Assessment of effective dose and radiological risk from natural radioactivity in rock samples of Davanagere locality, Karnataka, India.

This paper presents the results of a systematic investigation of the natural radioactivity in rock samples of Davanagere locality, Karnataka, India. The radioactivity in rocks was measured using the NaI(TI) gamma-ray spectrometer. An effort was made to identify the minerals present in rock samples by FTIR spectroscopy. The activity of ²³²Th, ²²⁶Ra and ⁴⁰K radionuclides in rocks vary from 27.96 ± 1.00 to 103.85 ± 1.90, 50.89 ± 1.98 to 135.28 ± 3.15 and 512.46 ± 4.86 to 974.31 ± 7.05 Bq kg⁻¹with a mean value of 59.79 ± 1.45, 85.79 ± 2.54 and 787.03 ± 6.19 Bq kg⁻¹, respectively. Radiological hazard parameters such as radium equivalent activity, external and internal hazard indices absorbed dose rate, ELCR for indoor exposure and annual effective doses for different body organs were estimated. The activity of natural radionuclides were found to be high compared to the national and world average values. However, the hazard indices were found to be within the recommended limits. The Quartz, Calcite and Kaolinite extinction coefficients in rocks ranged from 87.37 to 121.73, 31.43 to 119.14, and 33.10 to 63.97, respectively. The radionuclide activity concentration was found to depend on the kaolinite and calcite minerals. [ABSTRACT FROM AUTHOR]