Determination of natural radioactivity in the soil of Omaruru, Namibia
| dc.contributor.author | Mbuende, Mercey | |
| dc.date.accessioned | 2022-09-23T13:42:07Z | |
| dc.date.available | 2022-09-23T13:42:07Z | |
| dc.date.issued | 2022 | |
| dc.description | A mini thesis submitted in partial fulfillment of the requirements for the Degree of Master of Science (Nuclear Science) | en_US |
| dc.description.abstract | In this study, the level of natural radioactivity and associated hazards has been evaluated for 50 soil samples from the town of Omaruru in western Namibia. Activity concentrations (Bqkg-1) of the primordial radionuclides 238U, 232Th and 40K in these soil samples were determined using a gamma-ray spectroscopy system with a High Purity Germanium detector (HPGe). These activity concentrations of the primordial radionuclides were calculated by using the intensities of selected gamma lines in the spectra as emitted by the radionuclides. The samples were collected from ten geographical areas which are inhabited localities in the town. The obtained results of activity concentrations for every soil sample was compared with the worldwide average values as recommended by UNSCEAR 2000. The values of activity concentration of 238U have been found to lie in the range of 39.4 - 111.1 Bq kg-1, with an average value of 63.9 ± 15.4 Bq kg-1, the values of activity concentration of 232Th ranged from 49.5 - 231.7 Bq kg-1 with an average value of 120.0 ± 42.9 Bq kg-1 and the values of activity concentration of 40K ranged from 692.4 - 1425.5 Bq kg-1, with an average value of 1136.7 ± 197.8 Bq kg-1 . The absorbed dose rates and annual effective dose as well as the radiation hazard indices in the soil samples, were calculated by employing the determined activity concentration values of 238U, 232Th and 40K. The total absorbed dose rate varied from 90.9 to 230.2 nGyh-1, with the average value of 149.4 ± 35.2 nGyh-1 and subsequently the annual effective dose ranged between 0.112 to 0.282 mSvy -1, with an average value of 0.183 ± 0.043 mSvy-1. This result of the annual effective dose is much lower than the recommended maximum permissible dose rate of 1.0 mSvy-1. The implication thereof is that the town of Omaruru has a normal background radiation. Additionally, the average value of the radium equivalent activity was 323.0 ± 80.2 Bq kg-1, and is lower than the recommended maximum value of 370 Bq kg-1. Furthermore, the average external hazard index, which was 0.87 ± 0.22, is also below the recommended safe level of 1. Based on these results, the radiological hazard is low in Omaruru. The results obtained in this study would be useful in establishing a baseline data to serve as a future reference in confirming possible changes in the environmental radioactivity as a result of any nuclear and related activities. | en_US |
| dc.identifier.uri | http://hdl.handle.net/11070/3261 | |
| dc.language.iso | en | en_US |
| dc.publisher | University of Namibia | en_US |
| dc.subject | Radiation | en_US |
| dc.subject | Hazard | en_US |
| dc.subject | Soil in Namibia | en_US |
| dc.title | Determination of natural radioactivity in the soil of Omaruru, Namibia | en_US |
| dc.type | Thesis | en_US |