The geology of Magaoni area is associated with the presence of heavy minerals [1]. Magaoni’s neighbours Maumba and Nguluku where ilmenite was discovered by Tiomin Resource Inc. in 1996, using drilling and chemical an...The geology of Magaoni area is associated with the presence of heavy minerals [1]. Magaoni’s neighbours Maumba and Nguluku where ilmenite was discovered by Tiomin Resource Inc. in 1996, using drilling and chemical analysis [2]. Ilmenite mineral is known to be magnetically weak, but provides observable magnetic response [3]. In this study, ground magnetic survey method was carried out to map magnetic anomalies of established stations, associated with ilmenite bearing formations. The magnetic contour map plotted showed weak and shallow magnetic signatures spread throughout the study area. 2D Euler deconvolution solutions revealed presence of magnetised formations from near surface to a maximum depth of about 450 m at some points. The weak magnetic formations of near surface indicated presence of ilmenite. Energy dispersive X-ray spectroscopy was done on soil samples collected randomly from the study area to determine the percentage of iron and titanium oxides. The results showed elevated values of titanium dioxide, ranging from 1.5% to 13% which is way above the global average of about 0.7% [4]. The percentage of iron oxide was low, ranging from 1.5% to 4%, this being the reason for weak magnetisation of the study area.展开更多
The main aim of investigating activity concentrations together with distribution of radionuclides naturally in soil from Kargi was to evaluate radiological health hazard together with environmental radioactivity. Rese...The main aim of investigating activity concentrations together with distribution of radionuclides naturally in soil from Kargi was to evaluate radiological health hazard together with environmental radioactivity. Research shows radionuclides as one source of exposure due to radiation with detrimental effects health wise for populations found in areas considered high background radiation. After collecting 117 soil samples from the area, analysis was done in order to measure their natural radioactivities due to <sup>40</sup>K, <sup>232</sup>Th and <sup>226</sup>Ra radionuclides. Measurements method of gamma spectrometry employing a high purity germanium (HPGe) detector was employed basically to evaluate the radiological hazard of radioactivities. For <sup>40</sup>K, <sup>232</sup>Th and <sup>226</sup>Ra, mean calculated activities were 353.19 ± 110.07, 7.98 ± 3.98 and 7.37 ± 2.60 Bq<span style="white-space:nowrap;">·</span>kg <sup>-1</sup> respectively. Mean values of absorbed and effective dose rates, external and internal hazard indices together with radium equivalent activity were 23.82 ± 6.59 nGy<span style="white-space:nowrap;">·</span>h <sup>-1</sup> and 0.14 ± 0.04 mSv<span style="white-space:nowrap;">·</span>y <sup>-1</sup>, 0.12 ± 0.03 and 0.14 ± 0.04 and 45.90 ± 12.65 Bq<span style="white-space:nowrap;">·</span>kg <sup>-1</sup> respectively. Comparing with approved global values, the values were found to be below the given global limits. Evidence of involvement of metasomatic activity of the radioelements or fractionation during weathering is seen as calculations give a higher value Th/U. Excess cancer risk, calculated from the samples showed lower values as compared to global standard values hence minimal chance of getting cancer disease. The area is safe from cancer causing radionuclides.展开更多
文摘The geology of Magaoni area is associated with the presence of heavy minerals [1]. Magaoni’s neighbours Maumba and Nguluku where ilmenite was discovered by Tiomin Resource Inc. in 1996, using drilling and chemical analysis [2]. Ilmenite mineral is known to be magnetically weak, but provides observable magnetic response [3]. In this study, ground magnetic survey method was carried out to map magnetic anomalies of established stations, associated with ilmenite bearing formations. The magnetic contour map plotted showed weak and shallow magnetic signatures spread throughout the study area. 2D Euler deconvolution solutions revealed presence of magnetised formations from near surface to a maximum depth of about 450 m at some points. The weak magnetic formations of near surface indicated presence of ilmenite. Energy dispersive X-ray spectroscopy was done on soil samples collected randomly from the study area to determine the percentage of iron and titanium oxides. The results showed elevated values of titanium dioxide, ranging from 1.5% to 13% which is way above the global average of about 0.7% [4]. The percentage of iron oxide was low, ranging from 1.5% to 4%, this being the reason for weak magnetisation of the study area.
文摘The main aim of investigating activity concentrations together with distribution of radionuclides naturally in soil from Kargi was to evaluate radiological health hazard together with environmental radioactivity. Research shows radionuclides as one source of exposure due to radiation with detrimental effects health wise for populations found in areas considered high background radiation. After collecting 117 soil samples from the area, analysis was done in order to measure their natural radioactivities due to <sup>40</sup>K, <sup>232</sup>Th and <sup>226</sup>Ra radionuclides. Measurements method of gamma spectrometry employing a high purity germanium (HPGe) detector was employed basically to evaluate the radiological hazard of radioactivities. For <sup>40</sup>K, <sup>232</sup>Th and <sup>226</sup>Ra, mean calculated activities were 353.19 ± 110.07, 7.98 ± 3.98 and 7.37 ± 2.60 Bq<span style="white-space:nowrap;">·</span>kg <sup>-1</sup> respectively. Mean values of absorbed and effective dose rates, external and internal hazard indices together with radium equivalent activity were 23.82 ± 6.59 nGy<span style="white-space:nowrap;">·</span>h <sup>-1</sup> and 0.14 ± 0.04 mSv<span style="white-space:nowrap;">·</span>y <sup>-1</sup>, 0.12 ± 0.03 and 0.14 ± 0.04 and 45.90 ± 12.65 Bq<span style="white-space:nowrap;">·</span>kg <sup>-1</sup> respectively. Comparing with approved global values, the values were found to be below the given global limits. Evidence of involvement of metasomatic activity of the radioelements or fractionation during weathering is seen as calculations give a higher value Th/U. Excess cancer risk, calculated from the samples showed lower values as compared to global standard values hence minimal chance of getting cancer disease. The area is safe from cancer causing radionuclides.
