1. Department of Chemistry, University of Toronto, 80 St. George Street, Lash Miller Building, Toronto, Ontario M5S 3H6, Canada, Department of Environmental Biology, University of Guelph, Bovey Building, Guelph, Ontario, N1G 2W1, Canada, Canadian Wildlife Service, Environment Canada, National Wildlife Research Centre, Carleton University, Ottawa, Ontario K1A 0H3, Canada, and National Water Research Institute, Environment Canada, 867 Lakeshore Road, Burlington, Ontario L7R 4A6, Canada