Determination and differentiation of 226Ra and 222Rn by gamma-ray spectrometry in drinking water

The analysis of Ra-226 in natural waters can be tedious and time-consuming. For the determination and differentiation of activities of Ra-226 and Rn-222 in drinking water by gamma-ray spectrometry a simple and fast method is presented. Activities of Ra-226 > 0.5 Bq L-1 can be determined according to stabilization of the sample without further procedures. For a more sensitive detection sample volumes of up to 5 litres are applicable by a rapid precipitation procedure without large expenditure. Further laborious enrichment methods are not necessary. Thus, detection limits of 0.1 Bq L-1 can be obtained when using sample volumes of 5 litres. Therefore the method is suitable for the monitoring of radioactivity in drinking water samples in accordance with the legal guidance of the European Union.