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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:

  • Passed the 8 hour NCEES Professional Civil Engineering Exam

 

Present and Past Positions:

2000-Present Soil Scientist (GS-15) USDA-ARS U.S. Salinity Laboratory
Riverside, CA
     
1999 Adjunct Assistant Professor Dept. of Civil and Environmental Engineering,
University of Michigan, Ann Arbor, MI
     
1995-2000 Postdoctoral Positions (Assistant Research Scientist, Research Investigator, and Research Fellow) Dept. of Civil and Environmental Engineering,
University of Michigan, Ann Arbor, MI

 

Professional Research and Publications:

Dr. Bradford is a world renowned expert in the field of mechanisms and models to describe colloid (nanoparticles, microorganisms, and clays) and colloid-facilitated transport and fate in the environment.  He has authored over 124 publications on a wide variety of topics in soil physics, contaminant hydrology, and environmental engineering.  Most of these publications appeared in peer-reviewed journals.  He has a Google Scholar H-factor of 45 (45 publications with more than 45 citations), and is first-author on 3 invited review papers.

 

Awards:

  • Excellence in Review Award, Environmental Science & Technology, 2012.
  • Fellow of the Soil Science Society of America.
  • Fellow of the American Society of Agronomy.
 

Research Grants:

  • Co-Principal investigator on proposals totaling more than $2.6 million.
 

Special Invitations:

  • Over 37 invited presentations to national and international audience, including 5 keynote addresses.
 

Professional Affiliations:

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

Professional Service:

  • Editor in Chief for Critical Reviews of Environmental Science and Technology (2017-present), Technical Editor for Journal of Environmental Quality (JEQ, 2014-2016), Associate Editor (AE) for JEQ (2003-2006), and AE for Vadose Zone Journal (VZJ, 2004-2013).
  • Co-organizer of special issues in JEQ (2008 and 2015) and VZJ (2008), and sessions at annual meetings of SSSA (1997 and 2006) and AGU (2008, 2010, and 2011).
  • Co-organizer of conference entitled “Aerobic Spores and Other Microbial Indicators for Determining Groundwater Under the Direct Influence of Surface Water”.  This conference was held in Riverside, CA on Sept. 6-8, 2016.
  • International Conference “Interfaces Against Pollution”, Advisory Committee, May 2004 - 2012.
  • Secretary (2005) and chair (2006) of the W1188 Multistate Research Project entitled “Characterizing Mass and Energy Transport at Different Scales”, USDA, CSREES.
  • USDA-ARS, National Program 206 (Manure and Byproduct Utilization) Planning Committee. April 13-15, 2004.
  • 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, 2004-2009.
  • ASA and SSSA Fellows Committee 2014 and 2015.
  • University faculty promotion and tenure evaluation committees (3).
  • Dissertation evaluation and defense committees of 6 PhD students, and also informally supervised and mentored research activities of 7 other PhD students.
  • Reviewer for numerous technical journals (>21), funding organizations (7), proposal evaluation committees (2), and project advisor committees (3).
 

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 of porous media with 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 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., A. Bradford, and S. Yang.  2004.  Release of Cryptosporidium and Giardia from dairy cattle manure: Physical factors.  Journal of Environmental Quality, 33, 1499-1508.
  20. Phelan, T. J., L. D. Lemke, 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, 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., 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, 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., 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, 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 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., 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., 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., 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., 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., A. Bradford, J. Simunek, P. Ustohal, H. Vereecken, and E. Klumpp.  2007.  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., 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., 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., A. Bradford, M. Th. van Genuchten, and S. L. Walker.  2008.  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 A. Bradford.  2008.  Analysis of steroid hormones in dairy manure and wastewaters.  Environmental Science & Technology, 42, 530-535.
  41. Gargiulo, G., A. Bradford, J. Simunek, P. Ustohal, H. Vereecken, and E. Klumpp.  2008.  Bacteria transport and deposition under unsaturated flow 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 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 concentrated animal feeding operation waterwater on agricultural lands.  Journal of Environmental Quality, 37, S97-S115.
  45. Segal, E., 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 A. Bradford.  2008.  Vadose zone modeling: Introduction and importance.  Vadose Zone Journal, 7:581-586.
  47. Corwin, D. L., and A. Bradford.  2008.  Environmental Impacts and Sustainability of degraded water reuse.  Journal of Environmental Quality, 37, S1-S7. 
  48. Tazehkand, S. S., S. Torkzaban, 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, doi:10.1029/2008WR007096.
  50. Haznedaroglu, B. Z., H. N. Kim, 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.  Environmental Science & Technology, 43, 1838-1844.
  51. Segal, E., P. Shouse, and A. Bradford.  2009.  Deterministic analysis and upscaling of bromide transport in a heterogeneous vadose zone.  Vadose Zone Journal, 8:601-610.
  52. Bradford, S. A., and E. Segal.  2009 Fate of indicator microorganisms under nutrient management plan conditions.  Journal of Environmental Quality, 38:1728-1738.
  53. Kim, H. N., A. Bradford, and S. L. Walker.  2009.  Escherichia coli O157:H7 transport in saturated porous media: Role of solution chemistry and surface macromolecules.  Environmental Science & Technology, 43 (12), 4340-4347
  54. Kim, H. N., Y. Hong, I. Lee, A. Bradford, and S. L. Walker.  2009.  Surface characteristics and adhesion behavior of Escherichia coli O157:H7: Role of extracellular macromolecules.  Biomacromolecules, 10, 2556-2564.  
  55. Bradford, S. A., H. N. Kim, B. Z. Haznedaroglu, S. Torkzaban, and S. L. Walker.  2009.  Coupled factors influencing concentration dependent colloid transport and retention in saturated porous media, Environmental Science & Technology, 43, 6996-7002.
  56. Torkzaban, S., S. L. Walker, and A. Bradford.  2009.  Reply to comment by William P. Johnson et al. on “Transport and fate of bacteria in porous media:  Coupled effects of chemical conditions and pore space geometry”, Water Resources Research, 45, W09604, doi:10.1029/2008WR007576.
  57. Segal, E., P. J. Shouse, 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 Journal, 174, 639-645.
  58. Leij, F. J., and A. Bradford.  2009.  Combined physical and chemical nonequilibrium transport model: Analytical solution, moments, and application to colloids.  Journal of Contaminant Hydrology, 110, 87-99.
  59. Kim, H. N., S. L. Walker, and A. Bradford.  2010.  Macromolecule mediated transport and retention of Escherichia coli O157:H7 in saturated porous media.  Water Research, 44, 1082-1093.
  60. Kim, H. N., S. L. Walker, and A. Bradford.  2010.  Coupled factors influencing the transport and retention of Cryptosporidium Parvum oocysts in saturated porous media.  Water Research, 44, 1213-1223.
  61. Torkzaban, S., H. N. Kim, J. Simunek, and A. Bradford.  2010.  Hysteresis of colloid retention and release in saturated porous media during transients in solution chemistry.  Environmental Science & Technology, 44, 1662-1669.
  62. Segal, E., P. Shouse, J. A. Poss, D. M. Crohn, and A. Bradford.  2010.  Recommendations for nutrient management plans in a semi-arid environment. Agriculture, Ecosystems & Environment, 137, 317-328.
  63. Bradford, S. A., and H. Kim.  2010.  Implications of cation exchange on clay release and colloid-facilitated transport in porous media.  Journal of Environmental Quality, 39, 2040-2046.
  64. Corwin, D. L., S. M. Lesch, E. Segal, P. J. Shouse, T. H. Skaggs, and A. Bradford.  2010.  Comparison of model- and design-based sampling strategies for characterizing spatial variability with ECa-directed directed soil sampling.  Journal of Environmental and Engineering Geophysics, 15, 147-162.
  65. Bradford, S. A., S. Torkzaban, and A. Wiegmann.  2011.  Pore-scale simulations to determine the applied hydrodynamic torque and colloid immobilization.  Vadose Zone Journal, 10, 252-261. 
  66. Bradford, S. A., S. Torkzaban, and J. Simunek.  2011.  Modeling colloid transport and retention in saturated porous media under unfavorable attachment conditions.  Water Resources Research, 47, W10503, doi:10.1029/2011WR010812.
  67. Wang, D., M. Paradelo, 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.
  68. Wang, D., A. Bradford, M. Paradelo, W. J. G. M. Peijnenburg, and D. Zhou.  2012.  Facilitated Transport of Cu with hydroxyapatite nanoparticles in saturated sand:  Effects of velocity, pH, and iron oxide grain coating.  Soil Science Society of America Journal, 76, 375-388.
  69. Wang, D., A. Bradford, R. W. Harvey, B. Gao, L. Cang, and D. Zhou.  2012.  Humic acid facilitates the transport of ARS-labeled hydroxyapatite nanoparticles in iron oxide-coated sand.  Environmental Science & Technology, 46, 2735-2745.
  70. Zheng, W., X. Li, S. R. Yates, and A. Bradford.  2012.  Anaerobic transformation kinetics of steroid estrogenic hormones in dairy lagoon water.  Environmental Science & Technology, 46, 5471-5478.
  71. Torkzaban, S., J. Wan, T. Tokunaga, and 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.
  72. Wang, D., 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. 
  73. Bradford, S. A., and H. Kim.  2012.  Causes and implications of colloid and microorganism retention hysteresis.  Journal of Contaminant Hydrology, 138-139, 83-92.
  74. Bradford, S. A., S. Torkzaban, H. Kim, and J. Simunek.  2012.  Modeling colloid and microorganism transport and release with transients in solution ionic strength.  Water Resources Research, 48, W09509, doi:10.1029/2012WR012468. 
  75. Bradford, S. A., and S. Torkzaban.  2012.  Colloid adhesive parameters for chemically heterogeneous porous media.  Langmuir, 28, 13643-13651.
  76. Kasel, D., A. Bradford, J. Simunek, M. Heggen, H. Vereecken, and E. Klumpp. 2013.  Transport and retention of multi-walled carbon nanotubes in saturated porous media:  Effects of input concentration and grain size.  Water Research, 47, 933-944.
  77. Bradford, S. A., V. L. Morales, W. Zhang, R. W. Harvey, A. I. Packman, A. Mohanram, and C. Welty. 2013.  Transport and Fate of Microbial Pathogens in Agricultural Settings.  Critical Reviews in Environmental Science and Technology, 43, 775-893.
  78. Lee, S., S. R. Yates, W. P. Robarge, and S. A. Bradford.  2013.  Synergistic ammonia losses from animal wastewater.  Atmospheric Environment, 71, 245-250.
  79. Liang, Y., 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.
  80. Bradford, S., and S. Torkzaban.  2013.  Colloid interaction energies for physically and chemically heterogeneous porous media.  Langmuir, 29, 3668-3676.
  81. van Genuchten, M. Th., F. J. Leij, T. H. Skaggs, N. Toride, A. Bradford, and E. M. Pontedeiro.  2013.  Exact analytical solutions for contaminant transport in rivers, 1.  The equilibrium advection-dispersion equation.  Journal of Hydrology and Hydromechanics, 61, 146-160.
  82. van Genuchten, M. Th., F. J. Leij, T. H. Skaggs, N. Toride, A. Bradford, and E. M. Pontedeiro.  2013.  Exact analytical solutions for contaminant transport in rivers, 2.  Transient storage and decay chain solutions.  Journal of Hydrology and Hydromechanics, 61, 250-259.
  83. Wang, Y., A. Bradford, and J. Simunek.  2013.  Transport and fate of microorganisms in soils with preferential flow under different solution chemistry conditions.  Water Resources Research, 49, 2424-2436.
  84. Leij, F. J., and A. Bradford. 2013.  Colloid transport in dual-permeability media.  Journal of Contaminant Hydrology, 150, 65-76.
  85. Kasel, D., A. Bradford, J. Simunek, T. Putz, H. Vereecken, and E. Klumpp. 2013.  Limited transport of functionalized multi-walled carbon nanotubes in two natural soils.  Environ. Poll., 180, 152-158.
  86. Bradford, S., S. Torkzaban, and A. Shapiro.  2013.  A theoretical analysis of colloid attachment and straining in chemically heterogeneous porous media.  Langmuir, 29, 6944-2952.
  87. Simunek, J., D. Jacques, G. Langergraber, A. Bradford, M. Šejna, and M. Th. van Genuchten. 2013. Numerical modeling of contaminant transport using HYDRUS and its specialized modules. Journal of the Indian Institute of Science, 93(2), 265-284.
  88. Torkzaban, S., A. Bradford, J. Wan, T. Tukunaga, and A. Masoudih.  2013.  Release of quantum dot nanoparticles in porous media:  Role of cation exchange and aging time.  Environmental Science & Technology, 47:11528-11536.
  89. Liang, Y., 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 & Technology, 47, 12229-12237.
  90. Wang, Y., A. Bradford, and J. Simunek.  2014.  Physical and chemical factors influencing the transport and fate of E. coli D21g in soils with preferential flow.  Vadose Zone Journal, 13, no. 1, doi:10.2136/vzj2013.07.0120.
  91. Bradford, S., Y. Wang, H. Kim, S. Torkzaban, and J. Simunek.  2014.  Modeling microorganism transport and survival in the subsurface.  Journal of Environmental Quality, 43:421-440.   
  92. Wang, Y., A. Bradford, and J. Simunek.  2014. Estimation and upscaling of dual-permeability model parameters for the transport of E.coli D21g in soils with preferential flow.  Journal of Contaminant Hydrology, 159:57-66. 
  93. Sasidharan, S., S. Torkzaban, A. Bradford, P. J. Dillon, and P. G. Cook.  2014. Coupled effects of hydrodynamic and solution chemistry on long-term nanoparticle transport and deposition in saturated porous media.  Colloids and Surfaces A:  Physicochemical and Engineering Aspects, 457:169-179.
  94. Treumann, S., S. Torkzaban, A. Bradford, R. M. Visalakshan, and D. Page.  2014.  An explanation for differences in the amount of colloid retention in batch and column studies.  Journal of Contaminant Hydrology, 164:219-229.
  95. Wang, Y., A. Bradford, and J. Simunek.  2014. Release of E. coli D21g with transients in water content.  Environmental Science & Technology, 48:9349-9357. 
  96. Sun, Y., B. Gao, A. Bradford, L. Wu, H. Chen, X. Shi, and J. Wu. 2015. Transport, retention, and size perturbation of graphene oxide in saturated porous media: Effects of input concentration and grain size.  Water Research, 68:24-33.
  97. Bradford, S. A., Y. Wang, S. Torkzaban, and J. Simunek.  2015.  Modeling the release of coli D21g with transients in water content.  Water Resources Research, 51, 3303-3316.
  98. Bradford, S. A., S. Torkzaban, F. Leij, and J. Simunek.  2015.  Equilibrium and kinetic models for colloid release under transient solution chemistry conditions.  Journal of Contaminant Hydrology, 181, 141-152.
  99. Bradford, S. A., G. Ayre, and J. Simunek.  2015.  Transport of coli D21g with runoff water under different solution chemistry conditions and surface slopes.  Journal of Hydrology, 525, 760-768.
  100. Leij, F. J., A. Bradford, Y. Wang, and A. Sciortino. 2015. Langmuirian blocking of irreversible colloid retention: Analytical solution, moments, and setback distance.  Journal of Environmental Quality, 44, 1473-1482.
  101. Torkzaban, S., A. Bradford, J. L. Vanderzalm, B. Patterson, B. Harris, and H. Prommer.  Colloid release and clogging in porous media: Effects of solution ionic strength and flow velocity. Journal of Contaminant Hydrology, 181, 161-171.
  102. Bradford, S. A., J. Schijven, and T. Harter.  2015.  Microbial transport and fate in the subsurface environment: An introduction to the special collection.  Journal of Environmental Quality, 44, 1333-1337.
  103. Torkzaban, S., and A. Bradford.  2016.  Critical role of surface roughness on colloid retention and release in porous media.  Water Research, 88, 274-284.
  104. Bradford, S. A., and S. Torkzaban.  2015.  Determining parameters and mechanisms of colloid retention and release in porous media.  Langmuir.  31, 12096–12105.
  105. Han, Y., G. Hwang, D. Kim, A. Bradford, B. Lee, I. Eom, P. J. Kim, S. Q. Choi, and H. Kim.  2016.  Transport, retention, and long-term release behavior of ZnO nanoparticle aggregates in saturated quartz sand coated: Role of solution pH and biofilm coating.  Water Research, 90, 247-257.
  106. Headd, B., and A. Bradford.  2016.  Use of aerobic spores as a surrogate for Cryptosporidium oocysts in surface water and groundwater.  Water Research, 90, 185-202.
  107. Sasidharan, S., S. Torkzaban, A. Bradford, R. Kookana, D. Page, and P. G. Cook.  2016.  Transport of bacteria and viruses in biochar-amended sand. Science of the Total Environment, 548-549, 100-109.
  108. Bradford, S. A., H. Kim, B. Headd, and S. Torkzaban.  2016.  Evaluating the transport of Bacillus subtilis spores as a potential surrogate for Cryptosporidium parvum oocysts.  Environmental Science & Technology, 50, 1295-1303.
  109. Bradford, S., and R. Harvey. 2017. Future research needs involving pathogens in groundwater.  Hydrogeology Journal, In Press.
  110. Zhang, M., A. Bradford, J. Šimůnek, H. Vereecken, and E. Klumpp. 2016. Do goethite surfaces really control the transport and retention of multi-walled carbon nanotubes in chemically heterogeneous porous media?Environmental Science & Technology, 50, 12713-12721.
  111. Leij, F.J., A. Bradford, and A. Sciortino. 2016. Analytic solutions for colloid transport with time-and depth-dependent retention in porous media.Journal of Contaminant Hydrology, 195, 40–51.
  112. Zhang, M., A. Bradford, J. Šimůnek, H. Vereecken, and E. Klumpp.  2017.  Roles of cation valance and exchange on the retention and colloid-facilitated transport of functionalized multi-walled carbon nanotubes in a natural soil.  Water Research, 109, 358-366.
  113. Sasidharan, S., S. Torkzaban, A. Bradford, P. G. Cook, and V. V. Gupta.  2017. Temperature dependency of virus and nanoparticle transport and retention in saturated porous media.J. Contamin. Hydrol., 196:10-20.
  114. Zhang, M., I. Engelhardt, J. Šimůnek, A. Bradford, D. Kasel, A. E. Berns, H. Vereecken, and E. Klumpp.  2017.  Co-transport of chlordecone and sulfadiazine in the presence of functionalized multi-walled carbon nanotubes in soils. Environ. Poll., 221:470-479.
 

Conference Proceedings and Reports:

  1. Bradford, S. A. Transient state modeling of various irrigation management strategies.  University of California, Riverside (M.S. Thesis).
  2. Leij, F. J., and 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. 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, 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.

 

  1. 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.
  2. 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.
  3. Abriola, L. M., D. M. O’Carroll, 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.
  4. Pachepsky, Y., 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.
  5. Simunek, J., M. Th. van Genuchten, 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.
  6. 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.
  7. Bradford, S.A. Transport and fate of nutrients and indicator microorganisms at a dairy lagoon water application site:  An assessment of nutrient management plans.  EPA 600/R-10/116.
  8. Simunek, J., A. Bradford, D. Jacques, G. Langergraber, M. Sejna, D. Mallants, and M. Th. Van Genuchten.  2012.  Using the HYDRUS models to account for processes at the macro- and pore-scale (with emphasis on colloid transport and transport of reactive solutes).  Interpore Research Spotlight, November, 2012.
 

Last Modified: 2/17/2017
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