1. Ottawa-Carleton Chemistry Institute, Department of Chemistry, Carleton University, Ottawa, Ontario, K1S 5B6, Canada (D.M.G., C.L.C., D.M.H); Institute for Environmental Chemistry, National Research Council of Canada, Ottawa, Ontario, K1A 0R9, Canada (R.E.S.); and Geological Survey of Canada, 601 Booth Street, Ottawa, Ontario, K1A 0E8, Canada (D.C.G.)