The rapid growth of the world population - nearly six-fold over the last hundred years - combined with the rising number of technical installations especially in the industrialized countries has lead to ever tighter and more strained living spaces on our planet. Because ofthe inevitable processes oflife, man was at first an exploiter rather than a careful preserver of the environment. Environmental awareness with the intention to conserve the environment has grown only in the last few decades. Environmental standards have been defined and limit values have been set largely guided, however, by scientific and medical data on single exposures, while public opinion, on the other hand, now increasingly calls for astronger consideration of the more complex situations following combined exposures. Furthermore, it turned out that environmental standards, while necessarily based on scientific data, must also take into account ethical, legal, economic, and sociological aspects. A task of such complexity can only be dealt with appropriately in the framework of an inter­ disciplinary group.

1 Methodological Foundations of Defining Environmental Standards.- 2 Scientific and Medical Foundations.- 3 Perception of Technical Risks.- 4 The Importance of Economic Factors in Setting Combined Environmental Standards.- 5 Legal Problems of Assessing and Regulating Exposure to Combined Effects of Substances and Radiation.- 6 Appraisal and Recommendations.- Authors.