Robert J. Letcher

Image Robert J. Letcher
Senior Research Scientist and Lab Head, Organic Contaminants Research Laboratory (OCRL)

Current research and/or projects

Contributes to EC’s objective of ensuring that wildlife and their ecosystems are conserved and protected, and general the health is assessed from a chemical exposure and stress standpoint

  • Analytical chemistry and method development, and  environmental and forensic chemistry of established (“legacy”) and emerging organic contaminants in wildlife and fish.
  • Bioaccumulation, fate and trophodynamics of established and emerging contaminants and metabolites in wildlife (e.g., top predators), food webs, and aquatic ecosystems (e.g., Arctic and Great Lakes).
  • Mechanistic and comparative biotransformation and pharmaco( toxico)kinetics of contaminants in wildlife and fish.
  • Species-specific, contaminant-mediated enzyme induction and associated contaminant metabolism and mechanisms.
  • Species- and ecosystem-specific ecotoxicology and effects of contaminant and metabolite exposure (e.g., endocrine disruption) and assessments.

Professional activities / interests

Associate (Carleton) Coordinator, Ottawa-Carleton Collaborative Chemical and Environmental Toxicology Program (2009 - present)

Workshop Co-organizer: 11th Workshop on Brominated Flame Retardants in the Environment (BFR’2009), May 19-20, Ottawa, ON, Canada

Editorial Board Member and Advisory Editor of the journals Environment International and Progress in Environmental Science

Board of Directors Member and Vice-President, International Association of Great lakes Research (IAGLR) (2009 - present)

Currently the direct thesis supervisor (via the Department of Chemistry, Carleton University) of 2 PhD and 1 MSc graduate students and 2 Postdoctoral Fellows; MSc thesis co-supervisor of 1 MSc student (Department of Biology, University of Windsor); thesis committee member of for various graduate students at the University of Ottawa and University of Guelph; Manager of 2 chemical techicians and 1 research mass spectrometrist (Envirnoment Canada, NWRC)

Research Grant Reviews

Canadian Foundation for Innovation (CFI), NSERC Discovery Grant selection committees, Postdoctoral Research Program (Health Canada), U.S. Environmental Protection Agency (EPA)

Scientific Journal Reviews

Journal of Toxicology and Environmental Heath, Analytical Chemistry, Environmental Science and Technology, Science of the Total Environment, Environmental Pollution, Toxicology In Vitro, Environmental Health Perspectives, Ambio, Archives of Environmental Contamination and Toxicology, Marine Environmental Research, Environmental Toxicology and Chemistry, Chemosphere

Education and awards

Post Doctoral Fellowships (1997-2000):

Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands

Toxicology Research Group, Wageningen Agricultural University, Wageningen, The Netherlands

Department of Marine Biogeochemistry & Toxicology, Netherlands Institute for Sea Research (NIOZ), Texel, The Netherlands

Key publications

Recent Publications, 2009-2010

Letcher, R.J., J.-O. Bustnes, R. Dietz, B.M. Jenssen, E.H. Jørgensen, C. Sonne, J. Verreault, M. Vijayan and G.W. Gabrielsen. 2010. Exposure and Effects assessment of persistent organic pollutants in Arctic wildlife and fish. Sci. Total Environ. 408(15): 2995-3043.

Routti, H., A. Arukwe, B.M. Jenssen, R.J. Letcher, M. Nyman, C. Bäckman and G.W. Gabrielsen. 2010. Comparative endocrine disruptive effects of contaminants in ringed seals (Phoca hispida) from Svalbard and the Baltic Sea. Comp. Biochem. Physiol. Part C. In press (available on-line June 1).

Montie, E.W., R.J. Letcher, C. Reddy, M. Moore, B. Rubinstein and M.E. Hahn. 2010. Organochlorine pesticides, polychlorinated biphenyls, and brominated flame retardants in marine vertebrates, including the endangered North Atlantic right whale, from the western Gulf of Maine. Mar. Pollut. Bull. (Baseline paper) (available on-line April 30).

Sonne, C., J. Verreault, G.W. Gabrielsen, R.J. Letcher, P.S. Leifsson and T. Iburg. 2010. Screening of thyroid gland histology in organohalogen-contaminated glaucous gulls (Larus hyperboreus) from the Norwegian Arctic. Toxicol. Environ. Chem. (short commun.) In press (April).

Marteinson, S.C., K.J. Fernie, J.L. Shutt, R.J. Letcher, J.I. Ritchie and D.M. Bird. 2010. Embryonic exposure of male American kestrels (Falco sparverius) to DE-71 flame retardant via maternal transfer reduces reproductive success and decreases courtship and brood-rearing behaviors. Environ. Toxicol. Chem. In press (available on-line April 13).

Letcher, R.J. 2010. Hexabromocyclododecane (HBCD) flame retardant in the environment, biota and humans: Sterioisomeric paradox. Toxicol. Lett. 196(Supp. 1, Abstracts of the XII International Congress of Toxicology): S33.

Kirkegaard, M., C. Sonne, R. Dietz, B.M. Jenssen, P.S. Leifsson, J.-E. Bech Jensen and R.J. Letcher. 2010. Testosterone concentrations and male genital organ morphology in Greenland sled dogs (Canis familiaris) dietary exposed to organohalogen contaminants. Toxicol. Environ. Chem. 92(5): 955-967.

Crump, D., C. Egloff, S. Chiu, R.J. Letcher, S.G. Chu and S.W. Kennedy. 2010. In ovo effects of exposure to technical hexabromocyclododecane (HBCD) on pipping success, hepatic mRNA expression and isomer-specific HBCD accumulation in embryos of white leghorn chickens (Gallus gallus domesticus). Toxicol. Sci. 115: 492-500.

Kirkegaard, M., C. Sonne, J. Jacobsen, R. Dietz, B.M. Jenssen, A.L. Jensen and R.J. Letcher. 2010. Organohalogens in a whale blubber supplemented diet affects hepatic retinol and renal tocopherol concentrations in Greenland sled dogs (Canis familiaris). J. Toxicol. Environ. Health Part A 73(12): 773-786.

Cesh, L.S., K.H. Elliott, S. Quade, M.A. McKinney, F. Maisonneuve, D.K. Garcelon, C.D. Sandau, R.J. Letcher, T.D. Williams and J.E. Elliott. 2010. Polyhalogenated aromatic hydrocarbons and metabolites: Relation to circulating thyroid hormone and retinol in nestling bald eagles (Haliaeetus leucocephalus). Environ. Toxicol. Chem. 29(6): 1301-1310.

Verboven, N., J. Verreault, R.J. Letcher, G.W. Gabrielsen and N.P. Evans. 2010. Adrenocortical function of Arctic-breeding glaucous gulls in relation to persistent organic pollutants. Gen. Comp. Endocrinol. 166(1): 25-32.

Gebbink, W.A. and R.J. Letcher. 2010. Linear and branched perfluorooctane sulfonate isomers and patterns in herring gull eggs from colonial sites across the Laurentian Great Lakes. Environ. Sci. Technol. 44: 3739–3745.

Fernie, K.J. and R.J. Letcher. 2010. Historical contaminants, flame retardants and halogenated phenolic compounds in peregrine falcon (Falco peregrinus) nestlings in the Canadian Great Lakes Basin. Environ. Sci. Technol. 44: 3520-3526.

Pilsner, J.R., A.L. Lazarus, D. Nam, R.J. Letcher, C. Sonne, R. Dietz and N. Basu. 2010. Mercury-associated DNA hypomethylation in polar bear brains via the luminometric methylation assay (LUMA): A sensitive method to study epigenetics in wildlife. Molecul. Ecol. 19: 301-314.

Ucán-Marín, F., A. Arukwe, A. Mortensen, G.W. Gabrielsen and R.J. Letcher. 2010. Recombinant albumin transport protein from gull species (Larus argentatus and hyperboreus) and human: Chlorinated and brominated contaminant binding and thyroid hormones. Environ. Sci. Technol. 44: 497-504.

de Solla, S.R., D.V. Weseloh, R.J. Letcher and C.E. Hebert. 2010. Reconcilable differences: The use of standard reference material to reduce methodological artifacts in the reporting of organochlorine pesticides and PCBs. Environ. Toxicol. Chem. 29: 19-26.

Sonne, C., K. Gustavson, F.F. Rigét, R. Dietz, M. Birkved, R.J. Letcher, R. Bossi, K. Vorkamp, E.W. Born and G. Petersen. 2009. Reproductive performance in East Greenland polar bears (Ursus maritimus) may be affected by organohalogen contaminants as shown by physiologically based pharmacokinetic (PBPK) modeling. Chemosphere 77: 1558-1568.

Gebbink, W.A., C.E. Hebert and R.J. Letcher. 2009. Perfluorinated carboxylates and sulfonates and precursor compounds in herring gull eggs from colonial sites spanning the Laurentian Great Lakes of North America. Environ. Sci. Technol. 43: 7443-7449.

Letcher, R.J. and S.G. Chu. 2009. Response to correspondence on linear and branched perfluorooctane sulfonate isomers in technical product and environmental samples by in-port derivatization-gas chromatography-mass spectrometry. Anal. Chem. 81(18): 7856-7857.

Letcher, R.J., W.A. Gebbink, C. Sonne, R. Dietz, M.A. McKinney and E.W. Born. 2009. Bioaccumulation and biotransformation of brominated and chlorinated contaminants and their Metabolites in ringed seals (Pusa hispida) and polar bears (Ursus maritimus) from East Greenland. Environ. Internat. 35: 1118-1124.

O’Brien, J.M., D. Crump, L.J. Mundy, S.G. Chu, K.K. McLaren, V. Vongpachan, R.J. Letcher and S.W. Kennedy. 2009. Pipping success and liver mRNA expression in chicken embryos exposed in ovo to C8 and C11 perfluorinated carboxylic acids and C10 perfluorinated sulfonates. Toxicol. Letters 190: 134-139.

Houde, M., G. Pacepavicius, C. Darling, P.A. Fair, M. Alaee, G.D. Bossart, K.R. Solomon, R.J. Letcher, Å. Bergman, G. Marsh and D.C.G. Muir. 2009. Polybrominated diphenyl ethers (PBDEs) and hydroxylated polybrominated diphenyl ethers (OH-PBDEs) in plasma of bottlenose dolphins (Tursiops truncatus) from the United States east coast. Environ. Toxicol. Chem. 28(10): 2061-2068.

Christensen, J.R., R.J. Letcher and P.S. Ross. 2009. Persistent or not persistent? Polychlorinated biphenyls readily depurated by grizzly bears. Environ. Toxicol. Chem. 28(10): 2206-2215.

Bennett, E.R., P.S. Ross, D. Huff, M. Alaee and R.J. Letcher. 2009. Polychlorinated and polybrominated compounds and metabolites in the plasma and diet of a captive killer whale (Orcinus orca). Mar. Pollut. Bull. (Baseline). 58: 1078-1083.

McKinney, M.A., E. Peacock and R.J. Letcher. 2009. Sea ice-associated diet change increases the levels of chlorinated and brominated contaminants in polar bears. Environ. Sci. Technol. 43: 4334-4339.

Henny, C.J., J.L. Kaiser, R.A. Grove, B.L. Johnson and R.J. Letcher. 2009. PBDE flame retardants in eggs may reduce reproductive success of ospreys in Oregon and Washington, USA. Ecotoxicol. 18: 802-813.

Routti, H., R.J. Letcher, B. van Bavel, A. Arukwe, S.-G. Chu and G.W. Gabrielsen. 2009. Polybrominated diphenyl ethers and their hydroxylated analogues in ringed seals (Phoca hispida) from Svalbard and the Baltic Sea. Environ. Sci. Technol. 43: 3494–3499.

Chu, S.G. and R.J. Letcher. 2009. Linear and branched perfluorooctane sulfonate isomers in technical product and environmental samples by in-port derivatization-gas chromatography-mass spectrometry. Anal. Chem. 81: 4256-4262.

Routti, H., B. van Bavel, R.J. Letcher, A. Arukwe, S.G. Chu and G.W. Gabrielsen. 2009. Concentrations, patterns and metabolites of organochlorine pesticides in relation to xenobiotic phase I and II enzyme activities in ringed seals (Phoca hispida) from Svalbard and the Baltic Sea. Environ. Pollut. 157: 2428-2434.

Montie, E.W., M.E. Hahn, C. Reddy, W.A. Gebbink, K.E. Touhey and R.J. Letcher. 2009. Organohalogen contaminants and metabolites in cerebrospinal fluid and cerebellum gray matter in short-beaked common dolphins and Atlantic white-sided dolphins from the western North Atlantic. Environ. Pollut. 157: 2345-2358.

Verreault, J., R.J. Letcher, C. Sonne and R. Dietz. 2009. In vitro metabolism of polychlorinated biphenyls and activity of xenobiotic-metabolizing enzymes in dietary-exposed sledge dogs in Greenland and model beagle dogs. Comp. Biochem. Physiol. Part C150: 91-100.

Hebert, C.E., D.V. Weseloh, L.T. Gauthier, M.T. Arts and R.J. Letcher. 2009. Ecological tracers reveal pathways of energy and nutrient transfer to seabirds. Oecologia. 160: 15-23.

Elliott, K.H., L.S. Cesh, J. Dooley, R.J. Letcher and J.E. Elliott. 2009. PCB and DDE, but not PBDEs, increase with trophic level and marine input in nestling bald eagles. Sci. Total Environ. 407: 3867-3875.

Fernie, K.J., J.L. Shutt, R.J. Letcher, J.I. Ritchie and D.M. Bird. 2009. Environmentally relevant concentrations of DE-71 and HBCD alter eggshell thickness and reproductive success of American kestrels. Environ. Sci. Technol. 43: 2124-2130.

Verboven, N., J. Verreault, R.J. Letcher, G.W. Gabrielsen and N. Evans. 2009. Differential investment in eggs by Arctic-breeding glaucous gulls exposed to persistent organic pollutants. The Auk. 126: 123-133.

O'Brien, J.M., A.C. Carew, S.G. Chu, R.J. Letcher and S.W. Kennedy. 2009. Perfluorooctane sulfonate (PFOS) toxicity in domestic chicken (Gallus gallus domesticus) embryos in the absence of effects on peroxisome proliferator activated receptor alpha (PPARα)-regulated genes Comp. Biochem. Physiol. Part C. 149: 524-530.

Verboven, N., J. Verreault, R.J. Letcher, G.W. Gabrielsen and N. Evans. 2009. Nest temperature and incubation behavior of arctic-breeding glaucous gulls exposed to persistent organic pollutants. Animal Behav. 77: 411-418.

Bechshøft, T.Ø., F.F. Rigét, C. Sonne, Ø. Wiig, R. Dietz and R.J. Letcher. 2009. Skull foramina asymmetry in East Greenland and Svalbard polar bears (Ursus maritimus) in relation to stressful environments. Ann. Zool. Fennici 46: 181–192.

Gauthier, L.T. and R.J. Letcher. 2009. Isomers of Dechlorane Plus flame retardant in the eggs of herring gulls (Larus argentatus) from the Laurentian Great Lakes of North America: Temporal changes and spatial distribution. Chemosphere. 75: 115-120.

Gauthier, L.T., D. Potter, C.E. Hebert and R.J. Letcher. 2009. Temporal changes and spatial distribution of non-polybrominated diphenyl ether flame retardants in the eggs of colonial populations of Great Lakes herring gulls. Environ. Sci. Technol. 43: 312-317.

Ucán-Marín, F., A. Arukwe, A. Mortensen, G.W. Gabrielsen, G.A. Fox and R.J. Letcher. 2009. Recombinant transthyretin purification and competitive binding with organohalogen compounds in two gull species (Larus argentatus and Larus hyperboreus). Toxicol. Sci. 107(2): 440-450.

Stapleton, H.M., S.M. Kelly, R. Pei, R.J. Letcher and C. Gunsch. 2009. Metabolism of polybrominated diphenyl ethers (PBDEs) by human hepatocytes in vitro. Environ. Health Perspect. 117: 197–202.

Basu, N., A.M. Scheuhammer, C. Sonne, R. Dietz and R.J. Letcher. 2009. Is mercury in the environment of neurotoxic concern to polar bears? Environ. Toxicol. Chem. 28: 133-140.

Verreault, J., F. Maisonneuve, R. Dietz, C. Sonne and R.J. Letcher. 2009. Comparative hepatic activities of major xenobiotic-metabolizing enzymes and circulating polychlorinated biphenyls and polybrominated diphenyl ethers and hydroxylated analogues in cohorts of captive Greenland sledge dogs. Environ. Toxicol. Chem. 28: 162-172.

Verreault, J., R.J. Letcher, C. Sonne and R. Dietz. 2009. Dietary, age and trans-generational effects on the fate of organohalogen contaminants in captive sledge dogs in Greenland. Environ. Internat. 35: 56-62.

Research facility

Carleton University, 1125 Colonel By Drive
Ottawa, ON K1A 0H3



Adjunct Professor, Department of Chemistry, Carleton University

Adjunct Professor, Great Lakes Institute for Environmental Research, University of Windsor

Associate Faculty, Department of Environmental Biology, University of Guelph



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