Radiological Impact Research Articles

Assessment of dose rates to non-human biota from radioactive discharges from Sellafield Ltd. using PC-CREAM

PC-CREAM is a tool for assessing the radiological impact of routine discharges of radionuclides to the environment. It can be used for prospective assessments, to calculate doses to members of the public for authorisation of proposed discharges, or for retrospective assessments of previous discharges where doses are compared with dose limits. These types of assessment are a fundamental requirement of regulations governing the control of radioactive discharges. However, the latest publications of the basic safety standards for radiation protection, EU (Council of the European Union, 2014) and the IAEA (IAEA, 2014), now include the requirement to demonstrate protection of the environment as well as members of the public. To this end, a module has been added to PC-CREAM for calculating dose rates to non-human biota (Anderson et al., 2022). The methodology used for this calculation is based on the recommendations contained in ICRP Publication 108 (ICRP, 2008), which provides a general framework for protection of the environment. The additional module means that PC-CREAM can be used to assess doses to humans and dose rates to biota in an integrated way, for the same set of discharges and using the same dispersion models. This paper describes an assessment of dose rates to biota living in the vicinity of the Sellafield nuclear site, carried out using the new biota module of PC-CREAM. Historical discharges from Sellafield to the sea and atmosphere were considered for the period 1951 to 2017, excluding those from the Windscale fire in 1957. Dose rates calculated for marine biota (flatfish, crabs and brown seaweed) are less than 1 mGy d−1 and are below the lower derived consideration reference level (DCRL) for the ICRP marine reference animals and plants (RAPs). Dose rates for terrestrial biota (bees, deer, earthworms, frogs, wild grass, pine trees and rats) are less than the relevant lower DCRL for terrestrial RAPs, ie 0.1 mGy d−1. Dose rates were also calculated for a user defined organism ‘seabird’ to represent birds which inhabit both marine and terrestrial environments near Sellafield. For seabird, the lower DCRL of 0.1 mGy d−1 is exceeded throughout the 1950s, 1960s and 1970s, when the discharges were at their highest, due to exposures from the marine environment. Since the mid-1980s, no dose rates were calculated that exceeded the lower DCRLs.

Radiological Impact Assessment of Natural Radionuclides and Heavy Metal Contamination in Industrial Tin-Tailing Processing Effluent

This study investigates the radiological hazard and heavy metal contamination of water effluents from Malaysian tin-tailing processing plants. Samples were collected from retention ponds in seven separate tin tailing processing plants scattered throughout the state of Perak, Malaysia. Samples were analysed for radioactivity and heavy metal concentration using Gamma-ray Spectrometry System and Inductively Coupled Plasma-Mass Spectrometry, respectively. The analysis indicates that the concentration of Radium-226 (226Ra), Radium-228 (228Ra), and Potassium-40 (40K) in samples ranged from 2.4 - 34.9 Bq/l, 0.8 - 14.7 Bq/l, and 19.5 - 299.4 Bq/l, respectively. These levels surpassed the control limits (5 Bq/l and 10 Bq/l for 226Ra and 228Ra) set by the regulatory authority. The analysis of the heavy metal contamination showed that the concentration of Arsenic (As) and Lead (Pb) werehigher than the Maximum Concentration Level (MCL) of 0.01 and 0.015 mg/L, respectively. Further evaluation of radiological impact showed that the average Annual Effective Doses (AED) by water ingestion and AED for external exposure are 1.43±0.67 mSv/y and 1.71±0.79 mSv/y, respectively. While for non-carcinogenic and carcinogenic risk assessments, the value of hazard index and lifetime cancer risk is 2.1×10-10 and 1.2×10-7, respectively. These research findings suggest that effective treatment of the effluent should be implemented before discharge into the drainage system to prevent the accumulation of radionuclides and heavy metals in the environment, which may pose a risk to public health.

Radiological environmental monitoring of groundwater around NPP: A proposal for its assessment

Whether a nuclear installation has radiological impact and, in that case, its extension, are the questions behind any environmental analysis of the installation along its operational life. This analysis is based on the detailed establishment of the radiological background of the area.Accordingly, the dismantling and decommissioning process (D&D) of a nuclear power plant starts with a radiological monitoring plan, which includes the radiological characterization of the area and of its surroundings. At the completion of the D&D, unrestricted use for the site will be permitted strictly in accordance with results of the radiological survey within the limits established by the local authorities.Groundwater quality is typically included in any radiological analysis since, among other reasons, a significant part of it is highly likely to end up being extracted for domestic use and hence, human consumption.While there is no regulation containing maximum activity concentration or radionuclide guidance values for water that may be destined for uses other than public consumption, if groundwater is considered a “part” of the land, dose criteria for site release can be applied. Therefore, together with the guidance levels to be established for the different radionuclides expected in the groundwater, the detection limits to be employed when performing routine radio analytical characterization procedures in the laboratory should also be provided.In this paper, we first propose a relation of the potential radionuclides to be analyzed in groundwater, together with their detection limits to be achieved when the determinations are performed in a laboratory, and subsequently, we discuss the most suitable analytical methodologies and resources that would be necessary to undertake radiological characterization plans from a practical point of view.

Environmental Modeling for Radiation Safety

The newly launched IAEA project MEREIA (MEthods for Radiological and Environmental Impact Assessment; 2021- 2025), MEREIA continues some activities of previous IAEA exercises in the field of radioecological modelling and focuses on areas where the probabilistic approach determines the predictive capability of environmental models. The program offered the opportunity to set up well-designed and verified scenarios to collect and compare exposures predicted by particular models based on this scenario and then perform a validation study of contributing models. It consists of the comparison of model prediction with observed data or in the case where there is a lack of measurement data to perform a comparison within model prognoses. The previous international works have brought significant improvement in environmental modeling in terms of better understanding and mathematical description of complex physical and chemical phenomena that occur in various environmental media and also have promoted new areas for experimental investigations. The new experimental results yielded updated handbooks of a large number of environmental parameters for less-known elements. Moreover, the principal objective of the activities in environmental modelling was an integrated risk assessment of the reference group of population and biota associated with radionuclides releases from various kinds of nuclear facilities as from different types and power nuclear reactors, radioactive waste disposal and more complex nuclear research facility. This reflects recent international recommendations to extend protection against radiation hazards of humans to wildlife flora and fauna. However, the statistics supported knowledge on some essential environmental parameters still remain small. Therefore, one could be aware of some limitations of the probabilistic approach that required advanced methods of probabilistic prognosis Monte Carlo.

Assessment of natural radioactivity and associated radiological risks from soils of Hakim Gara quarry sites in Ethiopia

One of the ways of minimizing radiation risks to workers and the public is assessing potential sites that are suspected of producing radiation. Among such locations, quarry sites stand out because areas of granite and other rocks, especially those of uranium family potentially have high concentrations of radiation. This study was aimed to assess one such quarry sites (Hakim Gara site), located near Harar town, Harari region-Ethiopia. To assess the radiological impact of natural radioactivity of quarry activities in the study area, activity concentrations of natural radionuclides 238U, 232Th, 226Ra and 40K in the soil samples were investigated by collecting twenty composite soil samples from different sites of the area. Measurements were carried out using high purity germanium (HPGe) Gamma Spectrometry detecting system for acquisition of data and making analysis using Genie 2000 software. From the result, mean Activity concentration of 238U, 232Th and 40K obtained were 51.9 ± 15 Bq/kg, 68.32 ± 9.75 Bq/kg and 220.0 ± 2.0 Bq/kg, respectively. Average Activity concentration of the 226Ra was 32.71 ± 2.02 Bq/kg. These values were used to calculate and estimate the radiological risks due to environmental radiation exposure contributed from the quarrying activities. The average external and internal hazard indices were 0.45 ± 0.09 mSv/y and 0.49 ± 0.23 mSv/y both of which were below the permissible limit of unity. The results obtained for 238U and 232Th were higher and significant from the world average which need further regulatory monitoring. The level of 40K was below the world average. Hence, this research provided a foundation for future studies on subsequent investigations and to aid realistic regulatory and policy decisions.

Comparison of methods for the radiological impact assessment of aquatic releases to the waters in the low countries

Accurate assessment of the radiological impact of liquid discharges on the marine environment is challenging despite all developments in recent years. The lack of consensus on this type of assessment manifests itself even stronger when transborder issues are expected, such as in the Low Countries. Belgium and the Netherlands operate nuclear power plants with discharges in the shared estuary of the Western Scheldt, therefore if there are safety concerns, information on both sides of the border must be coherent. This work provides a comparison of two computational methods used for assessment of aquatic releases in the Western Scheldt estuary and the adjacent North Sea.The work demonstrates a fair degree of consistency in modelling the uptake and fate of key anthropogenic radionuclides. Nevertheless, there are also considerable differences found in sediment and sea species with concentrations ranging by over two orders of magnitude in some cases. These explainable differences are methodological in nature, occurring in codes that underwent extensive validation during development. Therefore, the outcomes of this work clearly demonstrate the need to produce explicit guidance that is specifically tailored to the (inter)national water system of concern. This should not be limited to releases from nuclear power plants, but also include other nuclear applications. For all these reasons, more intensive collaboration and model harmonisation across borders is essential, signalling the direction for future investigations.

Evaluation of the probability of overflow from the Abadia de Goiás repository by the Fokker-Planck equation using the Trotter’s formula

A model was constructed with the objective of developing the Fokker-Planck equation for the calculation of the reliability attributes required for risk-informed decision-making involved in the analysis of water infiltration inside the repository located in the Abadia de Goiás municipality, in the metropolitan region of the city of Goiânia. The solution of the Fokker-Planck equation was analytically obtained by the Trotter’s method for a near surface repository. This solution provides the probability density and the probability functions for the height of the liquid (water + radionuclides) column, generated by the infiltrated water in the concrete crypt of the repository. The modeling was unidimensional, and the calculations were performed for the geometric center of the repository crypt, which is the place of greater sensitivity of occurrence of accidental scenarios. The concept of the present model can be extended to other places in the crypt without loss of generality. The developed model is appropriate to analyze the repository overflow, a kind of event that occurs when the height of the liquid column inside the repository reaches the value of the inner height of the concrete crypt of the facility. This accident scenario produces the greatest release of radioactive material to the region outside the repository and, consequently, it is responsible for the main radiological impact for both members of the public and the environment. Calculations performed for the Abadia de Goiás repository indicated that the overflow probability for this facility is strongly dependent on the rainfall rate and also on the institutional time period, varying from about 3% with no rainfall penetration up 99% with the maximum rainfall rate for an institutional time period control of 300 yr. Such results can help making decisions on the problem of risk scenarios related to the disposal of radioactive waste.

Daytime, evening, and overnight: the 24-h radiology cycle and impact on interpretative accuracy.

To assess the influence of time of day when a study is interpreted on discrepancy rates for common and advanced studies performed in the acute community setting. This retrospective study used the databank of a U.S. teleradiology company to retrieve studies between 2012 and 2016 with a preliminary report followed by a final report by the on-site client hospital. Neuroradiology, abdominal radiology, and musculoskeletal radiology studies were included. Teleradiologists were fellowship trained in one of these subspecialty areas. Daytime, evening, and overnight times were defined. Associations between major and minor discrepancies, time of day, and whether the study was common or advanced were tested with significance set at p = .05. A total of 5,883,980 studies were analyzed. There were 8444 major discrepancies (0.14%) and 17,208 minor discrepancies (0.29%). For common studies, daytime (0.13%) and evening (0.13%) had lower major discrepancy rates compared to overnight (0.14%) (daytime to overnight, RR = 0.57, 95%CI: 0.45, 0.72, p < 0.01 and evening to overnight, RR = 0.57, 95%CI: 0.49,0.67, p < 0.01). Minor discrepancy rates for common studies were decreased for evening (0.29%) compared to overnight (0.30%) (RR = 0.89, 95%CI: 0.80,0.99, p = 0.029). For advanced studies, daytime (.15%) had lower major discrepancy rates compared to evening (0.20%) and overnight (.23%) (daytime to evening, RR = 0.77, 95%CI: 0.61, 0.97, p = 0.028 and daytime to overnight, RR = 0.66, 95%CI: 0.50, 0.87, p ≤ 0.01). Significantly higher major discrepancy rates for studies interpreted overnight suggest the need for radiologists to exercise greater caution when interpreting studies overnight and may require practice management strategies to help optimize overnight work conditions. The lower major discrepancy rates on advanced studies interpreted during the daytime suggest the need for reserving advanced studies for interpretation during the day when possible.

Formation of authigenic grey monazite: A palaeo-thermal anomaly marker in very-low grade metamorphic rocks?

Reassessment of France’s rare earth element (REE) potential led us to investigate REE behaviour in the black shales of the Middle Ordovician Angers-Traveusot Formation in central Brittany (France). This study focuses on the distribution of nodular grey monazite (up to 200 g/t) within the shales, which formed in response to the diagenetic and low-grade metamorphic evolution of the studied area. Whole rock geochemistry, rock–eval pyrolysis and evolution of clay mineral crystallinity were firstly used to determine temperature and mass transfer conditions in the black shales. Then, monazite texture, composition and U–Pb in-situ dates were determined, and correlated with the diagenetic/anchimetamorphic conditions. Nodular monazite appears in the Ordovician black shales at the transition between high-grade diagenesis and the anchizone metamorphic facies, in response to processes controlled by competing influences such as organic matter maturation, Fe oxide/hydroxide reduction and clay transformation with accompanying fluid release. Monazite occurs mainly as elongated nodules, up to 2 mm in diameter that are characterised by their grey colour caused by an abundance of host-rock mineral inclusions. Monazite nodule compositions are zoned with Nd and middle REE-rich cores surrounded by Ce-rich rims, with no evidence of inherited domains. Ce-monazite also occurs as a replacement of nodular monazite or in late-stage fractures. Zoned nodular grey monazites were dated at ca. 403.6 ± 2.9 Ma, which is proposed to record the high heat flux that led to the anchimetamorphic conditions found at the base of the Angers-Traveusot formation, prior to the Variscan deformation. Crystallisation of the metamorphic Ce-monazite occurred at two periods, dated at 382.6 ± 2.9 Ma and 349.6 ± 6 Ma, which correspond to pre-collisional and collisional tectono-metamorphic stages respectively. Nodular grey monazite constitutes an interesting alternative economic solution because of its very low content in both Th (X¯=2160 ppm) and U (X¯=145 ppm) and negligible radiological impact if mined. However, placers currently display a limited economical interest.

Radiological Impact Assessment of Acute Tritium Releases in Environment—A Soil Dynamic Model

Radiological and environmental impact assessment models are important tools that support nuclear safety. The present study summarizes the upgrades of a research-grade model (CROPTRIT) with an emphasis on a soil submodel and the balance between air-to-plant and soil-to-plant pathways, together with the needs that must be accomplished by an operational model in order to be applied to nuclear facilities involving large tritium loads.

The NERIS roadmap: research challenges in emergency preparedness, response and recovery

NERIS as a European Platform on Preparedness for Nuclear and Radiological Emergency Response and Recovery (EPR&amp;R) has developed a roadmap setting out the key research challenges for radiation emergency preparedness, response and recovery. Research projects in this field have been summarised to demonstrate how important areas of development have been identified and addressed. Radiation EPR&amp;R has a continuous need to evolve to meet societal demands, but also to keep pace with scientific and technological developments and opportunities and so the NERIS research priorities as published in the Strategic Research Agenda (SRA) are kept under review. Three challenge areas have been identified covering the topics of radiological impact assessment, protective action strategies and establishing a transdisciplinary and inclusive framework for emergency preparedness, response and recovery. The importance of these challenge areas and the underlying key topics for NERIS have been mapped across to the Joint Radiation Protection Roadmap developed by the consortium of European radiation research platforms known as MEENAS. The war in Ukraine triggered a new round of revision of the SRA that resulted in the identification of four topics as new or revised challenges for the NERIS community. These updated challenges are: (1) optimisation of management strategies for the transition and recovery phase, (2) uncertainty quantification, data assimilation and monitoring strategies, (3) inverse modelling, and (4) lessons identified from Ukraine and implications for emergency preparedness. These four areas will form the priority research areas for the NERIS community to help advance radiation emergency preparedness to meet current challenges and needs that have been identified.

Assessment of Radiological Hazards in Some Foods Products Consumed by the Malian Population Using Gamma Spectrometry

Background: Food consumption is one of the most important routes for radionuclide intake for the public; therefore, there is the need to have a comprehensive understanding of the amount of radioactivity in food products. Consumption of radionuclide-contaminated food could increase potential health risks associated with exposure to radiation such as cancers. The present study aims to determine radioactivity levels in some food products (milk, rice, sugar, and wheat flour) consumed in Mali and to evaluate the radiological effect on the public health from these radionuclides.Materials and Methods: The health impact due to ingestion of radionuclides from these foods was evaluated by the determination of activity concentration of radionuclides &lt;sup&gt;238&lt;/sup&gt;U, &lt;sup&gt;232&lt;/sup&gt;Th, &lt;sup&gt;40&lt;/sup&gt;K, and &lt;sup&gt;137&lt;/sup&gt;Cs using gamma spectrometry system with high-purity germanium detector and radiological hazards index in 16 samples collected in some markets, mall, and shops of Bamako-Mali.Results and Discussion: The average activity concentrations were 9.8±0.6 Bq/kg for &lt;sup&gt;238&lt;/sup&gt;U, 8.7± 0.5 Bq/kg for &lt;sup&gt;232&lt;/sup&gt;Th, 162.9±7.9 Bq/kg for &lt;sup&gt;40&lt;/sup&gt;K, and 0.0035±0.0005 Bq/kg for &lt;sup&gt;137&lt;/sup&gt;Cs. The mean values of radiological hazard parameters such as annual committed effective dose, internal hazard index, and risk assessment from this work were within the dose criteria limits given by international organizations (International Commission on Radiological Protection and United Nations Scientific Committee on the Effects of Atomic Radiation) and national standards.Conclusion: The results show low public exposure to radioactivity and associated radiological impact on public health. Nevertheless, this study stipulates vital data for future research and regulatory authorities in Mali

Irish general practitioner (GP) perspectives on impact of direct access radiology on patient care in the community: results from a mixed-methods study

BackgroundSince winter 2020/21, general practitioners (GPs) in the Republic of Ireland (RoI) have been granted access to diagnostic imaging studies on a new publicly funded pathway, expediting access to services previously obtained via hospital-based doctors.AimsOutline GP perspectives on imaging studies obtained via the new “GP Access to Community Diagnostics” initiative.MethodsA mixed-methods design was employed. Referrals over the first six months of 2019 and 2021 were collated by a private imaging provider, and a randomly selected subset of 2021 studies (maximum 30 referrals per GP) was returned to participating GPs to provide detail on the impact on each patient’s care. In-depth qualitative interviews were also conducted with participating GPs.ResultsEleven GPs supplied detailed information on 81 studies organized through the new initiative. GPs reported that the initiative had led to a large proportion of cases being managed solely in general practice, with an 81% reduction in referrals to acute hospital settings and a 58% reduction in referrals to secondary care clinics. GPs felt imaging studies improved patient care in 86% of cases and increased GP workload in 58% of cases. GP qualitative interviews revealed four key themes: improved patient care, increased GP workload, reduction in hospital referrals, and opinions on ongoing management of such initiatives, including guidelines.ConclusionsGPs felt enhancing access to diagnostics improved patient care by expediting diagnosis, decision-making, and treatment and by reducing hospital referrals. GPs were generally positive about the initiative and made some suggestions on future management of the initiative.

Sustainability and Climate Protection in Radiology - An Overview.

Sustainability is becoming increasingly important in radiology. Besides climate protection - economic, ecological, and social aspects are integral elements of sustainability. An overview of the scientific background of the sustainability and environmental impact of radiology as well as possibilities for future concepts for more sustainable diagnostic and interventional radiology are presented below.The three elements of sustainability:1. EcologyWith an annually increasing number of tomographic images, Germany is in one of the leading positions worldwide in a per capita comparison. The energy consumption of an MRI system is comparable to 26 four-person households annually. CT and MRI together make a significant contribution to the overall energy consumption of a hospital. In particular, the energy consumption in the idle or inactive state is responsible for a relevant proportion.2. EconomyA critical assessment of the indications for radiological imaging is important not only because of radiation protection, but also in terms of sustainability and "value-based radiology". As part of the "Choosing Wisely" initiative, a total of 600 recommendations for avoiding unnecessary examinations were compiled from various medical societies, including specific indications in radiological diagnostics.3. Social SustainabilityThe alignment of radiology to the needs of patients and referring physicians is a core aspect of the social component of sustainability. Likewise, ensuring employee loyalty by supporting and maintaining motivation, well-being, and job satisfaction is an essential aspect of social sustainability. In addition, sustainable concepts are of relevance in teaching and research, such as the educational curriculum for residents in radiology, RADUCATION or the recommendations of the International Committee of Medical Journal Editors. · Sustainability comprises three pillars: economy, ecology and the social component.. · Radiologies have a high optimization potential due to a significant demand of these resources.. · A dialogue between medicine, politics and industry is necessary for a sustainable radiology.. · The discourse, knowledge transfer and public communication of recommendations are part of the sustainability network of the German Roentgen Society (DRG).. · Palm V, Heye T, Molwitz I et al. Sustainability and Climate Protection in Radiology - An Overview. Fortschr Röntgenstr 2023; 195: 981 - 988.

Biodistribution of naturally occurring radionuclides and radiocesium in wild European perch (Perca fluviatilis)

Wild European perch (Perca fluviatilis) is one of the most important freshwater fish species, in Sweden, due to its widespread and his value for recreational fishing. Little it is known regarding the biodistribution of naturally occurring radionuclides such as 238U, 234U, 226Ra, 210Po in perch. Therefore, in this study, perches from five lakes located in different counties in Sweden were collected to investigate the biodistribution of 238U, 234U, 226Ra, 210Po and 137Cs in organs and tissues of perch as well as their radiological impact. The results showed that uranium radionuclides ranged between 0.1 and 6 Bq/kg with an average value of 1.1 ± 1.5 Bq/kg. 226Ra varied from 0.4 to 8 Bq/kg with a mean concentration of 1.7 ± 1.9 Bq/kg. The ranged of 210Po was 0.5 – 250 Bq/kg, with an average value of 24 ± 52 Bq/kg. On the other hand, the highest activity concentration of 137Cs, 151 ± 1 Bq/kg, was detected in muscle samples of perch from Redsjösjön lake. For uranium radionuclides and 226Ra uptake from water is the main source whereas for 210Po and 137Cs the uptake is controlled by the perch diet. Regarding naturally occurring radionuclides, the perch tended to accumulated uranium radionuclides in fins, gills, and skin; 226Ra in bones, fins and skin and 210Po in the organs linked to digestive system. Finally, in case of consumption, it is advised the consumption of skinned fillets of perch due to the higher bioaccumulation of the radionuclides investigated in the skin and scales.

Assessment of radiological impact on the surrounding environment and biota for phosphogypsum waste stockyard in Korean facility.

In this study, the effects of deposited gypsum residues on the surrounding environment and radiation exposure in plants and animals were evaluated under various exposure situations. A waste stockyard in a Korean facility (surrounded by mountains and sea) was used to store phosphogypsum, a byproduct of phosphoric acid processes, in a slurry form in a large gypsum storage facility (provided separately on the facility site). The ERICA tool was used to evaluate the impact of radiation on nonhuman environments for mineral processing and waste storage for risk estimation. The impact of radiation on the environment due to the phosphogypsum stockyard was negligible with a screening dose of less than 10μGyh-1. However, to conservatively evaluate the environmental impact of rain and wind in the phosphogypsum stockyard, the soil at the interface of the stockyard, where plants could not grow, was considered as an input value, and the estimated dose rate of shrubs was found to be 45μGyh-1. The effects of the phosphogypsum stockyard on the surrounding environment accounted for 95-100% of the total dose for internal exposure in biota. In general, radium was found to be the highest contributor to biota, and the next lead and polonium were contributors to the dose. The findings contribute to an understanding of the radiological impact of waste stored and disposed of at the facility on the environment and biota (all routes of exposure) and to developing sustainable operations and pollution monitoring policies.

Radioactivity and concomitant radiation dose from Malaysian herbal plants

Medicinal plants have been widely used in traditional treatment systems, food supplements, herbal remedies, and cultural practices. Medicinal plants uptake nutrients and radionuclides distributed in the environment and finally transfer them to the human body via various pathways, including plants-to-foodstuffs. It is important to assess the probable radiological impact of medicinal plants consumed for their therapeutic potential in Malaysia. In this study, for the first time, naturally occurring and artificial radionuclides in 14 different medicinal plants in Malaysia are quantified using HPGe gamma-ray spectrometry. The average specific activities for 226Ra, 228Ra, and 40K are found to be 5.42 ± 1.37, 3.81 ± 0.90, and 340 ± 13 Bq kg−1, respectively. The activity concentration of 137Cs is found to be 0.70 ± 0.18 Bq kg−1 only in the star anise sample. The estimated values have been compared with other reported data worldwide as well as the international advisory limits. All activity values are lower than the global average values compared. The values of the annual effective dose and associated excess lifetime cancer risk are lower than the acceptable limits prescribed by the United Nations Scientific Committee on the Effects of Atomic Radiation. Thus, consuming the evaluated herbal plants, which are considered radiologically safe for adult consumption, has no radiological impact. Future research on the radiological safety of human health obtained from medicinal plants and herbs may benefit from the baseline data provided by this study on the radioactivity in medicinal plants.

Assessment of radioactivity in particulate matter and soil from selected mining towns of Erongo region, Namibia

The presence of radionuclides in particulate matter (PM) associated with mining operations in communities located at the edge of the mine sites have been either greatly ignored or poorly understood, leading to the underestimations of the radionuclides concentrations in PM and health impact. In this study, measurements of radioactivity in PM and soil were made in the two mining towns of Karibib and Arandis to assess the human health radiological impact on the people around the mining sites. Dust fall samples were collected for a period of six months i.e. May 2017 to October 2017 using open bucket sampler procedure according to the American Society for Testing and Materials Standard Method (ASTM D1739) while some soil samples were collected using a soil auger. The samples were measured for the presence radionuclides using a well calibrated gamma-ray spectrometer coupled with a high purity germanium detector.In particulate matter samples, the mean activity concentrations of 226Ra, 238U, 232Th, 210Pb, and 40K were found to be 81.24±1.00, 57.99±2.61, 72.10±1.67, 55.89±6.21, 682±19.81 Bq.kg−1, respectively. Similarly, in soil samples, the mean activity concentrations were found to be 66.41±1.77 Bq.kg−1 for 226Ra, 52.79±3.40 Bq.kg−1 for 238U, 71.30±2.40 Bq.kg−1 for 232Th, Bq.kg−1 for 71.50±5.99 210Pb and 797.36±18.26 Bq.kg−1 for 40K. The activity concentrations revealed higher levels of radionuclides associated with the 238U series, which were distributed unevenly across the sites. The results were comparable to global values of 11 to 64 Bq.kg−1 for 238U, 17 to 60 Bq.kg−1 for 232Th, and 140 to 850 Bq.kg−1 for 40K.The activity concentrations were used to compute the absorbed dose (D), annual effective dose equivalent (AEDE), radium equivalent activity concentrations (Ra eq), external and internal hazard indices (H ex and H in), Gamma Index (Iγ), Alpha Index (Iα) and excess lifetime cancer risk (ELCR). The mean radiological parameters in most samples were found to be within acceptable limits, with Raeq 370 Bq.kg−1, which corresponds to an upper safe limit of AEDE of 1 mSv.yr−1, the prescribed safe limit by the International Commission on Radiological Protection (ICRP), and thus the potential radiological health effects may not be significant.

A Study on Radiological Hazard Assessment for Jordan Research and Training Reactor

Numerical simulations of atmospheric dispersion and dose assessment were performed for the Jordan Research and Training Reactor (JRTR) to evaluate its radiological effects on surrounding population and the environment. A three-dimensional atmospheric dispersion model was applied to investigate the behavior of the radionuclides released into the air, and a dose assessment model was used to estimate the radiological impact on the population residing in nearby cities around the JRTR. Considering full core meltdown an accidental scenario, most of the source term was assumed to be released from the JRTR. Simulations were performed to calculate the air and deposition concentrations of radioactive materials for July 2013 and January 2014. The monthly averaged values of concentrations, depositions, and dose rates were analyzed to identify the most harmful effects in each month. The results showed that relatively harmful effects occurred in January 2014, and the total annual dose rate was estimated to be approximately 1 mSv outside the 10 km radius from JRTR. However, the impact of a nuclear accident is not as severe as it might seem, as the affected area is not highly populated, and appropriate protective measures can significantly reduce the radiation exposure. This study provides useful information for emergency preparedness and response planning to mitigate the radiological consequences of a nuclear accident at the JRTR.

Sorption study of long-lived 94Nb on laterite: Effects of physicochemical parameters on sorption

Zr–Nb alloy is used as the pressure tube in pressurized heavy water reactors (PHWR). Prolonged neutron irradiation of the pressure tubes leads to the formation of a long-lived radioisotope 94Nb. Thus, the discharged pressure tubes possess huge 94Nb activity which persists for a prolonged period.If these discharged pressure tubes come in contact with ground water, 94Nb isotope may leach and migrate and this can lead to a long-term radiological impact in the environment.In the present study, we have explored the capability of laterite as a filler material for the containment and retarding the migration of 94Nb. In this regard, detailed characterization of the laterite soil was carried out using energy dispersive X-ray fluorescence (EDXRF), X-ray diffraction (XRD), fourier transform infra-red spectrometry (FTIR), total cation exchange capacity determination, zeta potential measurement and thermogravimetric analysis (TGA). The sorption study of 94Nb on laterite was carried and the effects of different physico-chemical parameters like pH, ionic strength, temperature and equilibration time were evaluated. Ionic strength, temperature and time dependent sorption studies assist to explore the probable sorption mechanism of 94Nb on laterite, which helps in understanding the migration behaviour of 94Nb in natural aquatic environment. This study suggests that laterite is a promising material in containment of 94Nb isotope owing to its good cation exchange behaviour in the acidic medium and ability to form surface complex in the neutral medium.