Relevance of radon progeny measurements for the assessment of inhalation doses in groundwater utilities.

The high radon concentrations measured in the indoor air of groundwater facilities and the prevalence of the problem have been known for several years. Unlike in other workplaces, in groundwater plants, radon is released into the air from the water treatment processes. During the measurements of this study, the average radon concentrations varied from 500 to 8800 Bq m-3. In addition, the indoor air of the treatment plants is filtered and there are no significant internal aerosol sources. However, only a few published studies on groundwater plants have investigated the properties of the radon progeny aerosol, such as the equilibrium factor (F) or the size distribution of the aerosol, which are important for assessing the dose received by workers. Moreover, the International Commission on Radiological Protection has not provided generic aerosol parameter values for dose assessment in groundwater treatment facilities. In this study, radon and radon progeny measurements were carried out at three groundwater plants. The results indicate surprisingly high unattached fractions (fp= 0.27-0.58), suggesting a low aerosol concentration in indoor air. The correspondingFvalues were 0.09-0.42, well below those measured in previous studies. Based on a comparison of the effective dose rate calculations, either the determination of thefpor, with certain limitations, the measurement of radon is recommended. Dose rate calculation based on the potential alpha energy concentration alone proved unreliable.

Geographical distribution of radon and associated health risks in drinking water samples collected from the Mulazai area of Peshawar, Pakistan.

Geospatial methods, such as GIS and remote sensing, map radon levels, pinpoint high-risk areas and connect geological traits to radon presence. These findings direct health planning, focusing tests, mitigation, and policies where radon levels are high. Overall, geospatial analyses offer vital insights, shaping interventions and policies to reduce health risks from radon exposure. There is a formidable threat to human well-being posed by the naturally occurring carcinogenic radon (222Rn) gas due to high solubility in water. Under the current scenario, it is crucial to assess the extent of 222Rn pollution in our drinking water sources across various regions and thoroughly investigate the potential health hazards it poses. In this regard, the present study was conducted to investigate the concentration of 222Rn in groundwater samples collected from handpumps and wells and to estimate health risks associated with the consumption of 222Rn-contaminated water. For this purpose, groundwater samples (n = 30) were collected from handpumps, and wells located in the Mulazai area, District Peshawar. The RAD7 radon detector was used as per international standards to assess the concentration of 222Rn in the collected water samples. The results unveiled that the levels of 222Rn in the collected samples exceeded the acceptable thresholds set by the US Environmental Protection Agency (US-EPA) of 11.1 Bq L-1. Nevertheless, it was determined that the average annual dose was below the recommended limit of 0.1 mSv per year, as advised by both the European Union Council and the World Health Organization. In order to avoid the harmful effects of such excessive 222Rn concentrations on human health, proper ventilation and storage of water in storage reservoirs for a long time before use is recommended to lower the 222Rn concentration.

5G NR launching in Greece: Preliminary in situ and monitoring network measurements of electromagnetic fields exposure levels at rooftops.

In Greece, 5G New Radio (NR) has started launching in the end of 2020, at the 3400-3800 MHz (FR1) frequency band. Focusing on 117 Base Stations (BSs) which were already equipped with 5G NR antennas, in situ broadband and frequency selective measurements have been conducted at minimum three points of interest, at adjacent rooftops (when accessible). The points have been selected according to the sweeping method and the electric field strength (E) value has been stored on the selected worst-case scenario point. Spectrum analysis was conducted in the FR1, for the allocated spectrum that corresponds to each mobile communication provider, in order to get preliminary results concerning the contribution of the 5G NR emissions in the general public exposure levels. The vast majority of the in situ measurements has been conducted in urban environments from the beginning of 2021 until the mid of 2022, since in Greece 5G NR services launching started from the big cities. Additionally, a 5G NR BS, installed in a suburban environment (in the city of Kalamata) is thoroughly investigated during its pilot and regular operation, based on broadband and frequency selective measurements data derived by the National Observatory of Electromagnetic Fields (NOEF) monitoring sensor network. In situ measurement data within the 5G NR frequency range are verified via the NOEF's output. The 5G NR contribution to the total E-field levels is assessed in time, from pilot to regular operation of the BS. In all cases, compliance with the reference levels for general public exposure is affirmed.

Natural Radioactivity in Raw Building Materials for Underground Parking Lots and Assessment of Radiological Health Risk for the Population.

This article reports the results of an investigation into the activity concentration of natural radionuclides in raw building materials for underground parking lots, together with the assessment of the radiation hazard for the public related to exposure to ionizing radiations. To this purpose, high-purity germanium (HPGe) γ-ray spectrometry was employed in order to quantify the average specific activity of 226Ra, 232Th, and 40K natural radioisotopes. With the aim to assess any possible radiological health risk for the population, the absorbed γ-dose rate (D), the annual effective dose equivalent outdoor (AEDEout) and indoor (AEDEin), the activity concentration index (I), and the alpha index (Iα) were also estimated, resulting in values that were lower than the maximum recommended ones for humans. Finally, the extent of the correlations existing between the observed radioactivity and radiological parameters and of these parameters with the analyzed samples was quantified through statistical analyses, including Pearson's correlation, a principal component analysis (PCA), and a hierarchical cluster analysis (HCA). As a result, three clusters of the investigated samples were recognized based on their chemical composition and mineralogical nature. Noteworthily, this paper covers a certain gap in science since its topic does not appear in literature in this form. Thus, the authors underline the importance of this work to global knowledge in the environmental research and public health fields.

Trends of occupational exposure to ionizing radiation in Central China for the period 2000-2021.

A retrospective analysis of occupational exposure to ionizing radiation from medical uses and industrial uses in the three provinces of Central China from 2000 to 2021 was conducted. The average annual effective dose in medical uses and industrial uses decreased from 2.042 mSv and 2.334 mSv in 2000-2002 to 0.476 mSv and 0.371 mSv in 2021 respectively; the fraction of monitored workers receiving annual dose not exceeding 1 mSv increased from 60.78% and 74.45% in 2000-2002 to 94.20% and 96.85% in 2021 respectively, while receiving annual doses exceeding 20 mSv declined from 1.35% and 1.91% in 2000-2002 to 0.18% and 0.03% in 2021 respectively. The average annual effective dose and NR20 in the period 2000-2021 were relatively high in professional public health institutions (0.955 mSv and 0.004) and hospitals (0.815 mSv and 0.004). In 2021, the average annual effective dose to monitored workers in different occupational categories in medical uses in the three provinces of Central China were in the range of 0.199-0.692 mSv, with interventional radiology received the highest dose and NR20 (0.692 mSv and 0.005); the average annual effective dose ranged from 0.161 to 0.493 mSv in industrial uses, with industrial radiography received the highest dose and NR20 (0.493 mSv and 0.001). Occupational exposure in medical uses and industrial uses declined obviously in Central China, and the groups receiving higher doses are the radiation workers working in hospitals and professional public health institutions, or engaged in interventional radiology, nuclear medicine and industrial radiography, warranting more effective radiation protection measures.

Development of methodology for identification and assessment of ecosystems with an underground source of tritium.

The article considers the issues of working out the suitable approaches for identifying zones with the presence of underground near-surface waters with increased concentrations of tritium discharged into a surface reservoir. The following methods were used as possible methods: determination of tritium content in snow cover, determination of tritium content in vegetation in the form of tritium of free water and organically bound tritium, determination of tritium content in river water and coastal vegetation. The studies were carried out at a previously identified site where groundwater with a tritium concentration of up to 6000 Bq/l is present, located in the vicinity of the city of Obninsk (Kaluga region, Russia). As a result of the conducted research, it was concluded that the analysis of the distribution of tritium in vegetation is an excellent methodological technique for identifying areas of location of near-surface underground waters contaminated with tritium. As a control parameter, both the concentration of tritium in the free water of plants and the content of organically bound tritium can be used. To detect underground tritium contamination the most promising use is the following indicator - the content of OBT in the shoots of woody plants. This parameter is very informative, and the sampling procedure for its determination has no seasonal restrictions, unlike such parameters as the content of tritium in grass and leaves, the content of tritium in snow cover, surface waters, which are preferably collected only in summer or winter. It should be noted that the control of surface waters of the groundwater discharge zone may not be a sufficiently informative indicator for identifying areas of polluted water inflow, since it depends on the ratio of the volumes of leaking polluted groundwater and the annual flow of the watercourse.

Levels of naturally occurring radioisotopes in local and imported bottled drinking water available in Québec City, Canada.

Consumption of local and imported bottled water in Canada has greatly increased during the past three decades. While the presence of natural radioactivity is often overlooked when dealing with the water quality of these bottled products, it could contribute substantially to the uptake of radionuclides especially when sourced from regions with higher radioactivity levels compared to where it is consumed. In this study, the activity of several naturally occurring radionuclides (i.e., 210Po, 226,228Ra, 230,232Th, 234,235,238U) were measured in bottled water available in Québec, Canada after sample pretreatment and analysis by either radiometric or mass spectrometry approaches. 230,232Th and 228Ra concentrations were below minimum detectable activity levels in all samples tested. Analytical results for 234U, 235U, 238U, and 226Ra showed concentrations that ranged from 0.38 to 115 mBq/L, (2.2-313) x 10-2 mBq/L, 0.48-58.4 mBq/L, and 1.1-550 mBq/L, respectively. 210Po was detected in only 5 samples and its activity ranged from 2 to 26 mBq/L. To determine variability in activity within brands, the same brands of bottled water were purchased during two consecutive years and analyzed. The possible radiological impact of the consumption of these types of water was assessed based on different drinking habit scenarios. Some of the imported water brands showed higher activity concentrations than local sources or tap water, suggesting that individuals drinking predominantly imported bottled water would receive a higher radiation dose than those who drink mainly local water.

The convergence approach may be critical to improving early situational awareness in hostile radioactive environments.

This study explores the impact of a simulated radiological dispersal device (RDD) event in an urban area on young adults around 20 years old. The RDD releases radioactive Cs-137 (7.0E+3 Ci), a common industrial sterilization source. The study aims to demonstrate that combining computational codes and epidemiological models can produce valuable data to guide initial actions when confronting a hostile radioactive environment. The HotSpot Health Physics and RESRAD-RDD codes were used in the simulation to evaluate the event's initial phase. The codes were executed together, and the HotSpot output data was input into RESRAD-RDD. Based on simulated radiation dose levels, estimated doses were incorporated into radioepidemiological models proposed by the Committee on Biological Effects of Ionizing Radiation (BEIR V or VII report). Despite limitations, data transfer between the models revealed no discontinuities or antagonisms. Radiation doses were simulated under three exposure conditions and two atmospheric release modes (day or night), suggesting that atmospheric conditions, sex, and exposure routine can strongly influence the perception of radiation impacts. This combination of methods can increase situational awareness and help with decision-making and developing coping strategies.

Use of air things radon detector in liquid samples (serum and urine).

This study involved the assessment of 222Rn concentrations in liquid samples (namely serum and urine) obtained from individuals who were smokers and non-smokers across five distinct age groups in the Najaf Governorate of Iraq. The measurements were conducted using a portable digital Air Things device commonly employed for detecting radon gas in residential environments. This device was placed in a container that is placed in liquid samples, which makes it work to capture the existing radon. The mean value of radon concentrations in serum and urine samples for smokers was 5.64 ± 2.80 Bq/m3 and 3.56 ± 2.31 Bq/m3, respectively. While, the mean value of radon concentrations in serum and urine samples for non-smokers was 2.32 ± 0.67 Bq/m3 and 1.61 ± 1.00 Bq/m3, respectively. By comparing the radon concentrations for serum and urine samples with age and smoking groups, the value of P-Value (p < 0.01) was increased significantly statistically. Also, it is found that a positive and good correlation for radon concentrations between serum and urine. Although the levels of radon were found to be under the globally accepted thresholds, the results of 222Rn in all samples of serum and urine in smokers were higher than in non-smokers. Thus, it may be concluded that cigarette smoking is used as a biomarker of the presence of radon gas.

Assessment of radiological hazards from radioactivity natural of cement used in Dwellings in Rio de Janeiro, Brazil.

Brazil is the fourth largest cement consumer in the world and the largest producer in Latin America, around 1.3% of global production. The main inputs in the manufacture of cement are limestone and clay. Few studies have been carried out in the country on the risk of these materials used in civil construction. Therefore, the objective of this present work is to evaluate the radiological danger that they can present to society. Gamma spectrometry analysis on 16 samples of different brands of cement used as construction material in Rio de Janeiro (Brazil) was performed in this study, using an HPGe detector and the Genie 2000 data acquisition software. Samples were set to count for an accumulation time of 14,400 s (4 h) and all measurements were corrected to eliminate background and backscattering. Activity concentrations are determined for 226Ra was from (41.2 ± 1.6 to 174.9 ± 3.9) Bq kg-1, 232Th was from (15.7 ± 0.5 to 43.1 ± 0.7) Bq kg-1 and 40K was from (82.6 ± 7.2 to 254 ± 17) Bq kg-1. To assess radiological health risks: mean values of Radium Activity Equivalent 150.0 ± 3.4 Bq kg-1, Annual Gonadal Dose Equivalent 468 ± 11 µSv year-1 and Lifetime Excess Cancer Risk (ELCR) 2.42 ± 0.06 were calculated. Total Absorbed Dose Rates ranged from 72.2 ± 1.7 to 225.1 ± 5.2 nGy h-1. The damage to collective health was also estimated from the annual effective dose rates with an estimated total cost of damage to health of US$ 130 million. Values are generally within global limits reported by UNSCEAR.

Radiological safety assessment for transportation of reactor pressure vessel during decommissioning of a nuclear power plant in Korea.

In Korea, decommissioning of nuclear power plants and transportation of the decommissioning waste are expected to expand in the near future. It is necessary to confirm that radiological risks to the public and workers are not significant through radiological safety assessment. The objective of this study is to assess the radiological safety for transportation of RPV waste, which is a major decommissioning waste with relatively high level of radioactivity. It was assumed that the waste would be transported to the Gyeongju disposal facility by land transportation. First, the source term and transportation method of the RPV waste were determined, and the external dose rates from the waste were calculated using MCNP. Then, transportation scenarios were assumed under both normal and accident conditions. Under the scenarios, radiation doses were calculated using the RADTRAN. Under normal operation scenarios without a transportation accident, assuming 40 shipments per year, the average individual doses for the public ranged from 6.56×10-6to 2.18×10-2mSv yr-1. The maximum individual doses for only a single shipment ranged from 2.43×10-6to 3.14×10-1mSv. For cargo handlers and vehicle crew members, the average doses were 2.26×101mSv yr-1and 2.95 mSv yr-1, respectively. Under transportation accident scenarios, average individual radiological risks which are product of the radiation doses and the annual accident rates ranged from 1.14×10-11to 1.61×10-10mSv yr-1by transportation route segment when considering the transportation accident rate. Average individual doses assuming transportation accident occurrence ranged from 2.62×10-4to 1.42×10-3mSv. The maximum individual dose under accident conditions was 7.99×10-2mSv. The calculated doses were below the regulatory limits in Korea. However, relatively high doses were observed for cargo handlers and vehicle crew members because of conservative assumptions. This study results can be used as basic data for the radiological safety assessment for the decommissioning waste transportation in the future.

Natural radionuclides and radiological risk assessment in the stream and river sediments of a high background natural radiation area Kanyakumari, India.

The Kanyakumari coast is known to be a high background natural radiation area due to the placer deposits of heavy minerals such as ilmenite, monazite, and rutile. The Kanyakumari river sediments that could be the source of the elevated amounts of natural radionuclides in the coastal sands have been studied in this paper. The activity concentrations of primordial radionuclides 226Ra, 232Th, and 40K were determined using high-purity germanium (HPGe) gamma-ray spectrometry. The mean activity concentrations of 226Ra, 232Th, and 40K were found to be 75 Bq kg-1, 565 Bq kg-1, and 360 Bq kg-1, respectively. The mean absorbed dose rate was 395 nGy h-1. Radiological hazard parameters were studied and compared with the world average values. The contribution of 232Th to the total dose rate was found to be higher than that of the two other radionuclides. The high mean ratio of 232Th/226Ra suggested an enrichment of 232Th and the occurrence of 226Ra leaching due to an oxidizing environment. Principal component analysis (PCA) was carried out for the radionuclides in order to discriminate the source of the sediments. This study provides new insights into the distribution of natural radionuclides in sediments of rivers and streams.

Assessment of radioactivity level and associated radiological hazard in riverbed samples within industrial areas.

Terrestrial gamma radiation is one of the major outdoor radiation exposures to the general public that varies substantially based on the type and geological properties of the soil. The objective of this study is to evaluate the naturally occurring radioactive materials (NORMs) distribution and assess the hazard parameters in the riverbank soil within various industrial zones in the densely populated Dhaka and Chattogram cities of Bangladesh. The mean activities of 226Ra (37 ± 3), 232Th (58 ± 4), and 40K (1129 ± 18) Bqkg-1 in the assessed soil samples were found to be slightly higher than the world average values 32, 35, and 420 Bqkg-1, respectively. The mean radium equivalent activity (207.49 Bqkg-1) and the external and internal hazard indices were within the recommended limits of 370 Bqkg-1 and <1, respectively. The mean absorbed dose rate (99.47 nGyhr-1), annual effective dose (0.12 mSva-1), ELCR (4.27 × 10-4), and gamma level index (1.58) exceeded the world average values 59 nGyhr-1, 0.07 mSva-1, 2.9 × 10-4, and 1 respectively. However, the studied areas are safe from a radiological viewpoint with no radiation health hazard to the people. The results of this study can be utilized to produce factual baseline data for future studies.

Using spectroscopic autoradiography of alpha particles for the quantitative mapping of 226Ra ultra-traces in geo-materials.

The measurement of 226Ra and the identification of 226Ra-bearing minerals are important for studying the behavior of radium in the environment. Various instruments for measuring 226Ra are currently used: among the radiometric techniques that measure in bulk (no spatialization), there are gamma spectrometers and alpha spectrometers. Other instruments such as SEM-EDS can map the chemical elements thus providing information on the distribution of 226Ra, but are limited for ultra-trace analyses on natural geomaterials. Finally, autoradiography techniques can locate radioactivity, but are limited to the identification of the contribution of 226Ra when the 238U series is complete. This study focuses on spectroscopic autoradiography, a method for measuring both the energy of the alpha particle emissions and their positions on the autoradiograph. A gas detector based on a parallel ionization multiplier technology was used for this purpose. Alpha particle energy is dependent on the emitting radionuclides. In order to track the 226Ra, the energy spectrum of the 238U series was studied with modeling software. It appears possible to apply a thresholding on the energy spectrum to discriminate the 226Ra from the first alpha emitters of the 238U decay chain (i.e. 238U, 234U and 230Th, all below 5 MeV). The developed method was applied to a U-mill tailing sample prepared as a thin section. The sample was heterogeneous in terms of radioactivity and was not at secular equilibrium with 238U, as expected. The 226Ra was identified and localized, and different regions of interest were also analyzed with SEM-EDS elements cartography. This revealed 226Ra-rich barite (BaSO4) phases measured at 3 ppmRa on average and containing no uranium; and uranium in siderite (FeCO3), showing a strong 226Ra deficit compared with secular equilibrium. Spectroscopic autoradiography opens up possibilities for the analysis of heterogeneous geological samples containing natural alpha emitters such as 238U and 226Ra: the 226Ra can be localized and quantified at ultra-trace content, and the method developed can also identify newly (young) uranium phases by measuring 238U/226Ra activity disequilibrium.

Influence of earthquake on radon exhalation law at the beach of the uranium tailing reservoir under high temperature environment.

In this paper, the influence of an earthquake on radon exhalation rate of uranium tailings reservoir beach under high temperature environment is studied by using a self-made integrated simulation test device for natural disasters, and a scale model test based on similarity and dimensional laws. The results show that, (1)When the peak acceleration reaches 0.6g, the radon exhalation rate increases sharply with the increase of peak acceleration, and tends to be gentle after 1.0g. (2)Under the action of high temperature, the radon exhalation rate increases rapidly with the increase of high temperature time, and gradually becomes flat after the 4th hour. (3)Compared with loading the earthquake condition only, the coupling effect of high temperatures and earthquakes causes a greater degree of damage to the beach surface of a uranium tailings reservoir under the same acceleration conditions, and the fissure rate and radon exhalation rate of the beach surface are substantially increased.

Environmental and mineralogical studies on the stream sediments of Baltim-El Burullus coastal plain, North Delta, Egypt.

This work is mainly concerned with the effect of anthropogenic activities and natural radioactivity due to the presence of highly radioactive black sand spots, factory construction, and shipping, in addition to other activities like agriculture on human beings. Forty samples were collected along Baltim-El Burullus coastal plain to detect the effect of these problems and determine the suggested solutions. The black sand of the Baltim-El Burullus coastal plain exhibits a considerable amount of economically heavy minerals, their ratio relative to the bulk composition in the investigated samples ranges from 3.18 to 10.5% with an average of 5.45%. The most important of them are magnetite, ilmenite, rutile, leucoxene, garnet, zircon and monazite. The existence of some radioactive-bearing accessory mineral deposits like zircon and monazite led to measuring the naturally occurring radionuclides 226Ra, 232Th and 40K to evaluate the excess lifetime cancer risk (ELCR). The results showed that these concentrations are 19.1 ± 9.73, 14.7 ± 9.53 and 211 ± 71.34 Bq kg-1 were lower than the corresponding reported worldwide average of 35, 45, and 412 Bq kg-1 for each radionuclide (226Ra, 232Th, and 40 K). The gamma hazard indices such as absorbed dose rate (Dair), the annual effective dose (AED), and excess lifetime cancer risk (ELCR) factor were computed in the investigated sediments and all the results were found (Dair = 26.4 nGy h-1, AED = 0.03 mSv year-1, ELCR = 0.0001) to be lower than the values suggested by the United Nations Scientific Committee on the effect of Atomic Research (59 nGy h-1, 0.07 mSv year-1 and 0.0029 for Dair, AED and ELCR, respectively). The study suggests that the black sand is safe to use in various infrastructure applications at Baltim-El Burullus coastal plain. The levels of radioactivity are not high enough to pose a risk to human health.

Comparison of atmospheric radionuclide dispersion models for a risk-informed consequence-driven advanced reactor licensing framework.

Current nuclear facility emergency planning zones (EPZs) are based on outdated distance-based criteria, predating comprehensive dose and risk-informed frameworks. Recent advancements in simulation tools have permitted the development of site-specific, dose, and risk-based consequence-driven assessment frameworks. This study investigated the computation of advanced reactor (AR) EPZs using two atmospheric dispersion models: a straight-line Gaussian plume model (GPM) and a semi-Lagrangian Particle in Cell (PIC). Two case studies were conducted: (1) benchmarking the NRC SOARCA study for the Peach Bottom Nuclear Generating Station and (2) analyzing an advanced INL Heat Pipe Design A microreactor's end-of-cycle inventory. The dose criteria for both cases were 10 mSv at mean weather conditions and 50 mSv at 95th percentile weather conditions at 96 h post-release. Results demonstrated that GPM and PIC estimated similar mean peak dose levels for large boiling water reactors in the farfield case, placing EPZ limits beyond current regulations. For ARs with source terms remaining in the nearfield, PIC modeling without specific nearfield considerations could result in excessively high doses and inaccurate EPZ designations. PIC dispersion demonstrated an order of magnitude higher estimate of nearfield inhalation dose contribution when compared to GPM results. Both models significantly reduced EPZ sizing within the nearfield. Thus, reductions in the AR source term may eliminate the need for a separate EPZ.

Assessment of radiation dose to people and wildife inhabiting the Grote Nete catchment in Belgium.

We evaluate the impact of the radiological contamination of the Grote Nete catchment in Belgium to people and non-human biota. This region has received effluents from the phosphate and nuclear industries via tributaries of the Grote Nete river in past decades, resulting in the presence of radionuclides such as 241Am, 60Co, 137Cs, 40K, 210Pb, 238Pu, 239,240Pu, 226Ra, 228Ra, 228Th, 232Th, 234U, 235U and 238U. During the period 2016-2021, we measured these radionuclides in the water column, the bed sediment and riverbanks. Additionally, we carried out radon measurements on the riverbanks in 2022. Based on these measurements, the dose rates to people were calculated for different potential exposure scenarios, using the SCK CEN biosphere tool. We also performed an assessment of exposure of ionising radiation to non-human biota (including 222Rn and its daughters) using the ERICA Tool. We observed three types of areas at the Grote Nete riverbank: (a) a lower category exposure with 226Ra concentrations reflecting purely Belgian background values; (b) a middle category with enhanced 226Ra, mainly adsorbed on clay minerals and (c) an upper category extending to maximum values in the order of 103 Bq kg-1. The main component of the dose rate for terrestrial and aquatic organisms is 226Ra followed by 210Pb (terrestrial) or 228Ra, (aquatic). The anthropogenic vector of the contamination (40K, 60Co, 90Sr, 137Cs, 228Th, 232Th, 234,235,238U, 238,239Pu, 241Am) makes a negligible contribution to dose. Overall, the Grote Nete wildlife is not under significant risk from exposure to soil or water-borne radionuclides and radon emanating from the soil, even if the ERICA benchmark of 10 µGy h-1 is occasionally exceeded for 226Ra, 210Pb or 228Ra, because exposures are below the levels at which effects are known to occur. For people, radon inhalation is the main exposure pathway and exposures can reach 1 mSv y-1 for hypothetical residents living at the riverbanks and remaining most of their time in the area, but it can be expected that exposures are much lower at increasing distances from the river. It is concluded that neither people nor the environment are at any significant radiological risk from this situation.

Assessment of indoor radon distribution and seasonal variation within the Kpando Municipality of Volta Region, Ghana.

This study uses CR-39 radon detectors to examine radon distributions, seasonal indoor radon variations, correction factors, and the influence of building materials and characteristics on indoor radon concentration in 120 dwellings. The study also determines the spatial distribution of radon levels using the ArcGIS geostatistical method. Radon detectors were exposed in bedrooms from April to July (RS), August to November (DS); December to March (HS), and January-December (YS) from 2021 to 2022. The result for the radon levels during the weather seasons were; 32.3 to 190.1 Bqm-3 (80.9 ± 3.2 Bq/m3) for (RS), 30.8 to 151.4 Bqm-3 (68.5 ± 2.7 Bqm-3) for HS and 24.8 to 112.9 Bqm-3(61.7 ± 2.1 Bqm-3) for DS, and 25.2 to 145.2 Bq/m3 (69.4 ± 2.7 Bqm-3). The arithmetic mean for April to July season was greater than August to November. The correction factors associated with this study ranged from 0.9 to 1.2. The annual effective dose (AE) associated with radon data was varied from 0.6 to 4.04 mSv/y (1.8 ± 0.1 mSv/y). The April to July period which was characterized by rains recorded the highest correlation coefficient and indoor radon concentration. Distribution and radon mapping revealed radon that the exposure to the occupant is non-uniformly spread across the studied dwellings. 15.4% of the studied data exceeded WHO reference values of 100 Bq/m3. The seasonal variation, dwelling age, and building materials were observed to have a substantial impact on the levels of radon concentration within the buildings.

Ambient dose equivalent rates of gamma radiation from natural radionuclides and 137Cs at grasslands and forests in the area of the Belarusian NPP in the pre-commissioning period (2019).

In situ gamma-spectrometric measurements were performed at grasslands (45 plots) and forests (6 plots) in the vicinity of the Belarusian nuclear power plant in September-October 2019. The aim of the study was to evaluate the baseline level of ambient dose equivalent rates of gamma radiation from natural radionuclides and 137Cs in the period preceding the commissioning of the NPP. The study revealed more than a 2-fold variability in values of the total ambient dose equivalent rate: from 29 to 72 nSv/h. This spread can be explained by variability in the content of natural radionuclides in the environment and, accordingly, ambient dose equivalent rate. At forest sites, compared to grassland sites, the values of ambient dose equivalent rates of gamma radiation from natural radionuclides were statistically significantly lower. The contribution of gamma radiation from 137Cs to the total ambient dose equivalent rate was insignificant and averaged 3% for grasslands and 6% for forests.