David Parkhurst

Biography

I have worked for the U.S. Geological Survey since high school. Before going to graduate school, I worked on calcite dissolution kinetics, sediment pore water chemistry, and geochemical modeling. I received a Master’s degree from Stanford University in 1985, and worked for the District Office in Oklahoma City on abandoned lead and zinc mines, the Roubidoux Aquifer, and a pilot NAWQA project. In 1989 I became chief of the Reactive-Transport Modeling project in Denver.  I develop geochemical reaction and transport models that can be used to investigate contaminant migration, acid mine drainage, nuclear waste disposal, and carbon sequestration.

 

Research Strategy

I use computer simulations to aid in understanding biogeochemical processes in contaminated and natural environments. The work blends the fields of chemistry, geology, biology, applied mathematics, and computer science to produce useful insights into real-world problems, including ore formation, acid-mine drainage, naturally occurring arsenic in groundwater, COsequestration, nuclear waste disposal, and aquifer storage recovery. The attempt is always to produce models that are easy to use, but capture as much of the physical and chemical processes as are necessary to obtain meaningful results.

Extended Biography

I was born in Washington, DC in 1952, and grew up in Alexandria, VA. I graduated from TC Williams High School as valedictorian in 1970, a couple years before “Remember the Titans”. As a high school student I volunteered for the U.S. Geological Survey (USGS), doing particle-size separations and running X-ray patterns on clay samples for Blair Jones and subsequently spent nearly my entire career with the USGS. I graduatedcum laude from Davidson College with a BS in mathematics in 1974, and continued to work for the USGS during college and following graduation. During these years I worked on calcite dissolution kinetics with Niel Plummer, sediment pore-water chemistry of the Potomac River Estuary with Ted Callender, and geochemical model development with Niel Plummer and Don Thorstenson. The geochemical model PHREEQE was published in 1980. I went to graduate school at Stanford University for a year and received an MS in Applied Earth Sciences in 1984 with a thesis on EXAFS (Extended X-ray Absorption Fine Structure) of zinc chloride solutions under George Parks and Gordon Brown. I then spent six years in Oklahoma working first on the Picher abandoned lead and zinc mining area , then hydrogeochemisty of the Roubidoux Aquifer, and the pilot National Water Quality Assessment project, which considered water-quality issues of the Garber-Wellington Aquifer, including contamination by organic compounds and naturally occurring arsenic. In 1989 I became chief of the Reactive-Transport Modeling project in Denver and focused on development of geochemical reaction and reaction-transport models, ultimately resulting in the PHREEQC and PHAST series of programs. Over the past decade, I have collaborated with field studies of nutrient transport from a sewage effluent plume on Cape Cod, Massachusetts, hydrogeochemistry of the Arbuckle-Simpson Aquifer in Oklahoma, and aquifer-storage-recovery projects in Kansas and South Carolina. I have taught numerous half-day to one week courses at universities and institutes in Europe and have been coordinator for the past 15 years for two geochemistry courses taught at the USGS. Most recently, I have been working on developing methods for high pressure geochemical calculations, a portable geochemical calculation module, graphical user interfaces for geochemical software, and, in general, extending geochemical modeling capabilities and simplifying the modeling process.

Work Experience

From: 1989 To: Present

Project Chief of Reaction-Transport Modeling in Ground-Water Systems

The principal objectives of the project are (1) to develop gener­al-use computer models that can identify and simulate geochemical and biological processes in flowing ground-water systems, and (2) to investigate geochemical processes and apply geochemical models in field studies. Fields of investigation for the project include development of the geochemical model PHREEQC, the reactive-transport model PHAST, and associated GUIs; development of WEBMOD, a watershed model that includes chemical reactions and isotopes; investigation of the climate history recorded in a calcite core from Devil's Hole Nevada; and measuring CO2 flux from desert soils in the Amargosa Desert.

From: 1986 To: 1989, Hydrologist, Oklahoma District, Oklahoma City

As geochemist on the Central Oklahoma aquifer NAWQA pilot project I helped design and implement a geochemical and geohydrologic investiga­tion of the aquifer and a regional sampling program for man-made organ­ic compounds and toxic trace elements.

From: 1983 To: 1986, Hydrologist, Oklahoma District, Oklahoma City

I was Project Chief in the Oklahoma District of a field study of aban­doned lead and zinc mines in the Picher Field of Oklahoma.

From: 1982 To: 1983, Student, Stanford University, Stanford, CA

Studied to obtain a master’s degree through the WRD graduate program including a thesis on EXAFS (extended x-ray absorption fine structure), mean-salt activity coefficients, and ion-association models.

From: 1977 To: 1982, Hydrologist, NRP, Reston, VA

I worked on Ted Callender’s project studying the geochemistry of the Potomac Estuary sediments. Responsibilities included supervising ship­board collection of sediment pore-water samples, data management, and developing diffusion and geochemical models.

From: 1976 To: 1977, Computer Programmer, FEMA, Charlottesville, VA

I programmed database reports for the Federal Emergency Management Agency.

From: 1975 To: 1976, Physical Science Technician, NRP, Reston, VA

I performed laboratory experiments on the dissolution kinetics of calcite on Niel Plummer’s NRP project and developed geochemical modeling pro­cedures.

From: 1969 To: 1974, Physical Science Technician, NRP, Reston, VA

Physical science technician on NRP projects in Rosslyn and Reston, Vir­ginia.

Education

Master of Science in Applied Earth Sciences, Stanford University, 1985

Bachelor of Science in Mathematics, Davidson College, 1974

Awards

John Hem Excellence in Science and Engineering Award, National Ground Water Association, 2002

Meritorious Service Award, U.S. Department of Interior, 2002

O.E. Meinzer Award, Hydrogeology Division of the Geological Society of America, 2012

 

Publications:

Charlton, S.R., and Parkhurst, D.L., 2012, Phast4Windows: A 3D graphical user interface for the reactive-transport simulator PHAST: Ground Water, in press.

Charlton, S.R., and Parkhurst, D.L., 2011, Modules based on the geochemical model PHREEQC for use in scripting and programming languages: Computers and Geosciences, vol. 37, no. 10, p. 1653-1663. http://dx.doi.org/10.1016/j.cageo.2011.02.005 [Link]

Müller, Mike, Parkhurst, D.L., Charlton, S.R., 2011, Programming PHREEQC calculations with C++ and Python, a comparative study: in Maxwell, R., Poeter, E., Hill, M.C., and Zheng, C., eds., MODFLOW and More 2011: Integrated Hydrologic Modeling Conference Proceedings, June 5–8, 2011, Golden, Colorado, p. 632–636.

Parkhurst, David L.; Kipp, Kenneth L.; Charlton, Scott R., 2010. PHAST Version 2-A Program for Simulating Groundwater Flow, Solute Transport, and Multicomponent Geochemical Reactions. U.S. Geological Survey Techniques and Methods 6-A35, xii, 235 p. [Link]

Cravotta, C.A., III, Parkhurst, D.L., Means, B., McKenzie, R., and Arthur, W., 2010, Using the computer program AMDTreat with a PHREEQC titration module to compute caustic quantity, effluent quality, and sludge volume: in Mine Water and Innovative Thinking, Wolkersdorfer, Christian, and Freund, Antje eds., International Mine Water Association 2010 Symposium, Sydney, Nova Scotia, Canada, p. 111-114. [Link]

Cravotta, C.A., III, Parkhurst, D.L., Means, B., McKenzie, R., Morris, H., and Arthur, W., 2010, A geochemical module for “AMDTreat” to compute caustic quantity, effluent quality, and sludge volume: in Bridging Reclamation, Science and Community, Barnhisel, R.I. ed., 2010 National Meeting of the American Society of Mining and Reclamation, June 5-11, 2010, Pittsburgh, PA, American Society of Mining and Reclamation, Lexington, Kentucky, p. 1413-1436. [Link]

Christenson, Scott; Hunt, Andrew G.; Parkhurst, David L.; Osborn, Noel I., 2009. Geochemistry of the Arbuckle-Simpson Aquifer. U.S. Geological Survey Fact Sheet 2009-3013, 4 p. [Link]

Christenson, Scott; Hunt, Andrew G.; Parkhurst, David L., 2009. Geochemical Investigation of the Arbuckle-Simpson Aquifer, South-Central Oklahoma, 2004-06. U.S. Geological Survey Scientific Investigations Report 2009-5036, vi, 51 p. [Link]

Yager, Richard M.; Misut, Paul E.; Langevin, Christian D.; Parkhurst, David L., 2009. Brine Migration from a Flooded Salt Mine in the Genesee Valley, Livingston County, New York: Geochemical Modeling and Simulation of Variable-Density Flow. U.S. Geological Survey Professional Paper 1767, Report: vii, 52 p.; Animations [Link]

Parkhurst, David L.; Charlton, Scott R., 2008. NetpathXL - An Excel Interface to the Program NETPATH. Geological Survey (U.S.) Techniques and Methods 6-A26, iii, 11 p. [Link]

Schmidt, Heather C. Ross; Ziegler, Andrew C.; Parkhurst, David L., 2007. Geochemical Effects of Induced Stream-Water and Artificial Recharge on the Equus Beds Aquifer, South-Central Kansas, 1995-2004. Geological Survey (U.S.) Scientific Investigations Report 2007-5025, vi, 59 p. [Link]

Christenson, Scott; Parkhurst, David; Hunt, Andrew G.; Athay, Denae, 2006. Age-dating ground water beneath Tinker Air Force Base, Midwest City, Oklahoma, 2003-04. Fact Sheet 2005-3099, 4 p. [Link]

Petkewich, Matthew D.; Parkhurst, David L.; Conlon, Kevin J.; Campbell, Bruce G.; Mirecki, June E., 2004. Hydrologic and Geochemical Evaluation of Aquifer Storage Recovery in the Santee Limestone/Black Mingo Aquifer, Charleston, South Carolina, 1998-2002. Scientific Investigations Report 2004-5046, 92 p. [Link]

Parkhurst, David L.; Kipp, Kenneth L.; Engesgaard, Peter; Charlton, Scott R., 2004. PHAST--a program for simulating ground-water flow, solute transport, and multicomponent geochemical reactions. Techniques and Methods 6-A8, 154 p. [Link]

Thorstenson, D.C., and Parkhurst, D.L., 2004, Calculation of individual isotope equilibrium constants for geochemical reactions: Geochimica et Cosmochimica Acta, v. 68, p. 2,449-2,465.

Parkhurst, D.L., 2004, PHREEQC—A computer program for geochemical calculations: International Ground Water Modeling Center Newsletter, Colorado School of Mines, v. 22, no. 2, p. 2.

Parkhurst, David L.; Stollenwerk, Kenneth G.; Colman, John A., 2003. Reactive-transport simulation of phosphorus in the sewage plume at the Massachusetts Military Reservation, Cape Cod, Massachusetts. Water-Resources Investigations Report 2003-4017, v, 33 p. : ill., col. maps ; 28 cm. [Link]

Thorstenson, Donald C.; Parkhurst, David L., 2002. Calculation of individual isotope equilibrium constants for implementation in geochemical models. Water-Resources Investigations Report 2002-4172, iv, 129 p. ; 28 cm.[Link]

Charlton, S. R.; Parkhurst, D. L., 2002. PHREEQCI -- A Graphical User Interface to the Geochemical Model PHREEQC. Fact Sheet 031-02, 2 p. [Link]

Parkhurst, D.L., and Petkewich, M.D., 2002, Geochemical modeling of an aquifer storage recovery experiment, Charleston, South Carolina, in U.S. Geological Survey Artificial Recharge Workshop Proceedings, Sacramento, California, April 2-4, 2002, G. Aiken, ed.: U.S. Geological Survey Open-File Report 02-89, pp. 37-40.

Parkhurst, D.L., and Kipp, K.L., 2002, Parallel processing for PHAST--A three-dimensional reactive-transport simulator, in Hassanizadeh, S.M., Schlotting, R.J., Gray, W.H., and Pinder, G.F., eds., Computational methods in water resources, v.2, Develeopments in water science, n. 47, Amsterdam, The Netherlands, Elsevier, p. 711-718.

Parkhurst, D.L., Thorstenson, D.C., and Kipp, K.L., 2000, Calculating carbon-isotope compositions in an unsaturated zone with seasonally varying CO2 production: in Wang, Yanxin, ed., Proceedings of the International Symposium on Hydrogeology and the Environment: October 17-21, 2000, Wuhan, P.R. China, p. 220-224.

Parkhurst, David L.; Appelo, C. A. J., 1999. User's guide to PHREEQC (Version 2) : a computer program for speciation, batch-reaction, one-dimensional transport, and inverse geochemical calculations. U.S. Geological Survey : Earth Science Information Center, Open-File Reports Section [distributor], Water-Resources Investigations Report 99-4259, xiv, 312 p. :ill. ;28 cm.

Christenson, Scott, Parkhurst, D.L., and Breit, G.N., 1998, Summary of geochemical and geohydrologic investigations of the Central Oklahoma aquifer, in Christenson, Scott., and Havens, J.S., eds., Ground-water quality assessment of the Central Oklahoma aquifer, Oklahoma: Results of investigations: Water Supply Paper 2357A, p. 107-117.

Charlton, Scott R.; Macklin, Clifford L.; Parkhurst, David L., 1997. PHREEQCI; a graphical user interface for the geochemical computer program PHREEQC. U.S. Geological Survey ; Branch of Information Services, [distributor], Water-Resources Investigations Report 97-4222, 9 p.

Christenson, Scott, Parkhurst, D.L., and Breit, G.N., 1997, Summary of geochemical and geohydrologic investigations of the Central Oklahoma aquifer, in Christenson, Scott., and Havens, J.S., eds., Ground-water quality assessment of the Central Oklahoma aquifer, Oklahoma: Results of investigations: Water Resources Investigations Report 97-4186, p. 107-117.

Parkhurst, D.L., 1997, Geochemical mole-balance modeling with uncertain data: Water Resources Research, v. 33, no. 8, p. 1957-1970.

Parkhurst, David L.; Christenson, Scott C.; Breit, George N. , 1996. Ground-water-quality assessment of the central Oklahoma Aquifer, Oklahoma; geochemical and geohydrologic investigations. U.S. G.P.O. ; For sale by U.S. Geological Survey, Information Services, Water Supply Paper 2357-C, ix, 101 p. :ill., maps (some col.) ;28 cm.

Parkhurst, D. L., 1995. User's guide to PHREEQC, a computer program for speciation, reaction-path, advective-transport, and inverse geochemical calculations. U.S. Geological Survey ; U.S. Geological Survey, Earth Science Information Center, Open-File Reports Section [distributor], Water-Resources Investigations Report 95-4227, viii, 143 p. :ill. ;28 cm.

Plummer, L. Niel; Prestemon, Eric C.; Parkhurst, David L., 1994. An interactive code (NETPATH) for modeling NET geochemical reactions along a flow PATH, version 2.0. U.S. Geological Survey ;USGS Earth Science Information Center, Open-File Reports Section [distributor], Water-Resources Investigations Report 94-4169, iv, 130 p. ;28 cm.

Parkhurst, David L.; Christenson, Scott C.; Schlottmann, Jamie L. , 1994. Ground-water-quality assessment of the Central Oklahoma Aquifer, Oklahoma; analysis of available water-quality data through 1987. U.S. G.P.O., Water Supply Paper 2357-B, viii, 74 p. :ill., maps ;28 cm.

Christenson, S.C., Parkhurst, D.L., and Fairchild, R.W., 1994, Geohydrology and water quality of the Roubidoux Aquifer, northeastern Oklahoma: Oklahoma Geological Survey Circular 96, 70 p.

Parkhurst, D. L.; Christenson, S. C.; Breit, G. N., 1993. Ground-water-quality assessment of the Central Oklahoma Aquifer, Oklahoma; geochemical and geohydrologic investigations. U.S. Geological Survey ; Books and Open-File Reports Section [distributor], Open-File Report 92-642, viii, 113 p. :ill., maps ;28 cm.

Glynn, P.D., and Parkhurst, D.L., 1992, Modeling non-ideal solid-solution aqueous-solution reactions in mass-transfer computer codes, in Kharaka, Y.K., and Maest, A.S., eds., Water- Rock Interaction 7: Rotterdam, Balkema, p. 175-179.

Parkhurst, D.L., 1992, The geochemical evolution of ground waters in the Central Oklahoma aquifer, inChristenson, Scott, and Carpenter, Lyn, eds., Ground-water quality of the Central Oklahoma (Garber-Wellington) aquifer conference: Proceedings, February 20, 1992: U.S. Geological Survey Open-File Report 92-116, p. 7-9.

Plummer, L.N., Prestemon, E.C., and Parkhurst, D.L., 1992, NETPATH—an interactive code for interpreting NET geochemical reactions from chemical and isotopic data along a flow PATH, in Kharaka, Y.K., and Maest, A.S., eds., Water-Rock Interaction 7: Rotterdam, Balkema, p. 239-242.

Plummer, L. N.; Prestemon, E. C.; Parkhurst, D. L., 1991. An interactive code (NETPATH) for modeling NET geochemical reactions along a flow PATH. U.S. Geological Survey ; Books and Open-File Reports Section, Water-Resources Investigations Report 91-4078, iv, 227 p. ;28 cm. +1 computer disk (5 1/4 in.)

Christenson, S. C.; Parkhurst, D. L.; Fairchild, R. W., 1990. Geohydrology and water quality of the Roubidoux Aquifer, northeastern Oklahoma. U.S. Geological Survey ; Books and Open-File Report Section [distributor], Open-File Report 90-570, vi, 110 p. :ill., maps ;28 cm.

Nordstrom, D.K., Plummer, L.N., Langmuir, Donald, Busenberg, Eurybiades, May, H.M., Jones, B.F., and Parkhurst, D.L., 1990, Revised chemical equilibrium data for major water-mineral reactions and their limitations in Bassett, R.L. and Melchior, D. eds., Chemical modeling in aqueous systems II: Washington D.C., American Chemical Society Symposium Series 416., chap. 31, p. 398-413.

Parkhurst, D.L., 1990, Ion-association models and mean-activity coefficients of various salts, in Bassett, R.L. and Melchior, D. eds., Chemical modeling in aqueous systems II: Washington D.C., American Chemical Society Symposium Series 416. chap. 3, p. 30-43.

Plummer, L.N. and Parkhurst, D.L., 1990, Application of the Pitzer equations to the PHREEQE geochemical model in Bassett, R.L. and Melchior, D. eds., Chemical modeling in aqueous systems II: Washington D.C., American Chemical Society Symposium Series 416, chap. 10, p. 128-137.

Parkhurst, D. L.; Christenson, S. C.; Schlottmann, J. L., 1989. Ground-water quality assessment of the central Oklahoma aquifer, Oklahoma; analysis of available water-quality data through 1987. U.S. Geological Survey ; Books and Open-File Report Section [distributor], Open-File Report 88-728, viii, 80 p. :ill. ;28 cm.

Plummer, L. N.; Parkhurst, D. L.; Fleming, G. W.; Dunkle, S. A., 1988. A computer program incorporating Pitzer's equations for calculation of geochemical reactions in brines. U.S. Geological Survey, Water-Resources Investigations Report 88-4153, vi, 310 p. :ill. ;28 cm.

Parkhurst, David L.; Doughten, Michael; Hearn, Paul P., Jr., 1988. Chemical analyses of stream sediment in the Tar Creek basin of the Picher mining area, northeast Oklahoma. U.S. Geological Survey, Open-File Report 88-469, iii, 13 p. : ill., maps ;28 cm. [Link]

Parkhurst, D.L., 1988, Mine-water discharge, metal loading, and chemical reactions, in Ragone, S.E. ed., U.S. Geological Survey Program on Toxic Waste -- Ground-Water Contamination: Proceedings of the second technical meeting, Cape Cod, Massachusetts, October 21-25, 1985: U.S. Geological Survey Open-File Report 86-481, p. D5-D10.

Parkhurst, David L. , 1987. Chemical analyses of water samples from the Picher mining area, northeast Oklahoma and southeast Kansas. U.S. Geological Survey, Open-File Report 87-453, iv, 43 p. :ill., maps ;28 cm.[Link]

Christenson, S.C., and Parkhurst, D.L., 1987, Ground-water quality assessment of the central Oklahoma aquifer, Oklahoma - project description: U.S. Geological Survey Open-File Report 87-235, 30 p.

Parkhurst, D.L., 1985, The application of EXAFS and mean activity coefficient data to ion- association models for the zinc-chloride system: Thesis, Stanford University, 71 p.

Muller, A.B., Parkhurst, D.L., and Tasker, P.W., 1986, The use of the PHREEQE code in modelling environmental geochemical problems encountered in performance assessment modelling, in Symposium on Ground-water Flow and Transport Modelling for Performance Assessment of Deep Geologic Disposal of Radioactive Waste--A Critical Evaluation of the State of the Art: Sponsored by U.S. Department of Energy, Civilian Waste Management, May 20-21, 1985, Albuquerque, New Mexico.

Goodwin, S. D.; Schultz, B. I.; Parkhurst, D. L.; Simon, N. S.; Callendar, Edward , 1984. Methods for the collection of geochemical data from the sediments of the tidal Potomac River and estuary and data for 1978-1980. U.S. Geological Survey, Open-File Report 84-74, iii, 156 p. 8 cm.

Hearn, P.P., Parkhurst, D.L., and Callender, Edward, 1983, Authigenic vivianite in Potomac River sediments--Control by ferric oxy-hydroxides: Journal of Sedimentary Petrology, v. 53, p. 165-177.

Plummer, L.N., Parkhurst, D.L., and Thorstenson, D.C., 1983, Development of reaction models in ground-water systems: Geochimica et Cosmochimica Acta, v. 47, p. 665-686.

Parkhurst, David L.; Plummer, L. Niel; Thorstenson, Donald C., 1982. BALANCE : a computer program for calculating mass transfer for geochemical reactions in ground water. U.S. Geological Survey, Water-Resources Investigations Report 82-14, iii, 29 p. ;28 cm.

Parkhurst, David L.; Thorstenson, Donald C.; Plummer, L. Niel, 1980. PHREEQE : a computer program for geochemical calculations. U.S. Geological Survey, Water Resources Division, Water-Resources Investigations Report 80-96, v, 210 p. :ill. ;28 cm.

Parkhurst, D.L., and Callender, Edward, 1979, Geochemistry of sediments and associated- interstitial waters for the tidal Potomac River: in Bennett, J.P., ed., Seminar on Water Quality in the Tidal Potomac River, December 1978: U.S. Geological Survey Open-File Report 79-1588.

Plummer, L.N., Wigley, T.M.L., and Parkhurst, D.L., 1979, Critical review of the kinetics of calcite dissolution and precipitation, in Jenne, E.A., ed., Chemical modeling in aqueous systems-- Speciation, sorption, solubility, and kinetics: American Chemical Society Symposium Series, No. 93, p. 537-573.

Plummer, L.N., Wigley, T.M.L., and Parkhurst, D.L., 1978, The kinetics of calcite dissolution in CO2-water systems at 5 to 60 C and 0.0 to 1.0 atm CO2: American Journal of Science 278, p. 179-216.

Plummer, L. Niel; Parkhurst, David L.; Kosiur, David R., 1975. MIX2 : a computer program for modeling chemical reaction in natural waters. U.S. Geological Survey, Water Resources Division, Water-Resources Investigations Report 75-61, iii, 68 leaves ;27 cm.