Igor Lehnherr, Assistant Professor


Home Campus:
U o f T Mississauga

University of Alberta (Environmental Biology and Ecology)

Other Degrees:
BSc., University of Victoria (Chemistry and Biology double major)

Contact Information:

Office: DV 3281 (UTM)
Phone: (905) 569-5769
Email: igor.lehnherr@utoronto.ca
(cross-appointed to the Institute of Management and Innovation)

Personal Website: http://sites.utm.utoronto.ca/lehnherr/

Research Interests:

  • Biogeochemistry of major and trace elements
  • Contaminants
  • Impacts of climate change on aquatic ecosystems
  • Arctic, boreal and alpine environments
  • Limnology and oceanography
  • Environmental chemistry

Teaching This Academic Year:

Geography Program:

GGR 227 – Ecosystems and Environmental Change

GGR 406 – Biogeochemistry

GGR 479 – Special Topics in Physical Geography: Contaminants in the Environment

GGR 1216 – Advanced Biogeochemical Processes (Graduate-level course)

MSc Sustainable Management Program:

SSM 1030 – Environmental Science

GGR 479 – Special Topics in Physical Geography: Contaminants in the Environment (approved science elective for MScSM students)

Current Students:


Selected Publications:

Refereed Articles

  1. Emmerton, C., V. St.Louis, I. Lehnherr, J. Graydon, J. Kirk and K. Rondeau. 2016. The net exchange of carbon greenhouse gases with freshwater systems in a High Arctic watershed. Biogeosciences, 13: 5849-5863 (Impact Factor (IF): 3.7, 5-Year IF: 4.5)
  2. Soerensen, A., D. Jacob, A. Schartup, J. Fisher, I. Lehnherr, V. St.Louis, L.-E. Heimburger, J. Sonke, E. Sunderland. 2016. A Mass Budget for Mercury and Methylmercury in the Arctic Ocean. Global Biogeochemical Cycles 30: 10.1002/2015GB005280 (IF: 4.5, 5-Year IF: 5.3).
  3. Pierre, K.A., V. St.Louis, J. Kirk, I. Lehnherr, S. Wang, C. La Farge. 2015. The importance of open marine waters to the enrichment of total mercury and monomethylmercury in lichens in the Canadian High Arctic. Environmental Science & Technology, 49: 5930-5938 (Featured on “Quirks & Quarks”, CBC Radio; IF: 5.4, 5-Year IF: 6.4).
  4. Steffen A., I. Lehnherr, A. Cole, P. Ariya, A. Dastoor, D. Durnford, J. Kirk, M. Pilote, Atmospheric Mercury in the Canadian Arctic. Part I: A review of recent field measurements. Science of the Total Environment, 509-510: 3-15 (IF: 3.2, 5-Year IF: 3.9).
  5. Braune, B. and 18 others, including I. Lehnherr. 2015. Mercury in the marine environment of the Canadian Arctic: A review of recent data. Science of the Total Environment, 509-510: 67-90.
  6. Chételat, J. and 22 others, including I. Lehnherr. 2015. Mercury in freshwater ecosystems of the Canadian Arctic: Recent advances on its cycling and fate. Science of the Total Environment, 509-510: 41-66.
  7. Dastoor A., A. Ryzhkov, D. Durnford, I. Lehnherr, A. Steffen. Atmospheric Mercury in the Canadian Arctic Part II: Insight from Modeling. Science of the Total Environment, 509-510: 16-27.
  8. Baya, P.A., M. Gosselin, I. Lehnherr, V.L. St. Louis and H. Hintelmann. 2015. Determination of monomethylmercury and dimethylmercury in the Arctic lower atmosphere. Environmental Science & Technology, 49: 223-232 (IF: 5.5, 5-Year IF: 6.3).
  9. Kirk, J.L., D.C.G. Muir, A. Gleason, X. Wang, R. Frank and I. Lehnherr. 2014. Atmospheric deposition of mercury and methylmercury to landscapes and waterbodies of the Athabasca Oil Sands Region. Environmental Science & Technology, 48: 7374-7383. (Selected as an American Chemical Society Editor’s Choice paper)
  10. Emmerton, C.A., V.L. St. Louis, I. Lehnherr, E.R. Humphreys, E. Rydz, and H. Kosolofski. 2014. Net exchange of methane with high Arctic landscapes during the summer growing season. Biogeosciences, 11: 3095-3106.
  11. Lehnherr, I. 2014. Methylmercury biogeochemistry: A review with special reference to Arctic aquatic ecosystems. Environmental Reviews, 22: 10.1139/er-2013-0059. (Selected by the journal as an “Editor’s Choice” paper, IF: 4.6, 5-yr IF: 4.3)
  12. Kirk, J. L., I. Lehnherr (co-lead author), M. Andersson, B. Braune, L. Chan, A. P. Dastoor, D. Durnford, A. L. Gleason, L. L. Loseto, A. Steffen, and V. L. St. Louis. 2012. Mercury in Arctic marine environments: sources, pathways and exposure. Environmental Research, 119: 64-87. (IF: 4.4, 5-yr IF: 4.2)
  13. Lehnherr, I., V. L. St. Louis, C. A. Emmerton, J. D. Barker and J. L. Kirk. 2012. Methylmercury cycling in high Arctic wetlands: sources and sinks. Environmental Science & Technology, 46: 10514-10522. (Featured on the journal cover)
  14. Lehnherr, I., J. L. Kirk and V. L. St. Louis. 2012. Methylmercury cycling in high Arctic wetlands: controls on sedimentary production. Environmental Science & Technology, 46: 10523-10531. (Featured on the journal cover)
  15. Lehnherr, I., V. L. St. Louis, H. Hintelmann and J. L. Kirk. 2011. Methylation of inorganic mercury in polar marine waters. Nature Geoscience, 4: 298-302. (Journal impact factor = 12.4)
  16. St. Louis, V. L., A. Derocher, I. Stirling, J. A. Graydon, C. Lee, E. Jocksch, E. Richardson, S. Ghorpade, A. K. Kwan, J. L. Kirk, I. Lehnherr and H. K. Swanson. 2011. Climate-induced changes in foodweb structure affecting mercury levels in Polar Bears (Ursus maritimus). Environmental Science & Technology, 45: 5922-5928.
  17. Mowat, L. D., V. L. St. Louis, J. A. Graydon, and I. Lehnherr. 2011. Influence of forest canopies on the deposition of methylmercury to boreal ecosystem watersheds. Environmental Science & Technology 45: 5178-5185.
  18. Lehnherr, I. and V. L. St. Louis. 2009. Importance of ultraviolet radiation in the photodemethylation of methylmercury in freshwater ecosystems. Environmental Science & Technology 43: 5692-5698.
  19. Graydon, J. A., V. L. St. Louis, H. Hintelmann, S. E. Lindberg, K. A. Sandilands, J. W. M. Rudd, C. A. Kelly, M. T. Tate, D. P. Krabbenhoft, and I. Lehnherr. 2009. Investigation of uptake and retention of atmospheric Hg(II) by boreal forest plants using stable Hg isotopes. Environmental Science & Technology 43: 4960-4966.
  20. Kirk, J. L., V. L. St. Louis, H. Hintelmann, I. Lehnherr, B. Else and L. Poissant. 2008. Methylated mercury species in marine waters of the Canadian high and sub Arctic. Environmental Science & Technology 42: 8367-8373.
  21. St. Louis, V. L., H. Hintelmann, J. A. Graydon, J. L. Kirk, J. Barker, B. Dimock, M. J. Sharp, and I. Lehnherr. 2007. Methylated mercury species in polar marine surface water and snowpacks. Environmental Science & Technology 41: 6433-6441.

Book Chapters

  1. Lehnherr, I. (lead author) and 17 others. Processes Contributing to the Net Production of Methylmercury in Canadian Freshwater Ecosystems. Ch. 6. In: Canadian Mercury Assessment Report, Ed. A. Steffen. Environment Canada, Clean Air Regulatory Agenda Mercury Science Program, in press.
  2. Chételat, J. and 22 others, including I. Lehnherr. Freshwater Environment. Ch. 5. In: Canadian Arctic Contaminants Assessment Report III: Mercury in Canada’s North. Eds. J. Chételat and B. Braune. Aboriginal Affairs and Northern Development Canada, Northern Contaminants Program, 2012.
  3. Chételat, J. and 19 others, including I. Lehnherr. Marine Environment. Ch. 6. In: Canadian Arctic Contaminants Assessment Report III: Mercury in Canada’s North. Eds. J. Chételat and B. Braune. Aboriginal Affairs and Northern Development Canada, Northern Contaminants Program, 2012.

Research Clusters:
Biogeochemistry and Contaminants, Climate Processes and Climate and Carbon Cycle Modelling, Earth-Surface Processes and Hydrology