Rb Concentrations Research Articles

Urinary Levels of 14 Metal Elements in General Population: A Region-Based Exploratory Study in China.

Metal pollution may lead to a variety of diseases; for this reason, it has become a matter of public concern worldwide. However, it is necessary to use biomonitoring approaches to assess the risks posed to human health by metals. In this study, the concentrations of 14 metal elements in 181 urine samples obtained from the general population of Gansu Province, China, were analyzed using inductively coupled plasma mass spectrometry. Eleven out of fourteen target elements had detection frequencies above 85%, namely, Cr, Ni, As, Se, Cd, Al, Fe, Cu and Rb. The concentrations of most metal elements in the urine of our subjects corresponded to the medium levels of subjects in other regional studies. Gender exerted a significant influence (p < 0.05) on the concentrations of Tl, Rb and Zn. The concentrations of Ni, As, Pb, Sr, Tl, Zn, Cu and Se showed significant differences among different age groups and the age-related concentration trends varied among these elements. There were significant differences in the urine concentrations of Zn and Sr between those subjects in the group who were frequently exposed to soil (exposed soil > 20 min/day) and those in the group who were not, indicating that people in regular contact with soil may be more exposed to metals. This study provides useful information for evaluating the levels of metal exposure among general populations.

Magma Composition and Formation Conditions of Alkaline-Salic Rocks of the Early Mesozoic Adaatsag Bimodal Association of the Kharkhorin Rift Zone, Central Asia: Data from the Study of Melt Inclusions in Minerals

The composition and formation conditions of magmas of comendites of the Early Mesozoic Adaatsag volcanic association are determined using electron and ion microprobe analysis of melt inclusions, and mechanisms favorable for the accumulation of trace and rare earth elements are identified. The melt and fluid inclusions are found in quartz of comendites sampled in various parts of the section of a volcanic sequence. The melt inclusions consist of glass, a gas bubble, and daughter minerals (fluorite, polylithionite, and K-feldspar). The composition of a gas phase in melt inclusions was studied using Raman spectroscopy. The dominant gas phase components include water and hydrogen. The fluid inclusions are aqueous fluids probably corresponding to KF. The thermometric studies of melt inclusions and the analysis of glasses of homogenized melt inclusions in quartz phenocrysts of comendites showed that magmas crystallized from water-saturated rare metal melts with high Li, Zr, F, Rb, Nb, Y, and Th contents at a temperature of 880–930°C and a pressure of 1000 bar at a depth of ~3.5 km accompanied by degassing. The comparison of our data of the study of melt inclusions in phenocrysts of alkaline salic rocks of the coeval Adaatsag, Dzarta-Khuduk, and Sant volcanic associations, which occur within the Kharkhorin Rift Zone, revealed common principles of magma evolution. This allowed us to propose a similar mechanism of their formation, involving the accumulation of many rare and rare-earth elements, as well as volatile components (F, H2O) in the process of crystallization differentiation. Subsequently, a salt melt rich in Li, F and water could be separated from such comendite magmas. The detection of fluoride aqueous inclusions in quartz allows us to suppose the further evolution of the salt melt leading to the appearance of a concentrated aqueous fluid and the possible participation of the latter in metasomatic processes.

In-situ trace element and Li-isotope study of zinnwaldite from the Degana tungsten deposit, India: Implications for hydrothermal tungsten mineralization

Zinnwaldite, a Li, Rb-mica is a common magmatic or hydrothermal mineral in many tungsten deposits. In this study, we use the trace element and Li-isotope composition of zinnwaldite from Degana, the largest tungsten deposit of India, to constrain the source and evolution of the ore fluid, the precipitation mechanism of W and the roles of fractional crystallization, fluid exsolution and fluid-rock interaction in the mineralization process. Textural evidence suggests that the mineralization in the Degana rocks involved at least two stages of fluid infiltration. The earlier of the two was multi-pulsed and responsible for the primary tungsten and zinnwaldite mineralization. The second hydrothermal stage caused partial dissolution and reprecipitation of both wolframite as well as zinnwaldite, reflected in the patchy zones that replace both minerals. The ore fluid had high concentration of Li, Rb, Cs, Nb, and Ta as evident from zinnwaldite chemistry. The δ7Li of the ore fluid (+14 to +19 ‰), estimated from the Li-isotope composition of zinnwaldite in mineralized veins (δ7Li = +12 to +17‰), is significantly heavier compared to upper/middle continental crust, ruling out the possibility of a metamorphic fluid source. The high concentration of incompatible elements including Cs, extremely low K/Rb (10–15), is best explained by its growth from fluids exsolved from an enriched, late-fractionated granitic melt. Alteration of the host granite, formation of greisen, large-scale albitization and muscovitization are indicative of fluid-rock interaction, which might have increased the fluid pH, destabilizing fluoride complexes of W, resulting in the precipitation of wolframite. The shift in the chemical and Li-isotope composition from the early mica to late altered ones in the greisen indicates interaction of the hydrothermal fluid with the host rocks. A U-Pb Concordia age of 838 ± 9 Ma retrieved from magmatic domains of zircon from the Degana granite dates it emplacement and represents the maximum age of the W-mineralization.

English

The study aimed to assess concentrations of heavy metals in soil samples on both sides along the three Niles (Blue, White, and Nile Rivers) and Almogran area (Tuti Island) in Khartoum city (the capital of Sudan country) after the overflow season. Concentrations of heavy metals Br, Cu, Ni, Pb, Co, Rb, Cr, Zn, Zr, Sr, Mn, Ti, K, Ca, and Fe were determined using Xray fluorescence (XRF) techniques compatible with direct analysis of soils. The results showed that the element's concentration along the Blue Nile is higher than White Nile, Nile river, and Almogran area. In addition, Enrichment Factor (EF) and Geoaccumulation index (GI) factor was calculated, and both are in recommended ranges except EF for Ni high at Blue Nile 2.58, which is more than recommended value (2).

Two Distinct Fractional Crystallization Mechanisms of A-Type Granites in the Nanling Range, South China: A Case Study of the Jiuyishan Complex Massif and Xianghualing Intrusive Stocks

The petrogenesis of A-type granites with different occurrences in the Nanling Range remains unclear. In this study, a case study of the Jiuyishan complex massif and Xianghualing intrusive stocks was conducted to determine this problem. The Jiuyishan complex massif is composed of four units (Jinjiling, Pangxiemu, Shaziling and Xishan). These four units have similar zircon U-Pb ages of approximately 153 Ma, with high Zr + Nb + Ce + Y contents (&gt;350 ppm), high 10,000 Ga/Al ratios (&gt;2.6), and a high crystallization temperature, indicating A-type affinities. They show a gradual change in lithology and geochemistry, implying a fractional crystallization process. These units also have similar εNd(t) values (−8.2 to −5.8) and zircon εHf(t) values (−7.5 to −2.2) except for the Shaziling MMEs (mafic microgranular enclaves) (−14.2 to 4.8), demonstrating their lower crustal source. However, the Shaziling unit may have contributed mantle-derived magma based on the geochemical data of its hosted MMEs. In comparison, the two Xianghualing intrusive stocks have similar geochemical features but exhibit highly evolved features (high Rb, U, Y, Ta and Nb contents and low Eu, Ba, Sr, P, Ti, Ca, Mg and Fe contents, with V-shaped REE distribution patterns). They have different zircon U-Pb ages of approximately 160 Ma and 155 Ma. The two stocks also have similar whole-rock εNd(t) values (−6.5 to −5.7) and zircon εHf(t) values (−7.6 to −2.7) and equally illustrate a lower crustal source region. Combining with their vertical zonation, they may have experienced remarkable fractional crystallization with possible assimilation processes. We propose that the Jiuyishan complex and Xianghualing stocks have two distinct fractional crystallization mechanisms during their formation. The Jiuyishan complex was formed by in situ crystal mush fractionation, while the Xianghualing stocks were formed by flowage differentiation during magma ascent or gravitational settling during magma solidification after emplacement. However, more than one mechanism affected the fractional crystallization processes of these granitic rocks.

The occurrence of anthophyllite–phlogopite-bearing schist in the Seridó belt, northeastern Brazil: Geological significance and potential guide of prospecting for gold and emerald deposits

In the Bonfim W–Mo and Au–Bi–Te skarn deposit, Northeastern Brazil, Archean metamafic–ultramafic rocks are similar to those found in greenstone belt sequences worldwide. The Bonfim emerald deposit comprises metric layers of lenticular-shaped phlogopite-rich schist developed at the symmetrical contacts between metamafic–ultramafic rocks and Be-rich granite intrusions. They formed near these rocks by metasomatic fluids emanating from granitic magma. Metasomatism also transformed the marble and schists into skarns at the marble–schist contact and within the marble. This contribution describes the drill cores containing Mg-rich schist in the Neoproterozoic metapelitic sequence. Detailed petrographic observations and geochemical analysis reveal that it contains phlogopite, anthophyllite, fuchsite, and anomalous Cr–Ni–V–Co–Sc contents. These characteristics contrast those of the common schists at Bonfim or regionally and indicate a probable komatiitic affinity. The anthophyllite–phlogopite-bearing schist contains a metamorphic paragenesis of phlogopite + anthophyllite + garnet + tourmaline + zircon + monazite + plagioclase + quartz, followed by two successive retrograde metasomatic parageneses comprising (i) clinozoisite–zoisite + apatite and (ii) white mica (±fuchsite) + clinochlore + quartz. It exhibits a peculiar texture containing prismatic pseudomorphs (1–7 mm long) composed of anthophyllite, clinozoisite–zoisite, and white mica. The relict orthogonal cleavage suggests that they could represent preexistent Mg-rich pyroxene. Similar to the common schist in Bonfim, the anthophyllite–phlogopite-bearing schist near the skarns is metasomatically converted in places into actinolite–anthophyllite–phlogopite-bearing schist. The anthophyllite–phlogopite-bearing schist contains phlogopite and biotite with low Fe/(Fe + Mg) (between 0.2 and 0.4) and anthophyllite with a composition close to Mg5Fe2Si8O22(OH)2 (MgO approximately 22 wt% and Al2O3 <0.7 wt%). In the actinolite–anthophyllite–phlogopite-bearing schist, the metasomatically formed amphibole has a composition varying from actinolite to magnesiohornblende with a high MgO (>16.5 wt%). The whole-rock geochemical analyses of three representative samples indicate that the anthophyllite–phlogopite-bearing schist contains high MgO (approximately 15%), Cr (up to 574 ppm), and Ni (up to 237 ppm) contents, besides V (up to 198 ppm), Co (up to 51 ppm), and Sc (up to 25 ppm). The anthophyllite–phlogopite-bearing schist has higher MgO, K2O, S, Cr, Co, Ni, and Rb contents, and lower Na2O, P2O5, Zn, Sr, Zr, and Pb contents than the average composition of the Seridó regional schist. The 87Sr/86Sr ratio in two representative samples of the Bonfim schists revealed that the anthophyllite–phlogopite-bearing schist has higher ratio (0.89455) than the enclosing common schist (0.74514), indicating distinct ages of the source rocks for the sedimentary protolith of these two schists, with evidence for an older age of the former source. The original sediments of the anthophyllite–phlogopite-bearing schist could have had an Archean komatiitic source (e.g., komatiitic basalt, peridotite, websterite or pyroxenite), as indicated by the Mg-rich metamorphic minerals (phlogopite and anthophyllite), Cr–K-rich metasomatic ones (fuchsite), and the peculiar MgO, Cr, Ni, Co, Sc, and K2O contents. This source could be part of an Archean greenstone belt now dismantled and/or removed by tectonic and erosion processes. Alternatively, the Mg-rich schist could be a remnant of the upper sedimentary unit of such an ancient rock sequence. The unusual schist could potentially guide gold and emerald deposit prospecting in the region.

X-ray Diffraction and Trace Element Analyses of K/Pg Boundary Samples Collected from Agost and Caravaca, Spain

The boundary between Cretaceous and Paleogene (K/Pg) plays an important role in deciphering the Earth’s history and biological evolution from Mesozoic to Cenozoic. As such, the delineation and characterization of the boundary layer has attracted significant attention. In this study, X-ray diffraction (XRD) and elemental analyses were conducted to characterize the samples of boundary layer and the layers around Agost and Caravaca, Spain. The XRD results showed that the layers immediately above and below the boundary layer are made of limestone, while in the boundary layer, a significant increase in the clay minerals smectite, kaolinite, and illite was observed. The major element analyses revealed an increase in Si and Al contents, confirming the presence of clay minerals. The trace element analyses showed elevated concentrations of V, Cr, Ni, Zn, Pb, and Th, but not for Rb, Cu, and U. The rare Earth element (REE) analyses showed elevated La, Ce, and Nd concentrations in the boundary layer. Correlation analyses between selected trace elements and REE showed good agreements, with R2 values of about 0.9. The results agreed well with the finding in the area, except the lower contents of Rb, Cu, and U; thus, they may promote further studies to make detailed comparisons.

Long-lived magmatic evolution and mineralization resulted in formation of the giant Cuonadong Sn-W-Be polymetallic deposit, southern Tibet

The Cuonadong Sn-W-Be polymetallic deposit is the first Cenozoic leucogranite-related rare-metal deposit with giant metallogenic potential in the Himalayan orogen. However, the controlling factors for the supernormal enrichment of beryllium, tin and tungsten in this deposit remain vague. In this study, we carried out systematic geochronological, whole-rock geochemical, and Sr-Nd isotopic analysis for the Cuonadong leucogranites, as well as detailed ore-forming geochronological study for the rare-metal mineralization. The monazite U-Th-Pb, cassiterite U-Pb and muscovite Ar-Ar dating results, together with previously reported geochronological data, indicate that the major Cuonadong leucogranites (including, from old to young, the weakly-oriented two-mica granite, two-mica granite and the muscovite granite) were formed during ∼ 21–15 Ma, whereas the Sn-W-Be mineralization mainly occurred at ∼ 18–14 Ma. The Cuonadong leucogranites show strong peraluminous (A/CNK = 1.09–1.22) features, and have high SiO2 (71.62–75.97 wt%) and Al2O3 (14.04–16.09 wt%) and low MgO (0.07–0.33 wt%), MnO (0.01–0.15 wt%) and total iron (Fe2O3T = 0.36–1.01 wt%) contents, and are enriched in large ion lithophile elements (e.g., Rb, U, K, and Pb). These geochemical features, together with enriched Sr-Nd isotopes (εNd(t) = -15.7 to −11.7; (87Sr/86Sr)i = 0.71957–0.76313), indicate that the Cuonadong leucogranites belong to S-type granite and were derived from muscovite-induced dehydration melting of metapelites of the Higher Himalayan Crystalline Sequence. Perceptible linear variations of some major elements (e.g., Na2O, K2O, MnO, Fe2O3T, TiO2 and A/CNK) with increasing Rb/Sr ratios suggest that these leucogranites experienced different degrees of evolution. Quantitative simulation calculations based on the whole-rock Rb, Sr, and Ba contents imply that the Cuonadong leucogranites experienced increasingly-strong fractional crystallization of plagioclase, K-feldspar and biotite from the weakly-oriented two-mica granite through the two-mica granite to the muscovite granite. Importantly, intense fractional crystallization leaded to notable enrichment of Sn, W and Be, although these elements are not obviously high in the relatively primitive magma for the Cuonadong leucogranites. Significantly, evident REE tetrad effects and deviation of twin-element pair ratios (e.g. K/Rb, K/Ba, Zr/Hf, Nb/Ta, and Y/Ho) from the chondritic values demonstrate that intense interaction between melts and volatile-rich aqueous fluids occurred during magmatic evolution. This implies that the Cuonadong leucogranites were derived from a volatile-rich magmatic system. The abundant volatiles probably facilitated occurrence of fractional crystallization and extended duration of this process through lowering the solidus and viscosity of the magma. Thus, we propose that the long-lived fractional crystallization (21–15 Ma) and rare-metal mineralization (18–14 Ma) collectively leaded to supernormal enrichment of Sn, W, and Be in the Cuonadong Sn-W-Be polymetallic deposit. In contrast, the enrichment of these rare-metal elements was insignificant during partial melting.

Highly sensitive and selective fluorescence sensor based on zirconia nanotube array films for Cu2+ detection

ZrO2 nanotube array films (ZNA) were prepared by anodisation method, and ZNA was modified with γ-aminopropyltriethoxysilane (APTES) to prepare amino-functionalized ZNA (ZNA-NH2). Through immobilizing Cu2+ ions and RB on ZNA and ZNA-NH2, the detection of Cu2+ ions could be realized by measuring the change of fluorescence intensity of RB, and the effects of APTES and RB concentrations on the detection performances were studied. The results show that the fluorescence detection performances of ZNA-NH2 carrier are significantly better than those of ZNA. The best detection performances for Cu2+ ions are achieved with the RB concentration of 10 mg/L and the APTES concentration of 0.4 M. The minimum detection limit is 0.68 nM (S/N = 3), and the linear range is from 1 × 10−3 to 3 × 102 μM under the optimal experimental conditions. The carriers can be regenerated and reused after being soaked in acetic acid solution. This work can be applied to the detection of Cu2+ ions in real seawater.

Differences of Relationships between Iodine and Trace Elements in Normal Thyroid and Thyroid Benign Nodules Revealed by X-Ray Fluorescent Analysis

Thyroid Benign Nodules (TBN) are the most common lesions of this endocrine gland. The etiology of TBN is not clear. The aim of this exploratory study was to examine differences in the content of bromine (Br), cooper (Cu), iron (Fe), iodine (I), rubidium (Rb), strontium (Sr), and zinc (Zn), as well as I/Br, I/Cu, I/Fe, I/Rb, I/Sr, and I/Zn content ratios in tissues of normal thyroid and TBN. Thyroid tissue levels of seven Trace Elements (TEs) were prospectively evaluated in 105 apparently healthy persons and in 79 patients with TBN. Measurements were performed using 109Cd and 241Am radionuclide-induced energy-dispersive X-ray fluorescent analysis. Tissue samples were divided into two portions. One was used for morphological study while the other was intended for TEs analysis. It was observed that in TBN the mass fraction of Br, Cu, and Fe were higher, whereas mass fractions of I as well as I/Br, I/Cu, I/Fe, and I/Zn mass fraction ratios were lower than in normal tissues of the thyroid. These changes can potentially be used as TBN markers. Furthermore, it was found that the levels of Br, Cu, Fe, Rb, Sr, and Zn contents in the normal and affected thyroid gland were interconnected and depend on the content of I in thyroid tissue. Because I plays a decisive role in the function of the thyroid gland, the data obtained allow us to conclude that, along with I, at least such TEs as Br, Cu, Fe, Rb, and Zn, if not directly, then indirectly, are involved in the process of thyroid hormone synthesis.

Indicators of restoration strategies in land uses: metallic and non-metallic elements

Land management practices can have an impact on the environmental quality of soil and contribute to identifying the source of its pollution. The objective of this study was to determine presence of metallic and non-metallic elements as indicators of land use impact (livestock management, restoration strategies and without management practices) in the Monte Caldera communal lands located in Cerro de San Pedro, San Luis Potosi, Mexico. Eighteen samples were collected at depths of 0-10 cm and 10-20 cm for each land use. Total concentrations of Zr, Sr, U, Th, Pb, As, Rb, Cr, V, Ti, Zn, and Cu were determined by X-ray fluorescence. Mean concentrations ranged in the following order: Ti&gt;Zr&gt;Rb&gt;V&gt;Sr&gt;Zn&gt;Cr&gt;Pb&gt; Cu&gt;Th&gt;U&gt;As, with concentrations for Ti, Cr, Th, U and As exceeding technical reference values for phytotoxic soils. Significant differences were evidenced by ANOVA between land use (Th, Pb, Rb, Cu) and soil depth (U, Pb, and As). Land use practices associated with restoration resulted in a positive environmental impact. These findings underscore the need to conduct follow-up studies in the area and further examine the relationship of such practices with other environmental factors. Highlights: Soil management practices can affect the environmental quality of this resource and help diagnose the source of its contamination. It is necessary to evaluate the Impact of land use on livestock management, restoration strategies, and without management or conservation areas. By X-ray fluorescence technique the total concentration of Zr, Sr, U, Th, Pb, As, Rb, Cr, V, Ti, Zn, and Cu was determined. Ti, Cr, Th, U and As exceed the technical reference values for consideration as phytotoxic in soils. Land use associated with reclamation practices is an indicator of a positive influence on improving soil quality.

Relationships between iodine and some trace elements in normal thyroid of females investigated by neutron activation analysis

Thyroid diseases rank second among endocrine disorders, and prevalence of the diseases is higher in the elderly as compared to the younger population. An excess or deficiency of trace element contents in thyroid play important role in goitro- and carcinogenesis of gland. The correlations with age of the ten trace element (TE) contents (Ag, Co, Cr, Fe, Hg, Rb, Sb, Sc, Se, and Zn), I/Ag, I/Co, I/Cr, I/Fe, I/Hg, I/Rb, I/Sb, I/Sc, I/Se, and I/Zn content ratios, and inter relationships between TE contents and I/TE content ratios in normal thyroid of 33 females (age range 3.5–87 years) was investigated by instrumental neutron activation analysis. Our data reveal that the Co, Rb, Sb, Se, and Zn content increase, while the I/Co content ratio decrease in the normal thyroid of female during a lifespan. Therefore, a goitrogenic and tumorogenic effect of excessive Co, Rb, Sb, Se, and Zn level in the thyroid of old males and of disturbance in intrathyroidal I/Co relationships with increasing age may be assumed. Furthermore, it was found that the levels of Ag, Co, Cr, Fe, Hg, Rb, Sb, Se, and Zn in the thyroid gland are interconnected and depend on the content of I in it. Because I plays a decisive role in the function of the thyroid gland, the data obtained allow us to conclude that, along with I, at least such TEs as Co, Cr, Fe, Rb, Sb, Se, and Zn, if not directly, then indirectly, are involved in the process of thyroid hormone synthesis.

The different responses of trace elements to equilibrium and disequilibrium melting: Implications for crustal differentiation and granite compositions

Equilibrium and disequilibrium meltings are two common mechanisms in the geochemical differentiation of the continental crust. However, responses of trace elements to the two melting processes are still not fully understood in granite petrogenesis. To address this, we conducted trace element modelling of open system melting using phase equilibrium calculations combined with solubility equations for accessory minerals and mineral–melt partition coefficients based on three melt-reintegrated felsic granulite compositions. The results indicate systematic differences between the compositions of disequilibrium (Type I) and equilibrium (Type II) melts involving water-present melting reaction, fluid-absent melting reaction involving biotite, and fluid-absent melting reaction in the absence of biotite. Type I melts generally have higher Rb, Ba, Co, Ni, V, and Cr contents, and Rb/Sr and Nb/Ta ratios, and lower Sr, P, Th, U, and light rare earth element contents than Type II melts. Significantly, disequilibrium melting involving biotite can produce melts with high Nb contents and super-chondritic Nb/Ta ratios, which may be a reservoir for the missing Nb on Earth. Compared with Type II melts, the trace element contents and ratios of Type I melts exhibit a larger range, more complex trends, and are more sensitive to changes in melting reaction types and melt loss. This suggests that, in addition to petrogenetic processes such as crystal entrainment, fractional crystallization and magma mixing, the disequilibrium melting would also contribute to the compositional diversity of granites. The modelling results also show that the trace element signatures of granites that are commonly used to determine their petrogenetic processes and tectonic setting may lead to erroneous conclusions if the granitic melts were produced by disequilibrium melting.

Analysis of the Elemental Composition of Gonads, Gametes and Larvae of the Mussel &lt;i&gt;Mytilus galloprovincialis&lt;/i&gt; in the Spawning Period

In this work, we studied the elemental composition of gonads, eggs, sperm and larvae of the mussel Mytilus galloprovincialis during spawning, when the contents of biologically active compounds and minerals are maximal. A comparative analysis of the contents showed that the elements are involved in the mussel gametogenesis in different pathways. There were significant differences in the contents of Li, B, Mg, Si, P, K, Ca, V, Cr, Mn, Fe, Co, Ni, Zn, Ge, As, Se, Br, Rb, Sr, Mo, Pd, Sn, I, Ba and Ce in male and female gonads before and after spawning, gametes and larvae of mussels. It is likely that some of the listed elements are not only passively accumulated in the mollusk body, but are also essential, being directly involved in the reproduction process. Most of significant differences in the element contents were found between eggs and larvae and between male gonads before spawning and sperm. By spawning, mussel gonads accumulated mainly p- and d-elements, apparently due to the ability of their ions to form complexes and, consequently, to be included in the structure of enzymes. The contents of B, Mg, Si, P, K, Ca, Cr, Mn, Fe, Cu, Zn, As, Se, Br, Sr and Ba in male and female gonads, gametes and larvae were an order or several orders of magnitude higher than those of other elements. The contents of Ca, Fe, Sr, Sn and I in mussel larvae were significantly higher than in gonads and gametes. Sn is a technological hydropollutant, and thus, larvae can serve as a bioindicator of the aquatic environment pollution with this element. The data obtained are of practical interest for improving the biotechnology of reproduction of marine hydrobionts and obtaining functional products based on them, which is important for the optimization of aquaculture management and for addressing human health-related issues.

Optimization of technical and technological indicators of kefir added with defatted sesame flour and rice bran

Defatted sesame cake and rice bran are all by-products of agricultural processing. The aim of the study was to optimize the recipes of kefir added with defatted sesame flour and rice bran. The previous study has yielded some results including dietary fiber content, pH values and sensory evaluation values of kefir samples added with 0, 2 %, 4 %, 6 %, 8 % DSC and 0, 0.1 %, 0.3 %, 0.5 %, 0.7 % RB, but made no optimization of kefir products. Based on these data, formulation optimization was done using a mathematical model. Two central composite designs for the two-factor analysis (x1x2 and x1x3, respectively) and one three-factor design (x1x2x3) were drawn up to predict the optimal formulation and reduce the number of future experiments. After studying the results of mathematical modeling, the optimal prescription composition corresponds to the 2 % DSC or 0.1 % rice bran content or 2 % DSC and 0.4 % RB content in the recipe. Through mathematical optimization, products with high dietary fiber content, suitable acidity and excellent sensory quality can be obtained. The products meet the current social demand for healthy food and have very good research value. In practical use, three kinds of kefir can be developed: 1. DSC should be ground separately before used, 2 % DSC was introduced into cow milk (m/v), fermented at 28°C for 22 h until pH reached 4.7, then stored at 4 °C; 2. RB should be ground before used, 0.4 % RB was introduced into cow milk (m/v), fermented at 28°C for 22 h until pH reached 4.7, then stored at 4°C; 3. DSC and RB should be ground before used, 2 % DSC and 0.4 % RB were introduced into cow milk (m/v), fermented at 28 °C for 22 h until pH reached 4.7, then stored at 4 °C

Geochemistry of a paleo-oxbow lake sediments and its implications for the late Holocene extreme overbank flooding history of the Yellow River within the Zoige Basin, NE Tibetan Plateau

Paleo-oxbow lake sediments can provide archives to reconstruct paleo-channel evolution and flooding history of the river. Multi-proxy approaches including detailed sediment stratigraphy, sedimentology and geochemistry have been implemented in a high-resolution sedimentary section of paleo-oxbow lake of the Yellow River within the Zoige Basin on the NE Tibetan Plateau, to reconstruct regional environmental changes and extreme overbank flooding history. Our results suggest that not only traditional sedimentological proxies, but also chemical elements can be applied in defining sequences with different genetic types, especially the paleoflood deposits in the paleo-oxbow profile. Two units of late-Holocence extreme overbank flooding deposits (OFDs) are identified in terms of the significantly higher proportions of sand, high contents of SiO2, Na2O, Ba, low contents of Al2O3, Fe2O3, MgO, K2O, Ti, Rb and high values of Zr/Fe, Zr/Rb ratios. These extraordinary flood events within the Zoige Basin were dated back to 2,960 ± 240–2,870 ± 270 a and 1840 ± 200–1700 ± 160 a, in response to the mid-Holocene climatic optimum to the late Holocene and the Dark Age Cold Period (DACP). And the strong rainfall caused by the abnormal atmospheric circulation during the period of climate transition and abrupt change may led to the frequent occurrence of extreme flood events in the source region of the Yellow River. These findings are important for understanding the response of regional fluvial system to high climatic instability and provide a new perspective for us to analyze the risk of flood disasters on the Tibetan Plateau under the background of climate change.

The behavior of separation and enrichment of valuable metals during the synergistic processing of metallurgical dust and sludge via roasting in rotary kiln

The generation of ironmaking and steelmaking dust and sludge exceeds 100 million tons annually, and stacking critically pollutes the environment. The joint treatment of such wastes for recycling metals is a promising approach to resolving these problems. This study focused on the separation and enrichment of metals during the synergistic processing of blast furnace dust, electric arc furnace dust, and steel pickling sludge in a rotary kiln at high temperature. Research results indicate that Na2O, K2O, Rb2O, Cu2O, ZnO, CdO, PbO, Bi2O3, and Sb2O3 may be separated during roasting. Under optimized Zn removal conditions of 30 min roasting time and 1373 K roasting temperature, the removal percentages of Sn, Sb and Cu reach 91.9%, 97.2%, and 72.4%, respectively, while Bi, Rb and Cd are removed almost entirely from the mixture of dust and sludge. The removed metals condense before the flue gas outlet (330 K) and are concentrated in the Zn-rich powder. The concentrations of Sn, Sb, Bi, Rb, and Cd in the Zn-rich powder were 5–7 times those in the mixture. The synergistic treatment of metallurgical dust and sludge may facilitate the efficient separation and enrichment of certain valuable metals, and the methods may be extended to jointly processing the other solid wastes; however, HCl gas formation may complicate gas cleaning.

Formation and evolution of multistage hydrothermal fluids in the Baishitouwa quartz–wolframite vein‐type deposit in the southern Great Xing'an Range tungsten belt, NE China: Constraints from individual fluid inclusion LA‐ICP‐MS analysis

Revealing hydrothermal evolution from the early oxide to late carbonate stages for quartz–wolframite vein‐type deposits is essential for understanding the ore‐forming process. In this study, we choose the Baishitouwa tungsten polymetallic deposit located in the southern Great Xing'an Range tungsten belt as a case study, and present detailed deposit geology and in situ fluid inclusion (FI) analyses including microthermometry, laser Raman spectra, and LA‐ICP‐MS microanalysis to address this issue. Four stages of hydrothermal activity were identified: (1) quartz–wolframite (I), (2) quartz–wolframite (II)–pyrite–chalcopyrite, (3) quartz–polymetallic sulphides, and (4) quartz–carbonate. Four types of FIs were recognized: CO2‐rich, CO2‐bearing, liquid‐rich, and brine inclusions. Microthermometric data showed that the homogenization temperatures and salinities from the early to late stages are 380–460°C, 7.4–17.3, and 29.3–43.2 wt% NaCl equiv., 300–390°C and 7.1–17.0 wt% NaCl equiv., 220–320°C and 2.7–8.1 wt% NaCl equiv., and 150–250°C and 0.5–4.8 wt% NaCl equiv., respectively, suggesting a decreasing trend. Geochemically, all stage fluids contained high Rb and Mn concentrations, high Rb/Na, Cs/Na, Li/Na, K/Na, Rb/Sr, low K/Rb, and consistent Cs/Rb and Cs/(Na + K) ratios, indicating that the mineralizing fluids originated from a common source—an underlying, geochemically uniform, and highly fractionated granitic magma. Fluid immiscibility and cooling are the main mechanisms for wolframite precipitation, whereas greisenization is subordinate; the incursion of meteoric water into the hydrothermal system initiated at the sulphide stage, and fluid mixing is the dominant mechanism for sulphide precipitation.

MAGMA COMPOSITION AND FORMATION CONDITIONS OF ALKALI-SALIC ROCKS OF THE EARLY MESOZOIC ADAATSAG BIMODAL ASSOCIATION OF THE KHARKHORIN RIFT ZONE OF CENTRAL ASIA (DATA FROM THE STUDY OF MELT INCLUSIONS IN MINERALS)

Based on the method of investigation of melt inclusions using electron and ion microprobe, the magma composition and formation conditions of comendites of the Early Mesozoic Adaatsag volcanic association (Mongolia) were studied. The mechanisms leading to the accumulation of rare and rare earth elements in them were determined. Melt and fluid inclusions are found in quartz from the comendites, collected from different parts of the volcanic sequence. The melt inclusions consist of glass, a gas bubble and daughter minerals represented by fluorite, polylithionite and potassium feldspar. The use of the Raman spectroscopy method made it possible to study the composition of the gas phase in melt inclusions. It is determined that the predominant components of the gas phase are water and hydrogen. Fluid inclusions are represented by aqueous solutions that correspond to KF in composition. The concentration of KF in the solution reach up to 4.0–4.1 wt. %. Thermometric experiments with melt inclusions and analysis of the composition of glasses of homogenized melt inclusions in quartz of the comendites showed that the crystallization of magmas of these rocks occurred from water-saturated rare-metal melts with high contents of Li, Zr, F, Rb, Nb, Y and Th at temperatures of 880–930°C and at a pressure of 1000 bar at a depth of ~3.5 km and was accompanied by degassing processes. Comparison of the obtained data on the study of melt inclusions in the phenocrysts of the alkali-salic rocks of the same age volcanic associations Adaatsag, Dzarta-Кhuduk and Sant, developed within the Kharkhorin rift zone, revealed general patterns of their magma evolution. This allowed us to propose a similar mechanism of their formation, involving the accumulation of many rare and rare-earth elements, as well as volatile components (F, H2O) in the process of crystallization differentiation. Subsequently, a salt melt rich in Li, F and water could be separated from such comendite magmas. The detection of fluoride aqueous inclusions in quartz allows us to suppose the further evolution of the salt melt leading to the appearance of a concentrated aqueous fluid and the possible participation of the latter in metasomatic processes.

Wildland-urban interface fire ashes as a major source of incidental nanomaterials.

Although metal and metalloid concentrations in wildfire ashes have been documented, the nature and concentrations of incidental nanomaterials (INMs) in wildland-urban interface (WUI) fire ashes have received considerably less attention. In this study, the total metal and metalloid concentrations of 57 vegetation, structural, and vehicle ashes and underlying soils collected at the WUI following the 2020 fire season in northern California - North Complex Fire and LNU Lightning Complex Fire - were determined using inductively coupled plasma-time of flight-mass spectrometry after microwave-assisted acid digestion. The concentrations of Ti, Zn, Cu, Ni, Pb, Sn, Sb, Co, Bi, Cr, Ba, As, Rb, and W are generally higher in structural/vehicle-derived ashes than in vegetation-derived ashes and soils. The concentrations of Ca, Sr, Rb, and Ag increased with increased combustion completeness (e.g., black ash < gray ash < white ash), whereas those of C, N, Zn, Pb, and In decreased with increased combustion completeness. The concentration of anthropogenic Ti - determined by mass balance calculations and shifts in Ti/Nb above the natural background ratios - was highest in vehicle ash (median: 30.8gkg-1, range: 4.5-41.0gkg-1) followed by structural ash (median: 5.5 gkg-1, range: of 0-77.4gkg-1). Various types of carbonaceous INM (e.g., amorphous carbon, turbostratic-like carbon, and carbon associated with zinc oxides) and metal-bearing INMs (e.g., Ti, Cu, Fe, Zn, Mn, Pb, and Cr) with sizes between few nanometers to few hundreds of nanometers were evidenced in ashes using transmission electron microscopy, including energy dispersive X-ray spectroscopy. Overall, this study demonstrates the abundance of a variety of metals and metalloids in the form of INMs in WUI fire ashes. This study also highlights the need for further research into the formation, transformation, reactivity, fate, and effects of INMs during and following fires at the WUI.