Determination of 226Ra, 224Ra, 223Ra and 228Ra in mineral water samples of the Slovak Republic

Abstract

The Slovak Republic is very rich in mineral water sources. In recent years, it has been discovered that a number of mineral waters in the Slovak Republic contain high levels of 226Ra and 228Ra. Moreover, there is a lack of information on 224Ra and 223Ra concentrations in mineral waters as well. The currently approved techniques for alpha emitting radium isotopes are based on radon emanation methods. Due to the long ingrowth periods required by these techniques, any 224Ra and 223Ra in the sample decay away and go undetected. For this reason, we have used an alpha spectrometric method for the simultaneous determination of 226Ra, 223Ra and 224Ra. Radium was concentrated by a lead sulphate co-precipitation. The precipitate was dissolved in EDTA and the radium isotopes were separated from possible interfering radionuclides using barium sulphate micro precipitation. The radium-barium precipitate was filtered and counted by alpha spectrometry. 133Ba was used to quantify the yield by gamma spectrometry. In our laboratory, gamma spectrometry was also used for the determination of 228Ra in mineral water samples. Radium was concentrated by a lead-barium sulphate co-precipitation. 133Ba was used to quantify the yield, found to be 97 % on the average, by gamma spectrometry. Furthermore, the committed effective doses for 226Ra, 224Ra, 223Ra, 228Ra intake via ingestion of mineral waters for the members of public were calculated.