RESUMO
Meeting the requirement of high specific activity of radioisotopes and carrying out comprehensive research and development activities in the nuclear field, different nuclear facilities, including their waste disposal facilities, are going to be operational at Visakhapatnam, India. Due to environmental processes, the engineered disposal modules may lose their structural integrity and may release some radioactivity to the geo-environment. The subsequent migration of radionuclides reaching the geological environment will be governed by the distribution coefficient (Kd). Cs was chosen for the sorption study in two soil samples (soil-29 and 31) and to estimate the Kd in all the 40 soil samples through the laboratory batch method at the new campus of DAE, Visakhapatnam, India. Different soil chemical parameters like pH, organic matter, CaCO3, and cation exchange capacity were determined in 40 soil samples and their effect on Cs sorption was investigated. The effect of solution pH and initial concentration of Cs on sorption was also studied. The results show that the sorption of Cs increases with increasing pH. The Cs sorption was well explained by Freundlich and Dubinin-Radushkevich (D-R) isotherm models. Site-specific distribution coefficients (Kd) were also estimated and the values were found to vary from 75 ± 1 to 540 ± 12 L kg-1. The observed wide variation in Kd could be due to large variations in the physico-chemical properties of collected soil. The competitive ions effect study suggests that K+ has higher interference for Cs+ sorption as compared to Na+. The present study results will help assess the environmental impact due to Cs release in any unforeseen scenario and in planning effective remediation strategies.
Assuntos
Poluentes Radioativos do Solo , Poluentes do Solo , Adsorção , Monitoramento Ambiental , Poluentes Radioativos do Solo/análise , Poluentes do Solo/análise , Solo/química , ÍndiaRESUMO
On 29 September 1957, the so-called Kyshtym accident occurred at the USSR's first nuclear weapons plutonium production facility. The East Ural State Reserve (EUSR) was established in the most contaminated part of the radioactive trace, where a substantial part of the forests died in the first years after the accident. The purpose of our study was to evaluate the natural restoration of forests and to verify and update the taxonomic parameters that characterize the current state of forest stands in the EUSR. Data on the forest inventory of 2003 and results of our research of 2020 performed by the same methods on 84 randomly selected sites served as the basis for this work. We developed models to approximate growth dynamics and then updated the 2003 taxation-related forest data for the entire EUSR. According to these models and ArcGIS construction of new data, forest-covered lands make up 55.8% of the whole EUSR territory. The proportion of birch forests in the forest-covered lands is 91.9%; 60.7% of wood resources are located in mature and overmature (81-120-year-old) birch forests. The total timber stock in the EUSR is > 1385 thousand tons. It was revealed that ~ 4.2 × 1014 Bq of 90Sr is situated within the EUSR. The main stock of 90Sr is found in soils. The 90Sr stock in the stands is ~ 1.6-3.0% of the total content in the forests. Only a part of the EUSR forest stands can be used for practical applications.
Assuntos
Acidente Nuclear de Fukushima , Poluentes Radioativos do Solo , Monitoramento Ambiental , Poluentes Radioativos do Solo/análise , Florestas , Acidentes , Radioisótopos de Césio/análiseRESUMO
Tests of nuclear weapons, various radiation accidents have led to a significant contamination of the natural environment with technogenic radionuclides and an increase in the radiation load on humans and biota. The soil cover is a kind of depot that accumulates technogenic radionuclides, from where they can enter the body of animals and humans in various ways. The migratory abilities of radionuclides and their inclusion in biological chains are determined by the properties of the radionuclides themselves, the properties of the soil, as well as the mechanism of formation of radioactive contamination. A large number of nuclear tests and experiments of various types and capacities carried out at the Semipalatinsk Test Site (STS) led to the formation of various radioactive contaminated sites that differ from each other in nature, levels and isotopic composition. One of the most studied, from the point of view of studying the forms of presence, the solubility of radioactive particles, is the territory of the 'Experimental Field' testing ground, where ground and air tests were carried out. The specifics of the experiments, namely the interaction of the soil with the high-temperature explosion zone, led to the formation of slag surfaces and vitrified particles containing technogenic radionuclides, including 239+240Pu and 90Sr isotopes. Information on the presence of such sparingly soluble forms of radionuclides on the territory of other testing grounds of STS is extremely scarce. The resistance of radioactive particles to leaching by mineral acids can lead to an underestimation of the content in the soil cover of hazardous radionuclides, including 239+240Pu and 90Sr. Ultimately, this will lead to an underestimation of the radiation hazard for the population engaged in economic activities on the territory of the landfill (grazing, haymaking and mining) or living outside it. Chemical preparation of analyzed samples is one of the most time-consuming and critical stages, which limits the performance of the entire analysis as a whole, since even the highest performance measuring instruments cannot be realized with a lot of time spent on this procedure. Decomposition of samples in autoclaves is one of the alternative methods of sample preparation, but practically devoid of the disadvantages inherent in decomposition in open systems. The advantage of using autoclaves over decomposition in open systems is that the decomposition occurs in a closed volume of the reaction chamber at elevated pressure, which increases the boiling point of liquids and, accordingly, accelerates the decomposition of particles. Thus, sample digestion occurs in a shorter time, with fewer reagents and minimal analyte loss. The last factor, along with the completeness of the decomposition, is the main indicator that affects the quality of the analysis. In this paper, we consider the method of autoclave decomposition in the determination of technogenic radionuclides in soils of STS.
Assuntos
Monitoramento de Radiação , Poluentes Radioativos do Solo , Humanos , Solo , Monitoramento de Radiação/métodos , Poluentes Radioativos do Solo/análise , Radioisótopos/análise , DigestãoRESUMO
This paper presents the approach, assumptions, and computational analysis of the preliminary safety assessment, regarding the post-closure period for the disposal of radioactive waste in Greece. The assessment was implemented in the context of the National Program for the disposal of radioactive waste in the country, which is currently in the early stage for the investigation of facility siting. The basis scenario selected for this investigation was the leaching of radionuclides and the exposure in a residence offsite. Moreover, a scenario involving the intrusion in the facility and construction of a dwelling that disturbs the disposal zone is also considered. Due to the significant uncertainties in the current phase, the simulations related to leaching of the waste both in the offsite and intrusion scenarios are based on an uncertainty analysis with 25 site and scenario related parameters. The most important contribution is attributed to Ra-226 with an annual dose equal to about 2 and 3 µSv per MBq disposed, for the offsite and intrusion scenario, respectively. Th-232, Cl-36, C-14, Ag-108m and Pu-239 follow with a dose one order of magnitude less, compared to Ra-226. In the leaching scenarios examined, and for the most dose relevant radionuclides, the exposure related to drinking water from the well and the use of this water to irrigate fruits and vegetables are by far the dominant pathways due to the environmental transfer of the radionuclides and their associated dose coefficients. Th-232 dominates the direct exposure pathways (direct external radiation and plant contamination from the contaminated surface soil) in the intrusion scenario with an annual dose of about 1.4 mSv per Bq/g disposed. Ra-226, Cl-36 and Ag-108m cause exposure levels higher than 0.2 mSv/y per Bq/g disposed in the facility. A wide range was considered for the uncertainty parameters that led to a significant variation in the predicted doses that is expected to envelope the potential exposure for each radionuclide.
Assuntos
Plutônio , Monitoramento de Radiação , Resíduos Radioativos , Poluentes Radioativos do Solo , Resíduos Radioativos/análise , Plutônio/análise , Grécia , Poluentes Radioativos do Solo/análiseRESUMO
The isotopic signature of radionuclides provides a powerful tool for discriminating radioactive contamination sources and estimating their respective contributions in the environment. In this context, the 135Cs/137Cs ratio has been tested as a very promising isotopic ratio that had not been explored yet in many countries around the world including France. To quantify the levels of radioactivity found in the environment, a new method combining a thorough radiochemical treatment of the sample and an efficient measurement by ICP-MS/MS has been recently developed. This method was successfully applied, for the first time, to soil and sediment samples collected in France in two mountainous regions preferentially impacted either by global fallout from nuclear weapons testing (i.e., the Pyrenees) or by the Chernobyl accident (i.e., the Southern Alps). The 135Cs/137Cs ratios measured on twenty-one samples ranged from 0.66 ± 0.04 and 4.29 ± 0.21 (decay-corrected to January 1st, 2022) corresponding to the characteristic signatures of the fallout from Chernobyl and global fallout associated with the nuclear weapons testing, respectively. Moreover, large variations of both the 137Cs mass activity and the studied isotopic ratio recorded by most samples from the southern Alps suggest varying proportions of these two 137Cs sources. For these samples, the contribution of each source was estimated using this new tracer (135Cs/137Cs) and compared with the mixing contribution given by activity ratio: 239+240Pu/137Cs. This work has successfully demonstrated the applicability of the 135Cs/137Cs isotopic signature to nuclear forensic studies and could be extended to better evaluate the environmental impact of nuclear facilities (i.e., NPP, waste reprocessing).
Assuntos
Acidente Nuclear de Fukushima , Militares , Monitoramento de Radiação , Cinza Radioativa , Liberação Nociva de Radioativos , Poluentes Radioativos do Solo , Poluentes Radioativos da Água , Humanos , Poluentes Radioativos do Solo/análise , Espectrometria de Massas em Tandem , Monitoramento de Radiação/métodos , Radioisótopos de Césio/análise , Poluentes Radioativos da Água/análise , Cinza Radioativa/análiseRESUMO
This paper includes a review of the natural background radiation of the Kingdom of Saudi Arabia. The review deals with natural radioactivity measurements conducted in the past few decades in the Kingdom. The numerous research works reviewed refer to different materials soils processed building material, terrestrial (dwellings) and mining sites. For the measurements, different experimental techniques were adopted. The highest mean specific activity of 238U, 232Th and 40 K in soil samples was found to be 39.0, 25.6, and 343.0 Bq/kg, respectively. While the world average values are 33, 45 and 420 Bq/kg, respectively. For building materials, the highest mean values for 226Ra, 232Th and 40 K were 89, 106 and 773 Bq/kg, respectively. The mean indoor and outdoor dose rates were 455 µGy/y (Riyadh City) and 883 µGy/y (Al-Khamis City), respectively. For the mining sites the mean values for 238U, 226Ra, 228Ra, gross α and gross ß, were 0.12, 0.33, 21, 0.78 and 2.44 Bq/kg, respectively. Based on the available data it is concluded that most of the natural background radiation levels in the measured locations were within acceptable limits, while a few isolated locations showed elevated dose rates. This review suggests that new improved radiological survey methods be employed to cover the entire country, and that areas identified with comparably high dose rates be re-assessed, especially, in dwellings and mining sites.
Assuntos
Monitoramento de Radiação , Poluentes Radioativos do Solo , Arábia Saudita , Radiação de Fundo , Radiometria , Doses de Radiação , Poluentes Radioativos do Solo/análise , Tório/análiseRESUMO
The impact of low-dose-rate radiation on genetics is largely unknown, particularly in natural environments. The Fukushima Dai-ich Nuclear Power Plant disaster resulted in the creation of contaminated natural lands. In this study, de novo mutations (DNMs) in germ line cells were surveyed from double-digest RADseq fragments in Japanese cedar and flowering cherry trees exposed to ambient dose rates ranging from 0.08 to 6.86 µGy h-1. These two species are among the most widely cultivated Japanese gymnosperm and angiosperm trees for forestry and horticultural purpose, respectively. For Japanese flowering cherry, open crossings were performed to produce seedlings, and only two candidate DNMs were detected from uncontaminated area. For Japanese cedar, the haploid megagametophytes were used as next generation samples. The use of megagametophytes from open crossing for next generation mutation screening had many advantages such as reducing exposure to radiation in contaminated areas because artificial crossings are not needed and the ease of data analysis owing to the haploid nature of megagametophytes. A direct comparison of the nucleotide sequences of parents and megagametophytes revealed an average of 1.4 candidate DNMs per megagametophyte sample (range: 0-40) after filtering procedures were optimized based on the validation of DNMs via Sanger sequencing. There was no relationship between the observed mutations and the ambient dose rate in the growing area or the concentration of 137Cs in cedar branches. The present results also suggest that mutation rates differ among lineages and that the growing environment has a relatively large influence on these mutation rates. These results suggested there was no significant increase in the mutation rate of the germplasm of Japanese cedar and flowering cherry trees growing in the contaminated areas.
Assuntos
Desastres , Acidente Nuclear de Fukushima , Monitoramento de Radiação , Poluentes Radioativos do Solo , Árvores/genética , Monitoramento de Radiação/métodos , Poluentes Radioativos do Solo/análise , Radioisótopos de Césio/análise , JapãoRESUMO
The current study analyzed and interpreted airborne radiometric data from Ilesha's basement complex rock and its surroundings. At the surface, the concentrations of the most frequent primordial radionuclides notably K, elemental concentration of uranium eU, and elemental concentration of thorium eTh were measured. The weighted mean elemental and activity concentrations were 0.85%, 2.75 ppm, 10.22 ppm, and 267.54 Bq kg-1, 34.41 Bq kg-1, 41.51 Bq kg-1 for 40 K, 238U, and 232Th, respectively. The low concentration of 40 K was certainly due to the effects of weathering, kaolinization of granites, and pedogenesis activities. The abundance of uranium was ascribed to the availability of uranium minerals such as allanite, apatite, and sphene with accessories minerals, while that of thorium was due to minerals such as cheralite, thorite, uranothorite, thorianite, and uranothorianite with accessories minerals. The RPHR weighted mean 1.48 µWm-3 compared to the earth's crust mean between 0.8 and1.2 µWm-3 was higher due to significant presence of gneiss rocks in all the studied profiles. Radiological hazard, in particular, dose rates, external hazard index, internal hazard index, radium equivalent, annual gonadal dose, effective dose dispensed to various organs of the body were computed to determine the deleterious effects of rocks in the area. The weighted means of annual gonadal dose of 363.98 µSv y-1 and outdoor 0.91 × 10×3 and indoor 1.65 × 10-3 excessive life cancer risks were more than the global average 300 µSv y-1, 0.29 × 10-3 and 1.16 × 10-3. As a result, proper surveillance is required in the area in order to prevent epidemics occurrence in future.
Assuntos
Monitoramento de Radiação , Rádio (Elemento) , Poluentes Radioativos do Solo , Urânio , Monitoramento Ambiental , Tório/análise , Urânio/análise , Radioisótopos/análise , Minerais/análise , Rádio (Elemento)/análise , Radioisótopos de Potássio/análise , Poluentes Radioativos do Solo/análise , Espectrometria gama , Radiação de FundoRESUMO
Estimating any radioactivity released into the environment is critical for public health protection, particularly if the radioactivity can enter the food chain. In the present work, the activity concentration of natural radionuclides in the soil, water, plants, and fruits of four vegetable crops, namely cucumber, sweet pepper, hot pepper, and tomato, growing under greenhouse conditions has been measured using a High Purity Germanium (HPGe) Detector. The measured activity concentrations for 226Ra, 232Th, and 40K in the studied soil samples ranged from 4.7 to 6.8, 3.4 to 6.1, and 63.9 to 112.4 Bq kg-1, respectively, while in plants, they ranged from Not Detected (ND) to 15.2, ND to 3.4, and 495.1 to 1467.4 Bq kg-1, respectively. The measured activity concentrations for 40K in the studied fruit samples ranged from 967.1 to 1459.1 Bq kg-1, while 226Ra and 232Th were not detected. The Transfer Factor (TF) of 226Ra, 232Th, and 40K from soil to plants and fruits has been evaluated, and the results from soil to plants varied from ND to 2.5, ND to 0.8, and 6.0 to 19.2, while the results for 40K in fruits varied from 8.7 to 18.4, while 226Ra and 232Th were not detected.
Assuntos
Monitoramento de Radiação , Radioatividade , Poluentes Radioativos do Solo , Verduras , Monitoramento de Radiação/métodos , Poluentes Radioativos do Solo/análise , Produtos Agrícolas , SoloRESUMO
The nuclear power plant accident in Fukushima had led to pollution of forest ecosystems with 137Cs in 2011. In this study, we simulated the spatiotemporal distribution of 137Cs concentrations of litter layer in the contaminated forest ecosystems in two decades from 2011, which is one of the key environmental components of 137Cs migration in the environment due to the high bioavailability of 137Cs in the litter. Our simulations showed that 137Cs deposition is the most important factor in the degree of contamination of the litter layer but vegetation type (evergreen coniferous/deciduous broadleaf) and mean annual temperature are also important for changes over time. Deciduous broadleaf trees had higher initial concentrations in the litter layer due to the direct initial deposition on the forest floor. However, the concentrations remained higher than those in evergreen conifers after 10 years due to redistribution of 137Cs by vegetation. Moreover, areas with lower average annual temperatures and lower litter decomposition activity retained higher 137Cs concentrations in the litter layer. The results of the spatiotemporal distribution estimation of the radioecological model suggest that, in addition to 137Cs deposition, elevation and vegetation distribution should also be considered in the long-term management of contaminated watersheds, which can be informative in identifying hotspots of 137Cs contamination on a long-term scale.
Assuntos
Acidente Nuclear de Fukushima , Monitoramento de Radiação , Poluentes Radioativos do Solo , Ecossistema , Poluentes Radioativos do Solo/análise , Florestas , Radioisótopos de Césio/análise , JapãoRESUMO
Bangladesh is a rapidly developing country, which is vulnerable to various types of pollution due to the large-scale industrial and associated human activities that might potentially affect the locally harvested foodstuffs. Therefore, the transfer factor is an essential tool to assess the safety of foodstuffs due to the presence of natural radioactivity in environmental matrix and/or strata. This is a first study of its kind conducted in a well-known region for mango farming in Bangladesh, measuring the uptake of naturally occurring radioactive materials (NORMs) by grass and mango from soil to assess the ingestion doses to humans. The HPGe gamma-ray detector was used to determine the concentrations of NORMs in samples of soil (20), grass (10), and mango (10), which were then used to calculate the transfer factors of soil to grass and soil to mango. Average activity concentrations of 226Ra, 232Th, and 40K in associated soil samples (47.27 ± 4.10, 64.49 ± 4.32, 421.60 ± 28.85) of mango and 226Ra and 232Th in associated soil samples (45.07 ± 3.93, 52.17 ± 3.95) of grass were found to exceed the world average values. The average transfer factors (TFs) for mango were obtained in the order of 40K(0.80) > 226Ra (0.61) > 232Th (0.31), and for grass, it shows the order of 40K (0.78) > 232Th (0.64) > 226Ra (0.56). However, a few values (3 mango samples and 3 grass samples) of the estimated TFs exceeded the recommended limits. Moreover, Bangladesh lacks the transfer factors for most of the food crops; therefore, calculation of TFs in the major agricultural products is required all over Bangladesh, especially the foodstuffs produced near the Rooppur Nuclear Power Plant, which is scheduled to be commissioned in 2023.
Assuntos
Mangifera , Monitoramento de Radiação , Poluentes Radioativos do Solo , Humanos , Solo , Fator de Transferência , Bangladesh , Poaceae , Poluentes Radioativos do Solo/análise , Radioisótopos/análiseRESUMO
In this work, the variation of the radioactivity at different depth of the soil found at the Sung Valley in West Jaiñtia Hills District of Meghalaya in India is estimated by using the gamma-ray spectroscopy. The average activity concentration of 226Ra, 232Th and 40K for soil samples at different depths are measured to be 57, 156 and 352 Bq kg-1, respectively. The radiological hazard indices for the soil samples are calculated using standard models in order to determine the safe utility of these materials that are being used to manufacture domestic products by the locals. Values of all the radiological hazard indices are observed to be within the internationally recommended values as proposed by the European Commission and the United Nations Scientific Committee on the Effects of Atomic Radiation. The present study ensures that the soil analysed presents a negligible radiation hazard, and produced poetries and artefacts radiological incidence will stay within the allowed natural limit.
Assuntos
Monitoramento de Radiação , Radioatividade , Rádio (Elemento) , Poluentes Radioativos do Solo , Solo , Rádio (Elemento)/análise , Tório/análise , Poluentes Radioativos do Solo/análise , Radioisótopos de Potássio/análiseRESUMO
A systematic mapping of natural absorbed dose rate was carried out to assess the existing exposure situation in India. The mammoth nationwide survey covered the entire terrestrial region of the country comprising of 45127 sampling grids (grid size 36 km2) with more than 100,000 data points. The data was processed using Geographic Information System. This study is based on established national and international approaches to provide linkage with conventional geochemical mapping of soil. Majority (93%) of the absorbed dose rate data was collected using handheld radiation survey meters and remaining were measured using environmental Thermo Luminescent Dosimeters. The mean absorbed dose rate of the entire country including several mineralized regions, was found to be 96 ± 21 nGy/h. The median, Geometric Mean and Geometric Standard Deviation values of absorbed dose rate were 94, 94 and 1.2 nGy/h, respectively. Among the High Background Radiation Areas of the country, absorbed dose rate varied from 700 to 9562 nGy/h in Karunagappally area of Kollam district, Kerala. The absorbed dose rate in the present nationwide study is comparable with the global database.
Assuntos
Monitoramento de Radiação , Poluentes Radioativos do Solo , Poluentes Radioativos do Solo/análise , Solo , Índia , Dosímetros de Radiação , Radiação de Fundo , Doses de RadiaçãoRESUMO
The soil-to-orange fruit transfer factor of naturally occurring radionuclides was investigated. The temporal evolution of the three identified radionuclides, Ra-226, Th-232, and K-40, concentration was also examined throughout the growth period of the orange fruits until they reached maturity. A mathematical model was developed to predict the soil-to-fruit transfer of these radionuclides during the development of orange fruits. The results were found to agree with the experimental data. The experimental and modeling results revealed that the transfer factor for all radionuclides showed a similar exponential decline with the growth of the fruit and reached its minimum value when the fruit was ripe.
Assuntos
Monitoramento de Radiação , Poluentes Radioativos do Solo , Frutas/química , Fator de Transferência , Poluentes Radioativos do Solo/análise , Radioisótopos/análise , SoloRESUMO
The radioactive index value of the leachate of the uranium tailings dam is affected by the internal damage of the dam. Therefore, a way of using the deviation of the radioactive index concentration in the leachate to warn the instability of the dam is innovatively proposed in this paper. Firstly, the SSA-BP algorithm is used to predict and analyze the five groups of parameters U, Ra, ∑ α, ∑ ß and Rn. Then, the deviation between the actual value and the predicted value is computed. Finally, an early warning is given based on the entropy weight extension decision-making model. The model is verified by the leachate environment monitoring data of a uranium tailings dam in southern China from 2016 to 2020, which shows that the model can effectively caution of the instability of the uranium tailings dam and provides a reference for the subsequent decommissioning management.
Assuntos
Monitoramento de Radiação , Poluentes Radioativos do Solo , Urânio , Urânio/análise , Água , Poluentes Radioativos do Solo/análise , ChinaRESUMO
This work studied the spatial pattern of four natural radionuclides (226Ra, 228Ra, 228Th and 40K) as well as one artificial one (137Cs) in soils in the Chimborazo province (Ecuador), which belongs to the North Andes of South America. Soil samples were collected considering the Ecuador geological map. Statistical analyses showed that activity concentrations of 226Ra, 228Ra, 228Th do not exceed the worldwide average, while one geological unit exceeds the worldwide average for 40K. These high activity concentrations are attributed to radionuclide accumulation in plutonic and metamorphic rocks and also in ash resulting from eruptions of the Sangay volcano. The inverse distance weighted interpolation method was used to develop corresponding radioactivity maps where the highest activity concentrations are in the central-east of the studied area. In addition, a distribution pattern of 226Ra and 40K is observed in the geologies influenced by the presence of Chimborazo, Igualata, Tungurahua and Altar volcanoes. Spearman's nonparametric test shows positive correlations suggesting the presence of very homogeneous lithologies and that volcanic activities can influence the distribution of radionuclides in our environment. In seven of the samples, 137Cs was detected.
Assuntos
Monitoramento de Radiação , Radioatividade , Poluentes Radioativos do Solo , Solo , Poluentes Radioativos do Solo/análise , Monitoramento de Radiação/métodos , Radioisótopos de Césio/análiseRESUMO
In this research, examples of the fruits and vegetables cultivated in Kahramanmaras, 238U, 232Th, and 40K levels, were detected, and in the case of consumption of these vegetables and fruits, for several age categories (adults, children (10 years old), and infants), annually effective dose rates and lifetime cancer risks were calculated. In fruit samples, concentrations of 238U, 232Th, and 40K ranged from under detection limit (UDL) to 15.29 ± 1.14 Bq/kg, 0.30 ± 0.01 to 13.23 ± 1.60 Bq/kg, and 5.82 ± 0.21 to 179.82 ± 1.34 Bq/kg, respectively. The mean concentrations of 238U, 232Th, and 40K in fruit samples were 5.31 ± 0.44 Bq/kg, 2.72 ± 0.26 Bq/kg, and 56.84 ± 0.57 Bq/kg, respectively. In vegetable samples, concentrations of 238U, 232Th, and 40K ranged from 0.48 ± 0.04 to 11.77 ± 0.95 Bq/kg, 0.55 ± 0.04 to 4.57 ± 0.44 Bq/kg, and 9.32 ± 0.43 to 52.44 ± 0.52 Bq/kg, respectively. The mean concentrations of 238U, 232Th, and 40K in the vegetable samples were 6.58 ± 0.65 Bq/kg, 2.72 ± 0.27 Bq/kg, and 27.09 ± 0.27 Bq/kg, respectively. The mean annual effective dose rates for adults, children (10 years old), and infants in fruit samples were 0.184 ± 0.001 mSv/y, 0.288 ± 0.002 mSv/y, and 0.304 ± 0.003 mSv/y, respectively. The average lifetime cancer risks for adults, children (10 years old), and infants in fruit samples were 0.647 ± 0.006 × 10-4, 1.011 ± 0.010 × 10-4, and 1.067 ± 0.010 × 10-4, respectively. The mean annual effective dose rates for adults, children (10 years old), and infants in the vegetable samples were 0.118 ± 0.001 mSv/y, 0.128 ± 0.001 mSv/y, and 0.086 ± 0.001 mSv/y, respectively. The mean lifetime cancer risks for adults, children (10 years old), and infants in vegetable samples were 0.416 ± 0.004 × 10-4, 0.449 ± 0.004 × 10-4, and 0.304 ± 0.003 × 10-4, respectively.
Assuntos
Neoplasias , Monitoramento de Radiação , Radioatividade , Poluentes Radioativos do Solo , Adulto , Criança , Humanos , Verduras , Frutas/química , Turquia/epidemiologia , Radiação de Fundo , Monitoramento Ambiental , Neoplasias/epidemiologia , Poluentes Radioativos do Solo/análise , Radioisótopos de Potássio/análiseRESUMO
Radionuclides in environmental ecosystems have ecotoxicity and health impact on human and environment, so radioactive contamination has always been one of the global concerns. This study mainly focused on the radioactivity of mosses collected from the Leye Tiankeng Group in Guangxi. The activities of 239+240Pu measured by SF-ICP-MS and 137Cs measured by HPGe in moss and soil samples are as follows: 0-2.29 Bq/kg in mosses and 1.5-11.9 Bq/kg in soils for 137Cs, and 0.025-0.25Bq/kg in mosses and 0.07-0.51Bq/kg in soils for 239+240Pu. The range of 240Pu/239Pu atom ratios (0.201 in mosses and 0.184 in soils) and 239+240Pu/137Cs activity ratios (0.128 in mosses and 0.044 in soils) indicated that the 137Cs and 239+240Pu in study area were mainly contributed by global fallout. 137Cs and 239+240Pu showed similar distribution in soils. However, their behaviors in mosses were quite different due to the differences in the growth environment of mosses. The transfer factors of 137Cs and 239+240Pu from soil to moss varied in different growth stages and specific environments. A weak positive correlation among 137Cs, 239+240Pu in mosses and soil-derived radionuclides suggested that resettlement was predominant here. The negative correlation between 7Be, 210Pb and soil-derived radionuclides indicated that 7Be and 210Pb came from atmospheric components, while the weak correlation between them suggested that their specific sources were different. The Cu and Ni were moderately enriched in mosses here due to the use of agricultural fertilizers, At the same time, Zn was at a high level in the Lilang area, where transportation was more developed.
Assuntos
Briófitas , Plutônio , Monitoramento de Radiação , Radioatividade , Poluentes Radioativos do Solo , Humanos , Poluentes Radioativos do Solo/análise , Plutônio/análise , Ecossistema , Chumbo , China , Radioisótopos de Césio/análise , SoloRESUMO
Soil radon gas concentrations ranging from the detection limit up to 15 kBq/m3 were measured for the first time at the Kilbourne Hole maar in two selected regions: the first region was located on the western volcanic field, and the second was located inside the crater, near the southern border. Radioactive anomalies were found in association with the pyroclastic deposit, and the corresponding heat map provided information on the radon diffusion direction by the CRn gradient. It was observed for the first time that the anomalies found at the southern border are associated with a known geological fault, in opposition to what was found on the western border. The results provided by a radon activity concentration gradient of above (8 kBq/m3)/15 m suggest the existence of a fault that has not been detected yet. The observation that high levels near a dormant fault are related to tectonically enhanced radon was confirmed. The activity concentrations of Rn-gas were contrasted to existing gravimetric and magnetic data to provide measuring information on radon emanation, suggesting the existence of a high, naturally occurring radioactivity in the soil in the first place or an increased porosity of the locally defined lithology. The results indicated a higher correlation of 85% with magnetic anomalies. This is in opposition to the gravimetric data, which was only 30%. This study is a contribution to the characterization maar of volcanic geology by the soil radon activity index, which was designated as "low" in this case.
Assuntos
Poluentes Radioativos do Ar , Monitoramento de Radiação , Radônio , Poluentes Radioativos do Solo , Radônio/análise , Poluentes Radioativos do Solo/análise , Monitoramento de Radiação/métodos , Poluentes Radioativos do Ar/análise , Solo , Fenômenos MagnéticosRESUMO
The main purpose of this study was to determine the natural radioactivity level of raw radionuclides in the metal tailings of a mine in Lhasa, Tibet, and to conduct sampling and detection in 17 typical metal tailing mines in Lhasa, Tibet. The specific activity concentrations of 226Ra, 232Th, and 40K in the samples were calculated. The total αßχγ radiation, radon concentration, and outdoor absorbed dose rate in the air 1.0 m above the ground were measured. The γ radiation levels affecting miners and their surrounding residents were assessed. The results show that the radiation dose ranges from 0.08 µSv/h to 0.26 µSv/h, and the radon concentration ranges from 10.8 Bq/m3 to 29.6 Bq/m3, which does not exceed the national radiation-related standards, and the environmental hazard risk is low. The specific activity concentration of 226Ra ranged from 8.91 Bq/kg to 94.61 Bq/kg, the specific activity concentration of 232Th ranged from 2.90 Bq/kg to 89.62 Bq/kg, and the specific activity concentration of 40K was less than MDA to 762.89 Bq/kg. The average absorbed dose rate (DO) of the 17 mining areas was 39.82 nGy/h, the average annual effective dose rate (EO) was 0.057 mSv/y. The average external risk index of the 17 mining areas was 0.24, the average internal risk index was 0.34, and the average γ index was 0.31, all of which were less than the maximum permissible limit. This means that the metal tailings from all 17 mining areas were within the limit for γ radiation and, therefore, can be used in bulk as major building materials without posing a significant radiation threat to the residents of the study area.
