Total Element Concentrations Research Articles

Particulate matter and potentially toxic element content in urban ornamental plant species to assess pollutants trapping capacity.

Urban environments are usually polluted by anthropogenic activities like traffic, a major source of potentially toxic elements (PTEs), and ornamental plant species may reduce contamination by trapping traffic-related air pollutants in their leaves. The purpose of this study was tested the trapping pollutant capacity of four species commonly used in green areas of Seville city (SW Spain) to better choose species in urban green planning. Composition of particulate matter (PM) obtained from foliar surfaces (sPM) and wax-included (wPM) was determined by EDX-SEM analysis in samples from different city locations. Concentration of different PTEs (Ba, Cd, Cr, Cu, Fe, Mn, Ni, Pb, V and Zn), by microwave induced-plasma optical emission spectroscopy (MP-AES) were also analyzed in unwashed leaves of one of the selected species (Citrus aurantium) since it is the most cultivated species in Seville. Results showed that Nerium oleander was the plant species which trapped best superficial total and coarse PM. This capacity was enhanced by the presence of a waxy-cuticle and by cuticle thickness but not by leaf hairs. The only species unable to trap fine particles was Bougainvillea glabra. The most representative sPM on leaf surfaces from all species was the largest fraction (59-75%), followed by coarse (25-37%) and fine fractions (2.2-4.4%). In the wax PM, 48% of coarse particles were found in Citrus aurantium. Particulate matter deposited on surface foliage in general did not vary seasonally, while the large fraction of wPM in summer was significantly higher than in winter. The seasonal differences also existed in the level of PTE (Cd, Fe, Ni and V) in leaves. This work indicates that the leaf traits should be taken into account to evaluate the pollutants caption capacity, especially when planning of recreational green urban areas. Particulate matter composition was different according to the pollution sources and mostly contained Al, C, Ca, Fe, K, and Mg, but potentially toxic elements such as Si, As, Cr, Cu and Zn just accounted for 0.11-1.95% of the total elemental content.

Potentially harmful elements in mining sites in Ghana: assessment of their carcinogenic and non-carcinogenic health risks for children and adults

PurposePotentially harmful elements (PHEs) in the soil at gold mining sites can endanger the health and sustainability of the local community. We examined the potential health risks associated with the presence of PHEs (Al, Cd, Cu, Fe, Hg, Mn, Pb, Sb, Se and Ti) in the soils of active, closed/abandoned/former and profile gold mine sites in Ghana.Design/methodology/approachWe collected 102 soil samples from these mine sites, analysed them for their total element contents and calculated the geo-accumulation index, enrichment factor, contamination factor and pollution load index (PLI) (Igeo). We calculated the risks to human health by utilizing the hazard index (HI) and hazard quotient (HQ) for adult males, adult females and children who may ingest contaminated soil particles.FindingsThe average total Cd concentration in the soils was above the global average of 0.2 mg/kg for abandoned (2.86 mg/kg), active (3.93 mg/kg) and profile (4.04 mg/kg) areas. Mercury was detected at elevated concentrations in the soil of active mines (0.92 mg/kg), profiles (0.89 mg/kg) and abandoned mines (0.87 mg/kg). In the active, abandoned and profile soils, titanium concentrations were 14.18, 6.74 and 4.82 mg/kg, respectively, in several folds above the global average of 0.57 mg/kg. The majority of the sites were contaminated with Cd, Hg and Ti based on the calculated PLI values (active = 2.04, abandoned = 1.77 and profile = 2.7). Cadmium, mercury, lead and titanium in mine spoils were found to be correlated with aluminium, iron, manganese, pH, total carbon, clay content and phosphorus in a multivariate analysis using correlation and principal component analysis.Research limitations/implicationsBoth natural and anthropogenic processes contributed to the elevated metal contents in the mining sites, as indicated by the investigation’s results. The children’s hazard index values exceeded the threshold of 1.0, indicating the presence of non-carcinogenic risks.Practical implicationsGreen space technology (e.g. revegetation) may thus be critical for preserving public health and reviving the ecological integrity of the contaminated sites.Originality/valueThis study highlights health risks to local communities in southwest Ghana by investigating the presence of potentially harmful elements in soils from gold mining sites for the first time. It assesses non-carcinogenic and carcinogenic health risks using a methodology recommended by the US Environmental Protection Agency for soil-to-human health risk assessment, especially for children. The study highlights how contamination has been found, making green space technology essential for preserving ecological integrity and protecting public health. The inclusion of geospatial distribution mapping of PTEs offers a visual depiction of the spread of contamination at both active and closed mining sites.

Nutritional Risks of Heavy Metals in the Human Diet-Multi-Elemental Analysis of Energy Drinks.

Background: In recent years, the consumption of energy drinks (EDs) by adolescents and young adults has increased significantly, so concerns have been raised about the potential health risks associated with excessive ED consumption. Most analyses on EDs focus on the caffeine content. Research on the content of minerals (essential and toxic) in energy drinks can be considered scarce. Therefore, there is a need for research stating the actual status of heavy metal content in commercially available energy drinks. Methods: This research presents the determination of the total concentrations of macro-elements and trace elements (TEs), such as Na, K, Mg, Ca, Al, Cr, Co, Cu, Fe, Mn, Ni, B, Zn, V, Sr, Ba, Pb, Cd, and As in nine samples of energy drinks using inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS) techniques. Results: The order in the content of macro-minerals in the EDs was as follows: Na > K > Mg > Ca. The results showed that ED 1, ED 3, and ED 7 samples had the highest micro-mineral concentrations. All the samples had a hazard quotient and hazard index < 1, indicating no non-carcinogenic risk from exposure to single or multiple heavy metals in both the adolescent and adult age groups. Some samples exceeded the threshold limit of acceptable cancer risk for As, Ni, and Cr in both adolescents and adults. Conclusions: This assessment showed that in addition to health implications based on the caffeine content of EDs, there might be a carcinogenic risk associated with the toxic element content of these beverages. This research also highlights notable differences in the TE levels among various ED brands, which may have important implications for consumer well-being and health.

Quantification of the Total and Extractable Content of Micro- and Trace Elements in Linden Blossom and Infusions—The Impact of Urban Pollution on Health Risk for Samples from Plovdiv, Bulgaria

Linden (Tilia) is one of the most frequently utilized plants for the preparation of infusions because of its salutary effects, including the reduction in inflammatory processes and pain, alleviation of stress, and lowering of blood pressure. As Linden is a common species in Bulgarian cities, it is frequently used for homemade infusions. The regular consumption of these tea beverages may contribute to the attainment of the recommended daily allowances of certain minerals, but it may also result in the accumulation of toxic elements within the human body. The present study compares the concentrations of essential and toxic elements in linden blossom collected from disparate locations in Plovdiv, Bulgaria, with those of samples gathered in ecologically pristine regions and commercially available products labeled “bio”. Both total element content and extractable forms in infusions were quantified by ICP-MS. The health risk due to consuming infusions was assessed by comparing the water, tea, drinks, and EFSA regulations. The applied cluster analysis divided the samples from the urban area into three groups related to traffic pollution. In spite of the short blooming period, the concentrations of Al, Fe, Pb, V, Cr, Co, Ni, and Cd in the samples from the most polluted areas are increased by a factor of two compared to those from the clean zones.

Mineralogical Characteristics and Purification Experiments of Quartz from a Pegmatite: A Case Study in the Lushi Region of the Qinling Orogenic Belt, Central China

This study uses a sample of pegmatite (LS-1) from the Longquanping deposit in Lushi County, Henan Province, to evaluate its potential as a valuable source of HPQ. This investigation uses various analytical techniques to assess the quality of quartz and its suitability for industrial applications. The methods used in this study include optical microscopy, scanning electron microscopy (SEM), Raman spectroscopy, X-ray fluorescence spectrometry (XRF), laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), and inductively coupled plasma mass spectrometry (ICP-MS) to analyze the petrographic, mineralogical, and trace element characteristics of quartz before and after purification and comprehensively evaluate the potential of quartz in these rocks as an HPQ raw material ore. The optical and scanning electron microscopic observations reveal several impurities and associated minerals in quartz, including feldspar, biotite, magnetite, sphene, and large number of fluid inclusions composed of both gas and liquid phases. The content of trace element in raw quartz ore in the LS-1 sample as determined by LA-ICP-MS analysis ranges from 41.61 to 256.13 ppm, with the main impurity elements being Al, Ti, Li, Na, K, and Ca. After purification, the SiO2 contents and total trace elements contents of the LS-1 refined quartz sand was 99.997 wt.% and 29.29 ppm, respectively, with Al (13.29 ppm), Ti (4.20 ppm), Li (1.15 ppm), and Na (10.32 ppm). The major trace element contents of Al and Ti in the quartz concentrates were lower than the upper limit of the HPQ standard and thus belonged to the high-end products (4N8). Results of this study show that quartz from a pegmatite in the Lushi region has the potential to be purified HPQ. This study underscores the importance of thorough mineralogical and elemental analyses in assessing the suitability of quartz raw material deposits for HPQ production.

Size and density separation for concentrating critical elements in ash fractions

ABSTRACT Coal and lignite ash are emerging as significant sources for extracting rare earth elements (REEs) and critical minerals. Despite lower concentrations of critical elements in ashes, their preconcentration is crucial for enhancing extraction efficiency and reducing energy consumption. Additionally, the simultaneous extraction of base metals could render combustion residue a more appealing raw material alongside the critical elements. Lignite fly ash samples from Neyveli, India, were analyzed using physical separation methods to preconcentrate critical elements. The total rare earth element (REE) content, including Y (REY, 1057 mg/kg) and Sc (REY-Sc, 1086 mg/kg) and the outlook coefficient (1.35), exceeded the cutoff value for economic extraction. Ga content was found to be comparable to that in bauxite residue, used for Ga extraction in India. REEs showed their greatest concentrations in the finer and lighter fractions. In contrast, TiO2, Fe2O3, Gd, Er, Lu, Ba, Cd, CO, Cu, Ga, Mn, Mo, Nb, Ni, and Pb tended to concentrate in the denser fractions. A flow diagram was presented that outlined the preconcentration process for base metals (Fe, Ti) and critical elements within designated ash fractions.

Investigation on the structure formation, morphology, electronic and magnetic properties of BaFe12O19 nanopowders synthesized by utilizing sol-gel technique using L-sorbose as a fuel agent

Hexagonal barium ferrite (BaFe12O19) is a highly magnetic material due to its high resistivity, large permeability and low loss behaviour. It was mainly focused on applications in the electric, magnetic and telecom industries because of their good dielectric properties at microwave frequencies. The brown colored nanoparticles (NPs) of BaFe12O19 were carried out by the sol-gel approach using L-sorbose as a fuel synthesized from the ethylene glycol and oxalic acids. The synthesized nanopowders were characterized by thermal, X-ray diffraction (XRD), scanning electron microscopy (SEM), FT-IR, photoluminescence (PL), ultraviolet visible (UV–Vis), energy dispersive spectroscopy (EDS), cyclic voltammetry (CV) and vibrating sample magnetometer (VSM) techniques. XRD peak indicates the formation of good quality nanocrystalline hexagonal BaFe12O19 phase of the synthesized sample. The FT-IR spectra exhibited the significant vibrational frequencies of BaFe12O19 NPs were detected at 448, 578 and 768 cm−1 for 800 °C, which suggests the formation of a hexagonal phase. The SEM images of BaFe12O19 powders at 800 °C indicated the micro-sized flakes shape with crystallite size ranging from 40 to 65 nm. The EDS was performed to analyze the total energy distributions and elemental individual content of the prepared powders and it was also found that the content of Ba reduced as the content of Fe increased. Further, the physical properties of the synthesized NPs were determined by VSM analyzer and the high saturation magnetization (Ms = 18.41 emu/g), remanence magnetization (Mr = 10.20 emu/g) and magnetization coercive force (Hc = 5707 Oe). Overall, these results suggested the prepared nanoparticles calcined at 800 °C have the good potential for utilization in many applications such as magnetic recording, fast random access memory, electronic devices, etc.

Raman spectroscopy combined with active hyperspectral sensing for classification of waste plastics containing brominated flame retardants: A sensor fusion approach.

Discrimination of waste plastics according to brominated flame retardant (BFR) concentration is essential to ensure quality and safety in recycling. We present a sensor fusion approach to classify BFR-containing plastic waste by combining Raman and near-infrared (NIR) spectroscopies. We analysed 210 waste plastic samples sourced from waste electronics and electrical equipment stream and 25 laboratory-made plastics. The Raman spectra were acquired in the range 27-2481 cm-1 using a time-gated Raman and the NIR spectra in the range 4000-5260 cm-1 using a novel active hyperspectral sensor. Total elemental bromine concentrations were determined with X-ray fluorescence spectroscopy and used as reference for training extremely randomized trees classifiers for high- and low-bromine plastics with different thresholds of segmentation. The classifier models were built using Raman and NIR spectral data after reducing dimensions with principal component analysis, both separately and by fusing the data. We achieved over 80% balanced classification accuracies using all models, with significant improvements by data fusion.

Regional differences in soil stable isotopes and vibrational features at depth in three California grasslands

There are major gaps in our understanding of how Mediterranean ecosystems will respond to anticipated changes in precipitation. In particular, limited data exists on the response of deep soil carbon dynamics to changes in climate. In this study we wanted to examine carbon and nitrogen dynamics between topsoils and subsoils along a precipitation gradient of California grasslands. We focused on organic matter composition across three California grassland sites, from a dry and hot regime (~ 300 mm precipitation; MAT: 14.6 ∘C) to a wet, cool regime (~ 2160 mm precipitation/year; MAT: 11.7 ∘C). We determined changes in total elemental concentrations of soil carbon and nitrogen, stable isotope composition (δ13C, δ15N), and composition of soil organic matter (SOM) as measured through Diffuse Reflectance Infrared Fourier Transformed Spectroscopy (DRIFTS) to 1 m soil depth. We measured carbon persistence in soil organic matter (SOM) based on beta (β), a parameter based on the slope of carbon isotope composition across depth and proxy for turnover. Further, we examined the relationship between δ15N and C:N values to infer SOM’s degree of microbial processing. As expected, we measured the greatest carbon stock at the surface of our wettest site, but carbon stocks in subsoils converged at Angelo and Sedgwick, the wettest and driest sites, respectively. Soils at depth (> 30 cm) at the wettest site, Angelo, had the lowest C:N and highest δ15N values with the greatest proportion of simple plant-derived organic matter according to DRIFTS. These results suggest differing stabilization mechanisms of organic matter at depth across our study sites. We infer that the greatest stability was conferred by associations with reactive minerals at depth in our wettest site. In contrast, organic matter at our driest site, Sedgwick, was subject to the most microbial processing. Results from this study demonstrate that precipitation patterns have important implications for deep soil carbon storage, composition, and stability.

Soil-forming factors controlling Technosol formation in historical mining and metallurgical sites in the high-alpine environment of the Tatra Mountains, southern Poland

The Tatra Mountains are a unique Central European alpine ecosystem where the non-anthropogenic soil cover and soil-forming processes are well recognized. However, the Technosols in the area’s high-mountain environment have not been studied in detail to date. Therefore the aim of this study was to identify the most important soil-forming factors controlling the properties of Technosols developed in historical mining and metallurgical sites in the Tatra Mountains of southern Poland active from the 15th Century until the end of the 19th. The present paper is one of the first attempts to study the genetic aspects of high-mountain Technosols in the temperate climatic zone. The study involved determining soil morphology and classification, soil properties, magnetic susceptibility, mineral composition, optical microscopic observations and total concentration of major elements. The studied Technosols were poorly developed soils with simple soil morphology (mainly A horizon in the topsoil and C horizons in the subsoil). There was a high content of rock fragments. The research has shown that the properties of Technosols in the Tatra Mountains were primarily determined by past human activities like mining and metallurgy as well as the type of anthropogenic parent material, which included mining wastes and metallurgical slags and determined soil properties together with mineral and chemical composition. Soil formation was significantly influenced by vegetation which was conditioned by the relief and climatic conditions dependent on altitudinal zonation. Vegetation and plant-derived soil organic matter shaped topsoil properties. The lengthy soil-forming process acting since a few centuries in some Technosols led to the formation of Bw horizons.

Facilitation of microbialite development by continental weathering in the Cambrian Zhangxia Formation, southern North China Block

We report geochemical data for carbonate rocks from the Cambrian Zhangxia Formation, southern North China Block, including trace-element contents and C, O, and Sr isotopic compositions, to determine the controls on the development of microbialites in this formation. The sedimentary environment of the Zhangxia Formation evolved from carbonate-slope through platform-margin-reef to ooid-shoal, and then to open-platform settings, corresponding to the development of micrites, microbialites, and oolitic limestones. Geochemical data show that δ13C values decrease upwards through the Zhangxia Formation, from 0.99‰ to −1.59‰, whereas δ18O values increase from −9.91‰ to −7.10‰. Total rare earth element (REE) contents decrease upwards through the stratigraphy, and the contents of Th and Sc show a similar trend. 87Sr/86Sr ratios reach a maximum of 0.710544 in the horizons of microbialite development, Member 2 of the Zhangxia Formation, above which the ratios are uniform, with a mean value of 0.709251. Combining these geochemical data with the inferred sedimentary evolution, the Zhangxia Formation is interpreted to have formed in a depositional environment that changed from transgression to regression. Continental weathering played a crucial role in promoting the input of terrigenous materials, which in turn favored the development of microbialites during the early stage of deposition of the Zhangxia Formation.

Copper, lead, and zinc tolerance and accumulation in the Australian rattle pods Crotalaria novae‐hollandiae, C. medicaginea, and C. mitchellii

AbstractCrotalaria is a genus of ~600 species of legumes predominantly found in (sub)tropical regions of Africa and Australia. Crotalaria novae‐hollandiae from Australia is a polymetallic zinc (Zn)‐cadmium(Cd)‐copper(Cu) hyperaccumulator, but only when growing in metalliferous soils. This study aimed to test metal tolerance in Australian Crotalaria species to establish whether metal tolerance is a trait shared between Crotalaria species not known to occur on metalliferous soils. The hyperaccumulator Crotalaria novae‐hollandiae and two non‐metallophytes, Crotalaria mitchellii and Crotalaria medicaginea, were exposed to different treatments containing Cu‐lead(Pb)‐Zn in the form of spiked soils. Foliar samples were analyzed for total elemental concentrations and spectrophotometric analysis was undertaken to assess photosynthetic pigments (chlorophyll a + b and carotenoids) as indicators of stress and polyphenols as an indicator of tolerance. No significant differences in metal accumulation were found in the Crotalaria species, and all exhibited a high level of tolerance toward Zn. However, C. novae‐hollandiae exhibited the greatest tolerance toward Zn but had low tolerance toward Cu, while none accumulated foliar Pb. Tolerance to Zn appears to be a trait shared between the Crotalaria species tested. None of the tested Crotalaria species exhibited tolerance toward Cu, and none accumulated Pb.

Do probiotics and iron supplementation have any impact on element distribution in rat kidneys? – bioimaging by laser ablation inductively coupled plasma mass spectrometry

This study investigates the influence of multistrain probiotics and iron supplementation on the distribution and interaction of trace elements in the kidneys of Wistar rats using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) bioimaging. Forty 6-week-old female Wistar rats were divided into five groups, each fed an AIN-93 M diet with varying additions or deficiencies of iron and probiotics, which included a control, an iron-deficient diet, an iron-deficient diet with probiotics, an iron-deficient diet with iron supplementation, and an iron-deficient diet with both probiotics and iron supplementation. The obtained two-dimensional maps of the distribution of elements reveal distinct locations of Cu, Fe, Mn, and Zn in specific tissues of rat kidneys. Specifically, Cu and Fe were co-localized in the renal cortex, while Zn was mostly absent from regions where Cu and Fe accumulated. Fe supplementation alone increased Fe in the renal cortex, while probiotics enhanced this effect, suggesting a synergistic role in Fe absorption. The total content of elements in the kidneys of all groups was determined after digestion: Cu 13.3–24.7 mg kg−1, Fe 218–509 mg kg−1, Mn 0.87–1.29 mg kg−1, and Zn 28.6–40.1 mg kg−1. Competitive interactions among Cu, Fe, and Zn were observed, with probiotics modulating their concentrations and distribution, highlighting their role in trace element homeostasis. Our research provides insights into the interactions between dietary supplements, probiotics, and trace element distribution in kidneys, paving the way for targeted nutritional interventions. This study highlights the need for further research on trace element functions in organisms and their impact on health.

Rubidium (Rb) enrichment processes in a highly evolved granitic system: Insights from the petrology and geochemistry of the Guobaoshan Rb deposit in eastern Tianshan, NW China

Highly fractionated granitoids are closely associated with Rb mineralization, yet the mechanisms that control Rb enrichment and details about the enrichment process have not been well constrained. The Guobaoshan Rb deposit in eastern Tianshan, NW China, is one of the largest granite-related Rb deposits; it preserves a series of gradual lithofacies ranging from biotite granite and muscovite granite to Rb-rich amazonite granite and pegmatite, and provides an excellent opportunity to constrain the Rb enrichment processes in granitic systems. The large Guobaoshan Rb deposit hosts 281,000 tons of Rb2O at a grade of 0.12% mainly in its amazonite-bearing granite and amazonite granite lithofacies. In this contribution, we integrate geochronology, bulk-rock geochemistry, and analysis of Nd and zircon Hf isotopes to characterize the evolution of the Guobaoshan granitic pluton and the mechanisms that generated Rb enrichment. The zircon U-Pb age of the biotite granite and columbite U-Pb age of the amazonite granite are 244.8 ± 1.8 Ma (1σ, mean square of weighted deviates [MSWD] = 1.1) and 241.9 ± 2.3 Ma (1σ, MSWD = 1.0), respectively. In situ Rb-Sr analysis of orthoclase, mica, and albite from the amazonite-bearing granite, amazonite granite, and pegmatite yields ages of 249.1 ± 7.3 Ma (2σ, MSWD = 1.6), 245.5 ± 16.8 Ma (2σ, MSWD = 0.63), and 245.8 ± 9.8 Ma (2σ, MSWD = 3.3), respectively. Together, these ages demonstrate that the Guobaoshan granitic pluton formed during the Triassic and underwent a protracted magmatic evolution. The Guobaoshan granitic pluton is characterized by high concentrations of SiO2, alkalis, and Al2O3, and low concentrations of MgO, Fe2O3, CaO, P2O5, and TiO2, with an Al saturation index (A/CNK) of 1.01−1.14. It is enriched in Rb, but depleted in Ba, Sr, P, and Eu, has low total rare earth element (REE) contents (83.1−221 ppm), and is characterized by significantly negative anomalies (Eu/Eu* = 0.01−0.44). The biotite granite is enriched in light rare earth elements (LREEs), whereas the muscovite granite, amazonite-bearing granite, amazonite granite, and pegmatite are depleted in LREEs, and exhibit a marked tetrad effect (TE1.3 = 1.05−1.50). These geochemical characteristics, combined with the non-CHARAC (charge-radius−controlled) ratios of Zr/Hf, Nb/Ta, Y/Ho, and K/Rb, are indicative of melt-fluid interaction during the evolution of the Guobaoshan magma. Given that the biotite granite is the least-evolved rock, its petrological and geochemical characteristics suggest that it is an I-type granite. The slightly variable εHf(t) and consistently negative εNd(t) values indicate that the magma from which the Guobaoshan granitic pluton crystallized was likely sourced from the Mesoproterozoic crust, with limited mantle contributions. The coeval ages and coherent geochemical variations and mineral compositions of these rocks suggest that they formed via fractional crystallization of plagioclase, mica, quartz, and K-feldspar in the same magmatic system. This is supported by fractional crystallization simulations using the rhyolite-MELTS software package. Based on the petrological, mineralogical, and geochemical characteristics of the muscovite granite, amazonite-bearing granite, amazonite granite, and pegmatite, as well as simulations using rhyolite-MELTS, high degrees of fractional crystallization of granitic magma and interaction of this evolving magma with F-rich fluids are suggested to have been the key mechanisms that caused enrichment of Rb, while the melt-fluid interaction was more critical for Rb mineralization.

Research on 4N8 High-Purity Quartz Purification Technology Prepared Using Vein Quartz from Pakistan

This study investigates the potential of two quartz vein ores from the Hunza District, Gilgit-Baltistan, Pakistan, as raw materials to obtain 4N8 high-purity quartz (HPQ) sand. Various quartz purification processes were examined, including ore calcination, water quenching, flotation, sand calcination, acid leaching, and chlorination roasting. Analytical techniques such as optical microscopy, Raman spectroscopy, and inductively coupled plasma spectroscopy were employed to analyze the microstructure, inclusion characteristics, and chemical composition of both the quartz raw ore and the processed quartz sand. Microscopic observation reveals that the PK-AML quartz raw ore has relatively high purity, the secondary fluid inclusions are arranged in a directional–linear manner or developed along crystal micro-cracks, and most intracrystalline regions exhibit low inclusion contents, while the PK-JTLT quartz raw ore contains a certain number of melt inclusions. The two processed quartz sand samples exhibit a smooth surface with extremely low fluid inclusion content. A comparative analysis of different purification processes shows that quartz sand calcination has a higher impurity removal rate than ore calcination. After crushing the raw ore into sand, the particles become finer with a larger specific surface area. Quartz sand calcination maximally exposes the inclusions and lattice impurity elements within the quartz, facilitating subsequent impurity removal through acid leaching. Following the processes of crushing, ultrasonic desliming, flotation, sand calcination, water quenching, acid leaching, and chlorination roasting, the SiO2 content of PK-AML processed quartz sand is 99.998 wt.%, with only a small amount of Ti and Li remaining, and a total impurity element content of 20.83 µg·g−1. This meets the standard requirements for crucible preparation in industrial applications, making this vein quartz suitable for producing high-end HPQ products. In contrast, the overall purity of PK-JTLT quartz is lower, and the high contents of impurity elements such as Li, Al, and Ti are difficult to remove via purification experiments. The SiO2 content of PK-JTLT processed quartz sand is 99.991 wt.%, which is applied to higher-quality glass products such as photovoltaic glass, electronic glass, and optical glass, thus presenting broad prospects for application.

Do red marine carbonates represent oxic environments? New understanding from the Upper Ordovician marine limestone in Tarim Basin, China

Marine red beds (MRBs), typically colored by Fe- and Mn-rich minerals, are often interpreted as indicators of bottom water oxygenation. However, their continuous formation requires long-term input of aqueous derived Fe-Mn oxides and/or stable sources of Fe2+ and Mn2+ ions, challenging the traditional concept of “red equals oxic environment.” This study investigates two coeval Upper Ordovician Sandbian MRB carbonate intervals in the Tarim Basin. Previous studies attributed the pigment origin to hematite. Th/U values and total rare earth element and yttrium (REY) contents increased in the MRB interval, indicating a terrestrial source of iron. Hematite was observed within the intercrystal pores of calcite precipitating from porewater, consistent with high Nicarb abundance and MREE-enriched bulge pattern in the red intervals. Both sections exhibit high Fecarb and Mncarb, pointing to substantial reductive dissolution of Fe and Mn oxides. Simulation shows that isotopic discrimination (Δ13C) between carbonate and organic carbon could be biased by increasing benthic Fe-Mn flux, leading to decreased Δ13C values in MRB intervals. Ce/Ce∗ values in the high-Mncarb interval reflect the releasing of Ce by reductive dissolution of Mn oxides. The commonly used carbonate-based redox proxy I/(Ca + Mg) ratio is correlated positively with Mncarb in the shallower section and with TOC in the deeper section, while it is negatively correlated with TOC in the shallower horizon, suggesting that iodine behavior may be influenced by adsorption and releasing of Mn hydro-oxides and organic matter besides oxygen contents. This study links MRB coloring to Fe and Mn mineral cycling in pore water through reductive dissolution and oxidative precipitation, and highlights potential biases of carbonate-based redox proxies that might be susceptible to other electron acceptors/donors such as Fe-Mn oxides and organic matter, in addition to free oxygen in seawater.

Petrogenesis and tectonic setting of the proto-tethyan dachaidan ophiolite, North China: insights from clinopyroxene chemistry and whole-rock Sr–Nd–Pb and zircon Hf isotopes

IntroductionThe Dachaidan ophiolites outcrop within an ultrahigh-pressure metamorphic belt along the northern margin of the Qaidam Basin. However, their age, source, and tectonic setting remain still in debate.MethodIn this study, we investigated the geochemistry and geochronology of the Dachaidan ophiolitic gabbros.Results and DiscussionZircon U–Pb dating yielded a crystallization age of 510.0 ± 2.8 Ma and 510.0 ± 2.9 Ma for the gabbro. The gabbros have low SiO2 contents (47.15–50.10 wt.%) and high MgO contents (6.35–9.04 wt.%) and Mg# values (55–74). The total rare earth element (∑REE) contents are 8.35–28.07 ppm, lower than those of normal-type mid-ocean ridge basalts (MORBs), and the gabbros exhibit light REE depletion or flat REE patterns, with small positive Eu anomalies (Eu/Eu* = 1.06–1.40). Trace element patterns are depleted to enriched in Nb and Ta, similar to island arc rocks and MORB. Clinopyroxene thermobarometry indicates the parental magma of the gabbros formed by high-temperature (1,318°C–1,363°C) and medium-pressure (1.27–1.64 GPa) partial melting in a mantle wedge. The gabbros have depleted Sr–Nd–Pb-Hf isotopic compositions, with (87Sr/86Sr)i = 0.704586–0.707441, εNd(t) = 4.7–6.6, and zircon εHf(t) = 7.6–11.4. The age-corrected Pb isotope ratios of these volcanic rocks are variable, with 206Pb/204Pb(t) = 18.085–18.253, 207Pb/204Pb(t) = 15.595–15.614, and 208Pb/204Pb(t) = 37.880–38.148, which are similar to the isotopic compositions of typical Indian MORBs. The source of the Dachaidan ophiolite is inferred to have been depleted mantle. The Dachaidan ophiolite likely formed in a forearc oceanic setting along the northern margin of the Qaidam Basin, during the initial subduction of an oceanic plate.

Petrogenesis and tectonic setting of granitic pegmatites in the Beishan orogenic Belt, Northwest China: Evidence from geology, geochronology and geochemistry

The Weiboshan (Li-, Cs- and Ta-enriched) LCT-type Nb–Ta deposit located in Ejin Banner, Inner Mongolia, represents a newly discovered pegmatite-type rare metal deposit of significant interest. In this paper, we describe the petrography and present new mineralogical and whole-rock geochemical data and zircon U–Pb ages of ore-related granitic pegmatites in this deposit. Pegmatite dikes can be divided into three distinct zones on the basis of their contents: the K-feldspar graphic granite pegmatite zone (Kf), microcline graphic granite pegmatite zone (Mic), and albite–muscovite granite pegmatite zone (Ab). The pegmatite dikes and associated mineralization formed during the Mesozoic. Granite pegmatites in various zones display distinctive geochemical features characterized by high silicon contents, substantial alkali enrichment, and relatively low iron, calcium, and magnesium levels. These pegmatites are classified as peraluminous or quasialuminous and exhibit low total rare earth element concentrations. Notably, these pegmatites are enriched in large ion lithophile elements (LILEs), such as Rb, K, and U, but depleted in high field strength elements (HFSEs), such as P and Ti. The progression from the Kf to Mic to Ab zones signifies the thorough evolution of the granitic magma, where the late-stage near-hydrothermal system assumed a crucial role in the mineralization of rare metals during magma differentiation. The Weiboshan pegmatites, which exhibit syncollisional attributes, are A-type granites formed through crustal partial melting induced by decompression. This process occurred against the background of postorogenic extension driven by asthenospheric mantle upwelling resulting from lithospheric delamination due to crustal collision and thickening.

Fate and impact at molecular level of diatrizoic acid and iohexol contrast agents in Dreissena polymorpha mollusks.

Iodinated contrast media (ICMs) used in X-ray imaging for medical diagnostics are released into wastewater and then encountered in river water at concentrations ranging from several dozen to hundreds of µg/L, and even thousands of µg/L in hospital effluents. ICMs are considered as emerging pollutants as their occurrence and impact on ecosystems and the environment are poorly documented. Even if they are considered inert for humans, aquatic organisms are continuously exposed to ICMs, and their potential deleterious effects are therefore questioned as we have recently demonstrated that they enter into organisms such as the zebra mussels. To answer this question, Dreissena polymorpha were exposed to two ICMs of different osmolality, diatrizoic acid and iohexol, at an environmental concentration (100µg/L) for 21days before a depuration phase of 4days. The occurrence, fate, and impact of both ICMs in these organisms were studied using a metallomic approach. Thus, iodine as well as endogenous copper and zinc were quantified and analyzed in cytosolic extracts of digestive glands, gills, and gonads of mussels by size exclusion chromatography coupled to ICP MS. This work shows that a subcellular fractionation is necessary to distinguish variations in total element content. The cytosolic iodoprotein chromatographic pattern was consistent for the three organs and confirmed the presence of ICMs in cytosols. Additionally, this exploratory work tends to show a weak biological effect of ICMs with a substantial variation of the profile of Cu-binding proteins mostly in the gill cytosol and to a lesser extent, in the digestive gland cytosol.

Distribution and in situ bioaccumulation test of radioecologically relevant metals in boreal freshwater sediments

Sediments act as important sinks for metals and their radionuclides in aquatic environments and play a crucial role in their transfer and uptake to aquatic organisms. Traditional radioecological models use radionuclide concentrations in water to predict concentrations in aquatic organisms. In this study, we investigated the distribution of radioecologically important metals (Ba, Co, Ni, Sr, U) among sediment, porewater and hypolimnion over seasons. We also studied the uptake of these metals to benthic organisms and importance of sediment as an uptake source by conducting a 28-day in situ bioaccumulation experiment with oligochaete worms (Lumbriculus variegatus). The studied metals were chosen based on common occurrence of their radioactive isotopes in nuclear fuel cycle. Measurements of total elemental concentration were used as proxies to study the behavior of specific radionuclides. Sediment and water samples were collected from two small lakes connected to a former uranium mine in Eastern Finland, and from a nearby reference lake connected to a different drainage area. Environmental characteristics and concentrations measured from sediment, porewater and overlying water indicated only minor changes between seasons. Measured metals were highly associated with sediment particles, rather than porewater or hypolimnion. Both the distribution of metals and in situ experiment indicated the importance of sediment as the main source of bioaccumulation. Significant differences in Ba, Ni and U concentrations between treatments containing contaminated sediment and reference sediment were noted, regardless of water concentrations. Additionally, as U contaminated lakes lacked seasonal overturn during our monitoring period, metal distribution and environmental conditions remained unchanged in deeper parts of those lakes. Lastly, the results of this in situ bioaccumulation experiment are in line with the findings of our previous laboratory study using sediments from these same lakes.