Measurements of Natural Radioactivity Levels in the Soil, Coffee and Zuwaye Lake Water Samples Collected from the Selected Area, in Ethiopia, by Using Gamma Ray Spectroscopy.
| dc.contributor.author | Aliyi, Rukiya | |
| dc.date.accessioned | 2020-09-21T06:14:40Z | |
| dc.date.accessioned | 2023-11-09T11:26:26Z | |
| dc.date.available | 2020-09-21T06:14:40Z | |
| dc.date.available | 2023-11-09T11:26:26Z | |
| dc.date.issued | 2020-06-06 | |
| dc.description.abstract | People are exposed to radioactivity in soil, plant and even in other environment that is raised from uranium, thorium and potassium-40 radionuclides. Environmental radioactivity and the associated external exposure due to gamma radiations depend primarily on the geological, geographical and human activities. In this study the activity concentration of 238U, 232Th and 40K radionuclides were determined in 12 soil samples, Four coffee samples and Four Zuwaye lake water samples collected from some parts West-Arsi Zone, Shashemane and Zuwaye, Ethiopia using High Pure Germanium Detector (HPGe). The average activity concentration of 238U, 232Th and40K in the soil samples was 45.83, 100.525, 845.65Bq/Kg, respectively. These values were higher than the average world recommended values for 238U , 232Th , 40K , respectively which are 35, 30 and 400 Bq/Kg for 238U , 232Th , 40K respectively [UNSCEAR, 2000]. During our experimental activities our detector could identify only potassium-40 in the coffee samples. All coffee samples had 591.185 Bq/Kg average values of 40K concentrations that were higher than the acceptable value (412 Bq/kg) [UNSCEAR, 2010]. Activity concentration of 238U in Lake Zuwaye Water was vary from 2.94±0.25 Bq/L to 3.02±0.27 Bq/L with an average value of 2.99±0.267 Bq/L, 232Th was vary from 6.9±0.73 Bq/L to 8.39±0.82 Bq/L also with an average value of 7.5 ±0.76 Bq/L and the activity concentration of 40K varies from 98.12 4.16154 to 101.99 4.91556 with an average value 99.77±4.80Bq/L. The activity concentration from the studied areas were found to be below WHO guidelines of 10 Bq/L for 238U and higher than 1 Bq/L for 232Th. The World Health Organization recommended level of 40K in water meant for drinking is unavailable. The values of radium equivalent for different soil samples in area under investigated were ranged from 124.96 to 330.7 Bq/kg with average value 248.75Bq/kg which is lower than the recommended maximum value 370 Bq/kg [Gilmore, G.R.,2008]. The calculated values of Dr were found to vary from 96.64 to 191.02nGy h-1, with an average value of 149.5117nGy h-1. The measured average absorbed dose rate in the air and the measured vii | average value of the representative level index are higher than the recommended international levels of 55 nGy h-1. Such locations are not safe for human residency and agriculture. The calculated values for Dout, Din, and Dtot respectively 0.185, 1.035, and 1.22 mSv/year to global measured values, these values were all higher than the assigned worldwide values of 0.08, 0.42, and 0.5 year-1, respectively [UNSCEAR,2000]. The locations from which the soil samples collected were all not safe according to the Radiation Protection, and such locations cannot be classified as hazard free. The external hazard index (Hex) and internal hazard index (Hin) due to the emitted -rays of the soil samples were calculated according to the following criterion: The value of Hex must be lower than unity in order to keep the radiation hazard insignificant. The calculated external hazard index values were found to vary between 0.43 and 0.78 with average value of 0.668 these values are less than unity, which is 33.2 % less than world recommended value. The calculated internal hazard index values were found to vary between 0.5 and 0.93 with average value of 0.79, which is 11.0% less than world recommended value [Dabayneh K et al,.2008]. Radioactivity level index vary from 1.19 to 2.395 Bq/Kg with average values is 1.917 Bq/Kg. The average value of Radioactivity level index is higher than the recommended safe limit ≤ 1 [Thabayneh K, Jazzar M.2012]. Therefore, the soils have radiation hazard and are harmful to society living there. The values of radium equivalent for different coffee samples in study area were vary from 42.5 to 54.92 Bq/Kg with average value 47.44Bq/Kg which is lower than the world recommended maximum value 370 Bq/Kg [Gilmore, 2008]. The determined values of absorbed dose rate (Dr) were found to vary from 23.73 to 30.67nGy h- 1, with an average value of 26.49nGy h-1. The measured average absorbed dose rate in the air was lower than the recommended international levels of 55 nGy h-1[Turner J et al., 2007] and the coffee was safe for use. The determined average values for Dout, Din, and Dtot respectively 0.0325, 0.181, and 0.107 mSv /year to global measured values, these values were all lower than the worldwide values of 0.08, 0.42, and 0.50 mSvyear-1, respectively [UNSCEAR, 2000]. viii | The external (Hex) and internal (Hin) hazard index due to the emitted -rays of the coffee samples were calculated and examined according to the following criterion: The value of Hex must be lower than unity in order to keep the radiation hazard insignificant. This is the radiation exposure due to the radioactivity from a construction material, limited to 1.5 mGy•y−1. The maximum values of Hex equal to unity correspond to the upper limit of Raeq (370 Bq/Kg) [48]. The calculated external hazard index values were found to vary between 0.115 and 0.148 with average value of 0.128 these values are less than unity, which is 87.2 % less than world recommended value. The calculated internal hazard index values were found to vary between 0.115 and 0.148 with average value of 0.128, which is 87.2% less than world recommended value [Knoll G.F, 2000]. Radioactivity level index to vary between 0.36 to 0.475 Bq/Kg with average value is 0.4 Bq/Kg. The average value of Radioactivity level index is lower than one the recommended safe limit ≤ 1 [Van Rooyen T.J., 2002]. Therefore, the coffee had no health radiation hazard. Hence it can be concluded that the radionuclide concentration of measured coffee samples poses no radiological health hazard to the community. The annual effective dose calculated for the Zuwaye lake Water was varied from 0.081 to 0.09 mSv/y with an average of 0.086 mSv/y. This value, when compared with the ICPR standard value of 1mSvyr-1 is very low, hence, it can be concluded that the radionuclide concentration of Zuwaye Lake water is negligible and poses no radiological health hazard to the community. | en_US |
| dc.identifier.uri | http://10.90.10.223:4000/handle/123456789/22383 | |
| dc.language.iso | en | en_US |
| dc.publisher | Addis Ababa University | en_US |
| dc.subject | Measurements | en_US |
| dc.subject | Natural Radioactivity Levels | en_US |
| dc.subject | Soil | en_US |
| dc.subject | Coffee and Zuwaye Lake | en_US |
| dc.subject | Water Samples Collected | en_US |
| dc.subject | Selected Area | en_US |
| dc.subject | Ethiopia | en_US |
| dc.subject | Using Gamma Ray Spectroscopy | en_US |
| dc.title | Measurements of Natural Radioactivity Levels in the Soil, Coffee and Zuwaye Lake Water Samples Collected from the Selected Area, in Ethiopia, by Using Gamma Ray Spectroscopy. | en_US |
| dc.type | Thesis | en_US |