Publications and Funding


Recent Publications

Bopp, CJ (IV), Lundstrom, CC, Johnson, TM, Sanford, R, Long, P. and Williams, K (in review) Uranium Isotope Ratios as Indicators of Reduction: Results from an in situ Biostimulation Experiment at Rifle, CO, Environmental Science and Technology, submitted.

Clark, S.K. and Johnson, T.M. (accepted pending light revisions) Selenium Stable Isotope Investigation Into Selenium Biogeochemical Cycling In A Lacustrine Environment: Sweitzer Lake, CO, Journal of Environmental Quality.

Berna, E.C., Johnson, T.M., Makdisi, R.S. and Basui, A. (2010). Cr Stable Isotopes As Indicators of Cr(VI) Reduction in Groundwater: A Detailed Time-Series Study of a Point-Source Plume. Environmental Science & Technology, 44(3): 1043-1048. DOI:10.1021/Es902280s


Mead, C. and Johnson, T.M. (2010) Hg stable isotope analysis by the double-spike method. Anal. Bioanal. Chem., in press.


Bopp, CJ (IV), Craig C. Lundstrom, Thomas M. Johnson, and Justin J. G. Glessner , 2009.
Variations in 238 U/ 235 U in uranium ore deposits; isotopic signatures of the U reduction process?
Geology  37(7):611-614. DOI: 10.1130/G25550A.1

Bethke, C.M. and Johnson, T.M., 2008. Groundwater Age and Groundwater Age Dating. Ann. Rev. Earth Planet. Sci., 36: 121-152.


Clark, S.K. and Johnson, T.M., 2008. Effective isotopic fractionation factors for solute removal by reactive sediments: A laboratory microcosm and slurry study. Environ. Sci. Technol., 42(21): 7850-7855.


Hedman, K.M., Curry, B.B., Johnson, T.M., Fullagar, P.D. and Emerson, T.E., 2008. Variation in strontium isotope ratios of archaeological fauna in theMidwestern United States: A preliminary study J. Archaeolog. Sci., 36: 64-73.


Sikora, E.R., Johnson, T.M. and Bullen, T.D., 2008. Microbial mass-dependent fractionation of chromium isotopes. Geochim. Cosmochim. Acta, 72: 3631–3641.


Mehnert E., Hwang H.-H., Johnson T. M., Sanford R. A., Beaumont W. C., and Holm T. R. (2007) Denitrification in the shallow ground water of a tile-drained, agricultural watershed. J. Environ. Qual. 36, 80-90

Rademacher, L. K., Lundstrom, C. C., Johnson, T.M., Sanford, R. A., Zhao, J., and Zhang, Z.  (2006) Experimentally Determined Uranium Isotope Fractionation During Reduction of Hexavalent U by Bacteria and Zero Valent Iron.  Env. Sci. Technol., 40, 6943-6948.

Johnson, T.M. and Bullen, T.D. (2004). Mass-dependent fractionation of selenium and chromium isotopes in low-temperature environments. In: C.M. Johnson, B.L. Beard and F. Albarede (Editors), Geochemistry of Non-Traditional Stable Isotopes. Rev. Mineral. 55, Mineral. Soc. Amer., Washington, D.C., 289-317.

Johnson, T. M. and Bullen, T. D. (2004) Selenium, Iron and Chromium Stable Isotope Ratio Measurements by the Double Isotope Spike TIMS Method, in , P. DeGroot, ed., Handbook of Stable Isotope Analytical Techniques, Ch. 29, pp. 632-651, Elsevier, Amsterdam.

Ellis A. S1., Johnson T. M., and Bullen T. D. (2004) Using Chromium Stable Isotope Ratios to Quantify Cr(VI) reduction: Lack of Sorption Effects. Env. Sci. Technol., 38, 3604-3607.

Johnson, T.M. (2004) A review of mass-dependent fractionation of selenium isotopes and implications for other heavy stable isotopes. Chemical Geology, in press.

Johnson T. M. and Bullen T. D. (2003) Selenium isotope fractionation during reduction of Se oxyanions by Fe(II) + Fe(III) hydroxide-sulfate (green rust), Geochimica et Cosmochimica Acta, 67, 413-419.  http://www.elsevier.nl/locate/gca   (doi:10.1016/S0016-7037(02)01137-7)

Ellis A. S., Johnson T. M., Bullen T. D., and Herbel M. J. (2003) Selenium isotope fractionation by natural microbial consortia in unamended sediment slurries. in press, Chem. Geol. 195, 119-129. http://www.elsevier.com/locate/issn/00092541

Ellis A. S., Johnson T. M., and Bullen T. D., (2002) Cr isotopes ratios and the fate of Cr in the environment. Science, 295, 2060-2062.   http://dx.doi.org/10.1126/science.1068368

Bethke, C.M., and Johnson, T.M., (2002) Ground water age. Ground Water, 40, 337-339.

Herbel, M.J., Johnson, T.M., Tanji, K. K., Gao, S., and Bullen, T.D. (2002) Selenium stable isotope ratios in California agricultural drainage water, J. Environ. Qual. 31(4), 1146-1156. http://jeq.scijournals.org/cgi/content/full/31/4/1146

Bethke, C. M., and Johnson T. M., (2002) Paradox of groundwater age, Geology, 30, 107-110.

McLing, T. L., Smith, R. W., and Johnson, T.M., (2001) Chemical characteristics of thermal water beneath the eastern Snake River Plain aquifer, in L.L. Mink and P. K. Link, eds., Geology, hydrogeology, and environmental remediation: Idaho National Engineering and Environmental Laboratory, Eastern Snake River Plain, Idaho, Geological Society of America Special Paper 353, 205-212.

Roback R. C., Johnson T. M., McLing T. L., Murrell M. T., Luo, S. and Ku, T.-L. (2001) Uranium isotopic evidence for groundwater chemical evolution and flow patterns in the eastern Snake River Plain aquifer, Idaho, Geol. Soc. Amer. Bull., 113, 1133-1141.

Johnson T. M., Roback R. C., McLing T. L., Bullen T. D., DePaolo D. J., Doughty C., Hunt R. J., Murrell M. T., and Smith R. W. (2000) Groundwater 'Fast Paths' in the Snake River Plain Aquifer: Radiogenic Isotope Ratios as Natural Groundwater Tracers, Geology, 28, 871-874. http://www.gsajournals.org/gsaonline/?request=get-pdf&file=i0091-7613-028-10-0871.pdf

Herbel, M.J., Johnson, T.M., Oremland, R.S., Bullen, T.D. (2000) Fractionation of Selenium Isotopes during Bacterial Respiratory Reduction of Selenium Oxyanions, Geochim. Cosmochim. Acta,, 64, 3701-3709. http://www.elsevier.com/locate/issn/00167037

Johnson, T. M., Bullen, T. D., and P. T. Zawislanski (2000) Selenium stable isotope ratios as indicators of sources and cycling of selenium: Results from the northern reach of San Francisco Bay, Env. Sci. Technol.,34, 2075-2079. http://pubs3.acs.org/acs/journals/doilookup?in_doi=10.1021/es990187y

Johnson, T.M., Herbel, M.J., Bullen, T.D., and Zawislanski, P.T. (1999) Se isotope ratios as indicators of Se sources and oxyanion reduction, Geochim. Cosmochim. Acta, 63, 2775-2784. http://www.elsevier.com/locate/issn/00167037

Johnson, T.M. and DePaolo, D.J., (1997) Rapid exchange effects on isotope ratios in groundwater systems, 1, Development of a transport-dissolution-exchange model. Water Resour. Res. 33, 187-196.

Johnson, T.M. and DePaolo, D.J., (1997) Rapid exchange effects on isotope ratios in groundwater systems, 2, Flow investigation using Sr isotope ratios. Water Resour. Res. 33, 197-210.

Johnson, T.M. and DePaolo, D.J., (1996) Reaction-transport models for radiocarbon in groundwater: The effects of dispersive transport and the use of Sr isotope ratios to correct for water-rock interaction. Water Resour. Res. 32, 2203-2212.

Johnson, T.M. and DePaolo, D.J., (1994) Interpretation of isotopic data in groundwater systems: Model development and application to Sr isotope data from Yucca Mountain. Water Resour. Res. 30, 1571-1587.


Funded Grants

Exploratory Research: Mercury Stable Isotopes as Indicators of the Biogeochemical Cycling of Mercury. Thomas M. Johnson, P.I., 4/2010 to 4/2011, $120,505, US Dept. of Energy ERSP Program.

MURMoT: Design and Application of Microbial Uranium Reduction Monitoring Tools. Robert Sanford, Craig Lundstrom and Thomas Johnson, co-PI’s, 10/2009 to 10/2012, US Dept. of Energy ERSP Program.

Geochemical and Isotope Characterization of TVA Coal Combustion Products: Identification of contaminants and modeling their fate in the environment, Avner Vengosh (lead PI); Co-PIs: Heileen Hsu-Kim, Jim Hower, Thomas M. Johnson. 4/2010-4/2013. Illinois component is $20,000 out of $357,000 total.

Collaborative Research:  Chromium isotopes as redox indicators - Oxidation and isotopic equilibration experiments.  9/2009 to 8/2011, $163,513 to Illinois, NSF Geobiology and Low Temperature Geochemistry.

Chromium Isotopes As Indicators Of Hexavalent Chromium Reduction, Thomas M. Johnson, P.I., 4/2007 to 4/2010, $301,177, US Dept. of Energy ERSP Program.

Technical support for the new MC-ICP-MS laboratory at UIUC, Craig C. Lundstrom and Thomas M. Johnson, cp-PI’s, 8/15/04 to 8/14/07, $225,000, NSF Geoscience Instrumentation and Facilities.

Acquisition of a multicollector inductively coupled plasma mass spectrometer, Craig C. Lundstrom and Thomas M. Johnson, co-PI’s, 8/1/03 to 7/30/04, $493,640, NSF Major Research Instrumentation program.


Quantification of hexavalent Cr reduction in groundwater using Cr stable isotopes. Thomas M. Johnson (P.I.) NSF Hydrologic Sciences Program, 1/1/03 to 12/30/06, $207,292.

Field investigation of Se oxyanion reduction and Se sources in wetlands: Application of Se isotopes. Thomas M. Johnson (P.I.), and Thomas D. Bullen, NSF Hydrologic Sciences Program, 1/1/01 to 12/30/03, $232,239.

Estimation of denitrification rates in the shallow groundwater flow system of Big Ditch Watershed, Illinois, Illinois Council for Food and Agricultural Research, Thomas M. Johnson (P.I.), E. Mehnert and Hue-Hwa Hwang (Illinois State Geological Survey), T. Holm (Illinois State Water Survey), and Robert Sanford (UIUC Environmental Engineering) , 1/1/00 to 12/30/03, $176,000 ($39,760 to Johnson).

Development of selenium isotope ratios as indicators of sedimentary paleo-environments, Thomas M. Johnson (P.I.), America Chemical Society/ Petroleum Research Fund, 7/1/00 to 6/30/03, $25,000.

Development of Cr stable isotopes for Cr transport studies and other geoscience applications, Thomas M. Johnson (P.I.), NSF Hydrologic Sciences Program. 6/1/2000 to 4/1/2002, $58,219.

Selenium Stable Isotope Ratios as Indicators of Selenium Transport and Cycling. Thomas M. Johnson (P.I.), and Thomas Bullen (U.S. Geological Survey), NSF Hydrologic Sciences Program, 4/15/98 to 4/14/2000. $200,000 ($158,504 to Johnson; Bullen provided mass spectrometry facilities)

Investigation of Groundwater Flow Paths Through Combined Inversion of Strontium Isotope Ratios and Hydraulic Head Data. Thomas M. Johnson (P.I.), C.M. Doughty, J. Long. and D. DePaolo (Lawrence Berkeley National Laboratory) and R. Smith (Idaho National Engineering Laboratory), U. S. Dept. of Energy ER/EM Collaborative Research Program, 4/1/97 to 9/30/99. $473,400 ($138,244 to Johnson; shared leadership of project with Doughty).