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Radioactivity Concentration Level of 238U, 232Th, and 40K in Soil Samples of some Abandon Mining Sites in Nasarawa, Nasarawa State, Nigeria |
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PP: 59-68 |
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doi:10.18576/jrna/090110
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Author(s) |
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Idris M. Mustapha,
Sidi, M. Aliyu,
Obiri G. Okara,
Ibrahim A. Mohammad,
Umar Adamu,
Abdullahi A. Aisha,
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Abstract |
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| A comprehensive study was conducted to determine the radioactivity concentration level in soil samples of some abandon mining sites in Nasarawa, Nasarawa State using sodium iodide-doped thallium gamma spectrometer. A total of ten soil samples were collected each from different locations in the study area. The soil samples were air-dried, sieved, and sealed in a plastic container. The samples were then analyzed using NaI(Tl) detector for γ-ray spectral measurements. The mean activity concentration of 238U, 232Th and 40K in the samples are 5.66 ± 1.291 BqKg-1, 0.904 ±0.09BqKg-1 and 277.62±21.6BqKg-1 respectively. The concentration of 232U and 232Th in all the samples is lower than the word average of 30 Bq/kg and 35 Bq/kg respectively as recommended by regulatory bodies. The concentration of 40K in S6, S8, and S9 is higher than the average standard of 400 Bq/kg as recommended by regulatory bodies. The absorbed dose rate, radium equivalent, external hazard indices, annual effective dose equivalent, are in the range (mean) of 1.070-29.37 nGy/h (14.74 nGy/h), 2.251- 55.63 Bq/kg (28.33 Bq/kg), 0.006- 0.0765 mSv/yr (0.1502 mSv/yr), 0.005-0.144 mSv/yr (0.072 mSv/yr), and 0.0018-0.504 µSv/yr (0.253 µSv/yr) respectively. The absorbed dose rate for the entire locations are lower than the average standard of 55 Bq/kg set by regulatory bodies. The radium equivalent activity for all locations is lower than the average standard of 370 Bq/kg as recommended by regulatory bodies. Similarly, the calculated external hazard index for all the sample is lower than the average standard of 1 Bq/kg recommended. The calculated annual effective dose equivalent for all the sample is lower than the recommended standard of 1 mSv/yr for public exposure. The calculated excess lifetime cancer risk in S6, S7, S8, S9, and S10 samples were higher than the acceptable safe limit of 0.29 x 10-3 recommended by regulatory bodies. |
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