Radionuclide Concentrations Research Articles

Influence of the type of fuel used on the content of gamma radionuclides in the soot from the smoke ducts of the home furnaces

Abstract This paper presents the results of the measurements of gamma radioactive isotopes in soot samples from 15 different chimneys of household furnaces fired with various types of solid fuel. Soot samples were collected by the chimney sweep during the mandatory periodic cleaning of the chimneys. The γ-spectrometry technique using the high-purity germanium (HPGe) detector was employed for radiometry of the above-mentioned soot. It was found that the determined activity of gamma isotopes in soot is at a level similar to that in fly ash from power plants around the world. Artificial 137Cs was detected only in the soot from the combustion of biofuel or mixed fuel. The results obtained were chemometrically analyzed to find the relationship between the fuel used and the gamma isotope content in the soot. The analysis of 137Cs, 40K, 228Th, and 226Ra is sufficient to differentiate between the soot obtained and tested, and it varied with the fuel type burned (fossil fuels/biofuels).

Analysis of natural occurring radionuclide activity concentration of fish in west coast waters of Sabah, Malaysia

Abstract Fish is an important source of protein in human diets, but concerns arise due to natural radionuclide contamination in food and water sources. The study aimed to assess the concentration radionuclides activities (232Th, 238U, and 40K) in three commercial fish species from west coast waters of Sabah, Malaysia. Additionally, the annual effective dose and cancer risk for adults consuming these fish were evaluated. The concentration analysis was conducted using the inductively coupled plasma-mass spectrometer (ICP-MS) technique. The average concentration levels of radionuclide activity detected, and the annual effective dose was estimated to be much lower than UNSCEAR recommendations. The collective effective dose was estimated at 1.88 μSv y−1 for 232Th, 1.11 μSv y−1 for 238U, and 15.12 μSv y−1 for 40K. The cancer risk for adults from the annual effective dose was also found to be much lower than UNSCEAR and ICRP recommendations. Based on the study’s findings, consuming fish from west coast waters of Sabah is deemed safe. However, it is recommended to establish a long-term monitoring system for radionuclide bioaccumulation in fish to gather valuable information for assessing the potential health risks associated with radionuclides in Malaysia, particularly in the Sabah.

Radioactivity characteristics of lignite and hard coals: Case study of Zonguldak (Kozlu), Konya (Karapınar) and Antalya (Pamucakyayla) in Türkiye

Abstract In this study, the radioactivity contents of Carboniferous Zonguldak-Kozlu hard coals, Carboniferous Antalya-Pamucakyayla hard coals and Pliocene Konya-Karapınar lignites were determined, then compared with the limit values determined by the authorized institutions and their hazard indexes were determined. The range of measured activity concentrations was from 16.2 Bq·kg−1 to 227.6 Bq·kg−1 for 238U, 20.6 Bq·kg−1 to 67.5 Bq·kg−1 for 232Th and 211.9 Bq·kg−1 to 515.5 Bq·kg−1 for 40K. The calculated mean absorbed gamma dose rate (D), radium equivalent activity (Raeq) and annual equivalent dose (AED) were 105.7 nGy·h−1, 227.9 Bq·kg−1 and 129.6 μSv·h−1, respectively. Although 238U and 232Th radionuclide activity concentrations are comparable to literature values, 40K activity concentrations were around three or four times higher than in UNSCEAR (2000) reports. As it poses a radiological risk, it is necessary to take the necessary precautions to reduce the negative effects on the environment and human health due to use of coals from Konya-Karapınar, Antalya-Pamucakyayla basins and to burn in a controlled manner.

Physico-chemical, technological and radiological characteristics of kaolinized granite from northwestern Serbia

In the ceramic industry, the quality of the final ceramic tile as well as the possibility of its use depends on the quality and characteristics of the starting raw materials. One of the potential raw materials that can be used in the production of ceramic tiles is kaolinized granite, and it is necessary to examine its characteristics. In this research, the kaolinized granite of the Jadar block, northwestern Serbia, from the Beli Majdan surface mine, Jadranska Lešnica, was examined. Chemical analysis, X-ray diffraction analysis (XRD), and differential thermal analysis (DTA) were carried out. Ignition tests of the prepared composites were also conducted at three selected temperatures (1000, 1100, and 1250 °C), where total linear shrinkage and water absorption were determined. The activity concentrations of natural radionuclides and the artificial radionuclide 137Cs were determined using the gamma spectrometry method, and then the radiation risk for the external exposure of workers when working with this raw material was assessed. For the samples with the highest content of 226Ra, radon exhalation measurements were performed with the RAD7 device, and the values of the radon emanation coefficient were determined, as well as the values of alpha dose equivalents, which quantified the potential internal exposure of workers. The results of the chemical analysis showed that the content of Al2O3 in the examined composites ranged from 19.11 to 21.00%, and the content of Fe2O3 from 1.53 to 1.72%. Additionally, the K2O content in the tested composites ranges from 4.01 to 5.46%, which indicates the presence of K-feldspar and muscovite, and the Na2O content from 1.82 to 2.61%. Based on XRD analysis, it was established that the mineral composition of kaolinized granite includes quartz, feldspar, mica, calcite/dolomite, and kaolinite minerals. DTA analysis indicates the occurrence of minor endothermic processes at 488.05 °C and 558.12 °C, as well as an exothermic process at 980.8 °C. The color of the ignition is brick red to dark brown red. A trend of increasing linear shrinkage and decreasing water absorption with increasing ignition temperature was observed with the normal appearance of the samples. The average activity concentration of natural radionuclides are around and below the average values for building materials, expect for 40K. The values for 137Cs are below the values measured in soil. Annual effective doses estimated for external exposure are below 1 mSv y−1, which indicates that there is no increased radiation risk when working with this raw material. The values of the radon mass exhalation rate are in the range of 61–113 mBq kg−1 h−1, and the values of the radon emanation coefficient are 6.3–8.4%. The average value of the alpha dose equivalent is 1mSvy−1, which indicates a potential exposure to radon below 100 Bq m−3. Based on the obtained results, it can be concluded that kaolinized granite is a high-quality and radiologically safe raw material for making ceramic composites in the production of ceramic tiles. It has all the necessary characteristics to partially or completely replace feldspar in ceramic composites.

Assessment of natural radioactivity in soil samples along the coastal villages of Tirunelveli District, Tamilnadu, India using gamma-ray spectroscopy

ABSTRACT Natural radioactivity due to 238U, 232Th, and 40K in soil samples collected from coastal villages of Tirunelveli district, Tamilnadu was measured using a gamma-ray spectrometer. The activity concentrations of radionuclides in soil samples varied in the range of 5.45 to 263.30 Bq/kg for 238U, 72.56 to 1244.26 Bq/kg for 232Th, and 352.82 to 1751.41 Bq/kg for 40K respectively. The mean value of the radiological parameters like radium equivalent activity (549 Bq/kg), the annual effective dose rate indoor and outdoor (1.20 mSvy-1 and 0.30 mSvy-1), external and internal hazard indices (1.50 and 1.74) were estimated. All the radiological parameters exceed the world average values.

Assessment of Natural Radioactivity and Associated Radiological Indicators in Water and Surface Soils Around Beta Glass Plc and Its Environs, Ughelli, Delta State, Nigeria

A radiometric assessment was conducted around Beta Glass plc using sodium iodide detector (3×3-inch NaI (TI)). The study collected 14 soil and 13 water samples from June to July 2022, analyzing radioactivity concentrations of 40K, 238U, and 232Th. The mean specific activity concentrations of 40K, 238U, and 232Th were 184.00±29.73 Bqkg-1, 14.55±2.50 Bqkg-1, and 8.60±1.04 Bqkg-1, respectively, in soil samples, but these elements' concentrations in water were 27.429±5.633 BqL-1, 6.661±1.421 BqL-1, and 2.518±0.361 BqL-1, respectively. The average activity concentrations of 40K, 238U, and 232Th were lower than the safe limit, and the corresponding radiation hazard indices for soil samples were all below the UNSCEAR-recommended acceptable limits. The mean activity concentrations of radionuclides in water samples were higher than the UNSCEAR's recommended international limits for 40K, 238U, and 232Th. Nonetheless, elevated radiological health hazards imply that cumulative dosages may cause cancer, even though these values might not pose an immediate health concern to the local community's people or the workforce.

Spatial distribution of NORMs concentrations and assessing potential risk to inhabitants in western Chattogram, Bangladesh

ABSTRACT This study represents a pioneering endeavour in consolidating previous measurements of naturally occurring radioactive materials (NORMs) within the Chattogram division, Bangladesh. Employing a meticulous approach, data was overlaid onto a comprehensive grid map covering the entire Chattogram region, comprising 523 grids, each of 8.05 km x 8.05 km. The analysis revealed numerous areas where NORMs concentrations had not been previously measured. To bridge this gap, soil samples were collected from 56 previously unmeasured locations across Cumilla and Chandpur districts and analysed using high purity Germanium (HPGe) detector technology. Results indicated average activity concentrations of Ra-226, Th-232, and K-40 at 27.30 ± 5.41, 46.09 ± 7.88, and 362.50 ± 48.10 Bq.kg−1 respectively, with no detectable presence of Cs-137 or other anthropogenic radionuclides, affirming the region’s absence of fallout or accidental releases. Additionally, measured values for radiation hazard indices are well within acceptable limits set by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). Spatial distribution maps of radionuclide concentrations and absorbed dose rates were generated not only for the immediate study area but also for the entire Chattogram division, integrating previously collected data for the first time. These distribution maps, alongside the comprehensive findings of this study, establish a pivotal dataset for future research and regulatory efforts, providing invaluable insights into the region’s radiological landscape.

Dynamics of 137Cs content in higher aquatic plants of Kyiv and Kaniv Reservoirs

The study aimed to determine the temporal parameters of 137Cs specific activity in higher aquatic plants of Kyiv and Kaniv reservoirs. Parameters characterizing the dynamics of 137Cs content for hydrophytes (Potamogeton perfoliatus and Ceratophyllum demersum) and helophytes (Phragmites australis and Typha angustifolia) were determined based on the results of 137Cs specific activity determination in the aboveground plant organs. Plant samples were collected in 1989–2021 from a polygonal area in the upper part of Kyiv reservoir (shallow waters near Strakholyssia village) and in 2000–2021 from a polygonal area in the middle part of the Kaniv reservoir (shallow waters near Rzhyschiv and the Borispol islands). A model of specific activity of aquatic organisms was substantiated (or developed) in case of exponential decrease in radionuclide levels in the environment. The main parameter of the model is the period of resulting halving of organism specific activity due to the decrease in radionuclide concentration in water, its irreversible fixation in bottom sediments, and radioactive decay. During 1989–2021, the half-life period of 137Cs specific activity in Potamogeton perfoliatus, Ceratophyllum demersum, and Phragmites australis of Kyiv reservoir was 5.4 years. Two time intervals were identified, characterized by different intensities of radionuclide specific activity decrease. During the periods of 1989–1996 (1998), the specific activity of 137Cs in the studied plant species decreased by half in approximately 2 years. For the time interval of 2011(2012)–2021, the half-life period of 137Cs content in Potamogeton perfoliatus and Ceratophyllum demersum increased on average to 12 years. A tendency towards a slowdown in the rate of specific activity decrease was observed for Phragmites australis. During 1987–1996, the half-life period of maximum 137Cs specific activity in higher aquatic plants of Kaniv reservoir was 2.1 years. Thus, during the first decade after the accident, the rates of 137Cs content decrease in plants of Kyiv and Kaniv reservoirs did not differ. In 2000–2021, the rate of 137Cs specific activity decrease in Potamogeton perfoliatus and Ceratophyllum demersum of Kaniv reservoir corresponded on average to a half-life period of about 20 years. For Phragmites australis and Typha angustifolia, only a tendency to decrease in 137Cs activity was noted, corresponding to a half-life period of about 40 years. Over time, the half-life period of 137Cs specific activity in higher aquatic plants of Kyiv and Kaniv reservoirs increases, which is explained by the slowdown in the rate of decrease in volumetric activity of 137Cs in the waters of the Dnipro and Pripyat rivers. A model of 137Cs specific activity in higher aquatic plants of reservoirs for periods exceeding 20 years after accidental radionuclide entry into ecosystems of large plain reservoirs has been proposed. The parameters of the model describing the dynamics of 137Cs specific activity can be used for predictive assessments of 137Cs content in higher aquatic plants in the event of accidental radionuclide entry into ecosystems of large plain reservoirs.

Concentration level of radionuclides in road dust in the urban atmosphere of two cities of Pakistan

This research focused on measuring the concentration of particulate matter (PM2.5) aerosols and radionuclides (226Ra, 232Th, and 40K) in road dust collected using glass fiber filters from busy roads and populated areas in Islamabad and Rawalpindi, Pakistan. The measured concentrations ranged between 551.0 and 2025.7 µgm−3 for PM2.5 aerosols, 32.4 and 54.7 mBqm−3 for 226Ra, 15.8 and 26.8 mBqm−3 for 232Th, and 239.0 and 316.4 mBqm−3 for 40K. The study found that PM2.5 levels surpassed the WHO’s recommended limit of 25 µgm−3. Additionally, concentrations of 226Ra and 232Th were considerably higher than the global average values of 1 and 0.5 µBqm−3, respectively, in dust. The total inhalation effective dose in all samples exceeded the ICRP’s acceptable limit of 2 mSvy-1, except in the infant and 1-year-old age groups (considering F, M, and S-type modes). Notably, 232Th was identified as the primary contributor, accounting for 36.5 % to 99.4 % of the total inhalation effective dose.

Features of the accumulation of pollutants in plant feed and their translocation into the milk of cows

One of the sources of toxic substances entering the human body may be a valuable food product as milk. The intensity of exposure of ecotoxicants to milk of cows is determined by a number of factors, among which the main one is feed. The purpose of the research was to study the characteristics of the accumulation of heavy metals and radionuclides in plant feed, and their translocation from rations of cows into milk. The research was carried out in agricultural enterprises of the Shchuchansky district of the Kurgan region. In order to obtain the most complete information about the degree of contamination of the studied objects, the area was divided into fi ve zones taking into account the geographical location such as northern (Peschanskoye village), southern (Sukhoborskoye village), western (Beloyarskoye village), eastern (Petrovskoye village) and central (Chumlyak village) zone. The content of heavy metals in the feed and milk of cows was determined such as copper, zinc, cadmium, lead and radionuclides such as strontium-90 and cesium-137. The features of the accumulation of heavy metals and radionuclides depending on the type of feed as well as the dependence of the concentration of toxic substances in the ration on their amount in feed have been established. Regression equations have been calculated to predict changes in the concentration of heavy metals and radionuclides in the daily ration depending on their content in feed. The coeffi cients of translocation of heavy metals and radionuclides from the ration into the milk of cows during the stall and pasture periods were determined, which showed the absence of a connection between the presence of ecotoxicants in feed and milk. The maximum degree of contamination of rations was observed in the northern zone. The dependence of the concentration of toxic substances in the ration on their amount in feed has been established. No relation was found between the content of heavy metals and radionuclides in the rations and milk of cows. As the toxicity of the ration increased, the transfer coeffi cient of ecotoxicants decreased. During the pasture period, the transition coeffi cient was higher than during the stall period. The obtained research results would make it possible to regulate the intake of toxic elements into livestock products by selecting the components of the ration.

Natural Radionuclides Concentrations and Associated Radiation Hazard of Some Building Rocks Used in Taiz City, Yemen

Building materials comprise a diverse range of natural rocks that contain varying mineral components including radionuclides. Gamma spectrometry-based high-purity Germanium detectors were utilized to measure the activity concentrations of natural radionuclides: Radium-226 (226Ra), Thorium-232 (232Th), and Potassium-40 (40K) in various building rock samples found within and surrounding Taiz city. The activity concentrations of 226Ra, 232Th, and 40K vary from 27.79 ± 0.77 to 234.49 ± 3.13 Bq.kg-1, 25.82 ± 0.40 to 415.31 ± 2.47 Bq.kg-1, and 457.91±2.61 to 1139.56 ± 5.43 Bq.kg-1 with overall average value of 71.55 Bq.kg-1, 93.87 Bq.kg-1, 966.88 Bq.kg-1 respectively, these values were higher than the permissible thresholds. Furthermore, several radiation hazard indices were estimated including the radium equivalent (Raeq), the external hazard index (Hex), the internal hazard index (Hin), the gamma level index (Iɤ), the dose rate(Dɤ), the annual effective dose equivalent (AEDE), the excess lifetime cancer risk (ELCR), and the annual gonadal dose equivalent (AGDE). The findings illustrated that Basalt rocks have the minimum values of radiation hazard indices while the Himatite rocks have the maximum values of radiation hazard. The average values of radiation risks for most of building rocks fall below the recommended limits for safety. Based on the Radiation hazard indices of building rock samples, it can be concluded that with the exception of hematite rocks, all the examined rocks are considered safe for use in construction materials and pose non-significant radiation risks. The awareness about natural radioactivity levels of building rocks is critical for planning and performing strategies in radiation safety of buildings.

Estimation of annual effective radiation dose and cancer risk due to tea consumption

The current study aims to assess the radioactive health risks and their levels due to tea consumption. Fresh tea leaves were plucked from different locations in the Gumero tea farmland in Ilubabour zone, Ethiopia. High-resolution gamma-ray spectroscopy was used to measure the activity concentrations of artificial and natural radionuclides (e.g., 40K, 232Th, and 238U) in the samples. Radiological indicators such as committed dose rate (DR) and excess lifetime cancer risk, LCR (i.e., the cancer death risk due to lifetime exposure to carcinogens, ignoring the contribution of natural background risk) were evaluated to ascertain the radioactive risk to humans in the tea samples. DR and LCR, two radiological markers, were assessed to determine the radioactive risk to humans in the tea samples. The finding shows that the radiological hazards assessment of 238U and 232Th revealed that the Gumero tea leaves have natural radioactivity levels within the internationally recommended limit, while that of 40K was higher than the limit. Comparing the current study with other studies, it was found that the yearly effective doses and nuclide radioactivity concentrations in tea leaves were similar.

Gross alpha/beta and radionuclide activity concentrations in soil, plant and some fruits around the Tehran Research Reactor

Human activities usually have some contamination as effluents from chemical industries and radionuclides from nuclear reactors. For assessing the probable radioactive contamination in vicinity of Tehran Research Reactor, The gross alpha and beta radioactivity concentrations in soil, pine and cedar leaves and some selected fruits (fig, apple, berry and pomegranate) were investigated using an alpha/beta spectrometer during 2021–2022. Also, the concentrations of artificial and natural radionuclides in samples were investigated by the method of gamma spectroscopy. The gross alpha activity concentrations in soil, pine and cedar leaves and some selected fruits samples are from 0.05 to 0.35 Bq/gr and 0.07–0.31 Bq/gr and 0.04–0.18 Bq/gr, respectively. The gross beta activity concentrations in soil, pine and cedar leaves and some selected fruit samples are from 0.73 to 4.25 Bq/gr and 0.21–3.97 Bq/gr and 1.01–2.71 Bq/gr, respectively. Average activities concentration of natural radionuclide 232Th, 238U and 40K in soil, pine and cedar leaves and some selected fruits are 31.89–16.23–582.73 Bq/kg and 1.84–0.99–84.60 Bq/kg and 1.98–1.09–72.08 Bq/kg respectively. From artificial radionuclides, just 137Cs is recognized in soil sample and the range of 137Cs concentration in surface soils was observed to vary in the range 0.85–2.21 (Bq/kg). The result showed that the Tehran Research Reactor activities not have increased the environmental radioactivity and radiation level in the area.

Radionuclide Transfer in Tea Cultivation: Assessing Radiological Risks in the Largest and First Established Tea Garden in Bangladesh

ABSTRACT To address potential health risks associated with radioactivity in tea consumption, a study was conducted utilizing high purity germanium (HPGe) γ-ray spectrometry to measure the concentrations of 226Ra, 232Th, 40K, and 137Cs radionuclides in soil and tea leaves collected from several major tea gardens (including the Malnicherra tea garden which is the largest and first established tea garden in the Indian subcontinent) situated in Sylhet, Bangladesh. Although nearly all soil samples showed the presence of 137Cs (with a maximum activity of 6.5 ± 1.31 Bq/kg), none of the analyzed tea leaf samples exhibited its presence, which can be attributed to its restricted transferability from soil to plants. The range of transfer factors for 226Ra, 232Th and 40K from soil to tea leaves was calculated to be (0.39–0.54), (0.25–0.46) and (1.39–3.03), respectively. The heightened concentrations of 40K identified in the tea leaf samples can be mainly ascribed to specific metabolic processes associated with potassium, along with the heightened utilization of potassium chloride-based fertilizers aimed at enhancing tea production. The examination of hazard parameters, including the estimated committed effective dose and the excess lifetime cancer risk associated with tea consumption, reveals values that are comparatively lower than the recommended limits. Consequently, the radiation exposure from tea consumption does not present a significant radiological health concern for the general population.

RADIATION AND ECOLOGICAL STUDIES OF VEGETATION OF LUTSK DISTRICT OF VOLYN REGION

Abstract. The content of radionuclides of 137Сs, 90Sr and heavy metals in vegetation and agricultural products was found out in the settlements of Lutsk district of Volyn region. The results of our own field expeditionary research, as well as the results of generalization of stock materials of the Laboratory of Ecological Land Safety and Product Quality of the Volyn branch of the state institution “Institute for Soil Protection of Ukraine” (Lutsk) are the basis of the research. The plant products contain a small content of radioactive elements in the settlements of the Lutsk district of the Volyn region. The greatest pollution of plant products was found in the settlements of Sytnytsia and Omelіano. The content of the 137Сs, 90Sr does not exceed the maximum permissible concentrations. Exceeding the maximum permissible concentrations for the content of heavy metal salts was found in potatoes in the villages of Pozharky, Vesele. The results of the radiation-ecological study can be taken into account for the optimization of nature management and are necessary for state emergency management bodies of natural-technogenic content, for the possibility of reasonable planning and effective implementation of measures and projects for strengthening ecoenvironmental safety. The data obtained are important for the development of the National Concept to overcome the consequences of the Chernobyl disaster on the contamination of agricultural products with radionuclides and heavy metals.

Natural radioactivity level in Yemen: A systematic review of radiological studies

This paper aimed to conduct a systematic review of 26 published articles from 13 different regions in the Republic of Yemen related to the study of natural radioactivity (NORM) and enhanced artificial radioactivity (TENORM). The study relied on the analysis of various sample types, including air, groundwater, surface water, hot spring water, soil, sand, rocks, building materials, and oil field samples. It also analyzed the study areas, the types of detectors employed, and the study's timeframe. The analytical results raised significant concerns regarding the high levels of radioactivity observed in many of the studied regions. Moreover, some regions indicated the absence of any prior radiological study, despite apparent effects on the population and the environment, which suggest the presence of potential radionuclide concentration. Based on this study, it is strongly recommended that researchers conduct further radiological studies in regions previously studied over extended periods and in areas where no prior radiological studies have been conducted to assess potential radionuclide concentration.

Calibration of buried NaI(Tl) scintillator detectors for natural radionuclide measurement based on Monte Carlo modelling

Measurements of naturally occurring concentrations of 40K, and of the decay series of 238U and 232Th, are of interest in the earth sciences in general, and in particular, scintillator-based gamma spectrometers can be used for the low cost determination of burial dose rates in natural geological samples. We are currently developing a robust, portable, wireless detector specifically intended for field measurement of natural radionuclide concentrations and hence, the calculation of dose rates. One of the challenges in developing and applying such an instrument is reliable calibration. Most calibrations of field instruments depend on access to non-finite matrices of known K, U, Th activity concentrations, in either a 4π or 2π geometry; these are only available at a few facilities around the world. Here we investigate an alternative approach, based on the measurement of small samples containing well-known activity concentrations of only K or U or Th, and Monte-Carlo radiation transport modelling to convert the observed spectra into those expected from specific activity concentrations in a non-finite 4π geometry. We first validate our modelling procedure by simulating these observed spectra. The non-finite matrix calibration spectra are then predicted, and least-squares fitted to the spectrum observed at the centre of a 1 m3 of granite chips; the resulting predicted U, Th and K activity concentrations are compared with independently known values.

Seasonal Fluctuations in the Concentration of Natural Radionuclides in Groundwater of Al Dhahirah Governorate, Oman

Seasonal Fluctuations in the Concentration of Natural Radionuclides in Groundwater of Al Dhahirah Governorate, Oman

The characteristics of the vertical distribution of radionuclide in free troposphere from simplified release scenarios: a case study

Dose estimation in the upper air is not studied as much as on ground level or in boundary layer. However, there is a need from stakeholders in aviation industry for a reasonable estimation of the radioactive plume impact at cruising levels. This study aims to provide a quantitative estimation of the dose and how reliable it is for dispersion processes up to seven days. A Lagrangian atmospheric dispersion model is used to estimate quantitively the vertical extension of radionuclides from simplified hypothetical radionuclide release scenarios. Sources at different latitudes are selected for simulation in a boreal winter case. Three meteorological data are examined to test the sensitivity of vertical plume distribution to driving meteorological data. The vertical distribution of air concentration of radionuclides is investigated and the associated uncertainties are analysed. It is found that the vertical extension of plumes is sensitive to meteorological data being used where vertical turbulent velocities play an important role. It is therefore necessary to address the uncertainties of air concentration or dose in the free troposphere and caution must be taken when providing the results to stakeholders.

Field-based soil-plant uptake measurements of natural radionuclides for key vegetables and ghaf leaves in Abu Dhabi

With the thriving fossil fuel and nuclear based industries in the nation, radioecology has become necessary for the radiation safety and emergency-preparedness for the United Arab Emirates (UAE). Environmental radiation transport modelling in the UAE and the Arabian Peninsula are severely limited, as we discuss in this paper, due to lack of experiments specific to arid desert climates. To fill the missing gaps in the baseline arid region radioecological database, especially for the soil-plant uptake studies, rigorous field works have been conducted for the first time on the soil and plant in the farms and open fields of the UAE. We present Abu Dhabi based measurements of activity concentrations of radionuclides of natural origins, in soils, key vegetables (cucumber, tomato, and bell pepper), and leaves of ghaf - a prominent native tree. The empirical data are utilized to get the first published estimates of UAE-specific plant-soil concentration ratios (CR), measuring root uptake of radionuclides in nonleafy vegetables and native trees. Such systematic studies are very rare for arid sandy soils. For the 27 samples analyzed, the activity concentrations' (unit Bq kg−1) ranges are: 169–1746 for 40K, 12–19.5 for 226Ra, and 2.7–23.1 for 228Ra. Likewise, wide variability is seen in the averages of concentration ratios also, ranging in 1.05–4.94 for 40K, 0.14–1.82 for 226Ra, and 0.53–2.78 for 228Ra. A net bioaccumulation (concentration ratio >1) of some of these natural radionuclides is found in many samples, but no significant doses or hazard indices are found due to these three radionuclides in the UAE's soils and vegetations. The paper discusses the careful work through tens of field sampling exercises, well controlled sample processing, high resolution gamma spectrometry, and treatment of data from gamma counting rates to accumulated dose rate estimations.