Natural Radioactivity in Drinking Water in the Surroundings of a Metamorphic Outcrop in Hungary: The Hydrogeological Answer to Practical Problems

Groundwater quality constantly evolves through rock–water interactions, which can enrich groundwater with undesirable elements such as naturally occurring radionuclides. The aim of this study was to understand the cause gross alpha activity exceeding screening value 0.1 Bq L−1 measured in groundwater-derived drinking water vicinity a metamorphic outcrop Hungary. As is strongly dependent on properties flow systems, environmental tracers (δ2H and δ18O composition, 226Ra, 222Rn, total U concentration, 234U/238U ratio) hydraulic evaluation were applied dynamics. collected samples had activities up 540 mBq L−1, translates into an indicative dose below parametric value. However, presence dissolved uranium, δ2H (−52.6–(−83.4)) (−7.17–(−11.96)) values led conclusion that local systems sampled are known be most vulnerable any changes their recharge area. results confirm system approach involving powerful tool for identifying natural radioactivity water.