1. Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario, Canada M5S 3H6, CLF-Chem Consulting, 28 Rue Edouard Olivier, Brussels, Belgium BE-1170, Geological Survey of Canada, 601 Booth Street, Ottawa, Ontario, Canada K1A 0E8, and Water Science and Technology Directorate, Environment Canada, 867 Lakeshore Drive, Burlington, Ontario, Canada L7R 4A6