BfS commissions evaluation of current data on radioactivity in drinking water

From 2020 to 2022 the BfS has been commissioning research into how the levels of radioactive substances of natural origin that occur in drinking water in Germany vary on a regional and seasonal scale.

Overall, the radioactive contamination of drinking water in Germany is considered to be low. However, the Federal Office for Radiation Protection (BfS) has commissioned a new research project in order to examine, on behalf of the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU), whether special protective measures are called for due to exceptions in certain regions. This evaluation will entail a specific examination of current data and will provide the BfS with insights into how various rock formations and their radionuclide content affect water quality and ultimately influence the resulting radiation exposure.

BfS President Inge Paulini said: "Clean drinking water is a valuable commodity. Thankfully, the quality of our drinking water in Germany is so good that we can generally drink or use it straight from the tap without hesitation. To be on the safe side, we want to obtain further information about the distribution of radionuclides in drinking water, as this can vary depending on the region's geological composition. With this in mind, we're taking a closer look at the latest data."

GRS to evaluate data from 15,000 water supply facilities

Water reservoir Source: © Joachim Donath

On behalf of the BfS, the organisation Gesellschaft für Anlagen- und Reaktorsicherheit (GRS) will retrieve and evaluate the data from around 15,000 water supply facilities. The analysis follows on from previous studies and initiatives by the BfS in relation to drinking-water quality and aims to provide an even better overview of the distribution of radioactive substances in drinking water in Germany. It relates exclusively to radionuclides of natural origin, as legal requirements already ensure the comprehensive monitoring of artificial radionuclides. The results are expected in 2022.

Depending on the local geology, all rocks and soils contain some level of natural radionuclides, which can enter surface water and groundwater by way of complex dissolution processes. Chief among these radionuclides are the decay products of the uranium-238, uranium-235 and thorium-232 series. As concluded by a BfS study in 2009, the level of contamination by these natural radionuclides in drinking water in Germany can generally be classified as low. The study showed that, on average, adults are exposed to some 0.009 millisieverts of radiation per year due to radionuclides in drinking water. In comparison, the average natural radiation dose received by a member of the general public is approximately 2.1 millisieverts per year.

Research findings to underpin recommendations

Nonetheless, the study revealed a considerable range of variation in the concentrations of natural radionuclides in drinking water. Now, the intention is to expand upon the results of the BfS study in 2009. With the research findings relating to the spatial and temporal distribution of radionuclides in drinking water, it will be easier for the water companies and relevant authorities to obtain an overview of the situation and, if necessary, to use this overview to derive recommendations aimed at protecting the population.

The analysis will be based on data that the water distribution companies were required to collect by the end of 2019 in the context of the revised Drinking Water Ordinance (TrinkwV). Prior to this, at the instigation of the BMU, the BfS worked with experts from federal states and associations to draw up corresponding criteria and to compile these criteria in a guide published by the BMU.