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1.
J Environ Radioact ; 273: 107382, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38266319

RESUMO

Advances in the development of gamma-ray spectrometers have resulted in devices that are ideal for use in conjunction with the increasingly reliable systems of autonomously flying uncrewed aerial vehicles (UAVs) that have recently become available on the market. Airborne gamma-ray spectrometry (GRS) measurements have many different applications. Here, the technique is applied to a former uranium mining and processing site, which is characterized by relatively low specific activities and, hence, low count rates, requiring relatively large detectors and correspondingly big size UAVs. The future acceptance of the use of such UAV-based GRS systems for radionuclide mapping depends on their ability to measure absolute specific activities of natural radionuclides such as U-238 in near-surface soil that are consistent with the results of established and proven ground-based systems. To determine absolute specific activities on the ground, the gamma radiation data from airborne detectors must be corrected for attenuation caused by the flight altitude above ground. In recent years, mathematical procedures for altitude correction have been developed, that are specifically tailored to the working range of several tens of meters typical for UAVs. However, very limited experimental validation of these theoretical approaches is available. A very large dataset consisting of about 3000 UAV-based and 19,000 backpack-based measurements was collected at a low-grade uranium ore dump in Yangiabad, Uzbekistan. We applied different geostatistical interpolation methods to compare the data from both survey techniques by upscaling backpack data to airborne data. Compared to backpack systems, UAV-based systems have lower spatial resolution, so measurements average over larger areal units (or in geostatistical terminology: "spatial support"). Taking into account the change in spatial support, we illustrate that (1) the UAV-based measurements show good agreement with the upscaled backpack measurements and that (2) UAV surveys provide good delineation of contrasts of the relatively smooth U-238 specific activity distribution typical for former uranium mining and processing sites. We are able to show that the resolution of UAV-based systems is sufficient to map extended uranium waste facilities.


Assuntos
Monitoramento de Radiação , Poluentes Radioativos do Solo , Urânio , Urânio/análise , Monitoramento de Radiação/métodos , Poluentes Radioativos do Solo/análise , Espectrometria gama
2.
Radiat Prot Dosimetry ; 199(2): 95-106, 2023 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-36426758

RESUMO

In this present study, the activity concentration of the naturally occurring radionuclides 238U, 232Th and 40K have been measured in commonly used chemical fertilizers for agriculture by using gamma-ray spectrometry with NaI (TI) detector. Radiological hazard parameters have been calculated for samples. The mean specific activity concentration of the 238U, 232Th and 40K is 176, 5.75 and 4136 Bq kg-1, respectively. Particularly, the mean value of 238U, as well as 40K, is higher than the world recommended value. Also, the average value of radium equivalent activity is 503 Bq kg-1 and the absorbed dose rate (DR) is 282.93 nGyh-1, which is greater than the permissible limit, whereas the annual effective dose rate (AEDR) is 0.316 mSvy-1, which is lower than the world recommended value. Therefore, collected fertilizer samples significantly increase the activity concentration of natural radionuclides in the agricultural soils. Multivariate statistical techniques such as Pearson correlation and factor analysis are carried out for radioactive variables to understand the existing relationship between them. From obtained results reveals that these fertilizer samples increases the probability of adverse health effects due to natural radioactivity.


Assuntos
Monitoramento de Radiação , Rádio (Elemento) , Poluentes Radioativos do Solo , Urânio , Tório/análise , Fertilizantes/análise , Urânio/análise , Radioisótopos de Potássio/análise , Radioisótopos/análise , Poluentes Radioativos do Solo/análise , Agricultura , Rádio (Elemento)/análise
3.
Chemosphere ; 285: 131444, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34265714

RESUMO

In this study, several natural radionuclides (40K, 238U, 235U, 228Ac) and their decay product were investigated in various invertebrate and vertebrate fossils. In the high radioactivity group of fossils, 238U and 235U concentrations increased from 141 to 3621 Bq/kg and from 5.4 to 167 Bq/kg, respectively. In the low radioactivity group of fossils, concentrations of both U isotopes increased from 4.6 to 51 Bq/kg and from 0.18 to 2.3 Bq/kg, respectively. High radioactivity has been linked to the phosphatization process that affected the uranium sorption. Scanning of electron microscope images and X-ray fluorescence analysis were used to confirm the mode of preservation of studied fossils and the presence of a correlation between the phosphorus content and uranium elements in fossil specimens.


Assuntos
Monitoramento de Radiação , Radioatividade , Poluentes Radioativos do Solo , Urânio , Fósseis , Poluentes Radioativos do Solo/análise , Espectrometria gama , Tório/análise , Urânio/análise
4.
Chemosphere ; 283: 131098, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34144289

RESUMO

Naturally occurring radioactive elements depend on lithology geogenic characteristics, such as depositional, environmental, or diagenetic. Thus, evaluating these elements constitutes a tool to define ionizing radiation effect from rocky sequences. This study carried out in the Rancheria Sub-Basin establishes both characterization and assessment of this kind of material, known as NORM. The sampling included uranium-238, thorium-232, potassium-40, radon-226, and radon-222 in soil samples, cutting samples from the Molino-1 well, and radon in surface water. Bases on a radiometric methodology with a gamma-ray spectrometer for uranium-238, thorium-232, and potassium-40 and emanometric with ionizing chambers for radio-226 and radon-222. The analysis and results of the activity concentrations in soil samples of U-238, Th-232, K-40, and Ra-226 are 11.7 BqKg-1, 33.0 BqKg-1, 424.5 BqKg-1, and 15.59 BqKg-1, respectively, among the acceptable global averages. However, in some areas, observed values indicate high activity concentrations of U-238, Th-232, K-40, Ra-226, and Rn-222 in the soil of 50.2 BqKg-1, 62.8 BqKg-1, 1596.3 BqKg-1, 44.25 BqKg-1, and 112546.79 Bqm-3, respectively. Those activity concentrations were associated with zone lithology.


Assuntos
Monitoramento de Radiação , Radônio , Poluentes Radioativos do Solo , Urânio , Radioisótopos de Potássio/análise , Radônio/análise , Solo , Poluentes Radioativos do Solo/análise , Tório/análise , Urânio/análise
5.
Chemosphere ; 283: 131221, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34182624

RESUMO

The present study evaluates the enrichment and distribution of radioelements along the eastern coast of India. India possesses the second largest reserve of thorium bearing monazite in the world, in terms of heavy minerals present primarily along its long coastline. Radioelement estimation of about 30 km long beach area along the eastern coast of India is reported and implications discussed. A total number of 822 data points were studied using a portable Geiger Muller counter, to estimate the variation of dose rates, due to the ambient radionuclides along two different trends. One was parallel (northeast-southwest) and the second one perpendicular to the coastline. Pre-selected samples from in-situ radiometric surveys on the heavy mineral placers were studied further, for quantitative estimation of the abundance of radioactive elements primarily uranium and thorium, using a High Purity Germanium detector. Radioelement concentration assessment of core samples (depth ~2 m), were studied from two different beaches. Radiological parameters like radium equivalent, annual effective doserate and absorbed dose rate has been calculated based on the 238U, 232Th and 40K concentrations. Heavy mineral placers along the shoreline indicate a very high thorium (avg - 2990.22 Bq kg-1) which is due to the extensive distribution indicative of monazite. The coastal area also exhibits relatively low uranium (avg - 319.1 Bq kg-1). Based on its high thorium concentration, the area can be considered as a high natural background radiation area. Based on the concentrations of uranium and thorium, the weathering conditions and depositional environment prevalent along the beach areas have been discussed.


Assuntos
Monitoramento de Radiação , Rádio (Elemento) , Poluentes Radioativos do Solo , Urânio , Radiação de Fundo , Índia , Radioisótopos de Potássio/análise , Rádio (Elemento)/análise , Poluentes Radioativos do Solo/análise , Espectrometria gama , Tório/análise , Urânio/análise
6.
Materials (Basel) ; 14(3)2021 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-33494137

RESUMO

Supplementary cementitious materials (SCMs) in industrial waste and by-products are routinely used to mitigate the adverse environmental effects of, and lower the energy consumption associated with, ordinary Portland cement (OPC) manufacture. Many such SCMs, such as type F coal fly ash (FA), are naturally occurring radioactive materials (NORMs). 226Ra, 232Th and 40K radionuclide activity concentration, information needed to determine what is known as the gamma-ray activity concentration index (ACI), is normally collected from ground cement samples. The present study aims to validate a new method for calculating the ACI from measurements made on unground 5 cm cubic specimens. Mechanical, mineralogical and radiological characterisation of 28-day OPC + FA pastes (bearing up to 30 wt % FA) were characterised to determine their mechanical, mineralogical and radiological properties. The activity concentrations found for 226Ra, 212Pb, 232Th and 40K in hardened, intact 5 cm cubic specimens were also statistically equal to the theoretically calculated values and to the same materials when ground to a powder. These findings consequently validated the new method. The possibility of determining the activity concentrations needed to establish the ACI for cement-based materials on unground samples introduces a new field of radiological research on actual cement, mortar and concrete materials.

7.
J Environ Radioact ; 227: 106460, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33217620

RESUMO

The intention of the study was to establish the activity concentrations and the annual committed effective dose due to ingestion of medicinal plants and soils by pregnant women and their probable effects to infants. The samples of medicinal plants and soils were collected from Osukuru, Tororo District (Uganda). The naturally occurring radionuclides investigated were 226Ra, 232Th and 40K and their activity concentrations were determined using NaI gamma detector. In the medicinal plants, the average activity concentrations of 226Ra, 232Th and 40K were found to be 6.04 Bq/kg, 9.65 Bq/kg and 359.59 Bq/kg respectively. African Basil registered the highest activity concentration of 226Ra of 10.02 Bq/kg, spider plant had the highest activity concentration of 232Th of 18.60 Bq/kg whereas the pumpkin registered the highest activity concentrations of 40K of 437.92 Bq/kg. The average activity concentrations of 226Ra, 232Th and 40K in 'medicinal soils' were 68.87 Bq/kg, 78.20 Bq/kg and 477.44 Bq/kg respectively. The soils from the anthills registered the highest activity concentration of 226Ra and 40K while the one from bricks registered the highest activity concentration of 232Th. The annual committed effective dose due to the ingestion of medicinal plants varied from 0.096 to 0.297 mSv/y with an average of 0.194 mSv/y in infants, 0.016-0.040 mSv/y with an average of 0.029 mSv/y for individuals of age range 12-17 years and 0.007-0.018 mSv/y with an average of 0.013 mSv/y for individuals older than 17 years. Whereas the annual committed effective dose due to the ingestion of 'medicinal soils' varied from 1.28 to 1.65 mSv/y with an average of 1.46 mSv/y in infants, 0.23-0.30 mSv/y with an average of 0.26 mSv/y (12-17 years) and 0.07-0.09 mSv/y with an average of 0.08 mSv/y for individuals older than 17 years. In medicinal plants, the annual committed effective dose for the all age groups examined were below 0.3 mSv/y (maximum world permissible as reported UNSCEAR, 2000) while that due to the ingestion of 'medicinal soils' had values higher 0.3 mSv/y in infants. The results of this study show that there is inherent danger to the infants in consuming soils during pregnancy and this should be discouraged.


Assuntos
Plantas Medicinais , Monitoramento de Radiação , Rádio (Elemento) , Poluentes Radioativos do Solo , Adolescente , Criança , Feminino , Humanos , Radioisótopos de Potássio/análise , Gravidez , Gestantes , Radioisótopos/análise , Rádio (Elemento)/análise , Solo , Poluentes Radioativos do Solo/análise , Espectrometria gama , Tório/análise , Uganda
8.
Appl Radiat Isot ; 168: 109489, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33288398

RESUMO

Alpha-particle spectrometry, gamma spectrometry and neutron activation analysis techniques for determination of Th and U in environmental samples have been compared. The analytical parameters studied include detection limit, accuracy, repeatability, reproducibility and surrogate recovery. The results show that neutron activation analysis technique has the best accuracy among the studied techniques; the other two techniques were assessed relative to it. The percentage difference between the three techniques results is about [-20, 20]. In addition, U and Th concentrations are generally overestimated by gamma spectrometry and alpha-particle spectrometry in all cases except Th concentration in the former technique, which is underestimated.


Assuntos
Partículas alfa , Análise de Ativação de Nêutrons/métodos , Poluentes Radioativos/análise , Espectrometria gama/métodos , Tório/análise , Urânio/análise , Limite de Detecção , Monitoramento de Radiação/métodos , Radiometria/métodos , Reprodutibilidade dos Testes , Síria
9.
Int J Radiat Biol ; 96(8): 1028-1037, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32394771

RESUMO

Purpose: Ayurveda is one of the oldest systems of medicines in the world being practiced widely in the Indian subcontinent for more than 3000 years, and still remains as one of the important traditional health care systems. The Ayurvedic drugs are derived primarily from various parts of the plants, like root, leaf, flower, fruit or plant as a whole. Plants uptake minerals and other nutrients from the soil through their root system. Along with other minerals radionuclides present in the growing media also reach to the plant parts following the same pathway. Realizing the probable health hazards via the intake of Ayurvedic drugs, it is important to assess the concentration of natural radionuclides in commonly used medicinal plants.Materials and methods: NaI(Tl) scintillator-based gamma-ray spectrometry has been used to determine the activity concentrations of primordial radionuclides (226Ra, 232Th and 40K) in the most commonly used medicinal plant parts as ingredients of Ayurvedic medicines in India.Results and discussion: The average specific activity (Bqkg-1) of 226Ra, 232Th and 40K was found to be 43 ± 18, 36 ± 15[Formula: see text] and 230 ± 46, respectively. The estimated annual committed effective doses due to the intake of common Ayurvedic medicines at prescribed dosage was found to be 39 ± 16 µSv y-1,[Formula: see text] which is quite low as compared with the radiation dose limit of 1 mSvy-1 from all natural sources, reported by the International Commission on Radiological Protection (ICRP-60).Conclusions: It is found categorically that intake of Ayurvedic medicines at normal dosage poses no radiological hazard to the individual. Present results are significant in the wake of myths that many hazardous materials including radioisotopes are present at higher levels. Obtained results also serve as a reference information for the distribution of radionuclides in medicinal plant species.


Assuntos
Ayurveda , Plantas Medicinais/química , Radioisótopos/análise
10.
Environ Sci Pollut Res Int ; 27(13): 15856-15868, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32095961

RESUMO

This work presents results obtained using gamma spectrometry measurements of phosphogypsum samples on a non-fractionated (native) and fractionated phosphogypsum byproduct. The phosphogypsum was divided into particles size fractions within the range of < 0.063, 0.063-0.090, 0.090-0.125, 0.125-0.250, and over 0.250 mm and analyzed after reaching radioactive equilibrium using high-resolution gamma spectrometry technique. It was found that there is no significant differentiation between 226Ra distribution among particular grain size fractions of this material; however, tendency for preferential retention of radionuclides in particular grain size fractions is observed. The detailed analysis of results revealed that radium is preferentially retained in smaller grain size fractions, whereas lead and thorium in coarse fractions. The results indicate that overall 226Ra activity concentrations between particular fractions of phosphogypsum vary globally between - 34 and + 47% regarding non-fractionated material, and for 210Pb activity concentration, fluctuations are found between - 26 up and + 38%. Presumably, the mechanism of radium incorporation into gypsum phase is based on a sequence of radium bearing sulfate phases formation followed by a surface adsorption of these phases on the calcium sulfate crystals, whereas for lead and thorium ions, rather incorporation into crystal lattice should be expected as more likelihood process.


Assuntos
Rádio (Elemento)/análise , Poluentes Radioativos do Solo/análise , Urânio/análise , Sulfato de Cálcio , Fósforo , Radioisótopos , Tório/análise
11.
Appl Radiat Isot ; 149: 142-151, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31063963

RESUMO

Gamma-ray spectrometry is applied to estimate equivalent uranium (eU), equivalent thorium (eTh), and K% of 748 rock samples collected from Syrian territory. The spectrometry results are used to evaluate and map the radioactive heat production (HP) of Syria. A new approach involving the multifractal technique with the concentration-number model (CN) and log-log plots was originally proposed and hence applied in this paper to map the distribution of uranium concentration and HP of Syria. This approach helps us to differentiate different eU and HP ranges related to different litho-types. The advantages of proposing and applying the fractal technique are that the boundaries of the distinguished radioactive ranges of eU and HP coincide well with the lithological boundaries, which gives this technique superiority over other traditional statistical methods. The fractal CN model with the use of log-log plots proves its efficacy in differentiating between several eU and HP populations that are related directly to the geology of Syrian territory. The fractal model shows four threshold break points corresponding to uranium concentrations of 3.1, 7.38, 16.6, and 28.8 ppm and an HP of 0.715, 1.86, 3.63, and 6.26 µW/m3, respectively. The highest HP ranges are mainly related to the phosphatic deposits, characterized by the highest uranium content.


Assuntos
Temperatura Alta , Monitoramento de Radiação/métodos , Geologia , Poluentes Radioativos do Solo/análise , Espectrometria gama/métodos , Síria , Tório/análise , Urânio/análise
12.
J Environ Radioact ; 169-170: 203-208, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28142060

RESUMO

In this study the commonly used f-value for the 1001.03 keV (0.835 ± 0.004%) energy transition of the 234mPa was re-evaluated due to an obvious consistent overestimation of the 238U activity concentration. Different calibration protocols, samples' matrices and geometries, and gamma-ray spectrometers were exploited in order to assure the accuracy of the derived data. An average positive relative bias of about 24% from the currently used f-value was estimating leading to newly adopted f-value of 1.037 ± 0.052%. This newly suggested f-value will lead to an improvement in the accurate assessment process of the 238U using gamma-ray spectrometry in both environmental and nuclear safeguard fields.


Assuntos
Poluentes Radioativos/análise , Espectrometria gama/métodos , Urânio/análise , Calibragem
13.
J Environ Radioact ; 167: 1-12, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27914775

RESUMO

The Atomic Minerals Directorate for Exploration and Research (AMD) has conducted high-resolution airborne gamma ray spectrometer (AGRS), magnetometer and time domain electromagnetic (TDEM) surveys for uranium exploration, along the northern margins of Cuddapah Basin. The survey area includes well known uranium deposits such as Lambapur-Peddagattu, Chitrial and Koppunuru. The AGRS data collected for uranium exploration is utilised for estimating the average absorbed rates in air due to radio-elemental (potassium in %, uranium and thorium in ppm) distribution over these known deposit areas. Further, portable gamma ray spectrometer (PGRS) was used to acquire data over two nearby locations one from Lambapur deposit, and the other from known anomalous zone and subsequently average gamma dose rates were estimated. Representative in-situ rock samples were also collected from these two areas and subjected to radio-elemental concentration analysis by gamma ray spectrometer (GRS) in the laboratory and then dose rates were estimated. Analyses of these three sets of results complement one another, thereby providing a comprehensive picture of the radiation environment over these deposits. The average absorbed area wise dose rate level is estimated to be 130 ± 47 nGy h-1 in Lambapur-Peddagattu, 186 ± 77 nGy h-1 in Chitrial and 63 ± 22 nGy h-1 in Koppunuru. The obtained average dose levels are found to be higher than the world average value of 54 nGy h-1. The gamma absorbed dose rates in nGy h-1 were converted to annual effective dose rates in mSv y-1 as proposed by the United Nations Scientific Committee on the Effect of Atomic Radiation (UNSCEAR). The annual average effective dose rates for the entire surveyed area is 0.12 mSv y-1, which is much lower than the recommended limit of 1 mSv y-1 by International Commission on Radiation protection (ICRP). It may be ascertained here that the present study establishes a reference data set (baseline) in these areas to assess any changes in gamma radiation levels due to mining and milling activities in future.


Assuntos
Radiação de Fundo , Monitoramento de Radiação/instrumentação , Poluentes Radioativos do Solo/análise , Espectrometria gama , Urânio/análise , Índia , Mineração , Monitoramento de Radiação/métodos
14.
Appl Radiat Isot ; 126: 191-193, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28034510

RESUMO

For the ultimate sensitivity in trace radiochemical analysis, the radiation detector must have high efficiency and low background. A low-background gamma-ray spectrometer in regular use at NIST for over twenty years is being supplemented by a new system, improved in several ways. The new detector is much larger, a shield of iron reduces cosmic neutron background compared with lead, large plastic scintillators reduce the muon continuum background, and a digital data acquisition system gives new opportunities for optimization.

15.
Environ Pollut ; 215: 273-279, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27213569

RESUMO

To evaluate the state of the environment in Kopaonik, a mountain in Serbia, the activity concentrations of (4) K, (226)Ra, (232)Th and (137)Cs in five different types of environmental samples are determined by gamma ray spectrometry, and radiological hazard due to terrestrial radionuclides is calculated. The mean activity concentrations of natural radionuclides in the soil are higher than the global average. However, with an exception of two sampling locations, the external radiation hazard index is below one, implying an insignificant radiation hazard. Apart from (40)K, content of the natural radionuclides is predominantly below minimum detectable activities in grass and cow milk, but not in mosses. Although (137)Cs is present in the soil, grass, mosses and herbal plants, its specific activity in cow milk is below minimum detectable activity. Amongst the investigated herbal plants, Vaccinium myrtillus L. shows accumulating properties, as a high content of (137)Cs is detected therein. Therefore, moderation is advised in consuming Vaccinium myrtillus L. tea.


Assuntos
Radioisótopos de Césio/análise , Leite/química , Plantas/química , Poluentes Radioativos do Solo/análise , Chá/química , Vaccinium myrtillus/química , Animais , Bovinos , Monitoramento Ambiental , Feminino , Sérvia , Espectrometria gama
16.
Braz. arch. biol. technol ; 59: e16150666, 2016. tab, graf
Artigo em Inglês | LILACS | ID: biblio-951356

RESUMO

The aim of this study is to determine the amounts of radionuclides' activity present in samples of feed for young and adult chicken and feed for dairy and beef cattle, as well as in dicalcium phosphate (DCP) (CaHPO4), used as a nutritional supplement for animal feed. Radioactivity in these samples is due to the presence of the 238U and 232Th radioactive series, as well as their daughter. In addition, as it is for environmental samples, the activity of 40K should be an important source of radioactivity in all analyzed samples. Gamma rays were measured using a standard spectroscopy system, with a high-resolution HPGe detector. Measured activities in feed samples ranged from 0.23 to 1.51 Bq.kg-1, 0.67 to 4.21 Bq.kg-1, 0.29 to 1.63 Bq.kg-1 and 236 to 402 Bq.kg-1 for 226Ra, 228 Ra, 228 Th and 40K, respectively. Measured activities in DCP samples were 46.6 Bq.kg-1, 83 Bq.kg-1, 4.20 Bq.kg-1 and 16.61 Bq.kg-1 for 40 K, 226 Ra, 228 Ra and 228 Th, respectively. Although 40K activity has reached hundreds of Becquerel in feed samples, it should not represent a risk to human health, not even to animals, since potassium is an essential mineral to living organisms.

17.
Mar Pollut Bull ; 97(1-2): 419-430, 2015 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-26036177

RESUMO

This paper reports on the distribution of three natural radionuclides (238)U, (232)Th and (40)K in coastal sediments from Pattipulam to Devanampattinam along the East coast of Tamilnadu to establish baseline data for future environmental monitoring. Sediment samples were collected by a Peterson grab samples from 10m water depth parallel to the shore line. Concentration of natural radionuclides were determined using a NaI(Tl) detector based γ-spectrometry. The mean activity concentration is ⩽2.21, 14.29 and 360.23Bqkg(-1) for (238)U, (232)Th and (40)K, respectively. The average activity of (232)Th, (238)U and (40)K is lower when compared to the world average value. Radiological hazard parameters were estimated based on the activity concentrations of (238)U, (232)Th and (40)K to find out any radiation hazard associated with the sediments. The radiological hazard parameters such as radium equivalent activity (Raeq), absorbed gamma dose rates in air (DR), the annual gonadal dose equivalent (AGDE), annual effective dose equivalent (AEDE), external hazard index (Hex) internal hazard index (Hin), activity utilization index (AUI) and excess lifetime cancer (ELCR) associated with the radionuclides were calculated and compared with internationally approved values and the recommended safety limits. Pearson correlation, principal component analysis (PCA) and hierarchical cluster analysis (HCA) have been applied in order to recognize and classify radiological parameters in sediments collected at 22 sites on East coast of Tamilnadu. The values of radiation hazard parameters were comparable to the world averages and below the recommended values. Therefore, coastal sediments do not to pose any significant radiological health risk to the people living in nearby areas along East coast of Tamilnadu. The data obtained in this study will serve as a baseline data in natural radionuclide concentration in sediments along the coastal East coast of Tamilnadu.


Assuntos
Sedimentos Geológicos/química , Substâncias Perigosas/análise , Radioisótopos de Potássio/análise , Monitoramento de Radiação/métodos , Tório/análise , Urânio/análise , Radiação de Fundo , Análise por Conglomerados , Índia , Análise de Componente Principal , Monitoramento de Radiação/estatística & dados numéricos , Radioisótopos/análise , Espectrometria gama
18.
Chemosphere ; 139: 30-9, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26037957

RESUMO

The Naturally Occurring Radioactive Materials (NORMs) that are potentially generated from oil and gas extractions in Albania have been disposed of without regulations for many decades, and therefore, an extensive survey in one of the most productive regions (Vlora-Elbasan) was performed. A total of 52 gamma ray spectrometry measurements of soil, oil-sand, sludge, produced water and crude oil samples were performed. We discovered that relatively low activity concentrations of (226)Ra, (228)Ra, (228)Th and (40)K, with concentrations of 23±2Bq/kg, 23±2Bq/kg, 24±3Bq/kg and 549±12Bq/kg, respectively, came from the oil-sands produced by the hydrocarbon extraction of the molasses formations. The mineralogical characterizations and the (228)Ra/(40)K and (226)Ra/(40)K ratios of these Neogene deposits confirmed the predictions of the geological and geodynamic models of a dismantling of the Mesozoic source rocks. The average activity concentrations (±standard deviations) of the radium isotopes ((226)Ra and (228)Ra) and of the (228)Th and (40)K radionuclides in soil samples were 20±5Bq/kg, 25±10Bq/kg, 25±9Bq/kg and 326±83Bq/kg, respectively. Based on the measurements in this study, the future radiological assessments of other fields in the region should be strategically planned to focus on the oil-sands from the molasses sediments. Disequilibrium in the (228)Ra decay segment was not observed in the soil, sludge or oil-sand samples within the standard uncertainties. After a detailed radiological characterization of the four primary oil fields, we concluded that the outdoor absorbed dose rate never exceeded the worldwide population weighted average absorbed dose rate in outdoor air from terrestrial gamma radiation.


Assuntos
Campos de Petróleo e Gás , Poluentes Radioativos/análise , Radioisótopos/análise , Albânia , Resíduos Industriais/análise , Petróleo/análise , Monitoramento de Radiação , Solo/química , Espectrometria gama
19.
J Environ Radioact ; 138: 80-6, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25195170

RESUMO

The activity concentrations of (238)U, (232)Th and (40)K in riverbank soil along the Chao Phraya river basin was determined through gamma-ray spectrometry measurements made using a hyper-pure germanium detector in a low background configuration. The ranges of activity concentrations of (238)U, (232)Th and (40)K were found to be 13.9 â†” 76.8, 12.9 â†” 142.9 and 178.4 â†” 810.7 Bq kg(-1), respectively. The anthropogenic radionuclide, (137)Cs, was not observed in statistically significant amounts above the background level in the current study. The absorbed gamma dose rate in air at 1 m above the ground surface, the outdoor annual effective dose equivalent, the values of the radium equivalent activity and the external hazard index associated with all the soil samples in the present work were evaluated. The results indicate that the radiation hazard from primordial radionuclides in all soil samples from the area studied in this current work is not significant.


Assuntos
Poluentes Radioativos do Ar/análise , Radiação de Fundo , Sedimentos Geológicos/análise , Radioisótopos de Potássio/análise , Monitoramento de Radiação , Poluentes Radioativos do Solo/análise , Tório/análise , Urânio/análise , Poluentes Radioativos do Ar/toxicidade , Radiação de Fundo/efeitos adversos , Exposição Ambiental , Humanos , Radioisótopos de Potássio/toxicidade , Doses de Radiação , Rios/química , Poluentes Radioativos do Solo/toxicidade , Espectrometria gama , Tailândia , Tório/toxicidade , Urânio/toxicidade
20.
J Environ Radioact ; 129: 73-9, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24389108

RESUMO

The main goal of this work is to evaluate a correlation between anomalous Uranium (U) content and petrographic features of some soil and rock samples collected at Alte Madonie Mounts region (North-central Sicily, Italy). A total of 41 samples of selected soils and rocks were collected, powdered, dried and sealed in "Marinelli" beakers for 20 days before the measurement to ensure that radioactive equilibrium between (226)Ra and (214)Bi was reached. Gamma-ray spectrometric analysis was used to quantify radioactivity concentrations. Mineralogical and chemical features of the samples were determined by X-ray Fluorescence (XRF), X-ray Diffractometry (XRD), Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) and Scanning Electron Microscope - Energy Dispersive Spectrometry (SEM-EDS) analyses. The average values of concentrations of (226)Ra, (228)Ac and (40)K were respectively 30, 17 and 227 Bq kg(-1) while the greatest values were 134, 59 and 748 Bq kg(-1). Linear relationships were observed between (226)Ra, (228)Ac and (40)K concentrations: the activities of (226)Ra and (228)Ac were comparable, while those of (40)K were about 10 times greater. An exception was highlighted for a group of samples where (226)Ra activities were much higher than expectations. Chemical compositions and mineralogical features of the samples have made it possible to justify these anomalies.


Assuntos
Radioisótopos/análise , Poluentes Radioativos do Solo/análise , Urânio/análise , Bismuto/análise , Fenômenos Geológicos , Itália , Monitoramento de Radiação , Radiometria , Espectrometria gama
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