Measurement of activity concentration of natural radionuclides for the assessment of radiological indices.

The concentration of natural radionuclides ((226)Ra, (232)Th and (40)K) in the soil samples were determined for 28 locations in Kanyakumari district of southwest India by means of gamma spectroscopy with NaI (Tl) detector. The mean activity concentrations for (232)Th and (40)K are greater than the world average values reported by United Nations Scientific Committee on Effects of Atomic Radiation for areas of normal background radiation. Radiological indices were estimated for the radiation of the natural radioactivity of all soil samples. Estimated mean total absorbed dose in air from activity concentration of (226)Ra, (232)Th and (40)K in high background radiation areas (HBRAs) is 200 + or - 30 nGy h(-1) and in low background radiation areas (LBRAs) is 29 + or - 14 nGy h(-1). Annual outdoor effective dose was also calculated for HBRA and LBRA. Also the representative level index, which resulted from the natural radionuclides in the soil samples were also estimated and given.