Occurrence of natural radioactivity in public water supplies in Germany: 238U, 234U, 235U, 228RA, 226RA, 222RN, 210PB, 210PO and gross activity concentrations

Abstract

The Federal Office for Radiation Protection performed a representative survey on the radiological quality of drinking water in Germany. The aim of this study was to determine regional variations of natural radionuclide concentrations and to estimate radiation exposures caused by drinking water consumption. The study includes analyses of the natural radionuclides ²³⁸U, ²³⁴U, ²³⁵U, ²²⁸Ra, ²²⁶Ra, ²²²Rn, ²¹⁰Pb, ²¹⁰Po and of gross α activity concentrations in drinking water from 564 public water supplies. This represents 3 % of all German water supplies providing about 37 Mio. inhabitants. Results on ranges, medians and distributions of radionuclide concentrations of drinking water as well as age-dependent ingestion and inhalation doses estimated for members of the public are presented. Generally, the dose due to uranium isotopes is negligibly low. Radiation exposures are predominantly caused by ²²²Rn, ²²⁸Ra, ²¹⁰Po and ²¹⁰Pb. The ingestion dose deduced for adults (>17 a) and infants (0–1 a) is dominated by ²²²Rn and ²²⁸Ra, respectively. A gross α activity analysis procedure using liquid scintillation counting has been tested. Measured gross α activities values were found to be well related to the summarised activities of ²³⁸U, ²³⁴U, ²²⁶Ra and ²¹⁰Po.