Skip to main content
ARS Home » Pacific West Area » Riverside, California » Agricultural Water Efficiency and Salinity Research Unit » People » Scott Bradford

Scott Alan Bradford

Soil Scientist


 
 Scott A Bradford   Dr. Scott Alan Bradford
Soil Scientist

Agricultural Water Efficiency and Salinity 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. Adrian, Y.F., U. Schneidewinde, S.A. Bradford, J. Simunek, T.M. Fernandez-Steeger and R. Azzam. 2017. Transport and retention of surfactant- and polymer-stabilized engineered silver nanoparticles in silicate-dominated aquifer material. Environmental Pollution. 236:195-207. doi:10.1016/j.envpol.2018.01.011.
  2. Sasidharan, S., S.A. Bradford, J. Simunek, S. Torkzaban and J. Vanderzalm. 2017. Transport and fate of viruses in sediment and stormwater from a managed aquifer recharge site. Journal of Hydrology. 555:724-735. doi:10.1016/j.jhydrol.2017.10.062.
  3. Bradford, S.A., H. Kim, C. Shen, S. Sasidharan and J. Shang. 2017. Contributions of nanoscale roughness to anomalous colloid retention and stability behavior. Langmuir. 33:10094-10105. doi:10.1021/acs.langmuir.7b02445.
  4. Shen, C., S.A. Bradford, Y. Huang, Y. Zhang and B. Li. 2017. DLVO interaction energies between hollow spherical particles and collector surfaces. Langmuir. 33:10455-10467. doi:10.1021/acs.langmuir.7b0283.
  5. Sasidharan, S., S.A. Bradford, S. Torkzaban, X. Ye, J. Vanderzalm, X. Du and D. Page. 2017. Unraveling complexities of velocity dependent retention and release parameters for E. coli in saturated porous media. Science of the Total Environment . 603:406-415. doi:10.1016/j.scitotenv.2017.06.091.
  6. Bradford, S.A., L.J. Feike, J. Schijven and S. Torkzaban. 2017. Critical role of preferential flow in field-scale pathogen transport and retention. Vadose Zone Journal. 16(4):1-13. doi:10.2136/vzj2016.12.0127.
  7. Liang, J., S.A. Bradford, J. Simunek and A. Hartmann. 2017. Adapting HYDRUS-1D to simulate overland flow and reactive transport during sheet flow deviations. Vadose Zone Journal. 16(6):1-18. doi:10.2136/vzj2016.11.0113.
  8. Zhang, M., S.A. Bradford, J. Simunek, H. Verreken and E. Klump. 2016. 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. doi:10.1016/j.watres.2016.11.0062.
  9. Zhang, M., S.A. Bradford, J. Simunek, 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?. Journal of Environmental Science and Technology. 50:12713-12721. doi:10.1021/acs.est.6b03285.
  10. Zhang, M., I. Engelhardt, J. Simunek, S.A. Bradford, D. Kasel, A.E. Berns, H. Vereecken and E. Klumpp. 2016. Co-transport of chlordecone and sulfadiazine in the presence of functionalized multi-walled carbon nanotubes in soils. Environmental Pollution. 221:470-479. doi:10.1016/j.envpol.2016.12.018.
  11. Leij, F.J., S.A. Bradford and A. Sciortino. 2016. Analytic solutions for colloid transport with time-or depth-dependent retention in porous media. Journal of Contamination Hydrology. 195:41-50. doi:10.1016/j.jconhyd.2016.10.006.
  12. Bradford, S.A. and R.W. Harvey. 2016. Future research needs involving pathogens in groundwater. Hydrogeology Journal. 1-8. doi:10.1007/s10040-016-1501-0.
  13. Sasidharan, S., S. Torkzaban, S.A. Bradford, P.G. Cook and V.V.S.R. Gupta. 2016. Temperature dependency of virus and nanoparticle transport and retention in saturated porous media. Environmental Science and Technology. 196:10-20. doi:10.1016/j.jconnhyd.2016.11.004.
  14. Sasidharan, S., S. Torkzaban, S.A. Bradford, R. Kookana, D. Page and P. Cook. 2016. Transport and retention of bacteria and viruses in biochar-amended sand. Science of the Total Environment. 548:100-109. doi:10.1016/j.scitotenv.2015.12.126.
  15. Bradford, S.A., H. Kim, B.J. Headd and S. Torkzaban. 2015. Evaluating the transport of Bacillus subtilis spores as a potential surrogate for Cryptosporidium parvum Oocysts. Environmental Science and Technology. 50:1295-1303. doi:10.1021/acs.est.5b05296.
  16. Headd, B.J. and S.A. Bradford. 2015. Use of aerobic spores as a surrogate for cryptosporidium oocysts in drinking water supplies. Water Resource. 90:185-202. doi:10.1016/j.watres.2015.12.024.
  17. Bradford, S.A. and S. Torkzaban. 2015. Determining parameters and mechanisms of colloid retention and release in porous media. Langmuir. 31:12096-12105. doi:10.1021/acs.langmuir.5b03080.
  18. Bradford, S.A., J. Schijven and T. Harter. 2015. Microbial transport and fate in the subsurface: An introduction to the special collection. Journal of Environmental Quality. 44:1333-1337. doi:10.2134/jeq2015.07.0375.
  19. Torkzaban, S. and S.A. Bradford. 2015. Critial role of surface roughness on colloid retention and release in porous media. Water Research. 88:274-284. doi:10.1016/j.watres.2015.10.022.
  20. Leij, F.J., S.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. doi:10.2134/j.req2015.03.0147.
  21. Han, Y., G. Hwang, D. Kim, S.A. Bradford, B. Lee, I. Eom, P.L. Kim, S.Q. Choi and H. Kim. 2015. Transport, retention, and long-term release behavior of ZnO nanoparticle aggregates in saturated quartz sand: Role of solution pH and biofilm coating. Water Research. 90:247. doi:10.1016/j.watres.2015.12.009.
  22. Torkzaban, S., S.A. Bradford, J.L. Vanderzalm, B. Patterson, B. Harris and H. Prommer. 2014. Colloid release and clogging in porous media: Effects of solution ionic strength and flow velocity. Journal of Contaminant Hydrology. 181:161. doi:10.1016/j.jconhyd.2015.06.005.
  23. Bradford, S.A., Y. Wang, S. Torkzaban and J. Simunek. 2015. Modeling the release of E. coli D21g with transients in water content . Water Resources Research . 51:3303-3316. doi:10.1002/2014WR016566.
  24. Bradford, S.A., B. Head, G. Ayre and J. Simunek. 2015. Transport of E. Coli D21g with runoff water under different solution chemistry conditions and surface slopes. Journal of Hydrology. 525:760-768. doi:10.1016/j.hydrol.2015.04.038.
  25. 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. 181:144-152. doi:10.1016/j.jconhyd.2015.04.003.
  26. Sun, Y., B. Gao, S.A. Bradford, L. Wu, H. Chen, X. Shi and J. Wu. 2014. Transport, retention, and size perturbation of graphene oxide in saturated porous media: Effects of input concentration and grain size. Water Research. 68:24-33. doi:10.1016/j.watres.2014.09.025.
  27. Wang, Y., S.A. Bradford and J. Simunek. 2014. Release of E.coli D21g with transients in water content. Environmental Science & Technology. 48(16):9349-9357. doi:10.1021/es501956k.
  28. Treumann, S., S. Torkzaban, S.A. Bradford, R.M. Visalakshan and D. Page. 2014. An explanation for differences in the prcess of colloid adsorption in batch and column studies. Journal of Contaminant Hydrology. 164:219-229. doi:10.1016/j.jconhyd.2014.06.007.
  29. Sasidharan, S., S. Trokzaban, S.A. Bradford, P.J. Dillon and P.G. Cook. 2014. Coupled effects of hydrodynamic and solution chemistry conditions on long-term nanoparticle transport and deposition in saturated porous media. Colloids and Surfaces A: Physicochemical and Engineering Aspects. 457:169-179. doi:10.1016/j.colsurfa.2014.05.075.
  30. Wang, Y., S.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. J. Contaminant Hydrology. 159:57-66. doi:10.1016/j.jconhyd.2014.01.009.
  31. Wang, Y., S.A. Bradford and J. Simunek. 2014. Physicochemical factors influencing the preferential transport of Escherichia coli in Soils. Vadoze Zone Journal. 1-10. doi:10.2136/vzj2013.07.0120.
  32. Bradford, S.A., Y. Wang, H. Kim, S. Torkzaban and J. Simunek. 2014. Modeling microorganism transport and survival in the subsurface. Journal of Environmental Quality. 43(2):421-440. doi:10.2134/jeq2013.05.2012.
  33. 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.
  34. 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. 12229-12237.
  35. 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.
  36. 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. 265-284.
  37. 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.
  38. Bradford, S.A. and S. Torkzaban. 2013. Colloid interaction energies for physically and chemically heterogeneous porous media. Langmuir. 29:3668-3676.
  39. Leij, F.K. and S.A. Bradford. 2013. Colloid transport in dual-permeability media. J. Contaminant Hydrology. 150:65-76.
  40. 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.
  41. 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.
  42. 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. 250-259.
  43. 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. 146-160.
  44. Kasel, D., S.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.
  45. 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. 49(5):2424-2436. doi:doi:10.1002/wrcr.20174.
  46. Bradford, S.A. and S. Torkzaban. 2012. Colloid adhesive parameters for chemically heterogeneous porous media. Langmuir. 28:13643-13651. doi:10.1021/LA3029929.
  47. 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. doi:10.1016/j.jhazmat.2012.05.089.
  48. 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. 48:1-10. doi:10.1029/2012WR012468.
  49. Wang, D., S.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 oxyhydroxide-coated acid. Environ. Sci. and Technol. 2738-2745.
  50. 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. 5471-5478.
  51. 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 Technology. 43:775-893.
  52. 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. 86-95.
  53. 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. 375-388.
  54. 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.
  55. Bradford, S.A. and H. Kim. 2012. Causes and implications of colloid and microorganism retention hysteresis. J. Contaminant Hydrology. 83-92.
  56. Bradford, S.A., S. Tokzaban 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.
  57. Kim, H. and S.A. Bradford. 2010. Implications of cation exchange on clay release and colloid-facilitated transport in porous media. J. Environ. Qual. 2040-2046.
  58. 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.
  59. 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. 15:147-162.
  60. Segal, E., P.J. Shouse, S.A. Bradford, T.H. Skaggs and D.L. Corwin. 2010. Measuring particle size distribution using laser diffraction: Implications for predicting soil hydraulic properties. Soil Science. 639-645.
  61. Torkzaban, S., S.L. Walker and S.A. Bradford. 2009. Reply to comment by William P. Johnson et al. on Transport and fate of bacteria in porous media: Coupled effects on chemical conditions and pore space geometry. Water Resources Research. 1-3.
  62. 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. 44:1213-1223.
  63. 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.
  64. 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. Environ. Sci. Technol. 6996-7002.
  65. 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.
  66. Kim, H.N., K. Hong, I. Lee, S.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.
  67. 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. 1838-1844.
  68. Bradford, S.A. and E. Segal. 2009. Fate of indicator microorganisms under nutrient management plan conditions. J. Environ. Qual. 38:1728-1738.
  69. 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. 4340-4347.
  70. Segal, E., P.J. Shouse, J.A. Poss, D.M. Crohn and S.A. Bradford. 2010. Recommendations for nutrient management plans in a semi-arid environment. Agricultural, Ecosystems and Environment. 137:317-328.
  71. Corwin, D.L. and S.A. Bradford. 2008. Environmental impacts and sustainability of degraded water reuse. J. Enviro. Qual. 37:S-1-S-7. doi:10.2134/jeq2008.0210.
  72. 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. 1-15.
  73. Segal, E., P.J. Shouse and S.A. Bradford. 2008. Deterministic analysis and upscaling of bromide transport in a heterogeneous vadose zone. Vadose Zone J. 8:601-610.
  74. Leij, F. and S.A. Bradford. 2009. Combined physical and chemical nonequilibrium transport model: Analytical solution, moments and application to colloids. J. Contaminant Hydrology. 110:87-99.
  75. Simunek, J. and S.A. Bradford. 2008. Vadose zone modeling: Introduction and importance. Vadose Zone J. 7:581-586.
  76. Tazehkand, S.S., S. Torkzaban, S.A. Bradford and S.A. Walker. 2008. Cell preparation methods influence Escherichia coli D21g surface chemistry and transport in saturated sand. J. Environ. Qual. 37:2108-2115.
  77. 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. 44:1-12.
  78. Segal, E., S.A. Bradford, P.J. Shouse, N. Lazarovitch and D.L. Corwin. 2008. Integration of hard and soft data to characterize field-scale hydraulic properties for flow and transport studies. Vadose Zone J. 7:878-889.
  79. Torkzaban, S., S.A. Bradford and S.L. Walker. 2007. Resolving the coupled effects of hydrodynamics and DLVO forces on colloid attachment in porous media. Langmuir. 23:9652-9660.
  80. Zheng, W., S.R. Yates and S.A. Bradford. 2008. Analysis of steroid hormones in a typical dairy waste disposal system. Environ. Sci. Technol. 42:530-535.
  81. Bradford, S.A., E. Segal, W. Zheng, Q. Wang and S.R. Hutchins. 2008. Reuse of concentrated animal feeding operation wastewater on agricultural lands. J. Environ. Qual. 37:S-97-S-115. doi:10.2134/jeq2007.0393.
  82. 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 J. 7:667-681.
  83. Bradford, S.A. and N. Toride. 2007. A stochastic model for colloid transport and deposition. J. Environ. Qual. 36:1346-1356.
  84. 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 prespective. Ag. Water Management. 86:81-92.
  85. 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.
  86. Torkzaban, S., 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.
  87. Gargiulo, G., S.A. Bradford, J. Simunek, H. Vereecken and E. Klumpp. 2007. Transport and deposition of metabolically active and stationary phase Deinococcus Radiodurans in unsaturated porous media. Environ. Sci. Technol. 41:1265-1271.
  88. Gargiulo, G., S.A. Bradford, J. Simunek, H. Vereecken and E. Klumpp. 2007. Bacteria transport under unsaturated conditions: The role of the matrix grain size and the bacteria surface protein. J. Contaminant Hydrology. 92:255-273.
  89. Gargiulo, G., S.A. Bradford, J. Simunek, P. Ustohal, H. Vereecken and E. Klumpp. 2008. Bacteria transport and deposition under unsaturated conditions: The role of water content and bacteria surface hydrophobicity. Vadose Zone J. 406-419.
  90. Wang, Q., S.A. Bradford, W. Zheng and S.R. Yates. 2006. Sulfadimethoxine degradation kinetics in manure as affected by initial concentration, moisture, and temperature. J. Environ. Qual. 35:2162-2169.
  91. Simunek, J., C. He, L. Pang and S.A. Bradford. 2006. Colloid-facilitated solute transport in variably-saturated porous media: Numerical model and experimental verification. Vadose Zone J. 5:1035-1047.
  92. Bradford, S.A., J. Simunek and S.L. Walker. 2006. Transport and deposition of E. Coli OH157:H7 in saturated porous media. Water Resources Research. 1-12.
  93. 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. 1-16.
  94. Bradford, S.A., Y.F. Tadassa and Y.A. Pachepsky. 2006. Transport of Giardia and manure suspensions in saturated porous media. J. Environ. Qual. 35:749-757.
  95. Bradford, S.A., Y.F. Tadassa and Y. Jin. 2006. Transport of coliphage in the presence and absence of manure suspension. Environ. Sci. Technol. 35:1692-1701.
  96. 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. J. Contsminant Hydrology. 77:247-270.
  97. Bradford, S.A., J. Simunek, M. Bettahar, Y.F. Tadassa, M.Th. van Genuchten and S.R. Yates. 2004. Straining of colloids at textural interfaces. Water Resour. Res. 41(10):W10404. doi:10.1029/2004WR003675.
  98. 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 J. 3:384-394.
  99. 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 J. 3:645-655.
  100. Phelan, T.J., L.D. Lemke, S.A. Bradford, D.M. O'Carroll and L.M. Abriola. 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.
  101. Bradford, S.A. and M. Bettahar. 2004. Straining and attachment of Cryptosporidium oocysts in saturated porous media. Environvironmental Science & Technoly. 34(2):469-478. doi:10.2134/jeq2005.0469.
  102. Bradford, S.A. and M. Bettahar. 2006. Concentration dependent transport of colloids in saturated porous media. J. Contaminant Hydrology. 82:99-117.
  103. 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. Environ. Sci. Technol. 37:2242-2250.
  104. O'Carroll, D.M., S.A. Bradford and L.M. Abriola. 2004. Infiltration of PCE in a system containing spatial wettability variations. J. Contaminant Hydrology. 73:39-63.
  105. Schijven, J.F., S.A. Bradford and S. Yang. 2004. Release of Cryptosporidium and Giardia from dairy cattle manure: Physical factors. J. Environ. Qual. 33:1499-1508.
  106. Bradford, S.A. and J.F. Schijven. 2002. Release of Cryptosporidium and giardia from dairy calf manure: Impact of solution salinity. Journal of Environmental Sciences & Technology. 36:3916-3923.
  107. Bradford, S.A., K.M. Rathfelder, J. Lang and L.M. Abriola. 2003. Entrapment and dissolution of DNAPLs in heterogeneous porous media. J. Contaminant Hydrology. 67:133-157.
  108. 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):63-1-63-12. doi:10.1029/2002WR001340.
  109. Bradford, S.A. and F.J. Leij. 1995. Estimating interfacial areas for multi-fluid soil systems. Journal of Contaminant Hydrology. 27:83-105.
  110. Bradford, S.A. and F.J. Leij. 1995. Predicting two-and three-fluid capillary pressure-saturation relationships in mixed wettability media. Water Resources Research. 32:251-259.
  111. Bradford, S.A. and F.J. Leij. 1994. Fractional wettability effects on two- and three-fluid capillary pressure-saturation relations. Journal of Contaminant Hydrology. 20:89-109.
  112. Bradford, S.A. and F.J. Leij. 1994. Wettability effects on scaling two- and three-fluid capillary pressure saturation relations. Environmental Science & Technology. 29:1446-1455.
  113. Bradford, S. A., and J. Letey. 1992. Cyclic and blending strategies for using nonsaline and saline waters for irrigation. Irrigation Science, 13, 123-128.
  114. 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.
  115. Bradford, S. A., J. Letey, and G. E. Cardon. 1991. Simulated crop production under saline high water table conditions. Irrigation Science, 12, 73-77.
 

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.