Assessing environmental radioactivity

A great deal of progress has been made in methods for determining radionuclides during the thirty years since the first atmospheric tests of nuclear weapons. With time our understanding of environmental contamination itself has changed. Development of instrumentation has provided new opportunities for detecting radionuclides rapidly and without radiochemical separation. On the other hand, there are also a number of methods which have remained unchanged throughout this thirty year period. The location of the laboratories where measurements will be made is of great importance. A well equipped central laboratory is capable of analysing all known environmental radionuclides, whereas remote local control laboratories are only able to maintain the expertise needed for limited measurement methods. The activity level in the environmental samples determines the methods which can be used. In an emergency situation simple monitoring can be performed on the basis of simple total activity measurements. The estimation of intervention levels in cases of food contamination requires more detailed assessment methods. Reliable methods of sample collection and analysis are necessary in such cases. Direct gamma spectrometric determination is usually sufficient for monitoring purposes. The levels to be determined in radioecological studies, however, are often so low that the most sophisticated radiochemical separation and measurement methods are needed. (author). 8 refs, 2 figs, 2 tabs