Karen Kidd, Ph.D. Stephen A. Jarislowsky Chair in Environment and Health

Telephone: (905) 525-9140

Office: LSB-337 Ext 23550

Lab: LSB – 304

Email: karenkidd@mcmaster.ca  

Interests & Activities

The main focus of our research is on understanding the effects of human activities – food production, natural resource extraction, urban environments – on the health of freshwater and marine ecosystems. Our field studies assess how industrial, agricultural, aquacultural and municipal effluents and runoff affect the diversity, abundance and health of aquatic organisms and the structure of food webs, and why fish and other aquatic life from some areas are higher in contaminants than others. Much of our current work is on the fate and effects of mercury – a pollutant of global concern – in diverse species and environments including Chile, Antarctica, northern Ontario, Atlantic Canada, the Canadian Arctic, Mexico and Norway.

We are also assessing the effects of forest management and agriculture on water quality, invertebrate biodiversity, fish communities, and food web structure in streams in New Brunswick and Ontario, the accumulation of nutrients and metals in lobster and other organisms near salmon aquaculture sites in the Bay of Fundy, the potential impacts of dam removal on contaminant fate and food webs in the Saint John River, and how contaminants in municipal wastewaters affect downstream organisms.


Peer-reviewed journal articles (students in my lab are underlined)


Cowie, A.M., K.I. Sarty, A. Mercer, J. Koh, K. A. Kidd, and C.J. Martyniuk. 2017. Transcriptomic and proteomic analysis implicates mitochondria and the immune system as molecular targets of dieldrin in the zebrafish (Danio rerio) central nervous system. J. Proteomics. 157:71-82.

Wellman, S., K.A. Kidd, C.L. Podemski, P.J. Blanchfield, and M.J. Paterson. 2017. Incorporation of wastes by native biota during and after an experimental aquaculture operation. Fresh. Sci. 36(2): 387-401.

Lescord, G.L., M.G. Clayden, K.A. Kidd, X. Wang, D.C.G. Muir, and N.J. O’Driscoll. 2017. Using sulfur stable isotopes to assess mercury bioaccumulation and biomagnification in biota in temperate lake food webs. Environ. Toxicol. Chem. 36(3):661-670.

Graves, S.D., K.A. Kidd, K.L. Batchelar, A. Cowie, N.J. O’Driscoll, and C.J. Martyniuk. 2017. Transcript responses for oxidative stress in the brain of wild yellow perch (Perca flavescens) exposed to a gradient of methylmercury in Kejimkujik National Park, Canada. Comparative Biochemistry and Physiology: part C. 192:50-58.

Graves, S.D., K.A. Kidd, J.E. Houlahan, K.R.  Munkittrick. 2017. General and histological indicators of health in wild fishes from a biological mercury hotspot in northeastern North America. Environ. Toxicol. Chem. 36(4):976-987.


Aguilar-Betancourt, C.M., G. González-Sansón, K.A. Kidd, K.R. Munkittrick, R.A. Curry, D. Kosonoy-Aceves, G. Lucano-Ramírez, S. Ruiz-Ramírez and J. R. Flores-Ortega. 2016. Fishes as indicators of untreated sewage contamination in a Mexican coastal lagoon. Mar. Poll. Bull. 113(1):100-109.

Zoeller, R.T., A. Bergman, G. Becher, P. Bjerregaard, R. Bowman, I. Brandt, T. Iguchi, S. Jobling, K.A., Kidd, A. Kortenkamp, N. Skakkebaek, J. Toppari, and L. Vandenberg. The path forward on endocrine disruptors requires focus on the basics. Toxicol. Sci. 149(2):272-272.

Vandenberg, L.N., M. Ågerstrand, A. Beronius, C. Beausoleil, Å. Bergman, L.A. Bero, C.-G. Bornehag, C.S. Boyer, G.S. Cooper, I. Cotgreave, D. Geek, P. Grandjean, K.Z. Guyton, U. Hass, J.J. Heindel, S. Jobling, K.A. Kidd, A. Kortenkamp, M.R. Macleod, O.V. Martin, U. Norinder, M. Scheringer, K.A. Thayer, J. Toppari, P. Whaley, T.J. Woodruff, C. Rudén. 2016. A proposed framework for the systematic review and integrated assessment (SYRINA) of endocrine disrupting chemicals. Environmental Health. 15: 74-93.

Finley, M.L., K.A. Kidd, R.A. Curry, G.L. Lescord, M.G. Clayden, and N.J. O’Driscoll. 2016. A comparison of mercury biomagnification through lacustrine food webs supporting brook trout and other fishes. Frontiers in Environmental Science, 4(23): 1-13.

Walters, D.M., T.D. Jardine, B.S. Cade, K.A. Kidd, D.C.G. Muir, and P. Leipzig-Scott. 2016. Trophic magnification of organic chemicals – a global synthesis. Environ. Sci. Technol. 50 (9): 4650–4658.

Baker, L.F., Mudge, J.F., Thompson, D.G., Houlahan, J.E., and K.A. Kidd. 2016. The combined influence of two agricultural contaminants of natural communities of phytoplankton and zooplankton. Ecotoxicology 25(5): 1021-1032.

Pippy, B.A., K.A. Kidd, K.R. Munkittrick, A. Mercer, and H. Hunt. 2016. Use of Nucula proxima and Nephtys incisa in a sentinel species approach for monitoring the health of Bay of Fundy estuaries. Mar. Poll. Bull. 106(1-2):225-235.


Bergman, A., G. Becher, B. Blumberg, P. Bjerregaard, R. Bornman, I. Brandt, S.C. Casey, H. Frouin, L.C. Giudice, J.J. Heindel, T. Iguchi, S. Jobling, K.A. Kidd, A. Kortenkamp, P.M. Lind, D. Muir, R. Ochieng, E. Ropstad, P. S. Ross, N.E. Skakkebaek, J. Toppari, L.N. Vandenberg, T.J. Woodruff, R.T. Zoeller. 2015. Manufacturing doubt about endocrine disrupter science – A rebuttal of industry-sponsored critical comments on the UNEP/WHO report “State of the Science of Endocrine Disrupting Chemicals 2012” Regul. Toxicol. Pharmacol. 73: 1007-1017.

Blanchfield, P.J., K.A. Kidd, M. Docker, V.P. Palace, B.J. Park, and L.D. Postma.  2015. Recovery of a wild fish population from whole-lake additions of the potent estrogen in the birth control pill.  Environ. Sci. Technol. 49(5): 3136-3144.

Müller, A.-K., M. Brinkmann, L. Baumann, M.H. Stoffel, H. Segner, K.A. Kidd and H. Holler. 2015. Ultrastructural alterations in tissues of yellow perch (Perca flavescens) from a biological mercury hotspot. Env. Sci. Poll. Res.  1-13.

Lescord, G.L., K.A. Kidd, A.O. De Silva, C. Spencer, M. Williamson, X. Wang, and D. C.G. Muir. 2015. Perfluorinated and polyfluorinated compounds in lake food webs in the Canadian high Arctic. Environ. Sci. Technol. 49(5):2694–2702.

Kidd, K.A. 2015. In Response: Environmental and biological considerations for active pharmaceutical ingredients in the environment and their effects across multiple biological scales: An academic perspective. Environ. Toxicol. Chem. 34(3):461-463. Invited Perspectives Paper.

Lescord, G.L., K.A. Kidd, J.L. Kirk, N.J. O’Driscoll, X. Wang, and D.C.G. Muir. 2015. Factors affecting biotic mercury concentrations and biomagnification through six lake food webs in the Canadian high Arctic. Sci. Total Environ. 509–510:195–205.

Clayden, M., L. Arsenault, K.A. Kidd, M. Mallory, and N. O’Driscoll. 2015. Mercury bioaccumulation and biomagnification in the food web of a small Arctic polynya ecosystem. Sci. Total Environ. 509-510:206-215.


Zoeller, R.T., Å. Bergman, G. Becher, P. Bjerregaard, R. Bornman, I. Brandt, T. Iguchi, S. Jobling, K.A. Kidd, A. Kortenkamp, N.E. Skakkebaek, J. Toppari, and L.N. Vandenberg. 2014. The debate over health impacts of endocrine disrupting chemicals: a path forward.  Environ. Health. 13:118

Van Geest, J.L., L.E. Burridge, F.J. Fife, and K.A. Kidd. 2014. Feeding response in marine copepods as a measure of acute toxicity of four anti-sea lice pesticides. Mar. Env. Res. 101:145-152.

Van Geest, J.L., L.E. Burridge, and K.A. Kidd. 2014. Toxicity of two pyrethroid-based anti-sea lice pesticides, AlphaMax® and Excis®, to a marine amphipod in aqueous and sediment exposures.  Aquaculture 434: 233–240.

Clayden, M.G., K.A. Kidd, B. Wyn, J.L. Kirk, D.C.G. Muir, and N.J. O’Driscoll.  2014. Response to comment on “Mercury biomagnification through food webs is affected by physical and chemical characteristics of lakes.”  Environ. Sci. Technol. 48(17):10526-10527.

Kidd, K.A., M. J. Paterson, M. D. Rennie, C.L. Podemski, D.L. Findlay, P.J. Blanchfield, and K. Liber. 2014. Direct and indirect responses of a freshwater food web to a potent synthetic oestrogen.  Phil. Trans. Royal Soc. B. 1656: 20130578. Invited.

Baker, L., J. Mudge, J. Houlahan, D. Thompson, and K.A. Kidd. 2014. Direct and indirect effects of a glyphosate-based herbicide and nutrients on Chironomidae (Diptera) emerging from small wetlands.  Environ. Toxicol. Chem. 33(9):2076–2085.

Van Geest, J.L., L.E. Burridge, and K.A. Kidd. 2014. The toxicity of the anti-sea lice pesticide AlphaMax® to the polychaete worm Nereis virens. Aquaculture 430:98-106.

Clayden, M.G., K.A. Kidd, J. Chételat, B.D. Hall and E. Garcia. 2014. Environmental, geographic and trophic influences on methylmercury concentrations in macroinvertebrates from lakes and wetlands across Canada. Ecotoxicology 23:273–284.

Loughery, J.R., T.J. Arciszewski, K.A. Kidd, A. Mercer, L.M. Hewitt, D.L. MacLatchy, and K.R. Munkittrick. 2014. Understanding the chronic impacts of oil refinery wastewater requires consideration of sediment contributions to toxicity.  Arch. Env. Contam. Toxicol. 66(1):19-31.

Jardine, T.D., W.L. Hadwen, S.K. Hamilton, S. Hladyz, S.M. Mitrovic, K.A. Kidd, W.Y Tsoi, M. Spears, D.P. Westhorpe, V.M. Fry, F. Sheldon, and S.E. Bunn. 2014. Understanding and overcoming baseline isotopic variability in running waters.  River Res. Appl. 30(2)155-165.


Lavoie, R.A., T.D. Jardine, M.M. Chumchal, K.A. Kidd, and L.M. Campbell. 2013. Biomagnification of mercury in aquatic food webs: a worldwide meta-analysis.  Environ. Sci. Technol. 47 (23), pp 13385–13394.  Editors’ Choice, Science Magazine, 15 Nov 2013.

Clayden, M.G., K.A. Kidd, B. Wyn, J.L. Kirk, D.C.G. Muir, and N.J. O’Driscoll. 2013. Mercury biomagnification through food webs is affected by physical and chemical characteristics of lakes.  Environ. Sci. Technol. 47:12047−12053.

Bergman A., A. M. Andersson, G. Becher, M. van den Berg, B. Blumberg, P. Bjerregaard, C.G. Bornehag, R. Bornman, I. Brandt, J.V. Brian, S.C. Casey, P. Fowler, H. Frouin, L.C. Giudice, T. Iguchi, U. Hass, S. Jobling, A. Juul, K.A. Kidd, A. Kortenkamp, et al: 2013. Science and policy on endocrine disrupters must not be mixed: a reply to a “common sense” intervention by toxicology journal editors. Environ. Health 2013, 12(69)1-4.

Schein, A., S.C. Courtenay, K.A. Kidd, K.A. Campbell, and M.R. van den Heuvel. 2013. Food web structure within an estuary of the southern Gulf of St. Lawrence undergoing eutrophication. Can. J. Fish. Aquat. Sci. 70(12):1805-1812.

Servos, M.R., K.R. Munkittrick, G. Constantin, R. Mngodo, N. Aladin, S. Choowaew, N. Hap, K.A. Kidd, E. Odada, O. Parra, G. Phillips, S. Ryanzhin, and R. Urrutia. 2013. Science and management of transboundary lakes: lessons learned from the Global Environment Facility program. Environ. Development 7:17-31.

Batchelar, K.L., K.A. Kidd, K.R. Munkittrick, P.E. Drevnick, and N.M. Burgess. 2013. Reproductive health of yellow perch (Perca flavescens) from a biological mercury hotspot in Nova Scotia, Canada. Sci. Total Env. 454–455:319–327.

Bergman, A., J.J. Heindel, T. Kasten, K.A. Kidd, S. Jobling, M. Neira, R.T. Zoeller, G. Becher, P. Bjerregaard, R. Bornman, I. Brandt, A. Kortenkamp, D. Muir, M.-N. Brune Drisse, R. Ochieng, N.E. Skakkebaek, A. Sundén Byléhn, T. Iguchi, J. Toppari, and T.J. Woodruff. 2013. The impact of endocrine disruption: A consensus statement on the state of the science. Env. Health Persp. 121(4):A104-A106.

Jardine, T.D., K.A. Kidd, and N. O’Driscoll. 2013. Food web analysis reveals effects of pH on mercury bioaccumulation at multiple trophic levels in streams.  Aquat. Toxicol. 132-133:46-52.

Batchelar, K.L., K.A. Kidd, P.E. Drevnick, K.R. Munkittrick, N.M. Burgess, A.P. Roberts, and J.D. Smith. 2013. Evidence of impaired health in yellow perch (Perca flavescens) from a biological mercury hotspot in northeastern North America.  Environ. Toxicol. Chem. 32(3):627–637.

Ryan, M.J., G.A. Stern, M.V. Croft, K.A. Kidd, S. Gewurtz, M. Diamond, and P. Roach. 2013. Biotic interactions in temporal trends (1992-2010) of organochlorine contaminants in the aquatic food web of Lake Laberge, Yukon Territory. Sci. Total Environ. 443:80–92.


Cabrera Páez, Y., C. Aguilar Betancourt, G. González-Sansón, K. Kidd, K. Munkittrick, and R. A. Curry. 2012. Elevated mercury, body size and changes in trophic structure of Gambusia puncticulata (Poeciliidae) along the Almendares River, Havana, Cuba. Arch. Environ. Contam. Toxicol. 63(4):523-533, DOI 10.1007/s00244-012-9801-4.

Kidd, K.A., D.C.G. Muir, M.S. Evans, X. Wang, M. Whittle, H.K. Swanson, T. Johnston and S. Guildford. 2012. Biomagnification of mercury through lake trout food webs with different physical, chemical and biological characteristics.  Sci. Total Environ. 438:135–143.

Clements, W.H., C.W. Hickey and K.A. Kidd.  2012. How do aquatic communities respond to contaminants?  It depends on the context.  Environ. Toxicol. Chem. 31(9):1-9. Invited Focus Article.

Jardine, T.D., K.A. Kidd, and J.B. Rasmussen. 2012. Terrestrial organic matter in the diet of stream consumers: Implications for mercury bioaccumulation.  Ecol. Appl. 22(3): 843-855.

Borgå, K., K.A. Kidd, D.C.G. Muir, O. Berglund, J.M. Conder, F.A.P.C. Gobas, J. Kucklick, O. Malm, and D.E. Powell. 2012. Trophic magnification factors: Considerations of ecology, ecosystems and study design. Int. Environ. Assess. Manag.  8(1):64-84.

Burkhard, L.P., C. Cowan-Ellsberry, M.R. Embry, R.A. Hoke, and K. Kidd. 2012. Bioaccumulation data from laboratory and field studies: Are they comparable? Int. Environ. Assess. Manag.  8(1):13-16.


Diamond, J.M., H.A. Latimer, K.R. Munkittrick, K.W. Thornton, S.M. Bartell, and K.A. Kidd. 2011. Prioritizing organic chemicals of emerging concern for ecological screening assessments. Environ. Toxicol. Chem. (30)11:2385-2394,

Arciszewski, T.J., K.A. Kidd and K.R. Munkittrick. 2011. Comparing responses in the performance of sentinel populations of stoneflies (Plecoptera) and slimy sculpin (Cottus cognatus) exposed to enriching effluents. Ecotoxicol. Environ. Saf. 74:1844–1854.

Swanson, H.K., K.A. Kidd, and J.D. Reist. 2011. Quantifying importance of marine prey for two partially anadromous fishes. Can. J. Fish. Aquat. Sci.  68: 2020–2028.

Swanson, H.K., N. Gantner, K.A. Kidd, D.C.G. Muir, and J.D. Reist.  2011. Comparison of mercury concentrations in landlocked, resident, and searun fishes (Salvelinus spp.) from Nunavut, Canada Environ. Toxicol. Chem. 30(6): 1459–1467.

Jardine, T.D. and K.A. Kidd. 2011. Low concentrations of selenium in stream food webs of eastern Canada. Sci. Total Environ. 409: 785-791.


My research program focuses on understanding the impacts of human activities on aquatic ecosystems. More specifically, my students and I study the effects of point (municipal, industrial) and non-point (agriculture, forest harvesting) discharges on the health of aquatic organisms, and the fate of persistent pollutants in freshwater and marine ecosystems. Much of our research is multidisciplinary in nature and an interface between biogeochemistry, chemistry, ecology and toxicology. For example, we use measurements of stable nitrogen, sulfur, hydrogen and carbon isotope ratios in organisms to characterize trophic relationships in diverse aquatic systems and to understand pollutant accumulation from primary producers through to top predators. I have led or been involved in three major whole ecosystem experiments to understand how 1) the estrogen used in the birth control pill affects fish and their prey, 2) wastes from rainbow trout aquaculture affect native organisms, and 3) a commonly-used herbicide and fertilizers affect the health of wetland communities.

Contaminants in Aquatic Food Webs

Some contaminants can concentrate up through food webs to levels in fish that can affect the health of the fish themselves or that of fish-eating wildlife and humans. Even in remote systems with no human activities, mercury and other contaminants can be high in fish leading to concerns over risks to human and wildlife health. We have several ongoing projects to understand how contaminants are accumulated through aquatic food webs into top predators and their effects on fish.

• Mercury in lakes in Atlantic Canada – We are working in Kejimkujik National Park, Nova Scotia, an area known as a mercury hotspot, and developing novel approaches for understanding how mercury moves through the food webs of these acidic lakes and whether it is adversely affecting the health of the fish.
• Mercury in the Canadian Arctic – We have studied mercury in an important subsistence fish – the Arctic char – and its prey to understand why fish from some lakes are more contaminated than others.
• Mercury in coastal regions of Patagonia, Mexico, and Antarctica – We are assessing the levels of mercury and other metals in marine fish and invertebrates, some of which are consumed by local communities.
• Other global studies on mercury – My group and I also have ongoing research across a latitudinal gradient in Norway and Sweden to understand the effects of climate and organic matter on mercury cycling in lakes, and collaborations to assess global patterns of mercury in freshwater and marine food webs.
• Nutrients and metals from aquaculture – At several salmon aquaculture sites in the Bay of Fundy, we are examining the exposure of nearby organisms to both nutrients and metals from wastes.

Contaminants of emerging concern – including estrogens and their mimics – in municipal wastewater treatment plant (MWTP) effluents have the potential to disrupt the normal function of endocrine systems and impair reproduction and development in fish and other organisms. Approaches are needed to understand whether these chemicals are causing biological effects downstream of MWTPs, and to prioritize sites for further work.

My lab is involved in a collaborative program through the Canadian Water Network to identify a suite of measures that clearly indicate that biological effects are occurring as a result of the presence of effluent discharges, and a practical basis for distinguishing the relative level of concern among sites. In addition, we conducted a whole ecosystem experiment at IISD-Experimental Lakes Area in northwestern Ontario over 12 years to assess the effects of the estrogen used in the birth control pill – EE2 – on fish populations and the food web.

Funding: These projects have been supported by NSERC Discovery & Strategic Network Grants, New Brunswick Environmental Trust Fund, New Brunswick Wildlife Trust Fund, INAC Northern Contaminants Program, Polar Continental Shelf Project, Fisheries & Oceans Canada, Schering Pharmaceutical, Environment Canada, Parks Canada, Canadian Water Network, Norwegian Research Council, and Fundación MERI Chile.

Forest management and stream health

Nearly two-thirds of Canada’s land base is forested, and this forms the basis of one of Canada’s most important resource industries. However, forests are also key suppliers of aquatic ecosystem services (AES), such as serving as critical source areas for much of North America’s sustainable, clean water supplies and supporting aquatic biodiversity. This research is providing information on how forest management activities affect aquatic ecosystems to inform sustainable forest management practices.

Through several projects in New Brunswick and Ontario, we are exploring 1) the change in physical, chemical and biological indicators (water quality though food web structure) of stream health across a gradient of forest disturbance, and 2) the cumulative effects of forest management practices on downstream ecosystems and their services (fish and invertebrate communities, water quality, mercury accumulation, carbon inputs and cycling), using intensively- through minimally-managed watersheds on forested landscapes.

Funding: This research is supported by an NSERC Strategic Network grant, an NSERC CRD and considerable in-kind support from the Canadian Forest Service (NRCan) and JD Irving, Ltd.

Dams and dam removal

In Canada, there are > 10,000 known dams, > 580 of which are large hydroelectric facilities. Much of this infrastructure is aging and will require removal or replacement in the decades to come, motivating an emerging field in Canada and abroad – the science of dam removal. One such facility – the Mactaquac Dam – is on the Saint John River in New Brunswick, and it will reach the end of its service life in 2030.

The Mactaquac Aquatic Ecosystem Study (MAES) is a whole ecosystem study to understand the structure and function of the Saint John River and the potential implications of removal of the Mactaquac Dam upstream of Fredericton. As part of this multi-disciplinary, multi-institutional project we are assessing the structure of the riverine food web and the contemporary and historical concentrations of metals, hydrocarbons and chlorinated organics (e.g. PCBs) in the sediments of the headpond. These results will be used to support the decisions around dam removal or refurbishment.
Funding: This project is led by the Canadian Rivers Institute @ UNB and funded by NB Power and by an NSERC CRD Grant.