A review is presented of factors which have combined to create an incentive for the applying of mass balance modelling concepts to elucidating the sources, fate, and effects of contaminants in the environment. These factors include increased understanding of environmental processes, availability of better data on contaminant properties and toxicology, changes in regulatory approaches, growth in computing power, and the demand for comprehensive education on environmental issues. It is suggested that a set of compatible models may be emerging which treat QSARs and QSPRs; far-field, regional and global processes; near-field or local processes including bioaccumulation; and finally human exposure. Recommendations are made for actions which will enhance the use of mass balance models as an integral part of increasing our scientific understanding of chemical behaviour in the environment and especially contributing to improved chemical stewardship in the environment.