Skip to Main Content U.S. Department of Energy
Energy and Environment Directorate

Nik Qafoku

Nik Qafoku

Pacific Northwest National Laboratory
PO Box 999
Richland, WA 99352
(509) 371-6089

Biography

Nik Qafoku is a chief scientist and laboratory fellow in the Environmental Subsurface Science Group of EED. He received the B.S. degree and the Doctor of Science degree in soil fertility and soil chemistry from the College of Agronomy and Environmental Sciences of the Agricultural University of Tirana, Albania. He served as assistant professor, professor, department head and vice-dean for research of this College. He was then nominated director of the science, research and training directorate of the Department of Agriculture and Food and supervised the research conducted in the research institutes and stations in Albania.

In 1994 he was awarded a Senior Fulbright Scholarship and conducted soil systems modeling work at Virginia Polytechnic Institute and State University. Later that year, he was accepted in the graduate school of the University of Georgia where he studied environmental soil science, applied math and computer science. He graduated in 1998 finishing a double-degree program (M.S. in Applied Mathematics and Computer Sciences and Ph.D. in Environmental Soil Chemistry and Physics). He served as a teaching assistant and received the outstanding graduate teaching award from the University of Georgia. He worked as a postdoctoral research associate from 1999-2000 at the University of Georgia, and joined the PNNL in June of 2000 initially as a postdoctoral researcher. Since then, Nik has been promoted three time to the categories of research scientist, senior research scientist level III and IV, chief scientist level V, and Laboratory Fellow.

Research Interests

  • Transport-controlled mobilization and immobilization of contaminants in heterogeneous environments
  • Elemental cycling in soils and sediments
  • Changes in aquifer geochemistry and contaminant behavior in aquifers exposed to leaking CO2 gas from deep subsurface storage
  • Waste form performance and interactions in different environments

Education and Credentials

  • Ph.D. December 1998, Environmental Soil Chemistry, University of Georgia, Athens, GA
  • M.S. December 1998, Computer Science&Applied Mathematics, University of Georgia, Athens, GA
  • Doctor of Science June 1990, Soil Science, Agricultural University of Tirana, Albania
  • B.S. June 1984, Agronomy, Agricultural University of Tirana, Albania

Affiliations and Professional Service

  • American Chemical Society (since 2001; membership number: 2305157)
  • International Union of Soil Science (since 1994; membership number: 312-37130)
  • Soil Science Society of America (since 1994; membership number: 86341)
  • Geochemical Society of America (since 2001)  
  • American Geophysical Union (since 2002; membership number: 30086002)
  • The Clay Minerals Society (2004-2007; membership number: 300279)

Awards and Recognitions

  • Senior Fulbright Scholar (1994)
  • Outstanding Teaching Assistant Award, University of Georgia (1998)
  • Outstanding Performance Awards, PNNL (2005, 2007, 2009, and 2020)
  • Citation of excellence award for associate editor of the Soil Science Society of America Journal (2009)
  • Exceptional Contribution Award, PNNL (2014)
  • EED Paper of Year Award, PNNL (2015)
  • Exceptional Contribution Award, PNNL (2016)
  • EED Paper of Year Award, PNNL (2016)
  • R&D 100 Award (2017)
  • Elected Chair of the Soil Chemistry Division, Soil Science Society of America (2017)
  • Jackson Soil Chemistry and Mineralogy Award, Soil Science Society of America (2019)
  • EED Paper of Year Award, PNNL (2019)
  • Appointed Laboratory Fellow, PNNL (2020)
  • Appointed General Chair, 57th International Annual Meeting, The Clays Minerals Society (2020)
  • Elected Fellow, Soil Science Society of America (2020)
  • Citation of Special Recognition, The Clay Minerals Society (2020)
  • Exceptional Contribution Award, PNNL (2020)

PNNL Publications

2024

  • He X., M.L. Rockhold, Y. Fang, A.R. Lawter, V. Freedman, R.D. Mackley, and N. Qafoku. 2024. "Experimental and Numerical Study of Radioiodine Sorption and Transport in Hanford Sediments." ACS Earth and Space Chemistry 8, no. 2:323-334. PNNL-SA-191180. doi:10.1021/acsearthspacechem.3c00291
  • Robinson J.L., K. Peshtani, J.M. Torgeson, N. Qafoku, O. Qafoku, and L.D. Slater. 2024. Investigating Soil Organic Matter Complexation using Spectral Induced Polarization. PNNL-36760. Richland, WA: Pacific Northwest National Laboratory. Investigating Soil Organic Matter Complexation using Spectral Induced Polarization

2023

  • Placencia-Gomez E., J.L. Robinson, L. Slater, and N. Qafoku. 2023. "Spectral induced polarization monitoring of induced calcite precipitation in subsurface sediments." Geophysical Journal International 232, no. 1:57-69. PNNL-SA-172465. doi:10.1093/gji/ggac318

2022

  • Kukkadapu R.K., Q. Zhao, and N. Qafoku. 2022. "Stability of mineral-organic matter associations under varying biogeochemical conditions." Soil Science Society of America Journal 86, no. 2:159-161. PNNL-SA-170061. doi:10.1002/saj2.20392
  • Leichty S.I., Q. Zhao, C.P. Kasanke, N. Qafoku, K.K. Weitz, and K.S. Hofmockel. 2022. Interrogating organo-mineral interactions by Py-GC/MS and ToF-SIMS. PNNL-33357. Richland, WA: Pacific Northwest National Laboratory. Interrogating organo-mineral interactions by Py-GC/MS and ToF-SIMS
  • Lybrand R.A., O. Qafoku, M.E. Bowden, M.F. Hochella, L. Kovarik, D.E. Perea, and N. Qafoku, et al. 2022. "Fungal hyphae develop where titanomagnetite inclusions reach the surface of basalt grains." Scientific Reports 12. PNNL-SA-163525. doi:10.1038/s41598-021-04157-z
  • Monterroso C., M. Balseiro-Romero, C. Garbisu, P.S. Kidd, N. Qafoku, and P. Baveye. 2022. "Editorial: Searching for Solutions to Soil Pollution: Underlying Soil-Contaminant Interactions and Development of Innovative Land Remediation and Reclamation Techniques." Frontiers in Environmental Science 9. PNNL-SA-168840. doi:10.3389/fenvs.2021.830337
  • Qafoku N., A.R. Lawter, E.C. Gillispie, E.M. McElroy, F.N. Smith, R. Sahajpal, and K.J. Cantrell, et al. 2022. "Calcium carbonate minerals as scavengers of metals and radionuclides: Their role in natural attenuation and remediation." In Advances in Agronomy, edited by D.L. Sparks. 115-152. Cambridge, Massachusetts:Academic Press. PNNL-SA-156685. doi:10.1016/bs.agron.2022.07.003

2021

  • Katsenovich Y., R. Gort, R. Gudavalli, J.E. Szecsody, V.L. Freedman, and N. Qafoku. 2021. "Silicon concentration and pH controls over competitive or simultaneous incorporation of iodate and chromate into calcium carbonate phases." Applied Geochemistry 128. PNNL-SA-153342. doi:10.1016/j.apgeochem.2021.104941
  • Lawter A.R., T.G. Levitskaia, O. Qafoku, M.E. Bowden, F. Cintron Colon, and N. Qafoku. 2021. "Simultaneous immobilization of aqueous co-contaminants using a bismuth layered material." Journal of Environmental Radioactivity 237. PNNL-SA-147691. doi:10.1016/j.jenvrad.2021.106711

2020

  • Bagwell C.E., E.C. Gillispie, A.R. Lawter, and N. Qafoku. 2020. "Evaluation of Gaseous Substrates for Microbial Immobilization of Contaminant Mixtures in Unsaturated Subsurface Sediments." Journal of Environmental Radioactivity 214-215. PNNL-SA-147782. doi:10.1016/j.jenvrad.2020.106183
  • Di Pietro S., H.P. Emerson, Y. Katsenovich, N. Qafoku, and J.E. Szecsody. 2020. "Phyllosilicate mineral dissolution upon alkaline treatment under aerobic and anaerobic conditions." Applied Clay Science 189. PNNL-SA-149956. doi:10.1016/j.clay.2020.105520
  • Moore R.C., C.I. Pearce, J.W. Morad, S. Chatterjee, T.G. Levitskaia, R.M. Asmussen, and A.R. Lawter, et al. 2020. "Iodine Immobilization by Materials through Sorption and Redox-Driven Processes: A Literature Review." Science of the Total Environment 716. PNNL-SA-138461. doi:10.1016/j.scitotenv.2019.06.166
  • Pearce C.I., R.C. Moore, J.W. Morad, R.M. Asmussen, S. Chatterjee, A.R. Lawter, and T.G. Levitskaia, et al. 2020. "Technetium Immobilization by Materials through Sorption and Redox-Driven Processes: A Literature Review." Science of the Total Environment 716. PNNL-SA-138464. doi:10.1016/j.scitotenv.2019.06.195
  • Wang G., J.E. Szecsody, N.M. Avalos, N. Qafoku, and V.L. Freedman. 2020. "In situ precipitation of hydrous ferric oxide (HFO) for remediation of subsurface iodine contamination." Journal of Contaminant Hydrology 235. PNNL-SA-147880. doi:10.1016/j.jconhyd.2020.103705
  • Zhao Q., S.J. Callister, A.M. Thompson, R.K. Kukkadapu, M. Tfaily, L.M. Bramer, and N. Qafoku, et al. 2020. "Strong mineralogic control of soil organic matter composition in response to nutrient addition across diverse grassland sites." Science of the Total Environment 736. PNNL-SA-144529. doi:10.1016/j.scitotenv.2020.137839

2019

  • Asmussen R.M., J. Matyas, N. Qafoku, and A.A. Kruger. 2019. "Silver-Functionalized Silica Aerogels and Their Application in the Removal of Iodine from Aqueous Environments." Journal of Hazardous Materials 379. PNNL-SA-129580. doi:10.1016/j.jhazmat.2018.04.081
  • Bagwell C.E., L. Zhong, J.R. Wells, A.V. Mitroshkov, and N. Qafoku. 2019. "Microbial methylation of iodide in unconfined aquifer sediments at the Hanford Site, USA." Frontiers in Microbiology 10. PNNL-SA-143910. doi:10.3389/fmicb.2019.02460
  • Gillispie E.C., S.E. Taylor, N. Qafoku, and M.F. Hochella. 2019. "Impact of nano iron and manganese metal-oxides on contaminant interaction and micronutrient uptake in agricultural systems - a review." Environmental Chemistry 16, no. 6:377-390. PNNL-SA-141253. doi:10.1071/EN19063
  • Hochella M.F., D. Mogk, J. Ranville, I. Allen, G. Luther, L. Marr, and B.P. McGrail, et al. 2019. "Natural, incidental, and engineered nanomaterials and their impacts on the Earth system." Science 363, no. 6434:Article number eaau8299. PNNL-SA-138605. doi:10.1126/science.aau8299
  • Neeway J.J., D.I. Kaplan, C.E. Bagwell, M.L. Rockhold, J.E. Szecsody, M.J. Truex, and N. Qafoku. 2019. "A review of the behavior of radioiodine in the subsurface at two DOE sites." Science of the Total Environment 691. PNNL-SA-138439. doi:10.1016/j.scitotenv.2019.07.146
  • Ohno T., N.J. Hess, and N. Qafoku. 2019. "Current understanding of the use of alkaline extractions of soils to Investigate soil organic matter and environmental processes." Journal of Environmental Quality 48, no. 6:1561-1564. PNNL-SA-146805. doi:10.2134/jeq2019.08.0292
  • Saslow S.A., S.N. Kerisit, T. Varga, K.C. Johnson, N.M. Avalos, A.R. Lawter, and N. Qafoku. 2019. "Chromate Effect on Iodate Incorporation into Calcite." ACS Earth and Space Chemistry 3, no. 8:1624-1630. PNNL-SA-141592. doi:10.1021/acsearthspacechem.9b00047
  • Szecsody J.E., M.J. Truex, N. Qafoku, J.P. McKinley, K.A. Ivarson, and S. Di Pietro. 2019. "Persistence of Chromate in Vadose Zone and Aquifer Sediments in Hanford, Washington." Science of the Total Environment 676. PNNL-SA-141530. doi:10.1016/j.scitotenv.2019.04.173
  • Utami S.R., F. Mees, M. Dumon, N. Qafoku, and E. Van Ranst. 2019. "Charge fingerprint in relation to mineralogical composition of Quaternary volcanic ash along a climatic gradient on Java Island, Indonesia." CATENA 172. PNNL-SA-135121. doi:10.1016/j.catena.2018.09.024
  • Wang G., N. Qafoku, J.E. Szecsody, C.E. Strickland, C.F. Brown, and V.L. Freedman. 2019. "Time-dependent iodate and iodide adsorption to Fe oxides." ACS Earth and Space Chemistry 3, no. 11:2415-2420. PNNL-SA-142955. doi:10.1021/acsearthspacechem.9b00145

2018

  • Gartman B.N., J.E. Szecsody, C.E. Bagwell, E.S. Arnold, C.F. Brown, S.A. Saslow, and C.I. Pearce, et al. 2018. "Combining reductive and sequestering technologies as a potential remediation strategy for a perched water zone at Hanford, WA." Science of the Total Environment. PNNL-SA-147885.
  • Kerisit S.N., F.N. Smith, M.E. Hoover, S.A. Saslow, and N. Qafoku. 2018. "Incorporation Modes of Iodate in Calcite." Environmental Science & Technology 52, no. 10:5902-5910. PNNL-SA-129924. doi:10.1021/acs.est.8b00339
  • Lawter A.R., N. Qafoku, R.M. Asmussen, R.K. Kukkadapu, O. Qafoku, D.H. Bacon, and C.F. Brown. 2018. "Element mobilization and immobilization from carbonate rocks between CO2 storage reservoirs and the overlying aquifers during a potential CO2 leakage." Chemosphere 197. PNNL-SA-125304. doi:10.1016/j.chemosphere.2017.12.199
  • Lawter A.R., W.L. Garcia, R.K. Kukkadapu, O. Qafoku, M.E. Bowden, S.A. Saslow, and N. Qafoku. 2018. "Technetium and iodine aqueous species immobilization and transformations in the presence of strong reductants and calcite-forming solutions: Remedial action implications." Science of the Total Environment 636. PNNL-SA-129751. doi:10.1016/j.scitotenv.2018.04.240
  • Pearce C.I., J.P. Icenhower, R.M. Asmussen, P.G. Tratnyek, K.M. Rosso, W.W. Lukens, and N. Qafoku. 2018. "Technetium stabilization in low solubility sulfide phases: A review." ACS Earth and Space Chemistry 2, no. 6:532-547. PNNL-SA-132805. doi:10.1021/acsearthspacechem.8b00015
  • Pearce C.I., R.J. Serne, S.A. Saslow, W. Um, R.M. Asmussen, M.D. Miller, and O. Qafoku, et al. 2018. "Characterizing Technetium in Subsurface Sediments for Contaminant Remediation." ACS Earth and Space Chemistry 2, no. 11:1145-1160. PNNL-SA-130781. doi:10.1021/acsearthspacechem.8b00077
  • Pearce C.I., S.A. Saslow, R.M. Asmussen, W. Um, J.N. Serne, M.D. Miller, and O. Qafoku, et al. 2018. "Exploiting Knowledge of Technetium in the Subsurface to Develop Remediation Strategies - 18223." In Proceedings of the 44th Annual Waste Management Conference (WM2018), Nuclear and Industrial Robotics, Remote Systems and Other Emerging Technology, March 18-22, 2018, Phoenix, AZ, 8, 5082-5090. Tempe, Arizona:Waste Management Symposia, Inc. PNNL-SA-130601.

2017

  • Hufschmid R.D., C.J. Newcomb, J.W. Grate, J.J. De Yoreo, N.D. Browning, and N. Qafoku. 2017. "Direct visualization of aggregate morphology and dynamics in a model soil organic-mineral system." Environmental Science & Technology Letters 4, no. 5:186-191. PNNL-SA-124132. doi:10.1021/acs.estlett.7b00068
  • Lawter A.R., N. Qafoku, R.M. Asmussen, D.H. Bacon, L. Zheng, and C.F. Brown. 2017. "Risk of geologic sequestration of CO2 to groundwater aquifers: Current knowledge and remaining questions." Energy Procedia 114. PNNL-SA-121493. doi:10.1016/j.egypro.2017.03.1433
  • Newcomb C.J., N. Qafoku, J.W. Grate, V.L. Bailey, and J.J. De Yoreo. 2017. "Developing a Molecular Picture of Soil Organic Matter-Mineral Interactions by Quantifying Organo-Mineral Binding." Nature Communications 8. PNNL-SA-121086. doi:10.1038/s41467-017-00407-9
  • Qafoku N., A.R. Lawter, D.H. Bacon, L. Zheng, J.E. Kyle, and C.F. Brown. 2017. "Review of the Impacts of Leaking CO2 Gas and Brine on Groundwater Quality"." Earth - Science Reviews 169. PNNL-SA-119041. doi:10.1016/j.earscirev.2017.04.010
  • Strickland C.E., A.R. Lawter, N. Qafoku, J.E. Szecsody, M.J. Truex, and G. Wang. 2017. Evaluation of Iodine Remediation Technologies in Subsurface Sediments: Interim Status Report. PNNL-26957. Richland, WA: Pacific Northwest National Laboratory. doi:10.2172/1418095.Evaluation of Iodine Remediation Technologies in Subsurface Sediments: Interim Status Report
  • Strickland C.E., C.D. Johnson, B.D. Lee, N. Qafoku, J.E. Szecsody, M.J. Truex, and V.R. Vermeul. 2017. Identification of Promising Remediation Technologies for Iodine in the UP-1 Operable Unit. PNNL-26934. Richland, WA: Pacific Northwest National Laboratory. doi:10.2172/1418096.Identification of Promising Remediation Technologies for Iodine in the UP-1 Operable Unit
  • Truex M.J., J.E. Szecsody, N. Qafoku, C.E. Strickland, J.J. Moran, B.D. Lee, and M. Snyder, et al. 2017. Contaminant Attenuation and Transport Characterization of 200-DV-1 Operable Unit Sediment Samples. PNNL-26208. Richland, WA: Pacific Northwest National Laboratory. doi:10.2172/1368134.Contaminant Attenuation and Transport Characterization of 200-DV-1 Operable Unit Sediment Samples
  • Xu J., H. Veeramani, N. Qafoku, G. Singh, M.V. Riquelme Breazeal, A. Pruden, and R.K. Kukkadapu, et al. 2017. "Efficacy of Acetate-Amended Biostimulation for Uranium Sequestration: Combined Analysis of Sediment/Groundwater Geochemistry and Bacterial Community Structure." Applied Geochemistry 78. PNNL-SA-120349. doi:10.1016/j.apgeochem.2016.12.024
  • Xu J., H. Veeramani, N. Qafoku, G. Singh, M.V. Riquelme Breazeal, A. Pruden, and R.K. Kukkadapu, et al. 2017. "Efficacy of Acetate-Amended Biostimulation for Uranium Sequestration: Combined Analysis of Sediment/Groundwater Geochemistry and Bacterial Community Structure." Applied Geochemistry 78. PNNL-SA-123123. doi:10.1016/j.apgeochem.2016.12.024

2016

  • Andersen A., P.N. Reardon, S.S. Chacon, N. Qafoku, N.M. Washton, and M. Kleber. 2016. "Protein-mineral Interactions: Molecular Dynamics Simulations Capture Importance of Variations in Mineral Surface Composition and Structure." Langmuir 32, no. 24:6194-6209. PNNL-SA-116971. doi:10.1021/acs.langmuir.6b01198
  • Asmussen R.M., J.J. Neeway, A.R. Lawter, A.D. Wilson, and N. Qafoku. 2016. "Silver Based Getters for 129-I Removal from Low Activity Wastes." Radiochimica Acta 104, no. 12:905-913. PNNL-SA-116202. doi:10.1515/ract-2016-2598
  • Asmussen R.M., J.J. Neeway, A.R. Lawter, T.G. Levitskaia, W.W. Lukens, and N. Qafoku. 2016. "The Function of Sn(II)-Apatite as a 99-Tc Immobilizing Agent." Journal of Nuclear Materials 480. PNNL-SA-114465. doi:10.1016/j.jnucmat.2016.09.002
  • Bacon D.H., N. Qafoku, Z. Dai, E. Keating, and C.F. Brown. 2016. "Modeling the Impact of Carbon Dioxide Leakage into an Unconfined, Oxidizing Carbonate Aquifer." International Journal of Greenhouse Gas Control 44, no. 2016:290-299. PNNL-SA-105184. doi:10.1016/j.ijggc.2015.04.008
  • Gartman B.N., and N. Qafoku. 2016. "Uranium interaction with soil minerals in the presence of co-contaminants: Case Study- subsurface sediments at or below the water table." In Trace Elements in Waterlogged Soils and Sediments. Advances in Trace Elements in the Environment, edited by J Rinklebe, AS Knox and M Paller. 225-249. Boca Raton, Florida:CRC Press. PNNL-SA-103897.
  • Harvey O.R., N. Qafoku, K.J. Cantrell, M.J. Wilkins, and C.F. Brown. 2016. "Methanogenesis-induced pH-Eh shifts drives aqueous metal(loid) mobility in sulfide mineral systems under CO2 enriched conditions." Geochimica et Cosmochimica Acta 173. PNNL-SA-105773. doi:10.1016/j.gca.2015.11.002
  • Neeway J.J., N. Qafoku, B.D. Williams, M. Snyder, C.F. Brown, and E.M. Pierce. 2016. "Evidence of Technetium and Iodine from a Sodalite-Bearing Ceramic Waste Form." Applied Geochemistry 66. PNNL-SA-101989. doi:10.1016/j.apgeochem.2015.12.017
  • Neeway J.J., R.M. Asmussen, A.R. Lawter, M.E. Bowden, W.W. Lukens, D. Sarma, and B.J. Riley, et al. 2016. "Removal of TcO4- from Representative Nuclear Waste Streams with Layered Potassium Metal Sulfide Materials." Chemistry of Materials 28, no. 11:3976-3983. PNNL-SA-116928. doi:10.1021/acs.chemmater.6b01296
  • Qafoku N., and J.E. Amonette. 2016. "Iron Oxides." In Encyclopedia of Soil Science. 3rd Edition, edited by Rattan Lal. 1245-1249. Boca Raton, Florida:Taylor & Francis Group. PNNL-SA-110804.
  • Qafoku N., and R. Sahajpal. 2016. "Subsoil contaminant Cr fate and transport: The complex reality of the Hanford subsurface." In Trace Elements in Waterlogged Soils and Sediments. Advances in Trace Elements in the Environment, edited by J Rinklebe, AS Knox and M Paller. 163-183. Boca Raton, Florida:CRC Press. PNNL-SA-114768.
  • Van Ranst E., N. Qafoku, A. Noble, and R. Xu. 2016. "VARIABLE CHARGE SOILS: MINERALOGY AND CHEMISTRY." In Encyclopedia of Soil Science, edited by Rattan Lal. 2432-2439. Boca Raton, Florida:Taylor & Francis Group. PNNL-SA-110721.
  • Williams B.D., J.J. Neeway, M. Snyder, M.E. Bowden, J.E. Amonette, B.W. Arey, and E.M. Pierce, et al. 2016. "Mineral Assemblage Transformation of a Metakaolin-based Waste Form After Geopolymer Encapsulation." Journal of Nuclear Materials 473. PNNL-SA-98733. doi:10.1016/j.jnucmat.2015.12.023
  • Xu R., N. Qafoku, E. Van Ranst, J. Li, and J. Jiang. 2016. "Adsorption properties of subtropical and tropical variable charge soils: Implications from climate change and biochar amendment." In Advances in Agronomy. 1-58. Amsterdam, :Elsevier. PNNL-SA-113468. doi:10.1016/bs.agron.2015.09.001

2015

  • Gartman B.N., N. Qafoku, J.E. Szecsody, R.K. Kukkadapu, Z. Wang, D.M. Wellman, and M.J. Truex. 2015. "Uranium Fate in Hanford Sediment Altered by Simulated Acid Waste Solutions." Applied Geochemistry 63, no. December 2015:1-9. PNNL-SA-105743. doi:10.1016/j.apgeochem.2015.07.010
  • Lawter A.R., N. Qafoku, G. Wang, H. Shao, and C.F. Brown. 2015. "Evaluating Impacts of CO2 Intrusion into an Unconsolidated Aquifer: I. Experimental Data." International Journal of Greenhouse Gas Control 44, no. 2016:323-333. PNNL-SA-107057. doi:10.1016/j.ijggc.2015.07.009
  • Lawter A.R., N. Qafoku, H. Shao, D.H. Bacon, and C.F. Brown. 2015. "Evaluating Impacts of CO2 and CH4 Gas Intrusion into an Unconsolidated Aquifer: Fate of As and Cd." Frontiers in Environmental Science 3. PNNL-SA-110137. doi:10.3389/fenvs.2015.00049
  • Mouser P.J., A.L. N'Guessan, N. Qafoku, M. Sinha, K.H. Williams, M. Dangelmayr, and C.T. Resch, et al. 2015. "Influence of Carbon and Microbial Community Priming on the Attenuation of Uranium in a Contaminated Floodplain Aquifer." Groundwater 53, no. 4:600-613. PNNL-SA-99197. doi:10.1111/gwat.12238
  • Neeway J.J., A.R. Lawter, R.J. Serne, R.M. Asmussen, and N. Qafoku. 2015. "Technetium Getters to Improve Cast Stone Performance." In MRS Proceedings: Scientific Basis for Nuclear Waste Management XXXVIII, edited by S Gin, R Jubin, J Matyas and E Vance, 1744, 43-52. Warrendale, Pennsylvania:Materials Research Society. PNNL-SA-106863. doi:10.1557/opl.2015.310
  • Neeway J.J., N. Qafoku, R.J. Serne, A.R. Lawter, J.R. Stephenson, W.W. Lukens, and J.H. Westsik. 2015. Evaluation of Technetium Getters to Improve the Performance of Cast Stone. PNNL-23667 Rev. 1;EMSP-RPT-026 Rev1. Richland, WA: Pacific Northwest National Laboratory. Evaluation of Technetium Getters to Improve the Performance of Cast Stone
  • Qafoku N. 2015. "Climate-change effects on soils: Accelerated weathering, soil carbon and elemental cycling." In Advances in Agronomy, edited by DL Sparks. 111-172. Amsterdam:Elsevier. PNNL-SA-102998.
  • Reiser J.T., L. Neill, J.L. Weaver, B. Parruzot, C. Musa, J.J. Neeway, and J.V. Ryan, et al. 2015. "Glass corrosion in the presence of iron-bearing materials and potential corrosion suppressors." In Scientific Basis for Nuclear Waste Management XXXVIII. MRS Proceedings, edited by S Gin, R Jubin, J Matyas and E Vance, 1744, 139-144. Cambridge:Materials Research Society. PNNL-SA-108398. doi:10.1557/opl.2015.503
  • Shao H., N. Qafoku, A.R. Lawter, M.E. Bowden, and C.F. Brown. 2015. "Coupled Geochemical Impacts of Leaking CO2 and Contaminants from Subsurface Storage Reservoirs on Groundwater Quality." Environmental Science & Technology 49, no. 13:8202-8209. PNNL-SA-108351. doi:10.1021/acs.est.5b01004
  • Szecsody J.E., M.J. Truex, L. Zhong, J.P. McKinley, N. Qafoku, B.D. Lee, and S.D. Saurey. 2015. "Remediation of Technetium in Vadose Zone Sediments Using Ammonia and Hydrogen Sulfide Gases." Vadose Zone Journal 14, no. 7. PNNL-SA-107578. doi:10.2136/vzj2014.09.0134
  • Wang G., N. Qafoku, A.R. Lawter, M.E. Bowden, O. Harvey, E.C. Sullivan, and C.F. Brown. 2015. "Geochemical Impacts of Leaking CO2 from Subsurface Storage Reservoirs to an Unconfined Oxidizing Carbonate Aquifer." International Journal of Greenhouse Gas Control 44, no. 2016:310-322. PNNL-SA-96349. doi:10.1016/j.ijggc.2015.07.002
  • Zheng L., N. Qafoku, A.R. Lawter, G. Wang, H. Shao, and C.F. Brown. 2015. "Evaluating Impacts of CO2 Intrusion into an Unconsolidated Aquifer: II. Modeling Results." International Journal of Greenhouse Gas Control 44, no. 2016:300-309. PNNL-SA-106872. doi:10.1016/j.ijggc.2015.07.001

2014

  • Namgung S., M. Kwon, N. Qafoku, and G. Lee. 2014. "Cr(OH)3(s) Oxidation Induced by Surface Catalyzed Mn(II) Oxidation." Environmental Science & Technology 48, no. 18:10760-10768. PNNL-SA-101626. doi:10.1021/es503018u
  • Neeway J.J., N. Qafoku, B.D. Williams, K.A. Rod, M.E. Bowden, C.F. Brown, and E.M. Pierce. 2014. "Performance of the Fluidized Bed Steam Reforming Product Under Hydraulically Unsaturated Conditions." Journal of Environmental Radioactivity 131. PNNL-SA-96489. doi:10.1016/j.jenvrad.2013.10.008
  • Qafoku N., A.R. Lawter, H. Shao, G. Wang, and C.F. Brown. 2014. "Evaluating impacts of CO2 gas intrusion into a confined sandstone aquifer: Experimental results." Energy Procedia 63. PNNL-SA-105260. doi:10.1016/j.egypro.2014.11.355
  • Qafoku N., B.N. Gartman, R.K. Kukkadapu, B.W. Arey, K.H. Williams, P.J. Mouser, and S.M. Heald, et al. 2014. "Geochemical and Mineralogical Investigation of Uranium in Multi-element Contaminated, Organic-rich Subsurface Sediment." Applied Geochemistry 42. PNNL-SA-86519. doi:10.1016/j.apgeochem.2013.12.001

2013

  • Harvey O.R., N. Qafoku, K.J. Cantrell, G. Lee, J.E. Amonette, and C.F. Brown. 2013. "Geochemical Implications of Gas Leakage Associated with Geologic CO2 Storage - A Qualitative Review." Environmental Science & Technology 47, no. 1:23-36. PNNL-SA-83207. doi:10.1021/es3029457
  • Neeway J.J., N. Qafoku, C.F. Brown, and R.A. Peterson. 2013. "Characterization and Leaching Tests of the Fluidized Bed Steam Reforming (FBSR) Waste Form for LAW Immobilization." In Proceedings of the Annual Waste Management Symposium (WM2013): International Collaboration and Continuous Improvement, February 24-28, 2013, Phoenix, Arizona, 3, 2268-2275, Paper No. 13400. Tucson, Arizona:WM Symposia. PNNL-SA-91992.
  • Szecsody J.E., M.J. Truex, N. Qafoku, D.M. Wellman, C.T. Resch, and L. Zhong. 2013. "Influence of Acidic and Alkaline Waste Solution Properties on Uranium Migration in Subsurface Sediments." Journal of Contaminant Hydrology 151. PNNL-SA-96107. doi:10.1016/j.jconhyd.2013.05.009
  • Veeramani H., H. Veeramani, A. Scheinost, N. Monsegue, N. Qafoku, R.K. Kukkadapu, and M. Newville, et al. 2013. "Abiotic Reductive Immobilization of U(VI) by Biogenic Mackinawite." Environmental Science & Technology 47, no. 5:2361-2369. PNNL-SA-91214. doi:10.1021/es304025x

2012

  • Campbell K.M., R.K. Kukkadapu, N. Qafoku, A.D. Peacock, E. Lesher, K.H. Williams, and J.R. Bargar, et al. 2012. "Geochemical, mineralogical and microbiological characteristics of sediment from a naturally reduced zone in a uranium-contaminated aquifer." Applied Geochemistry 27, no. 8:1499-1511. PNNL-SA-85044. doi:10.1016/j.apgeochem.2012.04.013
  • Neeway J.J., N. Qafoku, B.D. Williams, M.M. Valenta, E.A. Cordova, S.C. Strandquist, and D.C. Dage, et al. 2012. "Single Pass Flow-Through (SPFT) Test Results of Fluidized Bed Steam Reforming (FBSR) Waste Forms used for LAW Immobilization." In Waste Management Symposium (WM 2012): Improving the Future in Waste Management, February 26 - March 1, 2012, Phoenix, Arizona, Paper No. 12252. Tucson, Arizona:Waste Management Symposia, Inc. PNNL-SA-84289.
  • Neeway J.J., N. Qafoku, J.H. Westsik, C.F. Brown, C. Jantzen, and E.M. Pierce. 2012. "Radionuclide and contaminant immobilization in the fluidized bed steam reforming waste products." In Radioactive Waste, edited by RA Rahman. 239-262. Rijeka:InTech Europe. PNNL-SA-83289.
  • Qafoku N. 2012. "Impacts of Environmental Nanoparticles on Chemical, Biological and Hydrological Processes in Terrestrial Ecosystems." In Handbook of Soil Sciences: Resource Management and Environmental Impacts, 2nd Edition, edited by PM Huang, Y Li and ME Sumner. 4.1- 4.17. Boca Raton, Florida:CRC Press. PNNL-SA-69713.
  • Szecsody J.E., M.J. Truex, L. Zhong, T.C. Johnson, N. Qafoku, M.D. Williams, and W.J. Greenwood, et al. 2012. "Geochemical and Geophysical Changes during Ammonia Gas Treatment of Vadose Zone Sediments for Uranium Remediation." Vadose Zone Journal 11, no. 4. PNNL-SA-86840. doi:10.2136/vzj2011.0158
  • Um W., H. Chang, J.P. Icenhower, W.W. Lukens, R.J. Serne, N. Qafoku, and R.K. Kukkadapu, et al. 2012. "Iron Oxide Waste Form for Stabilizing 99Tc." Journal of Nuclear Materials 429, no. 1-3:201-209. PNNL-SA-86045. doi:10.1016/j.jnucmat.2012.06.004

2011

  • Um W., H. Chang, J.P. Icenhower, W.W. Lukens, R.J. Serne, N. Qafoku, and J.H. Westsik, et al. 2011. "Immobilization of 99-Technetium (VII) by Fe(II)-Goethite and Limited Reoxidation." Environmental Science & Technology 45, no. 11:4904-4913. PNNL-SA-72463. doi:10.1021/es104343p

2010

  • Cabrera M.L., D.E. Kissel, J.R. Craig, N. Qafoku, N. Vaio, J.A. Rema, and L.A. Morris. 2010. "Relative Humidity Controls Ammonia Loss from Urea Applied to Loblolly Pine." Soil Science Society of America Journal 74, no. 2:543-549. PNNL-SA-69712.
  • 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
  • Kukkadapu R.K., N. Qafoku, B.W. Arey, C.T. Resch, and P.E. Long. 2010. "Effect of Extent of Natural Subsurface Bioreduction on Fe-mineralogy of Subsurface Sediments." Journal of Physics: Conference Series 217, no. 1:012047 1-8. PNNL-SA-69002. doi:10.1088/1742-6596/217/1/012047
  • Qafoku N. 2010. "Terrestrial nanoparticles and their controls on soil/geo processes and reactions." In Advances in Agronomy, edited by Donald Sparks. 33-91. San Diego, California:Academic Press. PNNL-SA-71573.
  • Qafoku N., P.E. Dresel, E.S. Ilton, J.P. McKinley, and C.T. Resch. 2010. "Chromium transport in an acidic waste contaminated subsurface medium: The role of reduction." Chemosphere 81, no. 11:1492-1500. PNNL-SA-71074. doi:10.1016/j.chemosphere.2010.08.043

2009

  • Fiantis D., M. Nelson, E. Van Ranst, J. Shamshudin, and N. Qafoku. 2009. "Chemical Weathering of New Pyroclastic Deposits from Mt. Merapi (Java), Indonesia." Journal of Mountain Science 6, no. 3:240-254. PNNL-SA-68135.
  • Qafoku N., L. Zhong, C.J. Thompson, C. Liu, B.W. Arey, A.V. Mitroshkov, and R.G. Riley. 2009. "Physical control on CCl4 and CHCl3 desorption from artificially contaminated and aged sediments with supercritical carbon dioxide." Chemosphere 74, no. 4:494-500. PNNL-SA-60227.
  • Qafoku N., P.E. Dresel, J.P. McKinley, C. Liu, S.M. Heald, C.C. Ainsworth, and J.L. Phillips, et al. 2009. "Pathways of aqueous Cr(VI) attenuation in a slightly alkaline oxic subsurface." Environmental Science & Technology 43, no. 4:1071-1077. PNNL-SA-62386.
  • Qafoku N., R.K. Kukkadapu, J.P. McKinley, B.W. Arey, S.D. Kelly, C.M. Wang, and C.T. Resch, et al. 2009. "Uranium in Framboidal Pyrite from a Naturally Bioreduced Alluvial Sediment." Environmental Science & Technology 43, no. 22:8528-8534. PNNL-SA-65650. doi:10.1021/es9017333
  • Zhong L., N. Qafoku, J.E. Szecsody, P.E. Dresel, and Z.F. Zhang. 2009. "Foam Delivery of Calcium Polysulfide to Vadose Zone for Chromium-VI Immobilization: A Laboratory Evaluation." Vadose Zone Journal 8, no. 4:976-985. PNNL-SA-60896. doi:10.2136/vzj2008.0124

2008

  • 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
  • Qafoku N., and J.P. Icenhower. 2008. "Interactions of Aqueous U(VI) with Soil Minerals in Slightly Alkaline Natural Systems." Re/views in Environmental Science and Bio/technology 7, no. 4:355-380. PNNL-SA-58096. doi:10.1007/s11157-008-9137-8
  • Van Ranst E., S.R. Utami, A. Verdoodt, A. Verdoodt, and N. Qafoku. 2008. "Mineralogy of a perudic Andosol in central Java, Indonesia." Geoderma 144. PNNL-SA-58368.
  • 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

2007

  • Qafoku N., C.C. Ainsworth, and S.M. Heald. 2007. "Cr(VI) Fate in Mineralogically Altered Sediments by Hyperalkaline Waste Fluids." Soil Science 172, no. 8:598-613. PNNL-SA-52078.
  • Qafoku N., O. Qafoku, C.C. Ainsworth, A. Dohnalkova, and S.G. McKinley. 2007. "Fe-Solid Phase Transformations Under Highly Basic Conditions." Applied Geochemistry 22, no. 9:2054-2064. PNNL-SA-51570. doi:10.1016/j.apgeochem.2007.04.023

2005

  • 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
  • Qafoku N., M.E. Sumner, and M. Toma. 2005. "Ion Transport Dynamics in Acid Variable Charge Subsoils." Soil Science and Plant Nutrition 51, no. 5:601-603. PNNL-SA-44875.

2004

  • Qafoku N., C.C. Ainsworth, J.E. Szecsody, and O. Qafoku. 2004. "Transport-controlled kinetics of dissolution and precipitation in the sediments under alkaline and saline conditions." Geochimica et Cosmochimica Acta 68, no. 14:2981-2995. PNNL-SA-38913.
  • Qafoku N., E. Van Ranst, A. Noble, and G. Baert. 2004. "Variable Charge Soils: Their Mineralogy, Chemistry and Management." In Advances in Agronomy, edited by Donald L. Sparks. 159-215. San Diego, California:Academic Press. PNWD-SA-6396.

2003

  • Qafoku N., C.C. Ainsworth, J.E. Szecsody, and O. Qafoku. 2003. "Aluminum Effect on Dissolution and Precipitation under Hyperalkaline Conditions: I. Liquid Phase Transformations." Journal of Environmental Quality 32, no. 6:2354-2369. PNNL-SA-36190.
  • Qafoku N., C.C. Ainsworth, J.E. Szecsody, D.L. Bish, J.S. Young, D.E. McCready, and O. Qafoku. 2003. "Aluminum Effect on Dissolution and Precipitation under Hyperalkaline Conditions: II. solid Phase Transformations." Journal of Environmental Quality 32, no. 6:2364-2372. PNNL-SA-36191.
  • Qafoku N., C.C. Ainsworth, J.E. Szecsody, O. Qafoku, and S.M. Heald. 2003. "Effect of Coupled Dissolution and Redox Reactions on Cr(VI)(aq) Attenuation during Transport in the Sediments under Hyperalkaline Conditions." Environmental Science & Technology 37, no. 16:3640-3646. PNNL-SA-36318.
  • Qafoku N., E. Van Ranst, A. Noble, and G. Baert. 2003. "Variable Charge Soils: Mineralogy and Chemistry." In Encyclopedia of Soil Science, edited by Rattan Lal. 1822 - 1829. Oxford:Taylor and Francis Group. PNWD-SA-5861.

Energy and Environment

Core Research Areas

Contacts