1. U.S. Environmental Protection Agency; National Health and Environmental Effects Research Laboratory, Western Ecology Division; Corvallis OR USA
2. U.S. Geological Survey; Northern Prairie Wildlife Research Center; Jamestown ND USA
3. U.S. Geological Survey; Geosciences and Environmental Change Science Center; Lakewood CO USA
4. U.S. Environmental Protection Agency; National Exposure Research Laboratory; Las Vegas NV USA
5. U.S. Geological Survey; National Research Program; Lakewood CO USA
6. U.S. Environmental Protection Agency; National Center for Environmental Assessment; Arlington VA USA