Distribution of uranium in German bottled and tap water

The results presented in this paper on uranium in bottled and tap water were determined within the scope of the project “European Groundwater Geochemistry: Bottled Water” of the Geochemistry Expert Group of EuroGeoSurveys. The analyses of bottled water provide an inexpensive approach to obtain information about European groundwater geochemistry. For this study, the uranium concentrations in 1785 European mineral water samples were analyzed by ICP–QMS in the BGR laboratories. The dataset is used to obtain a first impression about natural concentration levels and variation of uranium in groundwater (and bottled water) at the German and European scale.A range of < 0.0005–16.0 µg U/L (median 0.17 µg/L) was obtained in 908 bottled water samples in Germany. A range of 0.00115–9.0 µg U/L (median 0.073 µg U/L) was obtained for tap water from 163 municipal tap water systems. The regional distribution of uranium in the analyzed bottled and tap water is influenced primarily by lithological (Bunter and Keuper strata, crystalline basement rocks, Permian strata, and loess) and anthropogenic (old mining districts, phosphate fertilizers, and industrial emissions) factors. Elevated uranium concentrations (> 2 µg U/L) in bottled water have geological sources and were found in Hesse, Thuringia, North Rhine–Westphalia, Saxony, southern part of Saxony–Anhalt and in Baden–Württemberg (Black Forest). Bunter and Keuper sandstone are the main source of uranium, followed by Permian and crystalline basement aquifers. The EU Guidelines for Drinking Water and the German Drinking Water Regulations give no upper limit for uranium; however, a provisional value of 15 µg U/L exists in the Guidelines for Drinking Water Quality of the World Health Organization. The only value for German bottled water is 2 µg U/L, above which the label may not say that the water may be used for the preparation of baby food. Nevertheless the uranium content of bottled and tap water needs to be monitored and controlled by governmental offices. In all, 14% of all the analyzed German bottled water samples contain > 2 µg U/L and 15% of all analyzed European bottled water. Only one German bottled mineral water sample exceeded the guideline value of 15 µg U/L in 2008.