For his leadership in separations science and technology; for improving nuclear fuel recycling and waste removal; and for leading the development process that was instrumental in the cleanup of waste at the Savannah River Site.
For his innovation in the production and application of medical isotopes; for advancing the separation and purification of actinides and heavy elements; and for his leadership in the use of alpha emitters to save the lives of cancer patients.
For his broad scientific contributions and international reputation in aqueous chemistry and geochemistry; for his research into the structure, dynamics, and reactions at fluid–solid interfaces; and for his leadership and service to ORNL and the international scientific community.
For distinguished research in the field of risk assessment, including pharmacokinetic and pharmacodynamic models, interspecies extrapolation, and human exposure to dioxin and other background contaminants, and for significant contributions to environmental policy through pioneering investigations of the effectiveness of remediation technologies and through service on national and international advisory panels and boards
For pioneering research in ecosystem theory, ecological modeling, error analysis, hierarchy theory, and landscape ecology and for the development of basic applications in risk assessment and regional environmental analysis.