Sampling and measurement of long-lived radionuclides in environmental samples

The volatile and semivolatile long-lived man-made radionuclides /sup 3/H, /sup 14/C, /sup 79/Se, /sup 85/Kr, /sup 99/Tc, /sup 129/I, /sup 135/Cs, and /sup 137/Cs are of concern in operation of nuclear facilities because they are difficult and expensive to contain and once emitted to the environment they become permanent ecological constituents with both local and global distributions. Species-selective sampling and analytical methods (radiochemical, neutron activation, and mass spectrometric) have been developed for many of these nuclides with sensitivities well below those required for radiation protection. These sampling and analytical methods have been applied to the measurement of current environmental levels of some of the more ecologically important radionuclides. The detection and tracing of long-lived radionuclides is being conducted in order to establish base-line values and to study environmental behavior. This paper describes detection and measurement techniques and summarizes current measurement results.