Intestinal mucin is a chaperone of multivalent copper.

Mucus protects the epithelial cells of the digestive and respiratory tracts from pathogens and other hazards. Progress in determining the molecular mechanisms of mucus barrier function has been limited by the lack of high-resolution structural information on mucins, the giant, secreted, gel-forming glycoproteins that are the major constituents of mucus. Here, we report how mucin structures we determined enabled the discovery of an unanticipated protective role of mucus: managing the toxic transition metal copper. Using two juxtaposed copper binding sites, one for Cu2+ and the other for Cu1+, the intestinal mucin, MUC2, prevents copper toxicity by blocking futile redox cycling and the squandering of dietary antioxidants, while nevertheless permitting uptake of this important trace metal into cells. These findings emphasize the value of molecular structure in advancing mucosal biology, while introducing mucins, produced in massive quantities to guard extensive mucosal surfaces, as extracellular copper chaperones.

Heavy metal and trace element alterations in patients during a migraine attack.

OBJECTIVE: The aim of the study was to determine the heavy metal and trace element (HMTE) profile in patients with migraine (PwM) and to compare it to that of healthy individuals without migraine. BACKGROUND: Migraine is a universal disease that affects more than 10% of the world's population; however, its pathophysiology is still obscure. METHODS: A total of 100 participants were included in this prospective matched case-control study (50 PwM during acute attack and 50 age- and sex-matched healthy controls). The study was conducted in the university hospital in Yozgat, Turkey, where the inductively coupled plasma mass spectrometry system was used to measure the HMTE profile. The calibration curve was created with 11 points for heavy metals (arsenic [As], cadmium [Cd], cobalt [Co], lead [Pb], mercury [Hg], nickel [Ni], and tin [Sn]) and trace elements (antimony [Sb], chromium [Cr], copper [Cu], iron [Fe], magnesium [Mg], manganese [Mn], molybdenum [Mo], and zinc [Zn]). RESULTS: The median age was 27 (23-37) years, and the female/male ratio was 37/13 for both groups. The PwM group had significantly higher As, Co, Pb, and Ni levels among the heavy metals (p = 0.033, 0.017, 0.022, and 0.021, respectively). Also, PwM had significantly lower Cr, Mg, and Zn levels among the trace elements (p = 0.007, 0.024, and < 0.001, respectively). The only trace element that was elevated in the PwM group was Mn (p = 0.001). The PwM and control groups did not differ in terms of Cd, Sn, Sb, Cu, Fe, and Mo (p = 0.165, 0.997, 0.195, 0.408, 0.440, and 0.252, respectively). CONCLUSION: Some HMTE parameters are altered in PwM, which may provide additional insight into understanding migraine etiology.

An overview of preconcentration techniques combined with inductively coupled plasma mass spectrometry for trace element determination in biological studies.

In the last decades, the determination of trace elements in biological materials has emerged as an important area of study because of its relevance to human health and the environment. Inductively coupled plasma mass spectrometry (ICP-MS) has proven to be a powerful tool for trace element analysis, owing to its high sensitivity and ability to determine several elements in a single measurement. However, given the complex nature of biological matrices and the presence of elements, most of them at ultratrace levels, it becomes crucial to complement ICP-MS with preconcentration techniques to increase the sensitivity and selectivity of analytical methods. This article presents an exhaustive overview of liquid- and solid-phase preconcentration techniques used in combination with ICP-MS for trace element determination in different biological samples from 2000 to the present. An in-depth discussion of the advances on the application of state-of-the-art solvents and materials in trace element extraction and preconcentration is presented. Special attention is given to different strategies for elemental speciation analysis, employing both chromatographic and non-chromatographic techniques. The role of automation in these methodologies is also described. Finally, future trends and challenges related to this topic are discussed.

A follow-up study on factors affecting the recovery of patients with hypothyroidism in different selenium environments.

BACKGROUND: Hypothyroidism is a major manifestation of autoimmune thyroid diseases (AITD). We previously reported that a low selenium (Se) status was linked to an elevated prevalence of thyroid diseases. We hypothesized that Se status may also influence the restoration of thyroid function. Thus, this study aimed to investigate the factors affecting the recovery of thyroid function in patients with (sub-)clinical hypothyroidism, with a specific focus on Se status. METHODS: We conducted a 6-year prospective cohort study comparing two counties with different Se concentrations. Demographic and disease data were collected from 1,190 individuals (549 Se-adequate and 641 Se-deficient) who completed a follow-up study in 2019. In addition, urinary iodine (I) levels, thyroid function, and serum and nail Se levels were measured. Logistic regression was used to investigate the relationship between Se deficiency and recovery of thyroid function. RESULTS: Sex and smoking status was similar between the two counties studied. Thyroid function recovery rate was significantly higher in Se-deficient counties (46.0% vs. 30.6%, P = 0.008). In the multivariate analysis, our results show that female sex (odds ratio [OR] (95% confidence interval [CI]) = 1.875 (1.080-3.257), P = 0.026] and increasing age [OR (95%CI) = 1.028(1.007-1.049), P = 0.009] were associated with the recovery rate. Additionally, our study revealed that while Se status was significant in the univariate analysis, this association appeared to disappear in the multivariate analysis. CONCLUSIONS: Female sex and increasing age have unfavorable effects on the recovery of thyroid function in patients over 30 years of age with (sub-) clinical hypothyroidism.

Spatiotemporal variability and drivers of water microchemistry in the upper Nu-Salween river: With implications for fish habitat conservation.

Microchemical maps, also known as "chemoscapes", hold immense potential for reconstructing fish habitat utilization and guiding conservation efforts. This approach relies on matching the microchemical composition of fish calcified structures (e.g., otoliths) with the surrounding water's microchemistry. However, applying this method faces a major challenge: a clear understanding of the spatiotemporal variability and drivers of water microchemistry, particularly in vast, free-flowing river ecosystems like the Nu-Salween River, Southeast Asia's longest free-flowing river. We analyzed the spatiotemporal variability and influencing factors of water microchemistry (i.e., Na:Ca, Mg:Ca, Mn:Ca, Cu:Ca, Zn:Ca, Se:Ca, Sr:Ca, and Ba:Ca) in the upper Nu-Salween River, based on a two-year sampling. Five elemental ratios (excluding Na:Ca, Mg:Ca, and Zn:Ca) in water demonstrated significant spatiotemporal variability, with Cu:Ca having the largest spatial variation, and Mn:Ca and Sr:Ca showing the greatest temporal variation. More specifically, four elemental ratios (Cu:Ca, Se:Ca, Sr:Ca, and Ba:Ca), exhibited significant variations along the longitudinal gradient, and Mn:Ca, Cu:Ca, Sr:Ca, and Ba:Ca, showed significant differences between mainstreams and tributaries. Temporally, Mn:Ca, Cu:Ca, and Ba:Ca displayed higher values and variations during the wet season, opposing the seasonal patterns of Na:Ca, Mg:Ca, and Sr:Ca. The four-element (Ba:Ca, Sr:Ca, Mg:Ca, and Mn:Ca) forest model showed the highest classification accuracy of 93%. Linear mixed-effects models showed that spatial factors have the largest influence on the variances in water microchemistry (56.36 ± 28.64%). Our study highlights the feasibility and reliability of utilizing microchemistry to reconstruct fish habitat utilization, thereby unveiling promising avenues for a more accurate understanding of fish life history in large rivers characterized by high heterogeneity in water microchemistry. By proportionally accounting for contribution of different factors to water microchemistry variability and relating them to microchemical composition of fish calcified structures, key fish habitats (e.g., spawning grounds) and migratory routes can be more precisely identified and thus protected.

Chemical characteristics and health risk evaluation of natural waters in the Du River Source National Nature Reserve: A case study in Zhushan County, Hubei Province, China.

To study the distribution of trace elements in natural water of the Du River Source National Nature Reserve and to assess the water quality and health risks, Zhushan County in Hubei Province was selected as the study area. Element content in 361 natural water samples collected from Zhushan County were measured by ICP-MS, ICP-OES, and HG-AFS. The main anions and cations present in water samples from Zhushan County are Ca2+ and HCO3-. The water chemistry is predominantly influenced by the weathering of carbonate rocks. The water samples with high content of selenium (Se) (0∼82.9 µg/L, mean 4.6 µg/L) in natural water in Zhushan County are mainly distributed in the northern part of Zhushan. The strontium (Sr) content of 49.6% of the water samples (0.001-2.177 mg/L, mean 0.234 mg/L) reached the criteria of natural mineral water for drinking in China (Sr ≥ 0.2 mg/L), which is distributed throughout the county. The high content of metasilicic acid (H2SiO3) (0.026-35.910 mg/L, mean 12.598 mg/L) and zinc (Zn) (0∼407.218 µg/L, mean 12.406 µg/L) are concentrated in northern Zhushan County. 99.7% water samples were freshwater and 98.9% meet the criteria of "good" water quality. All of the natural water samples have low health risk and low heavy metal pollution. 6.1% water samples meet the criteria of Se-type mineral water, while 45.4% meet the criteria of Sr-type mineral water, and 4.4% water samples meet the criteria of "low sodium, high Se, and high Sr" mineral water. Zhushan County has the potential for Se-type mineral water and Sr-type mineral water development. The findings of this study hold immense significance for the public health implications of drinking water in Du River Source, thereby offering valuable insights for effective water resources management.

The key role of major and trace elements in the formation of five common urinary stones.

BACKGROUND: Urolithiasis has emerged as a global affliction, recognized as one of the most excruciating medical issues. The elemental composition of stones provides crucial information, aiding in understanding the causes, mechanisms, and individual variations in stone formation. By understanding the interactions between elements in various types of stones and exploring the key role of elements in stone formation, insights are provided for the prevention and treatment of urinary stone disease. METHODS: This study collected urinary stone samples from 80 patients in Beijing. The chemical compositions of urinary stones were identified using an infrared spectrometer. The concentrations of major and trace elements in the urinary stones were determined using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS), respectively. The data were processed using correlation analysis and Principal Component Analysis (PCA) methods. RESULTS: Urinary stones are categorized into five types: the calcium oxalate (CO) stone, carbonate apatite (CA) stone, uric acid (UA) stone, mixed CO and CA stone, and mixed CO and UA stone. Ca is the predominant element, with an average content ranging from 2.64 to 27.68% across the five stone groups. Based on geochemical analysis, the high-content elements follow this order: Ca > Mg > Na > K > Zn > Sr. Correlation analysis and PCA suggested significant variations in the interactions between elements for different types of urinary stones. Trace elements with charges and ionic structures similar to Ca may substitute for Ca during the process of stone formation, such as Sr and Pb affecting the Ca in most stone types except mixed stone types. Moreover, the Mg, Zn and Ba can substitute for Ca in the mixed stone types, showing element behavior dependents on the stone types. CONCLUSION: This study primarily reveals distinct elemental features associated with five types of urinary stones. Additionally, the analysis of these elements indicates that substitutions of trace elements with charges and ion structures similar to Ca (such as Sr and Pb) impact most stone types. This suggests a dependence of stone composition on elemental behavior. The findings of this study will enhance our ability to address the challenges posed by urinary stones to global health and improve the precision of interventions for individuals with different stone compositions.

Micronutrient Status and Breast Cancer: A Narrative Review.

Breast cancer is one of the most common cancers worldwide, at the same time being one of the most prevalent causes of women's death. Many factors such as alcohol, weight fluctuations, or hormonal replacement therapy can potentially contribute to breast cancer development and progression. Another important factor in breast cancer onset includes micronutrient status. In this narrative review, we analyzed 23 micronutrients and their possible influence on breast cancer onset and progression. Further, the aim of this study was to investigate the impact of micronutrient status on the prevention of breast cancer and its possible influence on various therapeutic pathways. We researched meta-analyses, systemic and narrative reviews, retrospective studies, as well as original studies on human and animal models. The results of these studies indicate a possible correlation between the different levels of micronutrients and a decreased risk of breast cancer as well as a better survival rate. However, further studies are necessary to establish adequate doses of supplementation of the chosen micronutrients and the exact mechanisms of micronutrient impact on breast cancer therapy.

Dissolved trace elements in the Ganges-Brahmaputra-Meghna River Basin: A new approach for estimating trace element flux inputs from rivers into the world's oceans.

Understanding the changes in the chemical compositions of dissolved trace elements from source to sink is important for determining their spatiotemporal variations and the contributions from each sub-catchment in the Ganges, Brahmaputra, and Meghna Rivers. To estimate weathering and matter transfer in these Rivers and the Ganges-Brahmaputra-Meghna (G-B-M) Estuary, we measured 15 dissolved trace element concentrations from surface and bottom water samples and exchangeable trace metals from suspended particulate matter (SPM). From December 2019 to January 2020, post-monsoon samples were collected from the upstream of the three rivers and the G-B-M Estuary. Dissolved trace elements in the Ganges and Meghna Rivers exhibited remarkable spatial variations, whereas those in the Brahmaputra River and the G-B-M Estuary were uniform. The dissolved trace elements, basic information (river length and drainage area), and physicochemical parameters (pH, dissolved oxygen, and conductivity) of the three rivers were inconsistent. The sample sites near urban areas and industrial centers had high concentrations of dissolved trace elements. In the G-B-M Estuary, iron and lead concentrations decreased along the salinity gradient, whereas selenium levels gradually increased, which may have been released by the SPM owing to its highly exchangeable trace metals. Compared with historical concentrations, trace elements that entered the G-B Estuary from the Ganges and Brahmaputra Rivers exhibited either decreased or increased metal fluxes due to additional terrigenous sources, suggesting that the inputs of trace element flux from the Ganges and Brahmaputra Rivers into the oceans may need to be re-evaluated. Furthermore, Fe and Pb concentrations and river fluxes in the Ganges and Changjiang have decreased in recent years. Hence, the fluxes of certain trace elements that enter the oceans from large rivers may require re-evaluation.

Does transplanted Posidonia oceanica act as a sink or source of trace elements? Ecological implications for restoring polluted coastal areas.

Despite the high potential of seagrass restoration to reverse the trend of marine ecosystem degradation, there are still many limitations, especially when ecosystems are severely degraded. In particular, it is not known whether restoring polluted ecosystems can lead to potentially harmful effects associated with contaminant remobilisation. Here, we aimed to investigate the role of P. oceanica transplanted from a pristine meadow to a polluted site (Augusta Bay, Italy, Mediterranean Sea) in two seasons of the year, as a sink or source of trace elements to the environment. The main results showed i) higher accumulation of chromium (Cr), copper (Cu) and total mercury (THg) in plants transplanted in summer than in winter, as well as an increase in Cr and THg in plants from sites with higher trace element loads; ii) an increase in leaf phenolics and a decrease in rhizome soluble carbohydrates associated with As and THg accumulation, suggesting the occurrence of defence strategies to cope with pollution stress; iii) a different partitioning of trace elements between below- and above-ground tissues, with arsenic (As) and Cr accumulating in roots, whereas Cu and THg in both roots and leaves. These results suggest that P. oceanica transplanted to polluted sites can act as both a sink and a source, sequestering trace elements in the below-ground tissues thus reducing their bioavailability, but also potentially remobilising them. However, the amount of trace elements potentially exported from P. oceanica to the environment through transfer into food webs via leaves and detritus appeared to be low under the specific conditions of the study site. Although further research into seagrass restoration of polluted sites would improve current knowledge to support effective ecosystem-based coastal management, the benefits of restoring polluted sites through seagrass transplantation appear to outweigh the potential costs of inaction over time.

Risk assessment of trace elements in vegetables grown in river Yamuna floodplain in Delhi.

Urban agriculture is common in fertile river floodplains of many developing countries. However, there is a risk of contamination in highly polluted regions. This study quantifies health risks associated with the consumption of vegetables grown in the floodplain of the urban river 'Yamuna' in the highly polluted yet data-scarce megacity Delhi, India. Six trace elements are analyzed in five kinds of vegetable samples. Soil samples from the cultivation area are also analyzed for elemental contamination. Ni, Mn, and Co are observed to be higher in leafy vegetables than others. Fruit and inflorescence vegetables are found to have higher concentrations of Cr, Pb, and Zn as compared to root vegetables. Transfer Factor indicates that Cr and Co have the highest and least mobility, respectively. Vegetable Pollution Index indicates that contamination levels follow as Cr > Ni > Pb > Zn. Higher Metal Pollution Index of leafy and inflorescence vegetables than root and fruit vegetables indicate that atmospheric deposition is the predominant source. Principal Component Analysis indicates that Pb and Cr have similar sources and patterns in accumulation. Among the analyzed vegetables, radish may pose a non-carcinogenic risk to the age group of 1-5 year. Carcinogenic risk is found to be potentially high due to Ni and Cr accumulation. Consumption of leafy vegetables was found to have relatively less risk than other vegetables due to lower Cr accumulation. Remediation of Cr and Ni in floodplain soil and regular monitoring of elemental contamination is a priority.

Heavy metal and metalloid concentrations in red deer (Cervus elaphus) and their human health implications from One Health perspective.

The red deer is an ungulate and large game species. The contamination of the ecosystems by metal(loid)s may lead to the exposure of animals (as well as humans) through water and food resources. The direct contact of hunters and wild animal meat consumers with deer carcasses may be a potential contaminant source. This study aimed to determine the metal(loid)s' concentrations in the liver and kidney of red deer from two regions of Portugal (Idanha-a-Nova and Lousã), and to relate these with histopathologic lesions. Thirteen young male deer were submitted to metal(loid) determination (As, Cd, Co, Cr, Cu, Pb, and Zn) by inductively coupled plasma mass spectrophotometry (ICP-MS) and histopathology examination. Renal Cd (8.072 ± 5.766 mg/kg dw) and hepatic Pb (3.824 ± 6.098 mg/kg dw) mean values were high, considering the maximum values for consumption established by the European Commission. The hepatic mean value of Cu was significantly higher in Idanha-a-Nova (150.059 ± 33.321 mg/kg dw), and it is at the Cu toxicity limit considered for ruminants (150 mg/kg). The pollution induced by Panasqueira mines (Castelo Branco) may be a possible explanation for some of the findings, especially the higher values of hepatic Cu and Pb found in Idanha-a-Nova deer. These results have high importance under a One Health perspective, since they have implications in public health, and pose at risk the imbalance of animal populations and ecosystems.

Effect of Genotype on Cadmium and Trace Element Accumulation in Wheat from Weakly Alkaline Cadmium-contaminated Soil.

Cadmium (Cd) contamination of farmland soils leads to Cd accumulation in crops and reduced micronutrient uptake, posing grave risks to food safety. Herein, we investigated the enrichment and transportation patterns of Cd and trace elements in different parts of six wheat genotypes grown in weakly alkaline Cd-contaminated soils via pot experiments. The results revealed that the wheat grain variety with high Cd accumulation (Ningmai13) demonstrated a 1.94-fold increase compared to the variety with low accumulation (Yanong0428). The transfer factor of Cd from wheat straw to grain ranged from 0.319 to 0.761, while the transfer factor of Cd from root to straw ranged from 0.167 to 0.461. Furthermore, the concentrations of other metals in wheat grains followed the order of Zn > Mn > Fe > Cu. There was a significant positive correlation between Cd and Mn in grains, indicating a potential synergistic effect. Overall, this study provides valuable insights into the regulation of micronutrient intake to modulate Cd uptake in wheat.

A new clustering model based on the seminal plasma/serum ratios of multiple trace element concentrations in male patients with subfertility.

Purpose: To investigate whether seminal plasma (SP)/serum ratios of multiple trace elements (TEs) can classify patients with male subfertility. Methods: SP/serum ratios of 20 TEs (lithium, sodium, magnesium, phosphorus, sulfur, potassium, calcium, manganese, iron, cobalt, copper, zinc, arsenic, selenium, rubidium, strontium, molybdenum, cesium, barium, and thallium) were calculated for healthy volunteers (n = 4) and those consulting for male subfertility (n = 245). Volunteer semen samples were collected by split ejaculation into early and subsequent fractions, and SP/serum ratio data were compared between fractions. The patients' SP/serum ratio data were used in an unsupervised clustering analysis and qualitatively compared with the data from the fractions of ejaculation from the volunteers. Semen quality parameters and pregnancy outcomes were compared between patient clusters. Results: The early fraction of volunteers was characterized by lower phosphorus and arsenic and 18 other higher TEs than the subsequent fraction. Cluster analysis classified patients into four distinct clusters, one sharing characteristics with the early fraction and another with the subsequent fraction. One cluster with the early fraction characteristics had significantly lower semen volume and higher pregnancy rates from spontaneous pregnancies or intrauterine insemination. Conclusions: Classification of patients based on SP/serum ratios of multiple TEs represents the dominance of fractions of ejaculation samples.

Determination of potentially toxic elements and health risk assessment of dried fruits.

This study aims to measure the concentrations of As, Cd, Pb, Cr, and Ni in dried fruits and examine the health effects of these trace metals in relation to people's daily dietary intake. 29 samples of dried fruits purchased at bazaar place were analyzed in terms of toxic elements, which have been reported as cancerous by the World Health Organization (WHO). Dried fruits were digested in a microwave oven with HNO3 and H2O2. Metal concentrations (As, Cd, Cr, Ni, and Pb) in these samples were measured using inductively coupled plasma mass spectrometry (ICP-MS). Linearity, limit of detection (LOD), limit of quantification (LOQ), specificity/selectivity, and recovery (%) were all evaluated. The correlation coefficients of elements in this method were good (R2 > 0.9997). The amount of consumption in the area was used to calculate a health risk assessment. The results showed that the samples of dried fruit, which are widely consumed in the identified area, had variable levels. All dried fruits had element concentrations that were lower than the WHO/FAO safe limit.

Genetic dissection of maize (Zea maysL.) trace element traits using genome-wide association studies.

Maize (Zea mays L.) is an important food and feed crop worldwide and serves as a a vital source of biological trace elements, which are important breeding targets. In this study, 170 maize materials were used to detect QTNs related to the content of Mn, Fe and Mo in maize grains through two GWAS models, namely MLM_Q + K and MLM_PCA + K. The results identified 87 (Mn), 205 (Fe), and 310 (Mo) QTNs using both methods in the three environments. Considering comprehensive factors such as co-location across multiple environments, strict significance threshold, and phenotypic value in multiple environments, 8 QTNs related to Mn, 10 QTNs related to Fe, and 26 QTNs related to Mo were used to identify 44 superior alleles. Consequently, three cross combinations with higher Mn element, two combinations with higher Fe element, six combinations with higher Mo element, and two combinations with multiple element (Mn/Fe/Mo) were predicted to yield offspring with higher numbers of superior alleles, thereby increasing the likelihood of enriching the corresponding elements. Additionally, the candidate genes identified 100 kb downstream and upstream the QTNs featured function and pathways related to maize elemental transport and accumulation. These results are expected to facilitate the screening and development of high-quality maize varieties enriched with trace elements, establish an important theoretical foundation for molecular marker assisted breeding and contribute to a better understanding of the regulatory network governing trace elements in maize.

Assessment of 13 essential and toxic trace elements in tumor and peritumoral brain tissues from human glioblastoma.

Trace elements within the brain are important for proper neurological function, but their imbalance has been rarely investigated in glioblastoma. This study enrolled a total of 14 patients with glioblastoma, and the tumor and peritumoral brain tissues were collected while undergoing surgery. The concentrations of Mg, Ca, Cr, Mn, Fe, Co, Cu, Zn, Se, As, Cd, Tl and Pb were determined using a well-evaluated ICP-MS method. The Cu- and Cd-binding proteomes were further analyzed using the anatomic transcriptional atlas from Ivy GAP. Histological evaluation was based on rubeanic acid staining and immunohistochemistry, respectively. The 13 trace element concentrations were obtained, and the highest were Ca, Mn, Fe, Zn and Cu, ranging from a few to dozens of ug/g. Correlation analysis suggested the existence of two intra-correlated clusters: essential metals (Cu-Ca-Zn-Mg) and heavy metals (Pb-As-Cd-Tl-Co-Cr-Mn). Compared to the tumor samples, significantly higher levels of Cu and Cd were observed in the peritumoral region. Further analysis of the Cu- and Cd-binding proteins from the anatomic view suggested that DBH and NOS1 were obviously increased in the leading edge than the central tumor region. Consistent with the above findings, histological evaluation of Cu and DBH further confirmed more copper and DBH expressions in the peritumoral area compared to the tumor core. Trace elements differ in tumor and peritumoral brain zone in glioblastoma, which may associate with tumor angiogenesis.

Ecosystem bioelement variability is associated with freshwater animal aggregations at the aquatic-terrestrial interface.

The impacts of animals on the biogeochemical cycles of major bioelements like C, N, and P are well-studied across ecosystem types. However, more than 20 elements are necessary for life. The feedbacks between animals and the biogeochemical cycles of the other bioelements are an emerging research priority. We explored how much freshwater mussels (Bivalvia: Unionoida) were related to variability in ecosystem pools of 10 bioelements (Ca, Cu, Fe, K, Mn, Na, Mg, P, S and Zn) in streams containing a natural mussel density gradient in the US Interior Highlands. We studied the concentrations of these bioelements across the aquatic-terrestrial interface-in the porewater of riverine gravel bars, and the emergent macrophyte Justicia americana. Higher mussel density was associated with increased calcium in gravel bars and macrophytes. Mussel density also correlated with variability in iron and other redox-sensitive trace elements in gravel bars and macrophytes, although this relationship was mediated by sediment grain size. We found that two explanations for the patterns we observed are worthy of further research: (1) increased calcium availability in gravel bars near denser mussel aggregations may be a product of the buildup and dissolution of shells in the gravel bar, and (2) mussels may alter redox conditions, and thus elemental availability in gravel bars with fine sediments, either behaviorally or through physical structure provided by shell material. A better understanding of the physical and biogeochemical impacts of animals on a wide range of elemental cycles is thus necessary to conserve the societal value of freshwater ecosystems.

Trace element partitioning in basaltic systems as a function of oxygen fugacity.

Along with temperature, pressure and melt chemistry, magmatic oxygen fugacity (fO2) has an important influence on liquid and solid differentiation trends and melt structure. To explore the effect of redox conditions on mineral stability and mineral-melt partitioning in basaltic systems we performed equilibrium, one-atmosphere experiments on a picrite at 1200-1110 °C with fO2 ranging from NNO-4 log units to air. Clinopyroxene crystallizes from 1180 °C to near-solidus, along with plagioclase, olivine and spinel. Olivine Mg# increases with increasing fO2, eventually reacting to pigeonite. Spinel is absent under strongly reducing conditions. Mineral-melt partition coefficients (D) of redox-sensitive elements (Cr, Eu, V, Fe) vary systematically with fO2 and, in some cases, temperature (e.g. DCr in clinopyroxene). Clinopyroxene sector zoning is common; sectors along a- and b-axes have higher AlIV, AlVI, Cr and Ti and lower Mg than c-axis sectors. In terms of coupled substitutions, clinopyroxene CaTs (MgSi = AlVIAlIV) prevails under oxidized conditions (≥ NNO), where Fe3+ balances the charge, but is limited under reduced conditions. Overall, AlIV is maximised under high temperature, oxidizing conditions and in slowly grown (a-b) sectors. High AlIV facilitates incorporation of REE (REEAlIV = CaSi), but DREE (except DEu) show no systematic dependence on fO2 across the experimental suite. In sector zoned clinopyroxenes enrichment in REE3+ in Al-rich sectors is quantitatively consistent with the greater availability of suitably-charged M2 lattice sites and the electrostatic energy penalty required to insert REE3+ onto unsuitably-charged M2 sites. By combining our experimental results with published data, we explore the potential for trace element oxybarometry. We show that olivine-melt DV, clinopyroxene-melt DV/DSc and plagioclase-melt DEu/DSr all have potential as oxybarometers and we present expressions for these as a function of fO2 relative to NNO. The crystal chemical sensitivity of heterovalent cation incorporation into clinopyroxene and the melt compositional sensitivity of the Eu2+-Eu3+ redox potential limit the use of clinopyroxene-melt and plagioclase-melt, however, olivine-melt DV affords considerable precision and accuracy as an oxybarometer that is independent of temperature, and crystal and melt composition. Variation of DV and DV/DSc with fO2 for olivine and clinopyroxene contains information on redox speciation of V in coexisting melt. By comparing the redox speciation constraints from partitioning to data from Fe-free synthetic systems and XANES spectroscopy of quenched glasses, we show that homogenous equilibria involving Fe and V species modify V speciation on quench, leading to a net overall reduction in the average vanadium valence. Mineral-melt partitioning of polyvalent species can be a useful probe of redox speciation in Fe-bearing systems that is unaffected by quench effects. Supplementary Information: The online version contains supplementary material available at 10.1007/s00410-023-02069-x.

High preoperative serum strontium levels increase the risk of acute kidney injury after cardiopulmonary bypass.

BACKGROUND: Acute kidney injury (AKI) is a common complication of cardiac surgeries. The incidence of AKI after cardiac surgeries using cardiopulmonary bypass (CPB-AKI) is high, emphasizing the need to determine strategies to prevent CPB-AKI. This study investigates the correlation between CPB-AKI and trace metal levels in clinical and animal studies. METHODS: Samples and clinical data were obtained from 74 patients from the Nagoya City University Hospital and Okazaki City Hospital. Blood samples were collected before, immediately after, and 2 h after CPB withdrawal. Trace metal levels were measured using inductively coupled plasma mass spectrometry. Sr or vehicle treatment was orally administered to the rats to determine if Sr was associated with CPB-AKI. After the treatment, ischemia-reperfusion (IR) injury was induced, and serum creatinine (SCr) and blood urea nitrogen (BUN) levels were measured. RESULTS: In this clinical study, the incidence of CPB-AKI was found to be 28% (21/74). The body mass index and estimated glomerular filtration rate were significantly different in patients with AKI. The intensive care unit and hospital stay were longer in AKI patients than in non-AKI patients. The Na, Fe, and Sr levels were significantly higher in AKI patients before CPB. Also, Fe and Sr were higher immediately after CPB withdrawal, and Sr was higher 2 h after CPB withdrawal in AKI patients. Animal studies showed that Sr-treated rats had significantly increased SCr and BUN levels than vehicle-treated rats at 24 h post-IR injury. CONCLUSIONS: High preoperative serum Sr levels may be associated with CPB-AKI.