Assessment of terrestrial naturally occurring radioactive Material in soil and mine tailings of Awo and Ede, Osun-State, Nigeria.
The levels of natural radioactivity of 40K, 238U and 232Th in soils and mine tailings of Awo and Ede areas of Osunstate, Nigeria have been measured using a portable, advanced survey meter 992 Fluke Victoreen Gamma Scout Model for in-situ investigation and a 1 inch by 1 inch Cesium Iodide detector system. The specific activities of 40K varied from 316.67±14.23 Bq kg-1 to 1487.35±3.03 Bq kg-1 with a mean value of 620.05±9.57 Bq kg-1 ; for 238U, 13.11±2.36 Bq kg-1 to 88.26±3.03 Bq kg-1 with a mean value of 27.50±3.14 Bq kg-1 ; and for 232Th, 9.26±1.00 Bq kg-1 to 55.81±2.99 Bq kg-1 with a mean value of 18.26±2.17 Bq kg-1. The mean values obtained for Absorbed Dose rate and External Hazard Index (Hex) were 48.12 nGyhr-1 and 0.26 respectively. Generally, with the exception of 40K, the activity levels of the radionuclide investigated were low and within the world average values. The calculated hazard indices were lower than internationally recommended limits.
Keywords: Mining, NORMs, Hazards, Gamma Spectrometry