In order to assess the levels of natural radioactivity and the associated radiological hazards in some building materials of the Mayo-Kebbi region (Chad), a total of nineteen samples were collected on the field. Using a high resolution γ-ray spectrometry system, the activity concentrations of radium (226Ra), thorium (232Th) and potassium (40K) in these samples have been determined. The measured average activity concentrations range from 0.56 ± 0.37 Bq kg−1 to 435 ± 7 Bq kg−1, 1.3 ± 0.6 Bq kg−1 to 50.6 ± 1.1 Bq kg−1 and 4.3 ± 2.0 Bq kg−1 to 840 ± 9 Bq kg−1, for 226Ra, 232Th and 40K, respectively. The highest 226Ra average activities is found in soil brick samples of Zabili. The highest mean value of 232Th and 40K concentrations are found in soil brick samples of Madajang. The activity concentration and the radium equivalent activity (Raeq) have been compared to other studies done elsewhere in the world. Their average values are lower than most of those of countries with which the comparison has been made. Were also evaluated, the external radiation hazard index, the internal radiation hazard index, the indoor air absorbed dose rate, the outdoor air absorbed dose rate, the activity utilization index, the annual effective dose, the annual gonadal dose equivalent, the representative level index, as well as, the excess lifetime cancer risk. In accordance with the criterion of the Organization for Economic Cooperation and Development, our results show that soil brick samples of Zabili and Madajang increases the risk of radiation exposure, thereby the possibility of developing cancer by people living in this environment. Based on these findings, brick samples from Zabili and Madajang are not recommended for construction purposes. All other sample materials have properties that are acceptable for use as building materials in terms of radiation hazard.
The main objective of this study is to assess the level of heavy metals pollution in soil samples collected around gold mines located in Betaré Oya (BO) and Batouri (BA) in Eastern Cameroon. Elemental analysis of soil samples was carried out using Quant´X EDXRF spectrometer. Its sensitivity and accuracy were increased by using the Fundamental Parameter approach for quantification of the results. Analysis results showed high content of iron (39300±200 ppm), the presence of manganese (730±70 ppm), arsenic (4±2 ppm), zirconium (314±4 ppm) and lead (79±9 ppm) as compared to worldwide average upper continental crust (UCC). The mean Enrichment Factors (EF) decrease as Pb>As>Zr>Mn>Fe>Y>Ga>Zn>Cu>Ni> Rb>Sr>Sn>Ba in agreement with the Contamination Factors (CF). The values of pollution load index (PLI) were found to be low in all the studied samples and indicate that the studied sites in Bétaré Oya and Batouri are in low pollution status regarding the total of the studied metals. Results of this study pointed out that soils examined in the gold mining areas of Eastern Cameroon are polluted by heavy metals. It is therefore important that measures should be geared towards strengthening the monitoring of mining areas to stem down the level of contamination of soil. Phytoremediation of sites after closing open pits or the biogeosystem method would be a suitable way of regulation of the studies areas.
PAMELA is a satellite borne experiment designed to study with great accuracy cosmic rays of galactic, solar, and trapped nature in a wide energy range (protons: 80 MeV-700 GeV, electrons 50 MeV-400 GeV).
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