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Applied Geology and Geochemistry

Wooyong Um

Wooyong Um

Pacific Northwest National Laboratory
PO Box 999
Richland, WA 99352


Dr. Um joined Pacific Northwest National Laboratory (PNNL) in 2002 and has worked for radionuclides sorption and desorption at the Hanford Site, reactivity and mineral dissolution/secondary precipitation by leaked caustic tank wastes solution, XMT studies for pore structure changes, geochemical studies for the performance assessment of proposed low-level radioactive wastes repository at the Hanford Site, synthesis of novel nanoporous getter materials to enhance anionic radionuclide sequestration, and low-temperature waste form development and 99Tc immobilization. Dr. Um is also an Adjunct professor in the department of Environmental Sciences and Regional Planning at Washington State University (Tri-city) from June 1, 2004 to present as well as a visiting professor in the department of advanced nuclear engineering at Pohang University of Science and Technology (POSTECH) in South Korea from October 1, 2010 to present.

Research Interests

  • Metal and radioactive wastes isolation and immobilization techniques development
  • Performance assessment of low-level radioactive waste repository
  • Contaminated soils characterization and remediation method development
  • In situ X-ray Absorption Spectroscopy (XAS) for sorption at the soil/water interface
  • Sorption and desorption studies of heavy metals and radionuclides
  • Rate and mass transfer studies of solute uptake by earth materials.
  • Geochemical surface complexation modeling of ion sorption/desorption
  • X-ray Photoelectron Spectroscopy (XPS) for studies of surface complexes
  • Pore structure and diffusion measurements using X-ray Micro-Tomography (XMT)
  • Metal complex and speciation affecting on bioavailability and toxicity
  • Fate and transport of metal and radionuclides (As, Se, I, Cr, U, and Tc)
  • Modified zeolites or synthesis of novel nanoporous sorbents
  • Reactive transport modeling of radionuclides and metals coupled with biogeochemical reactions.
  • Reclamation and remediation of acid mine drainage (AMD)
  • Deep geological CO2 sequestration and geochemical reaction model
  • Biological remediation of contaminated soils and groundwater
  • Physicochemical characterization techniques of mineral surfaces including particle size distribution, surface area, carbon contents, pore size distribution, scanning electron microscopy, x-ray diffraction, and potentiometric titrations.

Education and Credentials

  • Ph.D., Hydrogeology, University of Nevada, Reno, 2001
  • M.S., Geology (Geophysics), Yonsei University, Seoul, South Korea, 1994
  • B.S., Geology, Yonsei University, Seoul, South Korea, 1990

Affiliations and Professional Service

  • American Geophysical Union
  • American Water Resources Association
  • National Ground Water Association
  • American Chemical Society

Awards and Recognitions

  • Recipient of 2010 PNNL Outstanding Performance Award
  • Recipient of the 2009 DOE Outstanding Mentor Award
  • Listed in the 2009/2011/2012 Edition of Who's Who in America (Marquis)
  • Recipient of George B. and Jane C. Maxey Award, Desert Research Institute, 2001
  • Recipient of Geological Society of America research grants, 2000
  • Honor as an outstanding student in University of Nevada, Reno, 1998
  • Recipient of Nevada Medal fellowship, 1998
  • Recipient of Korea government scholarship, 1995 – 1998

PNNL Publications


  • Smith FN, W Um, CD Taylor, DS Kim, MJ Schweiger, and AA Kruger. 2016. "Computational Investigation of Technetium(IV) Incorporation into Inverse Spinels: Magnetite (Fe3O4) and Trevorite (NiFe2O4)." Environmental Science & Technology 50(10):5216-5224.  doi:10.1021/acs.est.6b00200
  • Cantrell KJ, JH Westsik, Jr, RJ Serne, W Um, and AD Cozzi. 2016. Secondary Waste Cementitious Waste Form Data Package for the Integrated Disposal Facility Performance AssessmentPNNL-25194, Pacific Northwest National Laboratory, Richland, WA. 
  • Carroll SA, WJ Carey, D Dzombak, NJ Huerta, L Li, T Richard, W Um, SD Walsh, and LIWEI ZHANG. 2016. "Review: Role of Chemistry, Mechanics, and Transport on Well Integrity in CO2 Storage Environments." International Journal of Greenhouse Gas Control 49:149-160.  doi:10.1016/j.ijggc.2016.01.010
  • Kabilan S, HB Jung, AP Kuprat, ANR Beck, T Varga, CA Fernandez, and W Um. 2016. "Numerical Simulation of Permeability Change in Wellbore Cement Fractures after Geomechanical Stress and Geochemical Reactions Using X-ray Computed Tomography Imaging." Environmental Science & Technology 50(12):6180-6188.  doi:10.1021/acs.est.6b00159
  • Lee MS, W Um, G Wang, AA Kruger, WW Lukens, RJ Rousseau, and VA Glezakou. 2016. "Impeding 99Tc(IV) mobility in novel waste forms." Nature Communications 7:Article No. 12067.  doi:10.1038/ncomms12067
  • Um W, MMV Snyder, and G Wang. 2016. Liquid Secondary Waste Grout Formulation and Waste Form QualificationPNNL-25129;RPT-SWCS-005, REV0, Pacific Northwest National Laboratory, Richland, WA. 


  • Jung HB, J Yang, and W Um. 2015. "Bench-scale electrokinetic remediation for cesium-contaminated sediment at the Hanford Site, USA." Journal of Radioanalytical and Nuclear Chemistry 304(2):615-625.  doi:10.1007/s10967-014-3852-0
  • Smith FN, CD Taylor, W Um, and AA Kruger. 2015. "Technetium incorporation into goethite (a-FeOOH): An atomic-scale investigation." Environmental Science & Technology 49(22):13699-13707.  doi:10.1021/acs.est.5b03354
  • Um W, J Yang, RJ Serne, and JH Westsik, Jr. 2015. "Reductive Capacity Measurement of Waste Forms for Secondary Radioactive Wastes." Journal of Nuclear Materials 467(Part 1):251-259.  doi:10.1016/j.jnucmat.2015.09.045
  • Khan M, and W Um. 2015. "Liquid scintillation counting methodology for 99Tc analysis: A remedy for radiopharmaceutical waste." Analytical Chemistry 87(17):9054-9060.  doi:10.1021/acs.analchem.5b02279
  • Shao H, S Kabilan, SA Stephens, N Suresh, ANR Beck, T Varga, PF Martin, AP Kuprat, HB Jung, W Um, A Bonneville, DJ Heldebrant, KC Carroll, J Moore, and CA Fernandez. 2015. "Environmentally Friendly, Rheoreversible, Hydraulic-fracturing Fluids for Enhanced Geothermal Systems." Geothermics 58:22-31.  doi:10.1016/j.geothermics.2015.07.010
  • Um W, SA Luksic, G Wang, DS Kim, MJ Schweiger, PR Hrma, and AA Kruger. 2015. "Development of Tc(IV)-Incorporated Fe Minerals to Enhance 99Tc Retention in Glass Waste Form ." In Annual Waste Mangement Symposium (WM2015), March 15 - 19, 2015, Phoenix, Arizona, vol. 7, pp. 5451-5457.  Waste Mangement Symposia, Inc., TUCSON, AZ. 


  • Snyder MMV, and W Um. 2014. "ADSORPTION MECHANISMS AND TRANSPORT BEHAVIOR BETWEEN SELENATE AND SELENITE ON DIFFERENT SORBENTS." International Journal of Waste Resources 4(2):Article No. 1000144. 
  • Snyder MMV, and W Um. 2014. "ADSORPTION MECHANISMS AND TRANSPORT BEHAVIOR BETWEEN SELENATE AND SELENITE ON DIFFERENT SORBENTS." International Journal of Waste Resources 4(2):Article No. 144. 
  • Bonneville A, HB Jung, H Shao, S Kabilan, W Um, KC Carroll, T Varga, N Suresh, SA Stephens, and CA Fernandez. 2014. "Stimuli Responsive/Rheoreversible Hydraulic Fracturing Fluids for Enhanced Geothermal Energy Production (Part II)." In American Geophysical Union, Fall Meeting, December 15-19, 2014, San Francisco, California, pp. Abstract #H43A-0934.  American Geophysical Union, Washington, DC. 
  • Cantrell KJ, W Um, BD Williams, ME Bowden, BN Gartman, WW Lukens, EC Buck, and EJ Mausolf. 2014. "Chemical Stabilization of Hanford Tank Residual Waste." Journal of Nuclear Materials 446(1-3):246-256.  doi:10.1016/j.jnucmat.2013.10.060
  • Choi J, W Um, and S Choung. 2014. "Development of iron phosphate ceramic waste form to immobilize radioactive waste solution." Journal of Nuclear Materials 452(1-3):16-23.  doi:10.1016/j.jnucmat.2014.04.033
  • Choung S, W Um, S Choi, AJ Francis, S Kim, J Park, and SH Kim. 2014. "Biogeochemical Changes at Early Stage After the Closure of Radioactive Waste Geological Repository in South Korea." Annals of Nuclear Energy 71:6-10.  doi:10.1016/j.anucene.2014.03.021
  • Choung S, MK Kim, J Yang, MG Kim, and W Um. 2014. "Effects of Radiation and Temperature on Iodide Sorption by Surfactant-Modified Bentonite." Environmental Science & Technology 48(16):9684-9691.  doi:10.1021/es501661z
  • Chung CW, J Chun, G Wang, and W Um. 2014. "Effects of Iron Oxides on the Rheological Properties of Cementitious Slurry." Colloids and Surfaces. A, Physicochemical and Engineering Aspects 453:94-100.  doi:10.1016/j.colsurfa.2014.03.072
  • Jung HB, S Kabilan, JP Carson, AP Kuprat, W Um, PF Martin, ME Dahl, TA Kafentzis, T Varga, SA Stephens, BW Arey, KC Carroll, A Bonneville, and CA Fernandez. 2014. "Wellbore cement fracture evolution at the cement-basalt caprock interface during geologic carbon sequestration." Applied Geochemistry 47:1-16.  doi:10.1016/j.apgeochem.2014.04.010
  • Kanematsu M, N Perdrial, W Um, J Chorover, and PA O'Day. 2014. "Influence of phosphate and silica on U(VI) precipitation from acidic and neutralized wastewaters." Environmental Science & Technology 48(11):6097-6106.  doi:10.1021/es4056559
  • Um W, HB Jung, S Kabilan, CA Fernandez, and CF Brown. 2014. "Geochemical and geomechanical effects on wellbore cement fractures." Energy Procedia 63:5808-5812.  doi:10.1016/j.egypro.2014.11.613
  • Um W, HB Jung, S Kabilan, DM Suh, and CA Fernandez. 2014. Geochemical and Geomechanical Effects on Wellbore Cement Fractures: Data Information for Wellbore Reduced Order Model PNNL-23148, Pacific Northwest National Laboratory, Richland, WA. 


  • Jung HB, and W Um. 2013. "Experimental study of potential wellbore cement carbonation by various phases of carbon dioxide during geologic carbon sequestration." Applied Geochemistry 35:161-172.  doi:10.1016/j.apgeochem.2013.04.007
  • Jung HB, W Um, and KJ Cantrell. 2013. "Effect of Oxygen Co-Injected with Carbon Dioxide on Gothic Shale Caprock-CO2-Brine Interaction during Geologic Carbon Sequestration." Chemical Geology 354:1-14.  doi:10.1016/j.chemgeo.2013.06.019
  • Wang G, and W Um. 2013. "Facilitated Strontium Transport by Remobilization of Strontium-Containing Secondary Precipitates in Hanford Site Subsurface." Journal of Hazardous Materials 248-249:364-370.  doi:10.1016/j.jhazmat.2013.01.021
  • Beckingham LE, CA Peters, W Um, KW Jones, and WB Lindquist. 2013. "2D and 3D imaging resolution trade-offs in quantifying pore throats for prediction of permeability." Advances in Water Resources 62(Part A):1-12.  doi:10.1016/j.advwatres.2013.08.010
  • Choung S, W Um, MK Kim, and MG Kim. 2013. "Uptake Mechanism for Iodine Species to Black Carbon." Environmental Science & Technology 47(18):10349-10355.  doi:10.1021/es401570a
  • Chung CW, J Chun, W Um, SK Sundaram, and JH Westsik, Jr. 2013. "Setting and Stiffening of Cementitious Components in Cast Stone Waste Form for Disposal of Secondary Wastes from the Hanford waste treatment and immobilization plant." Cement and Concrete Research 46:14-22.  doi:10.1016/j.cemconres.2013.01.003
  • Jung HB, DP Jansik, and W Um. 2013. "Imaging Wellbore Cement Degradation by Carbon Dioxide under Geologic Sequestration Conditions Using X-ray Computed Microtomography." Environmental Science & Technology 47(1):283-289.  doi:10.1021/es3012707
  • Riley BJ, J Chun, W Um, WC Lepry, J Matyas, MJ Olszta, X Li, K Polychronopoulou, and MG Kanatzidis. 2013. "Chalcogen-Based Aerogels as Sorbents for Radionuclide Remediation." Environmental Science & Technology 47(13):7540-7547.  doi:10.1021/es400595z
  • Um W, G Wang, and RJ Serne. 2013. "The Effects of Secondary Mineral Precipitates on 90Sr Mobility at the Hanford Site, USA." Procedia Earth and Planetary Science 7:855-858.  doi:10.1016/j.proeps.2013.03.032
  • Um W, G Wang, HB Jung, and RA Peterson. 2013. Technetium Removal Using Tc-Goethite CoprecipitationPNNL-22967; EMSP-RPT-017, Pacific Northwest National Laboratory, Richland, WA. 
  • Um W, HB Jung, G Wang, JH Westsik, Jr, and RA Peterson. 2013. Characterization of Technetium Speciation in Cast StonePNNL-22977; EMSP-RPT-015, Pacific Northwest National Laboratory, Richland, WA. 
  • Xu K, PR Hrma, W Um, and J Heo. 2013. "Iron phosphate glass for immobilization of 99Tc." Journal of Nuclear Materials 441(1-3):262-266.  doi:10.1016/j.jnucmat.2013.06.008


  • Wang G, and W Um. 2012. "Mineral Dissolution and Secondary Precipitation on Quartz Sand in Simulated Hanford Tank Solutions Affecting Subsurface Porosity." Journal of Hydrology 472-473:159-168.  doi:10.1016/j.jhydrol.2012.09.021
  • Chung CW, W Um, MM Valenta, SK Sundaram, J Chun, KE Parker, ML Kimura, and JH Westsik, Jr. 2012. "Characteristics of Cast Stone Cementitious Waste Form for Immobilization of Secondary Wastes from Vitrification Process." Journal of Nuclear Materials 420(1-3):164-174.  doi:10.1016/j.jnucmat.2011.09.021
  • Crandell LE, CA Peters, W Um, KW Jones, and WB Lindquist. 2012. "Changes in the pore network structure of Hanford sediment after reaction with caustic tank wastes." Journal of Contaminant Hydrology 131(1-4):89-99.  doi:10.1016/j.jconhyd.2012.02.002
  • Um W, HS Chang, JP Icenhower, WW Lukens, RJ Serne, N Qafoku, RK Kukkadapu, and JH Westsik, Jr. 2012. "Iron Oxide Waste Form for Stabilizing 99Tc." Journal of Nuclear Materials 429(1-3):201-209.  doi:10.1016/j.jnucmat.2012.06.004
  • Um W, and HB Jung. 2012. Results of Laboratory Scale Fracture Tests on Rock/Cement InterfacesPNNL-21446, Pacific Northwest National Laboratory, Richland, WA. 
  • Wang G, RJ Serne, MJ Lindberg, W Um, BN Bjornstad, BD Williams, IV Kutynakov, Z Wang, and N Qafoku. 2012. Uranium in Hanford Site 300 Area: Extraction Data on Borehole SedimentsPNNL-22032, Pacific Northwest National Laboratory, Richland, WA. 


  • Chang HS, W Um, KA Rod, RJ Serne, A Thompson, N Perdrial, CI Steefel, and J Chorover. 2011. "Strontium and cesium release mechanisms during unsaturated flow through waste-weathered Hanford sediments ." Environmental Science & Technology 45(19):8313-9320.  doi:10.1021/es2010368
  • Qafoku N, PE Dresel, JP McKinley, ES Ilton, W Um, CT Resch, RK Kukkadapu, and SW Petersen. 2011. Geochemical Characterization of Chromate Contamination in the 100 Area Vadose Zone at the Hanford Site - Part 2PNNL-17865, Pacific Northwest National Laboratory, Richland, WA. 
  • Cantrell KJ, H Shao, CJ Thompson, L Zhong, HB Jung, and W Um. 2011. FY12 ARRA-NRAP Report - Studies to Support Risk Assessment of Geologic Carbon SequestrationPNNL-21802, Pacific Northwest National Laboratory, Richland, WA. 
  • Hess NJ, M Oostrom, MA Celia, M Hilpert, Q Kang, LJ Pyrak-Nolte, TD Scheibe, AM Tartakovsky, CJ Werth, D Wildenschild, C Zhang, SE Bialkowski, TA Ghezzehei, G Tang, F Doster, J Kumar, R Parashar, R Gerlach, H Yoon, GD Redden, T Zhang, H Huang, J Nogues, W Deng, H Resat, KA Rod, DR Baer, RT Kelly, W Um, G Wang, MC Richmond, DR Rector, ML Stewart, HB Jung, and C Plata. 2011. EMSL Pore Scale Modeling Challenge/WorkshopPNNL-21086, Pacific Northwest National Laboratory, Richland, WA. 
  • Kim BC, J Lee, W Um, J Kim, J Joo, JH Lee, JH Kwak, JH Kim, C Lee, H Lee, RS Addleman, T Hyeon, MB Gu, and J Kim. 2011. "Magnetic mesoporous materials for removal of environmental wastes." Journal of Hazardous Materials 192(3):1140-1147.  doi:10.1016/j.jhazmat.2011.06.022
  • Sundaram SK, KE Parker, MM Valenta, SG Pitman, J Chun, CW Chung, ML Kimura, CA Burns, W Um, and JH Westsik, Jr. 2011. Secondary Waste Form Development and Optimization-Cast StonePNNL-20159 Rev. 1, Pacific Northwest National Laboratory, Richland, WA. 
  • Um W, HB Jung, PF Martin, and BP McGrail. 2011. Effective Permeability Change in Wellbore Cement with Carbon Dioxide ReactionPNNL-20843, Pacific Northwest National Laboratory, Richland, WA. 
  • Um W, HS Chang, JP Icenhower, WW Lukens, RJ Serne, N Qafoku, JH Westsik, Jr, EC Buck, and SC Steven. 2011. "Immobilization of 99-Technetium (VII) by Fe(II)-Goethite and Limited Reoxidation." Environmental Science & Technology 45(11):4904-4913.  doi:10.1021/es104343p
  • Um W, MM Valenta, CW Chung, J Yang, MH Engelhard, RJ Serne, KE Parker, G Wang, KJ Cantrell, and JH Westsik, Jr. 2011. Radionuclide Retention Mechanisms in Secondary Waste-Form Testing: Phase II PNNL-20753, Pacific Northwest National Laboratory, Richland, WA. 


  • Rod KA, W Um, and M Flury. 2010. "Transport of Strontium and Cesium in Simulated Hanford Tank Waste Leachate through Quartz Sand under Saturated and Unsaturated Flow ." Environmental Science & Technology 44(21):8089-8094.  doi:10.1021/es903223x
  • Pierce EM, KJ Cantrell, JH Westsik, Jr, KE Parker, W Um, MM Valenta, and RJ Serne. 2010. Secondary Waste Form Screening Test Results-Cast Stone and Alkali Alumino-Silicate Geopolymer PNNL-19505, Pacific Northwest National Laboratory, Richland, WA. 
  • Pierce EM, SV Mattigod, JH Westsik, Jr, RJ Serne, JP Icenhower, RD Scheele, W Um, and N Qafoku. 2010. Review of Potential Candidate Stabilization Technologies for Liquid and Solid Secondary Waste StreamsPNNL-19122, Pacific Northwest National Laboratory, Richland, WA. 
  • Um W, H Chang, JP Icenhower, N Qafoku, SC Smith, RJ Serne, EC Buck, RK Kukkadapu, ME Bowden, JH Westsik, Jr, and WW Lukens. 2010. Immobilization and Limited Reoxidation of Technetium-99 by Fe(II)-GoethitePNNL-19833, Pacific Northwest National Laboratory, Richland, WA. 
  • Um W, JM Zachara, C Liu, DA Moore, and KA Rod. 2010. "Resupply Mechanism to a Contaminated Aquifer: A Laboratory Study of U(VI) Desorption from Capillary Fringe Sediments." Geochimica et Cosmochimica Acta 74(18):5155-5170. 
  • Um W, JP Icenhower, CF Brown, RJ Serne, Z Wang, CJ Dodge, and AROKIASAMYJ FRANCIS. 2010. "Characterization of Uranium-Contaminated Sediments From Beneath A Nuclear Waste Storage Tank From Hanford, Washington: Implications for Contaminant Transport and Fate." Geochimica et Cosmochimica Acta 74(4):1363-1380. 


  • Um W, RJ Serne, GV Last, and ET Glossbrenner. 2009. "The effect of gravel size fraction on the distribution coefficients of selected radionuclides radionuclides ." Journal of Contaminant Hydrology 107(1-2):82-90. 
  • Um W, RJ Serne, GV Last, RE Clayton, and ET Glossbrenner. 2009. "The effect of gravel size fraction on the distribution coefficients of selected radionuclides." Journal of Contaminant Hydrology 107(1-2):82-90.  doi:10.1016/j.jconhyd.2009.04.003
  • Cai R, WB Lindquist, W Um, and KW Jones. 2009. "Tomographic Analysis of Reactive Flow Induced Pore Structure Changes in Column Experiments ." Advances in Water Resources 9(32):1396-1403.  doi:10.1016/j.advwatres.2009.06.006
  • Serne RJ, AL Ward, W Um, BN Bjornstad, DF Rucker, DC Lanigan, and MW Benecke. 2009. Electrical Resistivity Correlation to Vadose Zone Sediment and Pore-Water Composition for the BC Cribs and Trenches AreaPNNL-17821, Pacific Northwest National Laboratory, Richland, WA. 
  • Um W, MJ Truex, MM Valenta, C Iovin, IV Kutnyakov, H Chang, RE Clayton, RJ Serne, AL Ward, CF Brown, KN Geiszler, ET Clayton, SR Baum, and DM Smith. 2009. Characterization of Sediments from the Soil Desiccation Pilot Test (SDPT) Site in the BC Cribs and Trenches AreaPNNL-18800, Pacific Northwest National Laboratory, Richland, WA. 
  • Um W, Z Wang, RJ Serne, BD Williams, CF Brown, CJ Dodge, and AROKIASAMYJ FRANCIS. 2009. "Uranium Phases in Contaminated Sediments Below Hanford's U Tank Farm ." Environmental Science & Technology 43(12):4280-4286.  doi:10.1021/es900203r



  • Um W, RJ Serne, and KM Krupka. 2007. "Surface complexation modeling of U(VI) sorption to Hanford sediment with varying geochemical conditions." Environmental Science & Technology 41(10):3587-3592. 
  • Um W, SV Mattigod, RJ Serne, GE Fryxell, DH Kim, and LD Troyer. 2007. "Synthesis of nanoporous zirconium oxophosphate and application for removal of U(VI)." Water Research 41(15):3217-3226. 
  • Brown CF, JP Icenhower, W Um, BN Bjornstad, MM Valenta, C Iovin, DC Lanigan, RE Clayton, KN Geiszler, ET Clayton, IV Kutnyakov, SR Baum, MJ Lindberg, and RD Orr. 2007. Characterization of Direct-Push Vadose Zone Sediments from the 241-B and 241-BX Tank Farms PNNL-17162, Pacific Northwest National Laboratory, Richland, WA. 
  • Shin Y, GE Fryxell, W Um, KE Parker, SV Mattigod, and R Skaggs. 2007. "Sulfur-Functionalized Mesoporous Carbon." Advanced Functional Materials 17(15):2897-2901.  doi:10.1002/adfm.200601230
  • Um W, RJ Serne, CF Brown, and GV Last. 2007. "U(VI) Adsorption on Aquifer Sediments at the Hanford Site." Journal of Contaminant Hydrology 93(1-4):255-269. 
  • Williams BA, CF Brown, W Um, MJ Nimmons, RE Peterson, BN Bjornstad, DC Lanigan, RJ Serne, FA Spane, and ML Rockhold. 2007. Limited Field Investigation Report for Uranium Contamination in the 300 Area, 300-FF-5 Operable Unit, Hanford Site, WashingtonPNNL-16435, Pacific Northwest National Laboratory, Richland, WA. 
  • Zachara JM, CF Brown, JN Christensen, JA Davis, PE Dresel, C Liu, SD Kelly, JP McKinley, RJ Serne, and W Um. 2007. A Site Wide Perspective on Uranium Geochemistry at the Hanford SitePNNL-17031, Pacific Northwest National Laboratory, Richland, WA. 



  • Um W, and RJ Serne. 2005. "Sorption and transport behavior of radionuclides in the proposed low-level radioactive waste repository at the Hanford site, Washington." Radiochimica Acta 93(1):57-63.  doi:10.1524/ract.
  • Um W, RJ Serne, SB Yabusaki, and AT Owen. 2005. "Enhanced radionuclide immobilization and flow path modifications by dissolution and secondary precipitates ." Journal of Environmental Quality 34(4):1404-1414.  doi:10.2134/jeq2004.0395
  • Um W, RJ Serne, BN Bjornstad, HT Schaef, CF Brown, VL Legore, KN Geiszler, SR Baum, MM Valenta, IV Kutnyakov, TS Vickerman, and MJ Lindberg. 2005. Characterization of 200-UP-1 Aquifer Sediments and Results of Sorption-Desorption Tests Using Spiked Uncontaminated GroundwaterPNNL-15502, Pacific Northwest National Laboratory, Richland, WA. 


  • Um W, and C Papelis. 2004. "Metal ion sorption and desorption on zeolitized tuffs from the Nevada Test Site." Environmental Science and Technology 38(2):496-502. 
  • Um W, RJ Serne, and KM Krupka. 2004. "Linearity and Reversibility of Iodide Adsorption on Sediments from Hanford, Washington Under Water Saturated Conditions." Water Research 38(8):2009-2016. 
  • Diallo MS, S Christie, P Swaminathan, Balogh, XIANGYANG Shi, W Um, C Papelis, WA Goddard, and JH Johnson. 2004. "Dendritic chelating agents. 1. Cu(II) binding to ethylene diamine core poly (amidoamine) denderimers in aqueous solutions." Langmuir 20(7):2640-2651. 
  • Um W, RJ Serne, SB Yabusaki, VL Freedman, SD Samson, and KL Nagy. 2004. "The role of secondary mineral precipitates on radionuclide sequestration at the Hanford Site." In Proceedings of the eleventh international symposium Water-Rock Interaction, WRI-11, vol. 1, ed. RB Wanty and RR Seal, pp. 715-718.  AA Balkema, Leiden, NY. 


  • Um W, and C Papelis. 2003. "Sorption mechanisms of Sr and Pb on zeolitized tuffs from the Nevada test site as a function of pH and ionic strength." American Mineralogist 88(11-12 Pt.2):2028-2039. 
  • Papelis C, W Um, CE Russel, and JB Chapman. 2003. "Measuring the specific surface area of natural and manmade glasses: effects of formation process, morphology, and particle size." Colloids and Surfaces. A, Physicochemical and Engineering Aspects 215(1-3):221-239. 


  • Um W, and C Papelis. 2002. "Geochemical effects on colloid-facilitated metal transport through zeolitized tuffs from the Nevada Test Site." Environmental Geology 43(1-2):209-218. 


Additional Information