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

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.