1. Department of Fisheries and Oceans, Arctic Aquatic Research Division, Winnipeg, MB, R3T 2N6 Canada, Department of Environment and Geography, University of Manitoba, Winnipeg, MB R3T 2N2 Canada, Wellington Laboratories Incorporated, Research Division, Guelph, ON, N1G 3M5, Canada, Department of Chemistry, University of Guelph, Ontario, ON, N1G 2W1, Canada, Environment Canada, Burlington, ON, L7R 4A6 Canada, and Food Research Division, Health Canada, Ottawa, ON, K1A 0L2 Canada