PNNL

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.

• 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.

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

• 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

• 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

2017

• Bisht G., M. Huang, T. Zhou, X. Chen, H. Dai, G. Hammond, and W. Riley, et al. 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, no. 12:4539-4562. PNNL-SA-123895. doi:10.5194/gmd-10-4539-2017
• Dai H., X. Chen, M. Ye, X. Song, and J.M. Zachara. 2017. "A Geostatistics-Informed Hierarchical Sensitivity Analysis Method for Complex Groundwater Flow and Transport Modeling." Water Resources Research 53, no. 5:4327-4343. PNNL-SA-120000. doi:10.1002/2016WR019756
• Hou Z., W.C. Nelson, J.C. Stegen, C.J. Murray, E.V. Arntzen, A.R. Crump, and D.W. Kennedy, et al. 2017. "Geochemical and Microbial Community Attributes in Relation to Hyporheic Zone Geological Facies." Scientific Reports 7. PNNL-SA-121286. doi:10.1038/s41598-017-12275-w
• Li M., Y. Gao, W. Qian, L. Shi, Y. Liu, W.C. Nelson, and C.D. Nicora, et al. 2017. "Targeted quantification of functional enzyme dynamics in environmental samples for microbially mediated biogeochemical processes." Environmental Microbiology Reports 9, no. 5:512-521. PNNL-SA-120732. doi:10.1111/1758-2229.12558
• Liu Y., C. Liu, W.C. Nelson, L. Shi, F. Xu, Y. Liu, and A. Yan, et al. 2017. "Effect of Water Chemistry and Hydrodynamics on Nitrogen Transformation and Microbial Community Functional Potential in Hyporheic Zone Sediment Columns." Environmental Science & Technology 51, no. 9:4877-4886. PNNL-SA-121316. doi:10.1021/acs.est.6b05018
• Song H., D.G. Thomas, J.C. Stegen, M. Li, C. Liu, X. Song, and X. Chen, et al. 2017. "Regulation-structured dynamic metabolic model provides a potential mechanism for delayed enzyme response in denitrification process." Frontiers in Microbiology 8. PNNL-SA-129317. doi:10.3389/fmicb.2017.01866
• Xu F., Y. Liu, J.M. Zachara, M.E. Bowden, D.W. Kennedy, A.E. Plymale, and C. Liu. 2017. "Redox transformation and reductive immobilization of Cr(VI) in Columbia River hyporheic zone sediments." Journal of Hydrology 555. PNNL-SA-130775. doi:10.1016/j.jhydrol.2017.10.016
• Zhou T., M. Huang, J. Bao, Z. Hou, E.V. Arntzen, R.D. Mackley, and A.R. Crump, et al. 2017. "A New Approach to Quantify Shallow Water Hydrologic Exchanges in a Large Regulated River Reach." Water 9, no. 9:703. PNNL-SA-123562. doi:10.3390/w9090703

2016

• Zachara J.M., J.J. Moran, C.T. Resch, S.R. Lindemann, A.R. Felmy, M.E. Bowden, and A.B. Cory, et al. 2016. "Geo- and Biogeochemical Processes in a Heliothermal Hypersaline Lake." Geochimica et Cosmochimica Acta 181. PNNL-SA-108309. doi:10.1016/j.gca.2016.02.001
• Zachara J.M., S.L. Brantley, J.D. Chorover, R.P. Ewing, S.N. Kerisit, C. Liu, and E. Perfect, et al. 2016. "Internal Domains of Natural Porous Media Revealed: Critical Locations for Transport, Storage, and Chemical Reaction." Environmental Science & Technology 50, no. 6:2811-2829. PNNL-SA-113657. doi:10.1021/acs.est.5b05015
• Zachara J.M., X. Chen, C.J. Murray, and G. Hammond. 2016. "River Stage Influences on Uranium Transport in a Hydrologically Dynamic Groundwater-Surface Water Transition Zone." Water Resources Research 52, no. 3:1568-1590. PNNL-SA-112480. doi:10.1002/2015WR018009

2015

• Johnson T.C., R. Versteeg, J.N. Thomle, G.E. Hammond, X. Chen, and J.M. 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, no. 8:6177-6196. PNNL-SA-103949. doi:10.1002/2014WR016129
• Liu C., Y. Liu, S.N. Kerisit, and J.M. Zachara. 2015. "Pore-Scale Process Coupling and Effective Surface Reaction Rates in Heterogeneous Subsurface Materials." Reviews in Mineralogy and Geochemistry 80, no. 1:191-216. PNNL-SA-106979. doi:10.2138/rmg.2015.80.06
• Liu Y., C. Liu, C. Zhang, X. Yang, and J.M. Zachara. 2015. "Pore and Continuum Scale Study of the Effect of Subgrid Transport Heterogeneity on Redox Reaction Rates." Geochimica et Cosmochimica Acta 163. PNNL-SA-105545. doi:10.1016/j.gca.2015.04.039
• Liu Y., C. Liu, R.K. Kukkadapu, J.P. McKinley, J.M. Zachara, A.E. Plymale, and M.D. Miller, et al. 2015. "99Tc(VII) Retardation, Reduction, and Redox Rate Scaling in Naturally Reduced Sediments." Environmental Science & Technology 49, no. 22:13403-13412. PNNL-SA-111587. doi:10.1021/acs.est.5b03273
• Liu Y., J.K. Fredrickson, J.M. 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. PNNL-SA-112781. doi:10.3389/fmicb.2015.01075
• Scheibe T.D., W.A. Perkins, M.C. Richmond, M.I. McKinley, P. Romero Gomez, M. Oostrom, and T.W. Wietsma, et al. 2015. "Pore-Scale and Multiscale Numerical Simulation of Flow and Transport in a Laboratory-Scale Column." Water Resources Research 51, no. 2:1023-1035. PNNL-SA-103382. doi:10.1002/2014WR015959
• Wang Z., Z. Shi, L. Shi, G.F. White, D.J. Richardson, T.A. Clarke, and J.K. Fredrickson, et al. 2015. "Effects of soluble flavin on heterogeneous electron transfer between surface-exposed bacterial cytochromes and iron oxides." Geochimica et Cosmochimica Acta 163. PNNL-SA-106251. doi:10.1016/j.gca.2015.03.039
• Yan S., Y. Liu, C. Liu, L. Shi, J. Shang, H. Shan, and J.M. Zachara, et al. 2015. "Nitrate bioreduction in redox-variable low permeability sediments." Science of the Total Environment539. PNNL-SA-105761. doi:10.1016/j.scitotenv.2015.08.122

2014

• Edwards M., N. Baiden, A. Johs, S. Tomanicek, L. Liang, L. Shi, and J.K. Fredrickson, et al. 2014. "The X-ray crystal structure of Shewanella oneidensis OmcA reveals new insight at the microbe-mineral interface." FEBS Letters 588, no. 10:1886-1890. PNNL-SA-102427. doi:10.1016/j.febslet.2014.04.013
• Lee J., J.M. Zachara, J.K. Fredrickson, S.M. Heald, J.P. McKinley, A.E. Plymale, and C.T. Resch, et al. 2014. "Fe(II)- and Sulfide-Facilitated Reduction of 99Tc(VII)O4- in Microbially Reduced Hyporheic Zone Sediments." Geochimica et Cosmochimica Acta 136. PNNL-SA-97893. doi:10.1016/j.gca.2013.08.017
• Liu C., J. Shang, H. Shan, and J.M. Zachara. 2014. "Effect of Subgrid Heterogeneity on Scaling Geochemical and Biogeochemical Reactions: A Case of U(VI) Desorption." Environmental Science & Technology 48, no. 3:1745-1752. PNNL-SA-98535. doi:10.1021/es404224j
• Liu Y., Z. Wang, J. Liu, C. Levar, M. Edwards, J.T. Babauta, and D.W. Kennedy, et al. 2014. "A trans-outer membrane porin-cytochrome protein complex for extracellular electron transfer by Geobacter sulfurreducens PCA." Environmental Microbiology Reports 6, no. 6:776-785. PNNL-SA-104799. doi:10.1111/1758-2229.12204
• Ma R., C. Liu, J. Greskowiak, H. Prommer, J.M. Zachara, and C. Zheng. 2014. "Influence of calcite on uranium(VI) reactive transport in the groundwater-river mixing zone." Journal of Contaminant Hydrology 156. PNNL-SA-82994. doi:10.1016/j.jconhyd.2013.10.002
• Ma R., C. Zheng, C. Liu, J. Greskowiak, H. Prommer, and J.M. Zachara. 2014. "Assessment of Controlling Processes for Field-Scale Uranium Reactive Transport under Highly Transient Flow Conditions." Water Resources Research 50, no. 2:1006-1024. PNNL-SA-94004. doi:10.1002/2013WR013835
• Shang J., C. Liu, Z. Wang, and J.M. Zachara. 2014. "Long-term Kinetics of Uranyl Desorption from Sediments Under Advective Conditions." Water Resources Research 50, no. 2:855-870. PNNL-SA-94505. doi:10.1002/2013WR013949
• Shi L., J.K. Fredrickson, and J.M. Zachara. 2014. "Genomic Analyses of Bacterial Porin-Cytochrome Gene Clusters." Frontiers in Microbiology 5. PNNL-SA-106894. doi:10.3389/fmicb.2014.00657
• Wang Z., J.M. 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, no. 14:7766-7773. PNNL-SA-100708. doi:10.1021/es500537g

2013

• Chen X., G.E. Hammond, C.J. Murray, M.L. Rockhold, V.R. Vermeul, and J.M. Zachara. 2013. "Applications of Ensemble-based Data Assimilation Techniques for Aquifer Characterization using Tracer Data at Hanford 300 Area." Water Resources Research 49. PNNL-SA-91954. doi:10.1002/2012WR013285
• Liu C., J. Shang, S.N. Kerisit, J.M. Zachara, and W. Zhu. 2013. "Scale-Dependent Rates of Uranyl Surface Complexation Reaction in Sediments." Geochimica et Cosmochimica Acta105. PNNL-SA-75094. doi:10.1016/j.gca.2012.12.003
• Shi Z., J.M. Zachara, Z. Wang, L. Shi, and J.K. Fredrickson. 2013. "Reductive Dissolution of Goethite and Hematite by Reduced Flavins." Geochimica et Cosmochimica Acta 121. PNNL-SA-91506. doi:10.1016/j.gca.2013.05.039
• Stoliker D.L., C. Liu, D.B. Kent, and J.M. Zachara. 2013. "Characterizing particle-scale equilibrium adsorption and kinetics of uranium(VI) desorption from U-contaminated sediments." Water Resources Research 49, no. 2:1163-1177. PNNL-SA-88691. doi:10.1002/wrcr.20104
• Wallin E.L., T.C. Johnson, W.J. Greenwood, and J.M. 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, no. 3:1693-1708. PNNL-SA-88529. doi:10.1002/wrcr.20119
• White G.F., Z. Shi, L. Shi, Z. Wang, A. Dohnalkova, M.J. Marshall, and J.K. Fredrickson, et al. 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 America110, no. 16:6346-6351. PNNL-SA-94506. doi:10.1073/pnas.1220074110
• Zachara J.M., E.S. Ilton, and C. Liu. 2013. "Reactive Transport of the Uranyl Ion in Soils, Sediments, and Groundwater Systems." In Uranium - Cradle to Grave. Short Course Series, edited by PC Burns and GE Sigmon. 255-299. Quebec, :Mineralogical Association of Canada. PNNL-SA-94443.
• Zachara J.M., P.E. Long, J. Bargar, J.A. Davis, P.M. Fox, J.K. Fredrickson, and M.D. Freshley, et al. 2013. "Persistence of uranium groundwater plumes: Contrasting mechanisms at two DOE sites in the groundwater-river interaction zone." Journal of Contaminant Hydrology 147. PNNL-SA-88773. doi:10.1016/j.jconhyd.2013.02.001

2012

• Breuer M., P.P. Zarzycki, L. Shi, T. Clarke, M. Edwards, J.N. Butt, and D.J. Richardson, et al. 2012. "Molecular Structure and Free Energy Landscape for Electron Transport in the Deca-Heme Cytochrome MtrF." Biochemical Society: Transactions 40, no. 6:1198-1203. PNNL-SA-88376. doi:10.1042/BST20120139
• Chen X., H. Murakami, H. Murakami, M.S. Hahn, G.E. Hammond, M.L. Rockhold, and J.M. Zachara, et al. 2012. "Three-Dimensional Bayesian Geostatistical Aquifer Characterization at the Hanford 300 Area using Tracer Test Data." Water Resources Research 48. PNNL-SA-78432. doi:10.1029/2011WR010675
• Edwards M., A. Hall, L. Shi, J.K. Fredrickson, J.M. Zachara, J.N. Butt, and D. Richardson, et al. 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, no. 7:1275-1284. PNNL-SA-89780. doi:10.1016/j.str.2012.04.016
• Edwards M., J.K. Fredrickson, J.M. Zachara, D. Richardson, and T.A. Clarke. 2012. "Analysis of Structural MtrC Models Based on Homology with the Crystal Structure of MtrF." Biochemical Society: Transactions 40, no. 6:1181-1185. PNNL-SA-92979. doi:10.1042/BST20120132
• Johnson T.C., R.J. Versteeg, M.L. Rockhold, L.D. Slater, D. Ntarlagiannis, W.J. Greenwood, and J.M. Zachara. 2012. "Characterization of a contaminated wellfield using 3D electrical resistivity tomography implemented with geostatistical, discontinuous boundary, and known conductivity constraints." Geophysics 77, no. 6:EN85-EN96. PNNL-SA-86781. doi:10.1190/geo2012-0121.1
• Liu J., Z. Wang, S.M. Belchik, M. Edwards, C. Liu, D.W. Kennedy, and E.D. Merkley, et al. 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. PNNL-SA-83499. doi:10.3389/fmicb.2012.00037
• Ma R., C. Zheng, J.M. Zachara, and M.J. Tonkin. 2012. "Utility of Bromide and Heat Tracers for Aquifer Characterization Affected by Highly Transient Flow Conditions." Water Resources Research 48, no. W08523. PNNL-SA-91357. doi:10.1029/2011WR011281
• Marritt S., D.G. McMillan, L. Shi, J.K. Fredrickson, J.M. Zachara, D.J. Richardson, and L.J. Jeuken, et al. 2012. "The roles of CymA in support of the respiratory flexibility of Shewanella oneidensis MR-1." Biochemical Society: Transactions 40, no. 6:1217-1221. PNNL-SA-92636. doi:10.1042/BST20120150
• Marritt S., T.G. Lowe, J. Bye, D.G. McMillan, L. Shi, J.K. Fredrickson, and J.M. Zachara, et al. 2012. "A Functional Description of CymA, an Electron Transfer Hub Supporting Anaerobic Respiratory Flexibility in Shewanella." Biochemical Journal 444, no. 3:465-474. PNNL-SA-87065. doi:10.1042/BJ20120197
• Pearce C.I., M.J. Wilkins, C. Zhang, S.M. Heald, J.K. Fredrickson, and J.M. Zachara. 2012. "Pore-Scale Characterization of Biogeochemical Controls on Iron and Uranium Speciation under Flow Conditions." Environmental Science & Technology 46, no. 15:7992-8000. PNNL-SA-86518. doi:10.1021/es301050h
• Peretyazhko T., J.M. Zachara, R.K. Kukkadapu, S.M. Heald, I.V. Kutnyakov, C.T. Resch, and B.W. Arey, et al. 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. PNNL-SA-84692.
• Richardson D., J.K. Fredrickson, and J.M. Zachara. 2012. "Electron Transport at the Microbe-Mineral Interface: A Synthesis of Current Research Challenges." Biochemical Society: Transactions 40, no. 6:1163-1166. PNNL-SA-92980. doi:10.1042/BST20120242
• Richardson D.J., J.N. Butt, J.K. Fredrickson, J.M. Zachara, L. Shi, M.J. Edwards, and G.F. White, et al. 2012. "The ‘porin-cytochrome’ model for microbe-to-mineral electron transfer." Molecular Microbiology 85, no. 2:201-212. PNNL-SA-88922. doi:10.1111/j.1365-2958.2012.08088.x
• Richardson D.J., M. Edwards, G.F. White, N. Baiden, R.S. Hartshorne, J.K. Fredrickson, and L. Shi, et al. 2012. "Exploring the biochemistry at the extracellular redox frontier of bacterial mineral Fe(III) respiration." Biochemical Society: Transactions 40, no. 3:493-500. PNNL-SA-88013.
• Sheng P., Q. Hu, R.P. Ewing, C. Liu, and J.M. 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, no. 4:2025-2032. PNNL-SA-82891. doi:10.1021/es2023785
• Shi L., K.M. Rosso, J.M. Zachara, and J.K. Fredrickson. 2012. "Mtr Extracellular Electron Transfer Pathways in Fe(III)-reducing or Fe(II)-oxidizing Bacteria: A Genomic Perspective." Biochemical Society: Transactions 40, no. 6:1261-1267. PNNL-SA-86720. doi:10.1042/BST20120098
• Shi L., K.M. Rosso, T.A. Clarke, D.J. Richardson, J.M. Zachara, and J.K. Fredrickson. 2012. "Molecular Underpinnings of Fe(III) Oxide Reduction by Shewanella oneidensis MR-1." Frontiers in Microbiological Chemistry 3. PNNL-SA-83454. doi:10.3389/fmicb.2012.00050
• Shi Z., J.M. Zachara, L. Shi, Z. Wang, D.A. Moore, D.W. Kennedy, and J.K. 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, no. 21:11644-11652. PNNL-SA-87337. doi:10.1021/es301544b
• White G.F., Z. Shi, L. Shi, A. Dohnalkova, J.K. Fredrickson, J.M. Zachara, and J.N. Butt, et al. 2012. "Development of a Proteoliposome Model to Probe Transmembrane Electron-Transfer Reactions." Biochemical Society: Transactions 40, no. 6:1257-1260. PNNL-SA-88014. doi:10.1042/BST20120116
• Zachara J.M., B.N. Bjornstad, J.N. Christensen, M.S. Conrad, J.K. Fredrickson, M.D. Freshley, and R. Haggerty, et al. 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 2012. PNNL-21169. Richland, WA: Pacific Northwest National Laboratory.
• Zachara J.M., M.D. Freshley, G.V. Last, R.E. Peterson, and B.N. Bjornstad. 2012. Updated Conceptual Model for the 300 Area Uranium Groundwater Plume. PNNL-22048. Richland, WA: Pacific Northwest National Laboratory.

2011

• Clarke T.A., M. Edwards, A.J. Gates, A.J. Gates, A. Hall, G. White, and J. Bradley, et al. 2011. "Structure of a Bacterial Cell Surface Decaheme Electron Conduit." Proceedings of the National Academy of Sciences of the United States of America 108, no. 23:9384-9389. PNNL-SA-79964. doi:10.1073/pnas.1017200108
• Felmy A.R., E.S. Ilton, K.M. Rosso, and J.M. Zachara. 2011. "Interfacial Reactivity of Radionuclides: Emerging Paradigms from Molecular Level Observations." Mineralogical Magazine 75, no. 4:2379-2391. PNNL-SA-80615.
• Greskowiak J., M.B. Hay, H. Prommer, C. Liu, V. Post, R. Ma, and J.A. Davis, et al. 2011. "Simulating adsorption of U(VI) under transient groundwater flow and hydrochemistry - Physical versus non-equilibrium model." Water Resources Research 47. PNNL-SA-76544. doi:10.1029/2010WR010118
• Hay M.B., D.L. Stoliker, J.A. Davis, and J.M. Zachara. 2011. "Characterization of the intragranular water regime within subsurface sediments: Pore volume, surface area, and mass transfer limitations." Water Resources Research 47. PNNL-SA-77732. doi:10.1029/2010WR010303
• Liu C., J. Shang, and J.M. Zachara. 2011. "Multispecies diffusion models: A study of uranyl species diffusion." Water Resources Research 47. PNNL-SA-77903. doi:10.1029/2011WR010575
• Ma R., C. Zheng, M.J. Tonkin, and J.M. Zachara. 2011. "Importance of considering intraborehole flow in solute transport modeling under highly dynamic flow conditions." Journal of Contaminant Hydrology 123, no. 1-2:11-19. PNNL-SA-79419. doi:10.1016/j.jconhyd.2010.12.001
• Plymale A.E., J.K. Fredrickson, J.M. Zachara, A. Dohnalkova, S.M. Heald, D.A. Moore, and D.W. Kennedy, et al. 2011. "Competitive Reduction of Pertechnetate (99TcO4-) by Dissimilatory Metal Reducing Bacteria and Biogenic Fe(II)." Environmental Science & Technology 45, no. 3:951-957. PNNL-SA-77182.
• Shang J., C. Liu, Z. Wang, and J.M. Zachara. 2011. "Effect of Grain Size on Uranium(VI) Surface Complexation Kinetics and Adsorption Additivity." Environmental Science & Technology 45, no. 14:6025-6031. PNNL-SA-78613. doi:10.1021/es200920k
• Shi L., S.M. Belchik, A.E. Plymale, S.M. Heald, A. Dohnalkova, K. Sybirna, and H. Bottin, et al. 2011. "Purification and Characterization of [NiFe]-Hydrogenase of Shewanella oneidensis MR-1." Applied and Environmental Microbiology 77, no. 16:5584-5590. PNNL-SA-77194.
• Shi L., S.M. Belchik, Z. Wang, D.W. Kennedy, A. Dohnalkova, M.J. Marshall, and J.M. Zachara, et al. 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, no. 15:5521-5523. PNNL-SA-77918. doi:10.1128/AEM.00614-11
• Stoliker D.L., D.B. Kent, and J.M. Zachara. 2011. "Quantifying differences in the impact of variable chemistry on equilibrium uranium(VI) adsorption properties of aquifer sediments." Environmental Science & Technology 45, no. 20:8733-8740. PNNL-SA-82310. doi:10.1021/es202677v
• Wang Z., J.M. Zachara, J.F. Boily, Y. Xia, C.T. Resch, D.A. 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, no. 10:2965-2979. PNNL-SA-75951.
• Yin J., R. Haggerty, D.L. Stoliker, D.B. Kent, J.D. Istok, J. Greskowiak, and J.M. Zachara. 2011. "Transient groundwater chemistry near a river: Effects on U(VI) transport in laboratory column experiments." Water Resources Research 47. PNNL-SA-79833. doi:10.1029/2010WR009369
• Zachara J.M., B.N. Bjornstad, J.N. Christensen, M.S. Conrad, J.K. Fredrickson, M.D. Freshley, and R. Haggerty, et al. 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 2011. PNNL-20257. Richland, WA: Pacific Northwest National Laboratory.
• Zachara J.M., R.K. Kukkadapu, T. Peretyazhko, M.E. Bowden, C.M. Wang, D.W. Kennedy, and D.A. Moore, et al. 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, no. 21:6330-6349. PNNL-SA-76025. doi:10.1016/j.gca.2011.06.030

2010

• Boily J.F., P.L. Gassman, T. Peretyazhko, J. Szanyi, and J.M. Zachara. 2010. "FTIR Spectral Components of Schwertmannite." Environmental Science & Technology 44, no. 4:1185-1190. PNNL-SA-71223.
• Greskowiak J., H. Prommer, C. Liu, V. Post, R. Ma, C. Zheng, and J.M. 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. PNNL-SA-68626. doi:10.1029/2009WR008781
• Icenhower J.P., N. Qafoku, J.M. Zachara, and W.J. 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, no. 8:721-752. PNNL-SA-74548. doi:10.2475/08.2010.02
• Ilton E.S., J.M. Zachara, D.A. Moore, J.P. McKinley, A.D. Eckberg, C.L. Cahill, and A.R. Felmy. 2010. "Dissolution study of Metatorbernite: Thermodynamic Properties and the effect of pH and Phosphate." Environmental Science & Technology 44, no. 19:7521-7526. PNNL-SA-72694. doi:10.1021/es101619f
• Liu C., L. Zhong, and J.M. Zachara. 2010. "Uranium(VI) Diffusion in Low-Permeability Subsurface Materials." Radiochimica Acta 98, no. 9-11:719-726. PNNL-SA-69260. doi:10.1524/ract.2010.1773
• Ma R., C. Zheng, H. Prommer, J. Greskowiak, C. Liu, J.M. Zachara, and M.L. 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. PNNL-SA-67581. doi:10.1029/2009WR008168
• Murakami H., H. Murakami, X. Chen, M.S. Hahn, Y. Liu, M.L. Rockhold, and V.R. Vermeul, et al. 2010. "Bayesian approach for three-dimensional aquifer characterization at the Hanford 300 Area." Hydrology and Earth System Sciences 14. PNNL-SA-75939. doi:10.5194/hess-14-1989-2010
• Peretyazhko T., J.M. Zachara, D.W. Kennedy, J.K. Fredrickson, B.W. Arey, J.P. McKinley, and C.M. Wang, et al. 2010. "Ferrous Phosphate Surface Precipitates Resulting from the Reduction of Intragrain 6-line Ferrihydrite by Shewanella oneidensis MR-1." Geochimica et Cosmochimica Acta 74, no. 13:3751-3767. PNNL-SA-67257. doi:10.1016/j.gca.2010.04.008
• Peretyazhko T., J.M. Zachara, D.W. Kennedy, J.K. Fredrickson, B.W. Arey, J.P. McKinley, and C.M. Wang, et al. 2010. "Ferrous phosphate surface precipitates resulting from the reduction of intragrain 6-line ferrihydrite by Shewanella oneidensis MR-1." Geochimica et Cosmochimica Acta 74, no. 13:3751-3767. PNNL-SA-72089. doi:10.1016/j.gca.2010.04.008
• Reardon C.L., A. Dohnalkova, P. Nachimuthu, D.W. Kennedy, D. Saffarini, B.W. Arey, and L. Shi, et al. 2010. "Role of Outer-Membrane Cytochromes MtrC and OmcA in the Biomineralization of Ferrihydrite by Shewanella oneidensis MR-1." Geobiology 8, no. 1:56-68. PNNL-SA-57383. doi:10.1111/j.1472-4669.2009.00226.x
• Um W., J.M. Zachara, C. Liu, D.A. Moore, and K.A. Rod. 2010. "Resupply Mechanism to a Contaminated Aquifer: A Laboratory Study of U(VI) Desorption from Capillary Fringe Sediments." Geochimica et Cosmochimica Acta 74, no. 18:5155-5170. PNNL-SA-63210.
• Vermeul V.R., J.P. McKinley, D.R. Newcomer, R.D. Mackley, and J.M. Zachara. 2010. "River-Induced Flow Dynamics in Long-Screen Wells and Impact on Aqueous Samples." Ground Water 49, no. 4:515-524. PNNL-SA-71263. doi:10.1111/j.1745-6584.2010.00769.x
• Zachara J.M., B.N. Bjornstad, J.N. Christensen, M.E. Conrad, J.K. Fredrickson, M.D. Freshley, and R. Haggerty, et al. 2010. Multi-Scale Mass Transfer Processes Controlling Natural Attenuation and Engineered Remediation: An IFRC Focused on Hanford’s 300 Area Uranium Plume. PNNL-19209. Richland, WA: Pacific Northwest National Laboratory.

2009

• Fredrickson J.K., J.M. Zachara, A.E. Plymale, S.M. Heald, J.P. McKinley, D.W. Kennedy, and C. Liu, et al. 2009. "Oxidative Dissolution Potential of Biogenic and Abiogenic TcO2 in Subsurface Sediments." Geochimica et Cosmochimica Acta 73, no. 8:962-976. PNNL-SA-61187. doi:10.1016/j.gca.2009.01.027
• Hartshorne R.S., C.L. Reardon, D.E. Ross, J. Nuester, J. Nuester, T.A. Clarke, and A.J. Gates, et al. 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, no. 52:22169-22174. PNNL-SA-68587. doi:10.1073/pnas.0900086106
• Jaisi D.P., H. Dong, A.E. Plymale, J.K. Fredrickson, J.M. 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, no. 1-4:127-138. PNNL-SA-65652. doi:10.1016/j.chemgeo.2009.02.018
• Liu C., J.M. Zachara, L. Zhong, S.M. Heald, Z. Wang, B. Jeon, and J.K. Fredrickson. 2009. "Microbial Reduction of Intragrain U(VI) in Contaminated Sediment." Environmental Science & Technology 43, no. 13:4928-4933. PNNL-SA-62609. doi:10.1021/es8029208
• Liu C., Z. Shi, and J.M. Zachara. 2009. "Kinetics of Uranium(VI) Desorption from Contaminated Sediments: Effect of Geochemical Conditions and Model Evaluation." Environmental Science & Technology 43, no. 17:6560-6566. PNNL-SA-65042.
• Marshall M.J., A. Dohnalkova, D.W. Kennedy, A.E. Plymale, S.H. Thomas, F.E. Loffler, and R. Sanford, et al. 2009. "Electron donor-dependent radionuclide reduction and nanoparticle formation by Anaeromyxobacter dehalogenans strain 2CP-C." Environmental Microbiology 11, no. 2:534-543. PNNL-SA-57365.
• Peretyazhko T., J.M. Zachara, J.F. Boily, Y. Xia, P.L. Gassman, B.W. Arey, and W.D. Burgos. 2009. "Mineralogical transformations controlling acid mine drainage chemistry." Chemical Geology 262, no. 3-4:169-178. PNNL-SA-62273.
• Pierce E.M., M.D. Freshley, S.S. Hubbard, B.B. Looney, J.M. Zachara, L. Liang, and D. Lesmes, et al. 2009. Scientific Opportunity to Reduce Risk in Groundwater and Soil Remediation. PNNL-18516. Richland, WA: Pacific Northwest National Laboratory.
• Shi L., D. Richardson, Z. Wang, S.N. Kerisit, K.M. Rosso, J.M. Zachara, and J.K. Fredrickson. 2009. "The Roles of Outer Membrane Cytochromes of Shewanella and Geobacter in Extracellular Electron Transfer." Environmental Microbiology Reports 1, no. 4:220-227. PNNL-SA-64248. doi:10.1111/j.1758-2229.2009.00035.x
• Shi Z., C. Liu, J.M. Zachara, Z. Wang, and B. Deng. 2009. "Inhibition Effect of Secondary Phosphate Mineral Precipitation on Uranium Release from Contaminated Sediments." Environmental Science & Technology 43, no. 21:8344-8349. PNNL-SA-65375. doi:10.1021/es9021359
• Singer D.M., J.M. Zachara, and G.E. Brown. 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, no. 3:630-636. PNNL-SA-61175.
• Stubbs J.E., J.E. Stubbs, L.A. Veblen, D. Elbert, J.M. Zachara, J.A. Davis, and D.R. Veblen. 2009. "Newly recognized hosts for uranium in the Hanford Site vadose zone." Geochimica et Cosmochimica Acta 73, no. 6:1563-1576. PNNL-SA-63209.

2008

• Bond D.L., J.A. Davis, and J.M. Zachara. 2008. "Uranium(VI) Release from Contaminated Vadose Zone Sediments: Estimation of Potential Contributions from Dissolution and Desorption." In Adsorption of Metals to Geomedia II, edited by MO Barnett, DB Kent. 375-416. Boston, Massachusetts:Elsevier. PNNL-SA-58541.
• Cantrell K.J., R.J. Serne, J.M. Zachara, K.M. Krupka, P.E. Dresel, C.F. Brown, and M.D. 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, edited by FM Mann. Richland, Washington:U.S. Department of Energy, Office of River Protection. PNNL-SA-31919.
• Clarke T.A., T. Holley, T. Holley, R.S. Hartshorne, J.K. Fredrickson, J.M. Zachara, and L. Shi, et al. 2008. "The role of multihaem cytochromes in the respiration of nitrite in Escherichia coli and Fe(III) in Shewanella oneidensis." Biochemical Society: Transactions 36, no. Pt. 5:1005-1010. PNNL-SA-62839. doi:10.1042/BST0361005
• Fredrickson J.K., and J.M. Zachara. 2008. "Electron Transfer at the Microbe-Mineral Interface: A Grand Challenge in Biogeochemistry." Geobiology 6, no. 3:245-253. PNNL-SA-57273.
• Icenhower J.P., N. Qafoku, W.J. Martin, and J.M. Zachara. 2008. The Geochemistry of Technetium: A Summary of the Behavior of an Artificial Element in the Natural Environment. PNNL-18139. Richland, WA: Pacific Northwest National Laboratory.
• Ilton E.S., N. Qafoku, C. Liu, D.A. Moore, and J.M. Zachara. 2008. "Advective Removal of Intraparticle Uranium from Contaminated Vadose Zone Sediments, Hanford, USA." Environmental Science & Technology 42, no. 5:1565-1571. PNNL-SA-52135. doi:10.1021/es071113m
• Liu C., J.M. Zachara, N. Qafoku, and Z. Wang. 2008. "Scale-dependent desorption of uranium from contaminated subsurface sediments." Water Resources Research 44. PNNL-SA-56814. doi:10.1029/2007WR006478
• Marshall M.J., A.E. Plymale, D.W. Kennedy, L. Shi, Z. Wang, S.B. Reed, and A. Dohnalkova, et al. 2008. "Hydrogenase- and Outer Membrane c-Type Cytochrome-Facilitated Reduction of Technetium(VII) by Shewanella oneidensis MR-1." Environmental Microbiology 10, no. 1:125-136. PNNL-SA-52126. doi:10.1111/j.1462-2920.2007.01438.x
• Peretyazhko T., J.M. Zachara, S.M. Heald, B. Jeon, R.K. Kukkadapu, C. Liu, and D.A. Moore, et al. 2008. "Heterogeneous Reduction of Tc(VII) by Fe(II) at the Solid-Water Interface." Geochimica et Cosmochimica Acta 72, no. 6:1521-1539. PNNL-SA-56929. doi:10.1016/j.gca.2008.01.004
• Peretyazhko T., J.M. Zachara, S.M. Heald, R.K. Kukkadapu, C. Liu, A.E. Plymale, and C.T. Resch. 2008. "Reduction of Tc(VII) by Fe(II) Sorbed on Al (hydr)oxides." Environmental Science & Technology 42, no. 15:5499-5506. PNNL-SA-58538. doi:10.1021/es8003156
• Serne R.J., B.N. Bjornstad, H.T. Schaef, B.A. Williams, D.C. Lanigan, D.G. Horton, and R.E. Clayton, et al. 2008. Characterization of Vadose Zone Sediment: Uncontaminated RCRA Borehole Core Samples and Composite Samples. PNNL-13757-1 Rev. 1. Richland, WA: Pacific Northwest National Laboratory.
• Shi L., S. Deng, M.J. Marshall, Z. Wang, D.W. Kennedy, A. Dohnalkova, and H.M. Mottaz, et al. 2008. "Direct Involvement of Type II Secretion System in Extracellular Translocation of Shewanella Oneidensis Outer Membrane Cytochromes MtrC and OmcA." Journal of Bacteriology 190, no. 15:5512-5516. PNNL-SA-55117. doi:10.1128/JB.00514-08
• Wang Z., C. Liu, X. Wang, M.J. Marshall, J.M. Zachara, K.M. Rosso, and M. Dupuis, et al. 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, no. 21:6746-6755. PNNL-SA-57287. doi:10.1128/AEM.01454-08
• Wang Z., J.M. Zachara, C. Liu, P.L. Gassman, A.R. Felmy, and S.B. Clark. 2008. "A cryogenic fluorescence spectroscopic study of uranyl carbonate, phosphate, and oxyhydroxide minerals." Radiochimica Acta 96, no. 9-11:591-598. PNNL-SA-57377. doi:10.1524/ract.2008.1541
• Wellman D.M., J.M. Zachara, C. Liu, N. Qafoku, S.C. Smith, and S.W. Forrester. 2008. "Advective Desorption of Uranium (VI) from Contaminated Hanford Vadose Zone Sediments under Saturated and Unsaturated Conditions." Vadose Zone Journal 7, no. 4:1144-1159. PNNL-SA-60268. doi:10.2136/vzj2007.0166
• Zachara J.M., M.D. Freshley, and F.M. Mann. 2008. Science Road Map for Phase 2 of the Tank-Farm Vadose Zone Program. PNNL-17684; RPP-PLAN-38191, Rev. 0. Richland, WA: Pacific Northwest National Laboratory.

2007

• Arai Y., M.A. Marcus, N. Tamura, J.A. Davis, and J.M. Zachara. 2007. "Spectroscopic Evidence for Uranium Bearing Precipitates in Vadose Zone Sediments at the Hanford 300-Area Site." Environmental Science & Technology 41, no. 13:4633-4639. PNNL-SA-57346.
• Cantrell K.J., J.M. Zachara, P.E. Dresel, K.M. Krupka, and R.J. Serne. 2007. Geochemical Processes Data Package for the Vadose Zone in the Single-Shell Tank Waste Management Areas at the Hanford Site. PNNL-16663. Richland, WA: Pacific Northwest National Laboratory.
• Gee G.W., M. Oostrom, M.D. Freshley, M.L. Rockhold, and J.M. Zachara. 2007. "Hanford Site Vadose-Zone Studies: An Overview." Vadose Zone Journal 6, no. 4:899-905. PNNL-SA-53286. doi:10.2136/vzj2006.0179
• Hartshorne R.S., B.N. Jepson, T.A. Clarke, S.J. Field, J.K. Fredrickson, J.M. Zachara, and L. Shi, et al. 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, no. 7:1083-1094. PNNL-SA-57073. doi:10.1007/s00775-007-0278-y
• Heald S.M., J.M. Zachara, B. Jeon, J.P. McKinley, R.K. Kukkadapu, and D.A. 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, 882, 173-175. Melville, New York:American Institute of Physics. PNNL-SA-50815. doi:10.1063/1.2644465
• Komlos J., R.K. Kukkadapu, J.M. Zachara, and P.R. 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, no. 13:2996-3004. PNNL-SA-46808. doi:10.1016/j.watres.2007.03.019
• Liu C., B. Jeon, J.M. Zachara, and Z. Wang. 2007. "Influence of Calcium on Microbial Reduction of Solid Phase Uranium (VI)." Biotechnology and Bioengineering 97, no. 6:1415-1422. PNNL-SA-52137. doi:10.1002/bit.21357
• Liu C., J.M. Zachara, N.S. Foster, and J. Strickland. 2007. "Kinetics of Reductive Dissolution of Hematite by Bioreduced Anthraquinone-2,6-disulfate." Environmental Science & Technology41, no. 22:7730-7735. PNNL-SA-54233. doi:10.1021/es070768k
• McKinley J.P., J.M. Zachara, J. Wan, D.E. Mccready, and S.M. 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, no. 4:1004-1017. PNNL-SA-54463. doi:10.2136/vzj2006.0184
• McKinley J.P., J.M. Zachara, S.C. 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, no. 2:305-325. PNNL-SA-52623.
• Shi L., T.C. Squier, J.M. Zachara, and J.K. Fredrickson. 2007. "Respiration of metal (hydr)oxides by Shewanella and Geobacter: a key role for multihaem c-type cytochromes." Molecular Microbiology 65, no. 1:12-20. PNNL-SA-56434. doi:10.1111/j.1365-2958.2007.05783.x
• Zachara J.M., C.F. Brown, J.N. Christensen, J.A. Davis, P.E. Dresel, C. Liu, and S.D. Kelly, et al. 2007. A Site Wide Perspective on Uranium Geochemistry at the Hanford Site. PNNL-17031. Richland, WA: Pacific Northwest National Laboratory.
• Zachara J.M., J.K. Fredrickson, R.K. Kukkadapu, and Y.A. Gorby. 2007. "Anaerobic Microbial-Mineral Processes with Fe(III) Oxides: Experimental Considerations and Approaches." In Methods for Investigating Microbial-Mineral Interactions: CMS Workshop Lectures, edited by Patricia A. Maurice and Leslie A. Warren. 117-165. West Lafayette, Indiana:The Clay Minerals Society. PNNL-SA-46735.
• Zachara J.M., R.J. Serne, M.D. Freshley, F.M. Mann, F.J. Anderson, M.I. Wood, and T.E. Jones, et al. 2007. "Geochemical Processes Controlling Migration of High Level Wastes in Hanford's Vadose Zone." Vadose Zone Journal 6, no. 4:985-1003. PNNL-SA-53273. doi:10.2136/vzj2006.0180
• Zachara J.M., S.M. Heald, B. Jeon, R.K. Kukkadapu, C. Liu, J.P. McKinley, and A. Dohnalkova, et al. 2007. "Reduction of Pertechnetate [Tc(VII)] by Aqueous Fe(II) and the Nature of Solid Phase Redox Products." Geochimica et Cosmochimica Acta 71, no. 9:2137-2157. PNNL-SA-50399. doi:doi:10.1016/j.gca.2006.10.025

2006

• Catalano J.G., J.P. McKinley, J.M. Zachara, S.M. Heald, S.C. Smith, and G.E. Brown. 2006. "Changes in Uranium Speciation through a Depth Sequence of Contaminated Hanford Sediments." Environmental Science & Technology 40, no. 8:2517-2524. PNNL-SA-46734.
• Chang H., G.V. Korshin, Z. Wang, and J.M. Zachara. 2006. "Adsorption of Uranyl on Gibbsite: A Time-Resolved Laser-Induced Fluorescence Spectroscopy Study." Environmental Science & Technology 40, no. 4:1244-1249. PNNL-SA-48830.
• Fox P.M., J.A. Davis, and J.M. Zachara. 2006. "The Effect of Calcium on Aqueous Uranium (VI) Speciation and Adsorption to Ferrihydrite and Quartz." Geochimica et Cosmochimica Acta70, no. 6:1379-1387. PNNL-SA-48006.
• Fox P.M., J.A. Davis, and J.M. Zachara. 2006. "The effect of calcium on aqueous uranium(VI) speciation and adsorption to ferrihydrite and quartz." Geochimica et Cosmochimica Acta 70, no. 6:1379-1387. PNNL-SA-44029.
• Ilton E.S., C. Liu, W. Yantasee, Z. Wang, D.A. Moore, A.R. Felmy, and J.M. Zachara. 2006. "The Dissolution of Synthetic Na-Boltwoodite in Sodium Carbonate Solutions." Geochimica et Cosmochimica Acta 70, no. 19:4836-4849. PNNL-SA-46902. doi:10.1016/j.gca.2006.06.1553
• Kukkadapu R.K., J.M. Zachara, J.K. Fredrickson, J.P. McKinley, D.W. Kennedy, S.C. 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 Acta70, no. 14:3662-3676. PNNL-SA-39557. doi:10.1016/j.gca.2006.05.004
• Liu C., B. Jeon, J.M. Zachara, Z. Wang, A. Dohnalkova, and J.K. Fredrickson. 2006. "Kinetics of Microbial Reduction of Solid Phase U(VI)." Environmental Science & Technology 40, no. 20:6290-6296. PNNL-SA-48993.
• Liu C., J.M. Zachara, W. Yantasee, P.D. Majors, and J.P. McKinley. 2006. "Microscopic Reactive Diffusion of Uranium in the Contaminated Sediments at Hanford, United States." Water Resources Research 42, no. W12420:1-15. PNNL-SA-47152. doi:10.1029/2006WR005031
• Marshall M.J., A.S. Beliaev, A. Dohnalkova, D.W. Kennedy, L. Shi, Z. Wang, and M.I. Boyanov, et al. 2006. "c-Type Cytochrome-Dependent Formation of U(IV) Nanoparticles by Shewanella oneidensis." PLoS Biology 4, no. 8:1324-1333. PNNL-SA-47126.
• McKinley J.P., J.M. Zachara, C. Liu, S.M. Heald, B.I. 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, no. 8:1873-1887. PNNL-SA-43416. doi:10.1016/j.gca.2005.10.037
• Shi L., B. Chen, Z. Wang, D.A. Elias, M.U. Mayer, Y.A. Gorby, and S. Ni, et al. 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, no. 13:4705-4714. PNNL-SA-45401. doi:10.1128/JB.01966-05
• Xiong Y., L. Shi, B. Chen, M.U. Mayer, B.H. Lower, y. londer, and S. Bose, et al. 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 Society128, no. 43:13978-13979. PNNL-SA-50097. doi:10.1021/ja063526d

2005

• Ainsworth C.C., J.M. Zachara, K.B. Wagnon, S.G. McKinley, C. Liu, S.C. Smith, and H.T. Schaef, et al. 2005. "Impact of Highly Basic Solutions on Sorption of Cs+ to Subsurface Sediments from the Hanford Site, USA." Geochimica et Cosmochimica Acta 69, no. 20:4787-4800. PNNL-SA-39954.
• Dichristina T.J., J.K. Fredrickson, and J.M. Zachara. 2005. "Enzymology of Electron Transport: Energy Generation with Geochemical Consequences." In Molecular Geomicrobiology, Reviews in Mineralogy & Geochemistry, edited by J.F. Banfield, J. Cervini-Silva and K.H. Nealson. 27-52. Chantilly, Virginia:Mineralogical Society of America. PNNL-SA-47870.
• Dong W., W.P. Ball, C. Liu, Z. Wang, A.T. Stone, J. Bai, and J.M. Zachara. 2005. "Influence of Calcite and Dissolved Calcium on Uranium(VI) Sorption to a Hanford Subsurface Sediment." Environmental Science & Technology 39, no. 20:7949-7955. PNNL-SA-46988. doi:10.1021/es0505088
• Kelly S.D., K.M. Kemner, S.C. Brooks, J.K. Fredrickson, S.L. Carroll, D.W. Kennedy, and J.M. Zachara, et al. 2005. "Ca-UO2-CO3 Complexation - Implications for Bioremediation of U(VI)." Physica Scripta T115. PNNL-SA-65625. doi:10.1238/Physica.Topical.115a00915
• Kukkadapu R.K., J.M. Zachara, J.K. Fredrickson, D.W. Kennedy, A. Dohnalkova, and D.E. McCready. 2005. "Ferrous Hydroxy Carbonate is a Stable Transformation Product of Biogenic Magnetite." The American Mineralogist 90, no. 2-3:510-515. PNNL-SA-41786.
• Liu C., J.M. Zachara, L. Zhong, R.K. Kukkadapu, J.E. Szecsody, and D.W. Kennedy. 2005. "Influence of Sediment Bioreduction and Reoxidation on Uranium Sorption." Environmental Science & Technology 39, no. 11:4125-4133. PNNL-SA-42725.
• Peterson R.E., E.J. Freeman, P.D. Thorne, M.D. Williams, J.W. Lindberg, C.J. Murray, and M.J. Truex, et al. 2005. Contaminants of Potential Concern in the 300-FF-5 Operable Unit: Expanded Annual Groundwater Report for Fiscal Year 2004. PNNL-15127. Richland, WA: Pacific Northwest National Laboratory.
• Qafoku N., J.M. Zachara, C. Liu, P.L. Gassman, O. Qafoku, and S.C. Smith. 2005. "Kinetic Desorption and Sorption of U(VI) During Reactive Transport in a Contaminated Hanford Sediment." Environmental Science & Technology 39, no. 9:3157-3165. PNNL-SA-42960. doi:10.1021/es048462q
• Wang Z., J.M. Zachara, J.P. McKinley, and S.C. 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 & Technology 39. PNNL-SA-42959.
• Wang Z., J.M. Zachara, P.L. Gassman, C. Liu, O. Qafoku, W. Yantasee, and J.G. Catalano. 2005. "Fluorescence Spectroscopy of U(VI)-Silicates and U(VI)-Contaminated Hanford Sediment." Geochimica et Cosmochimica Acta 69, no. 6:1391-1403. PNNL-SA-42812. doi:10.1016/j.gca.2004.08.028
• Zachara J.M., J.A. Davis, C. Liu, J.P. McKinley, N. Qafoku, D.M. Wellman, and S.B. Yabusaki. 2005. Uranium Geochemistry in Vadose Zone and Aquifer Sediments from the 300 Area Uranium Plume. PNNL-15121. Richland, WA: Pacific Northwest National Laboratory.
• Zhong L., C. Liu, J.M. Zachara, D.W. Kennedy, J.E. Szecsody, and B.D. Wood. 2005. "Oxidative Remobilization of Biogenic Uranium (IV) Precipitates: Effects of Iron (II) and pH." Journal of Environmental Quality 34, no. 5:1763-1771. PNNL-SA-42839.

2004

• Catalano J.G., S.M. Heald, J.M. Zachara, and G.E. Brown Jr. 2004. "Spectroscopic and Diffraction Study of Uranium Speciation in Contaminated Vadose Zone Sediments from the Hanford Site, Washington State." Environmental Science & Technology 38, no. 10:2822-2828. PNNL-SA-42813.
• Fredrickson J.K., J.M. Zachara, D.L. Balkwill, D.W. Kennedy, S.W. Li, H.M. Kostandarithes, and M.J. Daly, et al. 2004. "Geomicrobiology of High Level Nuclear Waste-Contaminated Vadose Sediments at the Hanford Site, Washington State." Applied and Environmental Microbiology 70, no. 7:4230-4241. PNNL-SA-42098.
• Fredrickson J.K., J.M. Zachara, D.W. Kennedy, R.K. Kukkadapu, J.P. McKinley, S.M. Heald, and C. Liu, et al. 2004. "Reduction of TcO4- by sediment-associated biogenic Fe(II)." Geochimica et Cosmochimica Acta 68, no. 15:3171-3187. PNNL-SA-42096.
• Kukkadapu R.K., J.M. Zachara, J.K. Fredrickson, and D.W. 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, no. 13:2799-2814. PNNL-SA-37482.
• Liu C., J.M. Zachara, A.R. Felmy, and Y.A. Gorby. 2004. "An Electrodynamics-Based Model for Ion Diffusion in Microbial Polysaccharides." Colloids and Surfaces. B, Biointerfaces 38. PNNL-SA-41435.
• Liu C., J.M. Zachara, and S.C. 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, no. 3-4:217-238. PNNL-SA-35615.
• Liu C., J.M. Zachara, O. Qafoku, J.P. McKinley, S.M. Heald, and Z. Wang. 2004. "Dissolution of Uranyl Microprecipitates from Subsurface Sediments at Hanford Site, USA." Geochimica et Cosmochimica Acta 68, no. 22:4519-4537. PNNL-SA-41756.
• McKinley J.P., J.M. Zachara, S.M. Heald, A. Dohnalkova, M. Newville, and S.R. Sutton. 2004. "Microscale Distribution of Cesium Sorbed to Biotite and Muscovite." Environmental Science & Technology 38, no. 4:1017-1023. PNNL-SA-39021.
• Wang Z., J.M. Zachara, W. Yantasee, P.L. Gassman, C. Liu, and A.G. Joly. 2004. "Cryogenic Laser Induced Fluorescence Characterization of U(VI) in Hanford Vadose Zone Pore Waters." Environmental Science & Technology 38. PNNL-SA-41205.
• Zachara J.M., C.C. Ainsworth, G.E. Brown, J.G. Catalano, J.P. McKinley, O. Qafoku, and S.C. Smith, et al. 2004. "Chromium Speciation and Mobility in a High Level Nuclear Waste Vadose Zone Plume." Geochimica et Cosmochimica Acta 68, no. 1:13-30. PNNL-SA-36806.
• Zachara J.M., R.K. Kukkadapu, P.L. Gassman, A. Dohnalkova, J.K. Fredrickson, and T. Anderson. 2004. "Biogeochemical Transformation of Fe Minerals in a Petroleum-Contaminated Aquifer." Geochimica et Cosmochimica Acta 68, no. 8:1791-1805. PNNL-SA-39996.

2003

• Brooks S.C., J.K. Fredrickson, S.L. Carroll, D.W. Kennedy, J.M. Zachara, A.E. Plymale, and S.D. Kelly, et al. 2003. "Inhibition of bacterial U(VI) reduction by calcium." Environmental Science & Technology 37, no. 9:1850-1858. PNNL-SA-39586.
• Dong H., R.K. Kukkadapu, J.K. Fredrickson, J.M. Zachara, D.W. Kennedy, and H.M. Kostandarithes. 2003. "Microbial Reduction of Structural Fe(III) in Illite and Goethite." Environmental Science & Technology Vol. 37, no. 7:1268-1276. PNNL-SA-37299.
• Fredrickson J.K., S. Kota, R.K. Kukkadapu, C. Liu, and J.M. Zachara. 2003. "Influence of Electron Donor/Acceptor Concentrations on Hydrous Ferric Oxide (HFO) Bioreduction." Biodegradation 14, no. 2:91-103. PNNL-SA-38621.
• Kukkadapu R.K., J.M. Zachara, J.K. Fredrickson, S.C. Smith, A. Dohnalkova, and C.K. Russell. 2003. "Transformation of 2-line Ferrihydrite to 6-line Ferrihydrite under Oxic and Anoxic Conditions." The American Mineralogist 88, no. 11-12:1903-1914 pt. 2. PNNL-SA-37214.
• Liu C., J.M. Zachara, O. Qafoku, and S.C. Smith. 2003. "Effect of Temperature on Cs+ Sorption and Desorption in Subsurface Sediments at Hanford Site, U.S.A." Environmental Science & Technology 37, no. 12:2640-2645. PNNL-SA-37351.
• Liu C., J.M. Zachara, S.C. Smith, J.P. McKinley, and C.C. Ainsworth. 2003. "Desorption Kinetics of Radiocesium from Subsurface Sediments at Hanford Site, USA." Geochimica et Cosmochimica Acta 67, no. 16:2893-2912. PNNL-SA-37245.
• Mayes M.A., P.M. Jardine, T.L. Mehlhorn, B.N. Bjornstad, J.L. Ladd, and J.M. Zachara. 2003. "Transport of Multiple Tracers in Variably Saturated Humid Region Structured Soils and Semi-arid Region Laminated Sediments." Journal of Hydrology 275, no. 3-4:141-161. PNNL-SA-37638.
• Pace M.N., M.A. Mayes, P.M. Jardine, P.M. Jardine, T.L. Mehlhorn, J.M. Zachara, and B.N. Bjornstad. 2003. "Quantifying the effects of small-scale heterogeneities on flow and transport in undisturbed cores from the Hanford formation." Vadose Zone Journal 2, no. 4:664-676. PNWD-SA-6737.
• Rosso K.M., J.M. Zachara, J.K. Fredrickson, Y.A. Gorby, and S.C. Smith. 2003. "Nonlocal Bacterial Electron Transfer to Hematite Surfaces." Geochimica et Cosmochimica Acta 67, no. 5:1081-1087. PNNL-SA-35064.

2002

• Bredt P.R., C.C. Ainsworth, F.J. Brockman, D.M. Camaioni, O.B. Egorov, A.R. Felmy, and Y.A. Gorby, et al. 2002. Science to Support DOE Site Cleanup: The Pacific Northwest National Laboratory Environmental Management Science Program Awards -- Fiscal Year 2002 Mid-Year Progress Report. PNNL-13928. Richland, WA: Pacific Northwest National Laboratory.
• Fredrickson J.K., J.M. Zachara, D.W. Kennedy, C. Liu, M.C. Duff, M.C. Duff, and D. Hunter, et al. 2002. "Influence of Mn oxides on the reduction of U(VI) by the metal-reducing bacterium Shewanella putrefaciens." Geochimica et Cosmochimica Acta 66, no. 18:3247-3262. PNNL-SA-35350.
• Freshley M.D., A.L. Bunn, G.W. Gee, T.J. Gilmore, C.T. Kincaid, R.E. Peterson, and A.L. Ward, et al. 2002. Groundwater Protection Program Science and Technology Summary Description. PNNL-14092. Richland, WA: Pacific Northwest National Laboratory.
• Freshley M.D., J.M. Zachara, and M.J. 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, 8 pages. Tucson, Arizona:Arizona Board of Regents. PNNL-SA-37546.
• Liu C., J.M. Zachara, J.K. Fredrickson, D.W. Kennedy, and A. Dohnalkova. 2002. "Modeling the Inhibition of the Bacterial Reduction of U(VI) by beta-MnO2(S)(g)." Environmental Science & Technology 36, no. 7:1452-1459. PNNL-SA-35063.
• Liu C., Y.A. Gorby, J.M. Zachara, J.K. Fredrickson, and C.F. 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 Bioengineering 80, no. 6:637-649. PNNL-SA-35327.
• Serne R.J., B.N. Bjornstad, H.T. Schaef, B.A. Williams, D.C. Lanigan, D.G. Horton, and R.E. Clayton, et al. 2002. Characterization of Vadose Zone Sediment: Uncontaminated RCRA Borehole Core Samples and Composite Samples. PNNL-13757-1. Richland, WA: Pacific Northwest National Laboratory.
• Zachara J.M., R.K. Kukkadapu, J.K. Fredrickson, Y.A. Gorby, and S.C. Smith. 2002. "Biomineralization of Poorly Crystalline Fe(III) Oxides by Dissimilatory Metal Reducing Bacteria (DMRB)." Geomicrobiology Journal 19. PNNL-SA-34050.
• Zachara J.M., S.C. Smith, C. Liu, J.P. McKinley, R.J. Serne, and P.L. Gassman. 2002. "Sorption of Cs+ to Micaceous Subsurface Sediments from the Hanford Site, USA." Geochimica et Cosmochimica Acta 66, no. 2:193-211. PNNL-SA-33718.

2001

• Bredt P.R., F.J. Brockman, D.M. Camaioni, A.R. Felmy, J.W. Grate, B.P. Hay, and N.J. Hess, et al. 2001. Science To Support DOE Site Cleanup: The Pacific Northwest National Laboratory Environmental Management Science Program Awards. PNNL-13564. Richland, WA: Pacific Northwest National Laboratory.
• Fredrickson J.K., J.M. Zachara, R.K. Kukkadapu, Y.A. Gorby, S.C. Smith, and C.F. Brown. 2001. "Biotransformation of Ni-Substituted Hydrous Ferric Oxide by an Fe(III)-Reducing Bacterium." Environmental Science & Technology 35, no. 4:703-712. PNNL-SA-33559.
• Kukkadapu R.K., J.M. Zachara, S.C. Smith, J.K. Fredrickson, and C. Liu. 2001. "Dissimilatory Bacterial Reduction of Al-Substituted Goethite in Subsurface Sediments." Geochimica et Cosmochimica Acta 65, no. 17:2913-2924. PNNL-SA-33140.
• Liu C., and J.M. Zachara. 2001. "Uncertainties of Monod Kinetic Parameters Nonlinearly Estimated from Batch Experiments." Environmental Science & Technology 35, no. 1:133-141. PNNL-SA-33719.
• Liu C., J.M. Zachara, Y.A. Gorby, J.E. Szecsody, and C.F. Brown. 2001. "Microbial Reduction of Fe(III) and Sorption/Precipitation of Fe(II) on Shewanella putrefaciens Strain CN32." Environmental Science & Technology 35, no. 7:1385-1393. PNNL-SA-32595.
• Liu C., S. Kota, J.M. Zachara, J.K. Fredrickson, and C.K. Brinkman. 2001. "Kinetic Analysis of the Bacterial Reduction of Goethite." Environmental Science & Technology 35. PNNL-SA-33918.
• McKinley J.P., C.j. Zeissler, J.M. Zachara, R.J. Serne, R.M. Lindstrom, H.T. Schaef, and R.D. Orr. 2001. "Distribution and Retention of 137Cs in Sediments at the Hanford Site, Washington." Environmental Science & Technology 35, no. 17:3433-3441. PNNL-SA-33709.
• Yeh G.T., W.D. Burgos, and J.M. Zachara. 2001. "Modeling and Measuring Biogeochemical Reactions: System Consistency, Data Needs, and Rate Formulations." Advances in Environmental Research 5. PNNL-SA-35382.
• Zachara J.M., J.K. Fredrickson, S.C. Smith, and P.L. Gassman. 2001. "Solubilization of Fe(III) Oxide-Bound Trace Metals by a Dissimilatory Fe(III) Reducing Bacterium." Geochimica et Cosmochimica Acta 65, no. 1:75-93. PNNL-SA-31367.
• Zachara J.M., N.S. Foster, J.E. Amonette, E.J. Bylaska, A.R. Felmy, P.L. Gassman, and S.M. Heald, et al. 2001. Annual Report 2000 Environmental Dynamics and Simulation. PNNL-13456. Richland, WA: Pacific Northwest National Laboratory.

2000

• Dong H., J.K. Fredrickson, D.W. Kennedy, J.M. Zachara, R.K. Kukkadapu, and T.C. Onstott. 2000. "Mineral Transformations Associated with the Microbial Reduction of Magnetite." Chemical Geology 169. PNNL-SA-32933.
• Fredrickson J.K., J.M. Zachara, D.W. Kennedy, Y.A. Gorby, S.W. Li, and K.M. Krupka. 2000. "Reduction of U(VI) in Goethite (a-FeOOH) Suspensions by a Dissimilatory Metal-Reducing Bacterium." Geochimica et Cosmochimica Acta 64. PNNL-SA-31369.
• Liu C., J.E. Szecsody, J.M. Zachara, and W.P. Ball. 2000. "Use of the Generalized Integral Transform Method for Solving Equations of Solute Transport in Porous Media." Advances in Water Resources 23, no. 5:483-492. PNNL-SA-32529.
• Zachara J.M., N.S. Foster, J.E. Amonette, E.J. Bylaska, A.R. Felmy, P.L. Gassman, and S.M. Heald, et al. 2000. Annual Report 1999 Environmental Dynamics & Simulation. PNNL-13206. Richland, WA: Pacific Northwest National Laboratory.
• Zachara J.M., S.C. Smith, and J.K. 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, no. 8:1345-1362. PNNL-SA-31368.

1998

• Szecsody J.E., A. Chilakapati, J.M. Zachara, and A.L. Garvin. 1998. "Influence of Iron Oxide Inclusion Shape on Co(II/III)EDTA Reactive Transport Through Spatially Heterogeneous Sediment." Water Resources Research 34, no. 10:2501-2514. PNNL-SA-30264.
• Zachara J.M., J.K. Fredrickson, S.W. Li, D.W. Kennedy, S.C. Smith, and P.L. Gassman. 1998. "Bacterial Reduction of Crystalline Fe3+ Oxides in Single Phase Suspensions and Subsurface Materials." The American Mineralogist 83, no. 11-12:1426-1443. PNNL-SA-30256.