Rb Concentrations Research Articles

Source controls on mineralisation: Regional geology and magmatic evolution of Fiji

There is a well-established link between world-class gold telluride mineral deposits and alkalic magmatic host rocks, often emplaced post-subduction in arc terranes. Fiji is home to two such deposits, and provides an ideal location to study the relationship between the alkalic (shoshonitic) host rocks, their geodynamic context, and potential roles in metal enrichment. A total of 93 new geochemical analyses of magmatic rocks from across Fiji are presented, alongside detailed petrography and mineralogy and a new compilation of literature data. Despite relatively similar mineralogy across syn- and post-subduction samples, there are geochemical differences between them, with the latter displaying elevated concentrations of Ba (<2137 ppm), Rb (<218 ppm), Sr (<2648 ppm) and K2O (<10.18 wt%), and depletions in Nb and Ta. Multi-element trends suggest exaggerations of ‘typical’ arc patterns in post-subduction shoshonites. Geochemical data suggest that whilst the fluxing of fluids and sediment melts from a subducted slab may play a role in producing the distinctive post-subduction magmas, they are likely insufficient to drive such strong trends. Instead, biotite or possibly phlogopite in the lithosphere are suggested as being a key ‘ingredient’. Earlier subduction can modify the lithosphere through the addition of hydrous phases, both by metasomatism of the lithospheric mantle, or by the formation of residual minerals during fractional crystallisation. Remelting of these phases could liberate trace elements and metals. Biotite in particular could facilitate some of the observed large ion lithophile elements (LILE) enrichments and the alkali-rich (potassic) nature of the magmas.

Age dependence of iodine to some trace element content ratios in normal thyroid of females investigated by neutron activation and inductively coupled plasma mass spectrometry

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 (TE) contents in thyroid play important role in goitro- and carcinogenesis of gland. The correlations between age and thirty-eight TE, including I, as well as between age and I/TE content ratios in normal thyroid of 33 females (age range 3.5-87 years) was investigated by two methods: instrumental neutron activation analysis and inductively coupled plasma mass spectrometry. Our data reveal that the Co, Cs, La, Pb, Rb, Sb, Se, Sn, Tl, and Zn contents increase, while I/Cd, I/Ce, I/Cs, I/La, I/Li, I/Mo, I/Nd, I/Pb, I/Pr, I/Sn, I/Tl, I/Zn content ratios decrease in the normal thyroid of female during a lifespan. Therefore, a goitrogenic and tumorogenic effect of excessive Co, Cs, La, Pb, Rb, Sb, Se, Sn, Tl, and Zn level in the thyroid of old females, as well as a disturbance in intrathyroidal I/Cd, I/Ce, I/Cs, I/La, I/Li, I/Mo, I/Nd, I/Pb, I/Pr, I/Sn, I/Tl, I/Zn relationships with increasing age may be assumed.

Geochemical and Cathodoluminescence Properties as Discriminators to Characterize K-Feldspar in Different Genetic Settings

ABSTRACTPotassic alteration is a common feature in hydrothermal ore systems, and both its occurrence and degree can be important features applicable to ore deposit exploration. Here we report results from optical cathodoluminescence (CL) and chemical composition investigations on K-feldspar of different origins in and around the Early Cretaceous lode gold deposits in the Xiaoqinling area, located along the southern margin of the North China Craton.We focus on K-feldspars from an Early Cretaceous biotite monzogranite (G-Kfs), a Paleoproterozoic migmatite (M-Kfs), and a hydrothermal alteration zone of Early Cretaceous gold deposits (H-Kfs). The grain size of G-Kfs ranges from 1 to 4 mm, usually exhibits tartan twinning, and occasionally shows evidence of exsolution. Part of the M-Kfs exhibits tartan twinning, and the grain size shows wide variation (from tens of microns to several centimeters), while the H-Kfs shows no twinning, and the grain size is generally less than 0.5 mm.Optical CL analyses show that the G-Kfs exhibits two emission bands at around 466–472 and 708–713 nm which occur in multiple, alternating dark red and blue zones. The M-Kfs exhibits blue, red, and/or violet-red luminescence resulting from two emission bands at 446–465 and 694–701 nm. The H-Kfs displays a distinct greenish-yellow luminescence resulting from an emission band at 545–550 nm.Electron probe microanalyses show that among the three K-feldspar types, the G-Kfs contains higher Na2O (average: 0.71 wt.%) and Al2O3 (average: 18.79 wt.%) and lower K2O (average: 15.62 wt.%), whereas the H-Kfs shows higher K2O (average: 16.31 wt.%) and lower Na2O (average: 0.45 wt.%) and Al2O3 (average: 18.61 wt.%). The K2O, Na2O, and Al2O3 contents of the M-Kfs are intermediate between those of the G-Kfs and H-Kfs. In transitioning from the G-Kfs, M-Kfs, to H-Kfs, it is noted that the concentrations of Sr, Ba, and Pb decrease progressively, whereas W, V, Zn, Mn, Sc, Ge, and Ga gradually increase. Concentrations of La, Ce, and Eu in the H-Kfs are lower than in the G-Kfs and M-Kfs, and the Cr and Cu concentrations in the G-Kfs are the lowest. Scatter diagrams constructed with Sr, Ba, Pb, and Rb concentrations show that the three types of K-feldspars fall into different fields. These, as well as the CL and spectral properties of K-feldspar, can clearly distinguish the K-feldspars of magmatic, metamorphic, and hydrothermal origin in the study area.

Relationship between Trace Elements Levels and Lung Cancer Patients in Southern Iraq

Background: Our life relies on our ability to use all sorts of materials, like trace elements, in the world for our needs. The using of heavy metals has greatly contributed to the comfort of our everyday lives. Blood is directly affected by poisoning when such metals are inhaled from environments where heavy metals occur in high levels. Research is constantly advancing our knowledge of the connection between various trace elements and disease, particularly cancer, since the effects of heavy metals on human health remain a serious health concern.&#x0D; Objective: The objective of this work is to establish levels of a range of elements in human blood, serum and hair samples of patient undergo lung cancer comparing with control (healthy persons) so that potential exposures can be better identified in future cases.&#x0D; Methods: Elements concentrations including As(arsenic), Ba(barium), Co(cobalt), Li(lithium), Mg(magnesium), Mn(manganese), Mo(molybdenum), Rb(rubidium), Sr(strontium) and Ti(titanium) was analysis used MS ICP (an inductively coupled plasma atomic absorption spectrophotometer).&#x0D; Results: Test found that Mn has substantially (p&lt;0.05) high concentration in three tissues including whole blood, serum, and hair of patients with lung cancer (291,487.2,68.03) ug / l respectively. In comparison as occurs in the lowest concentration. Sr was 77.5ug / l, Rb 41.6ug / l, and Ba 35.2ug / g. On other hand, Co, Li, Mg, Mo and Ti were found in low levels ranged 1.7-5.5 ug/l, in whole blood of patients. Hair samples accumulated the lowest concentration of As, Ba, Co, Mg, Mn and Rb. When we compare the concentration of trace elements between lung patients and control samples, that clear most of the elements accumulate at high levels in lung cancer patients. Result found significantly high As, Ba, Co, Mg, Mo concentration in whole blood and serum of lung cancer patients, in contract, Li, Mn and Rb occur in high levels in whole blood of control sample. Even as hair of control samples have elevated levels of As, Sr and Ti. However, concentrations of trace elements in the whole blood of smokers and non-smokers showed that all ten elements accumulated at elevated levels in the blood of smokers relative to non-smokers. Spearman correlation found significantly positive correlation among trace elements in the blood of patients with smoker lung cancer and non-smokers.&#x0D; Conclusion: The study conclude that trace metals level in smokers persons are elevated than non-smokers. The findings of this study lend some support to the link between heavy metals pollution and lung cancer cases.

Ore genesis of the Narenwula quartz-vein type W polymetallic deposit in the southern Great Xing’an Range W belt, NE China: Constraints from wolframite geochronology and individual fluid inclusion analysis

The Narenwula deposit, situated in the southern Great Xing’an Range W belt, is a large-scale quartz-vein type W polymetallic deposit in NE China. The mineralization is spatially associated with Late Jurassic monzogranite and granite porphyry. In this study, we present detailed description of the ore geology, wolframite in-situ U-Pb dating, and fluid inclusion analyses including microthermometry, laser Raman spectra, and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) microanalyses to precisely constrain the timing of ore formation, origin and evolution of ore-forming fluids as well as metal precipitation mechanisms. In-situ U-Pb dating of hydrothermal wolframite yields a W mineralization age of 136.4 ± 2.0 Ma (1σ, MSWD = 1.3), which is ∼14 Ma younger than the zircon U-Pb ages of W-bearing granitoids, indicating the W-bearing granitoids are not genetically related to the W mineralization at Narenwula. The hydrothermal process can be divided into four stages: stage I is characterized by abundant wolframite (I), which is the dominant stage of W mineralization; stage II is featured with the development of wolframite (II) together with minor amounts of pyrite and chalcopyrite; stage III is the predominant stage of sulfide mineralization; and stage Ⅳ is characterized by lack of sulfide or wolframite and occurrence of quartz, carbonate, and fluorite. Cathodoluminescence analysis of quartz further revealed four generations of quartz, corresponding to the four hydrothermal stages. Four types of fluid inclusions were distinguished for quartz, including CO2-rich (C1-type), CO2-bearing (C2-type), liquid-rich (l-type), and brine (B-type) fluid inclusions. Fluid inclusion microthermometry shows a decrease in homogenization temperatures and salinities from the early to late stages. The ranges of the homogenization temperature for stages I to Ⅳ are 440–280, 320–240, 260–180, and 200–160 ℃, respectively, and the ranges of salinities for stages II to Ⅳ are 2.9–17.8, 1.4–10.2, and 0.4–6.7 wt% NaCl equiv., respectively. The salinities of fluid inclusions from stage I have a bimodal distribution in the ranges of 9.6–17.4 and 31.1–35.6 wt% NaCl equiv. Individual fluid inclusion LA-ICP-MS analyses suggest a magmatic source for the fluids of all stages, evidenced by the high Rb and Mn concentrations, high Rb/Na, K/Na, Cs/Na, Li/Na, and Zn/Na ratios, which are distinctly different from those of basinal brines. The Rb/Sr and K/Rb ratios of fluid inclusions are similar to those of Late Mesozoic highly fractionated W-mineralized granitoids in NE China, indicating that the metallogenic parent rocks at Narenwula are highly evolved. In combination with evidence of consistent Cs/Rb and Cs/(Na + K) ratios of fluid inclusions from all stages, we suggest that the mineralizing fluids originated from an underlying, geochemically uniform, and highly fractionated granitic magma. Fluid immiscibility and fluid-rock interaction (especially greisenization) are the main mechanisms for wolframite precipitation, whereas natural cooling of fluids may be subordinate. Fluid inclusion data provide evidence that the addition of meteoric water to the magmatic-hydrothermal fluid initiated at the sulfide mineralization stage, and the fluid dilution and cooling due to fluid mixing played an important role in the process of sulfide precipitation. This study highlights that W and base metals (e.g., Cu, Pb, Zn) in ore-forming fluids display different migration and precipitation progresses, the knowledge of which is important for elucidating multi-stage ore-forming processes of quartz-vein type W polymetallic deposits in NE China.

Determination of concentrations of non-volatile elements in fly ash released from coal combustion using EDXRF

ABSTRACT In this study, the concentration of thirteen non-volatile elements in coal fly ash samples obtained from the Kangal coal-fired thermal power plant located in Sivas province of Turkey was determined using an energy dispersive X-ray fluorescence (EDXRF) spectrometer. Non-volatile elements in coal fly ash samples were analysed in three groups: major (Al, Si, and Ca), rare earth (Y, La, Ce, Pr, and Nd), and other trace elements (Ga, Rb, Mo, Ba, and Hf). The average concentrations of Ca, Si and Al were found as 22.8, 10.9 and 5.4%, respectively. The average concentrations of Pr, Y and, Nd were found as 23.9, 19.1 and 78.2, respectively. La and Ce were observed below the detection limit of 2 mg/kg, except for two samples. The average concentrations of Ga, Rb, Mo, Ba and Hf were found as 18.6, 51.1, 177.3, 993.5 and 3.9 mg/kg, respectively. According to the average values of enrichment factor estimated for elements analysed in fly ash samples, Mo is found extremely enriched while Ca and Hf are significantly enriched.

Textural and chemical characteristics of beryl from the Baishawo Be-Li-Nb-Ta pegmatite deposit, Jiangnan Orogen: Implication for rare metal pegmatite genesis

The Baishawo pegmatite deposit is a newly discovered large Be-Li-Nb-Ta deposit, with estimated reserves of 16,160 t BeO @ 0.084 %, 11,280 t Li2O @ 0.85 %, and 3,450 t (Ta2O5 + Nb2O5) @ 0.201 %. The 3# pegmatite is internally zoned into border (contact against two-mica granite), wall, intermediate, and core zones. Beryl, the dominant economic mineral, occurs mainly in the intermediate and wall zones. In the intermediate zone, beryl coexists with feldspar and quartz, and in the wall zone, with quartz, tourmaline, garnet, and feldspar. Geological and petrographic observation, Electron-probe Microanalysis (EPMA), TESCAN Integrated Mineral Analyzer (TIMA), X-ray mapping, and Laser Ablation Inductive Coupled Plasma Mass Spectrometry (LA-ICP-MS) analysis were conducted to study the textural and compositional features of the beryl. The EPMA data show the concentrations of Al2O3, SiO2 and BeO in beryl are 17.61–18.32 wt.%, 64.01–65.23 wt.%, and 13.09–13.89 wt.% from the intermediate zone, respectively, and 17.57–18.52 wt.%, 64.33–65.15 wt.%, and 13.20–14.10 wt.% from the wall zone, respectively. Beryl from the intermediate zone contains higher concentrations of Ti (4.29–34.5 ppm), Mn (33.9–277 ppm), Rb (86.2–230 ppm), Cs (3333–4522 ppm) and Sn (0.571–28.7 ppm) than beryl from the wall zone (Ti 2.65–5.70 ppm, Mn 19.0–54.2 ppm, Rb 104–114 ppm, Cs 747–1242 ppm and Sn 0.085–1.26 ppm). Substitutions in beryl of the intermediate and wall zones are Li for Be, and Fe for Al. The distributions of alkali metals, Mg and Fe in beryl suggest that the pegmatite in the two beryl-bearing zones is the product of magmatic-hydrothermal interaction. Decreasing Mg content and Mg/Fe ratio with increasing Cs content and Cs/Na ratio suggest that beryl compositions reflect evolution of a highly differentiated two-mica granite magma, of which there is a residual fraction.

Macro Minerals and Trace Elements in Milk of Dairy Buffaloes and Cows Reared in Mediterranean Areas

Aim of this study was to evaluate the differences in Ca, P, K, Na, Mg, Zn, Fe, Cu, Mn, Se, Mo, Co, Li, B, Ti, Rb, and Sr concentrations in milk from buffaloes and cows reared in the same farm in Mediterranean areas and fed diets including the same ingredients. Individual milk samples were obtained from 32 Mediterranean buffaloes and 29 Italian Friesian cows and samples of milk, dietary ingredients and drinking water were analyzed for the investigated chemical elements by inductively coupled plasma-mass spectrometry. Data about milk element concentrations were processed by one-way analysis of variance. Buffalo milk contains higher concentrations of Ca, P, Mg, Zn, Fe, Cu, B, Ti, and Sr, and lower concentrations of K, Na, Mo, Li, and Rb compared to cow milk, whereas milk from both species contains similar concentrations of Mn, Se, and Co. The concentrations of the investigated elements in the diet were similar for both species and the differences observed between buffalo and cow milk were not dependent on environmental factors.

The cell cycle inhibitor RB is diluted in G1 and contributes to controlling cell size in the mouse liver.

Every type of cell in an animal maintains a specific size, which likely contributes to its ability to perform its physiological functions. While some cell size control mechanisms are beginning to be elucidated through studies of cultured cells, it is unclear if and how such mechanisms control cell size in an animal. For example, it was recently shown that RB, the retinoblastoma protein, was diluted by cell growth in G1 to promote size-dependence of the G1/S transition. However, it remains unclear to what extent the RB-dilution mechanism controls cell size in an animal. We therefore examined the contribution of RB-dilution to cell size control in the mouse liver. Consistent with the RB-dilution model, genetic perturbations decreasing RB protein concentrations through inducible shRNA expression or through liver-specific Rb1 knockout reduced hepatocyte size, while perturbations increasing RB protein concentrations in an Fah −/− mouse model increased hepatocyte size. Moreover, RB concentration reflects cell size in G1 as it is lower in larger G1 hepatocytes. In contrast, concentrations of the cell cycle activators Cyclin D1 and E2f1 were relatively constant. Lastly, loss of Rb1 weakened cell size control, i.e., reduced the inverse correlation between how much cells grew in G1 and how large they were at birth. Taken together, our results show that an RB-dilution mechanism contributes to cell size control in the mouse liver by linking cell growth to the G1/S transition.

Reconciling the geogenic and non-crustal origins of elements in an Indo-Bangla transboundary river, Atrai: Pollution status, sediment quality, and preliminary risk assessment

This study has been conducted on an anthropogenically less influenced transboundary river (Atrai: Indo-Bangladesh) to comprehend the inherent geochemistry and identify potential elemental sources. In doing so, across the Bangladeshi portion, 30 river-bed samples were culled and studied by neutron activation analysis to quantify the abundances of 15 geochemically and toxicologically significant elementals (Na, Al, K, Ti, Cr, Mn, Co, Zn, As, Rb, Sb, Cs, Ba, Th, and U). The results revealed that the mean concentrations (μg/g) of Rb (154.6), Cs (7.53), Th (20.90), and U (4.88) were 1.5–2.0 times higher than crustal values. Besides, geo-environmental indices revealed ‘uncontaminated to moderately contaminated’ pollution status with minor enrichment or contamination for Rb, Th, Sb, U, and Cs, relatively concentrated in the mid-to-downstream zone possessed geogenic and non-crustal origins. The positive matrix factorization and other statistical approaches revealed predominant geogenic enrichment of Na, K, Al, Ti, Zn, Cs, Rb, As, Th, and U from differential mineralogical compositions via weathering, elemental fractionations, and biogeochemical mobilization. Contrariwise, several anthropogenic sources (for Cr, Sb, Co, Mn, Th) were also ascertained in the vicinity of Atari River. However, sediment characterization based on SQG threshold values manifested that Cr and Mn possess rare biological effects on local aquatic organisms. Nevertheless, SQGs-based and ecological risk indices invoked minor to no potential ecotoxicological intimidations for the considered metal(oid)s (Cr, Mn, Co, Zn, As, and Sb). Hence, this study manifested the usefulness of a less anthropogenically affected river to reckon geogenic and non-crustal elemental origins in the compounded riverine sediment.

Geochemical expression of sequence stratigraphic surfaces: A case from Upper Cretaceous shallow-water carbonates of southeastern Neo-Tethys margin, SW Iran

Providing a chronostratigraphic framework often is problematic in shallow-marine carbonates with poor biostratigraphic resolution. In such cases, an integration of geochemical, sedimentological, and paleontological data can be used to construct a reliable sequence stratigraphic framework. This study focuses on elemental concentrations and isotopic ratios of Cenomanian–Santonian (C–S) neritic carbonates in SW Iran used to construct a sequence stratigraphic framework, asses sequence ages and durations of hiatus. The diagenetic and geochemical expression of two paleoexposure surfaces, representing type-I sequence boundaries (SBs), are discussed. Increase in Fe and Rb concentrations and decrease in Ca content are recorded at and/or below distinct erosional surfaces. Mg content shows a facies-dependent response with former LMC (low magnesium calcite) or aragonitic facies showing increase while HMC (high magnesium calcite) indicates decrease in response to SBs. Mn shows considerable changes apart from sequence surfaces that are strongly facies dependent. Sr concentrations show an increase in HMC and decrease in LMC in samples which experienced semi-closed meteoric diagenesis, far below the SBs. However, in samples characterized by open system diagenesis, directly underlying the SBs, Sr tends to decrease in all components. The Sr/Rb ratio is a reliable tool in detecting erosional SBs, shown as conspicuous negative excursions. C (carbon) and O (oxygen) isotopes show distinct negative excursions at erosional SBs and a slight increase at or around the MFSs. The 87Sr/86Sr ratio shows clear positive excursions at SBs probably due to 87Rb decay in incorporated aluminosilicate detritus, which makes it as the most reliable proxy for the detection of SBs in the studied sections. Two main erosional SBs are marked by 87Sr/86Sr ratios including the CT-ES (Cenomanian–Turonian boundary exposure surface) and mT-ES (middle Turonian exposure surface) with hiatus durations of 0.53 and 2.7 Myr, respectively. These paleoexposure surfaces are correlated with other neritic sections of C–S sequences in SW Iran.

First record of trace element accumulation in a freshwater ectoparasite, Paradiplozoon ichthyoxanthon (Monogenea; Diplozoidae), infecting the gills of two yellowfish species, Labeobarbus aeneus and Labeobarbus kimberleyensis

BackgroundElevated levels of trace elements in the aquatic environment poses risks to the health of biota and humans. Parasites are important components in ecosystems; responding to changes in the health of aquatic ecosystems and can accumulate trace elements in their tissues to higher levels than their hosts. Monogeneans are an important group of fish ectoparasites being directly exposed to the aquatic environment. MethodsIn this study concentrations of Ti, Fe, Cu, Zn, Rb, Sr and Ag were analysed in the monogenean parasite, Paradiplozoon ichthyoxanthon (by total reflection x-ray fluorescence spectrometry and graphite furnace atomic absorption spectrometry), and the muscle, liver and gills of two host fish species, Labeobarbus aeneus and Labeobarbus kimberleyensis (by inductively coupled plasma -– mass spectrometry). ResultsMost striking was the accumulation pattern for Zn in parasites; mean levels of Zn were as high as 1448 and 1652 mg kg−1 dw, respectively, with no significant difference between the two host-parasite groups, leading to bioconcentration factors of approximately 93 (parasite/fish muscle) and 15 (parasite/fish liver). In addition, Fe was accumulated in the parasite to a higher degree compared to the fish hosts’ tissues. Cu levels were higher in P. ichthyoxanthon than in the muscle tissue of both host fishes, but lower than liver tissue. ConclusionThese findings demonstrate the usefulness of this parasite species as a sentinel organism in aquatic ecosystems it inhabits for Fe and Zn. Other trace elements under investigation were not accumulated higher in the parasite compared to its fish host. Lower Rb levels in the parasite compared to its hosts indicate no biomagnification of this metal. Further investigations are required to determine if similar trends in trace element accumulation occur in other monogeneans. Data availabilityAll data generated in the analysis of host and parasite tissues are presented in the manuscript.

Geochemistry of beryl varieties: comparative analysis and visualization of analytical data by principal component analysis (PCA) and t-distributed stochastic neighbor embedding (t-SNE)

A study of the trace element composition of beryl varieties (469 SIMS analyses) was carried out. Red beryls are distinguished by a higher content of Ni, Sc, Mn, Fe, Ti, Cs, Rb, K, and B and lower content of Na and water. Pink beryls are characterized by a higher content of Cs, Rb, Na, Li, Cl, and water with lower content of Mg and Fe. Green beryls are defined by the increased content of Cr, V, Mg, Na, and water with reduced Cs. A feature of yellow beryls is the reduced content of Mg, Cs, Rb, K, Na, Li, and Cl. Beryls of various shades of blue and dark blue (aquamarines) are characterized by higher Fe content and lower Cs and Rb content. For white beryls, increased content of Na and Li has been established. Principal Component Analysis (PCA) for the CLR-transformed dataset showed that the first component separates green beryls from other varieties. The second component divides pink and red beryls. The stochastic neighborhood embedding method with t-distribution (t-SNE) with CLR-transformed data demonstrated the contrasting compositions of green beryls relative to other varieties. Red and pink beryls form the most compact clusters.

In utero deposition of trace elements and metals in tissues

IntroductionAll animals, including humans, are exposed to heavy metals which are known to accumulate in different tissues, especially in bone. During pregnancy, the maternal bone turnover is increased and the metals in the mother’s body can be mobilized into the bloodstream. Heavy metals in maternal blood are known to pass through the placenta to the fetal blood and finally, deposited to bone tissue. However, there are no studies on the concentration of metals in the fetal solid tissues and until now, the rate of metal transfer from mother to fetus is not exactly known. Materials and methodsSamples of the blood, liver, placenta, and three different bones were collected from 17 pregnant ewes and their 27 fetuses. The animals had no known exposure to heavy metals. The concentrations of Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Mo, Na, Ni, P, Pb, Rb, Sb, Sn, Sr, Te, Ti, Tl, V, and Zn were analyzed using ICP-MS. Results and discussionThe concentration of Sb, Sn, Te, and Tl were under the detection limit in all the samples. The other metals were found in all maternal and fetal tissues, suggesting that all detectable metals cross the placenta. Blood concentrations were low compared to solid tissue concentrations. The concentrations of essential elements varied between maternal and fetal tissues, which could be explained by biological differences. The differences in concentrations of non-essential elements between the ewe and fetuses were smaller. The most significant differences were between maternal and fetal concentrations of Ba and Sr, which is at least partly explained by the mineralization degree of the bone. ConclusionHeavy metals accumulate in fetal solid tissues in sheep that are not directly exposed to heavy metals. Because of the differences in anatomy between human and sheep placenta, the accumulation in the tissue of human fetuses should be extrapolated cautiously. However, there might be some clinical relevance for fertile aged women who are exposed to heavy metals, such as women who work in the metal industry or who have undergone joint replacement surgery.

Efficiency of metal bioaccumulation in acanthocephalans, gammarids and fish in relation to metal exposure conditions in a karst freshwater ecosystem

BackgroundEach of the bioindicator organisms studied, such as fish, crustaceans, or parasites, have certain advantages when used in the assessment of metal exposure. In this research, special attention was given to intestinal parasites, acanthocephalans, as effective metal bioaccumulators with the main aim of estimating and comparing metal accumulation in all organisms involved in their life cycle and testing their usage as sensitive bioindicators in metal exposure assessments. MethodsEfficiency of metal accumulation was evaluated in fish intestine (brown trout, Salmo trutta Linnaeus, 1758), gammarids (Gammarus balcanicus Schäferna, 1922) and acanthocephalans (Dentitruncus truttae Sinzar, 1955) in the Krka River at site threatened by industrial and municipal wastewaters (Town of Knin) and reference site (Krka River source) in two seasons (autumn and spring). All samples were digested in a drying oven at 85 °C for 3.5 h using nitric acid and hydrogen peroxide. Samples were diluted with ultrapure water and total concentrations of 15 trace and macroelements were measured by HR ICP-MS. ResultsHigher concentrations of Co, Cu, Fe and Mn at the contaminated than at the reference site were recorded in all bioindicator organisms. Additionally, Se, Sr, Zn, Ca, K and Mg were elevated at the contaminated site in acanthocephalans, Cs, Pb, Zn and K in gammarids and Se, Sr and Ca in fish intestine. Opposite, concentrations of Cd, Cs and Rb were mostly higher in organisms from the reference than wastewater impacted site, which did not coincide with waterborne metal exposure but indicated importance of assessing dietary metal uptake. ConclusionMore effective metal accumulation was confirmed in acanthocephalans than fish and gammarids, especially of Cd and Pb in respect to gammarids, and of Cd, Cu, Pb, Mn and Sr in respect to fish intestine. Thus, both fish intestine and whole body of D. truttae were confirmed as sensitive indicators of low environmental metal exposure, reflecting site-specific differences, which proved their potential to be used in monitoring programmes and metal exposure assessment in real environmental situations.

Cambrian intra-oceanic subduction within the southern branch of the Proto-Tethyan Ocean: Constraints from rhyolites in the Lajishan suture, NE Tibetan Plateau

The South Qilian suture in the Qilian Orogen is an early Paleozoic belt that developed as a result of closure of the southern branch of the Proto-Tethyan Ocean. It is characterized by widespread Cambrian intermediate-basic volcanic rocks which record the early-stage evolution of the paleo-ocean basin. However, Cambrian evolution of the paleo-ocean basin remains controversial due to the lack of research on the age and tectonic affinity of these volcanic rocks. In this study, we identified rhyolites from the intermediate-basic volcanic rocks in the South Qilian suture. They occur as pebbles in the breccias, or as veins and interlayers within the intermediate-basic volcanic rocks. Zircon U-Pb datings yield ages of 514.0 ± 2.8 Ma, 521 ± 4 Ma, 523 ± 5 Ma, and 513 ± 9 Ma for four rhyolites, respectively. The Cambrian rhyolites show variable La/Sm ratios and Rb contents and positive zircon εHf(t) values (+6.8 to +14.6) and whole-rock εNd(t) values (+2.1 to +4.6), suggesting that they were derived from partial melting of juvenile mafic crust. They also have high Al2O3 and CaO contents, as well as low K2O and trace element concentrations, which are similar to those of oceanic arc rhyolite. These early Cambrian oceanic arc rhyolites, along with the SSZ-type ophiolite (ca. 530–520 Ma) to the north and late-stage granitoid intrusions (ca. 474–450 Ma), indicate that the southern branch of the Proto-Tethyan Ocean experienced southward intra-oceanic subduction during the early Cambrian-early Ordovician period.

Suppression of partially irreversible phase transition in O′3-Na3Ni2SbO6 cathode for sodium-ion batteries by interlayered structural modulation

As a promising cathode material for sodium ion batteries, honeycomb-ordered layered Na3Ni2SbO6 still suffers from rapid capacity fading because of partially irreversible phase transition. Herein, a substitution of Na+ by Rb+ with a larger ionic radius in honeycomb layered Na3−xRbxNi2SbO6 is proposed to modulate the interlayer structure. The results unveil that biphasic transition reversibility of the intermediate P′3 phase is substantially enhanced, and the structure evolution behavior during the charge/discharge process changes due to the structural modulation, which contributes to a suppression of the unfavorable O1 phase and an alleviation of the lattice distortion. Moreover, Rb substituted samples exhibited an improved Na+ (de)intercalation thermodynamics and kinetics. Attributed to the modifications, the sample with optimized Rb content delivers superior cycle stability and rate capacity, demonstrating a feasible strategy for suppressing irreversible phase transition and developing high-performance honeycomb layered materials for sodium ion batteries.

Mycorrhiza-mediated potassium transport in Medicago truncatula can be evaluated by using rubidium as a proxy

Arbuscular mycorrhizal (AM) fungi considerably improve plant nutrient acquisition, particularly phosphorus and nitrogen. Despite the physiological importance of potassium (K+) in plants, there is increasing interest in the mycorrhizal contribution to plant K+ nutrition. Yet, methods to track K+ transport are often costly and limiting evaluation opportunities. Rubidium (Rb+) is known to be transported through same pathways as K+. As such our research efforts attempt to evaluate if Rb+ could serve as a viable proxy for evaluating K+ transport in AM symbiosis. Therefore, we examined the transport of K+ in Medicago truncatula colonized by the AM fungus Rhizophagus irregularis isolate 09 having access to various concentrations of Rb+ in custom-made two-compartment systems. Plant biomass, fungal root colonization, and shoot nutrient concentrations were recorded under sufficient and limited K+ regimes. We report that AM plants displayed higher shoot Rb+ and K+ concentrations and a greater K+:Na+ ratio relative to non-colonized plants in both sufficient and limited K+ conditions. Consequently, our results indicate that Rb+ can be used as a proxy to assess the movement of K+ in AM symbiosis, and suggest the existence of a mycorrhizal uptake pathway for K+ nutrition in M. truncatula.

Distribution of selected trace elements in the major fractions of donkey milk

The aim of this study was to evaluate the concentrations of Zn, Cu, Mn, Se, Mo, Co, Li, B, Ti, Cr, Rb, Sr, Cd, and Pb in donkey milk and their distribution in major milk fractions (i.e., fat, casein, whey proteins, and aqueous phase). Individual milk samples were provided by 16 clinically healthy lactating donkeys. Subsequent centrifugation, ultracentrifugation, and ultrafiltration were carried out to remove fat, casein, and whey proteins to obtain skim milk, a supernatant whey fraction, and the aqueous phase of milk, respectively. Concentrations of the elements were measured in whole milk and fractions by inductively coupled plasma-mass spectrometry, and the concentrations associated with fat, casein, and whey proteins were then calculated. The effect of removal of fat, casein, and whey proteins was determined by repeated-measures ANOVA. The fat fraction of donkey milk carried a small (∼4.5% to 13.5%) but significant proportion of Mo, Co, Ti, Cr, and Sr. The casein fraction in donkey milk carried almost all milk Zn, a majority of Cu and Mn, and most of Mo, Ti, and Sr. Relevant proportions, between 20% and 36%, of Se, Co, and Cr were also associated with caseins. The majority of Se, Co, Li, B, Cr, and Rb, and relevant proportions of Mn, Mo, Ti, and Sr were found in soluble form (ultracentrifuged samples) and distributed between whey proteins and the aqueous phase of milk (ultrafiltered samples). Whey proteins in donkey milk carried the majority of milk Se and Co. All Li and B was present in the aqueous phase of milk, which also contained most Rb and Cr, and 17% to 42% of Mn, Se, Mo, Co, Ti, and Sr.

Formation of the Lened W-(Be) Skarn Deposit by Neutralization of a Magmatic Fluid—Evidence from H3BO3-Rich Fluids

Magmatic-hydrothermal systems, especially those causing the formation of tungsten deposits, may be enriched in boron, as is suggested by the presence of hydrothermal tourmaline. This study examines the boron and metal (including tungsten) concentrations of quartz-hosted fluid inclusions in the Lened W-(Be) deposit of the Canadian Cordillera and resolves (i) the analytical challenges involved during fluid salinity calculations of B-rich fluids and (ii) the relationship between fluid chemical composition and ore-forming processes involved at Lened. The aqueous fluid inclusions from this study have high CO2 and boron contents, indicated by the presence of a carbonic phase and sassolite crystals (H3BO3) in fluid inclusions. The boron content of the aqueous liquid phase (0.5 wt. %) was determined using microthermometric and Raman spectroscopic analyses. Boron was judged the most appropriate internal standard for quantifying the LA-ICP-MS data from these inclusions after calculation of salinity in the H2O-NaCl-H3BO3 system (3.5 to 5 wt. % NaCleq). Trace element data of the fluids show relatively high concentrations of Li (40 to 474 ppm), Al (56 to 1003 ppm), As (36 to 490 ppm) and Cs (68 to 296 ppm); and lower concentrations of Rb (3.6 to 77 ppm), Sr (0.4 to 23 ppm), Sb (1 to 32 ppm), Ba (0.6 to 163 ppm), Mg (6.9 to 7.6 ppm) and other metals, such as Be (2.4 to 10.2 ppm), W (2.4 to 27 ppm) and Cu (5.1 to 73 ppm). The high Cs and Li concentrations suggest a magmatic origin of the metals, while the moderate concentrations in Sr and Ba are indicative of fluid–rock interaction with the surrounding limestone. The presence of sassolite suggests that these fluids were highly acidic. The neutralization of this fluid through interaction with the surrounding limestone is the most probable trigger for scheelite precipitation. The presence of such high boron content in the magmatic fluid at Lened indicates the potential role in the enrichment of the source melt before fluid exsolution.