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Fundamental and Computational Sciences Directorate

Staff information


John Zachara

Physical Sciences
Battelle Fellow
Pacific Northwest National Laboratory
PO Box 999
MSIN: K8-96
Richland, WA 99352


Dr. John Zachara has performed extensive experimental research on various geochemical and biogeochemical processes that control the concentrations, fate, and transport of organic, metal and radionuclide contaminants in subsurface environments. The research has ranged from fundamental surface chemical and spectroscopic studies of mineral suspensions in the laboratory, to comprehensive studies of solute mobilization and transport in the field. He has been active in evaluating complex co-contaminant interactions that occur in contaminant mixtures and in applying multi-component adsorption models to contaminant binding in mineralogically complex natural materials. He has made important contributions to understanding how microorganisms interact with mineral surfaces through his long-term collaboration with microbiologist Dr. Jim Fredrickson.

Dr. Zachara's current research is focused on the geochemical behavior of metals and radionuclides with emphasis on the Hanford site, the influence of subsurface microbial processes on mineral surface chemistry and mineralization, and reactive transport chemistry. His research is assisted by applications of electron microscopy, scanning probe microscopy, Mössbauer spectroscopy, laser-induced fluorescence spectroscopy, and x-ray absorption spectroscopy. Dr. Zachara has been committed to identifying and performing fundamental research that provides basis for remedial action and closure decisions at the Hanford site.

Dr. Zachara received the prestigious E.O. Lawrence Award for Environmental Science and Technology in 2007 from the U.S. Department of Energy. He is a former coordinator of the DOE/OBER co-contaminant chemistry research subprogram, former associate director of the William R. Wiley Environmental Molecular Sciences Laboratory at PNNL, current chief scientist for Hanford's Science and Technology program, and co-coordinator of the PNNL/EMSL Biogeochemistry Grand Challenge along with Dr. Jim Fredrickson.

Dr. Zachara has over 125 peer-reviewed publications in leading environmental/geochemical journals on contaminant environmental geochemistry.

Research Interests

  • Biogeochemical processes influencing the fate and transport of metals & radionuclides in subsurface environments.
  • Biogeochemical electron transfer mechanisms at the microbial cell-mineral interface and resulting impacts on mineral surface chemistry.
  • Linking phenomena at the molecular and microscopic scales to contaminant behavior in the field.
  • Mineral transformations, including chemical and microbiological weathering and mineralization reactions, and their impact on contaminant reactive transport.
  • Mineral surface chemistry including adsorption, surface precipitation, and heterogeneous electron transfer, and their linkage with other environmental processes.
  • Solving DOE’s complex legacy waste management problems through the application of targeted, fundamental science.

Education and Credentials

  • Ph.D., Soil Chemistry, Washington State University
  • M.S., Soil/Watershed Chemistry, University of Washington
  • B.S., Chemistry, Bucknell University

Affiliations and Professional Service

  • American Geophysical Union
  • American Chemical Society
  • American Association for the Advancement of Science
  • Soil Science Society of America
  • Clay Minerals Society
  • Geochemical Society of America

Awards and Recognitions

  • Battelle Fellow, 2010
  • E.O. Lawrence Award, 2007
  • Fellow, American Association for the Advancement of Science
  • Fellow, Pacific Northwest National Laboratory
  • One of ISI’s (Institute of Scientific Information) most cited environmental scientists

PNNL Publications


  • Stegen JC, TC Johnson, JK Fredrickson, MJ Wilkins, AE Konopka, WC Nelson, EV Arntzen, WB Chrisler, RK Chu, SJ Fansler, EB Graham, DW Kennedy, CT Resch, MM Tfaily, and JM Zachara. 2018. "Influences of organic carbon speciation on hyporheic corridor biogeochemistry and microbial ecology." Nature Communications 9:Article No. 585.  doi:10.1038/s41467-018-02922-9


  • Zhou T, M Huang, J Bao, Z Hou, EV Arntzen, RD Mackley, AR Crump, AE Goldman, X Song, Y Xu, and JM Zachara. 2017. "A New Approach to Quantify Shallow Water Hydrologic Exchanges in a Large Regulated River Reach." Water 9(9):703.  doi:10.3390/w9090703
  • Bisht G, M Huang, T Zhou, X Chen, H Dai, G Hammond, W Riley, JL Downs, Y Liu, and JM Zachara. 2017. "Coupling a Three-Dimensional Subsurface Flow and Transport Model with a Land Surface Model to Simulate Stream-Aquifer-Land Interactions (CP v1.0)." Geoscientific Model Development 10(12):4539-4562.  doi:10.5194/gmd-10-4539-2017
  • Dai H, X Chen, M Ye, X Song, and JM Zachara. 2017. "A Geostatistics-Informed Hierarchical Sensitivity Analysis Method for Complex Groundwater Flow and Transport Modeling." Water Resources Research 53(5):4327-4343.  doi:10.1002/2016WR019756
  • Hou Z, WC Nelson, JC Stegen, CJ Murray, EV Arntzen, AR Crump, DW Kennedy, MC Perkins, TD Scheibe, JK Fredrickson, and JM Zachara. 2017. "Geochemical and Microbial Community Attributes in Relation to Hyporheic Zone Geological Facies." Scientific Reports 7:Article No. 12006.  doi:10.1038/s41598-017-12275-w
  • Li M, Y Gao, W Qian, L Shi, Y Liu, WC Nelson, CD Nicora, CT Resch, CJ Thompson, S Yan, JK Fredrickson, JM Zachara, and C Liu. 2017. "Targeted quantification of functional enzyme dynamics in environmental samples for microbially mediated biogeochemical processes." Environmental Microbiology Reports 9(5):512-521.  doi:10.1111/1758-2229.12558
  • Liu Y, C Liu, WC Nelson, L Shi, F Xu, Y Liu, A Yan, L Zhong, CJ Thompson, JK Fredrickson, and JM Zachara. 2017. "Effect of Water Chemistry and Hydrodynamics on Nitrogen Transformation and Microbial Community Functional Potential in Hyporheic Zone Sediment Columns." Environmental Science & Technology 51(9):4877-4886.  doi:10.1021/acs.est.6b05018
  • Song HS, DG Thomas, JC Stegen, M Li, C Liu, X Song, X Chen, JK Fredrickson, JM Zachara, and TD Scheibe. 2017. "Regulation-structured dynamic metabolic model provides a potential mechanism for delayed enzyme response in denitrification process." Frontiers in Microbiology 8:1866.  doi:10.3389/fmicb.2017.01866


  • Zachara JM, X Chen, CJ Murray, and G Hammond. 2016. "River Stage Influences on Uranium Transport in a Hydrologically Dynamic Groundwater-Surface Water Transition Zone." Water Resources Research 52(3):1568-1590.  doi:10.1002/2015WR018009
  • Zachara JM, JJ Moran, CT Resch, SR Lindemann, AR Felmy, ME Bowden, AB Cory, and JK Fredrickson. 2016. "Geo- and Biogeochemical Processes in a Heliothermal Hypersaline Lake." Geochimica et Cosmochimica Acta 181:144-163.  doi:10.1016/j.gca.2016.02.001
  • Zachara JM, SL Brantley, JD Chorover, RP Ewing, SN Kerisit, C Liu, E Perfect, G Rother, and AG Stack. 2016. "Internal Domains of Natural Porous Media Revealed: Critical Locations for Transport, Storage, and Chemical Reaction." Environmental Science & Technology 50(6):2811-2829.  doi:10.1021/acs.est.5b05015


  • Liu Y, JK Fredrickson, JM Zachara, and L Shi. 2015. "Direct Involvement of ombB, omaB and omcB Genes in Extracellular Reduction of Fe(III) by Geobacter sulfurreducens PCA." Frontiers in Microbiology 6:Article No. 1075.  doi:10.3389/fmicb.2015.01075
  • Johnson TC, R Versteeg, JN Thomle, GE Hammond, X Chen, and JM Zachara. 2015. "Four-dimensional electrical conductivity monitoring of stage-driven river water intrusion: Accounting for water table effects using a transient mesh boundary and conditional inversion constraints." Water Resources Research 51(8):6177-6196.  doi:10.1002/2014WR016129
  • Liu C, Y Liu, SN Kerisit, and JM Zachara. 2015. "Pore-Scale Process Coupling and Effective Surface Reaction Rates in Heterogeneous Subsurface Materials." Reviews in Mineralogy and Geochemistry 80(1):191-216.  doi:10.2138/rmg.2015.80.06
  • Liu Y, C Liu, C Zhang, X Yang, and JM Zachara. 2015. "Pore and Continuum Scale Study of the Effect of Subgrid Transport Heterogeneity on Redox Reaction Rates ." Geochimica et Cosmochimica Acta 163:140-155.  doi:10.1016/j.gca.2015.04.039
  • Liu Y, C Liu, RK Kukkadapu, JP McKinley, JM Zachara, AE Plymale, MD Miller, T Varga, and CT Resch. 2015. "99Tc(VII) Retardation, Reduction, and Redox Rate Scaling in Naturally Reduced Sediments." Environmental Science & Technology 49(22):13403-13412.  doi:10.1021/acs.est.5b03273
  • Scheibe TD, WA Perkins, MC Richmond, MI McKinley, PDJ Romero Gomez, M Oostrom, TW Wietsma, JA Serkowski, and JM Zachara. 2015. "Pore-Scale and Multiscale Numerical Simulation of Flow and Transport in a Laboratory-Scale Column." Water Resources Research 51(2):1023-1035.  doi:10.1002/2014WR015959
  • Wang Z, Z Shi, L Shi, GF White, DJ Richardson, TA Clarke, JK Fredrickson, and JM Zachara. 2015. "Effects of soluble flavin on heterogeneous electron transfer between surface-exposed bacterial cytochromes and iron oxides." Geochimica et Cosmochimica Acta 163:299-310.  doi:10.1016/j.gca.2015.03.039
  • Yan S, Y Liu, C Liu, L Shi, J Shang, H Shan, JM Zachara, JK Fredrickson, DW Kennedy, CT Resch, CJ Thompson, and SJ Fansler. 2015. "Nitrate bioreduction in redox-variable low permeability sediments." Science of the Total Environment 539:185-195.  doi:10.1016/j.scitotenv.2015.08.122


  • Lee JH, JM Zachara, JK Fredrickson, SM Heald, JP McKinley, AE Plymale, CT Resch, and DA Moore. 2014. "Fe(II)- and Sulfide-Facilitated Reduction of 99Tc(VII)O4- in Microbially Reduced Hyporheic Zone Sediments." Geochimica et Cosmochimica Acta 136:247-264.  doi:10.1016/j.gca.2013.08.017
  • Shang J, C Liu, Z Wang, and JM Zachara. 2014. "Long-term Kinetics of Uranyl Desorption from Sediments Under Advective Conditions." Water Resources Research 50(2):855-870.  doi:10.1002/2013WR013949
  • Shi L, JK Fredrickson, and JM Zachara. 2014. "Genomic Analyses of Bacterial Porin-Cytochrome Gene Clusters." Frontiers in Microbiology 5:Article No. 657.  doi:10.3389/fmicb.2014.00657
  • Edwards M, N Baiden, A Johs, SJ Tomanicek, L Liang, L Shi, JK Fredrickson, JM Zachara, AJ Gates, JN Butt, D Richardson, and TA Clarke. 2014. "The X-ray crystal structure of Shewanella oneidensis OmcA reveals new insight at the microbe-mineral interface." FEBS Letters 588(10):1886-1890.  doi:10.1016/j.febslet.2014.04.013
  • Liu C, J Shang, H Shan, and JM Zachara. 2014. "Effect of Subgrid Heterogeneity on Scaling Geochemical and Biogeochemical Reactions: A Case of U(VI) Desorption." Environmental Science & Technology 48(3):1745-1752.  doi:10.1021/es404224j
  • Liu Y, Z Wang, J Liu, C Levar, M Edwards, JT Babauta, DW Kennedy, Z Shi, H Beyenal, DR Bond, TA Clarke, JN Butt, DJ Richardson, KM Rosso, JM Zachara, JK Fredrickson, and L Shi. 2014. "A trans-outer membrane porin-cytochrome protein complex for extracellular electron transfer by Geobacter sulfurreducens PCA." Environmental Microbiology Reports 6(6):776-785.  doi:10.1111/1758-2229.12204
  • Ma R, C Liu, J Greskowiak, H Prommer, JM Zachara, and C Zheng. 2014. "Influence of calcite on uranium(VI) reactive transport in the groundwater-river mixing zone." Journal of Contaminant Hydrology 156:27-37.  doi:10.1016/j.jconhyd.2013.10.002
  • Ma R, C Zheng, C Liu, J Greskowiak, H Prommer, and JM Zachara. 2014. "Assessment of Controlling Processes for Field-Scale Uranium Reactive Transport under Highly Transient Flow Conditions." Water Resources Research 50(2):1006-1024.  doi:10.1002/2013WR013835
  • Wang Z, JM Zachara, J Shang, C Jeon, J Liu, and C Liu. 2014. "Investigation of U(VI) Adsorption in Quartz-Chlorite Mineral Mixtures." Environmental Science & Technology 48(14):7766-7773.  doi:10.1021/es500537g


  • Chen X, GE Hammond, CJ Murray, ML Rockhold, VR Vermeul, and JM Zachara. 2013. "Applications of Ensemble-based Data Assimilation Techniques for Aquifer Characterization using Tracer Data at Hanford 300 Area." Water Resources Research 49:1-13.  doi:10.1002/2012WR013285
  • Shi Z, JM Zachara, Z Wang, L Shi, and JK Fredrickson. 2013. "Reductive Dissolution of Goethite and Hematite by Reduced Flavins." Geochimica et Cosmochimica Acta 121:139-154.  doi:10.1016/j.gca.2013.05.039
  • Liu C, J Shang, SN Kerisit, JM Zachara, and W Zhu. 2013. "Scale-Dependent Rates of Uranyl Surface Complexation Reaction in Sediments." Geochimica et Cosmochimica Acta 105:326-341.  doi:10.1016/j.gca.2012.12.003
  • Stoliker DL, C Liu, DB Kent, and JM Zachara. 2013. "Characterizing particle-scale equilibrium adsorption and kinetics of uranium(VI) desorption from U-contaminated sediments." Water Resources Research 49(2):1163-1177.  doi:10.1002/wrcr.20104
  • Wallin EL, TC Johnson, WJ Greenwood, and JM Zachara. 2013. "Imaging high stage river-water intrusion into a contaminated aquifer along a major river corridor using 2D time-lapse surface electrical resistivity tomography." Water Resources Research 49(3):1693-1708.  doi:10.1002/wrcr.20119
  • White GF, Z Shi, L Shi, Z Wang, A Dohnalkova, MJ Marshall, JK Fredrickson, JM Zachara, JN Butt, D Richardson, and TA Clarke. 2013. "Rapid electron exchange between surface-exposed bacterial cytochromes and Fe(III) minerals." Proceedings of the National Academy of Sciences of the United States of America 110(16):6346-6351.  doi:10.1073/pnas.1220074110
  • Zachara JM, ES Ilton, and C Liu. 2013. "Reactive Transport of the Uranyl Ion in Soils, Sediments, and Groundwater Systems." Chapter 8 in Uranium - Cradle to Grave. Short Course Series, vol. 43, ed. PC Burns and GE Sigmon, pp. 255-299.  Mineralogical Association of Canada, Quebec, PQ, Canada. 
  • Zachara JM, PE Long, J Bargar, JA Davis, PM Fox, JK Fredrickson, MD Freshley, A Konopka, C Liu, JP McKinley, ML Rockhold, KH Williams, and SB Yabusaki. 2013. "Persistence of uranium groundwater plumes: Contrasting mechanisms at two DOE sites in the groundwater-river interaction zone." Journal of Contaminant Hydrology 147:45-72.  doi:10.1016/j.jconhyd.2013.02.001


  • Chen X, H Murakami, MS Hahn, GE Hammond, ML Rockhold, JM Zachara, and Y Rubin. 2012. "Three-Dimensional Bayesian Geostatistical Aquifer Characterization at the Hanford 300 Area using Tracer Test Data." Water Resources Research 48:Article No. W06501.  doi:10.1029/2011WR010675
  • Pearce CI, MJ Wilkins, C Zhang, SM Heald, JK Fredrickson, and JM Zachara. 2012. "Pore-Scale Characterization of Biogeochemical Controls on Iron and Uranium Speciation under Flow Conditions." Environmental Science & Technology 46(15):7992-8000.  doi:10.1021/es301050h
  • Shi Z, JM Zachara, L Shi, Z Wang, DA Moore, DW Kennedy, and JK Fredrickson. 2012. "Redox reactions of reduced flavin mononucleotide (FMN), riboflavin (RBF), and anthraquinone-2,6-disulfonate (AQDS) with ferrihydrite and lepidocrocite." Environmental Science & Technology 46(21):11644-11652.  doi:10.1021/es301544b
  • Zachara JM, MD Freshley, GV Last, RE Peterson, and BN Bjornstad. 2012. Updated Conceptual Model for the 300 Area Uranium Groundwater PlumePNNL-22048, Pacific Northwest National Laboratory, Richland, WA. 
  • Breuer M, PP Zarzycki, L Shi, T Clarke, M Edwards, JN Butt, DJ Richardson, JK Fredrickson, JM Zachara, J Blumberger, and KM Rosso. 2012. "Molecular Structure and Free Energy Landscape for Electron Transport in the Deca-Heme Cytochrome MtrF." Biochemical Society: Transactions 40(6):1198-1203.  doi:10.1042/BST20120139
  • Edwards M, A Hall, L Shi, JK Fredrickson, JM Zachara, JN Butt, D Richardson, and TA Clarke. 2012. "The Crystal Structure of the Extracellular 11-heme Cytochrome UndA Reveals a Conserved 10-heme Motif and Defined Binding Site for Soluble Iron Chelates." Structure 20(7):1275-1284.  doi:10.1016/j.str.2012.04.016
  • Edwards M, JK Fredrickson, JM Zachara, D Richardson, and TA Clarke. 2012. "Analysis of Structural MtrC Models Based on Homology with the Crystal Structure of MtrF." Biochemical Society: Transactions 40(6):1181-1185.  doi:10.1042/BST20120132
  • Johnson TC, RJ Versteeg, ML Rockhold, LD Slater, D Ntarlagiannis, WJ Greenwood, and JM Zachara. 2012. "Characterization of a contaminated wellfield using 3D electrical resistivity tomography implemented with geostatistical, discontinuous boundary, and known conductivity constraints." Geophysics 77(6):Article No. EN85.  doi:10.1190/geo2012-0121.1
  • Liu J, Z Wang, SM Belchik, M Edwards, C Liu, DW Kennedy, ED Merkley, MS Lipton, JN Butt, D Richardson, JM Zachara, JK Fredrickson, KM Rosso, and L Shi. 2012. "Identification and Characterization of MtoA: a Decaheme c-Type Cytochrome of the Neutrophilic Fe(II)-oxidizing Bacterium Sideroxydans lithotrophicus ES-1." Frontiers in Microbiological Chemistry 3:Article No. 37.  doi:10.3389/fmicb.2012.00037
  • Ma R, C Zheng, JM Zachara, and MJ Tonkin. 2012. "Utility of Bromide and Heat Tracers for Aquifer Characterization Affected by Highly Transient Flow Conditions." Water Resources Research 48(W08523 ):, doi:10.1029/2011WR011281
  • Marritt S, DG McMillan, L Shi, JK Fredrickson, JM Zachara, DJ Richardson, LJ Jeuken, and JN Butt. 2012. "The roles of CymA in support of the respiratory flexibility of Shewanella oneidensis MR-1." Biochemical Society: Transactions 40(6):1217-1221.  doi:10.1042/BST20120150
  • Marritt S, TG Lowe, J Bye, DG McMillan, L Shi, JK Fredrickson, JM Zachara, DJ Richardson, MR Cheesman, LJ Jeuken, and JN Butt. 2012. "A Functional Description of CymA, an Electron Transfer Hub Supporting Anaerobic Respiratory Flexibility in Shewanella." Biochemical Journal 444(3):465-474.  doi:10.1042/BJ20120197
  • Peretyazhko T, JM Zachara, RK Kukkadapu, SM Heald, IV Kutnyakov, CT Resch, BW Arey, CM Wang, L Kovarik, JL Phillips, and DA Moore. 2012. "Pertechnetate (TcO4-) reduction by reactive ferrous iron forms in naturally anoxic, redox transition zone sediments from the Hanford Site, USA." Geochimica et Cosmochimica Acta 92:48-66. 
  • Richardson D, JK Fredrickson, and JM Zachara. 2012. "Electron Transport at the Microbe-Mineral Interface: A Synthesis of Current Research Challenges." Biochemical Society: Transactions 40(6):1163-1166.  doi:10.1042/BST20120242
  • Richardson DJ, JN Butt, JK Fredrickson, JM Zachara, L Shi, MJ Edwards, GF White, N Baiden, AJ Gates, S Marritt, and TA Clarke. 2012. "The ‘porin-cytochrome’ model for microbe-to-mineral electron transfer." Molecular Microbiology 85(2):201-212.  doi:10.1111/j.1365-2958.2012.08088.x
  • Richardson DJ, M Edwards, GF White, N Baiden, RS Hartshorne, JK Fredrickson, L Shi, JM Zachara, AJ Gates, JN Butt, and T Clarke. 2012. "Exploring the biochemistry at the extracellular redox frontier of bacterial mineral Fe(III) respiration." Biochemical Society: Transactions 40(3):493-500. 
  • Sheng P, Q Hu, RP Ewing, C Liu, and JM Zachara. 2012. "Quantitative 3-D Elemental Mapping by LA-ICP-MS of a Basaltic Clast from the Hanford 300 Area, Washington, USA." Environmental Science & Technology 46(4):2025-2032.  doi:10.1021/es2023785
  • Shi L, KM Rosso, JM Zachara, and JK Fredrickson. 2012. "Mtr Extracellular Electron Transfer Pathways in Fe(III)-reducing or Fe(II)-oxidizing Bacteria: A Genomic Perspective." Biochemical Society: Transactions 40(6):1261-1267.  doi:10.1042/BST20120098
  • Shi L, KM Rosso, TA Clarke, DJ Richardson, JM Zachara, and JK Fredrickson. 2012. "Molecular Underpinnings of Fe(III) Oxide Reduction by Shewanella oneidensis MR-1." Frontiers in Microbiological Chemistry 3:Article No. 50.  doi:10.3389/fmicb.2012.00050
  • White GF, Z Shi, L Shi, A Dohnalkova, JK Fredrickson, JM Zachara, JN Butt, DJ Richardson, and T Clarke. 2012. "Development of a Proteoliposome Model to Probe Transmembrane Electron-Transfer Reactions." Biochemical Society: Transactions 40(6):1257-1260.  doi:10.1042/BST20120116
  • Zachara JM, BN Bjornstad, JN Christensen, MS Conrad, JK Fredrickson, MD Freshley, R Haggerty, GE Hammond, DB Kent, A Konopka, PC Lichtner, C Liu, JP McKinley, CJ Murray, ML Rockhold, Y Rubin, VR Vermeul, RJ Versteeg, and C Zheng. 2012. Multi-Scale Mass Transfer Processes Controlling Natural Attenuation and Engineered Remediation: An IFRC Focused on Hanford’s 300 Area Uranium Plume January 2011 to January 2012PNNL-21169, Pacific Northwest National Laboratory, Richland, WA. 


  • Shang J, C Liu, Z Wang, and JM Zachara. 2011. "Effect of Grain Size on Uranium(VI) Surface Complexation Kinetics and Adsorption Additivity." Environmental Science & Technology 45(14):6025-6031.  doi:10.1021/es200920k
  • Clarke TA, M Edwards, AJ Gates, A Hall, G White, J Bradley, CL Reardon, L Shi, AS Beliaev, MJ Marshall, Z Wang, N Watmough, JK Fredrickson, JM Zachara, JN Butt, and DJ Richardson. 2011. "Structure of a Bacterial Cell Surface Decaheme Electron Conduit." Proceedings of the National Academy of Sciences of the United States of America 108(23):9384-9389.  doi:10.1073/pnas.1017200108
  • Felmy AR, ES Ilton, KM Rosso, and JM Zachara. 2011. "Interfacial Reactivity of Radionuclides: Emerging Paradigms from Molecular Level Observations." Mineralogical Magazine 75(4):2379-2391. 
  • Greskowiak J, MB Hay, H Prommer, C Liu, V Post, R Ma, JA Davis, C Zheng, and JM Zachara. 2011. "Simulating adsorption of U(VI) under transient groundwater flow and hydrochemistry - Physical versus non-equilibrium model." Water Resources Research 47:Article No. W08501.  doi:10.1029/2010WR010118
  • Hay MB, DL Stoliker, JA Davis, and JM Zachara. 2011. "Characterization of the intragranular water regime within subsurface sediments: Pore volume, surface area, and mass transfer limitations." Water Resources Research 47:Article No. W10531.  doi:10.1029/2010WR010303
  • Liu C, J Shang, and JM Zachara. 2011. "Multispecies diffusion models: A study of uranyl species diffusion." Water Resources Research 47:W12514.  doi:10.1029/2011WR010575
  • Ma R, C Zheng, MJ Tonkin, and JM Zachara. 2011. "Importance of considering intraborehole flow in solute transport modeling under highly dynamic flow conditions ." Journal of Contaminant Hydrology 123(1-2):11-19.  doi:10.1016/j.jconhyd.2010.12.001
  • Plymale AE, JK Fredrickson, JM Zachara, A Dohnalkova, SM Heald, DA Moore, DW Kennedy, MJ Marshall, CM Wang, CT Resch, and P Nachimuthu. 2011. "Competitive Reduction of Pertechnetate (99TcO4-) by Dissimilatory Metal Reducing Bacteria and Biogenic Fe(II) ." Environmental Science & Technology 45(3):951-957. 
  • Shi L, SM Belchik, AE Plymale, SM Heald, A Dohnalkova, K Sybirna, H Bottin, TC Squier, JM Zachara, and JK Fredrickson. 2011. "Purification and Characterization of [NiFe]-Hydrogenase of Shewanella oneidensis MR-1." Applied and Environmental Microbiology 77(16):5584-5590. 
  • Shi L, SM Belchik, Z Wang, DW Kennedy, A Dohnalkova, MJ Marshall, JM Zachara, and JK Fredrickson. 2011. "Identification and Characterization of UndA-HRCR-6, an Outer Membrane Endecaheme c-Type Cytochrome of Shewanella sp. Strain HRCR-6 ." Applied and Environmental Microbiology 77(15):5521-5523.  doi:10.1128/AEM.00614-11
  • Stoliker DL, DB Kent, and JM Zachara. 2011. "Quantifying differences in the impact of variable chemistry on equilibrium uranium(VI) adsorption properties of aquifer sediments." Environmental Science & Technology 45(20):8733-8740.  doi:10.1021/es202677v
  • Wang Z, JM Zachara, JF Boily, Y Xia, CT Resch, DA Moore, and C Liu. 2011. "Determining Individual Mineral Contributions To U(VI) Adsorption In A Contaminated Aquifer Sediment: A Fluorescence Spectroscopy Study." Geochimica et Cosmochimica Acta 75(10):2965-2979. 
  • Yin J, R Haggerty, DL Stoliker, DB Kent, JD Istok, J Greskowiak, and JM Zachara. 2011. "Transient groundwater chemistry near a river: Effects on U(VI) transport in laboratory column experiments ." Water Resources Research 47:Article No. W04502.  doi:10.1029/2010WR009369
  • Zachara JM, BN Bjornstad, JN Christensen, MS Conrad, JK Fredrickson, MD Freshley, R Haggerty, GE Hammond, DB Kent, A Konopka, PC Lichtner, C Liu, JP McKinley, CJ Murray, ML Rockhold, Y Rubin, VR Vermeul, RJ Versteeg, AL Ward, and C Zheng. 2011. Multi-Scale Mass Transfer Processes Controlling Natural Attenuation and Engineered Remediation: An IFRC Focused on Hanford’s 300 Area Uranium Plume January 2010 to January 2011PNNL-20257, Pacific Northwest National Laboratory, Richland, WA. 
  • Zachara JM, RK Kukkadapu, T Peretyazhko, ME Bowden, CM Wang, DW Kennedy, DA Moore, and BW Arey. 2011. "The Mineralogic Transformation of Ferrihydrite Induced by Heterogeneous Reaction with Bioreduced Anthraquinone Disulfonate (AQDS) and the Role of Phosphate." Geochimica et Cosmochimica Acta 75(21):6330-6349.  doi:10.1016/j.gca.2011.06.030


  • Ilton ES, JM Zachara, DA Moore, JP McKinley, AD Eckberg, CL Cahill, and AR Felmy. 2010. "Dissolution study of Metatorbernite: Thermodynamic Properties and the effect of pH and Phosphate." Environmental Science & Technology 44(19):7521-7526.  doi:10.1021/es101619f
  • Liu C, L Zhong, and JM Zachara. 2010. "Uranium(VI) Diffusion in Low-Permeability Subsurface Materials." Radiochimica Acta 98(9-11):719-726.  doi:10.1524/ract.2010.1773
  • Boily JF, PL Gassman, T Peretyazhko, J Szanyi, and JM Zachara. 2010. "FTIR Spectral Components of Schwertmannite." Environmental Science & Technology 44(4):1185-1190. 
  • Greskowiak J, H Prommer, C Liu, V Post, R Ma, C Zheng, and JM Zachara. 2010. "Comparison of parameter sensitivities between a laboratory and field scale model of uranium transport in a dual domain, distributed-rate reactive system." Water Resources Research 46:Article No. W09509.  doi:10.1029/2009WR008781
  • Icenhower JP, N Qafoku, JM Zachara, and WJ Martin. 2010. "The Biogeochemistry of Technetium: A review of the behavior of an artificial element in the natural environment." American Journal of Science Vol. 310(8):721-752.  doi:10.2475/08.2010.02
  • Ma R, C Zheng, H Prommer, J Greskowiak, C Liu, JM Zachara, and ML Rockhold. 2010. "A Field-Scale Reactive Transport Model for U(VI) Migration Influenced by Coupled Multirate Mass Transfer and Surface Complexation Reactions." Water Resources Research 46:Art. No. W05509.  doi:10.1029/2009WR008168
  • Murakami H, X Chen, MS Hahn, Y Liu, ML Rockhold, VR Vermeul, JM Zachara, and Y Rubin. 2010. "Bayesian approach for three-dimensional aquifer characterization at the Hanford 300 Area." Hydrology and Earth System Sciences 14:1989-2001.  doi:10.5194/hess-14-1989-2010
  • Peretyazhko T, JM Zachara, DW Kennedy, JK Fredrickson, BW Arey, JP McKinley, CM Wang, A Dohnalkova, and Y Xia. 2010. "Ferrous Phosphate Surface Precipitates Resulting from the Reduction of Intragrain 6-line Ferrihydrite by Shewanella oneidensis MR-1 ." Geochimica et Cosmochimica Acta 74(13):3751-3767.  doi:10.1016/j.gca.2010.04.008
  • Peretyazhko T, JM Zachara, DW Kennedy, JK Fredrickson, BW Arey, JP McKinley, CM Wang, A Dohnalkova, and Y Xia. 2010. "Ferrous phosphate surface precipitates resulting from the reduction of intragrain 6-line ferrihydrite by Shewanella oneidensis MR-1." Geochimica et Cosmochimica Acta 74(13):3751-3767.  doi:10.1016/j.gca.2010.04.008
  • Reardon CL, A Dohnalkova, P Nachimuthu, DW Kennedy, D Saffarini, BW Arey, L Shi, Z Wang, DA Moore, JS Mclean, DM Moyles, MJ Marshall, JM Zachara, JK Fredrickson, and AS Beliaev. 2010. "Role of Outer-Membrane Cytochromes MtrC and OmcA in the Biomineralization of Ferrihydrite by Shewanella oneidensis MR-1." Geobiology 8(1):56-68.  doi:10.1111/j.1472-4669.2009.00226.x
  • 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. 
  • Vermeul VR, JP McKinley, DR Newcomer, RD Mackley, and JM Zachara. 2010. "River-Induced Flow Dynamics in Long-Screen Wells and Impact on Aqueous Samples." Ground Water 49(4):515-524.  doi:10.1111/j.1745-6584.2010.00769.x
  • Zachara JM, BN Bjornstad, JN Christensen, ME Conrad, JK Fredrickson, MD Freshley, R Haggerty, G Hammon, DB Kent, A Konopka, PC Lichtner, C Liu, JP McKinley, CJ Murray, ML Rockhold, Y Rubin, VR Vermeul, RJ Versteeg, AL Ward, and C Zheng. 2010. Multi-Scale Mass Transfer Processes Controlling Natural Attenuation and Engineered Remediation: An IFRC Focused on Hanford’s 300 Area Uranium PlumePNNL-19209, Pacific Northwest National Laboratory, Richland, WA. 


  • Liu C, JM Zachara, L Zhong, SM Heald, Z Wang, BH Jeon, and JK Fredrickson. 2009. "Microbial Reduction of Intragrain U(VI) in Contaminated Sediment." Environmental Science & Technology 43(13):4928-4933.  doi:10.1021/es8029208
  • Liu C, Z Shi, and JM Zachara. 2009. "Kinetics of Uranium(VI) Desorption from Contaminated Sediments: Effect of Geochemical Conditions and Model Evaluation ." Environmental Science & Technology 43(17):6560-6566. 
  • Marshall MJ, A Dohnalkova, DW Kennedy, AE Plymale, SH Thomas, FE Loffler, R Sanford, JM Zachara, JK Fredrickson, and AS Beliaev. 2009. "Electron donor-dependent radionuclide reduction and nanoparticle formation by Anaeromyxobacter dehalogenans strain 2CP-C." Environmental Microbiology 11(2):534-543. 
  • Fredrickson JK, JM Zachara, AE Plymale, SM Heald, JP McKinley, DW Kennedy, C Liu, and P Nachimuthu. 2009. "Oxidative Dissolution Potential of Biogenic and Abiogenic TcO2 in Subsurface Sediments." Geochimica et Cosmochimica Acta 73(8):962-976.  doi:10.1016/j.gca.2009.01.027
  • Hartshorne RS, CL Reardon, DE Ross, J Nuester, TA Clarke, AJ Gates, PC Mills, JK Fredrickson, JM Zachara, L Shi, AS Beliaev, MJ Marshall, M Tien, SL Brantley, JN Butt, and D Richardson. 2009. "Characterization of an electron conduit between bacteria and the extracellular environment." Proceedings of the National Academy of Sciences of the United States of America 106(52):22169-22174.  doi:10.1073/pnas.0900086106
  • Jaisi DP, H Dong, AE Plymale, JK Fredrickson, JM Zachara, S Heald, and C Liu. 2009. "Reduction and long-term immobilization of technetium by Fe(II) associated with clay mineral nontronite ." Chemical Geology 264(1-4):127-138.  doi:10.1016/j.chemgeo.2009.02.018
  • Peretyazhko T, JM Zachara, JF Boily, Y Xia, PL Gassman, BW Arey, and WD Burgos. 2009. "Mineralogical transformations controlling acid mine drainage chemistry." Chemical Geology 262(3-4):169-178. 
  • Pierce EM, MD Freshley, SS Hubbard, BB Looney, JM Zachara, L Liang, D Lesmes, GM Chamberlain, KL Skubal, V Adams, ME Denham, and DM Wellman. 2009. Scientific Opportunity to Reduce Risk in Groundwater and Soil RemediationPNNL-18516, Pacific Northwest National Laboratory, Richland, WA. 
  • Shi L, D Richardson, Z Wang, SN Kerisit, KM Rosso, JM Zachara, and JK Fredrickson. 2009. "The Roles of Outer Membrane Cytochromes of Shewanella and Geobacter in Extracellular Electron Transfer." Environmental Microbiology Reports 1(4):220-227.  doi:10.1111/j.1758-2229.2009.00035.x
  • Shi Z, C Liu, JM Zachara, Z Wang, and B Deng. 2009. "Inhibition Effect of Secondary Phosphate Mineral Precipitation on Uranium Release from Contaminated Sediments." Environmental Science & Technology 43(21):8344-8349.  doi:10.1021/es9021359
  • Singer DM, JM Zachara, and GE Brown, JR. 2009. "Uranium Speciation As a Function of Depth in Contaminated Hanford Sediments - A Micro-XRF, Micro-XRD, and Micro- And Bulk-XAFS Study ." Environmental Science & Technology 43(3):630-636. 
  • Stubbs JE, LA Veblen, D Elbert, JM Zachara, JA Davis, and DR Veblen. 2009. "Newly recognized hosts for uranium in the Hanford Site vadose zone." Geochimica et Cosmochimica Acta 73(6):1563-1576. 


  • Ilton ES, N Qafoku, C Liu, DA Moore, and JM Zachara. 2008. "Advective Removal of Intraparticle Uranium from Contaminated Vadose Zone Sediments, Hanford, USA." Environmental Science & Technology 42(5):1565-1571.  doi:10.1021/es071113m
  • Marshall MJ, AE Plymale, DW Kennedy, L Shi, Z Wang, SB Reed, A Dohnalkova, CJ Simonson, C Liu, D Saffarini, MF Romine, JM Zachara, AS Beliaev, and JK Fredrickson. 2008. "Hydrogenase- and Outer Membrane c-Type Cytochrome-Facilitated Reduction of Technetium(VII) by Shewanella oneidensis MR-1." Environmental Microbiology 10(1):125-136.  doi:10.1111/j.1462-2920.2007.01438.x
  • Peretyazhko T, JM Zachara, SM Heald, BH Jeon, RK Kukkadapu, C Liu, DA Moore, and CT Resch. 2008. "Heterogeneous Reduction of Tc(VII) by Fe(II) at the Solid-Water Interface." Geochimica et Cosmochimica Acta 72(6):1521-1539.  doi:10.1016/j.gca.2008.01.004
  • Peretyazhko T, JM Zachara, SM Heald, RK Kukkadapu, C Liu, AE Plymale, and CT Resch. 2008. "Reduction of Tc(VII) by Fe(II) Sorbed on Al (hydr)oxides." Environmental Science & Technology 42(15):5499-5506.  doi:10.1021/es8003156
  • Zachara JM, MD Freshley, and FM Mann. 2008. Science Road Map for Phase 2 of the Tank-Farm Vadose Zone ProgramPNNL-17684; RPP-PLAN-38191, Rev. 0, Pacific Northwest National Laboratory, Richland, WA. 
  • Bond DL, JA Davis, and JM Zachara. 2008. "Uranium(VI) Release from Contaminated Vadose Zone Sediments: Estimation of Potential Contributions from Dissolution and Desorption." Chapter 14 in Adsorption of Metals to Geomedia II, ed. MO Barnett, DB Kent, pp. 375-416.  Elsevier, Boston, MA. 
  • Cantrell KJ, RJ Serne, JM Zachara, KM Krupka, PE Dresel, CF Brown, and MD Freshley. 2008. "Appendix G: Geochemistry." In The Resource Conservation and Recovery Act Facility Investigation (RFI) Report for Hanford Single-Shell Tank Waste Management Areas, DOE/ORP-2008-01 Revision 0, vol. Tier 2, ed. FM Mann.  U.S. Department of Energy, Office of River Protection, Richland, WA. 
  • Clarke TA, T Holley, RS Hartshorne, JK Fredrickson, JM Zachara, L Shi, and D Richardson. 2008. "The role of multihaem cytochromes in the respiration of nitrite in Escherichia coli and Fe(III) in Shewanella oneidensis." Biochemical Society: Transactions 36(Pt. 5):1005-1010.  doi:10.1042/BST0361005
  • Fredrickson JK, and JM Zachara. 2008. "Electron Transfer at the Microbe-Mineral Interface: A Grand Challenge in Biogeochemistry." Geobiology 6(3):245-253. 
  • Icenhower JP, N Qafoku, WJ Martin, and JM Zachara. 2008. The Geochemistry of Technetium: A Summary of the Behavior of an Artificial Element in the Natural EnvironmentPNNL-18139, Pacific Northwest National Laboratory, Richland, WA. 
  • Liu C, JM Zachara, N Qafoku, and Z Wang. 2008. "Scale-dependent desorption of uranium from contaminated subsurface sediments." Water Resources Research 44:W08413.  doi:10.1029/2007WR006478
  • Serne RJ, BN Bjornstad, HT Schaef, BA Williams, DC Lanigan, DG Horton, RE Clayton, AV Mitroshkov, VL Legore, MJ O'Hara, CF Brown, KE Parker, IV Kutnyakov, JN Serne, GV Last, SC Smith, CW Lindenmeier, JM Zachara, and DS Burke. 2008. Characterization of Vadose Zone Sediment: Uncontaminated RCRA Borehole Core Samples and Composite SamplesPNNL-13757-1 Rev. 1, Pacific Northwest National Laboratory, Richland, WA. 
  • Shi L, S Deng, MJ Marshall, Z Wang, DW Kennedy, A Dohnalkova, HM Mottaz, EA Hill, YA Gorby, AS Beliaev, DJ Richardson, JM Zachara, and JK Fredrickson. 2008. " Direct Involvement of Type II Secretion System in Extracellular Translocation of Shewanella Oneidensis Outer Membrane Cytochromes MtrC and OmcA." Journal of Bacteriology 190(15):5512-5516.  doi:10.1128/JB.00514-08
  • Wang Z, C Liu, X Wang, MJ Marshall, JM Zachara, KM Rosso, M Dupuis, JK Fredrickson, SM Heald, and L Shi. 2008. "Kinetics of Reduction of Fe(III) Complexes by Outer Membrane Cytochromes MtrC and OmcA of Shewanella oneidensis MR-1." Applied and Environmental Microbiology 74(21):6746-6755.  doi:10.1128/AEM.01454-08
  • Wang Z, JM Zachara, C Liu, PL Gassman, AR Felmy, and SB Clark. 2008. "A cryogenic fluorescence spectroscopic study of uranyl carbonate, phosphate, and oxyhydroxide minerals." Radiochimica Acta 96(9-11):591-598.  doi:10.1524/ract.2008.1541
  • Wellman DM, JM Zachara, C Liu, N Qafoku, SC Smith, and SW Forrester. 2008. "Advective Desorption of Uranium (VI) from Contaminated Hanford Vadose Zone Sediments under Saturated and Unsaturated Conditions." Vadose Zone Journal 7(4):1144-1159.  doi:10.2136/vzj2007.0166


  • Liu C, BH Jeon, JM Zachara, and Z Wang. 2007. "Influence of Calcium on Microbial Reduction of Solid Phase Uranium (VI)." Biotechnology and Bioengineering 97(6):1415-1422.  doi:10.1002/bit.21357
  • Liu C, JM Zachara, NS Foster, and J Strickland. 2007. "Kinetics of Reductive Dissolution of Hematite by Bioreduced Anthraquinone-2,6-disulfate." Environmental Science & Technology 41(22):7730-7735.  doi:10.1021/es070768k
  • Zachara JM, RJ Serne, MD Freshley, FM Mann, FJ Anderson, MI Wood, TE Jones, and DA Myers. 2007. "Geochemical Processes Controlling Migration of High Level Wastes in Hanford's Vadose Zone." Vadose Zone Journal 6(4):985-1003.  doi:10.2136/vzj2006.0180
  • Arai Y, MA Marcus, N Tamura, JA Davis, and JM Zachara. 2007. "Spectroscopic Evidence for Uranium Bearing Precipitates in Vadose Zone Sediments at the Hanford 300-Area Site." Environmental Science & Technology 41(13):4633-4639. 
  • Cantrell KJ, JM Zachara, PE Dresel, KM Krupka, and RJ Serne. 2007. Geochemical Processes Data Package for the Vadose Zone in the Single-Shell Tank Waste Management Areas at the Hanford SitePNNL-16663, Pacific Northwest National Laboratory, Richland, WA. 
  • Gee GW, M Oostrom, MD Freshley, ML Rockhold, and JM Zachara. 2007. "Hanford Site Vadose-Zone Studies: An Overview." Vadose Zone Journal 6(4):899-905.  doi:10.2136/vzj2006.0179
  • Hartshorne RS, BN Jepson, TA Clarke, SJ Field, JK Fredrickson, JM Zachara, L Shi, JN Butt, and D Richardson. 2007. "Characterization of Shewanella oneidensis MtrC: a cell-surface decaheme cytochrome involved in respiratory electron transport to extracellular electron acceptors." Journal of Biological Inorganic Chemistry 12(7):1083-1094.  doi:10.1007/s00775-007-0278-y
  • Heald SM, JM Zachara, BH Jeon, JP McKinley, RK Kukkadapu, and DA Moore. 2007. "XAFS Study of the Chemical and Structural States of Technetium in Fe(III) Oxide Co-precipitates." In X-RAY Absorption Fine Structure - XAFS13: 13th International Conference. AIP Conference Proceedings, vol. 882, pp. 173-175.  American Institute of Physics, Melville, NY.  doi:10.1063/1.2644465
  • Komlos J, Jr., RK Kukkadapu, JM Zachara, and PR Jaffe. 2007. "Biostimulation of Iron Reduction and Subsequent Oxidation of Sediment Containing Fe-silicates and Fe-oxides: Effect of Redox Cycling on Fe(III) Bioreduction." Water Research 41(13):2996-3004.  doi:10.1016/j.watres.2007.03.019
  • McKinley JP, JM Zachara, J Wan, DE Mccready, and SM Heald. 2007. "Geochemical Controls on Contaminant Uranium in Vadose Hanford Formation Sediments at the 200 Area and 300 Area, Hanford Site, Washington." Vadose Zone Journal 6(4):1004-1017.  doi:10.2136/vzj2006.0184
  • McKinley JP, JM Zachara, SC Smith, and C Liu. 2007. "Cation exchange reactions controlling desorption of Sr-90(2+) from coarse-grained contaminated sediments at the Hanford site, Washington." Geochimica et Cosmochimica Acta 71(2):305-325. 
  • Shi L, TC Squier, JM Zachara, and JK Fredrickson. 2007. "Respiration of metal (hydr)oxides by Shewanella and Geobacter: a key role for multihaem c-type cytochromes." Molecular Microbiology 65(1):12-20.  doi:10.1111/j.1365-2958.2007.05783.x
  • 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. 
  • Zachara JM, JK Fredrickson, RK Kukkadapu, and YA Gorby. 2007. "Anaerobic Microbial-Mineral Processes with Fe(III) Oxides: Experimental Considerations and Approaches." Chapter 4 in Methods for Investigating Microbial-Mineral Interactions: CMS Workshop Lectures, vol. 14, ed. Patricia A. Maurice and Leslie A. Warren, pp. 117-165.  The Clay Minerals Society, West Lafayette, IN. 
  • Zachara JM, SM Heald, BH Jeon, RK Kukkadapu, C Liu, JP McKinley, A Dohnalkova, and DA Moore. 2007. "Reduction of Pertechnetate [Tc(VII)] by Aqueous Fe(II) and the Nature of Solid Phase Redox Products." Geochimica et Cosmochimica Acta 71(9):2137-2157.  doi:doi:10.1016/j.gca.2006.10.025


  • Ilton ES, C Liu, W Yantasee, Z Wang, DA Moore, AR Felmy, and JM Zachara. 2006. "The Dissolution of Synthetic Na-Boltwoodite in Sodium Carbonate Solutions." Geochimica et Cosmochimica Acta 70(19):4836-4849.  doi:10.1016/j.gca.2006.06.1553
  • Kukkadapu RK, JM Zachara, JK Fredrickson, JP McKinley, DW Kennedy, SC Smith, and H Dong. 2006. "Reductive Biotransformation of Fe in Shale-Limestone Saprolite Containing Fe(III) Oxides and Fe(II)/Fe(III) Phyllosilicates." Geochimica et Cosmochimica Acta 70(14):3662-3676.  doi:10.1016/j.gca.2006.05.004
  • Marshall MJ, AS Beliaev, A Dohnalkova, DW Kennedy, L Shi, Z Wang, MI Boyanov, B Lai, KM Kemner, JS Mclean, SB Reed, DE Culley, VL Bailey, CJ Simonson, D Saffarini, MF Romine, JM Zachara, and JK Fredrickson. 2006. "c-Type Cytochrome-Dependent Formation of U(IV) Nanoparticles by Shewanella oneidensis ." PloS Biology 4(8):1324-1333. 
  • Catalano JG, JP McKinley, JM Zachara, SM Heald, SC Smith, and GE Brown, JR. 2006. "Changes in Uranium Speciation through a Depth Sequence of Contaminated Hanford Sediments." Environmental Science and Technology 40(8):2517-2524 . 
  • Chang H, GV Korshin, Z Wang, and JM Zachara. 2006. "Adsorption of Uranyl on Gibbsite: A Time-Resolved Laser-Induced Fluorescence Spectroscopy Study ." Environmental Science and Technology 40(4):1244-1249. 
  • Fox PM, JA Davis, and JM Zachara. 2006. "The Effect of Calcium on Aqueous Uranium (VI) Speciation and Adsorption to Ferrihydrite and Quartz." Geochimica et Cosmochimica Acta 70(6):1379-1387. 
  • Fox PM, JA Davis, and JM Zachara. 2006. "The effect of calcium on aqueous uranium(VI) speciation and adsorption to ferrihydrite and quartz." Geochimica et Cosmochimica Acta 70(6):1379-1387. 
  • Liu C, BH Jeon, JM Zachara, Z Wang, A Dohnalkova, and JK Fredrickson. 2006. "Kinetics of Microbial Reduction of Solid Phase U(VI)." Environmental Science and Technology 40(20):6290-6296. 
  • Liu C, JM Zachara, W Yantasee, PD Majors, and JP McKinley. 2006. "Microscopic Reactive Diffusion of Uranium in the Contaminated Sediments at Hanford, United States." Water Resources Research 42(W12420):1-15.  doi:10.1029/2006WR005031
  • McKinley JP, JM Zachara, C Liu, SM Heald, BI Prenitzer, and B Kempshall. 2006. "Microscale Controls on the Fate of Contaminant Uranium in the Vadose Zone, Hanford Site, Washington." Geochimica et Cosmochimica Acta 70(8):1873-1887 .  doi:10.1016/j.gca.2005.10.037
  • Shi L, B Chen, Z Wang, DA Elias, MU Mayer, YA Gorby, S Ni, BH Lower, DW Kennedy, DS Wunschel, HM Mottaz, MJ Marshall, EA Hill, AS Beliaev, JM Zachara, JK Fredrickson, and TC Squier. 2006. "Isolation of a High-Affinity Functional Protein Complex between OmcA and MtrC: Two Outer Membrane Decaheme c-type Cytochromes of Shewanella oneidensis MR-1 ." Journal of Bacteriology 188(13):4705-4714.  doi:10.1128/JB.01966-05
  • Xiong Y, L Shi, B Chen, MU Mayer, BH Lower, londer, S Bose, MF Hochella, Jr, JM Zachara, JK Fredrickson, and TC Squier. 2006. "High-Affinity Binding and Direct Electron Transfer to Solid Metals by the Shewanella oneidensis MR-1 Outer Membrane c-type Cytochrome OmcA." Journal of the American Chemical Society 128(43):13978-13979.  doi:10.1021/ja063526d


  • Liu C, JM Zachara, L Zhong, RK Kukkadapu, JE Szecsody, and DW Kennedy. 2005. "Influence of Sediment Bioreduction and Reoxidation on Uranium Sorption." Environmental Science and Technology 39(11):4125-4133. 
  • Wang Z, JM Zachara, JP McKinley, and SC Smith. 2005. "Cryogenic Laser Induced U(VI) Fluorescence Studies of a U(VI) Substituted Natural Calcite: Implications to U(VI) Speciation in Contaminated Hanford Sediments." Environmental Science and Technology 39:2651-2659. 
  • Ainsworth CC, JM Zachara, KB Wagnon, SG McKinley, C Liu, SC Smith, HT Schaef, and PL Gassman. 2005. "Impact of Highly Basic Solutions on Sorption of Cs+ to Subsurface Sediments from the Hanford Site, USA." Geochimica et Cosmochimica Acta 69(20):4787-4800. 
  • Dichristina TJ, JK Fredrickson, and JM Zachara. 2005. "Enzymology of Electron Transport: Energy Generation with Geochemical Consequences." Chapter 3 in Molecular Geomicrobiology, Reviews in Mineralogy & Geochemistry, vol. 59, ed. J.F. Banfield, J. Cervini-Silva and K.H. Nealson, pp. 27-52.  Mineralogical Society of America, Chantilly, VA. 
  • Dong W, WP Ball, C Liu, Z Wang, AT Stone, J Bai, and JM Zachara. 2005. "Influence of Calcite and Dissolved Calcium on Uranium(VI) Sorption to a Hanford Subsurface Sediment." Environmental Science and Technology 39(20):7949-7955.  doi:10.1021/es0505088
  • Kelly SD, KM Kemner, SC Brooks, JK Fredrickson, SL Carroll, DW Kennedy, JM Zachara, AE Plymale, and S Fendorf. 2005. "Ca-UO2-CO3 Complexation - Implications for Bioremediation of U(VI)." Physica Scripta T115:915-917.  doi:10.1238/Physica.Topical.115a00915
  • Kukkadapu RK, JM Zachara, JK Fredrickson, DW Kennedy, A Dohnalkova, and DE McCready. 2005. "Ferrous Hydroxy Carbonate is a Stable Transformation Product of Biogenic Magnetite." American Mineralogist 90(2-3):510-515. 
  • Peterson RE, EJ Freeman, PD Thorne, MD Williams, JW Lindberg, CJ Murray, MJ Truex, SB Yabusaki, JP McDonald, VR Vermeul, and JM Zachara. 2005. Contaminants of Potential Concern in the 300-FF-5 Operable Unit: Expanded Annual Groundwater Report for Fiscal Year 2004PNNL-15127, Pacific Northwest National Laboratory, Richland, WA. 
  • Qafoku N, JM Zachara, C Liu, PL Gassman, O Qafoku, and SC Smith. 2005. "Kinetic Desorption and Sorption of U(VI) During Reactive Transport in a Contaminated Hanford Sediment." Environmental Science and Technology 39(9):3157-3165.  doi:10.1021/es048462q
  • Wang Z, JM Zachara, PL Gassman, C Liu, O Qafoku, W Yantasee, and JG Catalano. 2005. "Fluorescence Spectroscopy of U(VI)-Silicates and U(VI)-Contaminated Hanford Sediment." Geochimica et Cosmochimica Acta 69(6):1391-1403.  doi:10.1016/j.gca.2004.08.028
  • Zachara JM, JA Davis, C Liu, JP McKinley, N Qafoku, DM Wellman, and SB Yabusaki. 2005. Uranium Geochemistry in Vadose Zone and Aquifer Sediments from the 300 Area Uranium PlumePNNL-15121, Pacific Northwest National Laboratory, Richland, WA. 
  • Zhong L, C Liu, JM Zachara, DW Kennedy, JE Szecsody, and BD Wood. 2005. "Oxidative Remobilization of Biogenic Uranium (IV) Precipitates: Effects of Iron (II) and pH." Journal of Environmental Quality 34(5):1763-1771. 


  • Kukkadapu RK, JM Zachara, JK Fredrickson, and DW Kennedy. 2004. "Biotransformation of Two-Line Silica-Ferrihydrite by a Dissimilatory Fe(III)-Reducing Bacterium: Formation of Carbonate Green Rust in the Presence of Phosphate." Geochimica et Cosmochimica Acta 68(13):2799-2814. 
  • Liu C, JM Zachara, and SC Smith. 2004. "A Cation Exchange Model to Describe Cs+ Sorption at High Ionic Strength in Subsurface Sediments at Hanford Site, USA." Journal of Contaminant Hydrology 68(3-4):217-238. 
  • Liu C, JM Zachara, AR Felmy, and YA Gorby. 2004. "An Electrodynamics-Based Model for Ion Diffusion in Microbial Polysaccharides." Colloids and Surfaces. B, Biointerfaces 38:55-65. 
  • Catalano JG, SM Heald, JM Zachara, and GE Brown Jr.. 2004. "Spectroscopic and Diffraction Study of Uranium Speciation in Contaminated Vadose Zone Sediments from the Hanford Site, Washington State." Environmental Science and Technology 38(10):2822-2828. 
  • Fredrickson JK, JM Zachara, DL Balkwill, DW Kennedy, SMW Li, HM Kostandarithes, MJ Daly, MF Romine, and FJ Brockman. 2004. "Geomicrobiology of High Level Nuclear Waste-Contaminated Vadose Sediments at the Hanford Site, Washington State." Applied and Environmental Microbiology 70(7):4230-4241. 
  • Fredrickson JK, JM Zachara, DW Kennedy, RK Kukkadapu, JP McKinley, SM Heald, C Liu, and AE Plymale. 2004. "Reduction of TcO4- by sediment-associated biogenic Fe(II)." Geochimica et Cosmochimica Acta 68(15):3171-3187. 
  • Liu C, JM Zachara, O Qafoku, JP McKinley, SM Heald, and Z Wang. 2004. "Dissolution of Uranyl Microprecipitates from Subsurface Sediments at Hanford Site, USA." Geochimica et Cosmochimica Acta 68(22):4519-4537. 
  • McKinley JP, JM Zachara, SM Heald, A Dohnalkova, M Newville, and SR Sutton . 2004. "Microscale Distribution of Cesium Sorbed to Biotite and Muscovite." Environmental Science and Technology 38(4):1017-1023. 
  • Wang Z, JM Zachara, W Yantasee, PL Gassman, C Liu, and AG Joly. 2004. "Cryogenic Laser Induced Fluorescence Characterization of U(VI) in Hanford Vadose Zone Pore Waters." Environmental Science and Technology 38:5591-5597. 
  • Zachara JM, CC Ainsworth, GE Brown, JR, JG Catalano, JP McKinley, O Qafoku, SC Smith, JE Szecsody, SJ Traina, and JA Warner. 2004. "Chromium Speciation and Mobility in a High Level Nuclear Waste Vadose Zone Plume." Geochimica et Cosmochimica Acta 68(1):13-30. 
  • Zachara JM, RK Kukkadapu, PL Gassman, A Dohnalkova, JK Fredrickson, and T Anderson. 2004. "Biogeochemical Transformation of Fe Minerals in a Petroleum-Contaminated Aquifer." Geochimica et Cosmochimica Acta 68(8):1791-1805. 


  • Liu C, JM Zachara, SC Smith, JP McKinley, and CC Ainsworth. 2003. "Desorption Kinetics of Radiocesium from Subsurface Sediments at Hanford Site, USA." Geochimica et Cosmochimica Acta 67(16):2893-2912. 
  • Rosso KM, JM Zachara, JK Fredrickson, YA Gorby, and SC Smith. 2003. "Nonlocal Bacterial Electron Transfer to Hematite Surfaces." Geochimica et Cosmochimica Acta 67(5):1081-1087. 
  • Brooks SC, JK Fredrickson, SL Carroll, DW Kennedy, JM Zachara, AE Plymale, SD Kelly, KM Kemner, and S Fendorf. 2003. "Inhibition of bacterial U(VI) reduction by calcium." Environmental Science and Technology 37(9):1850-1858. 
  • Dong H, RK Kukkadapu, JK Fredrickson, JM Zachara, DW Kennedy, and HM Kostandarithes. 2003. "Microbial Reduction of Structural Fe(III) in Illite and Goethite." Environmental Science and Technology Vol. 37(7):1268-1276 . 
  • Fredrickson JK, S Kota, RK Kukkadapu, C Liu, and JM Zachara. 2003. "Influence of Electron Donor/Acceptor Concentrations on Hydrous Ferric Oxide (HFO) Bioreduction." Biodegradation 14(2):91-103. 
  • Kukkadapu RK, JM Zachara, JK Fredrickson, SC Smith, A Dohnalkova, and CK Russell. 2003. "Transformation of 2-line Ferrihydrite to 6-line Ferrihydrite under Oxic and Anoxic Conditions." American Mineralogist 88(11-12):1903-1914 pt. 2. 
  • Liu C, JM Zachara, O Qafoku, and SC Smith. 2003. "Effect of Temperature on Cs+ Sorption and Desorption in Subsurface Sediments at Hanford Site, U.S.A." Environmental Science and Technology 37(12):2640-2645. 
  • Mayes MA, PM Jardine, TL Mehlhorn, BN Bjornstad, JL Ladd, and JM Zachara. 2003. "Transport of Multiple Tracers in Variably Saturated Humid Region Structured Soils and Semi-arid Region Laminated Sediments." Journal of Hydrology 275(3-4):141-161. 
  • Pace MN, MA Mayes, PM Jardine, TL Mehlhorn, JM Zachara, and BN Bjornstad. 2003. "Quantifying the effects of small-scale heterogeneities on flow and transport in undisturbed cores from the Hanford formation." Vadose Zone Journal 2(4):664-676. 


  • Liu C, YA Gorby, JM Zachara, JK Fredrickson, and CF Brown. 2002. "Reduction Kinetics of Fe(III), Co(III), U(VI), Cr(VI), and Tc(VII) in Cultures of Dissimilatory Metal-reducing Bacteria." Biotechnology and Bioenegineering 80(6):637-649. 
  • Bredt PR, CC Ainsworth, FJ Brockman, DM Camaioni, OB Egorov, AR Felmy, YA Gorby, JW Grate, MS Greenwood, BP Hay, NJ Hess, TL Hubler, JP Icenhower, SV Mattigod, BP McGrail, PD Meyer, CJ Murray, PD Panetta, DM Pfund, D Rai, Y Su, SK Sundaram, WJ Weber, and JM Zachara. 2002. Science to Support DOE Site Cleanup: The Pacific Northwest National Laboratory Environmental Management Science Program Awards -- Fiscal Year 2002 Mid-Year Progress ReportPNNL-13928, Pacific Northwest National Laboratory, Richland, WA. 
  • Fredrickson JK, JM Zachara, DW Kennedy, C Liu, MC Duff, D Hunter, and A Dohnalkova. 2002. "Influence of Mn oxides on the reduction of U(VI) by the metal-reducing bacterium Shewanella putrefaciens." Geochimica et Cosmochimica Acta 66(18):3247-3262. 
  • Freshley MD, JM Zachara, and MJ Graham. 2002. "Implementation of the Hanford Science and Technology Roadmap." In Waste Management 2002: Proceedings of the Symposium on Waste Management, February 24-28, Tucson, AZ, p. 8 pages.  Arizona Board of Regents, Tucson, AZ. 
  • Freshley MD, AL Bunn, GW Gee, TJ Gilmore, CT Kincaid, RE Peterson, AL Ward, SB Yabusaki, and JM Zachara. 2002. Groundwater Protection Program Science and Technology Summary DescriptionPNNL-14092, Pacific Northwest National Laboratory, Richland, WA. 
  • Liu C, JM Zachara, JK Fredrickson, DW Kennedy, and A Dohnalkova. 2002. "Modeling the Inhibition of the Bacterial Reduction of U(VI) by beta-MnO2(S)(g)." Environmental Science and Technology 36(7):1452-1459. 
  • Serne RJ, BN Bjornstad, HT Schaef, BA Williams, DC Lanigan, DG Horton, RE Clayton, AV Mitroshkov, VL Legore, MJ O'Hara, CF Brown, KE Parker, IV Kutnyakov, JN Serne, GV Last, SC Smith, CW Lindenmeier, JM Zachara, and DS Burke. 2002. Characterization of Vadose Zone Sediment: Uncontaminated RCRA Borehole Core Samples and Composite SamplesPNNL-13757-1, Pacific Northwest National Laboratory, Richland, WA. 
  • Zachara JM, RK Kukkadapu, JK Fredrickson, YA Gorby, and SC Smith. 2002. "Biomineralization of Poorly Crystalline Fe(III) Oxides by Dissimilatory Metal Reducing Bacteria (DMRB)." Geomicrobiology Journal 19:179-207. 
  • Zachara JM, SC Smith, C Liu, JP McKinley, RJ Serne, and PL Gassman. 2002. "Sorption of Cs+ to Micaceous Subsurface Sediments from the Hanford Site, USA." Geochimica et Cosmochimica Acta 66(2):193-211. 


  • Liu C, and JM Zachara. 2001. "Uncertainties of Monod Kinetic Parameters Nonlinearly Estimated from Batch Experiments." Environmental Science and Technology 35(1):133-141. 
  • Liu C, JM Zachara, YA Gorby, JE Szecsody, and CF Brown. 2001. "Microbial Reduction of Fe(III) and Sorption/Precipitation of Fe(II) on Shewanella putrefaciens Strain CN32." Environmental Science and Technology 35(7):1385-1393. 
  • Liu C, S Kota, JM Zachara, JK Fredrickson, and CK Brinkman. 2001. "Kinetic Analysis of the Bacterial Reduction of Goethite." Environmental Science and Technology 35:2482-2490. 
  • Zachara JM, JK Fredrickson, SC Smith, and PL Gassman. 2001. "Solubilization of Fe(III) Oxide-Bound Trace Metals by a Dissimilatory Fe(III) Reducing Bacterium." Geochimica et Cosmochimica Acta 65(1):75-93. 
  • Bredt PR, FJ Brockman, DM Camaioni, AR Felmy, JW Grate, BP Hay, NJ Hess, PD Meyer, CJ Murray, DM Pfund, Y Su, EC Thornton, WJ Weber, and JM Zachara. 2001. Science To Support DOE Site Cleanup: The Pacific Northwest National Laboratory Environmental Management Science Program AwardsPNNL-13564, Pacific Northwest National Laboratory, Richland, WA. 
  • Fredrickson JK, JM Zachara, RK Kukkadapu, YA Gorby, SC Smith, and CF Brown. 2001. "Biotransformation of Ni-Substituted Hydrous Ferric Oxide by an Fe(III)-Reducing Bacterium." Environmental Science and Technology 35(4):703-712. 
  • Kukkadapu RK, JM Zachara, SC Smith, JK Fredrickson, and C Liu. 2001. "Dissimilatory Bacterial Reduction of Al-Substituted Goethite in Subsurface Sediments." Geochimica et Cosmochimica Acta 65(17):2913-2924. 
  • McKinley JP, CJ Zeissler, JM Zachara, RJ Serne, RM Lindstrom, HT Schaef, and RD Orr. 2001. "Distribution and Retention of 137Cs in Sediments at the Hanford Site, Washington." Environmental Science and Technology 35(17):3433-3441. 
  • Yeh GT, WD Burgos, and JM Zachara. 2001. "Modeling and Measuring Biogeochemical Reactions: System Consistency, Data Needs, and Rate Formulations." Advances in Environmental Research 5:219-237. 
  • Zachara JM, NS Foster, JE Amonette, EJ Bylaska, AR Felmy, PL Gassman, SM Heald, RK Kukkadapu, C Liu, MJ Mason, KM Rosso, CK Russell, JR Rustad, SC Smith, Z Wang, and TW Wietsma. 2001. Annual Report 2000 Environmental Dynamics and SimulationPNNL-13456, Pacific Northwest National Laboratory, Richland, WA. 


  • Liu C, JE Szecsody, JM Zachara, and WP Ball. 2000. "Use of the Generalized Integral Transform Method for Solving Equations of Solute Transport in Porous Media." Advances in Water Resources 23(5):483-492. 
  • Zachara JM, SC Smith, and JK Fredrickson. 2000. "The Effect of Biogenic Fe(II) on the Stability and Sorption of Co(II)EDTA2- to Goethite and a Subsurface Sediment." Geochimica et Cosmochimica Acta 64(8):1345-1362. 
  • Dong H, JK Fredrickson, DW Kennedy, JM Zachara, RK Kukkadapu, and TC Onstott. 2000. "Mineral Transformations Associated with the Microbial Reduction of Magnetite." Chemical Geology 169:299-318. 
  • Fredrickson JK, JM Zachara, DW Kennedy, YA Gorby, SMW Li, and KM Krupka. 2000. "Reduction of U(VI) in Goethite (a-FeOOH) Suspensions by a Dissimilatory Metal-Reducing Bacterium." Geochimica et Cosmochimica Acta 64:3085-3098. 
  • Zachara JM, NS Foster, JE Amonette, EJ Bylaska, AR Felmy, PL Gassman, SM Heald, RK Kukkadapu, C Liu, MJ Mason, KM Rosso, CK Russell, JR Rustad, SC Smith, Z Wang, and TW Wietsma. 2000. Annual Report 1999 Environmental Dynamics & Simulation PNNL-13206, Pacific Northwest National Laboratory, Richland, WA. 


  • Zachara JM, JK Fredrickson, SMW Li, DW Kennedy, SC Smith, and PL Gassman. 1998. "Bacterial Reduction of Crystalline Fe3+ Oxides in Single Phase Suspensions and Subsurface Materials." American Mineralogist 83(11-12):1426-1443. 
  • Szecsody JE, A Chilakapati, JM Zachara, and AL Garvin. 1998. "Influence of Iron Oxide Inclusion Shape on Co(II/III)EDTA Reactive Transport Through Spatially Heterogeneous Sediment." Water Resources Research 34(10):2501-2514. 

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