1. Program for Chemical and Environmental Toxicology, Department of Biology, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada, Sedna Ecological, Inc., P.O. Box 74280, Fairbanks, Alaska 99707, Centre for Environmental Modelling and Chemistry, Trent University, Peterborough, Ontario K9J 7B8, Canada, and Canadian Wildlife Service, Environment Canada, Iqaluit, Nunavut X0A 0H0, Canada