Pollutants released to the environment are distributed among the many environmental media such as air, water, soil, and vegetation, as the result of complex physical, chemical and biological processes. The possible environmental impact associated with chemical pollutants is related to their concentration levels and persistence in the various environmental compartments. Therefore, information regarding the migration of pollutants across environmental phase boundaries (eg., air-water, soil-water) and their accumulation in the environment is essential if we are to assess the potential environmental impact and the associated risks. In recent years it has become apparent that environmental pollution is a multimedia problem. Risk assessment and the design of appropriate pollution control measures require that we carefully consider the transport and accumulation of pollutants in the environment. We are now recognizing that the environment must be considered as a whole, and the scientific and regulatory approaches must consider the interactions of environmental media. It is also becoming apparent that single-medium approaches are partial and often counter-productive. On the other hand any multimedia program must carefully consider the rate of each environmental medium in the overall multimedia scheme.