Radioactivity and hydrochemical properties of certain thermal Turkish spa waters

The study aims to determine the radioactivity levels of thermal waters which have been used seasonally or permanently in spas for therapeutic intentions. Samples were collected from spas in different regions of Turkey. Some radionuclides (K-40, Th-232, Ra-226, Cs-137), gross alpha (GA) and gross beta (GB) activities, and physical and some chemical parameters were measured. Gamma radiation measurements for Ra-226, Th-232 and K-40 radionuclides were performed by using a high purity germanium (HPGe) detector. The results of the gamma spectrometry ranged from 1.385 to 11.025 mBql(-1) for Ra-226, < minimum detectable activity to 3.477 mBql(-1) for 232Th and 9.679 to 36.989 mBql(-1) for K-40. GA and GB activity concentrations were detected by using ultra-low level alpha/beta counter. The GA and GB activity ranged from 43 to 3,182 mBql(-1) and 54 to 1,950 mmBql(-1), respectively. Based on calculated annual effective dose equivalent, the total dose originated mostly from Ra-226 and slightly from K-40. Furthermore, waters with high Cl content were enriched with K-40, Ra-226 isotopes, and the source of GA and GB activity in these waters was mostly Ra-226. Strong high positive correlation between Cl, Ra-226 and total dissolved solids in Cl-enriched samples indicated that the nuclides formed from dissolved minerals in these waters.