in the version 3.0 of HYDRUS-1D. In: Workshop on HYDRUS: Advanced modeling of water flow and solute transport in the vadose zone, University of Utrecht, Utrecht, The Netherlands, October 17-19, pp. 86-89.
  13. Bradford, S. A., M. Th. van Genuchten, and J. Simunek. 2005. Modeling of colloid transport and deposition in porous media. In: Workshop on HYDRUS: Advanced modeling of water flow and solute transport in the vadose zone, University of Utrecht, Utrecht, The Netherlands, October 17-19, pp. 1-5.
  14. van Genuchten, M.Th., F.J. Leij, N. Toride, S.A. Bradford and T.H. Skaggs. 2006. Exact solutions for contaminant transport in rivers. In: R. M. Cotta, M. Th. van Genuchten, P. F. L. Heilbron and M. J. Ungs (eds.), Hybrid Methods in Environmental Transport Phenomena, Nova Science Publ., Inc., Hauppauge, NY (in press).
 

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