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Determination of elemental concentrations of radionuclides in Turkish bentonite and calculation of radiogenic heat generation
Abstract
Bentonite containing smectite group clay minerals is an industrial raw material with a wide range of uses. In this study, the concentration of uranium, thorium, and radioactive potassium in ninety bentonite samples collected from quarries in Turkey was determined using an energy-dispersive X-ray fluorescence spectrometer. The concentrations of uranium, thorium and potassium varied from 0.4 to 18.2 with an average of 4.3 mg/kg, 5.4 to 53.4 with an average of 22.7 mg/kg and 0.3 to 3.4 with an average of 1.4 mg/kg, respectively. The radiogenic heat generation caused by the ionising radiation emitted from these radioactive elements in bentonite samples was calculated in the range of 0.9 to 6.6 µW/m³ with an average of 2.8 µW/m³.
... However, due to strong cation adsorbing capacity bentonite usually contains uranium, thorium and potassium in varying concentrations (Turhan et al. 2022). On the other hand, uranium and thorium containing materials are consequently sources of radon and exhalate their gaseous radionuclide since Rn-222 and Rn-220 are members of the U-238 and Th-232 decay series, respectively. ...
The main component of clumping cat litter is usually bentonite, which besides potassium (including K-40) contains uranium radium, and may also exhalate radon. Ten different cat litter samples, which are commercially available in Cyprus and have been imported from various countries, have been analysed regarding their uranium and radium levels, and the associated radon exhalation rates. The uranium levels varied between 2.5 mg/kg (32 Bq/kg) and 4 mg/kg (50 Bq/kg) and were determined by ICP-OES after acidic dissolution of the cat litter samples. The radioactivity concentration of radium in the samples (4 Bq/kg < [Ra-226] < 40 Bq/kg) was determined after EDTA extraction of radium from the litter matrix followed by the determination of the associated radon exhalation rates using a continuous radon monitor. Similarly, the radon exhalation from cat litter was measured using a defined amount of cat litter and the average radon levels emitted varied between (6 Bq m-3 < [Rn] < 128 Bq m-3). However, even in the case of the cat litter with the highest radionuclide concentration, the contribution to indoor radon in an average room is estimated to be insignificant and subsequently the impact of the associated additional radioactive dose.
The Pb, Cr, Cd, Ni, Zn, Cu, Co, As, Sr, Ba, and Zr content has been determined in the tested rock raw materials. The concentration of cadmium (Cd) was found to be elevated in all types of rock materials and was found on average to be: 1.39 mg/kg in limestones, 0.86 mg/kg—sandstones, 0.44 mg/kg—diatomites, 0.55 mg/kg—opoka rocks, 0.89 mg/kg—marls, 0.21 mg/kg—gaizes 0.42 mg/kg—kaolin clays, and 2.13 mg/kg—decalcified opoka rocks. Higher concentrations of arsenic (As) have also been recorded in sandstones and diatomites, as well as lead (Pb) in limestones and sandstones. The results obtained indicate that the anomalous level of elements is of natural origin and the results of identified secondary mineralisation processes that have affected the tested materials. Pyritization and sulfatization processes have been detected. Mineralogical research has shown that these processes can be associated with the activity of biochemical processes caused by the decomposition of the soft tissues of animal organisms and the organic substances of plant origin that fill the stylolites. It has been shown that the content of strontium (Sr) increases in geologically older Jurassic formations compared to younger Cretaceous formations, which can be used in the monitoring of building materials.
The study highlights a rising number of fluids such as nanofluids that encountered in daily life exhibit non-Newtonian behavior and it is exploited in manufacture due to their high heat transfer rate becoming more and more important as time goes on. Brownian motion provided by the bombardment of fluid particles from the surrounding medium. In this article, we address the influence of the Brownian motion with thermophoresis on the flow of Casson- magnetohydrodynamics nanofluid. flow over a non-linear stretching surface have analysed. Impact of the viscous dissipation, heat absorption and suction introduce in the system. Using proper similarity conversion, the controlling PDEs turned into ODEs. The conversion governing equations of first-order ODEs are solved numerically by utilizing an explicit finite difference technique. The similarity equations elucidated in the view of shooting technique and used with software package bvp4c MATLAB. The flow velocity, temperature and concentration followed up with the nonlinearity nature and the influence results are displayed in graphical form. The outcomes of skin frictions, Nusselt and Sherwood numbers are summarized for various leading parameters are in the form of table. Activation energy enhanced the mass transfer rate. However, a reverse phenomenon detected with the higher value of chemical reaction parameter. According to the results of the simulation, the skin friction decreased with the Casson and permeability parameters, while the heat transmission remain constant with the increased values of the constants.
The relationship between infections and renal calculi has been known since the time of Hippocrates, but it was not until 1817 that Marcet identified the connection between urinary alkalinity, infection, phosphate calculi, and increased urinary ammonia. In 1901, Brown first suggested that urea splitting bacteria activity increased urinary ammonia production, which was the immediate cause of higher urinary alkalinity levels and phosphate (struvite) stone formation. The 1926 description of urease, the first enzyme ever isolated and purified, earned Sumner the Nobel Prize for Chemistry in 1946. Struvite is a crystalline compound made up of magnesium ammonium phosphate (MgNH4PO4.6H20). Struvite stones are actually a mixture composed of three cations (calcium, magnesium, ammonium) and one anion (phosphate). They are therefore also known as triple phosphate stones even though pure struvite actually contains no calcium. The mixture is composed of struvite (MgNH4PO4.6H20) and calcium phosphate (Ca10.[PO4]6.CO3); hence carbonate ions are also usually found. They can form in the kidney or bladder in patients with catheters or urinary stasis. For example, about 8% of patients with spinal cord lesions will form stones, and 98% of these will be struvite. If left untreated, renal struvite stones have a tendency to grow more rapidly compared to calcium-based stones and may eventually fill up the entire collecting system. This can lead to a staghorn stone or branched calculus formation. Among all stone formers, the percentage of struvite stones was found to be 5% to 15%. Struvite stones only form in alkaline environments (pH >7) and are always associated with urinary tract infections from urease-producing bacteria such as Proteus. Virtually all infectious urinary organisms make urease except E. coli, Citrobacter freundii, Streptococci, and Enterococci. It should be pointed out that staghorn stones, while predominantly made of struvite or triple phosphate, may also be composed of mixtures of calcium oxalate, calcium phosphate, uric acid, and cystine. However, for the purpose of this review, we shall focus exclusively on struvite staghorn calculi.
Fig.1 Struvite (magnesium ammonium phosphate / triple phosphate) crystals in a human urine sample, detected by microscope
The figure shows a microscopic photograph of a struvite crystal in a 56-year-old patient who does not have kidney disease but has frequent recurrent urinary infections.
Key words: urine, infection, struvite crystals
Potentially toxic elements (PTEs) are an important type of pollutant, causing constant and far-reaching concerns around the world due to their increase in the mining process. Bentonite formed by the alteration of glass-rich volcanic rocks is a smectite clay consisting mostly of montmorillonite. Bentonite is an important mineral used in a wide range of applications in many fields such as oil and gas, agriculture, food, pharmacological, cosmetic, and construction industries due to its unique qualities. Given the widespread distribution of bentonite in nature and its use in a wide variety of consumer products, it is inevitable that the general population will be exposed to PTEs contained in bentonites. In this study, concentrations of PTEs in 69 bentonite samples collected from quarries located in different geographical regions of Turkey were analyzed by an energy-dispersive X-ray fluorescence spectrometric method. The average concentrations of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Zr, and Pb in bentonite samples were found to be 3510, 95, 129, 741, 30,569, 67, 168, 25, 62, 9, 173, and 28 mg/kg dry weight, respectively. Results of the enrichment factor relating to Earth's crust average indicated moderate enrichment with Cr, Ni, and Pb and significant enrichment with Co and As.
Bu çalışmada, depremlerde malzeme seçimi kaynaklı hasarların yapıların deprem yükleri altındaki
davranışlarının simülasyonları yaparak incelenmesini ele almaktadır. Deprem, dünyada birçok ülkeyi etkileyen
ciddi bir sorun olup, en önemli doğal afetlerden biridir. Son 6 Şubat 2023 tarihinde 7,7 Mw Kahramanmaraş
depreminde de birçok binanın yıkılmasına sebep olmuştur. Bu yıkımların da geneli malzeme seçiminden
kaynaklı yıkıldığı belirlenmiştir. Bu amaçla, bu çalışmada Kahramanmaraş depremi gibi gerçek bir depremin
verileri kullanılarak bir yapı modeli oluşturulmuştur. Yapı modeli, malzeme özellikleri, boyutları ve geometrisi
dikkate alınarak hazırlanmıştır. Bu yapı modeli, deprem yükleri altında nasıl davrandığını görmek için simüle
edilmiştir. Simülasyon sonucunda, malzeme seçiminin yapısal performans üzerindeki etkisi incelenmiştir.
Ayrıca, yapıda oluşan hasarın nedenleri de tespit edilmiştir. Bu çalışma, malzeme seçiminin yapıların deprem
performansına olan etkisini açıkça göstermektedir. Çalışmada ayrıca, malzemenin deprem performansını
artırmaya yönelik yapılmış araştırmalardan incelenmiştir. Özellikle, daha farklı malzeme türleri ve yapı tipleri
üzerinde incelenmeler yapılmıştır. Ayrıca, daha geniş kapsamlı araştırmaların yapılması ve farklı deprem
senaryolarının simülasyonunun gerçekleştirilmesi önerilmiştir. Çalışmanın sonucunda, Kahramanmaraş
depreminde yıkılan birçok binanın mukavemeti düşük beton ve düz demir kullanımından dolayı çöktüğü
görülmüştür. Yapılarda malzeme seçiminin deprem performansına olan etkisini incelenerek elde edilen
sonuçların yapılan deneylerle karşılaştırılarak veriler bulunmuştur. Elde edilen özellikle yapı tasarımı ve
inşaatında daha doğru malzeme seçimlerinin yapılmasına ve daha güvenli yapıların oluşturulmasına katkı
sağlayacaktır.
Anahtar kelimeler: deprem, betonarme bina, beton, çelik, hasar analizi
Bu çalışmanın amacı, Diyarbakır kurak koşullarında artan dozlarda azotlu ve fosforlu gübrelemenin yakamoz buğday çeşidinde tane besin elementi içeriğine etkisinin belirlenmesidir. Tarla denemesi
Diyarbakır İli Silvan İlçesi çiftçi şartlarında tesadüf bloklarında faktöriyel deneme desenine göre üç tekrarlamalı olarak yürütülmüştür. Azotlu gübre 0, 4, 8 ve 12 kg N/da dozlarında amonyum sülfat formunda (%21 N) ve fosforlu gübre 0, 5 ve 10 kg P2O5/da dozlarında triple süper fosfat formunda (%42-44 P2O5) uygulanmıştır. Araştırma sonuçlarına göre, artan azot dozları buğday tanesinde N, P, Ca, Fe ve Cu içeriklerini önemli düzeyde etkilemiş, fakat tanede K, Mg, Mn ve Zn'ye etkisi önemli bulunmamıştır. Artan fosfor dozları tanede Mg ve Fe içeriklerini önemli düzeyde etkilemiştir.
Drying is one of the oldest food preservation methods. By reducing the water activity through drying, microbial
and enzyme activation is limited, thus extending the shelf life of foods. Until today, many methods have been
tried in drying fruits and vegetables. Very few of these are used to dry products in liquid form. Freezing,
spraying, and foam drying are used for drying products in liquid form. Foam drying involves first mixing the
liquid product with foaming agents into the foam form, and then drying it with any technique. Since the surface
area of the product, which is brought into the foam form, will increase, the drying time is reduced, thus the
nutritional content of the produced powder is preserved. This method is especially used for drying viscous and
sugary products. In this method, various foamers and stabilizers such as egg albumin, glycerol monostearate,
carboxymethyl cellulose, xanthan gum, whey protein, soy protein, milk, lecithin are used for stable foam
formation. The most commonly used method of foaming is whisking. The foaming agents used in the production of stable foam, the foam stabilizer, the structure of the food, as well as the whipping time also affect. In this
review, the mechanism of foam drying, foamers used to create foam, foaming techniques, and their use in the
fruit and vegetable industry are discussed.
Key words: Foam mat drying, drying methods, foaming agent, foaming stability
Garlic, onions, and leeks are vegetables that belong to the Allium family and are widely consumed all over the world. Leeks are grown in temperate regions of the world, including Europe, Asia, North America, and Africa. Turkey has an important place in terms of the production amount of leek and other Allium vegetables (garlic, onion, etc.). Along with other Allium vegetables, it ranks 2nd in the world in terms of production amount. Various studies have been conducted on the effects and popularity of Allium vegetable species on human health. Leeks, which are generally consumed fresh, are rich in potassium, iron, dietary fibers, phenolic acids, flavonoids and glucosinolates. It is rich in fructooligosaccharides and inulin, known as prebiotics. Leeks contain about 5% fructooligosaccharides and 3-10% inulin. The main flavonoid of leeks is kaempferol. It is known that the consumption of foods containing kaempferol prevents the development of cancer and cardiovascular diseases. Recent research has shown an association between the consumption of certain Allium species, particularly garlic and leeks, and a reduced incidence and risk of breast cancer. It has been shown that Allium species reduce the risk of cardiovascular disease due to their antithrombotic, antihypertensive, hypolipidemic, hypocholesterolemic and anti-hyperhomocysteinemia effects, antimicrobial, antiviral, antidiabetic, antiprotozoal, antioxidant, antispasmodic, anticarcinogenic, antimutagenic, antiasthmatic, antiamnesic, antiinflammatory, it has been reported by various studies that it has effects such as liver protective, neuroprotective, hypotensive, hypoglycemic, immunomodulatory, urease - xanthine oxidase inhibitor. In this article, the rich composition, cultivation, evaluation and health effects of the leek are discussed.
Keywords: Leek, health, composition
Mining activities can lead to the generation of large quantities of heavy metal laden wastes which are released in an uncontrolled manner, causing widespread contamination of the ecosystem. Though some heavy metals classified as essential are important for normal life physiological processes, higher concentrations above stipulated levels have deleterious effects on human health and biota. Bacteria able to withstand high concentrations of these heavy metals are found in the environment as a result of various inherent biochemical, physiological, and/or genetic mechanisms. These mechanisms can serve as potential tools for bioremediation of heavy metal polluted sites. This review focuses on the effects of heavy metal wastes generated from gold mining activities on the environment and the various mechanisms used by bacteria to counteract the effect of these heavy metals in their immediate environment.
Raw bentonite was characterised and employed for adsorption of Cs(I), Sr(II), Co(II) and U(VI) from aqueous solution. Batch adsorption methodology was applied to study the factors influencing the adsorption capacity of bentonite. Thermodynamic parameters, ΔH°, ΔS°, and ΔG°w ere calculated and revealed that the sorption process is spontaneous and has endothermic nature. The isotherm studies revealed that Langmuir is more applicable than Freundlich isotherm. The maximum sorption capacity (Q0) for the studied sorbent towards Cs (I), U(VI), Co (II) and Sr (II) was 50, 33.3, 25 and 14.29 mg/g, respectively. To overcome the aggregation for clay flacks of bentonite in column,-an innovative microcapsule of alginate enclosing with bentonite was developed and characterised for removal of these ions from multi-component solution. The results revealed that bentonite and bento-nite-alginate demonstrated high adsorption capacity at the same pH 5.5. The breakthrough curve had S-shaped profile. The breakthrough capacity of Cs(I), U(VI), Sr(II) and Co(II) was found to be 11.75, 11.1, 8.73 and 11 mg/g, respectively. The total capacity and the total removal percent, (R total %), were established to be 42.58 mg/g and 58.4%, respectively. The results showed that there are some great separation done by elution using 4 M NaNO 3 and 4 M HNO 3. ARTICLE HISTORY
The purpose of this study was to determine the concentrations and contamination level of heavy metals and metalloid (i.e., Zn, Fe, Cu, Mn, Pb and As) in sediment samples taken from a thermal power station's 5 km buffer area (Bandel thermal power station-BTPS) in West Bengal, India. The atomic absorption spectrophotometer (AAS) was used to determine the presence of heavy metals in soil samples. Heavy metal and metalloid concentrations such as Zn, Fe, Cu, Mn, Pb and As were studied using various contamination and pollution-related indexes such as geo-accumulation index, enrichment factor, contamination factor, contamination degree, modified degree of contamination index, and pollution load index, and spatial distribution was presented using interpolation technique. An ecological risk index for all metals and a forecasted ecological risk index are also used to investigate the impact of heavy metals on biological elements in the soil. ANOVA and the Kruskal-Wallis test were among the multivariate statistical procedures used. Hierarchical cluster analysis was used to estimate the spatial similarity of sample locations, and Pearson's correlation was used to determine the relationship between different metal concentrations and soil physico-chemical parameters. Almost all of the sample sites had soils of very good to medium quality, according to the study. All heavy metals at this research site, with the exception of arsenic and lead, behave as plant micronutrients. Furthermore, no heavy metal band, with the exception of As, had a consistent concentration. Almost all of the sampling locations had extremely low to very low levels of pollution.
Aiming to implement the Brazilian repository for disposal of low and intermediate level of radioactive wastes, the “Project RBMN” is being coordinated by CNEN. The repository is made of multiple barriers in order to prevent or retain the migration of radionuclides throughout these paths to the environment. Clays are used as backfill and coverage layers, which are the repository natural barriers. Recently, in Nuclear Technology Development Center (CDTN) a protocol for clay characterization was elaborated, and it was used the Brazilian bentonite as a reference. In this protocol are established some physical and chemical tests and their reference values that are essential for the characterization of materials to be used as backfill and coverage layers in the surface repository. This research intended to evaluate the applicability of this protocol to characterize soil without and with bentonite. The bentonite content added to the soil was 30%. The results were compared with the reference values of the protocol and literature for materials with similar mineralogical features. The results showed an increase of the specific surface and of the cation exchange capacity, as the result of the bentonite addition. The hydraulic conductivity is significant decreased by the addition of bentonite.
In the present era, due to various industrial developments, there is a need to use different applications of nuclear energy. But the leading challenge is the management of nuclear waste, which emits dangerous rays such as gamma rays. This research aim is to create a layer to be used as a protective coating against radiation in low-level waste landfills. In this paper, bentonite is used as a base material and red mud as an additive. Also, to determine the linear attenuation coefficient (µ), a combination of bentonite with 0, 15, 30, and 45% red mud with bentonite was used. To perform a linear attenuation coefficient test, the NaI (Tl) detector and the source of Co ⁶⁰ were used at two energy levels of 1173 and 1332 keV. The results of laboratory tests show that the addition of red mud has improved the parameter of the linear attenuation coefficient of radiation at both energy levels so that the energy level of 1173 keV and 1332 keV with the addition of 45% red mud has improved by 16 and 12%, respectively.
In this paper, the investigation of the structural and radiation shielding characteristics of natural bentonite and zeolite was presented. XRD (X-ray diffraction) and SEM (scanning electron microscopy) were used to examine the structural properties and morphologies of the minerals. The Electron-Photon Interaction Cross Sections 2017 (EPICS2017) library through EpiXS software was used to obtain the photon shielding properties-including mass attenuation coefficients, mean free paths, half-value and tenth-value layers, effective atomic numbers, and buildup factors for energy absorption and exposure. The ESTAR web program and SRIM code were used to obtain electron and ion stopping powers and ranges. The neutron removal cross-sections and the fast and thermal attenuation factors were obtained using the Phy-X/PSD, MRCsC, and NGCal software. The results showed that the zeolite grain sizes were typically smaller than 50 µm, while the bentonite grain sizes were larger reaching 100 µm. It was found that both materials were significantly composed of mordenite and montmorillonite. The photon shielding quantities for both materials showed similar MFP, HVL, and TVL values with different buildup factor values at large penetration depths. The high-energy charged particle range within both materials described similar trends and values. The range of alpha particles was significantly smaller than the average grain sizes for both materials. The fast neutron removal cross-sections of zeolite and bentonite were significantly higher than for typical soil values. Both natural materials may be suitable candidate ingredients for radiation shielding composites, especially due to their natural abundance and unique properties.
Mica group minerals have been utilized in various industries such as paint, cement, rubber, plastic, paper, automotive, cosmetics, textile, etc. due to their unique electrical, thermal, and mechanical properties. In this study, the radiometric properties of 58 mica samples collected from three quarries operated commercially in Turkey were investigated using gamma-ray spectroscopy with an HPGe detector. The average activity concentrations of ²²⁶ Ra, ²³² Th, and ⁴⁰ K analyzed in mica samples were found as 12, 44, and 2763 Bq kg ⁻¹ , respectively. The radon emanation coefficient and radon mass exhalation rate of mica samples varied from 4 to 22% with an average of 10% and 0.4–5.9 µBq kg ⁻¹ s ⁻¹ with an average of 2.6 µBq kg ⁻¹ s ⁻¹ , respectively. The radiological hazard caused by the utilization of mica samples as raw materials in the cement and concrete industry was evaluated for adults by calculating the gamma index and annual effective dose due to external exposure indoor. The study results revealed that there are no significant radiological hazards associated with the utilization of mica samples as building raw materials.
Exposure to gamma-rays is hazardous for humans and other living beings because of their high penetration through the materials. For this reason, shielding materials (usually lead, copper and stainless steel) are used to protect against gamma rays. This study’s objective was to prepare ceramic materials for gamma radiation shielding by using different natural bentonite clays. Gamma-ray attenuation performances of the prepared shielding materials at different thicknesses were investigated and evaluated for different gamma-ray energies from different standard point gamma radiation sources (²⁵¹Am, ⁵⁷Co, ¹³⁷Cs, ⁶⁰Co, and ⁸⁸Y). The mass and linear attenuation coefficients of the prepared ceramics vary between 0.238 and 0.443 cm² g⁻¹ and between 0.479 and 1.06 cm⁻¹, respectively, depending on their thicknesses. Results showed that these materials could be prioritized because of their evidential properties of gamma radiation protection in radiation applications.
The focus of the present research is on the exploitation of extractive waste to recover raw materials, considering the technological and economic factors, together with the environmental impacts, associated with extractive waste quarrying and dressing activities. The present study, based on a case history from Northern Italy (Montorfano and Baveno granite quarrying area), was intended to validate the presented interdisciplinary approach for evaluating economic and environmental impacts associated with extractive waste facility exploitation (from granite waste to products for the ceramic industry and by-products for the building industry). A shared methodology was applied to determine extractive waste characteristics (geochemistry, petrography, and mineralogy), waste volume (geophysical, topographic, and morphologic 3D characterization) and potential exploitable products and by-products. Meanwhile, a Life Cycle Assessment (LCA) was applied to determine the environmental impacts associated with the extraction and processing phases.
In this study, heavy metal concentrations in agricultural surface soil (0–5 cm) samples collected from the area around the Kangal lignite-fired thermal power plant were determined using energy-dispersive X-ray fluorescence spectrometry. Also, the pH values of agricultural soil samples were measured to assess the level of acidification. Geo-accumulation index (Igeo), enrichment factor (EF), contamination factor (CF), contamination degree (CD), modified contamination degree (mCD), and pollution load index (IPL) were estimated to assess the heavy metals pollution in soil samples. The average concentration of Fe, Ti, Mn, Cr, Ni, Zn, Zr, Co, Cu, Pb, As, Sn and Hg was found as 39,065 ± 5096, 2262 ± 738, 721 ± 119, 713 ± 236, 610 ± 199, 82 ± 37, 65 ± 26, 64 ± 19, 29 ± 3, 17 ± 7, 9 ± 7, 3 ± 1 and 2 ± 1 mg kg⁻¹, respectively. The values of pH varied from 7.5 to 8.2 with an average value of 8.0 (moderately alkaline). The Igeo, EF and CF results reveal that the study area is heavily or very highly contaminated with Cr, Ni, and Hg. On the basis of the IPL value, the soil samples are polluted with heavy metals. However, the mCD indicates moderate heavy-metal contamination of the soil samples.
Bentonite-based geomaterials are included in the designs of geological repository planning in most countries, especially in high-level radioactive waste disposal. Physical integrity of the bentonite sealant is key in assuring its hydraulic and retention properties, which affect the long-term performance of the repositories. Examination of the internal textures and structures of bentonite has been challenging until recently. Here, X-ray computed tomography (XCT) is applied to improve the textural and structural characterization of natural and man-made bentonite samples. Based on these initial analyses, clear benefits have been identified compared with conventional bentonite research methods. First, applying XCT prior to destructive analytical methods provides means to distinguish secondary features or in situ textures. It allows to eliminate false interpretations due to sample deformation and guides subsampling. Second, XCT images add the third dimension to analyses, allowing larger spatial coverage in less time. Overall, findings support the application of XCT for reducing uncertainties related to physical characterization of bentonite samples, both natural and industrial. They also show that XCT has potential to be developed to support quality assurance processes for bentonite sealant manufacturing.
Uranium (U) has no known essential biological functions. Furthermore, it is well known for its toxicity, radioactivity, and carcinogenic potency. Impacts on human health due to U exposure have been studied extensively by many researchers. Chronic exposure to low-level U isotopes (radionuclides) may be interlinked with cancer etiology and at high exposure levels, also kidney disease. Other important issues covered U and fertilizers, and also U in soils or human tissues as an easily measurable indicator element in a pathophysiological examination. Furthermore, phosphate fertilization is known as the important source of contamination with U in the agricultural land, mainly due to contamination in the phosphate rock applied for fertilizer manufacture. Therefore, long-term usage of U-bearing fertilizers can substantially increase the concentration of U in fertilized soils. It should also be noted that U is an active redox catalyst for the reaction between DNA and H2O2. This review is aimed to highlight a series on various hydro-geochemical aspects in different water sources and focused on the comparison of different U contents in the drinking water sources and presentation of data in relation to health issues.
Mining wastes containing sulfide minerals can generate contaminated waters as acid mine drainage (AMD) and contaminated neutral drainage (CND). This occurs when such minerals are exposed to oxygen and water. Nowadays, mineralogical work—when it is done—is independently and differentially done according to the needs of the exploration, geotechnics, metallurgy or environment department, at different stages in the mine development process. Moreover, environmental impact assessments (EIA) are realized late in the process and rarely contain pertinent mineralogical characterization on ores and wastes, depending on countries’ regulations. Contaminant-bearing minerals are often not detected at an early stage of the mine life cycle and environmental problems could occur during production or once the mine has come to the end of its productive life. This work puts forward a more reliable methodology, based on mineralogical characterization of the ore at the exploration stages, which, in turn, will be useful for each stage of the mining project and limit the unforeseen environmental or metallurgical issues. Three polymetallic sulfide ores and seven gold deposits from various origins around the world were studied. Crushed ore samples representing feed ore of advanced projects and of production mines were used to validate the methodology with realistic cases. The mineralogical methodology consisted in chemical assays and XRD, optical microscopy, SEM and EPMA were done. Five of the ores were also submitted to geochemical tests to compare mineralogical prediction results with their experimental leaching behavior. Major, minor, and trace minerals were identified, quantified, and the bearing minerals were examined for the polluting elements (and valuables). The main conclusion is that detailed mineralogical work can avert redundant work, save time and money, and allow detection of the problems at the beginning of the mine development phase, improving waste management and closure planning.
Lignite coal (LC) is a key energy source for electricity generation in Turkey. During lignite burning, huge amounts of fly ash (FA), bottom ash and slag are produced as by-products which contain radionuclides in the natural radioactive series of uranium and thorium, and radioactive potassium. These radionuclides may lead to radiological exposure of workers and the public and cause environmental problems. Therefore, finding diverse uses for the by-products in the construction sector and earthwork applications has considerable economic and environmental importance. In this study, the activity concentrations of
Thorium and uranium are constant components of all soils and most minerals thereby rock raw materials. They belong to the particularly dangerous elements because of their natural radioactivity. Evaluation of the content of the radioactive elements in the rock raw materials seems to be necessary in the early stage of the raw material evaluation. The rock formations operated from deposits often are accumulated in landfills and slag heaps where the concentration of the radioactive elements can be many times higher than under natural conditions. In addition, this phenomenon may refer to buildings where rock raw materials are often the main components of the construction materials. The global control system of construction products draws particular attention to the elimination of used construction products containing excessive quantities of the natural radioactive elements.
In the presented study were determined the content of thorium and uranium in rock raw materials coming from the Bełachatów lignite deposit. The Bełchatów lignite deposit extracts mainly lignite and secondary numerous accompanying minerals with the raw material importance. In the course of the field works within the framework of the carried out work has been tested 92 samples of rocks of varied petrographic composition. There were carried out analyses of the content of the radioactive elements for 50 samples of limestone of the Jurassic age, 18 samples of kaolinite clays, and 24 samples of siliceous raw materials, represented by opoka-rocks, diatomites, gaizes and clastic rocks. The measurement of content of the natural radioactive elements thorium and uranium based on measuring the frequency counts of gamma quantum, recorded separately in measuring channels. At the same time performed measurements on volume patterns radioactive: thorium and uranium. The studies were carried out in Mazar spectrometer on the powdered material. Standardly performed ten measuring cycles, after which were calculated the concentration of radioactive elements in the sample.
The highest concentration of thorium and uranium has been found in the clayey raw material. Their value was respectively from 8 to 12 mg/kg for thorium and from 2.3 to 3.5 mg/kg for uranium. In carbonate sediments the content of thorium was at the level from 0.5 to 2.1 mg/kg and uranium from 0.5-2.2 mg/kg. From a group of the siliceous raw materials the diatomite had a highest concentrations of radioactive elements where the content of thorium was from 1.5 to 1.8 mg/kg and uranium from 1.3 to 1.7 mg/kg.
Panasqueira mine is a tin–tungsten mineralization hosted by metasediments with quartz veins rich in ferberite. The mineralization also comprises wolframite, cassiterite, chalcopyrite, several sulfides, carbonates and silver sulfosalts. The mining and beneficiation processes produce arsenic-rich mine wastes laid up in huge tailings (Barroca Grande and Rio tailings). The contents of As, Cd, Cr, Cu, Pb and Zn were estimated in rhizosphere soils, irrigation waters, road dusts and in potatoes, cabbages, lettuces and beans, collected on local gardens of four neighborhood Panasqueira mine villages: S. Francisco de Assis (SFA) and Barroca suffering the influence of tailings; Unhais-o-Velho and Casegas considered as non-polluted areas. The mean concentrations of metals in rhizosphere soils and vegetables exceed the reference guidelines values and seem to be linked to the sulfides. The rhizosphere ecological risks were ranked in the order of Cd > As > Cu > Pb > Zn > Cr and SFA > Barroca > Casegas > Unhais-o-Velho. Metal concentrations, in vegetables, were found in the order of lettuce > cabbage > potatoes and SFA > Barroca > Casegas > Unhais-o-Velho. For cabbages and lettuces, the tendency of contamination is roots > leaves and for potatoes is roots > leaves > tubers. The risk for residents, due to ingesting of metals/metalloid, by consuming vegetables grown around the sampling area, was calculated and the result indicates that the inhabitants of these villages are probably exposed to some potential health risks through the intake of heavy metals and metalloids via consuming their vegetables.
The radioactive waste produced from the construction of a nuclear power plant is a controversial topic. The resulting radioactive waste contains ⁶⁰Co and ¹³⁷Cs isotopes that are the most difficult to remove. Bentonite is widely used as an adsorbent for heavy metals. An important factor is the safe operation of waste management at a nuclear power plant to be built in Vietnam. Therefore, a method of degrading complexes of radionuclides and the adsorption of radionuclides onto Vietnamese Bentonite was implemented in this study. In current literature, UV radiation and heating with oxidising substances are used in general for degrading complexes of radionuclides. The experimental results for the adsorption of Co(II) and Cs⁺ onto VNB suggest that VNB can be used in the future for large-scale liquid waste treatment due to its low cost, high efficiency, and environmentally friendliness.
The gold mining plant of Oman was studied to assess the contribution of gold mining on the degree of heavy metals into different environmental media. Samples were collected from the gold mining plant area in tailings, stream waters, soils and crop plants. The collected samples were analyzed for 13 heavy metals including vanadium (V), chromium (Cr), manganese (Mn), nickel (Ni), copper (Cu), cadmium (Cd), cobalt (Co), lead (Pb), zinc (Zn), aluminium (Al), strontium (Sr), iron (Fe) and barium (Ba). The water in the acid evaporation pond showed a high concentration of Fe as well as residual quantities of Zn, V, and Al, whereas water from the citizens well showed concentrations of Al above those of Omani and WHO standards. The desert plant species growing closed to the gold pit indicated high concentrations of heavy metals (Mn, Al, Ni, Fe, Cr, and V), while the similar plant species used as a control indicated lesser concentrations of all heavy metals. The surface water (blue) indicated very high concentrations of copper and significant concentrations of Mn, Ni, Al, Fe, Zn, lead, Co and Cd. The results revealed that some of the toxic metals absorbed by plants indicated significant metal immobilization.
A comprehensive study was conducted to determine thorium, uranium and potassium elemental concentrations in surface soils throughout the accessible area of Cyprus using high-resolution gamma-ray spectrometry. A total of 115 soil samples was collected from all over the bedrock surface of the island based on the different lithological units of the study area. The soil samples were air-dried, sieved through a fine mesh, sealed in 1000-ml plastic Marinelli beakers, and measured in the laboratory in terms of their gamma radioactivity for a counting time of 18 h each. From the measured gamma-ray spectra, elemental concentrations were determined for thorium (range from 2.5 x 10(-3) to 9.8 microg g(-1)), uranium (from 8.1 x 10(-4) to 3.2 microg g(-1)) and potassium (from 1.3 x 10(-4) to 1.9%). The arithmetic mean values (A.M. +/- S.D.) calculated from all samples are: (1.2+/-1.7 microg g(-1)), (0.6+/-0.7) microg g(-1), and (0.4+/-0.3%), for thorium, uranium and potassium, respectively, which are by a factor of three-six lower than the world average values of 7.4 microg g(-1) (Th), 2.8 microg g(-1) (U) and 1.3% (K) derived from all data available worldwide. The best-fitting relation between the concentrations of Th and K versus U and also of K versus Th, is essentially of linear type with a correlation coefficient of 0.93, 0.84 and 0.90, respectively. The Th/U, K/U and K/Th ratios (slopes) extracted are equal to 2.0, 2.8 x 10(3) and 1.4 x 10(3), respectively.
The activity concentrations of 232Th, 226Ra, and 40K in different pumice samples have been determined by high-resolution gamma-ray spectrometry using a 110% HpGe detector. The radium equivalent activities (Raeq), external hazard index (Hex), and internal hazard index (Hin) associated with the natural radionuclides and representative level index (Igamma r) are calculated to assess the radiation hazard of the natural radioactivity in the pumice samples. The mean values of the measured radioactivity concentrations of 232Th, 226Ra, and 40K for pumice samples from the region of lakes (ROL) are 232.4+/-8.0, 196.9+/-7.8, and 1325.8+/-20.4 Bqkg(-1) and for pumice samples from Cukurova region (CR) 16.3+/-4.0, 16.1+/-4.9, and 479.7+/-170.4 Bqkg(-1), respectively. The calculated Raeq values vary from 435.9+/-12.5 to 883.6+/-41.5 Bqkg(-1) with a mean of 630.9+/-20.2 Bqkg(-1) for the ROL samples and from 49.7+/-3.3 to 101.9+/-7.2 Bqkg(-1) with a mean of 76.3+/-23.7 Bqkg(-1) for the CR samples. For the ROL samples, Raeq are above the limit of 370 Bqkg(-1), equivalent to external gamma dose of 1.5 mSv yr(-1), recommended for the safe use of construction materials by NEA-OECD, while for the CR samples, Raeq values are lower than the limit.
Bentonite is a soft, porous, easily shaped, and absorbent material rich in aluminum, sodium, and potassium. Bentonite is a mineral widely utilized as drilling mud, ore pelletizing, absorbent/adsorbent, bleaching agent, water impedance, coating, and raw material in various industries. In this study, radiometric measurements of 90 bentonite samples collected from 21 quarries in Turkey were performed using gamma-ray spectrometry. The radiological hazards caused by indoor exposure to adults due to the utilization of bentonites as raw materials in the construction industry and outdoor external exposures to quarry workers were evaluated by estimating the activity concentration index, annual effective doses, and lifetime cancer risk. The average activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K measured in bentonite samples were found as (50 ± 5) Bq/kg, (76 ± 4) Bq/kg and (373 ± 19) Bq/kg, respectively. The evaluation results reveal that the bentonites examined could be safely utilized as raw materials.
The Cs- and Ba-sorption, onto bentonite from Kimolos island (Cyclades, Greece) was investigated in aqueous solutions in presence of Na⁺, Ca²⁺ and humic acid. Batch experiments were performed using as tracers ¹³⁷Cs and ¹³³Ba and γ-ray spectroscopy. The sorption significantly depended on initial concentration, ionic strength and temperature of the solutions. The sorption isotherms were satisfactorily reproduced by the Langmuir and Freundlich equations. The kinetic experiments at 293, 308 and 323 K and the calculation of the thermodynamic parameters (ΔH, ΔS˚ and ΔG°) indicated that Cs- and Ba-sorption were spontaneous and endothermic processes. The sorbent was characterized before and after the sorption experiments using Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), and scanning electron microscopy (SEM-EDS). It was demonstrated that the Kimolos bentonite is a good sorbent for cesium and barium from highly contaminated solutions and its sorption capacity reduced in presence of humic acid and competing cations.
The effectiveness ofthe use of zeolites in different industrial processes depends on their physical-chemical properties that are distinctly connected to their geological deposits. In this study, major oxides, eco-toxic metals (Cr, Co, Ni, Cu, Zn, As, Zr, Cd and Pb), and rare earth (Y, La, Ce, Pr and Nd), radioactive (Th and U) and other trace elements contents of eighty-one zeolite samples collected from four different zeolite quarries in Gördes in Turkey were analysed by using energy dispersed X-ray fluorescence spectrometer. Also, pH values and SiO2/Al2O3 ratios were determined for zeolite samples. In addition, radiogenic heat generation (RHG) caused by radiations emitted from uranium (U), thorium (Th) and radioactive potassium (⁴⁰K) in zeolite samples wereestimated.Gördes zeolite contains major oxides, on average, 75.1% SiO2, 14.1% Al2O3, 3.2% K2O, 2.4% CaO, 1.7% Fe2O3, 1.4% MgO, 1.3% Na2O. The average concentration of As, Cd, Pb, Th and U analysed in zeolite samples were found as 24.8, 2.1, 47.830.1 and 6.0 mgkg⁻¹, respectively. According to average SiO2/Al2O3 ratios, the ZO1 quarry contains middle silica zeolites while ZO2, ZO3 and ZO4 quarries contain high silica group zeolites. RHG values estimated for zeolite samples varied from 2.3 µWm⁻³to 4.1 µWm⁻³.
The consumption of bottled natural mineral water has become more popular in Turkey due to the faith about the helpful medicinal and therapeutic impacts of mineral waters including various dissolved minerals. However, mineral water derived from groundwater contains natural radioactive radon gas which is one of the important sources of natural radiation. In this study, the activity levels of radon in forty-nine bottled natural plain and fruit-flavoured mineral water samples of twenty-two commercially brands sold in Turkish markets were determined using an active radon gas monitoring system. The pH, conductivity, salinity, and total dissolved solids of mineral water samples were also measured using standard laboratory methods. The total annual effective dose due to ingestion and inhalation of radon in mineral water samples was estimated for infants, children, and adults to assess the health risk caused by internal exposure. The activity concentrations of radon measured in mineral water samples varied from 30.6 to 57.6 mBq L⁻¹ with an average of 43.1 ± 6.1 mBq L⁻¹. The average total annual effective dose was found as 0.42, 0.26 and 0.36 µSv for infants, children and adults, respectively. All measured radon concentrations and estimated annual effective dose values are within the within recommended limits by the WHO and European Union for drinking water. It can be concluded that the effective radiation dose from the radon in bottled natural mineral water samples investigated is very low and creates a negligible health risk for the public.
Simultaneous adsorption of Zn(II) and Hg(II) in the presence of alkaline earth metal, Mg(II) on dithizone-immobilized bentonite has been done by batch method. The study was begun by activation of natural bentonite with HCl followed by immobilization of dithizone on bentonite surface. Some parameters influencing the adsorption such as pH, interaction time and initial concentration of metal ions were optimized. Types of interaction between metal ions and adsorbent were assessed by conducting sequential desorption of the adsorbed metals using H2O, KNO3, HONH2HCl and Na2EDTA. XRD and FTIR characterizations suggest that dithizone has been successfully immobilized on the surface of bentonite. Optimum conditions for simultaneous adsorption of Hg(II) and Zn(II) in the presence of Mg(II) are at pH 6 and interaction time of 60 minutes. Capacity, affinity and selectivity of dithizone immobilized bentonite towards Hg(II) and Zn(II) are better than those of non-immobilized activated natural bentonite, but the interaction types of the two metal ions with adsorbents are different. Zn(II) ion mostly interacts with adsorbents through physical and electrostatic interactions, while Hg(II) ion interacts via hydrogen bond and complexation. Upon immobilization of dithizone on the surface of bentonite, the interaction of Hg(II) with adsorbent changes significantly from hydrogen bond to complexation. Moreover, the presence of Mg(II) ion gives no significant influence on metal adsorption, indicating that dithizone-immobilized bentonite is quite selective towards heavy metal ions.
Due to the high hydrophobicity and surface area, clays are efficient adsorbents for the removal of liquid impurities and purification of gases when they are modified. In this work, bentonite was modified with imidazole and imidazolium groups and resulting clays were characterized by different techniques such as ¹H NMR, ¹³C NMR, TEM, SEM, XPS, TG, and FT-IR. Applications of these clays were studied in the removal of Co, Cu, and Pb in the wastewater. Effects of contact time, pH, initial heavy metal ions concentration, and kinetic were investigated. The catalytic activity of the metals adsorbed by imidazole modified bentonite was studied in A³ coupling reactions of various amines, aldehydes, and alkynes.
Field -ray spectrometry was used for the quantitative assessment of radioactive elements and the expected radon ux of rocks cropping out at the Alps–Apennines transition zone (NW Italy). The spatial variation in radioelement concentration reeects, in general, the geochemical diierences among the analysed rocks. Rocks of the ophiolitic complex clearly diier in K, U, and Th concentrations from sedimentary and metasedimentary rocks. The lowest U concentration (¡ 0:5 ppm) was found in tectonic units mainly formed by rocks of maÿc composition. The average U concentration increases to 2.6 –4:1 ppm in shales of diierent units and calc-schists, and it is highest (5:6 ppm) in the dolomitic rocks. Shales and phyllitic schists of pelagic origin show the highest Th concentrations. The expected radon exhalation from the decay of 226 Ra within the 238 U decay series is, consequently, lower in the ophiolitic rocks (0.7–2:2 Bq m −2 h −1) and higher in calc-schists and dolomites (18.4 –20:7 Bq m −2 h −1). The estimated radon ux is also signiÿcant in shales and phyllites (15.1–18:4 Bq m −2 h −1).
The evaluation of the abundances of chemical elements in the Earth’s crust is a pivotal geochemical problem. Its first solutions
in the early 20th century formed the empirical groundwork for geochemistry and justified concepts about the unity of the material
of the Universe, the genesis of the chemical elements, and the geochemical differentiation of the Earth. The accumulation
of newly obtained data called for the revision of this problem, and a series of papers by A.P. Vinogradov, which were published
in Geokhimiya in 1956–1962, presented reevaluated contents of elements in the continental crust. In these papers, A.P. Vinogradov relied
on the classic idea of the geochemical balance of the sedimentary process. These generalizations provided the foundation for
the quantitative characterization of the geochemical background of the biosphere and allowed Vinogradov to formulate the principles
of the melting and degassing of material in the outer Earth’s shells during the geologic history, a concept that became universally
acknowledged in modern geochemistry and geology. The composition of the Earth’s crust can also be evaluated based not on the
principle of geochemical balance in the sedimentary process but on data on the actual abundances of major magmatic, metamorphic,
and sedimentary rock types. The possibility of this solution was provided after the extensive research of A.B. Ronov, who
managed to develop a quantitative model for the structure of the Earth’s sedimentary shell. Based on these data, A.B. Ronov,
A.A. Yaroshevsky, and A.A. Migdisov published a series of papers in Geokhimiya in 1967–1985 that presented a model for the chemical structure of the Earth’s crust with regard for the material composing
not only the upper part of the continental crust but also its deep-seated granulite-basite layer and the oceanic crust. The
quantitative estimates thus obtained led the authors to important conclusions: first, it was demonstrated that the estimated
abundances of elements in the granite-metamorphic layer of the continental crust presented in the classic works by A.P. Vinogradov
are confirmed by independent materials, which are based on data on the actual abundance of rocks. Second, incredible as it
was, the principle of geochemical balance in the sedimentary process in application to Ca and carbonates appeared to be invalid.
This problem remains unsettled as of yet and awaits its resolution.
Elevated levels of naturally occurring uranium in groundwater have been found in small geographic areas throughout the world. Relevant research was reviewed pertaining to natural and depleted uranium (DU) exposure and nephrotoxicity, including epidemiologic community-based and occupational studies, studies of Gulf War veterans exposed to DU, and experimental studies in animals. Occupational cohort studies do not provide evidence of an increased risk of kidney-related mortality among uranium-exposed workers. However, occupational and community-based studies of populations chronically exposed to elevated drinking-water concentrations of uranium provide some evidence of adverse renal effects, as assessed by biomarkers of proximal tubule damage such as urinary levels of glucose, calcium, and various low-molecular-weight proteins. Indications of proximal tubule effects, as evidenced by increased urinary β(2)-microglobulin and retinol binding protein levels, were also seen in the most recent follow-up surveillance study of Gulf War veterans exposed to DU. The reported β(2)-microglobulin levels in these studies were generally considered to be within normal limits, but the long-term implications of the observed variation in these levels are not established. The kidney was observed to be a target of uranium toxicity following oral and implantation exposure routes in several animal species. The interpretation and importance of the observed changes in biomarkers of proximal tubule function are important questions that indicate the need for additional clinical, epidemiological, and experimental research.
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