1. U.S. Environmental Protection Agency, Region 8, Denver, Colorado, USA
2. U.S. Environmental Protection Agency, Office of Research and Development, National Exposure Research Laboratory, Research Triangle Park, North Carolina, USA
3. Alion Science and Technology, Durham, North Carolina, USA
4. U.S. Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory Research Triangle Park, North Carolina, USA
5. Senior Environmental Employment Program, Research Triangle Park, North Carolina, USA
6. U.S. Environmental Protection Agency, Region 6, Dallas, Texas, USA