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Accurately determining the phase states of barium carbonate, barium silicate, and barium sulfate in ores. It’s crucial for advancing research on barium ore mineralization and improving beneficiation and smelting processes. This study aimed to investigate the integration of phase analysis and X-ray fluorescence spectrometry(XRF) to assess the phases of barium in ores, only requiring simple sample pretreatment before measurement. The acetic acid separation drip method was used for the determination of barium carbonate, while the hydrochloric acid separation drip method was used for barium silicate. Additionally, the fusion sample preparation method was applied for the analysis of barium sulfate. The results were consistent with those obtained using chemical methods, and the precision of the relative standard deviation(RSD) was less than or equal to 2.74%, satisfying the analytical requirements. This study combines chemical separation with XRF for continuous and precise phase determination. This approach enhances applicability of XRF in chemical phase analysis and provides a simpler, more environmentally friendly alternative to traditional techniques. It can be applied to barium phase analysis in general barium ores.

There is an increasing public awareness of the relatively new and expanded industrial barium uses which are potential sources of human exposure (e.g., a shale gas development that causes an increased awareness of environmental exposures to barium). However, absorption of barium in exposed humans and a full spectrum of its health effects, especially among chronically exposed to moderate and low doses of barium populations, remain unclear. We suggest a systematic literature review (from 1875 to 2014) on environmental distribution of barium, its bioaccumulation, and potential and proven health impacts (in animal models and humans) to provide the information that can be used for optimization of future experimental and epidemiological studies and developing of mitigative and preventive strategies to minimize negative health effects in exposed populations. The potential health effects of barium exposure are largely based on animal studies, while epidemiological data for humans, specifically for chronic low-level exposures, are sparse. The reported health effects include cardiovascular and kidney diseases, metabolic, neurological, and mental disorders. Age, race, dietary patterns, behavioral risks (e.g., smoking), use of medications (those that interfere with absorbed barium in human organism), and specific physiological status (e.g., pregnancy) can modify barium effects on human health. Identifying, evaluating, and predicting the health effects of chronic low-level and moderate-level barium exposures in humans is challenging: Future research is needed to develop an understanding of barium bioaccumulation in order to mitigate its potential health impacts in various exposured populations. Further, while occupationally exposed at-risk populations exist, it is also important to identify potentially vulnerable subgroups among non-occupationally exposed populations (e.g., elderly, pregnant women, children) who are at higher risk of barium exposure from drinking water and food.

Reconstructing hydrological conditions of past warm periods, such as the Eocene ‘hot house’ provides empirical data to compare to state of the art climate models. However, reconstructing these changes in deep time is challenging, for example, given the complex interplay between evapotranspiration, precipitation and runoff. As a proxy for past changes in these hydrological systems, the dynamics of fresh water input into marginal seas can be used to identify the spatiotemporal distribution of riverine runoff. Elemental barium (Ba) and radiogenic strontium ( 87 Sr) are, depending on the amount of runoff and the background geology of the catchment area, typically enriched in river waters in comparison to seawater and can thus be utilized to determine changes in riverine fresh water discharge. Here, we use barium to calcium ratios (Ba/Ca) and radiogenic strontium isotopes ( 87 Sr/ 86 Sr) measured in fossil bivalve shells to reconstruct patterns of fresh water input into the paleo North Sea during the early to middle Eocene. Our reconstruction shows the potential of Ba/Ca and 87 Sr/ 86 Sr to serve as proxies for riverine runoff and highlights the spatiotemporal complexity of Eocene hydrological conditions in western Europe. In particular, our results enable changes in riverine input along geological to perennial time scales for different coastal regions to be determined, revealing a steady influx of fresh water, but with distinct spatiotemporal differences.

Arsenic contamination of shallow groundwater is among the biggest health threats in the developing world. Targeting uncontaminated deep aquifers is a popular mitigation option although its long-term impact remains unknown. Here we present the alarming results of a large-scale groundwater survey covering the entire Red River Delta and a unique probability model based on three-dimensional Quaternary geology. Our unprecedented dataset reveals that ~7 million delta inhabitants use groundwater contaminated with toxic elements, including manganese, selenium, and barium. Depth-resolved probabilities and arsenic concentrations indicate drawdown of arsenic-enriched waters from Holocene aquifers to naturally uncontaminated Pleistocene aquifers as a result of > 100 years of groundwater abstraction. Vertical arsenic migration induced by large-scale pumping from deep aquifers has been discussed to occur elsewhere, but has never been shown to occur at the scale seen here. The present situation in the Red River Delta is a warning for other As-affected regions where groundwater is extensively pumped from uncontaminated aquifers underlying high arsenic aquifers or zones.

The patterning of barium in tooth enamel is shown to be a reliable marker of lactation in humans and macaques; furthermore, the study of a tooth from a Neanderthal child reveals the weaning process in this extinct species. Dental barium a marker for weaning in primates Weaning is a critical time in the life of any mammal, particularly for humans, in which early weaning allows women to have more babies in a shorter period of time than would otherwise be possible. The development of early weaning, therefore, could have had a profound influence on the evolution and success of Homo sapiens . Until now it has not been possible to determine age of weaning from fossils with any accuracy, but here Manish Arora and colleagues show that the ratio of barium to calcium in tooth enamel is a reliable marker of lactation in humans and macaques. Barium rises during lactation and drops abruptly on weaning. The study of a tooth from a well-preserved Belgian Neanderthal reveals the duration of exclusive breastfeeding, the period of a mixed diet, and a remarkably early age at weaning of about 14 months. Early-life dietary transitions reflect fundamental aspects of primate evolution and are important determinants of health in contemporary human populations 1 , 2 . Weaning is critical to developmental and reproductive rates; early weaning can have detrimental health effects but enables shorter inter-birth intervals, which influences population growth 3 . Uncovering early-life dietary history in fossils is hampered by the absence of prospectively validated biomarkers that are not modified during fossilization 4 . Here we show that large dietary shifts in early life manifest as compositional variations in dental tissues. Teeth from human children and captive macaques, with prospectively recorded diet histories, demonstrate that barium (Ba) distributions accurately reflect dietary transitions from the introduction of mother’s milk through the weaning process. We also document dietary transitions in a Middle Palaeolithic juvenile Neanderthal, which shows a pattern of exclusive breastfeeding for seven months, followed by seven months of supplementation. After this point, Ba levels in enamel returned to baseline prenatal levels, indicating an abrupt cessation of breastfeeding at 1.2 years of age. Integration of Ba spatial distributions and histological mapping of tooth formation enables novel studies of the evolution of human life history, dietary ontogeny in wild primates, and human health investigations through accurate reconstructions of breastfeeding history.

Cyanobacteria have affected major geochemical cycles (carbon, nitrogen, and oxygen) on Earth for billions of years. In particular, they have played a major role in the formation of calcium carbonates (i.e., calcification), which has been considered to be an extracellular process. We identified a cyanobacterium in modern microbialites in Lake Alchichica (Mexico) that forms intracellular amorphous calcium-magnesium-strontium-barium carbonate inclusions about 270 nanometers in average diameter, revealing an unexplored pathway for calcification. Phylogenetic analyses place this cyanobacterium within the deeply divergent order Gloeobacterales. The chemical composition and structure of the intracellular precipitates suggest some level of cellular control on the biomineralization process. This discovery expands the diversity of organisms capable of forming amorphous calcium carbonates.

When reporting results of Gunshot Residue (GSR) analysis from a person suspected to be involved in a recent shooting, most forensic experts only provide the court with the raw results (i.e. the number of GSR particles found) and a disclaimer that a positive finding does not prove that the suspect was involved in a firearm shooting incident whilst a negative finding does not prove that he was not. Probabilistic analysis of the GSR results provides more value to the court, so the present study calculated likelihood ratio (LR) values for finding 0–8 characteristic GSR particles (containing Lead, Barium and Antimony) on a suspect's hands, based on the available GSR data from the published literature as well as studies by the authors. Defense propositions, i.e. modes for GSR acquisition other than involvement in a shooting event, were divided into three broad categories: low, medium and heavy background. For each background level and number of GSR particles found, minimal and maximal LR values were calculated. Thus, for each proposition the defense provides for the presence of GSR on the defendant's hands, the forensic expert can provide a possible set of minimal and maximal LR values, leaving the court to examine the defendant's contention and decide which of the three background modes is more plausible according to the circumstances of the specific case. •We calculate likelihood ratio values for finding characteristic GSR particles on a suspect.•Defense propositions are divided into three broad categories: low, medium and heavy background.•LR calculations are based on the available GSR data from published literature and studies.

BackgroundLocated in Northeastern British Columbia, the Montney formation is an important area of unconventional oil and gas exploitation, which can release contaminants like trace elements. Gestational exposure to these contaminants may lead to deleterious developmental effects.ObjectivesOur study aimed to (1) assess gestational exposure to trace elements in women living in this region through repeated urinary measurements; (2) compare urinary concentrations to those from North American reference populations; (3) compare urinary concentrations between Indigenous and non-Indigenous participants; and (4) evaluate inter- and intra-individual variability in urinary levels.MethodsEighty-five pregnant women participating in the Exposures in the Peace River Valley (EXPERIVA) study provided daily spot urine samples over 7 consecutive days. Samples were analyzed for 20 trace elements using inductively-coupled mass spectrometry (ICP-MS). Descriptive statistics were calculated, and inter- and intra-individual variability in urinary levels was evaluated through intraclass correlation coefficient (ICC) calculation for each trace element.ResultsWhen compared with those from North American reference populations, median urinary levels were higher in our population for barium (~2 times), cobalt (~3 times) and strontium (~2 times). The 95th percentile of reference populations was exceeded at least 1 time by a substantial percentage of participants during the sampling week for barium (58%), cobalt (73%), copper (29%), manganese (28%), selenium (38%), strontium (60%) and vanadium (100%). We observed higher urinary manganese concentrations in self-identified Indigenous participants (median: 0.19 µg/g creatinine) compared to non-Indigenous participants (median: 0.15 µg/g of creatinine). ICCs varied from 0.288 to 0.722, indicating poor to moderate reliability depending on the trace element.SignificanceOur results suggest that pregnant women living in this region may be more exposed to certain trace elements (barium, cobalt, copper, manganese, selenium, strontium, and vanadium), and that one urine spot sample could be insufficient to adequately characterize participants’ exposure to certain trace elements.Impact statementUnconventional oil and gas (UOG) is an important industry in the Peace River Valley region (Northeastern British Columbia, Canada). Information on the impacts of this industry is limited, but recent literature emphasizes the risk of environmental contamination. The results presented in this paper highlight that pregnant women living near UOG wells in Northeastern British Columbia may be more exposed to some trace elements known to be related to this industry compared to reference populations. Furthermore, our results based on repeated urinary measurements show that one urine sample may be insufficient to adequately reflect long-term exposure to certain trace elements.

The study of spatio-temporal variability of airborne bacterial communities has recently gained importance due to the evidence that airborne bacteria are involved in atmospheric processes and can affect human health. In this work, we described the structure of airborne microbial communities in two urban areas (Milan and Venice, Northern Italy) through the sequencing, by the Illumina platform, of libraries containing the V5–V6 hypervariable regions of the 16S rRNA gene and estimated the abundance of airborne bacteria with quantitative PCR (qPCR). Airborne microbial communities were dominated by few taxa, particularly Burkholderiales and Actinomycetales, more abundant in colder seasons, and Chloroplasts, more abundant in warmer seasons. By partitioning the variation in bacterial community structure, we could assess that environmental and meteorological conditions, including variability between cities and seasons, were the major determinants of the observed variation in bacterial community structure, while chemical composition of atmospheric particulate matter (PM) had a minor contribution. Particularly, Ba, SO₄²⁻and Mg²⁺concentrations were significantly correlated with microbial community structure, but it was not possible to assess whether they simply co-varied with seasonal shifts of bacterial inputs to the atmosphere, or their variation favoured specific taxa. Both local sources of bacteria and atmospheric dispersal were involved in the assembling of airborne microbial communities, as suggested, to the one side by the large abundance of bacteria typical of lagoon environments (Rhodobacterales) observed in spring air samples from Venice and to the other by the significant effect of wind speed in shaping airborne bacterial communities at all sites.

Breast milk is considered the best source of nutrition for all infants. However, exposure of newborns to toxic metals is of special interest due to their potential harmful effects. Thus, the primary aims of this study were to determine the concentration of toxic heavy metals including lead, mercury, cadmium, and barium in breast milk samples from Hamadan, Iran, in relation to some sociodemographic variables. A total of 100 breast milk samples were collected and their heavy metal contents were measured by inductively coupled plasma mass spectroscopy (ICP-MS). The median breast milk concentrations of Pb, Hg, and Ba were 41.9, 2.8, and 1.95 μg/L, respectively. Cd levels were < 1 μg/L in all samples. The Pb level in 94% of the samples was higher than the recommended Pb limit of < 5 μg/L in breast milk suggested by World Health Organization (WHO). Hg levels in 54% of the breast milk samples were higher than the normal mean concentration (1.7 μg/L) suggested by WHO. We found no correlation between Hg levels in breast milk and sociodemographic factors. Ba levels in all the breast milk samples were lower than the WHO’s proposed health-based drinking water guideline (0.7 mg/L). Considering the results of the present study and the vulnerability of infants, along with the well-known toxicity of these metals, further studies are warranted to identify the main sources of exposure that contribute their concentration in breast milk, establish harmless intake values of toxic metals in breast milk, and develop preventive measures.