1. Exposure Assessment Research Division, Environmental Monitoring Systems Laboratory, U.S. Environmental Protection Agency, Las Vegas, NV 89109
2. Department of Life Sciences, Midwest Research Institute, Kansas City, MO 64110
3. Environmental Chemistry and Toxicology Laboratory, Department of Chemistry Texas Southern University, Houston, TX 77004
4. Office of Pesticides and Toxic Substances, Chemical Management Division, U.S. Environmental Protection Agency, Washington, DC 20460