The recognition of potential long-term effects of substance, has led to the development of regulation and legislation wich emphasis to need for assessing the ricks posed by both new and existing substance for man and the environment. The evaluation of fate and exposure models is put into perspective in relation to the developments over the last five years in the framework of the EU regulation and national legislation within of environmental exposure models (multi-media models)is decribed in the context of cuallity assurance of models available to user group, wich is different from the qualitty assurance aspects for a developers group