Radioactivity concentrations and dose assessments of therapeutic peloids from some Turkish spas

The activity concentrations of natural radionuclides in peloids were studied to assess the radiologic hazard from 18 Turkish spas. The peloids are mainly used for therapeutic treatments, rheumatic diseases and aesthetic purposes. The concentrations of the natural radionuclides Ra-226, Th-232, K-40 and Cs-137 were determined with a gamma ray spectrometer using a HPGe detector. The average activity concentrations of Ra-226, Th-232, K-40, and Cs-137 in the peloids studied were 110.69, 71.52, 576.48 and 0.447 Bq/kg, respectively. The radium equivalent activities in the peloid samples ranged from 63.3 to 766.77 Bq/kg. The absorbed dose rate (D-out) varied between 37.52 and 330.67 nGy/h and most of the observed spa doses are greater than the worldwide recommended values. The annual effective dose values range from 0.26 to 2.78 mu Sv/y. The annual gonadal dose equivalents of the samples vary from 224.07 to 2283.55 with a mean of 821.99 mu Sv/y.