en Radiation Biology Radiation Biology تحقيق بديع Original Research <div style="text-align: justify;"><span style="font-size:10pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="color:black"><span lang="en-US" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="color:#1f497d"><span style="font-style:italic"><span style="font-weight:bold"><span style="language:en-US">Background</span></span></span></span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="color:#1f497d"><span style="font-weight:bold"><span style="language:en-US">:</span></span></span></span></span></span> <span lang="en-US" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">Most parts of the Erongo region of Namibia have shown high background radiation. The aim and objective of this study is to determine the natural radioactivity levels and evaluate the radiological hazards in Usakos marble dome in the Erongo region. </span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="color:#1f497d"><span style="font-style:italic"><span style="font-weight:bold"><span style="language:en-US">Materials and Methods</span></span></span></span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="color:#1f497d"><span style="font-weight:bold"><span style="language:en-US">:</span></span></span></span></span></span> <span lang="en-US" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">A high purity germanium (HPGe) detector was used in this study to measure the activity concentrations </span></span></span></span><span lang="en-US" style="font-size:5.9939pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">²²⁶</span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">Ra, </span></span></span></span><span lang="en-US" style="font-size:5.9939pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">²³²</span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">Th, and </span></span></span></span><span lang="en-US" style="font-size:5.9939pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">⁴⁰</span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">K in marble samples from 20 different points in Usakos marble dome in the Erongo region, Namibia. </span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="color:#1f497d"><span style="font-style:italic"><span style="font-weight:bold"><span style="language:en-US">Result</span></span></span></span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="color:#1f497d"><span style="font-weight:bold"><span style="language:en-US">:</span></span></span></span></span></span> <span lang="en-US" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">The mean activity concentrations were found in the range of 0.37 to 339.60 Bq kg</span></span></span></span><span lang="en-US" style="font-size:5.9939pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">^-1</span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US"> for </span></span></span></span><span lang="en-US" style="font-size:5.9939pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">²²⁶</span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">Ra, 0.20 to 210.30 Bq kg</span></span></span></span><span lang="en-US" style="font-size:5.9939pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">^-1</span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US"> for </span></span></span></span><span lang="en-US" style="font-size:5.9939pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">²³²</span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">Th, and 2.96 to 928.70 Bq kg</span></span></span></span><span lang="en-US" style="font-size:5.9939pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">^-1</span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US"> for </span></span></span></span><span lang="en-US" style="font-size:5.9939pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">⁴⁰</span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">K, respectively. The activity concentrations of </span></span></span></span><span lang="en-US" style="font-size:5.9939pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">²²⁶</span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">Ra, </span></span></span></span><span lang="en-US" style="font-size:5.9939pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">²³²</span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">Th, and </span></span></span></span><span lang="en-US" style="font-size:5.9939pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">⁴⁰</span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">K were used to estimate values of radium equivalent activity (Ra</span></span></span></span><span lang="en-US" style="font-size:5.9939pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">_eq</span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">), Absorbed dose rate (Dr), internal and external hazard indices (H</span></span></span></span><span lang="en-US" style="font-size:5.9939pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">_ex</span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US"> & H</span></span></span></span><span lang="en-US" style="font-size:5.9939pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">_in</span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">) and the activity utilization index (I</span></span></span></span><span lang="el" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Cambria"><span style="language:el">&gamma;</span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">). The calculated mean values were Ra</span></span></span></span><span lang="en-US" style="font-size:5.9939pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">_eq</span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US"> (226.75 Bq kg</span></span></span></span><span lang="en-US" style="font-size:5.9939pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">^-1</span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">), (Dr) (102.99 nGyh</span></span></span></span><span lang="en-US" style="font-size:5.9939pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">^-1</span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">), H</span></span></span></span><span lang="en-US" style="font-size:5.9939pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">_ex</span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">(0.61), H</span></span></span></span><span lang="en-US" style="font-size:5.9939pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">_in</span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US"> (0.95) and I</span></span></span></span><span lang="el" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Cambria"><span style="language:el">&gamma;</span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US"> (1.59). </span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="color:#1f497d"><span style="font-style:italic"><span style="font-weight:bold"><span style="language:en-US">Conclusion</span></span></span></span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="color:#1f497d"><span style="font-weight:bold"><span style="language:en-US">:</span></span></span></span></span></span> <span lang="en-US" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">From a radiological point, the results of (Dr) and (I</span></span></span></span><span lang="el" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Cambria"><span style="language:el">&gamma;</span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">) were found above the world recommended average and the performed correlation analysis showed strong positive correlation amongst </span></span></span></span><span lang="en-US" style="font-size:5.9939pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">²³²</span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">Th and </span></span></span></span><span lang="en-US" style="font-size:5.9939pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">²²⁶</span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="line-height:119%"><span style="font-family:Calibri"><span style="language:en-US">Ra, which confirms these radionuclides as the main contributors to gamma radiation in the Usakos marble dome. The high activity concentrations at some sampling points higher than the world average value pose possible radiological hazards for the marble samples usage for building materials.</span></span></span></span></span></span></span></span></div> Natural radioactivity, radiological hazards, marble, Usakos, Erongo. 403 409 http://ijrr.com/browse.php?a_code=A-10-1-923&slc_lang=en&sid=1 S.A. Onjefu sonjefu@nust.na 7900319475328460021644 7900319475328460021644 Yes Department of Natural and Applied Sciences, Faculty of Health and Applied Sciences, Namibia University of Science and Technology, Windhoek, Namibia N.N. Johannes 7900319475328460021645 7900319475328460021645 No Department of Natural and Applied Sciences, Faculty of Health and Applied Sciences, Namibia University of Science and Technology, Windhoek, Namibia J. Abah 7900319475328460021646 7900319475328460021646 No Department of Mathematics, Science and Sport Education, Faculty of Education, University of Namibia, Katima Mulilo Campus, Namibia L.A. Onjefu 7900319475328460021647 7900319475328460021647 No Department of Civil and Environmental Engineering, Faculty of Engineering, Namibia University of Science and Technology, Windhoek, Namibia. S. Mwiya 7900319475328460021648 7900319475328460021648 No Foresight Group Namibia, P.O. Box 1839, Windhoek, Namibia