Anthropogenic Radiocarbon: Past, Present, and Future

Abstract

14 C is one of the most important anthropogenic radionuclides released to the environment by human activities. Weapon testing raised the 14 C concentration in the atmosphere and biosphere to +100% above the natural level. This excess of atmospheric C at present decreases with a half-life of ca 7 years. Recently, a new source of artificially produced 14 C in nuclear reactors has become important. Since 1967, the Bratislava 14 C laboratory has been measuring 14 C in atmospheric 14 CO 2 and in a variety of biospheric samples in densely populated areas and in areas close to nuclear power plants. We have been able to identify a heavy-water reactor and the pressurized water reactors as sources of anthropogenic 14 C. 14 C concentrations show typical seasonal variations. These data are supported by measurements of 3 H and 85 Kr in the same locations. Results of calculations of future levels of anthropogenic 14 C in the environment due to increasing nuclear reactor installations are presented.