Dean S. Jeffries

Research Scientist - Group Leader, Acid Rain Aquatic Effects
Environment and Climate Change Canada

Current research and/or projects

Contributing to Environment Canada’s mandate to reduce the risks to Canadians and their environment posed by air pollutants, particularly acid rain

  • Turkey Lakes Watershed (TLW) Study including lake mass budgets, chemical trends, and ecosystem acidification and recovery processes
  • Chemical status and acid sensitivity of Canadian Shield lakes in western Canada
  • Regional assessment of aquatic ecosystem acidification and recovery
  • Technical information for Canada / US Air Quality Agreement Progress Reports and scientific assessments by the United Nations Economic Commission for Europe (UN ECE) International Cooperative Program (ICP) on Acidification of Lakes and Rivers
  • Research collaborations: nitrogen-based acidification (University of Waterloo); lake recovery processes (Department of Fisheries and Oceans - Freshwater Institute); topographic controls on watershed responses to acid rain (University of Western Ontario)

Professional activities / interests

Expertise: environmental geochemistry, chemical limnology, precipitation chemistry; acid rain aquatic effects; lake and watershed mass budgets; and acidification assessments

Member of the UN Economic Commission for Europe ICP Taskforce on Acidification of Lakes and Rivers

Research grant and journal paper reviews; guest editor of journal special volumes

Chairman of the Turkey Lakes Watershed Study Steering Committee

Education and awards

B.Sc., Chemistry and Geology (Hons.), McMaster University, Hamilton, ON

Ph.D., Geochemistry, McMaster University, Hamilton, ON

Environment Canada, Citation of Excellence, 1997

Key publications

Jeffries, D.S., D.K. McNicol and R.C. Weeber. 2005. Chapter 6: Effects on Aquatic Chemistry and Biology, p. 203-278. In 2004 Canadian Acid Deposition Science Assessment. Environment Canada, Ottawa, Ontario.

Jeffries, D.S. and R. Ouimet. 2005. Chapter 8: Critical Loads – Are they being exceeded? p. 341-368. In 2004 Canadian Acid Deposition Science Assessment. Environment Canada, Ottawa, Ontario.

Jeffries, D.S., T.A. Clair, S. Couture, P.J. Dillon, J. Dupont, W. Keller, D.K. McNicol, M.A. Turner, R. Vet and R. Weeber. 2003. Assessing the recovery of lakes in south-eastern Canada from the effects of acidic deposition. Ambio. 32(3): 176-182.

Jeffries, D.S., T.G. Brydges, P.J. Dillon and W. Keller. 2003. Monitoring the results of Canada/U.S.A. acid rain control programs: some lake responses. Environ. Monit. Assess. 88:3-19.

Jeffries, D.S., R.G. Semkin, F.D. Beall and J. Franklyn. 2002. Temporal trends in water chemistry in the Turkey Lakes Watershed, Ontario, Canada, 1982-1999. Wat. Air Soil Pollut.: Focus. 2(1):5-22.

Jeffries, D.S., D.C.L. Lam, I. Wong and M.D. Moran. 2000. Assessment of changes in lake pH arising from present levels of and expected reductions in acidic deposition. Can. J. Fish. Aquat. Sci. 57(2):40-49.