Blessing Okeoghene Ijabor; Akintayo Daniel Omojola; Augustine Onyema Nwabuoku; Funmilayo Ruth Omojola
Abstract
The study is aimed at measuring the outdoor background ionizing radiation (BIR), the absorbed dose rate (ADR), the annual effective dose (AED) and excessive lifetime cancer risk (ELCR) at four sites in the Aniocha South local government area (LGA) of Delta State, denoted as A-D. The study was performed ...
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The study is aimed at measuring the outdoor background ionizing radiation (BIR), the absorbed dose rate (ADR), the annual effective dose (AED) and excessive lifetime cancer risk (ELCR) at four sites in the Aniocha South local government area (LGA) of Delta State, denoted as A-D. The study was performed using a calibrated Geiger-Muller (GM) detector (Radiation Alert Inspector) as well as a geographic positioning system (GPS) to determine the longitude and latitude of each site. The average (range) outdoor BIR, ADR, and AED were 0.021±0.01 (0.01-0.04) mR/hr, 181.6±77.7 (60.9-322.8) nGy/hr, and 0.22±0.10 (0.07-0.40) mSv/yr, respectively. Among the processing sites, the average AED for granite, bitumen, and staff residential areas were 0.31, 0.12, and 0.17 mSv/yr, while surface measurements at the "burnt stone" had the highest AED (0.41 mSv/yr). ADR and AED were both considerably higher than the world average of 59 nGy/hr and 0.07 mSv/yr. The average effective lifetime cancer risk (ELCR) (0.77×10-3) was higher compared to the world average of (0.25×10-3), with the highest in the granites. The ELCR risk band indicated a concern for increased cancer risk. Educating the public about actions to reduce their exposure to environmental carcinogens is necessary.
Eugene Echeweozo; A.D Asiegbu; E.L. Efurumibe; L.A. Nnanna; H.K. Idu
Abstract
Gamma radiation shielding of baked and unbaked granite bricks produced with 0%, 10%, 20%, 30%, 40%, and 50% of kaolin powder were experimentally and theoretically assessed for possible deployment in liquid radioactive waste storage. A 3×3 ...
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Gamma radiation shielding of baked and unbaked granite bricks produced with 0%, 10%, 20%, 30%, 40%, and 50% of kaolin powder were experimentally and theoretically assessed for possible deployment in liquid radioactive waste storage. A 3×3 inches NaI(Ti) detector and WinXCOM program were used to measure the linear attenuation coefficients at different energies. Elements composition of samples were analyzed using particle induced X-ray emission (PIXE) spectroscopy. Results show that adding kaolin to granite positively reduced the liquid permeability coefficients of the bricks but negatively reduced the shielding properties of the bricks. Optimum results were obtained from unbaked sample of granite brick produced with 50% of micro scale kaolin powder (GK50) with mass attenuation coefficient of 0.0663, 0.0572 and 0.0552 cm2.g-1, radiation protection efficiency (RPE) of 38.36%, 34.11% and 33.13% for radiation energies levels of 661.6, 1173.2, and 1332.5 keV respectively and liquid permeability coefficient of 6.53×10-11 m.s-1. The study concludes that all brick samples were thermally stable, good in gamma radiation shielding and efficient in liquid radioactive waste immobilization.
