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 ( 40 K, 232 Th, 226 Ra, 137 Cs), gross alpha (GA) and gross beta (GB) activities, and physical and some chemical parameters were measured. Gamma radiation measurements for 226 Ra, 232 Th and 40 K 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 226 Ra, <minimum detectable activity to 3.477 Bql -1 for 232 Th and 9.679 to 36.989 Bql -1 for 40 K. 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 226 Ra and slightly from 40 K. Furthermore, waters with high Cl content were enriched with 40 K, 226 Ra isotopes, and the source of GA and GB activity in these waters was mostly 226 Ra. Strong high positive correlation between Cl, 226 Ra and total dissolved solids in Cl-enriched samples indicated that the nuclides formed from dissolved minerals in these waters.