Annual Effective Dose Research Articles

Direct measurement of indoor thoron and radon progeny and estimation of inhalation dose in three cities in Gabon: Comparison of the use of thoron typical and measured equilibrium factor values

This study focuses on public exposure to natural radioactivity caused by the inhalation of radon and thoron progeny in homes in Franceville, Moanda and Mounana in Gabon. The equilibrium factor (FTn) between thoron and its progeny was determined experimentally for a proper estimate of the effective dose. In order to assess internal exposure due to radon and thoron progeny, 150 passive radon-thoron discriminative detectors (RADUET) and thoron progeny monitors were deployed for about 3 months in the above-mentioned towns. The results of the measurements obtained showed that the average concentrations of thoron progeny (EETC) were 1.54 ± 0.08 Bq m−3, 3.05 ± 0.09 Bq m−3 and 1.84 ± 0.11 Bq m−3 in Franceville, Moanda and Mounana, respectively. The ranges of the measured thoron equilibrium factors were 0.004–0.710, 0.005–0.750, and 0.006–0.794 in Franceville, Moanda and Mounana, respectively. The arithmetic and geometric mean values were, respectively, 0.183 and 0.117 in Franceville, 0.184 and 0.122 in Moanda, and 0.221 and 0.140 in Mounana. The experimentally determined equilibrium factor (FTnexp) allowed us to compare the value of the experimentally determined effective dose with the theoretically determined one calculated using the equilibrium factor proposed by United Nation Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) 2000 report. FTnexp values were around 6–11 times greater than the UNSCEAR typical value. The ranges, arithmetic and geometric mean EERC values determined were 30.40–55.60 Bq m−3, 24.00 ± 0.90 Bq m−3 and 41.68 (1.00) in Franceville, 36.40–62.50 Bq m−3, 45.30 ± 0.70 Bq m−3 and 44.72 (1.00) in Moanda, and 35.00–90.00 Bq m−3, 50.00 ± 2.00 Bq m−3 and 48.50 (1.00) in Mounana. The mean values of the annual effective inhalation dose due to thoron progeny determined using FTnexp were 0.32 mSv (compared to 0.049 mSv), 0.63 mSv (compared to 0.103 mSv), and 0.39 mSv (compared to 0.055 mSv) in Franceville, Moanda and Mounana, respectively. The main conclusion of this study is that indirect estimations of thoron progeny concentrations considerably underestimate the estimation of the annual effective inhalation dose.

Evaluation of radioactivity levels and hazard indices of Th-232, Ra-226 and K-40 in sediment and water samples of Lake Victoria, Jinja, Uganda

This study evaluates the levels of natural radioactivity in sediment and water samples from Lake Victoria in Jinja, Uganda, with a focus on the radionuclides potassium-40 (40 K), radium-226 (226Ra), and thorium-232 (232Th). We investigated four distinct zones around the lake: fishing (Zone A), farming (Zone B), domestic/livestock (Zone C), and a control zone (Zone D). A total of 15 sediment samples and 15 water samples were collected and analyzed. Sediment samples were obtained using a gravity corer, with a maximum penetration depth of 50 cm. 40 K ranged from 170.479 to 524.883 Bqkg−1 across all zones, 226Ra ranges from 1.51 to 56.78 Bqkg−1 across all zones, and 232Th ranges from 18.18 to 73.10 Bqkg−1 across all zones. 40 K concentrations were highest in the farming zone, likely due to the use of nitrogen, phosphorus, and potassium (NPK) fertilizers. 226Ra and 232Th levels were also elevated in the farming zone, suggesting potential contributions from phosphate fertilizers. Absorbed dose rates varied across the zones, ranging from 28.33 to 58.17 nGyh-1. The measured absorbed dose rates across all zones were within the global average of 59 nGyh−1. The effective annual dose rate ranged from 0.35 to 0.91 mSvy−1 across all zones. Effective annual dose rates did not exceed the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) recommended limit of 1 mSv y−1, indicating low risks to public health from sediment radioactivity. The external index was below the safety threshold, suggesting minimal health risks. In water samples, gross alpha and beta activity concentrations were analyzed. Zone B had the highest average alpha activity concentration (0.64 BqL−1) and beta activity concentration (0.72 BqL−1), while Zone A had the lowest for both alpha (0.16 BqL−1) and beta (0.25 BqL−1) activity concentrations. Gross beta activity was generally higher than gross alpha activity, reflecting potential anthropogenic influences. Most water samples were within the UNSCEAR recommended limits for drinking water quality, except in areas affected by agricultural runoff. This study demonstrates that while the sediments of Lake Victoria in Jinja, Uganda, exhibit varying levels of naturally occurring radionuclides influenced by farming practices, the overall radiation exposure remains within safe limits. Continuous monitoring and regulatory measures are essential to maintain these safety levels and mitigate potential risks from increasing agricultural activities.

Assessment of radiological risk to workers and members of the public from the operation of a groundwater treatment plant in Jordan

ABSTRACT The study aimed to evaluate the radiation doses received by workers at a pilot water treatment plant (WTP) in Jordan. It also examined the concentrations of gross alpha, gross beta, and radium activities in both groundwater and treated water, along with a radiological risk assessment for the waste generated by the treatment process. The radioactivity levels of gross alpha and gross beta in the groundwater were found to exceed the established drinking water limits. In the pilot WTP, two methods were applied for water treatment, namely, ceramic ultra-filtration (CUF) and reverse osmosis (RO), both of which produced treated water that met drinking water quality standards. The annual effective dose from external radiation exposure to the WTP workers was found to be less than 0.007 mSv y−1 (during the filters backwash operation). However, the average annual dose from internal radiation due to inhalation of radon released from groundwater reached 3.2 mSv y−1, exceeding the 1 mSv y−1 limit. Therefore, monitoring radon levels in workplaces is recommended. Radioisotope concentrations in the waste (sludge) stockpiles exceeded clearance levels, requiring them to be treated as radioactive waste. Overall, the WTP successfully produced drinking water that met quality standards, and the methods used could be replicated in other locations.

Features, reasons, and significance of radon and thoron attributable radiological dose in the indoor environment

Humans receive around 50% of natural radiation dose due to 222Rn (radon), 220Rn (thoron) and their decay products. Several field campaigns measuring these gases and the decay products in different regions of India have been conducted in the recent past. Some of these studies measured indoor activity concentration and/or dose due to these gases and the associated decay products. This work compares the fraction of 222Rn and decay products and 220Rn and decay products in inhalation dose for 10 studies conducted in Uttarakhand state. It is seen that AEDT (annual effective dose due to 220Rn and decay products) for these regions varies between 21 and 48% and it is significantly higher than the averaged worldwide reference value of 6%. Based on elaborative measurements performed in the Bageshwar district (present work), Almora and Nainital districts (our previous campaigns); the reasons for this high value have been explored. It was observed that a higher source term for mud houses could be the main reason for the high AEDT range. Interestingly, preliminary analysis revealed that the fraction is higher for the dwellings situated at higher altitudes thus indicating the role of the unavailability of modern building construction materials at remote locations. The study highlights the significant contribution of thoron in the Indian Himalayas.

ASSESSMENT OF THE LEVELS OF NATURAL RADIOACTIVITY AND THE POSSIBILITY OF RADIATION RISKS IN SOIL SAMPLES TAKEN FROM DIFFERENT LOCATIONS IN SOUTHERN ALMAZAR-ALKARAK, JORDAN

A wide study of environmental radioactivity levels in soil samples from Southern Almazar-Alkarak in Jordan was performed to develop a radiological map of the area. 15 soil samples were collected from different locations across the region and subjected to analysis using a high-purity germanium detector (HPGe). The study showed that the average levels of natural radionuclides 226Ra, 232Th, 238U and 40K were 34.5±0.98, 25.6±1.3, 32.2±3.7 and 278.5±15.7 Bq.kg−1, respectively. Also, to evaluate the radiological danger, the radium equivalent activity (Raeq) is calculated, absorbed gamma dose rate (D), annual effective dose equivalent (AEDE) and external hazard index (Hex), internal hazard index (Hin). The average values for these parameters were determined to be 92.5 Bq.kg−1, 43.0 nGy h−1, 52.7 µSv y−1 and 0.25Bq.kg−1, 0.34Bq.kg−1 respectively. The values of the gathered samples stay below the allowable limits. Consequently, the examined region does not present any radiation risk to the general population. Moreover, it has been discovered that there is no concentration of 137Cs radionuclide activity in the studied area.

Continuous monitoring of outdoor natural gamma absorbed dose rate in air: a long-term study in Kolkata, West Bengal, India

AbstractThis study contributes to the overarching Indian Environmental Radiation Monitoring Network initiative, concentrating on the continual assessment of the gamma absorbed dose rate in outdoor air attributable to natural gamma radiation in Kolkata, West Bengal, India. Over a span of fourteen years (2011–2024), data were gathered from 32 monitoring sites within the city utilizing permanently installed Geiger-Mueller detector-based environmental radiation monitors. This paper offers an analysis of extensive findings from long-term monitoring efforts. The absorbed gamma dose rate in outdoor air varied among the monitoring sites, ranging from 78 ± 5 to 137 ± 4 nGy h− 1, with a mean value of 107 ± 12 nGy h− 1. The estimated mean annual effective dose due to outdoor natural gamma radiation ranged from 0.10 ± 0.01 to 0.17 ± 0.01 mSv y− 1, with an overall mean of 0.13 ± 0.01 mSv y−1.

Activity Concentration of Natural Radionuclides in Surface Sediments of Major River Watersheds in Korea and Assessment of Radiological Hazards

The assessment of potential radiation hazards in accumulated sediments in aquatic ecosystems is vital for the management and disposal of sediments. Furthermore, preemptive management of radionuclides in terrestrial ecosystems is critical for marine ecosystem conservation. We analyzed the activity concentrations of natural radionuclides (226Ra,232Th, 238U, and 40K) in the surface sediments of major river watersheds in Korea and evaluated the radiation hazards stemming from these activity concentrations. The mean activity concentrations of 226Ra and 238U were lower than the global average, whereas those of 232Th and 40K were higher. The mean values of radium equivalent activity, external hazard index, and internal hazard index calculated from these activity concentrations did not exceed the recommended maximum values. The mean values of absorbed gamma dose rate in air and annual outdoor effective dose rate (AEDRout) were higher than the global average by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) but remarkably lower than the recommended and background values by the International Commission on Radiological Protection (ICRP) and the Korea Institute of Nuclear Safety (KINS). The contribution of 40K and 232Th to the AEDRout mean value was predominant. In conclusion, the surface sediments of major river watersheds in Korea are associated with negligible radiation hazards. These findings provide fundamental data for the management and treatment of sediments in terrestrial and marine ecosystems.

Assessment of radiological contamination due to gold mining in soil and food crops of Babban Tsauni, Gwagwalada, Nigeria.

This work assessed the activity concentrations of 238U(226Ra), 232Th, and 40K and their associated radiological risks due to exposure to soil and consumption of food crops in Babban Tsauni artisanal gold mine, Gwagwalada, Nigeria, using the gamma spectrometry technique. The mean activity concentrations of 226Ra, 232Th, and 40K in the mine soil were 60.2±9.9, 161.4±16.2, and 664.6±138.2, while they were 46.4±4.9, 79.9±39.3, 266.4±185.4 for tubers and 46.9±15.7, 100.5±35.8, 311.4±132.7 (Bq/kg) for grains, respectively. The results reveal that the activity concentrations of radionuclides in all samples exceeded the recommended values set by United Nations Scientific Committee on the Effects of Atomic Radiation (33, 45, and 420 Bq/kg) except 40K, which fell within the acceptable limit in all food crop sample types. Estimated results for radiological hazard parameters, radium equivalent, annual effective dose due to ingestion, and excess life cancer risk were within safe limits, while the annual effective dose due to external gamma radiation in soil and annual gonadal equivalent dose were significantly high in all investigated samples; these call for constant radiological monitoring.

Determination of natural radioactivity levels in soil samples from irrigated vegetable farming land in and around Addis Ababa, Ethiopia.

Soil samples were collected from vegetable agricultural areas in and around Addis Ababa, and their levels of radioactivity were measured. Gamma spectrometry with high-purity germanium detector was used to quantify radioactivity level. The average concentration of 226Ra, 232Th, and 40K were 32.8±2.1, 62.4±4.4, and 544.3±23.3Bqkg-1 respectively. The mean values of 232Th and 40K are higher, whereas the value of 226Ra is comparable with world average values. Radiological hazard indices, including radium equivalent activity (Raeq), absorbed dose rate (Dr), outdoor annual effective dose equivalent (Deff), external hazard index (Hex), internal hazard index (Hin), and gamma radiation representative level index (Iγ), were calculated based on the activity concentration of 226Ra, 232Th and 40K. The mean values were 163.9Bqkg-1, 78.7 nGy h-1, 0.10mSv y-1, 0.44, 0.53, and 0.60 respectively. All indices are lower than global recommended limit values. These results revealed that radiation hazard due to radionuclides in the soil of the study area is insignificant.

Assessment of Soil Radioactivity Associated with Risk and Correlation with Soil Properties near Maanshan Nuclear Power Plant, Taiwan

This study analyzes the concentration of radioactive material in the soil near the Maanshan nuclear power plant (NPP). Out of the thirty samples, only one sample was found to have 137Cs radioactivity measuring 2.58 Bq/kg. The activity concentrations were 77.2–517.7 Bq/kg, 3.9–31.6 Bq/Kg, and 5.3–39.1 Bq/kg, respectively, with mean values of 344.4 Bq/kg, 18.6 Bq/kg, and 26.5 Bq/kg for 40K, 226Ra, and 232Th, respectively. These levels are lower than the global average of soil activity concentrations. The activity concentrations varied, with the highest levels being 7–8 times greater than the lowest levels. Clay content had a positive correlation and sand content had a negative correlation with 40K, 226Ra, and 232Th activity concentrations. The activity concentrations followed a normal distribution for 40K, 226Ra, and 232Th. The activity ratios for 232Th/226Ra, 40K/232Th, and 40K/226Ra were 1.43 ± 0.22, 13.1 ± 1.9, and 18.8 ± 4.1, respectively, and ratios show light minerals in the soils. The average values for external hazard indices (Hex) and radium equivalent activity (Raeq) were 0.22 Bq/kg and 83.0 Bq/kg, respectively, both of which are below the recommended limit values of 1.0 Bq/kg and 370 Bq/kg, respectively. The outdoor absorbed dose rate (DRex) and annual effective dose equivalent (AEDex) were 39.0 nGy/h and 47.8 μSv/y, respectively, both of which are lower than the global soil average of 59 nGy/h and 70 μSv/y, respectively. These results indicate that local residents and tourists are not at significant risk of radiological hazards from the soil. The soil activity concentrations can serve as a baseline for continuous monitoring, even after the Maanshan NPP is decommissioned in 2025.

Assessment of the activity concentration of radon and its health hazard in surface water around the Rooppur Nuclear Power Plant (RNPP) site, Bangladesh

ABSTRACT Radon is a colourless, unscented, radioactive inert gas. As a gaseous element, Rn-222 can be effectively breathed in, leading to a health hazard. The main objective of this study is to measure the amount of Rn-222 concentration in surface water and its associated health hazards around the Rooppur Nuclear Power Plant (RNPP) construction site area in Bangladesh. Twenty water samples were collected each year (2022 and 2023) from different specific locations of the Padma River and investigated for radon concentration through a Durridge RAD7 detector with RAD H2O accessories. The range of radon activity in surface water measured from 0.070 ± 0.035 to 0.385 ± 0.211 BqL−1 with a mean activity of 0.194 ± 0.114 BqL−1 in the year 2022 and in the year 2023, the range of radon activity in surface water measured from 0.035 ± 0.070 to 0.455 ± 0.239 BqL−1 with an average activity of 0.228 ± 0.140 BqL−1. All the radon concentration results were below the recommended limits of WHO (100 BqL−1) and USEPA (11.1 BqL−1). The ranges of annual effective dose (AED) were from 0.1911 to 1.051 µSvy−1 and from 0.095 to 1.242 µSvy−1 in the years 2022 and 2023, respectively, which were lower than the AED recommended by WHO (0.1 mSvy−1). The mean values of excess lifetime cancer risk are 0.0021 × 10−3 and 0.0025 × 10−3 in the years 2022 and 2023, respectively, which were lower than the average standard value recommended by UNSCEAR (0.29 × 10−3). The result of this investigation can be applied as baseline data for radon concentration measurement in the under-construction nuclear power plant site area vicinity of Bangladesh.

Evaluation of Radioactivity Concentration and Hazard Indices in ash Some Hospitals Incinerators in Baghdad / Al Resafa

Due to their harmful effects on human health and their tendency to cause cancer, radionuclide concentrations and risk indicators have been measured in hospital incinerator ash. This was done by collecting samples ash of Hospitals Incinerators, examining them, and identifying the risks that emerged from the examination. Three samples Only taken for the study from certain hospitals affiliated with the Baghdad Al-Rusafa Health Department. High purity germanium gamma spectrometer (HPGe) were used to analyze the samples. The concentrations of potassium isotopes (K-40) range from (147.1±16.5 to 214.4±21.1 Bq/kg), While the range of concentrations for Ra-226 isotopes is (7.52±1 to 19±1.8 Bq/kg), and lead (Pb-212) isotope concentrations ranged from (10.1±1.1 to 11.1±1.5 Bq/kg). In addition, the isotope concentration of actinium (Ac-228) is 8.05±1. Radium equivalent (), risk index , annual effective dose equivalent radioactivity level index ), absorbed dose rate D, and lifetime cancer risk were calculated. The results showed that no radiation risk Only indicated by any of the risk indicators. This indicates that the ash from the hospital incinerator does not pose any radioactive danger.

Patients’ effective doses assessment during low-dose computed tomography

Computed tomography has become increasingly common for diagnosing socially significant diseases in recent years. In foreign practice, screening schemes for lung cancer in people belonging to risk categories have been developed and implemented. These schemes have been successfully used over the past 10 years. In this case, “low-dose” scanning protocols are used, which make it possible to perform examination with patient effective dose several times lower compared to standard protocols. Lung cancer screening methods using low-dose computed tomography are beginning to be introduced in the Russian Federation. To ensure the radiation safety of those individuals eligible for inclusion in screening programs or participating in biomedical research testing lung cancer screening, it is necessary to evaluate effective doses from low-dose computed tomography and compare these doses to established radiation dose limits. This study assessed the patients’ effective doses who underwent different types of low-dose computed tomography of chest at two medical organizations. The results of the study show that it is possible to achieve non-exceedance of the current annual effective dose limit of 1 mSv only for patients weighing less than 90 kg. For patients with higher body weight, the minimum effective dose will be in the range of 1.2 – 1.4 mSv. The results of the study indicate the need to make changes to the current regulatory and methodological documents of Rospotrebnadzor to ensure the possibility of using low-dose computed tomography as part of screening for all categories of people.

Radionuclides determination by alpha (210Po, 228,230,232Th) and gamma (226,228Ra, 137Cs, 40K) spectrometry in children's food in Croatia with assessment of cumulative ingestion dose for infants

This work presents comprehensive results of alpha (210Po, 228,230,232Th) and gamma (40K, 226,228Ra, 137Cs) radioactivity measurements in selected food typically consumed by infants (< 1 year) in Croatia. The samples of readily available infant’s food on Croatian market were categorized according to the growth of an infant, from their first nourishment: adapted powdered milk, to their first solid food. The aim was to estimate ingestion doses and the potential radiological risks for infants. In addition to anthropogenic radionuclides, the study focused on naturally occurring radionuclides often underrepresented in similar researches. 40K prevails in activity concentrations in all types of samples. 210Po was determined in all sample types reaching up to 502 mBq/kg. Maximum values of activity concentrations for 228Ra, 226Ra and Th isotopes were 230 mBq/kg, 1.29 Bq/kg and 52 mBq/kg, respectively. The most important contributors to the annual effective dose were 40K, 226Ra, 210Po and 228Ra contributing with 29 % 28 %, 24 % and 17 %, respectively. Th isotopes contributed with less than 2 %, while the contribution of anthropogenic radionuclides 137Cs and 90Sr were negligible (less than 1 %). Cumulative effective ingestion dose for infants was calculated to be 0.69 mSv/y, which is below the recommended limiting dose of 1 mSv/y. Largest proportion comes from the intake of fruit (33 %), followed by the intake of vegetables 19 %) and cereals 19 %). Although national radioactivity monitoring programs usually focus on anthropogenic radionuclides, this study highlights that naturally occurring radionuclides are dominant contributors to the cumulative effective ingestion dose in infants. Overall, the estimated cumulative effective ingestion dose for infants from consuming food available in Croatia is below recommended dose limits and therefore does not present a radiological concern.

Estimation of radon annual effective dose and excess lung cancer risk for the residents of KufrKhal, Jordan

This study aims to measure radon gas concentration, calculate the annual effective dose, and calculate excess lung cancer risk in KufrKhal-Jerash north of Jordan. Radon is a radioactive gas located everywhere and contributes more than 40% of people’s total dose from natural radiation. The Risk concerns have resulted from the increase in mortality due to lung cancer in KufrKhal. About 117 well-calibrated dosimeters were among the study area’s districts (Hill 1, Hill 2, Hill 3, and village center). Each dosimeter consists of a plastic cup with known dimensions and a piece of solid state nuclear track detector (SSNTD) type CR-39 fixed in the inner bottom of the cup. After 90 days, the retrieved detectors were chemically etched, and the track density (tracks.cm−2) was determined. The results showed that the average radon concentrations drastically varied between the districts of KufrKhal (17.1–128.8 Bqm−3). However, the mean radon values in different districts are closely related (64.4–75.5 Bq.m−3). The lowest concentration (17.1 Bqm−3) was found in the Hill 1 district, and the highest value (128.8 Bqm−3) was found in the village center. However, the overall radon concentration in KufrKhal was approximately 69.2 Bqm−3. This value is within the range of the national average level (43.2 – 77.4 Bq.m−3) and way below the national action level (200 Bq.m−3). Furthermore, the corresponding values of the annual effective dose (AED) and the excess lung cancer risk (ELCR) for dwellers in this village were calculated to be 1.8 mSv.y−1 and 0.2%, respectively. These values, according to Jordan’s national regulations are acceptable.

Radiation dose to health care workers measured by thermoluminescent dosimetry

To evaluate radiation dose among physicians, nurses, nuclear medicine (NM) technicians, and radiographers at a single institution and to compare the difference in the measured dose during COVID-19 with other periods. A retrospective analysis of the occupational radiation doses received by all workers in diagnostic radiography and NM departments at a single institution during a 5-year period (2018-2022) was performed. Dose measurements were recorded for 94 radiology personnel: radiographers, NM technicians, physicians, and nurses. In addition to descriptive statistics, the Mann-Whitney U-test was used to compare the average annual effective dose between male and female workers and between the periods before and during COVID-19. Kruskal-Wallis test was used to compare effective radiation doses from different quadrants. The annual average effective doses were found to be between 0.58 and 0.72 mSv for males and 0.68 and 0.85 mSv for females. All radiographers, 86% of nurses, and 69% of physicians have received annual average effective doses below 0.99 mSv. The average annual effective doses for all radiation workers were similar in the period before COVID-19 when compared to the period during COVID-19 except for nurses who had significantly lower (P<0.05) doses before COVID-19. The average annual effective doses of radiation workers during 2018-2022 were well below the annual dose limit. A relatively higher average effective dose was received among NM technicians compared with other radiation occupational workers. While the caseload during the COVID-19 pandemic was lower due to government policies, the radiation dose to healthcare workers during the pandemic was similar to that before the pandemic.

Radiometric hazard assessment of soil and water samples adjacent to Bangladesh's first nuclear power plant before commissioning: Insights into human health and environmental radiological dynamics

The current study provides a comprehensive examination of both natural and anthropogenic activity concentrations found in soil and surface water samples near the Rooppur nuclear power plant (RNPP), the first of its kind under construction in Bangladesh. The investigation covers a range of activity concentrations including 226Ra, 232Th, and 40K in fifty soil and fifty water samples, revealing values ranging from 18 to 38, 18–51, and 310–560 Bqkg−1 for soil, and 2.1–6.1, 2.1–5.5, and 67–115 Bqkg−1 for water, respectively. Although outdoor absorbed dose rate, outdoor effective dose, and gamma representative level index values in some soil samples exceed global averages, other radiological hazard parameters such as radium equivalent activity, annual effective dose, external and internal hazard indices, and lifetime carcinogenic risk for both soil and water samples consistently remain below safety thresholds established by international organizations. These findings indicate that the soil and water samples collected from the vicinity of the RNPP do not pose significant radiological hazards to the nearby populations. This study's comprehensive dataset is anticipated to play a crucial role in facilitating the identification and evaluation of any changes in environmental radioactivity, thereby assisting in the effective management and regulation of nuclear power plant activities in the years to come.

Radiological Risk Assessment of Building Materials Used in Federal College of Education (Technical) Akoka, Lagos State, Nigeria

Multiple building constructions necessitating a regular influx of different soils for building purposes within Federal College of Education (Technical) Akoka, in Lagos State, Nigeria spurred a radiological risk assessment of selected soil samples. Five (5) construction points were identified and ten (10) soil samples were collected. A gamma spectrometer was used to evaluate the natural radionuclides (226Ra, 232Th, and 40K) present in the soils. IAEA-certified standard materials of RGU-1, RGTh-1, and RGK-1 were used to determine the full peak efficiencies of gamma energies 609, 1120, and 1764 keV for 238U, 2614 keV for 232Th and 1460 keV for 40K. Activity concentration, absorbed dose, annual effective dose equivalent, hazard indices, and excess lifetime cancer risk (ELCR) were estimated to assess possible radiological risks in the building soil samples. Results from the analysis revealed the highest radioactivity among soil samples was 674.3 Bq/kg from 40K and the lowest was 18.5 Bq/kg from 226Ra. The absorbed dose (D) varies from 65.8 nGy/h to 215.3 nGy/h with an average value of 136.6 nGy/h, and the annual effective dose equivalent ranged from 0.081 mSv/y to 0.264 mSv/y with an average value 0.168 mSv/y. The internal and external hazard index ranged from 0.49 −1.46 and 0.39 − 1.32 respectively which is not completely below the hazard index threshold value ≤ 1 as recommended by UNSCEAR. The ELCR values ranging from 0.222 × 10-3 − 0.726 × 10-3 with an average value of 0.461 × 10-3 predicted an insignificant carcinogenic risk with the probability of four persons in every 10,000 persons.

Use GIS Technical to map Natural Radioactivity in Soil Samples for the University of Kufa, Iraq

GIS "Geographic Information System" technology was used to map the specific activity (S.A.) of primordial radionuclides 238U, 232Th, and 40K in selected soil samples for twelve locations at the University of Kufa, Iraq. S.A. values were determined using gamma spectrometry type NaI(Tl) with volume “3×3”. Also, the values of radiological parameters such as Raeq“radium equivalent”, Hex “external hazard index”, Iγr “representative gamma risk index”, Dr “Absorbed Dose rate, AEDEoutdoor “Annual Effective Dose Equivalent in outdoor”, and ELCR “Excess Lifetime Cancer Risk” were determined. The average value of S.A. for 238U, 232Th, and 40K was 10.35±0.9 Bq/kg, 7.31±1.8 Bq/kg, and 256.19±55.7 Bq/kg, respectively. While, the average values of Raeq (Bq/kg), Hex, Iγr, Dr (nGy/h), AEDEoutdoor (mSv/y), and ELCR were 48.00, 0.130, 0.373, 23.70, 0.029, and 0.102×10-3, respectively. The results of S.A. and each radiological parameter of the study area locations were low according to acceptable level reports by UNSCEAR, ICRP, and OCDE. Therefore, it can be concluded that the soil samples of the University of Kufa were safe.

Modeling of long-term radiological and toxicological impacts of the uranium mill tailings on groundwater and surface water

Modeling predictions are presented of radionuclide transport processes in the zone of influence of the Zahidne uranium mill tailings situated at the Prydniprovsky Chemical Plant (PChP), Kamianske. The groundwater transport model was developed using the NORMALYSA software. Refined estimates of parameters of water exchange in the zone of uranium mill tailing (obtained from field studies and modeling of groundwater flow processes) were used to parameterize the model for radionuclide transport in groundwater. Calibration of the radionuclide transport model using monitoring data on radioactive contamination of groundwater in 2005 - 2021 allowed to estimate the sorption distribution coefficient (Kd) for the most hazardous contaminants 238,234U isotopes (Kd = 8 ± 2 l/kg) and estimate the rate of uranium migration in groundwater. According to modeling, during the next 800 to 1100 years, uranium concentration in wells in the zone of influence of uranium mill tailing (at 500 - 800 m distance) will be determined mainly by the contamination of the alluvial aquifer, which was formed during the operation period of the uranium mill tailing. According to modeling predictions, usage of groundwater (partial drinking water consumption, irrigation) outside the PChP site downstream of the uranium mill tailing will result in doses exceeding the relevant reference level (annual effective dose &gt; 1 mSv/year) in 380 - 440 years, while the toxicological impact will result in the exceeding of the acceptable hazard index for uranium (HI &gt; 1) in 200 - 260 years. Modeling results indicate the importance of restricting the use of groundwater downstream of the uranium mill tailing within the PChP industrial site and, in the longer term, beyond its boundary. At the same time, contamination of the Konoplyanka River due to the migration of radionuclides from the uranium mill tailing does not pose unacceptable radiological and toxicological risks for the considered scenario (irrigation, fish consumption) due to the dilution of contaminants in surface waters.