Search

Measurement of background gamma radiation was carried out in two active municipal dumpsites (Olusosun and Soluos III) in Lagos metropolis, Nigeria. This study aimed to measure absorbed dose rates (ADRs) in the air in relation to distances from the dumpsites and to evaluate the annual effective dose (AED). The measurements of background gamma radiation were carried out at two active municipal dumpsites (Olusosun and Soluos III) for 3 months during the dry season in Lagos, Nigeria, with lithium fluoride thermoluminescent dosimeters (TLDs) which were arranged in a three-dimensional setup to eliminate the angular dependency of TLD dosimeter chips for environmental measurement. The dosimeters were retrieved, analyzed, and replaced at each location every month for the mentioned period. The mean ADR at Olusosun and Soluos III was 24.53-71.88 nGyh-1 with an average value of 52.91 ± 14.41 nGyh-1 and 53.67-100.67 nGyh-1 with an average value of 74.67 ± 11.28 nGyh-1, respectively. The computed mean AED was 0.065 ± 0.018 mSv/year at Soluos III, whereas at Olusosun, it was 0.092 ± 0.014 mSv/year. It was found that the mean values of ADR and AED values at Olusosun were slightly higher than the world's average values but decreased with varying distances away from the respective dumpsites. The people living close to these dumpsites are exposed daily to low-dose gamma radiation emanating from the dumpsites and lie within global background variations. [ABSTRACT FROM AUTHOR]

Elevated radon concentrations in drinking water pose an increased risk of cancer among nonsmokers. A Monte-Carlo Simulation was employed to assess the effective dose and cancer risk associated with radon exposure in humans, utilizing a systematic review and meta-analysis of related studies. These studies were sourced from databases including PubMed, Web of Science, Scopus, Science Direct, and Google Scholar, focusing on drinking water from Nigeria's six geopolitical zones. The random effects models revealed a 222Rn concentration in drinking water of Nigeria at 25.01, with 95% confidence intervals (CI) of 7.62 and 82.09, indicating significant heterogeneity of (I² = 100%; p < 0.001). The probabilistic risk of effective dose revealed a best-scenario (P 5%) at Kundiga and Magiro that exceeded the World Health Organization's (WHO) recommended effective dose limit of 200 µSv/y. Conversely, the worst-case scenario (P 95%) indicated concentrations surpassing the recommended limit at Kundiga, Edbe, Magiro, Ekiti, and Abeokuta. Excess Life Cancer Risk for infants, children, and adults attributed to the ingestion and inhalation of radon from various drinking water sources exceeded the recommended values of 0.2 x 10-3 established by the International Commission on Radiological Protection (ICRP) and the United Nations Scientific Committee on the Effect of Atomic Radiation (UNSCEAR). It underscores the necessity for treating radon-polluted water, employing methos such as aeration and granular activated carbon (GAC) processes. [ABSTRACT FROM AUTHOR]

The radiological risks associated with exposure from radioactivity in soil from oil and gas producing coastal areas of Nigeria have been assayed after sixty years of exploration activities in the area. This is to ascertain the radiological impact on the oil field workers and residents of host communities. Gamma spectrometric technique was used to determine the radiometric in the soil samples collected using a highly efficient a Canberra High Purity Germanium Dedector (HPGe) detector. The obtained mean activity concentrations of the three natural radionuclides of 40 K, 238U, and 232Th are 1586.82 ± 17.97, 27.26 ± 8.38, and 37.67 ± 9.55 Bqkg−1 respectively. The estimated mean radium equivalent for the host communities and the control sample values are 203.31 ± 23.56 Bqkg−1 and 20.17 ± 2.54 Bqkg−1 respectively. The radiation risk estimates from three exposure routes, external, inhalation, and ingestion, were calculated using the activities of the radionuclides detected in the soil samples. The measured concentrations are higher than the corresponding global average values. The estimated total effective dose received by the residents and oil field workers through the three exposure routes ranged from 0.21 to 14.8 mSvy−1 with a mean value of 4.77 mSvy−1. The values of each of the total effective dose estimated in the different communities exceeded the 1.0 mSvy−1 permissible limit for the general public. The estimate dose equivalent obtained for external exposure is 4.27 μSvy−1 which represents 89.0% of the permissible limit for the general public. These results obtained show that both residents and oil field workers are significantly exposed to radiation from the soil which may be of radiological health concern. [ABSTRACT FROM AUTHOR]

Mined Trona is a naturally occurring inorganic salt that is consumed by humans for diverse purposes in Nigeria. Due to the increase in consumption rates of these salts following a renewed government interest in solid minerals exploration and exploitation, it is imperative to assay its radiological content. Reconnaissance survey revealed that the most commonly used Trona varieties were: Farar Kanwa, Jan Kanwa, Dan Libya, Ngurnu, Manda, Farar Balma, Jar Balma and Yar Agadez. Samples of the identified Trona varieties were purchased from markets within Zaria, Nigeria. The samples were analysed using NaI (Tl) gamma ray spectrometry system. Radium equivalent activity (Raeq), annual effective dose (AED), Internal and Alpha hazard Indices (Hin and Iα) and total cancer risks (TCR) were used to assess the radiological safety of its consumption. The activity concentration of 238U (226Ra); 232Th and 40K varied widely and had an average ± error values of 42.904 ± 4.54 Bq/kg, 11.96 ± 1.41 Bq/kg and 455.28 ± 10.56 Bq/kg respectively. Raeq, AED, Iα, Hin and TCR were estimated at 95.07 ± 63.10 Bq/kg, 68.52 ± 52.53µSv/y, 0.21 ± 0.23, 0.37 ± 0.27 and (390.57 ± 299.44) × 10 − 06 respectively; which were by far less than the US EPA and UN SCEAR acceptable thresholds. It was established that the threshold consumption rate is 40 Kg/year and any value slightly higher than the threshold values will be associated with a significant radiological health risk. Therefore, at the present consumption rate of Trona in Nigeria, there is no cause for radiological concern. [ABSTRACT FROM AUTHOR]

This research explores the measurement of background nuclear radiation, rate of exposure and the radiological risk for the inhabitants of South-western Nigeria. The measurement was carried out using Rad*Scanner model 500VBR, which measures radiation dose in count per minute. The mean absorbed dose rate ranges between 147.26 ± 8.13 nGy h−1 and 228.20 ± 20 nGy h−1, the annual and collective annual outdoor effective dose equivalent, with collective health detriment were estimated using the obtained data. The mean annual outdoor effective dose equivalent was estimated at 268.37 ± 38.25 µSv y−1. This value is below 1 mSv y−1 limit recommended by ICRP but greater than 0.1 mSv y−1 recommended by WHO. Using a population of 3,441,024, the mean collective effective dose equivalent was estimated at 923.46 ± 131.619 Man-Sv y−1. The collective health detriment was estimated to be approximately 15 men which could vary depending on hours of exposure. [ABSTRACT FROM AUTHOR]

Background: Hysterosalpingography (HSG) is an indispensable tool for diagnosing infertility in females. The procedure exposes female reproductive organs to ionizing radiation as the genitals are irradiated during the process. Investigating patient absorbed dose during the procedures is essential for effective radiological protection of the patient. Objective: This study aims to investigate the radiation dose received by patient during HSG examination in the study environment in order to enhance optimization of procedures and the associated dose, thereby minimizing radiation risks. Material and Methods: The prospective pilot study, was conducted in four tertiary healthcare institutions in Southwest Nigeria. Thermoluminescence dosimeter (TLD 100) was used to determine the Entrance Surface Dose (ESD) of 80 patients presented for HSG investigation. The corresponding effective dose, ovary, uterus and urinary bladder doses were evaluated using PCXMC software. Results: The mean entrance surface doses (ESD) obtained from the four centers were 18.58±6.31 mGy, 15.18±2.27 mGy, 17.44±3.43 mGy and 34.24±11.98 mGy for SW1, SW2, SW3 and SW4 centers, respectively. The corresponding mean of effective doses were 1.54±0.63 mSv, 1.24±0.28 mSv, 1.41±0.30 mSv and 2.53±0.94 mSv for SW1, SW2, SW3 and SW4 centers, respectively. The resulting mean doses to the ovary, urinary bladder and uterus were also presented. Conclusion: The results obtained in general are comparable with international standards. It was, however, recommended that study centers with high doses should conduct dose audit in order to enhance patient safety. [ABSTRACT FROM AUTHOR]

Background: Computed tomography urography (CTU) is an efficient radiological examination for the evaluation of urinary system disorders. However, the procedure exposes patients to a substantial amount of radiation dose associated with increased cancer risks. Objectives: To determine computed tomography (CT) dose index following CTU and to evaluate organs equivalent doses and cancer-induced risks. Materials and Method: A prospective cohort study was carried out at a tertiary health facility in Kano, Northwestern Nigeria. Ethical approval was sought and obtained. Patients Demographics scan parameters and CT radiation dose data were obtained from patients that had CTU procedure. Effective dose (ED), organ equivalent doses, and cancer risks were estimated using SPSS statistical software version 16 and CT dose calculator software. Results: A total of 56 consented patients were included in the study, consisting of 29 males and 27 females. Radiation dose data for CTU was estimated as follows: dose length product (2,320 mGy*cm), computed tomography dose index (9.67 mGy), and ED (34.5 mSv). The probability of cancer risks was also estimated to be 600 per a million CTU examinations. Conclusion: The study revealed that the radiation dose for CTU is considerably high with increase in cancer risks probability. Variations in ED between studies suggest that optimization is not fulfilled. Patient radiation dose estimate should be taken into consideration when imaging protocols are planned for CTU. [ABSTRACT FROM AUTHOR]

The demand for abdominal Computed Tomography (CT) scans has dramatically increased over the years due to its higher sensitivity in ruling out a wide range medical conditions as compared to other imaging modalities. However, this patronage is associated with high effective dose and hence attributable to the risk of radiation-induced injuries. Establishing an acceptable radiation dose level and designing a protocol of maintaining dose level within that range is a sure optimization practice that is recommended by most national and international radiation monitoring bodies. The study aims to assess the average radiation dose received by patients undergoing abdominal CT examinations in Radiology unit of AKTH Kano, Nigeria. Dose survey of 100 adult abdominal CT scans in Radiology department of AKTH from June-October 2018. CTDIvol and DLP were simply obtained from the CT machine as displayed on the console and recorded into an adapted IAEA survey form. Effective dose was estimated by multiplying DLP by the conversion factor, k-value for abdomen (0.015mSv/mGy.cm). A total of 100 patient's radiation dose summary comprising 57 (57%) of females and 43 (43%) males with a mean age of 46 years. Determined 75th percentile CTDIvol, DLP and effective doses for abdominal CT were found to be 12 mGy, 2225.25 mGy.cm and 33.38 mSv respectively. The CTDIvol value was lower than most local and international established studies. The DLP and effective doses of the present study were significantly higher than other studies and calls for review of existing protocol to optimize practice. [ABSTRACT FROM AUTHOR]

Introduction Exposure to chronic levels of ionizing radiation could be detrimental to health even at very low doses. Calabar free trade zone (CFTZ) was established to promote export business in Nigeria and it is yet to produce exposure data of the Zone. Materials and Methods The Zone was divided into three categories depending on the type of business. Category A had facilities with manufacturing businesses, Category B was service providers while Category C was oil and gas businesses. Exposure levels within the CFTZ were measured with exposure meter and results obtained were converted to annual effective dose in mSv/yr. The evaluated doses were used to estimate health risks to workers in the Zone in terms of lifetime cancer incidence and mortality for persons aged between 18 - 65 years using the conversion factors in BEIR VII. Results Category B facilities had dose values between 0.21 - 0.31 mSv/yr followed by Category A with dose values between 0.23 - 0.35 mSv/yr. Category C facilities had the highest dose values between 0.33 - 0.40 mSv/yr. The evaluated cancer incidence and mortality rates were generally less than 2 persons in 1,000 persons for both male and female workers. Conclusion The study shows that the exposure levels in business facilities within the CFTZ were higher than the background radiation level. The effective doses were not uniform for the different categories. The estimated cancer incidence and mortality were low, and simple linear equations were generated to relate cancer incidence to mortality. [ABSTRACT FROM AUTHOR]

The radon level of some selected dwellings of southwestern Nigeria was investigated using CR-39 detectors. Seventy 6.25 cm2size detectors were distributed to 70 homes randomly within two states of southwestern Nigeria for between three and four months, after which chemical etching and counting were carried out. Concentration values ranged from 5 to 255 Bq/m3, and the average radon concentration measured in the dwellings under study was 39 ± 7 Bq/m3. A mean annual effective dose rate of 1 mSv/y was determined for the selected dwellings. It was concluded that the radiological health implications resulting from these values are very low or almost insignificant. [ABSTRACT FROM PUBLISHER]

Despite the fact that disruption of the environment through mining of minerals poses severe radiological hazards, there is a dearth of radiological information from gold mining sites in Nigeria. In this study, state-of- the-art computational tools - RESRAD ONSITE, RESRAD OFFSITE and ERICA were applied to a typical representative artisanal goldmining area for a more comprehensive evaluation of radiological risks associated with artisanal gold mining in Nigeria. The estimated doses received by an offsite receptor is within the radiation basic safety limit, while for onsite receptor it is greater than the basic radiation safety limit. It was observed that onsite dwellers of the artisanal goldmining areas may suffer high cancer burden when compared with the US EPA acceptable levels. For non-human biota, the hazard quotient was greater than unity and the total dose rate per organism was greater than the screening dose rate of 10μGy h−1. It was observed that 232Th and 226Ra were the main contributors to the total dose and the pathways that contributed most to the dose were; external exposure (via direct and airborne radiation from soil and Radon) as well as water independent plant, meat and milk consumption. Therefore, monitoring food production will lead to an informed decision making and risk communication towards sustainable mining will contribute in minimizing the level of the anticipated risks as low as reasonably achievable. • There is a dearth of radiological information from artisanal gold mining sites in Nigeria. • The estimated doses received by offsite receptors is within the radiation basic safety limit. • The estimated doses received by onsite receptors is greater than the basic radiation safety limit. • Non-human biota are subjected to radiation hazards in the artisanal goldmining areas in Nigeria. [ABSTRACT FROM AUTHOR]

Gamma ray spectrometric technique has been used to determine activity concentrations of some primordial radionuclides in the naturally occurring uranium, actinium and thorium series and of non-series40K in soil samples collected from five major towns in Oyo State, Southwestern Nigeria. Activity concentration determination was done using a high purity germanium (HPGe) detector. It ranged from 85.83 ± 4.04 Bq kg−1to 1,850.60 ± 36.83 Bq kg−1for40K; 5.23 ± 0.34 Bq kg−1to 198.31 ± 4.10 Bq kg−1for208Tl (indicator for232Th) and 7.82 ± 0.42 Bq kg−1to 64.65 ± 2.00 Bq kg−1for214Bi (indicator for238U). The outdoor absorbed dose rate in air due to each of the primordial radionuclides was calculated from the mean values of the activity concentration in each sample. Values ranged from 3.60 ± 0.17 nGy h−1to 77.73 ± 1.55 nGy h−1for40K, 3.48 ± 0.23 nGy h−1to 132.07 ± 2.73 nGy h−1for208Tl and 3.35 ± 0.21 nGy h−1to 27.73 ± 0.86 nGy h−1for214Bi. The absorbed dose rate in air was the highest for rocky areas, while the lowest value came from non-rocky, non-industrialized areas. The estimated annual outdoor effective dose equivalents for the two rocky areas were 385.76 μSv y−1and 221.28 μSv y−1. The estimated annual outdoor effective dose equivalents for the two industrialized areas were 64.05 μSv y−1and 47.65 μSv y−1. The value for non-rocky, non-industrialized areas was 19.19 μSv y−1. The average value for the study area was 147.59 μSv y−1. The estimated collective effective dose equivalent for the area was 9.77 × 102man-Sv y−1. The expected number of people in the study area at risk of incurring cancer per year as a result of radioactivity in the soil was estimated to be 11; this value represents approximately 7% of the estimated 160 people for 18 Nigerian cities, approximately 69% of 16 people estimated for oil producing areas of Nigeria and less than the United States Environmental Protection Agency regulatory limit of 1 cancer case to 10,000 people. Also, this result shows that local variability of natural radionuclides in soil depends on local geology of the area. The incidence number was 2.4 people per million. [ABSTRACT FROM AUTHOR]

The radioactivity concentrations of 226Ra, 232Th and 40K were measured using gamma-ray spectroscopy with NaI (Tl) detectors in four tantalite mining sites in the Oke-Ogun area, South-Western Nigeria. The measured values of the activities of 40K, 226Ra and 232Th in the soil samples were found to lie in the ranges 123.7 ± 3.8 - 1372.3 ± 8.6, 16.8 ± 1.6 - 71.1 ± 2.53 and 3.0 ± 0.7 - 31.9 ± 1.0 Bq kg-1, respectively. These samples were also found to have radium equivalent activity in the range 74.2-121.0 Bq kg-1. Values of 0.2-0.3 for the external and 0.3-0.4 for the internal hazard indices were estimated for the samples and the annual effective dose varied from 70.3 ± 13.5 to 100.8 ± 42.8 μSv with a mean of 87.5 ± 18.6 μSv y-1. The annual effective dose is higher than the world average. [ABSTRACT FROM AUTHOR]

• 222Rn, gross α and β radioactivity levels are higher than USEPA limits. • The annual effective dose for the ingestion of 222Rn, gross α and β radioactivity is too high. • Drinking water from the artisanal goldmines are radiologically unsafe for drinking. Artisanal gold mining activities in Shanono and Bagwai local governments of Kano state Nigeria is a serious threat to the quality of drinking water in the area. This work was carried out to assess the radon, gross alpha and gross beta radioactivity in drinking water sources from artisanal gold mining villages in Shanono and Bagwai local government areas of Kano state, Nigeria. Water samples were collected and analysed for gross α and β radioactivity using a non-gas proportional counter with model protean instrument corporation MPC 2000DP single channel and for 222Rn using liquid scintillation counter (Tri-Carb-LSA1000). 222Rn, gross α and β radioactivity had average concentrations of 36.101, 0.142 and 0.285 Bq/L respectively. The annual effective dose for the ingestion of 222Rn, gross α and β radioactivity were 0.264, 0.228, 0.457mSv/year for adults; 0.395, 0.114, 0.229mSv/year for children and 0.461, 0.057 and 0.114mSv/year for infants respectively. These values were higher than the ICRP, WHO, UNSCEAR and USEPA recommended safety limits, indicating that the water is not safe for drinking and domestic purposes in terms of radiological consequences. [ABSTRACT FROM AUTHOR]