Areas In Europe With Elevated Levels Of Natural Radionuclides

摘要

The amount of natural radioactivity in mineral and drinking water depends on the source of the water. Besides the geological formation, the water's redox potential, oxygen concentration, temperature and the formation's permeability can influence the amount of radionuclides found. The distribution of uranium, radium and radon in European ground and drinking waters suggests a pattern. Values from Finland (Salonen, 1994), Sweden (Andrews et al, 1989), western Spain (Fernandez et al, 1992) and Ukraine (Zelensky et al, 1992) in particular show a close relationship between high radionu-clide levels in water and basement rock areas dominated by granitoids. Granitoid-dominated basement rock areas are typical geological settings for cores or eroded roots of mountain-forming (orogenic) areas. The most important European examples are the Baltic shield and the Moldanubian zone of the Hercynian orogeny (late Devonian - Carboniferous areas, i.e. 408-362 million years ago to 362-290 million years ago). Another hint for defining areas with potentially high levels of natural radio-nuclides in ground-water is the distribution of the main European uraniferous districts. A summary of the main uraniferous deposits in Europe was undertaken by Ziegler (1984), updated by Raff in 1999 (Raff,1999a and Raff,1999b).To identify those'European regions where high levels of natural radionuclides in groundwater might occur, a continent-wide map was drawn by Raff (1999), presenting the main European basement rock areas and uraniferous deposits (Figure 1).