USGS - science for a changing world

USGS Professional Pages

Blank space
Search USGS Professionals Featured Profiles Blank space Frequently Asked Questions  |  About The USGS Professional Pages
bio image of Douglas  Kent

Douglas Kent

Hydrologist

Contact Info


Short Biography

Doug Kent received a BA in chemistry from the University of California, San Diego and a PhD from Scripps Institution of Oceanography.  He has conducted hydrologic research at the USGS since 1985.



Read Full Professional Summary

Publications

Amirbahman, A.; Kent, D. B.; Curtis, G. P., Marvin-DiPasquale, M. C., 2013, Kinetics of homogeneous and surface-catalyzed mercury(II) reduction by iron(II), Environmental Science and Technology, v. 47, n. 13, p. 7204-7213, DOI: 10.1021/es401459p. [Link]

Stoliker, D.L., Kaviani, N., Kent, D.B., Davis, J.A., 2013. Evaluating ion exchange resin efficiency and oxidative capacity for the separation of uranium(IV) and uranium(VI). Geochemical Transactions, v.14, doi:10.1186/1467-4866-14-1. [Link]

Stoliker, D. L., Campbell, K. M., Fox, P. M., Singer, D. M., Kaviani, N., Carey, M., Peck, N. E., Bargar, J. R., Kent, D. B., Davis, J. A., 2013, Evaluating chemical extraction techniques for the determination of uranium oxidation state in reduced aquifer sediments, Environmental Science and Technology, v. 47, p. 9225-9232, DOI: 10.1021/es401450v. [Link]

Stoliker, D.L.; Liu, C.; Kent, D. B.; Zachara, J. M.,2013, Characterizing particle-scale equilibrium adsorption and kinetics of uranium(VI) desorption from U-contaminated sediments, Water Resources Research, v. 49, p. 1163-1177, DOI10.1002/wrcr.20104 [Link]

Lamborg, C.H., Kent, D.B., Swarr, G.J., Munson, K.W., Kading, T., O'Connor, A.E., Fairchild, G.M., LeBlanc, D.R., Wiatrowski, H.A., 2013, Mercury speciation and mobilization in a wastewater-contaminated groundwater plume: Environmental Science and Technology, v. 47, p. 13239−13249. [Link]

Savoie, J.G., LeBlanc, D.R., Fairchild, G.M., Smith, R.L., Kent, D.B., Barber, L.B., Repert, D.A., Hart, C.P., Keefe, S.H., and Parsons, L.A., 2012, Groundwater-quality data for a treated-wastewater plume near the Massachusetts Military Reservation, Ashumet Valley, Cape Cod, Massachusetts, 2006–08: U.S. Geological Survey Data Series 648, 11 p. [Link]

Yin, J., Haggerty, R., Stoliker, D. L., Kent, D. B., Istok, J. D., Greskowiak, J., and Zachara, J. M., 2011, Transient groundwater chemistry near a river: Effects on U(VI) transport in laboratory column experiments: Water Resources Research, v. 47, n. 4, W04502, doi:10.1029/2010WR009369. [Link]

Stoliker, D. L., Kent, D. B., and Zachara, J. M., 2011, Quantifying differences in the impact of variable chemistry on equilibrium uranium(VI) adsorption properties of aquifer sediments, Environmental Science and Technology, v. 45, p. 8733-8740. [Link]

Zhang, S., Kent, D. B., Elbert, D. C., Shi, Z., Davis, J. A., and Veblen, D. R., 2011, Mineralogy, morphology, and textural relationships in coatings on quartz grains in sediments in a quartz-sand aquifer: Journal of Contaminant Hydrology, v. 124, n. 1-4, p. 57-67. [Link]

Fox, P.M., Kent, D.B., and Davis, J.A., 2010. Redox transformations and transport of cesium and iodine (-1, 0, +5) in oxidizing and reducing zones of a sand and gravel aquifer, Environmental Science & Technology, v. 44, no. 6, p. 1940-1946. [Link]

Barnett, M.O., and Kent, D.B., eds., 2008, Adsorption of Metals by Geomedia II: Variables, Mechanisms, and Model Applications : Amsterdam, Elsevier, 474 p. [Link]

Kent, D.B., Davis, J.A., Joye, J.L., and Curtis, G.P., 2008, Influence of variable chemical conditions on EDTA-enhanced transport of metal ions in mildly acidic groundwater: Environmental Pollution, v. 153, no. 1, p. 44-52. [Link]

Kent, D.B., Wilkie, J.A., and Davis, J.A., 2007, Modeling the movement of a pH perturbation and its impact on adsorbed zinc and phosphate in a wastewater-contaminated aquifer: Water Resources Research, v. 43, W07440, doi:10.1029/2005WR004841. [Link]

Savoie, Jennifer G.; Smith, Richard L.; Kent, Douglas B.; Hess, Kathryn M.; LeBlanc, Denis R.; Barber, Larry B., 2006. Ground-Water-Quality Data for a Treated-Wastewater Plume Undergoing Natural Restoration, Ashumet Valley, Cape Cod, Massachusetts, 1994-2004. Data Series 198, CD-ROM [Link]

Amirbahman, A., Kent, D.B., Curtis, G.P., and Davis, J.A. 2006, Kinetics of sorption and abiotic oxidation of arsenic(III) by aquifer materials: Geochimica et Cosmochimica Acta, v. 70, p. 533-547. [Link]

Höhn, R., Isenbeck-Schröter, M., Kent, D.B., Davis, J.A., Jakobsen, R., Jann, S., Niedan, V., Scholz, C., Stadler, S., and Tretner, A., 2006, Tracer test with As(V) under variable redox conditions controlling arsenic transport in the presence of elevated ferrous iron concentrations: Journal of Contaminant Hydrology, v. 88, p. 36-54. [Link]

Repert, D.A., Barber, L.B., Hess, K.M., Keefe, S.H., Kent, D.B., LeBlanc, D.R., and Smith, R.L., 2006, Long-term natural attenuation of carbon and nitrogen within a groundwater plume after removal of the treated wastewater source: Environmental Science and Technology, v. 40, p. 1,154-1,162. [Link]

Savoie, Jennifer G.; Kent, Douglas B.;S mith, Richard L.; LeBlanc, Denis R.; Hubble, David W., 2004. Changes in Ground-Water Quality near Two Granular-Iron Permeable Reactive Barriers in a Sand and Gravel Aquifer, Cape Cod, Massachusetts, 1997-2000. Water-Resources Investigations Report 2003-4309, 84 p. [Link]

Kent, D.B., and Fox, P. M., 2004, The influence of groundwater chemistry on arsenic concentrations and speciation in a quartz sand and gravel aquifer: Geochemical Transactions, v. 5, p. 1-12 [Link]

McCobb, Timothy D.; LeBlanc, Denis R.; Walter, Donald A.; Hess, Kathryn M.; Kent, Douglas B.; Smith, Richard L., 2003. Phosphorus in a ground-water contaminant plume discharging to Ashumet Pond, Cape Cod, Massachusetts, 1999. Water-Resources Investigations Report 2002-4306, 77 p. [Link]

Kent, D. B., Davis, J.A., Anderson, L.C.D., Rea, B.A., and Coston, J.A., 2002, Effect of adsorbed metal ions on the transport of Zn- and Ni-EDTA complexes in a sand and gravel aquifer: Geochimica et Cosmochimica Acta, v. 66, no. 17, p. 3,017-3,036. [Link]

Hess, K. M., Davis, J.A., Kent, D.B., and Coston, J.A., 2002, Multispecies reactive tracer test in an aquifer with spatially variable chemical conditions, Cape Cod, Massachusetts: Dispersive transport of bromide and nickel: Water Resources Research, v. 38, no. 8, p. 36-1 to 36-17. [Link]

Friedly, J.C., Kent, D.B., and Davis, J.A., 2002, Simulation of the mobility of metal-EDTA complexes in groundwater: The influence of contaminant metals: Environmental Science and Technology, v. 36, no. 3, p. 355-363. [Link]

Davis, J. A., Coston, J. A., Kent, D. B., Hess, K. M., Joye, J. L., Brienen, P., and Campo, K. W., 2001b, Multispecies reactive transport in a sand and gravel aquifer, Cape Cod, Massachusetts, Part 2. Transport of chromium(VI) and lead-, copper-, and zinc-EDTA complexes: U. S. Environmental Protection Agency Research Brief, EPA/600/R-01/007b, Cincinnati, OH, 47p. [Link]

Davis, J. A., Hess, K. M., Coston, J. A., Kent, D. B., Joye, J. L., Brienen, P., and Campo, K. W., 2001a, Multispecies reactive transport in a sand and gravel aquifer, Cape Cod, Massachusetts, Part 1. Experimental design and transport of bromide and nickel-EDTA tracers: U. S. Environmental Protection Agency Research Brief, EPA/600/R-01/007a, Cincinnati, OH, 38p. [Link]

Kent, D. B., Abrams, R. H., Davis, J. A., Coston, J. A., and LeBlanc, D. R., 2000, Modeling the influence of variable pH on the transport of zinc in a contaminated aquifer using semiempirical surface complexation models: Water Resources Research, v. 36, no. 12, p. 3411-3425. [Link]

Davis, J.A., Kent, D.B., Coston, J.A., Hess, K. M., and Joye, J., 2000, Multispecies reactive tracer test in an aquifer with spatially variable chemical conditions: Water Resources Research, v. 36, no. 1, p. 119-134. [Link]

Davis, J. A., Kent, D. B., Coston, J. A., Hess, K. M, and Joye, J., 1999, Multispecies reactive transport in an aquifer with spatially variable chemical conditions: An overview, Morganwalp, D.W., and Buxton, H.T., eds., U.S. Geological Survey Toxic Substances Hydrology Program--Proceedings of the Technical Meeting, Charleston, South Carolina, March 8-12, 1999 -- Volume 3 -- Subsurface Contamination from Point Sources: U.S. Geological Survey Water-Resources Investigations Report 99-4018C, p. 383-392.

Davis, J. A., Kent, D. B., Coston, J. A., Hess, K. M, and Joye, J., 1999, Multispecies reactive transport in an aquifer with spatially variable chemical conditions: An overview, Morganwalp, D.W., and Buxton, H.T., eds., U.S. Geological Survey Toxic Substances Hydrology Program--Proceedings of the Technical Meeting, Charleston, South Carolina, March 8-12, 1999 -- Volume 3 -- Subsurface Contamination from Point Sources: U.S. Geological Survey Water-Resources Investigations Report 99-4018C, p. 383-392.

LeBlanc, D. R., Hess, K. M, Kent, D. B., Smith, R. L., Barber, L. B., and Campo, K. W., 1999, Natural restoration of a sewage plume in a sand and gravel aquifer, Cape Cod, Massachusetts, Morganwalp, D.W., and Buxton, H.T., eds., U.S. Geological Survey Toxic Substances Hydrology Program--Proceedings of the Technical Meeting, Charleston, South Carolina, March 8-12, 1999 -- Volume 3 -- Subsurface Contamination from Point Sources: U.S. Geological Survey Water-Resources Investigations Report 99-4018C, p. 245-259. [Link]

Kent D. B. and Maeder, V., 1999, Evolution of a ground-water sewage plume after removal of the 60-year-long source, Cape Cod, Massachusetts: pH and fate of phosphate and metals, Morganwalp, D.W., and Buxton, H.T., eds., U.S. Geological Survey Toxic Substances Hydrology Program--Proceedings of the Technical Meeting, Charleston, South Carolina, March 8-12, 1999 -- Volume 3 -- Subsurface Contamination from Point Sources: U.S. Geological Survey Water-Resources Investigations Report 99-4018C, p. 293-304. [Link]

Kent, D. B., Davis, J. A., Abrams, R. H., and Coston, J. A., 1999, Modeling the influence of adsorption on the fate and transport of metals in shallow ground water: zinc contamination in the sewage plume on Cape Cod, Massachusetts, Morganwalp, D.W., and Buxton, H.T., eds., U.S. Geological Survey Toxic Substances Hydrology Program--Proceedings of the Technical Meeting, Charleston, South Carolina, March 8-12, 1999 -- Volume 3 -- Subsurface Contamination from Point Sources: U.S. Geological Survey Water-Resources Investigations Report 99-4018C, p. 361-369. [Link]

Kent, D. B., 1998, Effects of pumping rate and filtration on concentrations of inorganic solutes, in Savoie, J., and LeBlanc, D. R., eds., Water-quality data and methods of analysis for samples collected near a plume of sewage-contaminated ground water, Ashumet Valley, Cape Cod, Massachusetts, 1993-94: U.S. Geological Survey Water-Resources Investigations Report 97-4269, p. 11-15. [Link]

Abrams, R.H., Loague, Keith, and Kent, D.B., 1998, Development and testing of a compartmentalized reaction network model for redox zones in contaminated aquifers: Water Resources Research, v. 34, no. 6, p. 1531-1541. [Link]

Davis, J.A., Coston, J.A., Kent, D.B., and Fuller, C.C., 1998, Application of the surface complexation concept to complex mineral assemblages: Environmental Science and Technology, v. 32, no. 19, p. 2820-2828. [Link]

Hess, K.M., LeBlanc, D.R., Kent, D.B., and Smith, R.L., 1996, Natural restoration of a sewage-contaminated aquifer, Cape Cod, Massachusetts, in Hydrology and hydrogeology of urban and urbanizing areas, proceedings of the conference, Boston, Mass., April 21-24, 1996: Minneapolis, Minnesota, American Institute of Hydrology, p. WQE13-WQE25.

Kohler, M., Curtis, G. P., Kent, D. B., and Davis, J. A., 1996, Experimental investigation and modeling of uranium(VI) transport under variable chemical conditions, Water Resources Research, v. 32, no. 12, 3539-3551. [Link]

Rea, B. A., Kent, D. B., Anderson, L. C. D., Davis, J. A., and LeBlanc, D., 1996, The transport of inorganic contaminants from a sewage plume in the Cape Cod Aquifer, Massachusetts: in Mallard, G. E., ed., U. S. Geological Survey Toxic Substances Hydrology Program--Proceedings of the technical meeting, Colorado Springs, Colorado, September, 1993: U.S. Geological Survey Water-Resources Investigations Report 94-4015, v. 1, p. 191-198. [Link]

Davis, J.A., Kent, D.B., Coston, J.A., and Hess, K.M., 1996, Heavy-metal transport in a sand and gravel aquifer with variable chemical conditions, Cape Cod, Massachusetts, in Morganwalp, D.W., and Aronson, D.A., eds., U.S. Geological Survey Toxic Substances Hydrology Program--Proceedings of the technical meeting, Colorado Springs, Colorado, September 20-24, 1993: U.S. Geological Survey Water-Resources Investigations Report 94-4015, v. 1, p. 219-225. [Link]

Friedly, J. C., Davis, J. A., and Kent, D. B., 1995, Modeling hexavalent chromium reduction in groundwater in field-scale transport and laboratory batch experiments, Water Resources Research, v. 31, no. 11, 2783-2794.. [Link]

Kent, D. B., Davis, J. A., Anderson, L. D., and Rea, B. A., 1995, Transport of chromium and selenium in the pristine zone of a shallow aquifer: influence of adsorption processes, Water Resources Research, v. 31, no. 4, 1041-1050. [Link]

Kent, D. B., Davis, J. A., Anderson, L. D., Rea, B. A., and Waite, T. D., 1994, Transport of chromium and selenium in the suboxic zone of a shallow aquifer: influence of redox and adsorption reactions, Water Resources Research v. 30, no. 4, 1099-1114. [Link]

Anderson, L. C. D., Kent, D. B., and Davis, J. A., 1994, Batch experiments characterizing the reduction of Cr(VI) using suboxic material from a mildly reducing sand and gravel aquifer, Environmental Science and Technology, v. 28, 178-185. [Link]

Davis, J. A., Kent, D. B., Rea, B. A., Maest, A. S., and Garabedian, S. P., 1993, Influence of redox environment and aqueous speciation on metal transport in groundwater: preliminary results of tracer injection studies: in Metals in Groundwater, Allen, H., Brown, D., and Perdue, E. M., eds., Lewis Publishers, Chelsea, MI, p. 223-273.

Davis, J. A., Waite, T. D., Kent, D. B., and Anderson, L. D. C., 1991, Reduction of chromium(VI) under mildly reducing conditions in a shallow, sand and gravel aquifer: in Mallard, G. E., ed., U. S. Geological Survey Toxic Substances Hydrology Program--Proceedings of the technical meeting, Monterey, California, March 11-15, 72-77.

Rea, B. A., Kent, D. B., LeBlanc, D. R., and Davis, J. A., 1991, Mobility of zinc in a sewage-contaminated aquifer, Cape Cod, Massachusetts: in Mallard, G. E., and Aranson, D. A., eds., U. S. Geological Survey Toxic Substances Hydrology Program--Proceedings of the technical meeting, Monterey, California, March 11-15, 88-95.

Davis, J. A., Kent, D. B., Rea, B. A., Garabedian, S. P., 1991, and Anderson, L. C. D., Influence of the geochemical environment on heavy metal transport in ground water: in Mallard, G. E., ed., U. S. Geological Survey Toxic Substances Hydrology Program--Proceedings of the technical meeting, Monterey, California, March 11-15, p. 72-77.

Anderson, L. D., Kent, D. B., and Davis, J. A., 1991, Adsorption and reduction of Cr(VI) under oxic conditions in a shallow, sand and gravel aquifer in Cape Cod, Massachusetts: in Mallard, G. E., ed., U. S. Geological Survey Toxic Substances Hydrology Program--Proceedings of the technical meeting, Monterey, California, March 11-15, p. 63-71.

Kent, D. B., Davis, J. A., Anderson, L. D., and Rea, B. A., 1991, Transport of zinc in the presence of a strong complexing agent in a shallow aquifer on Cape Cod, Massachusetts: in Mallard, G. E., ed., U. S. Geological Survey Toxic Substances Hydrology Program--Proceedings of the technical meeting, Monterey, California, March 11-15, p. 78-83.

Davis, J. A., and Kent, D. B., 1990, Surface complexation modeling in aqueous geochemistry: in Hochella, M. F., and White, A. F., eds., Mineral-water Interface Geochemistry, Reviews in Mineralogy, v. 23, pp. 177-260. [Link]

Davis, J. A., Kent, D. B., and Rea, B. A., 1989, Field and laboratory studies of coupled flow and chemical reactions in the ground‑water environment: in Mallard, G. E. and Ragone, S. E., eds., U. S. Geological Survey Toxic Substances Hydrology Program--Proceedings of the technical meeting, Phoenix, Arizona, September 26-30, 1988: U. S. Geological Survey Water-Resources Investigations Report 88-4220.

Kent, D. B., Tripathi, V. S., Ball, N. B., and Leckie, J. O., 1986, Surface‑complexation modeling of radionuclide adsorption in sub‑surface environments: Dept. Civil Engineering Tech. Rept. # 294, Stanford University, Stanford, California, 110p; also NUREG/CR‑ 4807(SAND86‑7175), Sandia National Laboratory, New Mexico.

Kent, D. B., and Kastner, M., 1985, Mg2+ removal in the system Mg2+‑amorphous SiO2‑H2O by adsorption and Mg‑hydroxysilicate precipitation: Geochimica et Cosmochimica Acta, v. 49, p. 1123‑1136. [Link]

Kent, D. B., On the surface chemical properties of synthetic and biogenic amorphous silica: Ph.D. dissertation, Scripps Institution of Oceanography, University of California at San Diego, La Jolla, California, 420 pgs., 1983.






                           

My Science Topics


Science Topic
Subtopic
Environmental Issuesground-water quality
Environmental Issueshuman impacts
Environmental Issuestoxic radionuclides
Environmental Issuestoxic trace elements
Environmental Issueswaste treatment and disposal
Environmental Issueswater quality


Understanding the impact of mineral-water interface reactions on contaminant mobility

Image of Current Focus for Understanding the impact of mineral-water interface reactions on contaminant mobility

The objectives of my research are to develop a fundamental understanding of chemical reactions at mineral-water interfaces, to understand the coupling between these reactions and physical and biological processes, and to develop conceptual and quantitative models that are broadly applicable to understanding and predicting metal and metalloid transport, mobilization, and sequestration in groundwater across the range of spatial and temporal scales required in field applications.  Critical elements include understanding properties of natural materials that control chemical reactivity, developing conceptual and quantitative models that describe mineral-water interface reactions, and applying these models in reactive transport simulations at the field-scale.  We have applied these approaches to improve understanding of the mobility of many groundwater contaminants, including arsenic, cesium, chromium, copper, iodine, lead, nickel, uranium, and zinc.

Chemical reactivity of natural sediments is often controlled by constituents of sediment-grain coatings, which can consist of nanometer-scale materials with variable composition and degree of crystallinity.  Advanced molecular and microscopic methods are used to characterize sorbent phases and sorbed metal speciation.  These methods are applied in conjunction with more broadly accessible macroscopic methods to advance understanding of chemical properties of natural materials.  Laboratory experimental studies of solute uptake and release are conducted with both natural materials and synthetic analogues.  Models that can account for the impact of variable chemistry on solute uptake and release are developed.

Conceptual and, where possible, quantitative models of contaminant metal-ion release, transport, and uptake are tested using field studies.  Field studies include characterization studies and field manipulation experiments.  Field characterization studies involve determining the spatial and temporal distributions of fluid- and solid-phase contaminant concentrations and, where possible, chemical speciation of sorbed contaminants.  In addition we need to understand the spatial and temporal distributions of solutes that influence chemical speciation of contaminants, such as pH and the concentrations of redox-reactive species.  Some field manipulation studies involve injecting reactive solutes under well-understood biogeochemical conditions and observing solute concentrations and speciation over time and space.  Other field manipulation studies involve perturbing local biogeochemical conditions and determining the impact on contaminant concentrations, speciation, and mobility.


Contact Information

Douglas Kent
Bldg 15, McKelvey Building, 345 Middlefield Road
Menlo Park, CA 94025-3561
dbkent@usgs.gov
650-329-4461
650-329-4463 - Fax
Back to top

Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo USA.gov logo U.S. Department of the Interior | U.S. Geological Survey
URL: http://profile.usgs.gov/professional/mypage.php
Page Contact Information:Ask USGS
Page Last Modified: January 24 2013 17:21:51.
Version: 2.6