This report is part of a larger study of the role of research and development in the Environmental Protection Agency. This report deals with research needed on the transport, transformation, and accumulation of pollutants in the environment. The report's principal objectives are to suggest a systematic method for identification and organization of existing knowledge and or priority research, apply the material to selected classes of pollutants for illustration of the suggested planning principles, and comment on the limitations and needs in government research administration and management.