Extraordinary enrichment of natural radionuclides in thermal water pipes

Natural radionuclides in corroded thermal water pipes of a health spa in Germany have been investigated for the first time. The proven enrichment of radon-222 in the water supply system stems from radium-226 incrustations in the relatively old water pipes. The activity of radium-226 in these incrustations is extraordinarily high and amounts to 13 Bq/g. Due to these incrustations, radon-222 is permanently produced by the deposited radium-226 and released to the surrounding thermal water. The detected radium-226-concentrations of the thermal water range in the order of 10-30 Bq/l and are among the highest radium-concentrations in waters of Germany. The main reason for the radium-enrichment is the absence of oxygen in the studied thermal waters. Within the water pipe system, Radium precipitates simultaneously with iron- and manganese-oxides, due to additionally occurring oxygen. (orig.)