Department of Nuclear Safety and Security
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Item Natural radioactivity level and evaluation of radiological hazard in the soil around a gold mining area in the North Region of Burkina Faso(International Journal of Global Environmental Issues, 2022) Kabore, K.; Darko, E.O.; Bambara, L.T.; et al.The activity concentrations of natural radionuclides 226Ra, 232Th and 40K in soil samples from the North Region of Burkina Faso around the mining site of Kalsaka were measured by gamma spectrometry using high purity germanium detector. Radiological hazard assessment due to such natural radioactivity was also investigated. The average activity concentration of 226Ra, 232Th and 40K were found to be 26.06 ± 1.50 Bq.kg-1, 33.27 ± 1.97 Bq.kg-1, and 133.11 ± 13.69 Bq.kg-1, respectively. The average absorbed dose was 0.038 µGy/h, whereas the annual committed effective dose was 0.050 ± 0.003 mSv.y-1. The average radium equivalent activity concentration was 83.89 Bq.kg–1. The external and internal hazard indices were 0.23 and 0.30, respectively, which are three times less than one. The activity utilisation index was 0.6 bq/kg, with maximum of 0.79 bq/kg. The mean effective dose rate of 0.05 ± 0.003 mSv.y-1 and the mean values of Raeq, Hex and Hin for the studied area are below their respective permissible limits, thus indicating that radiation hazard is not significant in this area.Item Stable Isotopes and Water Level Monitoring Integrated to Characterize Groundwater Recharge in the Pra Basin, Ghana(Water, 2023) Manu, E.; De Lucia, M.; Akiti, T.T.; Kühn, M.In the Pra Basin of Ghana, groundwater is increasingly becoming the alternative water supply due to the continual pollution of surface water resources through illegal mining and in discriminate waste discharges into rivers. However, our understanding of hydrogeology and the dynamics of groundwater quality remains inadequate, posing challenges for sustainable water re source management. This study aims to characterize groundwater recharge by determining its origin and mechanism of recharge prior to entering the saturated zone and to provide spatial estimates of groundwater recharge using stable isotopes and water level measurements relevant to groundwater management in the basin. Ninety (90) water samples (surface water and groundwater) were collected to determine stable isotope ratios of oxygen (δ 18O) and hydrogen (δ 2H) and chloride concentra tion. In addition, ten boreholes were installed with automatic divers to collect time series data on groundwater levels for the 2022 water year. The Chloride Mass Balance (CMB) and the Water Table Fluctuation (WTF) methods were employed to estimate the total amount and spatial distribution of groundwater recharge for the basin. Analysis of the stable isotope data shows that the surface water samples in the Pra Basin have oxygen (δ 18O) and hydrogen (δ 2H) isotope ratios ranging from −2.8 to 2.2h vrs V-SMOW for δ 18O and from −9.4 to 12.8h vrs V-SMOW for δ 2H, with a mean of −0.9h vrs V-SMOW and 0.5h vrs V-SMOW, respectively. Measures in groundwater ranges from −3.0 to −1.5h vrs V-SMOW for δ 18O and from −10.4 to −2.4h vrs V-SMOW for δ 2H, with a mean of −2.3 and −7.0h vrs V-SMOW, respectively. The water in the Pra Basin originates from meteoric source. Groundwater has a relatively depleted isotopic signature compared to surface water due to the short residence time of infiltration within the extinction depth of evaporation in the vadose zone. Estimated evaporative losses in the catchment range from 51 to 77%, with a mean of 62% for surface water and from 55 to 61% with a mean of 57% for groundwater, respectively. Analysis of the stable isotope data and water level measurements suggests a potential hydraulic connection between surface water and groundwater. This hypothesis is supported by the fact that the isotopes of groundwater have comparatively lower values than surface water. Furthermore, the observation that the groundwater level remains constant in months with lower rainfall further supports this conclusion. The estimated annual groundwater recharge in the catchment ranges from 9 to 667 mm (average 165 mm) and accounts for 0.6% to 33.5% (average 10.7%) of mean annual precipitation. The total estimated mean recharge for the study catchment is 228 M m3 , higher than the estimated total surface water use for the entire Pra Basin of 144 M m3 for 2010, indicating vast groundwater potential. Overall, our study provides a novel insight into the recharge mechanism and spatial quantification of groundwater recharge, which can be used to constrain groundwater flow and hydrogeochemical evolution models, which are crucial for effective groundwater management within the framework of the Pra Basin’s Integrated Water Resources Management PlanItem Baseline Assessment of Naturally Occurring Radionuclides in Borehole Water of Asikam-Gold Mining Community in Ghana(Elsevier B.V., 2023) Aberikae, E.A.; Kpeglo, D.O.; Nyantakyi, E.K.; et al.The main source of drinking water and domestic usage for the population of Asikam in the Fanteakwa South Municipality is from hand-dug wells and mechanized boreholes. This study assessed naturally occurring radionuclides Radium-226(Ra-226), Thorium-232(Th- 232) and Patassium-40(K-40) in the water from these sources. A random sample of 20 sampling points made up of 7 manually dug wells and 13 mechanically drilled boreholes were taken from Asikam Communities. The radioactive contents of the selected water sources were characterized and analysed using gamma spectrometry system with High Pure Germanium Detector. This assessment was carried out to determine the level of natural radioactivity that the processing of gold ore at the Asikam illegal mining site in Ghana exposes the public to. The mean activity concentrations of Ra-226, Th-232, and K-40 were obtained as 0.30 Bq/L, 0.49 Bq/L, and 2.44 Bq/L in the water samples respectively. The results from this study were found to be lower than the Guidance levels recommended by the World Health Organization (WHO, 2011; IAEA,2014) of 1 Bq/l for Ra-226 and Th- 232. The estimated average committed annual effective dose for water samples was 0.17 mSv/yr which is lower than the 1 mSv/yr recommended limits for public exposure by the WHO. The cancer fatality risk and hereditary consequences from exposure to naturally occurring radionuclides which may result from the Asikam community’s mining and mineral processing operations were evaluated and found to be insignificant. The findings of this study demonstrate radioactivity levels are within the range of natural background radiation levels as reported in the literature, and they compare favorably with findings from comparable studies conducted nationally and internationally. This study provides important baseline information for future research in the study area.Item National inventory of authorized diagnostic imaging equipment in Ghana: data as of September 2020(PAMJ, 2022) Bour, B.K.; Sosu, E.K.; Hasford, F.; Gyekye, P.K.; Achel, D.G.; Faanu, A.; Amoako, J.K.; Pitcher, R.D.Introduction: to address the challenge of inadequate and non-equitable distribution of diagnostic imaging equipment, countries are encouraged to evaluate the distribution of installed systems and undertake adequate monitoring to ensure equitability. Ghana´s medical imaging resources have been analyzed in this study and evaluated against the status in other countries. Methods: data on registered medical imaging equipment were retrieved from the database of the Nuclear Regulatory Authority and analyzed. The equipment/population ratio was mapped out graphically for the 16 regions of Ghana. Comparison of the equipment/population ratio was made with the situation in other countries. Results: six hundred and seventy four diagnostic imaging equipment units from 266 medical imaging facilities (2.5 units/facility), comprising computed tomography (CT), general X-ray, dental X-ray, single-photon emission computed tomography (SPECT) gamma camera, fluoroscopy, mammography and magnetic resonance imaging (MRI) were surveyed nationally. None of the imaging systems measured above the Organization for Economic Co-operation and Development (OECD) average imaging units per million population (u/mp). The overall equipment/population ratio estimated nationally was 21.4 u/mp. Majority of the imaging systems were general X-ray, installed in the Greater Accra and Ashanti regions. The regional estimates of equipment/population ratios were Greater Accra (49.6 u/mp), Ashanti (22.4 u/mp), Western (21.4 u/mp), Eastern (20.6 u/mp), Bono East (20.0 u/mp), Bono (19.2 u/mp), Volta (17.9 u/mp), Upper West (16.7 u/mp), Oti (12.5 u/mp), Central (11.9 u/mp), Northern (8.9 u/mp), Ahafo (8.9 u/mp), Upper East (6.9 u/mp), Western North (6.7 u/mp), Savannah (5.5 u/mp) and North-East (1.7 u/mp). Conclusion: medical imaging equipment shortfall exist across all imaging modalities in Ghana. A wide inter-regional disparity in the distribution of medical imaging equipment exists contrary to WHO´s recommendation for equitable distribution. A concerted national plan will be needed to address the disparity.Item Trace Metals Migration and Contamination Assessment of Groundwater in the Lower Volta River Basin, Ghana(Exposure and Health, 2021) Egbi, C.D.; . Anornu, G.K.; Appiah‑Adjei, E.K.; Ganyaglo, S.Y.; Dampare, S.B.This study was conducted to assess the migration of trace metals (TMs), their sources and potential human health risks in the Lower Volta River Basin (LVRB) of Ghana using preference technique, geometrical analysis, hydrochemistry, TMs evaluation index, correlation matrix and USEPA risk assessment model. Results of enrichment evaluation and geometrical analysis revealed that Fe, Mn, Pb and Ni are the dominant TMs within the unsaturated zone. Moderate vertical migration trends of Pb and Ni in agreement with hydraulic conductivity and Cl− were also displayed. The distribution of the TMs on Ficklin diagram suggests that their dissolution is less depended on the groundwater acidic environments. The mean dominance of the TMs in the groundwater follows the order of Fe > Mn > Ni > Cu > Pb > Zn. Results of TM evaluation index showed that 37%, 57% and 6% of the groundwater are of low, medium and high pollution categories. The hydrochemistry, correlation, biplots and three-dimensional plot jointly revealed that Pb, Ni and Mn occurred in the groundwater as migrating constituents of effluents and agricultural inflows. Also, hydrogeochemical conditions favour vertical migration of Fe. Results of non-carcinogenic risk quotients showed that 6%, 9%, 43% and 100 of the groundwater were above unity for Fe, Mn, Ni and Pb. Hazard index values were > 1 for all human categories. Pb and Ni showed high potential non-carcinogenic risk. Also, Ni showed greater cancer risk for all age groups. The study is key to preventing groundwater quality depletion in the basin.Item Synthesis and characterization of single phase ZnO nanostructures via solvothermal method: influence of alkaline source(Biointerface Research in Applied Chemistry, 2019) Droepenu, E.K.; Wee, B.S.; Chin, S.F.; Kok, K.Y.; Asare, E.A.Single phase ZnO nanostructures were synthesized by simple and low temperature solvothermal process from two different alkaline sources; Potassium hydroxide (KOH) and Sodium hydroxide (NaOH) with zinc acetate dihydrate (Zn(CH3COO)2∙2H2O) as precursor. This facile and rapid synthesis technique achieve high purity of Zinc oxide (ZnO) nanostructures on large scale negating the use of complex and high temperature routes. The synthesized particles were characterized by X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), Transmission Electron Microscopy (TEM), Energy-dispersive X-ray spectroscopy (EDX), Fourier Transform Infrared (FT-IR) Spectroscopy, Ultraviolet Visible (UV-Vis) spectroscopy and Brunauer-Emmett-Teller (BET) analysis. ZnO synthesized using KOH and NaOH exhibit wurtzite hexagonal and flake-like nanostructures with average crystallite size of 11.0 nm and 14.9 nm respectively. Surface area of 59.50 m2/g and 31.43 m2/g were determined for KOH and NaOH sources respectively. The optical absorption spectra of the two samples showed absorption bands of 367.70 and 365.30 nm. The results showed the effect of alkaline sources on the surface morphology, structural and optical properties of ZnO.Item Estimation of Absorbed and Effective Doses in Organs through Computed Tomography Examinations Using Automatic Exposure Control and Fixed Tube Current Techniques: A Phantom Case Study(Iranian Journal of Medical Physics, 2020-01) Sulemana, H.; Inkoom, S.; Sosu, E.K.; Schandorf, C.Introduction: The study aimed to assess absorbed and effective doses in organs through computed tomography (CT) examinations using automatic exposure control (AEC) and fixed tube current (FTC) techniques. Material and Methods: Scanning parameters were obtained for routine adult CT examinations and used to estimate the organ absorbed and effective doses using CT-Expo software. The estimated effective doses were based on International Commission on Radiological Protection publication 103 recommendations. Results: Regarding the scans performed with AEC, doses to head, chest, abdomen and pelvic organs were within the range of 19.7-41.8, 6.4-17.4, 19.2-20.9, and 10.5-24.9 mGy respectively. Moreover, the effective doses for the mentioned organs were 1.6, 6.1, 6.4 and 5.4 mSv respectively. Considering FTC technique, doses to organs ranged 16.7-75.5, 4.1-52.2, 10.6-33.2 and 5.2-38.7 mGy respectively. Moreover, the mean effective doses of FTC were 2.1, 6.9, 9.4 and 6.1 mSv, respectively. Examinations performed with AEC technique induced a dose reduction of 9% and 34% for head organs, 52, 62 and 25% for chest organs, 16% and 14% for abdomen organs, and 11% and 10% for pelvic organs, compared to the FTC. A dose increase of 3% was observed for testes. The mean effective doses for scans with AEC were 13-46% lower than those obtained by FTC. Conclusion: According to the obtained results of the current study, the estimated doses for scans with AEC technique were in a lower level compared to FTC technique. Accordingly, it is recommended to utilize this technique for CT examinations to ensure optimal dose reduction to radiosensitive organsItem Assessment of Nuclear Moisture Density Gauges at a Secondary Standard Dosimetry Laboratory in Ghana during December 2015–December 2017(Iranian Journal of Medical Physics, 2020-01) Owusu-Banahene, J.; Appiah, P.; Adjei, D.N.; Gbekor, B.D.; Amoah, P.A.; Owusu-Manteaw, P.; Amoako, J.K.; Darko, E.O.; Asiedu, G.O.Introduction: Nuclear moisture density gauges are widely used in construction industry in different countries across the world, including Ghana, on a large scale. Like all irradiating devices, the nuclear gauges should be subjected to radiation safety assessment based on radiation protection and safety principles. Regarding this, the objective of this research was to investigate the radiation safety of the nuclear moisture density gauges to ensure the absence of any leakages from the radioactive source. Material and Methods: For the purpose of the study, a survey meter (RADOS-120) was used to measure and record the radiation dose once at a distance of 1 m from the surfaces of all sides of the nuclear moisture density gauge and very close distance from the surfaces of the device. Moreover, the device was examined using radiation contamination test and counts on a standard block. Results: A total of nine nuclear moisture density gauges manufactured by Troxler Electronics Inc. in the USA were evaluated within a period of 3 years. The minimum and maximum average dose rates were 0.49 and 66.67 μSv/h, respectively. The highest and lowest average dose rates were recorded in 2017 and 2016 on the devices with serial numbers of 38260 and 32839, respectively. Conclusion: The assessment of the nuclear moisture density gauges under study revealed no radiation contamination leakage. Furthermore, all the evaluated gauges were shown to function properly and were safe for the intended purposesItem An Investigation into the Infrastructure and Management of Computerized Tomography Units in Ghana(Journal of Medical Imaging and Radiation Sciences, 2020-02-11) Botwe, B.; Schandorf, C.; Inkoom, S.; Faanu, A.INTRODUCTION: In Ghana, there is a need to document computed tomography (CT) infrastructure and management systems for the development of interventions to promote CT practices while ensuring patient protection through the establishment of diagnostic reference levels and improved dose management systems. METHODS: A quantitative inquiry using a descriptive, cross-sectional approach was used to collect data, using a semistructured questionnaire related to CT infrastructure and management from the technical heads responsible for CT scanners. Data collected included the scanner characteristics, basic management system and organizational arrangements, number of attending practitioners, clinical indications for CT examinations, and the operation of CT facilities in Ghana. RESULTS: Of the 35 CT scanners installed across the country, 31 were involved in the study. The majority (29%) were Toshiba models. Equipment slices ranged from 1 to 640, of which 45.2% were 16-slice scanners. Many (n = 28, 90.3%) were functioning, and most were installed in the capital city, Accra. The equipment mean age was 7.3 ± 4.4 years, and 25.6% were 10 or more years old. There were 107 operating radiographers, 60 reporting radiologists, and 10 medical physicists employed across the facilities. A total of 204,760 CT examinations were performed yearly (6.8 CT procedures per 1000 people in Ghana). Head CT procedures were the most common, and suspicion of cerebrovascular accident or stroke (32.8%) was the most common indication. Some basic quality management system and policy driving CT infrastructure in Ghana were lacking. CONCLUSION: The results have provided essential information on the status of CT infrastructure and management systems for policy development and planning in CT facilities in Ghana. This study provides those interested in CT services, jobs, or medical equipment investment in Ghana the information needed to make appropriate decisions.Item Nitrate contamination of groundwater in the Lower Volta River Basin of Ghana: Sources and related human health risks(Ecotoxicology and Environmental Safety, 2020-01-22) Ganyaglo, S.Y.; Egbi, C.D.; Anornu, G.K.; Appiah-Adjei, E.K.; Li, S-L.; Dampare, S.B.A significant population within the Lower Volta River Basin of Ghana relies solely on untreated groundwater (GW) and surface water (SW) for various purposes. However, negative practices associated with increasing human activities pose threats to particularly GW quality in the basin. Using NO3 − as a proxy, this study mainly focused on the status of GW contamination, origins of NO3 − and potential human health risks through integrated hydrochemistry, correlation analysis, isotopes (15N, δ18O), Bayesian and USEPA human health risk models. Slightly acidic to alkaline GW and SW environments were observed. Electrical conductivity (EC) values above 1000 μS/cm were recorded in 45% of the GW with a maximum of 19370 μS/cm. NO3 − in GW ranged from 0.12 to 733 mg/L with average 59.6 mg/L and positively correlated with K+, Ca2+, Mg2+, Cl−, Na+ and EC. In SW, a maximum of 5.3 mg/L of NO3 − was observed. Largely, 75% of the GW exceeded local background NO3 − value of 2.1 mg/L, while 35% were above the WHO recommended value of 50 mg/L. Bivariate and correlation relationships elucidated human contributions to sources of NO3 −, Cl−, SO4 2− and K+ to GW in the basin. From NO3 −/Cl− ratio, 43% of the GW and 21% of SW were affected by effluents and agrochemicals. Values for δ15N–NO3 - and δ18O–NO3 - ranged from +4.2‰to +27.5‰and +4.5‰to +19.9‰for GW, and from +3.8‰ to +14.0‰and +10.7‰to +25.2‰for SW. Manure, septic effluents and mineralized fertilizers are sources of NO3 − contamination of water in the basin. The Bayesian model apportioned 80% of GW NO3 − contamination to sewage/manure. Hazard index indicated 70%, 50% and 48% medium to high-risk levels for infants, children and adults respectively, with 79% high-risk of SW NO2 − contamination to infants. Immediate measures for GW and SW quality protection are recommended.