1. Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada, Environment Canada, Water Science and Technology Directorate, 867 Lakeshore Road, Burlington, Ontario L7R 4A6, Canada, Environment Canada, Canadian Wildlife Service, Edmonton, Alberta T6H 3S5, Canada, and Nunavik Research Centre, Kuujjuaq, Quebec J0M 1C0, Canada