1. Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario, M5S 3H6, Department of Fisheries & Oceans, Great Lakes Laboratory for Fisheries and Aquatic Sciences, 867 Lakeshore Road, Burlington, Ontario, L7R 4A6, Ontario Ministry of the Environment, Laboratory Services Branch, 125 Resources Road, Etobicoke, Ontario, M9P 3V6, and Water Science and Technology Directorate, Environment Canada, 867 Lakeshore Road, Burlington, Ontario, L7R 4A6