Preliminary analyses of natural radionuclides in selected Turkish power plant lignites

This preliminary study presents the experimental results concerning the concentrations of selected radionuclides (²³⁸U, ²³²K, ²²⁶Ra, ²³²Th) in Af?in-Elbistan, Çan, Çay?rhan, Erzurum, Göynük, Kangal, Orhaneli, Saray, Seyitömer, Soma, Tunçbilek, Yata?an and Yeniköy lignites, which are primarily utilized as fuel for thermal power plants in Turkey. Gamma-spectrometry of 39 representative lignite samples gave results with the following concentration ranges: 8 to 296 Bq/kg for ²³⁸U, 3 to 79 Bq/kg for ²³²Th, 17 to 360 Bq/kg for 40K, and 5 to 130 Bq/kg for ²²⁶Ra. The ²³⁸U results reported here are higher than other literature values for various world coals, earth's crust and world average.     

Radioactivity levels in soil of three selected sites at and around Riyadh City

In this work the naturally occurring as well as some man-made radionuclidesin soil samples have been experimentally determined to establish the backgroundradioactivity levels in three selected sites at and around Riyadh City. Concentrationsof ²³⁸U and ²³²Th radionuclides together with theirdaughter ²²⁶Ra, ⁴⁰K, ¹³⁷Cs and ¹³⁷Csin soil samples, collected from different locations in the selected siteshave been measured using a hyper-pure high-resolution germanium spectrometer.The obtained concentrations of the studied radionuclides in soil in the selectedsites are presented in tabular form in Bq/kg.     

Application of tracer technique in remediation of Sr(II) from simulated low level radioactive waste

Journal of Radioanalytical and Nuclear Chemistry - Activity concentrations of natural (40K, 226Ra, 228Ra, 232Th, 238U) and artificial (134Cs, 137Cs) radionuclides were measured in powdered milk...     

A new reference material for radionuclides in the mussel sample from the Mediterranean Sea (IAEA-437)

A new Reference Material (RM) for radionuclides in mussel (Mytilus galloprovincialis) from the Mediterranean Sea (IAEA-437) is described and the results of the certification process are presented. Four radionuclides (⁴⁰K, ²³⁴U, ²³⁸U, and ^239+240Pu) have been certified, and information values on massic activities with 95% confidence intervals are given for nine radionuclides (¹³⁷Cs, ²¹⁰Pb(²¹⁰Po), ²²⁶Ra, ²²⁸Ra, ²²⁸Th, ²³⁰Th, ²³²Th, ²³⁵U, and ²⁴¹Am). Results for less frequently reported radionuclides (⁹⁰Sr, ¹²⁹I, ²³⁸Pu, ²³⁹Pu, and ²⁴⁰Pu) are also reported. The RM can be used for quality assurance/quality control of the analysis of radionuclides in mussel samples, for the development and validation of analytical methods and for training purposes. The material is available in 200 g units.     

Analysis of 36Cl in Savannah River Site radioactive waste

The present work shows the activity levels of ²²⁶Ra, ²²⁸Ra, ⁴⁰K and ¹³⁷Cs in bottom sediments collected from eight locations of Mumbai Harbour Bay. The study has shown that ⁴⁰K and ²²⁸Ra concentration is nearly uniform throughout the studied area while ²²⁶Ra and ¹³⁷Cs are more concentrated in the southern regions of the bay. The significant variation in the activity levels of radionuclides within the study site might be due to their sorption/desorption processes onto the surface of sediment materials. The low mean value of ²²⁶Ra/²²⁸Ra ratio (0.72) in the sediments indicates that ²³⁸U has relatively greater solubility and mobility than ²³²Th. Similarly, low activity ratio (0.18) for ¹³⁷Cs/⁴⁰K reflects the presence of very high content of ⁴⁰K in sediment due to presence of primary minerals in sediment. Silt and clay were reported to dominate the composition of the sediment. A significant positive correlation between ²²⁶Ra and ²²⁸Ra and ¹³⁷Cs and ⁴⁰K suggest a similar origin of their geochemical sources and identical behavior during transport in the sediment system.     

Natural radioactivity in soil samples of Kocaeli basin, Turkey

The city of Kocaeli is in the western part of Anatolia in Turkey and has a population of approximately 1.000.000. There is no information about radioactivity in the Kocaeli soils samples so far. For this reason, the concentrations of the natural radionuclides in soil samples from 27 different sampling stations in Kocaeli Basin and its surroundings have been determined. The results have been compared with other radioactivity measurements in different country"s soils. The typical concentrations of ¹³⁷Cs, ²³⁸U, ⁴⁰K, ²²⁶Ra, ²³²Th found in surface soil samples ranged from 2±0.6 to 25±6 Bq/kg, from 11±4 to 49±10 Bq/kg, from 161±30 to 964±127 Bq/kg, from 10±4 to 58±11 Bq/kg, and from 11±3 to 65±13 Bq/kg, respectively.     

Reference material for radionuclides in sediment IAEA-384 (Fangataufa Lagoon sediment)

A reference material designed for the determination of anthropogenic and natural radionuclides in sediment, IAEA-384 (Fangataufa Lagoon sediment), is described and the results of certification are presented. The material has been certified for 8 radionuclides (⁴⁰K, ⁶⁰Co, ¹⁵⁵Eu, ²³⁰Th, ²³⁸U, ²³⁸Pu, ^239+240Pu and ²⁴¹Am). Information values are given for 12 radionuclides (⁹⁰Sr, ¹³⁷Cs, ²¹⁰Pb (²¹⁰Po), ²²⁶Ra, ²²⁸Ra, ²³²Th, ²³⁴U, ²³⁵U, ²³⁹Pu, ²⁴⁰Pu and ²⁴¹Pu). Less reported radionuclides include ²²⁸Th, ²³⁶U, ²³⁹Np and ²⁴²Pu. The reference material may be used for quality management of radioanalytical laboratories engaged in the analysis of radionuclides in the environment, as well as for the development and validation of analytical methods and for training purposes. The material is available from IAEA in 100 g units. Retired from IAEA in 2003.     

Radiological characterization and environmental impact in northwestern coast of Egypt

A study of environmental radioactivity along the northwestern coast of Egypt was performed by the Central Laboratory for Environmental Radioactivity Measurements Inter-comparison and Training within the framework of the research project: Radiological Studies/Measurements of Natural and Man-made Radionuclides in the Environment. The present paper contains important conclusions, correlations and interpretations of the environmental measurements. The samples collection and measurements were conducted according to the Egyptian Atomic Energy Authority monitoring plan for locations along the northwestern coast of Egypt and its main tributaries of interest. The specific activities of ²²⁶Ra (²³⁸U series), ²²⁸Ra (²³²Th series), ⁴⁰K and ¹³⁷Cs (Bq/kg dry weight) were measured using gamma-ray spectrometers based on hyper-pure germanium detectors. The absorbed radiation dose rates in air (nGy/h) due to natural radionuclides in shore sediment and radium equivalent activity index (Bq/kg) were calculated. The specific activity ratios of ²²⁸Ra/²²⁶Ra were calculated for evaluation of the geo-chemical behavior of these radionuclides. Samples textures and CaCO₃ and total organic matter contents of sediments were also determined while the pH, major cations and anions such as Na⁺, K⁺, Ca⁺⁺, Mg⁺⁺and Cl^?, SO₄ ^– and HCO₃, respectively were also determined in water samples.     

Assessment of ingestion dose due to radioactivity in selected food matrices and water near Vizag,India

Activity concentrations of ²³⁸U, ²³²Th, ²²⁶Ra, ⁴⁰K and ¹³⁷Cs were measured in milk, egg, fruit and fish samples collected around a proposed site for setting up nuclear facilities, near Vishakhapatanam. The activity concentrations of the radionuclides ranged from 0.002 to 10.6, 0.002 to 2.8, 0.1 to 7.2, 3 to 110.8, 0.03 to 3 mBq g^?1 for ²³⁸U, ²³²Th, ²²⁶Ra, ⁴⁰K and ¹³⁷Cs considering analysed food matrices. Natural uranium was measured in drinking water samples and the values were below 15 ppb. The average ingestion dose was 2.07 ± 2.01, 2.81 ± 4.38, 7.66 ± 8.24, 1.28 ± 0.84 and 0.04 ± 0.05 μSv year^?1 for ²³⁸U, ²³²Th, ²²⁶Ra, ⁴⁰K and ¹³⁷Cs in milk, egg, fruit, fish and water. The ingestion dose received was the highest for milk, due to its high ingestion rate. It was observed that ²²⁶Ra is the largest contributor of measured radionuclides in this study for the different food matrices analysed due to its high dose conversion factor. The study was carried out as a part of baseline data generation for this region with which future changes in the radiological scenario can be compared.     

Measurement of the radioactivity of238U,232Th,226Ra,137Cs and40K in soil using direct Ge(Li) γ-ray spectrometry

Radioactivity of the nuclides²³⁸U(²³⁵U),²³²Th,²²⁶Ra,¹³⁷Cs and⁴⁰K was measured in soil by direct -ray spectrometry using Ge(Li) detector. Relative laboratory method was used. Soil was dired, powdered, sieved and put into hemetically sealed container. CCRMP certified reference materials and compounds of the above nuclides mixed with fine quartz sand were used as references. Five and four -lines were used for the determination of²³²Th and²²⁶Ra, respectively, to obtain more accurate results. The most significant interferences, caused by the limited energy resolution of the detector, were resolved. In the case of ordinary soils, using one day duration of measurement and 1 kg mass of soil,²³²Th,²²⁶Ra and⁴⁰K can be determined with less than 10% relative random error. Elevated concentrations of²³⁸U(²³⁵U) and²²⁶Ra were observed in soil samples collected around a coal-fired power plant in Ajka town, Hungary.     

The natural radioactivity of Brazilian phosphogypsum

Phosphogypsum is a high volume by-product from the phosphoric acidindustries containing naturally occurring radionuclides. Envisaging the usesof phosphogypsum, a characterization of this material in terms of spatialdistribution of radionuclides was carried out by core samples taken from stacksof two important Brazilian phosphoric acid facilities. Samples were analyzedfor ²³⁸U, ²³⁴U, ²³²Th, ²²⁶Ra, ²²⁸Ra, ²¹⁰Pb and ²¹⁰Po using alpha- and gamma-spectrometryand UV-VIS spectrophotometry. Specific activities of ²³⁸U, ²³⁴U, ²²⁶ Ra and ²¹⁰Po obtained were comparablewith data reported in the phosphogypsum literature, while higher values werefound for ²³² Th and ²²⁸Ra.     

Radioactive series disequilibria in underground uranium deposits of the Singhbhum Shear Zone, Eastern India

Radionuclides of the ²³⁸U series (²²⁶Ra, ²¹⁰Pb, ²³⁴Th and ²³⁴U), ²³⁵U series (²²⁷Ac and ²³¹Pa) and ²³²Th series (²²⁸Th and ²²⁸Ra) series were measured by High Resolution Gamma Spectrometry system in twenty-five uranium ore samples from underground uranium deposits in the Singhbhum Shear Zone of Eastern India. The activity concentrations were observed to vary within a wide range in most of the deposits, as is the case in most rocks of crustal origin. The uranium ore from these deposits were not of high ore grade (U concentrations ranged from 0.015 to 0.082%). Activity ratios of key daughter–parent pairs from the decay chains, viz. ²²⁶Ra/²³⁸U, ²²⁶Ra/²¹⁰Pb, ²³¹Pa/²³⁵U, ²²⁷Ac/²³⁵U, ²³⁰Th/²³⁸U, ²³⁴U/²³⁸U, ²²⁶Ra/²³⁰Th and ²²⁸Th/²²⁸Ra indicated migration/accumulation of uranium and radium in some samples. The ²²⁶Ra/²³⁰Th ARs suggested that the deposits were not closed to groundwater movement for a maximum time period of 8ky. Thiel plot of the ²³⁴U/²³⁸U vs. ²³⁰Th/²³⁸U activity ratios indicated uranium accumulation and complex processes of uranium redistribution.     

Distribution and environmental impact of radionuclides in marine sediments along the Venezuelan coast

The activity concentrations of ¹³⁷Cs, ⁴⁰K, ²²⁶Ra and ²³²Th in Bq/kg from 42 marine sediment samples collected at nine sampling sites were determined in order to establish a radiological baseline along the Venezuelan coast. The radioactivity levels were determined by means of a gamma-ray spectroscopy system using a hyper-pure germanium detector in a low-background configuration. Particle size distribution and total organic matter content were also determined. Activity concentrations of ¹³⁷Cs were lower than the detection limit of the analytical technique (0.9 Bq/kg) in all studied sites. The results suggest that the variation of grain-size distribution is one of the most important factors influencing the spatial variations of ⁴⁰K, ²²⁶Ra and ²³²Th in sediments along the Venezuelan coasts. In all sampling sites, average concentrations of ⁴⁰K, ²²⁶Ra and ²³²Th were lower than the world average values. Activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K in coastal marine sediments along the Venezuelan coast could be considered to be low when compared with global average values, indicating that they are not apparently above of the range that might be considered normal or background. These results suggest that the studied sites do not pose any significant radiological threat to the population. The results attained in this study should be of considerable value as baseline data and background reference levels for Venezuelan coastlines.     

Comparison of analytical methods used to determine <Superscript>235</Superscript>U, <Superscript>238</Superscript>U and <Superscript>210</Superscript>Pb from sediment samples by alpha,beta and gamma spectrometry

An intercomparison of the methodology (alpha, beta and gamma spectrometry) used for ²³⁸U, ²³⁵U and ²¹⁰Pb determination was carried out based on 38 sediment samples. The activity range of the samples varied from 10–700 Bq/kg for ²¹⁰Pb, 1–35 Bq/kg for ²³⁵U and 10–800 Bq/kg for ²³⁸U. Results obtained using the three methods were not statistically different at high activity levels, but agreement between the results decreased at lower sample activity levels. For ²¹⁰Pb, the smallest difference was found between alpha and gamma spectrometry. A good correlation between results from alpha and gamma spectrometry was observed over the whole activity range. In beta spectrometry, the results were slightly higher than those obtained by alpha or gamma spectrometry due to the impurity of ²²⁸Ra. In ²³⁸U analysis, good correspondence was observed between ²³⁸U determined by gamma and alpha spectrometry, particularly at higher ²³⁸U activity concentrations over 100 Bq/kg. In ²³⁵U analysis, attention needs to be paid to interference from ²²⁶Ra and its reduction.     

226Ra, 228Ra and 228Ra/226Ra in surface marine sediment of Malaysia

Surface sediment samples were collected at the West (east coast and west coast of Peninsular Malaysia) and East (Sabah and Sarawak) Malaysia in several expeditions within August 2003 until June 2008 for determining the level of natural radium isotopes. Activity concentrations of ²²⁶Ra and ²²⁸Ra in surface marine sediment at 176 sampling stations were measured. The activity concentrations of both radionuclides in Malaysia (East and West Malaysia) display varied with the range from 9 to 158 Bq/kg dry wt. and 13 to 104 Bq/kg dry wt., respectively. Meanwhile, the ratio distributions of ²²⁸Ra/²²⁶Ra were ranged from 0.62 to 3.75. This indicated that the ratios were slightly high at west coast of Peninsular Malaysia compared to other regions (east coast of Peninsular Malaysia, Sabah and Sarawak). The variation of activity concentrations of ²²⁶Ra and ²²⁸Ra and its ratios were also supported by the statistical analyses of one-way ANOVA and t test at 95 % confidence level, whereby there were proved that the measured values were different between the regions. These different were strictly related to their half-life, potential input sources (included their parents, ²³⁸U and ²³²Th), parent’s characteristic, the geological setting/formation of the study area, environment origin and behavior.     

Measurement of the radioactivity of 238U, 226Ra, 210Pb, 228Th, 232Th, 228Ra, 137Cs and 40K in tea using gamma-spectrometry

The aim of the present work was to determine the concentration of radionuclides in all kinds of tea available at the local Egyptian market. Radioactivity of the nuclides ²³⁸U, ²²⁶Ra, ²¹⁰Pb, ²²⁸Th, ²³²Th, ²²⁶Ra, ¹³⁷Cs and ⁴⁰K were measured in tea by direct γ-ray spectrometry using HPGe detector and their mean values were 16.0±5.3, 3.1±0.7, 34.3±3.4, 3.4±1.2, 3.0±0.6, 3.1±0.8, 0.9±0.2 and 623±25 Bq·kg⁻¹, respectively.     

Study of naturally occurring radioactive material (NORM) in top soil of Punjab State from the North Western part of India

The concentration levels of ²³⁸U, ²³² Th, ⁴⁰K and ¹³⁷Cs in top soils of State of Punjab located in the North Western part of India were measured using conventional low background gamma ray spectrometric setup as well as Compton suppressed gamma ray spectrometric setup. The radioactivity level of ²³⁸U and ²³²Th was found to vary between 15 Bq/kg and 27 Bq/kg and between 16 Bq/kg and 57 Bq/kg respectively. The radioactivity level of ⁴⁰K was found to vary between 266 Bq/kg and 799 Bq/kg. The mean radioactivity level of the NORM in general was found to be similar to what is expected as a result of their normal abundance.     

Radionuclide activities and elemental concentrations in sediments from a polluted marine environment (Saronikos Gulf-Greece)

The levels and depth distributions of the natural radionuclides ²³⁸U, ²³²Th, ²²⁶Ra, ⁴⁰K and the man-made ¹³⁷Cs were analyzed by γ-ray spectrometry, while the concentrations of 26 chemical elements were measured by INAA in sediment samples collected from the organic mud layer that covers the Keratsini–Psitalia strait, Saronikos gulf (Greece). The average activity concentration values of ²²⁶Ra, ²³²Th and ⁴⁰K were lower when compared, whereas that of ²³⁸U was comparable to the average Greek and world values. The elemental contamination of the sediments was estimated on the basis of the calculated EF values. The results revealed high EF values of As, Br, Cr, Ni, Sb, Se, Zn ranging from 160 for Br to 10 for Cr, whose main sources are probable related to contaminated sewage outfall from the area of Athens and the Piraeus Harbour.

     

Assessment of radioactivity level and associated radiation exposure in topsoil from eastern region of Shangrao Prefecture,China

Natural and fallout radioactivity were estimated in topsoil samples collected in eastern region of Shangrao Prefecture, China. The average activity concentrations of ²³⁸U, ²²⁶Ra, ²³²Th and ⁴⁰K in the soil were nearly 2 times the world median value and Chinese average. The ¹³⁷Cs activity concentration decreased compared with the previously reported value in the same region. The absorbed dose rate and annual effective dose rate estimated in the study area are found to be both higher than the world average values. ²³⁸U/²²⁶Ra and ²³²Th/²²⁶Ra activity ratios were also considered in this study.

     

Terrestrial absorbed dose rate measurement in the Jhangar valley of Pakistan

Specific activity of natural radionuclides; ²²⁶Ra, ²³²Th and ⁴⁰K were measured in the agricultural soil of eastern salt range of Pakistan using gamma ray spectrometry. The soil samples were collected within the ploughing region (up to 12 cm depth) and processed before analysis. The average specific activities of different radionuclides in the dry mass of soil samples were: ⁴⁰K, (666 Bq/kg), ²²⁶Ra (51 Bq/kg), and ²³²Th (59 Bq/kg). The average outdoor terrestrial absorbed dose rate in air from gamma radiation one meter above ground surface was found to be 93 nGy/h.