Radionuclide contents and radiological risk to the population due to raw minerals and soil samples from the mining sites of quality ceramic and pottery industries in Akwa Ibom, Nigeria

Samples of domestically produced industrial raw minerals and soil samples from three mining sites of quality ceramic/smelting and pottery industries in Akwa Ibom, Nigeria, were collected and analyzed for their 226Ra, 232Th and 40K contents using gamma-ray spectroscopy. The range of activity concentrations of the radionuclides in the industrial raw minerals were 17.55 ± 1.63 to 80.99 ± 2.61 Bq.kg-1 for 226Ra, 7.64 ± 0.77 to 23.94 ± 0.92 Bq.kg-1 for 232Th and 63.22 ± 3.43 to 503.90 ± 5.69 Bq.kg-1 for 40

Assessment of radiation exposure levels at Alaba e-waste dumpsite in comparison with municipal waste dumpsites in southwest Nigeria

Radiation exposures at the e-waste dumpsite around Alaba International Market, Lagos and three municipal waste dumpsites located in Ibadan and Ado Ekiti, southwest Nigeria were assessed by gamma ray spectroscopy using a highly shielded Canberra NaI (Tl) detector. Soil samples were collected for analysis at the municipal waste dumpsites for comparison with e-waste dumpsite. Samples were also collected at a location free from waste dumps to serve as control. The mean concentrations of 40K, 226Ra, and 232Th obtained at the e-waste dumpsite were lower than those obtained at the municipal waste dumpsites and the controls site. The values obtained at the e-waste dumpsite were also lower than the world average values of 412 Bq/kg, 35 Bq/kg and 30 Bq/kg for 40K, 226Ra, and 232Th, respectively as reported by UNSCEAR. The mean annual effective dose rate obtained for the soil samples from e-waste dumpsite, Oritaperin, Ring-road and Ilokun dumpsites were respectively 0.026 mSv, 0.074 mSv, 0.080 mSv and 0.093 mSv/yr. The mean absorbed dose rate at the e-waste dumpsite was 21.12nGy/h which is lower than the world average of 60nGy/h. Values for other hazard indices were below the world average and lower than their respective minimum permissible limits. Hence, e-waste and municipal waste does not pose any immediate radiological risk to the people working/living in the vicinity of the dumpsites. Keywords: Dose assessment, E-waste, Dumpsites, NaI(Tl) detector, Southwest Nigeri

Comparison on in situ and laboratory gamma-ray spectroscopy of terrestrial gamma radiation in Ibadan, Southwestern Nigeria

In situ - ray spectroscopic method of measeruments, using the calibration factor by Zombori et al, and laboratory method for soil samples were carried out in Ibadan, SW Nigeria. The average specific activities of 40K, 238U and 232Th in the soil were 299.0 16.5 Bqkg-1, 40.0 5.8 Bqkg-1 and 95.0 7.8 Bqkg-1, respectively, by in situ measurements, while for the laboratory measurements, the specific activities were found to be 355.0 19.7 Bqkg-1 for 40K, 31.0 5.9 Bqkg-1 for 238U and 63.0 7.5 Bqkg-1 for 232Th. Statistical analysis using F- hypothesis test of microsoft excel 5.0 analysis toolpak gave F-values to be 0.32, 0.52 and 0.00, respectively, which indicated that the radionuclides were not site dependent. The comparison shows a correlation of 0.65, 0.59 and 0.63 respectively, for 40K, 238U and 232Th. Key words : gamma - ray; calibration; soil; activity; radionuclide (Global Journal of Pure and Applied Sciences: 2002 8(4): 507-512

Patient size-specific models for tube load selection during diagnostic examination of patient trunk

Each time a radiograph is to be produced a set of exposure parameters such as tube load (mAs-product of tube current and exposure time), tube potential (kV), focus to skin distance (FSD) are selected such that it produces optimal image required for diagnosis. The choice of exposure parameters depend on the nature and part of the body to be examined- its thickness, density and pathology. Therefore, optimal exposure is required to obtain adequate diagnostic information at the same time conforming to the principle of optimisation. Exposure parameter selection during conventional radiography is largely donebased on the discretion of the Radiographers, except where digital technology (facility equipped with automatic exposure control-AEC) is available. This practice has resulted in the production of low quality image and error in diagnosis. However, in order to select appropriate technical parameters, it is essential to understand the anatomical composition of a patient during diagnostic examination. This study demonstrates models for determining patient thicknesses (trunk area) using patient weight. And it also describes the application of the model obtained in the selection of tube load during diagnostic examination. Software based on National Radiological Protection Board (NRPB) optimal tube loads was developed to execute the simple model for adult patient trunk. Results obtained were compared with the tube load values used during the real time examinations