Mineralogical, geochemical and radiological characterisation of Selmo Formation in Batman area, Turkey

This work deals with the mineralogical, geochemical and radiological characterisations of Selmo Formation in Batman neighbourhood. The upper Miocene-Pliocene Selmo Formation is common in the centre of Batman and composed of carbonated sandy claystones and silty-sandy stone lenses. The common whole minerals of the samples are quartz, feldspars, calcite and dolomite. The clay minerals are smectite, illite, chlorite and mixed-layer clay (chlorite-smectite). The geochemical mean values of the samples are 51.7% SiO(2); 12.6% Al(2)O(3); 6.2% Fe(2)O(3); 3.6% MgO; 6.3% CaO; 1.1% Na(2)O; 1.7% K(2)O; 0.8% TiO(2); 0.2% P(2)O(5); 0.1% MnO; and 0.03% Cr(2)O(3). In addition, baseline maps for the concentrations of each radionuclide, the radium equivalent activity and the outdoor gamma dose rate distributions have been plotted for the study area. The mean activity concentrations of (226)Ra, (232)Th, (40)K and (137)Cs were determined to be 32, 24, 210 and 9?Bq?kg(-1), respectively. The assessments of the radiological hazard indices, such as radium equivalent activity, absorbed dose rate in air, annual effective dose equivalent, excess lifetime cancer risk, external hazard index and internal hazard index, were calculated and compared with the internationally accepted reference values. This study shows that the concentrations of radioactivities in the measured samples were within the recommended safety limits and did not pose to be any significant source of radiation hazard.     

Assessment of natural radionuclides and their radiological hazards in commercial granite produced in Xinjiang,China

ABSTRACT

The specific activities of ²²⁶Ra, ²³²Th and ⁴⁰K of 26 samples of granite produced in Xinjiang of China were measured by a high-purity germanium detector, and their radiological hazards of radium equivalent, external hazard index, internal hazard index, absorbed dose rate, annual effective dose rate, gamma index and alpha index were evaluated. The results indicate that the overall average specific activities of ²²⁶Ra, ²³²Th and ⁴⁰K obtained in the investigated samples are below the world’s average granite values. The average radium equivalent is within the recommended limit of 370?Bq?kg^?1. The results obtained further show that the mean values of external hazard index, internal hazard index, absorbed dose rate, annual effective dose rate, gamma index and alpha index are 0.65, 0.77, 111.7?nGy?h^?1, 0.55 mSv?y^?1, 0.89 and 0.23, respectively. These mean values established that radiological hazards are also found to be below the international recommended values. The results are compared with granite samples from other countries or China-Taiwan province. It can be noticed that the specific activity values of granite samples produced in China are lower or similar to that of other countries or China-Taiwan province, however there are higher specific activity values for ²²⁶Ra and ²³²Th in individual samples, which need to provide proper radiation monitoring before use considering the long term health effect.     

Natural radionuclide concentrations in soils around Baoji coal-fired power plant,China

Radionuclides are released together with fly ash from the coal-fired power plant and thus add to the natural radiation. Fifty soil samples were collected around the Baoji coal-fired power plant from 25 locations and the natural radionuclide concentrations were determined by a gamma ray spectrometric system. The results show that the activity concentrations in soil samples range from 12.54 to 40.18 Bq kg^?1, 38.02 to 72.55 Bq kg^?1 and 498.02 to 1126.98 Bq kg^?1 for ²²⁶Ra, ²³²Th and ⁴⁰K with the mean values of 27.35, 52.66 and 764.72 Bq kg^?1, respectively. In order to evaluate the radiological hazard of the natural radioactivity, the radium equivalent activity (Ra_eq), the absorbed dose rate (D) and the annual effective dose rate have been calculated and compared with the internationally approved values. The radium equivalent activity in all the soil samples is lower than the safe limit set in the Organization for Economic Cooperation and Development report (370 Bq kg^?1). The average value of the calculated dose rates is higher than the global average value 55 nGy h^?1, and the calculated annual effective dose rate is significantly lower than the average annual external effective dose rate (460 μSv y^?1) of the normal background radiation.     

Radiometric analysis and radiological hazards of Chinese commercial marble

The activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K in commercial marble materials have been determined using a NaI(Tl) γ-ray spectrometer with a matrix-inversion-based spectral stripping technique. Knowledge of radioactivity present in marble materials enables one to assess any possible radiological risks to human health. The concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K in Chinese commercial marble range from 8.4 to 157.4, 5.6 to 165.5 and 44.1 to 1352.7 Bq kg^?1, respectively. The natural radionuclide concentration varied with color and production site of commercial marble. The activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K in white, gray, black, green and yellow marble samples are comparatively smaller than those in brown and red marble samples. The radium equivalent activity (Ra_eq), the external hazard index (H _ex), the internal hazard index (H _in) and the annual gonadal dose equivalent were also calculated and compared with the internationally recommended values. One type of brown commercial marble (TSB) of China does not satisfy the universal standards.     

Radon survey and soil gamma doses in primary schools of Batman,Turkey

A survey was conducted to evaluate levels of indoor radon and gamma doses in 42 primary schools located in Batman, southeastern Anatolia, Turkey. Indoor radon measurements were carried out using CR-39 solid-state nuclear track detector-based radon dosimeters. The overall mean annual ²²²Rn activity in the surveyed area was found to be 49 Bq m^?3 (equivalent to an annual effective dose of 0.25 mSv). However, in one of the districts (Besiri) the maximum radon value turned out to be 307 Bq m^?3. The estimated annual effective doses are less than the recommended action level (3–10 mSv). It is found that the radon concentration decreases with increasing floor number. The concentrations of natural and artificial radioisotopes were determined using gamma-ray spectroscopy for soil samples collected in close vicinity of the studied schools. The mean gamma activity concentrations in the soil samples were 31, 25, 329 and 12 Bq kg^?1 for ²²⁶Ra, ²³²Th, ⁴⁰K and ¹³⁷Cs, respectively. The radiological parameters such as the absorbed dose rate in air and the annual effective dose equivalent were calculated. These radiological parameters were evaluated and compared with the internationally recommended values.     

Determination of 226Ra, 232Th and 40K in teeth by use of gamma spectroscopy

This study entails the measurement of the specific activity of natural radionuclides (²²⁶Ra, ⁴⁰K and ²³²Th) in 18 tooth samples obtained from the clinic of the Universiti Sains Malaysia (USM), Penang, by using an HPGe detector. The specific activity of ²²⁶Ra, ⁴⁰K and ²³²Th was measured to estimate the hazard index of the radionuclides, radium equivalent activities (Ra_eq), external, internal hazard indices (H_ex, H_in), and absorbed dose (D_out, D_in). The maximum values of concentration of ²²⁶Ra, ²³²Th and ⁴⁰K in the tooth samples were found to be 60.82, 60.29 and 594.22?Bq kg^?1, respectively. Maximum values of Ra_eq, H_ex, H_in, D_out and D_in were found to be 192.78?Bq kg^?1, 0.520, 0.685, 89.29 and 169.81?nGy h^–1, Iγ and Iα as 0.702 and 0.304, respectively. The results were lower than the average world value (UNSCEAR). In addition, a strong correlation was found between the concentrations of ²²⁶Ra and Ra_eq, between energy and net area, as well as between radionuclides (²²⁶Ra, ⁴⁰K and ²³²Th) in tooth samples and age of volunteers. This study showed that the concentrations and hazard indices of tooth samples are below the recommended safe levels; therefore, the study area is considered safe in terms of radiological health hazards.     

Structure,phase composition,and spectral luminescence properties of partially stabilized zirconium dioxide crystals doped with Yb<Superscript>3+</Superscript> ions

Investigation of partially stabilized zirconium dioxide crystals via transmission electron microscopy has revealed a developed twin structure therein. The following compositions of the above crystals have been selected for this study: 97.2 mol % ZrO₂–1.0 mol % Y₂O₃–1.8 mol % Yb₂O₃; 97.2 mol % ZrO₂–2.0 mol % Y₂O₃–0.8 mol % Yb₂O₃; 97.2 mol % ZrO₂–2.5 mol % Y₂O₃–0.3 mol % Yb₂O₃; and 96.3 mol % ZrO₂–3.4 mol % Y₂O₃–0.3 mol % Yb₂O₃. X-ray diffraction analysis of these crystals indicate the presence of transformable (t) and nontransformable (t') tetragonal phases. Optical spectroscopy measurements of ZrO₂–Y₂O₃–Yb₂O₃ crystals with tetragonal and cubic structures have highlighted in Yb³⁺-doped zirconium dioxide samples the formation of the optical centers of the Yb³⁺ ions is observed, whose crystal surrounding is similar to those in cubic zirconium dioxide crystals.     

The determination of concentrations of radioisotopes in some granite samples in Turkey and their radiation hazards

The primordial radionuclides activity concentrations (²²⁶Ra, ⁴⁰K and ²³²Th) are measured in some granite samples in this study. The collected granite materials are analyzed with NaI(Tl) gamma-ray spectrometry. The specific activity of ²²⁶Ra, ²³²Th and ⁴⁰K values are in range 2.60?±?0.10 to 178.9?±?0.6?Bq?kg^?1, 1.46?±?0.10 to 162.50?±?0.75?Bq?kg^?1 and 19.8?±?0.3 to 579.7?±?2.8?Bq?kg^?1 respectively. The radium’s equivalent activity, annual effective dose, absorbed dose rate, hazard index, radioactivity level index, activity utilization’s index and exposure rate are calculated for determination of radiological risk. The concentration of ²²⁶Ra (in the 71.4% of samples), ²³²Th (in the 71.4% of samples) and ⁴⁰K (in the 14.3% of samples) in the granite samples are higher than average radioactivity concentrations of this radio-isotopes defined by ICRP (35.0, 30.0 and 400.0?Bq?kg^?1, respectively).     

Mössbauer and X-ray study of the firing process for production of improved roofing tiles

The effects of firing atmosphere parameters on the microstructural characteristics and physical properties of clay roofing tiles were studied. For these investigations, ⁵⁷Fe Mössbauer spectroscopy, X-ray diffractometry and dilatometry were used. XRD of the raw material exploited from the clay pit belonging to the roofing tile factory “Potisje-Kanjiza”, revealed the presence of montmorillonite, kaolinite, illite and some chlorite clay minerals, as well as, quartz, albite, calcite and dolomite. Gradual changes were observed both in the ⁵⁷Fe Mössbauer spectra and X-ray diffractograms with samples fired in reducing CO/N₂ gas atmosphere at temperatures between 700 and 1060 °C. These changes reflect the dehydroxylation processes, oxide (Fe₃O₄) formation, carbonate decomposition, densification and new silicate (plagioclase) formation. The firing conditions in reducing atmosphere were determined to produce roofing tiles with improved properties.     

Natural radioactivity and radiation hazards assessment of soil samples from the area of Tuzla and Lukavac,Bosnia and Herzegovina

The results of activity concentration measurements of natural occurring radioactive nuclides ²³⁸U, ²³⁵U, ²³²Th, ²²⁶Ra, and ⁴⁰K in surface soil samples collected in the area of cities Tuzla and Lukavac, northeast region of Bosnia and Herzegovina were presented. Soil sampling was conducted at the localities that are situated in the vicinity of industrial zones of these cities. The measured activity was in the range from (8?±?4) to (95?±?28) Bq kg^–1 for ²³⁸U, from (0.41?±?0.06) to (4.6?±?0.7) Bq kg^–1 for ²³⁵U, from (7?±?1) to (66?±?7) Bq kg^–1 for ²³²Th, from (6?±?1) to (55?±?6) Bq kg^–1 for ²²⁶Ra, and from (83?±?12) to (546?±?55) Bq kg^–1 for ⁴⁰K. In order to evaluate the radiological hazard of the natural radioactivity for people living near industrial zones, the absorbed dose rate, the annual effective dose and the radium equivalent activity have been calculated and compared with the internationally approved values.     

Environmental radioactivity of soils and sediments: Egyptian sector of the Nile valley

The activity concentrations of natural ⁴⁰K, ²³²Th, and ²³⁸U in 89 soil and 84 sediment samples collected over the entire Egyptian Nile River basin including the Nile delta are reported based on the results of epithermal neutron activation analysis. The average activity concentrations of ⁴⁰K, ²³²Th, and ²³⁸U equal to 15.3?±?6.6, 15.6?±?11.1 and 220?±?31 Bq/kg, respectively, are significantly lower than those reported for the Upper Continental Crust, World Average Sediments as well as World Average Soils, suggesting the presence of a considerable portion of mafic material, most probably originating from the Ethiopian High Plateau. Their average activity concentrations are statistically the same in soil and sediments, indicating that the Nile sediments and soil material are of the same origin. The main goal of this study was not only to estimate the radiological hazards but also to show the influence of sedimentary material transportable by the Blue Nile from the Ethiopian High Plateau. The different hazard indices like the radium equivalent, gamma index, external hazard as well as the internal hazard show a low radiological exposure either on direct contact or if local mud bricks are used in the construction of dwellings.     

Evaluation of radiation level and radon exhalation rate of rock samples from Mahd Ad Dahab mine in Saudi Arabia

Mahd Ad Dahab mine is the largest and oldest gold mine in the middle East, situated in the western region of Al-Madina Al-Munawara in Saudi Arabia. By using a high-resolution gamma-ray spectroscopy system, various radionuclides in about 20 rock samples, collected from four different locations of the Mahd Ad Dahab mine, have been identified quantitatively based on their characteristic spectral peaks. The activity concentrations of the natural radionuclides uranium (²³⁸U), thorium (²³²Th), and potassium (⁴⁰K) as well as some radiological parameters were measured in the rock samples. The activity concentration of uranium was found to vary from 7.94 to 38.52 Bq/kg, thorium from 3.14 to 17.79 Bq/kg and potassium activity from 93.51 to 175.83 Bq/kg. The radon emanation coefficient of the rock samples was estimated. It ranged between 0.48 and 0.55. Moreover, the radium equivalent activity in the samples ranged between 19.3 and 77.49 Bq/kg, which is lower than the allowed maximum value for worker safety. The external and internal hazard indices and gamma-radiation hazard index were found not to exceed the permissible limits.     

Radon exhalation rate in Chhatrapur beach sand samples of high background radiation area and estimation of its radiological implications

Chhatrapur beach placer deposit, situated in a part of the eastern coast of Orissa, is a newly discovered high natural background radiation area (HBRA) in India. The sand samples containing heavy minerals, were collected from Chhatrapur region by the grab sampling method at an interval of ∼1 Km. Radon exhalation rates were measured by “Sealed Can Technique” using LR-115 type type II in the sand samples containing heavy minerals collected from the beach. Radon activity is found to vary from 1177.1 to 4551.4 Bq m-3 whereas the radon exhalation rate varies from 423.2 to 1636.3 mBq m⁻²h⁻¹ with an average value of 763.9 mBq m⁻²h⁻¹. Effective dose equivalent in sand samples estimated from exhalation rate varies from 49.9 to 193.0 μSv y⁻¹ with an average value of 90.1 μSv y⁻¹. From the activity concentration of ²³⁸U, ²³²Th and ⁴⁰K computed radium equivalent is found to vary from 864.0 to 11471.5 Bq kg⁻¹ with an average value of 3729.0 Bq kg⁻¹. External hazard index, H_ex range from 2.3 to 31.0 with a mean value of 10.1, which is quite high. This value supports the conclusion based on high mean absorbed gamma dose rate in air due to the naturally occurring radionuclides as 1627.5 nGy h⁻¹. A positive correlation has been found between U concentration and radon exhalation rate in the sand samples. The use of sand as construction material may pose a radiation risk to ambient environment.      

Li+ ion conducting γ solid solutions in the systems Li4XO4-Li3YO4: X=Si,Ge, Ti; Y=P,As, V; Li4XO4-LiZO2: Z=Al,Ga, Cr and Li4GeO4-Li2CaGeO4

A wide variety of solid solutions with a structure related to that of γ Li₃PO₄ may be prepared. These include materials such as lisicon, Li_2+2xZn_1-xGeO₄ and the title systems, many of which have not been studied previously. Conductivity data are presented for eight systems: Li₄GeO₄-Li₃(P, As, V)O₄; Li₄TiO₄-Li₃(As, V)O₄; Li₄GeO₄-Li(Ga, Al)O₂; Li₄GeO₄-Li₂CaGeO₄ and the results compared with those reported in the literature for Li₄SiO₄-Li₃(P, As, V)O₄ systems and lisicon. dc polarisation measurements were made on four of the system and it was found that the electronic transference number is 10^?4 or less. The materials with the highest conductivity were found in the systems, Li₄ (Ge, Ti) O₄-Li₃ (As, V)O₄ with σ ~ (3 to 4) × 10^?5 Ω^?1 cm^?1 at room temperature. It is noted that the systems with the highest conductivity are generally those with the largest unit cell volume.     

Clay fraction mineralogy of a Cambisol in Brazil

Clay minerals having a 2:1 (tetrahedral:octahedral sheet) structure may be found in strongly weathering soils only if the local pedo-climatic environment prevents them from further weathering to other minerals such as iron oxides. The clay minerals impart important chemical properties to soils, in part by virtue of changes in the redox state of iron in their crystal structures. Knowing the chemical nature of soil clays is a first step in evaluating their potential reactivity with other soil constituents and processes, such as the chemical decomposition of organic substrates to be potentially used in environmental remediation. The purpose of this work was to characterize the iron oxides and iron-bearing clay minerals from a B horizon of a Cambisol developed on tuffite in the State of Minas Gerais, Brazil, using chemical analysis, powder X-ray diffraction, Mössbauer spectroscopy, and thermal analysis. The iron oxides of this NaOH-treated clay-fraction were found to contain mainly maghemite (γFe₂O₃) and superparamagnetic goethite (αFeOOH). Kaolinite (Al₂Si₂O₅(OH)₄), smectite, and minor portions of anatase (TiO₂) were identified in the CBD-treated sample.     

Unexpected radiation hazard in dyes of textiles

Textile dyes are among the most problematic pollutants because of their toxicity on several organisms and ecosystems. Many of the chemicals used in the textile industry may represent some health concerns. The determination of the radioactivity in textile dyes is therefore very important for both human health and environment. The study was designated to determine, for the first time, the values of ²³⁸U, ²³²Th and ⁴⁰K in nine different dyes employed in the textile industry using gamma spectrometry with a Hyper Pure Germanium (HPGe) detector. The mean activity concentrations of ²³⁸U, ²³²Th and ⁴⁰K were 29.37?±?4.48, 1.15?±?0.13 and 565?±?4 Bq/kg, respectively. The calculated radium equivalents for all samples were lower than the maximum admissible value (370 Bq/kg). The absorbed dose rates due to the natural radioactivity of the investigated samples ranged from 2.94?±?0.05 to 166?±?3 nGy/h. So, the absorbed dose rates for all samples of textile dyes were lower than the international recommended value (55 nGy/h) except the yellow dye (166?±?3 nGy/h), which recorded a significant radiological hazard. The external hazard index was also calculated. Conclusively, the results have indicated that the textile dyes may possess a measurable amount of radioactivity that should be taken into account. Therefore, safety rules and precautions should be applied for dyes used in the textile industry and for people working in this field.     

Mössbauer study of amorphous BaO−Fe2O3−B2O3 system

HomogeneousBaO?Fe₂O₃?B₂O₃ glasses containing maximum Fe₂O₃ content of 63 mol.% are prepared by splat cooling technique. Mössbauer study reveals that the glass mainly consists of tetrahedral network of Fe³⁺O₄. Mössbauer spectrum of the glass shows a well defined hyperfine structure at low temperatures. Magnetic ordering temperature estimated is about 130 K for the most iron-rich specimen, being much lower than that of the corresponding crystalline phases, BaO;·;Fe₂O₃ and BaO·;2Fe₂O₃. The magnetic structure is suggested to be of a short-range antiferromagnetic ordering.     

Measurement of radionuclides and absorbed dose rates in soil samples of Peshawar,Pakistan, using gamma ray spectrometry

The analysis of gamma-emitting radionuclides in nature, i.e. ²²⁶Ra, ²³²Th, ⁴⁰K and ¹³⁷Cs, has been carried out in soil samples collected from Peshawar University Campus and surrounding areas using a high purity germanium detector coupled with a computer-based high-resolution multichannel analyser. The activity concentrations in soil ranged from 30.20±0.65 to 61.90±0.95, 50.10±0.54 to 102.80±1.04, 373.60±4.56 to 1082±11.38 and 9.50±0.11 to 46.60±0.42 Bq kg^?1 for ²²⁶Ra, ²³²Th, ⁴⁰K and ¹³⁷Cs, with a mean value of 45±7.70, 67±12.50, 878±180 and 19±9.20 Bq kg^?1, respectively. The radium equivalent activity, internal and external hazard indices have mean values of 203.40±29.40 Bq kg^?1, 0.56 and 0.68, respectively. The mean values of outdoor and indoor absorbed dose rates in air and the annual effective dose equivalents were found to be 106.50 and 128 nGy h^?1 and 0.19 and 0.54 mSv y^?1, respectively. In the present study, ⁴⁰K was the major radionuclide present in soil samples. The presence of ¹³⁷Cs indicates that this area also received some fallout from the nuclear accident of the Chernobyl power plant in 1986. The activity concentrations of radionuclides found in soil samples during the current investigation were nominal. Therefore, they are not associated with any potential source of health hazard to the public.     

Natural radionuclides and hazards of rock samples collected from Southeastern Nigeria

Gamma radiation from natural radionuclides in thirty eight rock samples collected from Southeastern Nigeria was measured using gamma-ray spectrometry method. The activity concentrations varied from 13.1 ± 1.6 Bq kg⁻¹ (ferrogeneisis shale) to 129 ± 38 Bq kg⁻¹ (granite) for ²²⁶Ra, 42.4 ± 4.5 Bq kg⁻¹ (siltstone) to 150 ± 23 Bq kg⁻¹ (pegmatite) for ²³²Th and 64.5 ± 6.3 Bq kg⁻¹ (ferrogeneisis shale) to 882 ± 298 Bq kg⁻¹ (granite) for ⁴⁰K. Hazard indices were used to determine the suitability of the rock samples for building in the context of radiological hazard. The results obtained for the radium equivalent activity and the external hazard index show that two of the samples, granite and pegmatite exceeded the recommended limits of 370 Bq kg⁻¹ and 1, respectively. However the results of the gamma index were below the recommended limit. The dose rates and the annual effective dose calculated ranged from 0.012 to 0.042 μGy h⁻¹ and 0.06–0.21 mSv, respectively.