1. Clinical Instructor, Department of Preventive Medicine and Comprehensive Health Care, University of Colorado School of Medicine, Denver, Colorado 80262.
2. Director, Analytical Laboratory, Environmental Trace Substances Research Program, University of Colorado, Boulder, Colorado 80309.
3. Assistant Clinical Professor, Departments of Pediatrics and Preventive Medicine, University of Colorado School of Medicine, Denver, Colorado 80262.
4. Director, Environmental Trace Substances Research Program, University of Colorado, Boulder, Colorado 80309; Professor, Department of Physics, University of Colorado, Denver, Colorado 80202; and Adjoint Professor, Department of Preventive Medicine, University of Colorado School of Medicine, Denver, Colorado 80262.