Since the 1940’s, there have been releases of anthropogenic radionuclides to the environment as a result of nuclear weapons production and research, nuclear power and nuclear fuel reprocessing, and other uses of radioisotopes, such as medical uses. The levels of radionuclides in the environment are of great concern, especially as little is known about what the long-term behaviour and effects on the human population will be, and there is widespread suspicion that anthropogenic radionuclides are at least partly responsible for increased leukaemia incidence around several nuclear installations. There have been both controlled releases to the environment, such as those from the Sellafield reprocessing plant in Cumbria, the Mayak Nuclear weapons facility in Russia and AWE Aldermaston in England, and accidental releases, such as the Chernobyl accident in 1986, the Chelyabinsk (Kyshtym) accident in 1957, the Windscale fire of 1957, and particulate releases from Windscale in the 1950’s. The major contribution to artificial radionuclides in the environment world-wide, however, has been from fallout from nuclear weapons testing.

In this thesis, releases from three main sources are investigated, namely the Chernobyl accident, the Mayak installation and AWRE Aldermaston. Various methods for the determination of environmental radionuclides are also examined, including a new application of Accelerator Mass Spectrometry in the determination of trace plutonium.