Determination of radon-222 and radium-226 in mineral water and drinking water–a survey in Austria

Abstract

A very simple and time saving liquid scintillation counting method that avoids the need for any chemical separation has been developed for the determination of both ²²²Rn and ²²⁶Ra in water. This method takes advantage of the very low background level of the liquid scintillation counter “Quantulus” and of spectral control. The method is very sensitive and specific for the above radionuclides. The lower limit of detection is well below maximum contaminant levels set even by the most strict regulations. In a pilot project for a first surveillance of the drinking water in Austria it was shown that the proposed method was suitable for large scale surveillance and routine analysis. Its application to mineral waters sold in Austria showed elevated levels of ²²⁶Ra in some brands and one exceeded the maximum permissible level by a factor of 20. Considerable concentrations of ²²²Rn were found in drinking waters from certain areas, but no ²²⁶Ra concentrations higher than the lower limit of detection (1.3 pCi l^–1)(48.1 mBq l^–1) were found. Future work to improve the method further and to apply it to large scale surveillance is discussed.