Activity Concentrations of Radionuclides in Economic Minerals from Igarra Area, Edo State, Nigeria
The study focuses on assessing the activity concentrations of radionuclides in four economic minerals (dolomite, feldspar, limestone, and calcite) collected from quarry sites in the Igarra area of Edo State, Nigeria. The importance of understanding these concentrations lies in their significance in geosciences and health physics, as primordial radionuclides are the main external source of radiation exposure in soil, rocks, and minerals.
Gamma ray spectrometric technique was employed to analyze the samples. The specific activity concentrations of three radionuclides, namely 226Ra, 232Th, and 40K, were measured in each mineral. For dolomite, the specific activity concentrations ranged from 0.79±0.1 to 4.3±0.24 Bq/kg for 226Ra, 0.27±0.09 to 3.65±0.30 Bq/kg for 232Th, and 27.4±1.91 to 505.19±8.19 Bq/kg for 40K, with respective mean values of 2.88 Bq/kg, 1.61 Bq/kg, and 227.33 Bq/kg. In feldspar, the activity values ranged from 0.69±0.09 to 2.01±0.15 Bq/kg for 226Ra, 0.52±0.11 to 1.06±0.15 Bq/kg for 232Th, and 49.29±2.30 to 248.42±4.99 Bq/kg for 40K, with respective mean values of 1.40 Bq/kg, 0.76 Bq/kg, and 152.28 Bq/kg. For calcite, the activity concentrations ranged from 0.54±0.09 to 10.57±0.41 Bq/kg for 226Ra, 1.28±0.19 to 6.12±0.44 Bq/kg for 232Th, and 81.37±3.32 to 795.16±11.02 Bq/kg for 40K, with respective mean values of 5.54 Bq/kg, 3.81 Bq/kg, and 466.62 Bq/kg. Similarly, in limestone, the activity concentrations ranged from 0.63±0.09 to 3.91±0.22 Bq/kg for 226Ra, 0.67±0.13 to 2.67±0.26 Bq/kg for 232Th, and 57.49±2.60 to 421.39±7.17 Bq/kg for 40K, with respective mean values of 2.05 Bq/kg, 1.59 Bq/kg, and 220.02 Bq/kg.
The mean specific activities of 226Ra, 232Th, and 40K in all four economic minerals were found to be below the world average values recommended by the United Nations Scientific Committee on the Effects of Atomic Radiation, except for calcite’s 40K, which slightly exceeded the recommended value.
Radiation dose assessments were also conducted for each mineral. The computed mean absorbed doses for dolomite, feldspar, calcite, and limestone were below the world average value of 58 nGy/h. The mean annual effective dose equivalent for outdoor (occupational) and indoor (residential) exposures for each mineral was also found to be within acceptable levels.
Furthermore, the mean external hazard index and excess lifetime cancer risk calculations for both residential and occupational exposures to the minerals were below unity and in agreement with the worldwide average value, respectively.
Based on the findings, the use of these economic minerals as aggregate building materials or for domestic purposes does not pose any significant risk to the public regarding radiation protection. Nonetheless, regular radiological monitoring of the economic minerals is recommended to ensure that radiation doses remain as low as reasonably achievable.
EVALUATING THE NATURAL RADIOACTIVITY OF ECONOMIC MINERALS AT QUARRY SITES IN THE IGARA AREA, EDO STATE, NIGERIA. GET MORE, ACTUARIAL SCIENCE PROJECT TOPICS AND MATERIALS