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 (⁴⁰K, ²³²Th, ²²⁶Ra, ¹³⁷Cs), gross alpha (GA) and gross beta (GB) activities, and physical and some chemical parameters were measured. Gamma radiation measurements for ²²⁶Ra, ²³²Th and ⁴⁰K radionuclides were performed by using a high purity germanium (HPGe) detector. The results of the gamma spectrometry ranged from 1.385 to 11.025 Bql⁻¹ for ²²⁶Ra, <minimum detectable activity to 3.477 Bql⁻¹ for ²³²Th and 9.679 to 36.989 Bql⁻¹ for ⁴⁰K. GA and GB activity concentrations were detected by using ultra-low level α/β counter. The GA and GB activity ranged from 43 to 3,182 mBql⁻¹ and 54 to 1,950 mBql⁻¹, respectively. Based on calculated annual effective dose equivalent, the total dose originated mostly from ²²⁶Ra and slightly from ⁴⁰K. Furthermore, waters with high Cl content were enriched with ⁴⁰K, ²²⁶Ra isotopes, and the source of GA and GB activity in these waters was mostly ²²⁶Ra. Strong high positive correlation between Cl, ²²⁶Ra and total dissolved solids in Cl-enriched samples indicated that the nuclides formed from dissolved minerals in these waters.