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We investigate the native point defects in the long-wavelength infrared (LWIR) detector material H g 0.75 C d 0.25 Te using a dielectric-dependent hybrid density functional combined with spin–orbit coupling. Characterizing these point defects is essential as they are responsible for intrinsic doping and nonradiative recombination centers in the detector material. The dielectric-dependent hybrid functional allows for an accurate description of the bandgap (E g) for Hg 1 − x Cd x Te (MCT) over the entire compositional range, a level of accuracy challenging with standard hybrid functionals. Our comprehensive examination of the native point defects confirms that cation vacancies V Hg (Cd) are the primary sources of p -type conductivity in the LWIR material given their low defect formation energies and the presence of a shallow acceptor level (− /0) near the valence-band maximum. In addition to the shallow acceptor level, the cation vacancies exhibit a deep charge transition level (2 − / −) situated near the midgap, characteristic of nonradiative recombination centers. Our results indicate that Hg interstitial could also be a deep center in the LWIR MCT through a metastable configuration under the Hg-rich growth conditions. While an isolated Te antisite does not show deep levels, the formation of V Hg –Te Hg defect complex introduces a deep acceptor level within the bandgap. [ABSTRACT FROM AUTHOR]

Near-surface layers of the mercury chalcogenide (HgSe and n-HgTe) single crystals with the electron concentration in the range of 7 × 1014–4.2 × 1018 сm−3 were studied using the laser pump-probe thermoreflectance (TR) technique combined with the Fabry–Perot (FP) interferometer in the wide temperature interval of 10–300= K. The TR–FP measurements were carried out toward samples with a freshly etched reflective surface. As a result, a minimum in the time dependence of the TR–FP signal and sign inversion of the TR–FP signal were revealed both for HgSe and n-HgTe within the specified temperature range. Noticeably, both anomalies were observed for n-HgTe at substantially lower temperatures than that for HgSe. The proposed qualitative interpretation of the observed anomalies is based on the hypothesis of two types of Weyl nodes located in the Brillouin zone of mercury chalcogenides involving specific for the Weyl semimetals energy barriers, separating the bulk Weyl fermion helical states from the topologically protected Fermi-arc surface states. [ABSTRACT FROM AUTHOR]

Methodologies for identifying atmospheric oxidized mercury (HgII) compounds, including particulate-bound HgII (HgII(p)) and gaseous oxidized mercury (HgII(g)), by mass spectrometry (MS) are currently under development. This method requires preconcentration of HgII for analysis due to high instrument detection limits relative to ambient HgII concentrations. The objective of this work was to identify and test materials for quantitative capture of HgII from the gas phase, and to suggest potential surfaces onto which HgII can be collected, thermally desorbed, and characterized using MS methods. From the literature, several compounds were identified as potential sorbent materials and tested in the laboratory for uptake of gaseous elemental mercury (Hg0) and HgII(g)(permeated from a HgBr2 salt source). Chitosan, α-Al2O3, and γ-Al2O3 demonstrated HgII(g) capture in ambient air laboratory tests, without sorbing Hg0 under the same conditions. When compared to cation exchange membranes (CEM), chitosan captured a comparable quantity of HgII(g), while ≤ 90 % of loaded HgII(g) was recovered from α-Al2O3, and γ-Al2O3. When deployed in the field, the capture efficiency of chitosan decreased compared to CEM, indicating environmental conditions impacted the sorption efficiency of this material. The poor recovery of HgII from the tested materials compared to CEM in the field indicate that further identification and exploration of alternative sorbent materials is required to advance atmospheric mercury chemistry analysis by MS methods. [ABSTRACT FROM AUTHOR]

Skin whitening is a practice that is used to obtain lighter skin tone and is most prevalent in Africa and Asia. Substances used for this procedure, such as hydroquinone or mercury have a variety of side effects and are banned in several countries. This study examined the popularity of internet searches for terms related to skin whitening and bleaching creams with the use of GoogleTrends (GT). GT was searched globally for the topic “skin whitening” and two terms “hydroquinone cream” and “mercury cream” throughout a 10-year period (01.09.2013–31.08.2023). The popularity of searches increased during the analyzed period. The topic “skin whitening” was most popular in Sudan, Vietnam, and Sri Lanka. The searches were higher for “hydroquinone cream” than “mercury cream” in almost all countries, besides the Philippines and Indonesia. Our study confirms that skin whitening practices are popular, especially among populations with darker skin tone. Despite potentially toxic side effects, creams with hydroquinone and mercury are increasingly searched worldwide. Education about skin whitening and the usage of bleaching substances should be implemented, especially in the regions of Africa and Asia. [ABSTRACT FROM AUTHOR]

Soil contamination by toxic metals threatens global public health, highlighting the need for cost-effective and ecologically sound site remediation. In this study, we assessed phytoremediation of Hg-contaminated soils by Emilia fosbergii Nicolson (Asteraceae). Pot experiment was conducted using a substrate of sand and vermiculite (1:1 volume ratio), treatments consisted of five Hg concentrations (0, 1, 3, 5, and 7 mg kg−1). Metal transfer rates were calculated, including accumulation (BAF), translocation (TF) and bioconcentration (BCF) factors. E. fosbergii roots exhibited greater Hg accumulation than other tissues, but biomass production and plant health were not significantly affected at the concentrations tested, as indicated by elongation factors and tolerance index. The results revealed BAF values between 2.18 and 7.14, TF values ranged between 0.15 and 0.52, and the BCF index varied between 8.97 and 26.58. Treatments with Hg content of 5 mg kg−1 and 7 mg kg−1 recorded the highest total Hg concentrations of 66 mg kg−1 and 65.53 mg kg−1 (roots), and 9.18 mg kg−1 and 33.88 mg kg−1 (aerial), respectively. E. fosbergii demonstrated promise for Hg phytoremediation due to its high accumulation capacity, indicated by regular TF and high BCF and BAF indexes, thus classifying it as a high Hg accumulator. Phytoextractor and phytostabilizer plant, high accumulator of Hg. Weed with great capacity for proliferation and adaptability. E. fosbergii showed tolerance to Hg in the substrate. Promising plant for phytoremediation of soils contaminated by Hg. Novel species for recovery of soils degraded by Hg exposure. [ABSTRACT FROM AUTHOR]

Magnetic MnFe2O4 nanoparticles were successfully prepared by the rapid combustion method at 500 °C for 2 h with 30 mL absolute ethanol, and were characterized by SEM, TEM, XRD, VSM, and XPS techniques, their average particle size and the saturation magnetization were about 25.3 nm and 79.53 A·m2/kg, respectively. The magnetic MnFe2O4 nanoparticles were employed in a fixed bed experimental system to investigate the adsorption capacity of Hg0 from air. The MnFe2O4 nanoparticles exhibited the large adsorption performance on Hg0 with the adsorption capacity of 16.27 μg/g at the adsorption temperature of 50 °C with the space velocity of 4.8×104 h-1. The VSM and EDS results illustrated that the prepared MnFe2O4 nanoparticles were stable before and after adsorption and successfully adsorbed Hg0. The TG curves demonstrated that the mercury compound formed after adsorption was HgO, and both physical and chemical adsorption processes were observed. Magnetic MnFe2O4 nanoparticles revealed excellent adsorbance of Hg0 in air, which suggested that MnFe2O4 nanoparticles be promising for the removal of Hg0. [ABSTRACT FROM AUTHOR]

The fabrication of environmentally friendly materials for wastewater remediation represents a promising approach. Thus, we present the fabrication of nanostructured CoFe2O4 (CF) particles entangled within a hydrogel-based matrix composed of carboxy methyl cellulose-psyllium-RGO (CPRHG/CF). The functionality, composition, and nature of the fabricated composite were characterized using FTIR, XRD, and XPS techniques. Furthermore, the internal and surface morphology was analyzed through FE-SEM and HR-TEM imaging. To assess the photo activity, UV-Vis and photoluminescence (PL) spectroscopy were employed, confirming that CPRHG/CF exhibits significant potential for light absorption in the visible spectrum while minimizing the charge recombination rate. The fabricated CPR/CFHG composite hydrogel was employed for the removal of pharmaceutical effluent, tramadol (TMD), via both adsorption and photocatalysis processes. In batch adsorption experiments lasting 2 hours, the composite hydrogel demonstrated impressive adsorption efficiency of 92.93% and a maximum adsorption capacity of 89.97 mg g-1. Subsequently, during photocatalytic treatment under 1 h of solar illumination, approximately 90.36% of the TMD was successfully degraded. The degradation process followed a pseudo-firstorder kinetics model with a rate constant (k1) of 0.0380 min-1. Furthermore, the investigation of reactive oxygen species (ROS) has identified superoxide radicals (O2 -) as the major species responsible for the degradation process, which was confirmed through radical scavenging experiments. [ABSTRACT FROM AUTHOR]

Fe–Mn oxide modified biochar (FMBC) was produced to explore its potential for remediation of Hg–Cd contaminated paddy soils. The results showed that the application of FMBC decreased the contents of bioavailable Hg and Cd by 41.49–81.85% and 19.47–33.02% in contrast to CK, while the amount of labile organic carbon (C) fractions and C-pool management index (CPMI) was increased under BC and FMBC treated soils, indicating the enhancement of soil C storage and nutrient cycling function. Dry weight of different parts of Oryza sativa L. was enhanced after the addition of BC and FMBC, and the contents of Fe and Mn in root iron–manganese plaques (IMP) were 1.46–2.06 and 6.72–19.35 times higher than those of the control groups. Hg and Cd contents in brown rice under the FMBC treatments were significantly reduced by 18.32–71.16% and 59.52–72.11% compared with the control. FMBC addition altered the composition and metabolism function of soil bacterial communities, especially increasing the abundance of keystone phyla, including Firmicutes, Proteobacteria and Actinobacteria. Partial least squares path modelling (PLSPM) revealed that the contents of Na2S2O3–Hg, DTPA–Cd and IMP were the key indicators affecting Hg and Cd accumulation in rice grains. These results demonstrate the simultaneous value of FMBC in remediation of Hg and Cd combined pollution and restoring soil fertility and biological productivity. Highlights: FMBC effectively remediated Hg and Cd co-contaminated paddy soils. FMBC increased soil labile C fractions and C sequestration. FMBC improved the relative abundance of specific phyla and metabolism potential. PLSPM exhibited the main ways of reducing Hg and Cd accumulation in rice grains. [ABSTRACT FROM AUTHOR]

Illegal gold mining causes mercury and trace metal contamination in many Colombian territories. The government has been requested by several ethnic communities to monitor and evaluate the state of mercury contamination in strategic ecosystems. The work aimed to evaluate mercury and trace metal contamination in a mining area located in Afro-descendant communities in the department of Cauca, Colombia. The study estimated the Hg content in different environmental compartments, such as soil, water, sediments, and trees. The level of trace metals in soil samples was assessed. It also estimated the human health risk associated with Hg from fish consumption. The concentration of T-Hg was measured using atomic absorption, and the trace element content was measured using inductively coupled plasma mass spectrometry (ICP-MS). Two out of three watersheds examined had a mean T-Hg concentration in water that exceeded the international standard limit of 2.0 µg/L set by the United States Environmental Protection Agency (USEPA). The Rattlesnake River had the highest mean concentration of T-Hg in sediments at 1.05 µg/g. The community of La Toma exceeded the maximum permissible value for T-Hg in soil. While T-Hg concentrations in C. macropomum were low at 0.02 µg/g, they were surprisingly high in Prochilodus sp. at 0.53 µg/g. F. luschnathiana trees had the highest T-Hg levels at 18.3 ± 2.3 ng/g. The soil samples analyzed showed levels of As (21.4 µg/g), Cr (148.5 µg/g), V (205.0 µg/g), and Zn (146.5 µg/g) that exceeded the maximum levels established internationally. The presence of mercury and trace elements in the communities indicates a potential risk to human and environmental health. [ABSTRACT FROM AUTHOR]

Mercury is one of the main components of fluorescent lamps. Considering the adverse effects of mercury on human health and the environment, recovery of mercury-containing fluorescent lamps is very important in developed countries. The glass parts of used fluorescent lamps are among the dangerous wastes whose mercury content should be reduced to the lowest possible level according to international standards. The aim of this research is to achieve a systematic approach to minimize the amount of mercury present in fluorescent lamp glass residues according to the European Commission EC95/2002 regulations. In order to extract mercury from glasses, glass pieces were washed with deionized water, using stirring to increase washing efficiency. In order to achieve the maximum amount of extraction, parameters such as ratio of glass to deionized water (S/L), stirring time, temperature and pH were changed. The results showed that, the highest mercury extraction rate is about 98% and in the conditions S/L = 0.1, stirring time of 12 h, temperature of 60 °C and pH 1, which is using a combination of HCl and H3PO4 acid 5% with a ratio of 1:4 has been obtained. The success of this method not only increases environmental sustainability, but also classifies the resulting glass waste as non-hazardous. [ABSTRACT FROM AUTHOR]

Heavy metals exist in the ecosystem both naturally and due to anthropogenic activities and as recalcitrant pollutants; they are non-biodegradable and cause acute and chronic diseases to human beings and many lifeforms. A statistical experimental approach was applied in this current study to optimize the detoxification of mercury [Hg(II)] from mono-component biosorption system by a novel hybrid granular activated carbon (biosorbent) prepared from maize plant residues. The analysis of variance by the application of central composite design shows that all the studied independent factors greatly influence Hg(II) removal efficiency and uptake capacity. The optimum experimental condition of 30 min contact time, 0.5 g/L biosorbent dosage, and 15 mg/L initial Hg(II) concentration were achieved after seeking 20 optimization solutions at 0.903 desirability. The optimum percentage removal and uptake capacity of Hg(II) at the optimal experimental setup was 96.7% and 10.8 mg/g, respectively. To confirm the quadratic models developed for the prediction of the responses as a function of the independent factors, confirmatory laboratory experiments were performed at the optimum condition. The results show that at the established best experimental condition, the optimum Hg(II) removal efficiency of 98.3% and uptake capacity of 11.2 mg/g were attained, which were within the prediction intervals indicating the suitability of the quadratic models in predicting future cases. The TEM and XRD analyses show that the Hg(II) ions were adsorbed by the biosorbent successfully and this suggests the potential and applicability of this novel biosorbent in treating water contaminants, especially heavy metals. [ABSTRACT FROM AUTHOR]

Simple Summary: Mercury is a persistent and toxic metal that can affect marine life. Bottlenose dolphins are particularly vulnerable to mercury accumulation and toxicity because they are top predators and often inhabit near-shore environments with elevated mercury concentrations. This research assessed mercury accumulation in the tissues of bottlenose dolphins that were stranded during two time periods, 2013–2015 (dolphins that were stranded at an unusually high rate; heavily infected with morbillivirus) and 2016–2021 (dolphins that were stranded at a normal rate). We hypothesized that the immunosuppressed individuals would have higher mercury concentrations. Tissue selenium accumulation was also measured, as selenium has been shown to reduce mercury toxicity. Differences in tissue mercury concentrations were not observed between the two time periods; however, the tissue mercury concentrations were higher in adults than juveniles. The selenium distribution in the bottlenose dolphins was significantly different between the two time periods. These results suggest that selenium may not have been as protective against mercury toxicity in the bottlenose dolphins that were stranded during the UME. Bottlenose dolphins (Tursiops truncatus) are long-lived marine mammals, upper-level predators, and they inhabit near-shore environments, which increases their exposure to pollution. Mercury is a ubiquitous and persistent metal pollutant that can bioaccumulate and biomagnify up the food chain. Dolphins are known to accumulate mercury, and limited research has shown that mercury exposure can weaken the immune system of dolphins. The objectives of this study were to assess the mercury concentrations in the tissues (muscle, small intestine, liver) of stranded bottlenose dolphins and to compare the tissue mercury levels in dolphins that were stranded during the 2013–2015 morbillivirus Unusual Mortality Event (UME; immunosuppressed individuals) with the levels of those that were stranded at a normal rate (2016–2021). Selenium has been shown to reduce mercury toxicity in many animals; therefore, tissue selenium concentration and the molar ratio of selenium to mercury were also assessed. The tissue mercury (muscle, liver) and selenium (liver) concentrations increased with the age of the dolphins, with the liver accumulating the highest concentrations. No sex differences were observed in the mercury and selenium concentrations. While differences in tissue mercury concentrations were not observed due to the UME, the selenium accumulation profiles were significantly different between the two time periods. These results suggest that selenium may not have been as protective against mercury toxicity in the bottlenose dolphins that were stranded during the UME, possibly due to infection with morbillivirus. [ABSTRACT FROM AUTHOR]

Soil plays a crucial role in human health through its impact on food and habitation. However, it often contains toxic heavy metals, with mercury being particularly hazardous when methylated. Currently, high-sensitivity, rapid detection of mercury is achievable only through electrochemical measurements. These measurements require pretreatment of the soil sample and the preparation of a calibration curve tailored to the sample's condition. In this study, we developed a method to determine the environmental standard value of mercury content in soil by significantly reducing the pretreatment process. Our approach involves analyzing current peaks from electrodeposition times using specific electrodes and solvent settings. This method demonstrates low error rates under low concentration conditions and can detect mercury levels as low as 0.5 ppb in soil leachate and reagent dilution series. This research facilitates the determination of low mercury concentrations in solutions containing various soil micro-compounds without the need for calibration curves. [ABSTRACT FROM AUTHOR]

Historians have thoroughly documented the development of mercury-based silver refining in Spanish America in the late sixteenth century, and its use for over 300 years on an industrial scale unknown in Europe. However, we currently lack any consensus about the significance of this technology in the global history of knowledge. This article critically reassesses the invention and improvement of this refining method with the aim of addressing two interrelated issues. Firstly, how experiential knowledge and practical skills in silver refining were deliberately harnessed to solve a specific technical problem. Secondly, how economic incentives and patronage set the stage for empirical practices and a collaborative culture that facilitated the widespread use of this novel technique. In so doing, this article places silver refining within the theoretical constructs and historiography of useful knowledge, and bridges narratives that have remained largely isolated. [ABSTRACT FROM AUTHOR]

A new ZnII coordination polymer (CP) based on 2,3‐pyrazine dicarboxylic acid (H2pzdc) and 4,4′‐bipyridine (bpy) (ZCP) was synthesized using a facile slow evaporation method. Single‐crystal X‐ray diffraction revealed that ZCP is a two‐dimensional porous CP, [Zn2(pzdc)2(bpy)(H2O)2]n, with van der Waals forces as the dominant interaction within its layers forming a 63 network. Employing energetic ultrasound irradiation, nanoscale ZCP (nZCP) was successfully synthesized and Eu3+ ions were incorporated within its host lattice (Eu@nZCP). The resulting platform exhibits superior fluorescence characteristics and demonstrates notable optical durability. Therefore, it was used as a dual detection fluorescent sensing platform for the detection of mercury and l‐cysteine (l‐Cys) in aqueous media through a turn‐off/on strategy. In the turn‐off process, the fluorescence emission of Eu@nZCP progressively quenches by the addition of HgIIvia a photo‐induced electron transfer (PET) mechanism. The fluorescence of Eu@nZCP is quenched to establish a low fluorescence background through the incorporation of HgII. This devised turn‐on fluorescent system is suitable for the recognition of l‐Cys (based on the strong affinity of l‐Cys to the HgII ion) through a quencher detachment mechanism. This method attained a relatively wide linear range, spanning from 0.001 to 25 µM, with the low detection limit of 5 nM for the sensing of HgII. Also, the corresponding limit of detection (LOD) for l‐Cys is 8 nM in a relatively wide linear range, spanning from 0.001 to 40 µM. [ABSTRACT FROM AUTHOR]

The consumption of camel milk is gaining popularity in Algeria. This study aimed to determine the concentrations of Lead (Pb), Cadmium (Cd), Nickel (Ni) and Mercury (Hg) in camel milk sold in Southeast Algeria and assess the potential health risks associated with its consumption. 120 samples of camel milk were collected from 10 farms located near the roads in the south of Algeria. Metals were measured using an atomic absorption spectrophotometer with a graphite furnace and Target Hazard Quotients (THQs) were calculated. The mean concentrations were 0.026 ± 0.013 mg/kg, 0.001 ± 0.0002 mg/kg, 0.017 ± 0.002 mg/kg and 0.0005 ± 0.0002 mg/kg for Pb, Cd, Ni and Hg. The THQ was higher for children, suggesting health risks associated with consumption of camel milk for this age group (p <.001). The primary contribution of this study is the establishment of a database on toxic metal levels in camel milk, which can be valuable to manage possible risk associated with metals in milk. [ABSTRACT FROM AUTHOR]

The subcontinental lithospheric mantle (SCLM) is now suggested by many workers to play a role in the formation of orogenic gold deposits in active continental margins, given that the gold and volatiles may be introduced into the SCLM during plate subduction. The giant Cretaceous Jiaodong gold province within the North China block occurs in a convergent margin setting where there is no terrane accretion, thus eliminating from consideration the commonly accepted metal and fluid source reservoir for orogenic gold--the metamorphosed upper crust of an active orogenic belt. Thus, the auriferous fluids were released below the high-grade Archean cratonic rocks from either enriched SCLM or directly from the subducted oceanic slab. Mercury (Hg) isotopes allow fingerprinting of isotopically distinct reservoirs, discriminating between the two possibilities. We present Hg isotope data for a set of pyrite grains, native gold, and lamprophyres from six main gold districts in the Jiaodong gold province. These samples dominantly yielded near-zero Δ199Hg (0‰ ± 0.1‰), within uncertainty of the mantle Δ199Hg value. The results provide novel evidence that the SCLM predominantly controlled the Hg budget of the Jiaodong gold deposits, implying that the SCLM acted as a buffer for the crustal mass-independent fractionation Hg signatures and a storage reservoir for gold and volatiles. Consequently, during slab subduction, gold and volatiles were recycled and stored within the SCLM and were later released from the mantle during uplift and relaxation of compressional tectonics. [ABSTRACT FROM AUTHOR]

A new strategy for determining the Hg isotopes in low Hg concentration samples is proposed, utilizing the flow injection plasma electrochemical vapor generation (FI-PEVG) sampling technique coupled with MC-ICPMS. Our study reveals that PEVG technology not only offers superior sensitivity compared to that achieved by conventional cold vapor generation (CVG), but also reduces potential interferences/contaminations arising from reagents as it avoids the use of SnCl2, thus greatly facilitating the analysis of low content samples. By integrating with the FI technique, we can decrease the required sample volume to 0.15 mL (1.5 ng) and shorten the analysis time to just 150 s, resulting in significant reductions in sample consumption and analysis time. Different parameters affecting Hg isotope measurements were optimized, and the linear regression slope method was selected to process the transient Hg isotope signals. Under the optimized conditions, the δ202Hg and Δ199Hg values achieved a precision of 0.05‰ and 0.04‰ (SD, n = 33), respectively. The efficacy of our strategy is demonstrated by analyzing spiked natural water samples and two reference materials (GBW 08617 and GBW(E) 080124). Although a small number of low Hg concentration samples have been analyzed in this study, it is believed that the proposed method provides a promising rapid and sensitive approach for accurate Hg isotope analysis of low-content samples. [ABSTRACT FROM AUTHOR]

Methylmercury (MeHg), an environmental pollutant, is a ubiquitous neurotoxicant that ultimately leads to neurodegenerative diseases. New experimental models are needed for public health toxicity testing associated with this pollutant. In this study, a human pluripotent stem cell‐based brain‐on‐a‐chip, named Communicative Astrocyte–Neuron DYnamics chip (CANDY chip), is reported, which enables observation of the interactions of neurons with astrocytes and accurate assessment of responses to penetration of MeHg across the blood‐brain barrier. Five neurophysiological characteristics of the CANDY chip provide an exact emulation of the brain: i) co‐culture of neurons with astrocytes, ii) transport of nutrients from blood vessels to neurons via astrocytes, iii) glia‐to‐neurons ratio of 1:1, iv) low‐speed flow of brain interstitial fluid, and v) neuroprotection by astrocytes against MeHg‐induced toxicity. The remarkable vulnerability of neurons is identified to MeHg toxicity as shattered neurites and verifies the tolerance of astrocytes to MeHg toxicity despite morphological changes such as cell shrinkage. It is also confirmed that the chip faithfully recapitulates actual neurophysiological responses through high neuronal cell viability because of the astrocytes and increased brain‐derived neurotrophic factor as a neuroprotector. The CANDY chip can be a powerful platform for accurate neurotoxicity testing and modeling of complex neurodegenerative diseases. [ABSTRACT FROM AUTHOR]

Pore‐throat structure is a key factor that influences the storage and fluid flow capacity of tight sandstone reservoirs. Taking the tight sandstone reservoir of Xu2 Fm in Zhongba area as an example, the reservoir quality, pore‐throat type and pore size distribution of tight sandstone in the study area were described by casting thin section, scanning electron microscope and high‐pressure mercury injection test. In order to quantitatively characterize the complexity and heterogeneity of pore‐throat structure, fractal analysis was performed using mercury saturation and pore size data. This study mainly reveals the relationship between the geometric shape characteristics and fractal dimension of the binary pore structure of ultra‐low permeability tight sandstone and clarifies the influence of different scale pore throats on reservoir physical properties. The results indicate that the physical properties of the reservoir in the study area are poor, the pores are mainly intergranular pores and dissolution pores, the throat is flake and necked and the pore size distribution range is large. The fractal curve obtained by the mercury saturation method shows a significant turning point, and the pore‐throat system is divided into two types: small‐scale and large‐scale. The fractal dimension of large‐scale pore throat is greater than the three‐dimensional Euclidean space dimension, which does not conform to the fractal theory. The fractal dimension of small‐scale pore throat is closely related to the pore‐throat structure and has obvious fractal characteristics. The geometric shape of binary pore‐throat structure in tight sandstone is the main factor affecting the difference of fractal dimension. The development of small pores in sandstone is positively correlated with the total porosity, but its contribution to permeability is relatively low. The physical properties of tight sandstone are mainly controlled by the development degree of large‐scale pore throat. [ABSTRACT FROM AUTHOR]

Birds are used as bioindicators of environmental mercury (Hg) contamination, and toxicity reference values are needed for injury assessments. We conducted a comprehensive review, summarized data from 168 studies, performed a series of Bayesian hierarchical meta‐analyses, and developed new toxicity reference values for the effects of methylmercury (MeHg) on birds using a benchmark dose analysis framework. Lethal and sublethal effects of MeHg on birds were categorized into nine biologically relevant endpoint categories and three age classes. Effective Hg concentrations where there was a 10% reduction (EC10) in the production of juvenile offspring (0.55 µg/g wet wt adult blood‐equivalent Hg concentrations, 80% credible interval: [0.33, 0.85]), histology endpoints (0.49 [0.15, 0.96] and 0.61 [0.09, 2.48]), and biochemical markers (0.77 [<0.25, 2.12] and 0.57 [0.35, 0.92]) were substantially lower than those for survival (2.97 [2.10, 4.73] and 5.24 [3.30, 9.55]) and behavior (6.23 [1.84, >13.42] and 3.11 [2.10, 4.64]) of juveniles and adults, respectively. Within the egg age class, survival was the most sensitive endpoint (EC10 = 2.02 µg/g wet wt adult blood‐equivalent Hg concentrations [1.39, 2.94] or 1.17 µg/g fresh wet wt egg‐equivalent Hg concentrations [0.80, 1.70]). Body morphology was not particularly sensitive to Hg. We developed toxicity reference values using a combined survival and reproduction endpoints category for juveniles, because juveniles were more sensitive to Hg toxicity than eggs or adults. Adult blood‐equivalent Hg concentrations (µg/g wet wt) and egg‐equivalent Hg concentrations (µg/g fresh wet wt) caused low injury to birds (EC1) at 0.09 [0.04, 0.17] and 0.04 [0.01, 0.08], moderate injury (EC5) at 0.6 [0.37, 0.84] and 0.3 [0.17, 0.44], high injury (EC10) at 1.3 [0.94, 1.89] and 0.7 [0.49, 1.02], and severe injury (EC20) at 3.2 [2.24, 4.78] and 1.8 [1.28, 2.79], respectively. Maternal dietary Hg (µg/g dry wt) caused low injury to juveniles at 0.16 [0.05, 0.38], moderate injury at 0.6 [0.29, 1.03], high injury at 1.1 [0.63, 1.87], and severe injury at 2.4 [1.42, 4.13]. We found few substantial differences in Hg toxicity among avian taxonomic orders, including for controlled laboratory studies that injected Hg into eggs. Our results can be used to quantify injury to birds caused by Hg pollution. Environ Toxicol Chem 2024;43:1195–1241. Published 2024. This article is a U.S. Government work and is in the public domain in the USA. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. [ABSTRACT FROM AUTHOR]

A number of environmental toxicants are noted for their activity that leads to declined motor function. However, the role of muscle as a proximal toxicity target organ for environmental agents has received considerably less attention than the toxicity targets in the nervous system. Nonetheless, the effects of conventional neurotoxicants on processes of myogenesis and muscle maintenance are beginning to resolve a concerted role of muscle as a susceptible toxicity target. A large body of evidence from epidemiological, animal, and in vitro studies has established that methylmercury (MeHg) is a potent developmental toxicant, with the nervous system being a preferred target. Despite its well-recognized status as a neurotoxicant, there is accumulating evidence that MeHg also targets muscle and neuromuscular development as well as contributes to the etiology of motor defects with prenatal MeHg exposure. Here, we summarize evidence for targets of MeHg in the morphogenesis and maintenance of skeletal muscle that reveal effects on MeHg distribution, myogenesis, myotube formation, myotendinous junction formation, neuromuscular junction formation, and satellite cell-mediated muscle repair. We briefly recapitulate the molecular and cellular mechanisms of skeletal muscle development and highlight the pragmatic role of alternative model organisms, Drosophila and zebrafish, in delineating the molecular underpinnings of muscle development and MeHg-mediated myotoxicity. Finally, we discuss how toxicity targets in muscle development may inform the developmental origins of health and disease theory to explain the etiology of environmentally induced adult motor deficits and accelerated decline in muscle fitness with aging. [ABSTRACT FROM AUTHOR]

Background: Since the 1960's, mercury (Hg) contamination of the aquatic environment of Asubpeeschoseewagong Anishinabek (Grassy Narrows First Nation) territories has impacted the community members' traditions, culture, livelihood, diet and health. Despite decreasing Hg exposure over time, a recent study suggested that long-term exposure contributed to later-life symptom clusters of nervous system dysfunction. Here, the objective was to evaluate, 5 years later, the prevalence and progression of these symptoms and examine the contribution of long-term, past Hg exposure. Methods: The symptom questionnaire, applied in the 2016/17 Grassy Narrows Community Health Assessment (GN-CHA) (Time 1), was re-administered in the 2021/22 Niibin study (Time 2). A total of 85 adults (median age: 47y; range: 29-75y) responded at both times. Paired statistics were used to test the differences (Time 2 – Time 1) in self-reported symptom frequencies. The symptom clustering algorithm, derived from the entire study group of the GN-CHA (n = 391), which had yielded 6 clusters, was applied at Time 1 and 2. Equivalent hair Hg measurements (HHg) between 1970 and 1997 were used in Longitudinal Mixed Effects Models (LMEM), with a sub-group with ≥ 10 repeated HHg mesurements (age > 40y), to examine its associations with symptom cluster scores and their progression. Results: For most symptoms, paired analyses (Time 2 – Time 1) showed a significant increase in persons reporting " very often" or "all the time", and in the mean Likert scores for younger and older participants (< and ≥ 50y). The increase in cluster scores was not associated with age or sex, except for sensory impairment where a greater increase in symptom frequency was observed for younger persons. LMEM showed that, for the sub-group, long-term past Hg exposure was associated with most cluster scores at both times, and importantly, for all clusters, with their rate of increase over time (Time 2 – Time 1). Conclusions: The persistence of reported symptoms and their increase in frequency over the short 5-year period underline the need for adequate health care services. Results of the sub-group of persons > 40y, whose HHg reflects exposure over the 28-year sampling period, suggest that there may be a progressive impact of Hg on nervous system dysfunction. [ABSTRACT FROM AUTHOR]

The Multi-Compartment Hg (mercury) Modeling and Analysis Project (MCHgMAP) is an international multi-model research initiative intended to simulate and analyze the geospatial distributions and temporal trends of environmental Hg to inform the effectiveness evaluations of two multilateral environmental agreements (MEAs): the Minamata Convention on Mercury (MC) and Convention on Long-Range Transboundary Air Pollution (LRTAP). This MCHgMAP overview paper presents its science objectives, background and rationale, experimental design (multi-model ensemble (MME) architecture, inputs and evaluation data, simulations and reporting framework), and methodologies for the evaluation and analysis of simulated environmental Hg levels. The primary goals of the project are to facilitate detection and attribution of recent (observed) and future (projected) spatial patterns and temporal trends of global environmental Hg levels, and identification of key knowledge gaps in Hg science and modeling to improve future effectiveness evaluation cycles of the MEAs. The current advances and challenges of Hg models, emission inventories, and observational data are examined, and an optimized multi-model experimental design is introduced for addressing the key policy questions of the MEAs. A common set of emissions, environmental conditions, and observation datasets are proposed (where possible) to enhance the MME comparability. A novel harmonized simulation approach between atmospheric, land, oceanic and multi-media models is developed to account for the short- and long-term changes in secondary Hg exchanges and to achieve mechanistic consistency of Hg levels across environmental matrices. A comprehensive set of model experiments is developed and prioritized to ensure a systematic analysis and participation of a variety of models from the scientific community. [ABSTRACT FROM AUTHOR]

Mercury is notoriously difficult to form in Solar System simulations, due to its small mass and iron-rich composition. Smooth particle hydrodynamics simulations of collisions have found that a Mercury-like body could be formed by one or multiple giant impacts, but due to the chaotic nature of collisions, it is difficult to create a scenario where such impacts will take place. Recent work has found more success forming Mercury analogues by adding additional embryos near Mercury's orbit. In this work, we aim to form Mercury by simulating the formation of the Solar System in the presence of the giant planets Jupiter and Saturn. We test out the effect of an inner disk of embryos added on to the commonly used narrow annulus of initial material. We form Mercury analogues with core-mass fractions (CMFs) > 0.4 in ∼10% of our simulations, and twice that number of Mercury analogues form during the formation process but are unstable and do not last to the end of the simulations. Mercury analogues form at similar rates for both disks with and without an inner component, and most of our Mercury analogues have lower CMFs than that of Mercury, ∼0.7, due to significant accretion of debris material. We suggest that a more in-depth understanding of the fraction of debris mass that is lost to collisional grinding is necessary to understand Mercury's formation, or some additional mechanism is required to stop this debris from accreting. [ABSTRACT FROM AUTHOR]

Mercury (Hg) is a heterogeneously distributed toxicant affecting wildlife and human health. Yet, the spatial distribution of Hg remains poorly documented, especially in food webs, even though this knowledge is essential to assess large-scale risk of toxicity for the biota and human populations. Here, we used seabirds to assess, at an unprecedented population and geographic magnitude and high resolution, the spatial distribution of Hg in North Atlantic marine food webs. To this end, we combined tracking data of 837 seabirds from seven different species and 27 breeding colonies located across the North Atlantic and Atlantic Arctic together with Hg analyses in feathers representing individual seabird contamination based on their winter distribution. Our results highlight an east-west gradient in Hg concentrations with hot spots around southern Greenland and the east coast of Canada and a cold spot in the Barents and Kara Seas. We hypothesize that those gradients are influenced by eastern (Norwegian Atlantic Current and West Spitsbergen Current) and western (East Greenland Current) oceanic currents and melting of the Greenland Ice Sheet. By tracking spatial Hg contamination in marine ecosystems and through the identification of areas at risk of Hg toxicity, this study provides essential knowledge for international decisions about where the regulation of pollutants should be prioritized. [ABSTRACT FROM AUTHOR]

In order to study the gene expression of glutathione peroxidase (GPx) and glutathione-S-transferase (GST) in Ruditapes philippina- rum under the stress of heavy metal mercury (Hg), a single chronic exposure experiment on the indicator organism R. philippinarum was car- ried out. The expression of two genes in visceral mass and gill of R. philippinarum was detected at 0,12 h, 24 h and 2, 3, 4, 5, 6, 7 and 8 d. The results showed that the expression multiples of GPx and GST in the visceral mass showed a fluctuation trend, and the expression multiples reached the highest (P<0.05) at 24 and 12 h, respectively. The expression level was the lowest at 6 d(P>0.05) and 3 d (P<0.05). The ex- pression multiple of GPx in the gill was the highest at 8 d (P<0.05), and the first peak appeared at 5 d. The expression amount of GST was the highest at 5 d (P<0.05). It showed that mercury exposure could induce the expression of GPx and GST in different degrees in the short term, but it had obvious inhibitory effect with the extension of time. This study provided the theoretical basis for revealing the toxicity of heavy metal mercury to R. philippinarum. [ABSTRACT FROM AUTHOR]

Exposure to pollutants is a potentially crucial but overlooked driver of population declines in shorebirds along the East Asian-Australasian Flyway. We combined knowledge of moult strategy and life history with a standardised sampling protocol to assess mercury (Hg) contamination in 984 individuals across 33 migratory shorebird species on an intercontinental scale. Over one-third of the samples exceeded toxicity benchmarks. Feather Hg was best explained by moulting region, while habitat preference (coastal obligate vs. non-coastal obligate), the proportion of invertebrates in the diet and foraging stratum (foraging mostly on the surface vs. at depth) also contributed, but were less pronounced. Feather Hg was substantially higher in South China (Mai Po and Leizhou), Australia and the Yellow Sea than in temperate and Arctic breeding ranges. Non-coastal obligate species (Tringa genus) frequently encountered in freshwater habitats were at the highest risk. It is important to continue and expand biomonitoring research to assess how other pollutants might impact shorebirds. Over one-third of the sampled shorebirds along the East Asian-Australasian Flyway are facing Hg risk. Tringa genus in South China was at the highest risk. Feather Hg was best explained by feathers' moulting region, while habitat preference, diet, and foraging stratum were less important. [ABSTRACT FROM AUTHOR]

Geothermal fields emit remarkable amounts of mercury (Hg) to the environment. To address the source, fate and geochemical cycling of Hg in geothermal fields, we investigated Hg concentrations and isotopic compositions of hot spring water and fumarole gases from Rehai and Dagejia in SW‐China. Elevated Hg concentrations in fumarole gases (10.0–167 ng m−3) and hot spring water (3.44–84.5 ng L−1) were observed, suggesting that both geothermal fields are of environmental concern. The variation in Δ199Hg (−0.06 to 0.23‰) and Δ200Hg (−0.09 to 0.19‰) in hot spring water supports Hg likely originating from endogenous volcanic degassing and/or rainwater. Negative and nearly zero Δ199Hg in fumarole gases (−0.32 to 0.03‰) supports volcanic degassing and background atmosphere origin. The ranges of δ202Hg in fumarole gases (−0.74 to 0.59‰) and hot spring water (−1.29 to 0.52‰) could reflect limited fluids boiling in geothermal fields. This study, thus, fills an important knowledge gap regarding Hg global cycling. Plain Language Summary: A large amount of mercury (Hg) is emitted into the atmosphere through geothermal activities. A knowledge gap exists regarding the source, fate and geochemical cycling of Hg in geothermal fields. Here, we studied Hg concentrations and isotopic compositions in hot spring water and fumarole gases from two large geothermal fields in SW‐China. Our results support that the two fields received Hg from endogenous volcanic degassing and rainwater. Deep magma chambers acted as heat sources, triggering fluid circulation in geothermal areas and entraining Hg from rainwater into geothermal systems. Key Points: Rehai and Dagejia geothermal fields are likely of local environmental concern regarding Hg emissionMercury isotopic ratios evidence that geothermal fields could receive Hg from endogenous volcanic degassing and rainwaterGeothermal fluid boiling is not common in geothermal fields in SW‐China [ABSTRACT FROM AUTHOR]

During chemical looping combustion (CLC) and chemical looping gasification (CLG) of coal, the release, migration, and speciation of mercury in coal are significantly influenced by oxygen-carrier materials; however, the underlying mechanism remains inadequately addressed. In this work, the effect of a typical iron-based oxygen carrier on the release behavior of mercury from a bituminous coal and a lignite was investigated based on the Ontario-Hydro method. It is found that the effect of the iron-based oxygen carrier is attributed to three aspects: the enhanced release rate of mercury from coal, the adsorption of the released mercury, and the oxidization of gaseous Hg0 into Hg2+. With the increasing temperature, the adsorbance of mercury by the iron-based oxygen carrier decreases, while the oxidation of mercury enhances. Even at 900 °C, the adsorbance of mercury by the oxygen carrier remained at 0.1687 g/g, with a relative content of Hg2+ at 22.55%. Additionally, it was observed that iron-based oxygen carriers can physically absorb both Hg0 and Hg2+, while chemisorption refers to complex-compound formation between the iron-based oxygen carrier and mercury. [ABSTRACT FROM AUTHOR]

The protective effect of selenium (Se) against Hg-induced neurotoxicity has been widely investigated; however, the mechanisms behind this interaction have not been fully elucidated yet. In the current work, the role of Se against MeHg+-induced cytotoxicity in the human neuroblastoma cell line (SH-SY5Y) is reported for the first time by tracking Hg uptake and accumulation at the single-cell level by inductively coupled plasma-mass spectrometry in single-cell mode (SC-ICP-MS). The influence of different Se species (SeMet, SeMeSeCys, citrate-SeNPs, and chitosan-SeNPs) on MeHg+ cytotoxicity was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays. SeMet and SeMeSeCys exhibited protective effects against MeHg+-induced cell death, particularly at high MeHg+ concentrations (LC50). In addition, chitosan-SeNPs showed greater protection compared to citrate-SeNPs when co-exposed with MeHg+. Interestingly, SC-ICP-MS unveiled the heterogeneous distribution of Hg uptake by SH-SY5Y cells. Co-exposure of SeMet and SeMeSeCys with MeHg+ led to a reduction of the amount of Hg accumulated per individual cell, which decreased the maximum level of Hg per cell by half (from 60 fg Hg cell−1 to 30 fg Hg cell−1) when SeMet was present, along with a decrease in the percentage of cells that accumulated the highest quantity of MeHg+. All these data corroborate the protective role of Se against Hg toxicity at the cellular level. [ABSTRACT FROM AUTHOR]

This study aimed to analyse the concentrations of mercury in fish samples available in the Algerian market and evaluate the potential health risks associated with their consumption. A total of 135 fish samples, representing the species Sardina pilchardus, Merluccius merluccius, Sparus aurata and Auxis rochie, were collected and analysed. Mercury levels were determined using thermal decomposition amalgamation Atomic Absorption Spectrophotometry. Health risks were evaluated by calculating hazard quotients. The overall mean concentration was 0.19 ± 0.11 mg/kg across all species. Individual species concentrations were recorded as 0.17 ± 0.08 mg/kg for Sardina pilchardus, 0.26 ± 0.19 mg/kg for Merluccius merluccius, 0.27 ± 0.18 mg/kg for Sparus aurata and 0.23 ± 0.13 mg/kg for Auxis rochei. Hazard quotients were below 1, indicating low health risk for fish consumers. Nevertheless, it is recommended to conduct periodic monitoring of heavy metal levels in fish, coupled with ongoing risk assessments, to ensure continued consumer protection. [ABSTRACT FROM AUTHOR]

Sulfur polymers, prepared by inverse vulcanization using elemental sulfur and vinylic monomers, are emerging functional materials of current research interest; however, sulfur polymers suffer from limited water solubility due to the hydrophobic nature of conventional comonomers and sulfur. Herein, the preparation of ionic liquid (IL)‐containing sulfur polymers are reported using the hydrophilic ionic liquid, 1‐allyl‐3‐vinylimidazolium chloride (AVImCl) as a comonomer. The introduction of IL significantly enhances the hydrophilicity of sulfur polymers, enabling them to dissolve in water. Benefiting from the thorough contact with aqueous mercury ions, the resultant sulfur polymer possesses high uptake capacity (436 mg g−1). After binding mercury, a coordination complex is formed and precipitated. The charged sulfur polymers gain a new application in demulsification. The polymer quickly breaks oil‐in‐water (O/W) emulsions through anion exchange between Cl− of the polymer and dodecylbenzenesulfonate (DBS−) of the surfactant. In addition, the polymer has a growth inhibitory effect against Staphylococcus aureus. The integration of IL and elemental sulfur provides a novel approach to modifying the wettability of sulfur polymers. Also, this novel water‐soluble IL‐containing sulfur polymer, with mercury capture, demulsification, and antibacterial activity, can be considered as a multifunctional material in practical water purification. [ABSTRACT FROM AUTHOR]

In this paper, we report on the development of an 'off–on' fluorescent probe for the detection of hydrogen peroxide (H2O2) and mercury ions (Hg2+) using an in situ synthesized carbon quantum dot and gum Arabic silver nanoparticle composite (CQDs@GA-Ag NPs). Electron microscopy measurement clearly shows that CQDs are attached to the surface of the GA-Ag NPs. The fluorescence intensity of the CQDs was dramatically quenched in the synthesized nanocomposite via the inner filter effect (IFE) mechanism. After adding H2O2 to the nanocomposite system, the Ag NPs got oxidized leading to the formation of Ag+ ions, and the CQDs regained their photoluminescence (PL) property. This facilitates the detection of H2O2 with an extremely low detection limit of 1.02 μM. Furthermore, the as-developed nanocomposite was also tested for the detection of Hg2+ ions, obtaining a remarkably low detection limit of 1.82 μM. The developed probe was extremely selective over a wide range of interfering ions and substances. [ABSTRACT FROM AUTHOR]

The air–sea exchange of elemental mercury (Hg0) plays an important role in the global Hg cycle. Existing air–sea exchange models for Hg0 have not considered the impact of sea surfactants and wave breaking on the exchange velocity, leading to insufficient constraints on the flux of Hg0. In this study, we have improved the air–sea exchange model of Hg0 in the three-dimensional ocean transport model MITgcm by incorporating sea surfactants and wave breaking processes through parameterization utilizing the total organic carbon concentration and significant wave height data. The inclusion of these factors results in an increase of over twofold in the transfer velocity of Hg0 relative to the baseline model. Air–sea exchange flux is increased in mid- to high-latitude regions with high wind and wave breaking efficiency, while it is reduced by surfactant and concentration change at low latitudes with low wind speeds and nearshore areas with low wave heights. Compared with previous parameterizations, the updated model demonstrates a stronger dependence of Hg0 air–sea exchange velocity on wind speed. Our results also provide a theoretical explanation for the large variances in estimated transfer velocity between different schemes. [ABSTRACT FROM AUTHOR]

We studied δ13C, δ15N and δ18O values, and total mercury (THg) concentrations in muscle samples from deep-sea predators – five beaked whale species and sperm whales – stranded along the coast of Hokkaido, in the north of Japan in 2010 and 2019. The δ13C, δ15N and δ18O values, THg concentrations, and body length (BL) of Stejneger’s beaked whales were similar to those of Hubbs’ beaked whales, which belong to the same genus. In contrast, δ13C values, THg concentrations, and BL of Sato’s beaked whales were markedly different from those of Baird’s beaked whales, which belong to the same genus. Stejneger’s and Hubbs’ beaked whales living around Hokkaido may compete in their ecological niches, whereas Sato’s and Baird’s beaked whales may segregate their ecological niches. Although Cuvier’s beaked whales and sperm whales belong to different genera and their BLs were significantly different, their δ13C and δ15N values were similar, probably because they can dive and stay in deeper waters than other beaked whale species. The δ13C values in combined samples from all whales increased with increasing BL, probably owing to the larger whale species’ dietary preference for squid. The δ13C values in combined samples from all whales were positively correlated with THg concentrations, whereas the δ15N values in the combined samples were negatively correlated. The δ18O values in combined samples from most whales tended to be positively correlated with THg concentrations. These correlations may be explained by a higher THg load from deep-sea feeding than from pelagic feeding and by a feeding shift towards lower trophic levels. [ABSTRACT FROM AUTHOR]

Background and aims: Forest soil has numerous ecological functions, some of which are regulated by biogeochemical processes involving trace elements (TEs). However, the accumulation and transport of TEs in remote pure forest ecosystems have been poorly understood to date. Methods: We investigated the concentrations and pools of Cu, Zn, Cd, Pb, Ni, Cr, Hg, and As in the soil horizons of Qinghai spruce and Qilian juniper forests at various elevations in the central Qilian Mountains, northwest China. The Enrichment Factor and Biogeochemical Index were used to evaluate the ecological security of TEs in forest soils. Results: The results indicate that the distribution of TEs concentrations in soil horizons of the two forest stands had spatial heterogeneity and element specificity. The TEs pools in the soil horizons of these stands increased with increasing soil depth. Among the elements studied, the total pools of Zn and Cr in the soil of the two stands were the largest, while the Hg and Cd pools were the smallest. Results further demonstrated that the forest ecosystem in the Tianlaochi catchment had large TEs storage, which was higher in Qinghai spruce forest than in Qilian juniper forest. Conclusions: Forest soils with lower TEs concentrations have higher enrichment degrees and potential ecological risk. Our findings highlight the importance of TEs accumulation in forest soils and warrant more research on their cycling in the region. [ABSTRACT FROM AUTHOR]

Firefly luciferases emit yellow-green light and are pH-sensitive, changing the bioluminescence color to red in the presence of heavy metals, acidic pH and high temperatures. These pH and metal-sensitivities have been recently harnessed for intracellular pH indication and toxic metal biosensing. However, whereas the structure of the pH sensor and the metal binding site, which consists mainly of two salt bridges that close the active site (E311/R337 and H310/E354), has been identified, the specific role of residue H310 in pH and metal sensing is still under debate. The Amydetes vivianii firefly luciferase has one of the lowest pH sensitivities among the group of pH-sensitive firefly luciferases, displaying high bioluminescent activity and special spectral selectivity for cadmium and mercury, which makes it a promising analytical reagent. Using site-directed mutagenesis, we have investigated in detail the role of residue H310 on pH and metal sensitivity in this luciferase. Negatively charged residues at position 310 increase the pH sensitivity and metal sensitivity; H310G considerably increases the size of the cavity, severely impacting the activity, H310R closes the cavity, and H310F considerably decreases both pH and metal sensitivities. However, no substitution completely abolished pH and metal sensitivities. The results indicate that the presence of negatively charged and basic side chains at position 310 is important for pH sensitivity and metals coordination, but not essential, indicating that the remaining side chains of E311 and E354 may still coordinate some metals in this site. Furthermore, a metal binding site search predicted that H310 mutations decrease the affinity mainly for Zn, Ni and Hg but less for Cd, and revealed the possible existence of additional binding sites for Zn, Ni and Hg. [ABSTRACT FROM AUTHOR]

In this work, we employed L-methionine (L-M) as the functionalized reagent of AuNPs for the colorimetric and UV–vis dual-mode detection of As3+, Cd2+, and Hg2+ ions with excellent selectivity and anti-interference. After adding the target ions, the functionalized AuNPs can be cross-linked together due to the As3+/Cd2+/Hg2+ ions reacting with amino N, carbonyl or hydroxyl O of L-methionine to form the coordination bonds, resulting in the aggregation of functionalized AuNPs and cause the different red-shifts of the SPR absorption peak and color changes of functionalized AuNPs solutions. The LODs of the colorimetric sensor are 10 ppb/13 ppb/4 ppb by naked eyes and 2.35 ppb/1.68 ppb/0.32 ppb by UV–vis spectroscopy with good linear relationships between the absorbance ratios (A633nm/A519nm, A645nm/A519nm and A665nm/A519nm) and As3+, Cd2+ and Hg2+ concentrations, which can be successfully applied to sense and detect As3+/Cd2+/Hg2+ pollutants in tap water, pond water, well water, and other domestic water sources. [ABSTRACT FROM AUTHOR]

A series of Fe6Mn1Cux adsorbents for mercury removal were prepared by using co‐precipitation and impregnation methods. The performance of mercury adsorption and anti‐SO2 characteristic was studied in a fixed‐bed experimental system. The effect of Cu doping amount, reaction temperature, and flue gas components on mercury removal was investigated. The mercury species on the spent adsorbent was analyzed through Hg‐TPD test. The physical–chemical features were characterized by using the N2 adsorption/desorption, VSM, XPS, and XRD. It was found that the Fe6Mn1Cu0.4 exhibited a high performance of mercury adsorption and well magnetic property and good sulfur resistance. Under high concentration of SO2, the average adsorption efficiency of Fe6Mn1Cu0.4 adsorbent achieved 99%. Cu modification optimized the pore structure and improved the mercury removal performance as well as SO2 resistance. The XPS analysis indicated that Mn4+ was the main form that played an important role in oxidizing Hg0, as a result of decrement of Mn4+ after mercury adsorption. Mercury adsorbed on the spent adsorbent was HgO and HgSO4. [ABSTRACT FROM AUTHOR]

Exposure to certain chemicals prenatally and in childhood can impact development and may increase risk for attention-deficit/hyperactivity disorder (ADHD). Leveraging a larger set of literature searches conducted to synthesize results from longitudinal studies of potentially modifiable risk factors for childhood ADHD, we present meta-analytic results from 66 studies that examined the associations between early chemical exposures and later ADHD diagnosis or symptoms. Studies were eligible for inclusion if the chemical exposure occurred at least 6 months prior to measurement of ADHD diagnosis or symptomatology. Included papers were published between 1975 and 2019 on exposure to anesthetics (n = 5), cadmium (n = 3), hexachlorobenzene (n = 4), lead (n = 22), mercury (n = 12), organophosphates (n = 7), and polychlorinated biphenyls (n = 13). Analyses are presented for each chemical exposure by type of ADHD outcome reported (categorical vs. continuous), type of ADHD measurement (overall measures of ADHD, ADHD symptoms only, ADHD diagnosis only, inattention only, hyperactivity/impulsivity only), and timing of exposure (prenatal vs. childhood vs. cumulative), whenever at least 3 relevant effect sizes were available. Childhood lead exposure was positively associated with ADHD diagnosis and symptoms in all analyses except for the prenatal analyses (odds ratios (ORs) ranging from 1.60 to 2.62, correlation coefficients (CCs) ranging from 0.14 to 0.16). Other statistically significant associations were limited to organophosphates (CC = 0.11, 95% confidence interval (CI): 0.03–0.19 for continuous measures of ADHD outcomes overall), polychlorinated biphenyls (CC = 0.08, 95% CI: 0.02–0.14 for continuous measures of inattention as the outcome), and both prenatal and childhood mercury exposure (CC = 0.02, 95% CI: 0.00–0.04 for continuous measures of ADHD outcomes overall for either exposure window). Our findings provide further support for negative impacts of prenatal and/or childhood exposure to certain chemicals and raise the possibility that primary prevention and targeted screening could prevent or mitigate ADHD symptomatology. Furthermore, these findings support the need for regular review of regulations as our scientific understanding of the risks posed by these chemicals evolves. [ABSTRACT FROM AUTHOR]

This article reviews research on sediment flux impacts on the receiving estuary, ports, and society in Cartagena, Colombia. The city hosts both the country's largest touristic and coastal industrial sectors and is home to vulnerable coastal communities whose health and livelihoods are impacted by pollution. These marginalized artisanal fishing communities lack basic water and health services but have finally been recognized in a new intersectoral committee for Cartagena Bay's environmental management. To support the governance of these complex socioenvironmental challenges, the Cartagena Bay Observatory has been developed as a scientific tool to monitor the bay's conditions and forecast the effects of future sediment remediation plans. Cartagena Bay receives large freshwater discharges from the Dique Canal, draining from the 260,000 km2 Magdalena River watershed where 80% of the national population resides. This runoff transports sediment loads of 2.3 Mt/year, dispersing large plumes that affect the marine ecosystems and tourism and make the bay one of the Caribbean's largest sediment‐receiving estuaries. Following decades of watershed deforestation and erosion, the upward trending sediment inputs and accretion of the Dique delta have resulted in deposition rates of 1.8 cm/year, and the need for frequent dredging. Mercury dumped by a chemical industry in the 1970s can be found in concentrations as high as 18.8 μg/g buried below the bay's bottom. Mercury has also been found in the bay's biota and human populations, and so the dredging needed for the port's sustainability thereby presents a health risk by allowing this trapped mercury to surface. This article is categorized under:Science of Water > Hydrological ProcessesScience of Water > Water QualityScience of Water > Water and Environmental Change [ABSTRACT FROM AUTHOR]

Objectives: This study investigated the presence of mercury in commonly used over the counter skin-lightening creams available in Trinidad and Tobago. The objective of this study was to evaluate if skin-lightening creams commonly used in Trinidad and Tobago contained Mercury, and establish the health risks presented by these products. Methods: Nineteen skin-lightening creams were analysed using Cold Capor Atomic Absorption Spectrophotometry (CV-AAS). Margin of Safety (MoS) and Hazard Quotient (HQ) calculations were used to assess risk to users. Results: Of the nineteen creams assessed, sixteen contained high concentrations of mercury (0.294-14414.5 μg/g), only three creams had no mercury detected. 9 of the 19 samples contained levels of mercury that exceed the Minamata convention's accepted limit of 1μg/g, with 3 samples exceeding 3800.000 μg/g. Risk assessments using MoS and HQ showed that 3 of the samples were unsafe for use and are considered hazardous. The study also revealed that many creams do contain mercury even if it did not constitute part of the product formulation. Conclusion: The data infers that some manufacturers do add mercury to their formulations while others are the victims of contaminated raw materials. MoS and HQ show that 21% of the samples were unsafe and 16% can be considered hazardous for human use. It is possible that with such levels of mercury in these products and the popularity of these products within the Caribbean Community and its diaspora, that there exists a significant amount of members with higher than acceptable mercury levels, with undiagnosed clinical symptoms. [ABSTRACT FROM AUTHOR]

Methylmercury is an environmental polluting organometallic compound that exhibits neurotoxicity, as observed in Minamata disease patients. Methylmercury damages peripheral nerves in Minamata patients, causing more damage to sensory nerves than motor nerves. Peripheral nerves are composed of three cell types: dorsal root ganglion (DRG) cells, anterior horn cells (AHCs), and Schwann cells. In this study, we compared cultured these three cell types derived from the rat for susceptibility to methylmercury cytotoxicity, intracellular accumulation of mercury, expression of L-type amino acid transporter 1 (LAT1), which transports methylmercury into cells, and expression of multidrug resistanceassociated protein 2 (MRP2), which transports methylmercury-glutathione conjugates into the extracellular space. Of the cells examined, we found that DRG cells were the most susceptible to methylmercury with markedly higher intracellular accumulation of mercury. The constitutive level of LAT1 was higher and that of MRP2 lower in DRG cells compared with those in AHC and Schwann cells. Additionally, decreased cell viability caused by methylmercury was significantly reduced by either the LAT1 inhibitor, JPH203, or siRNA-mediated knockdown of LAT1. On the other hand, an MRP2 inhibitor, MK571, significantly intensified the decrease in the cell viability caused by methylmercury. Our results provide a cellular basis for sensory neve predominant injury in the peripheral nerves of Minamata disease patients. [ABSTRACT FROM AUTHOR]

Currently barrens communities only represent about 1% of their original area in the Great Lakes region. To maintain or restore barrens vegetation, prescribed fire is often applied to limit the regeneration of undesirable species and shrubs. Vegetation community response is a combination of direct fire effects on the vegetation vitality and the indirect effect of soil nitrogen (N) loss that favors nutrient‐poor adapted barren communities. In this study, we assessed forest floor and upper mineral soil (0–5 cm) pools of carbon (C), N, and mercury (Hg) before and after prescribed fire of the Moquah Barrens in northwest Wisconsin. Although we took measurements in four distinct cover types, we found no relationship between cover type and soil pools. Across all cover types, prescribed fire led to considerable emissions of C, N, and Hg in the forest floor but only Hg in the upper mineral soils (0–5 cm), presumably because maximum fire temperatures were met for Hg volatilization. We classified fire severity and soil surface temperatures at the quadrat scale, but no discernable relationships with emissions were observed. The lack of detectable relationships is likely the result of a mismatch between the scales of response variables and predictors. As a result, we calculated ecosystem‐scale fire emissions based on the total area burned because we could not discern other smaller scale predictors. Overall emissions from dormant, spring season prescribed fires at the Moquah Barrens were approximately 11,000 Mg (5.5 Mg ha−1) for C, 350 Mg for N (0.17 Mg ha−1), and 4,500 g for Hg (2.3 g ha−1). Core Ideas: Imperiled barrens communities only represent a small area of their original distribution.As a result of the decrease in barrens habitat, associated fauna and flora are also in decline.Prescribed fire is used to maintain or restore barrens ecosystems.Fire leads to the changes in soil carbon, nitrogen, and mercury pools and leads to associated emissions.Emissions from the Moquah Barrens prescribed fires were minor and did lead to the goal of decreasing soil nitrogen. [ABSTRACT FROM AUTHOR]

This paper investigates women's everyday reproductive struggles in contexts of toxic contamination and the tensions emerging between toxic exposure and care in women's experiences of motherhood. While scientific framings of reproductive disruptions understand social identities as pre‐existing the experience of toxic risks, in this paper I argue that, in toxic territories, the categories of “contaminating” and “contaminated” actors interact with other categories of identity, such as gender and race, shaping social relations. Drawing on 13 months of ethnographic fieldwork conducted in the Bajo Cauca region among gold mining and coca farming communities, I investigate the everyday processes of gendered subject formation that unfold in toxic territories and the emergence of “faulty” gendered identities for rural mothers. Building on scholarship in feminist geography and Latin American feminist science and technology studies, I argue that ineffective forms of integration of gender in the institutional debate on toxic contamination reproduce, rather than challenge, the invisibility of rural women before the state. [ABSTRACT FROM AUTHOR]

In this study, the primary objective is to synthesize a novel fluorescent Rh‐PP‐Rh compound and explore its extensive range of photochemical behaviors. Initially, the synthesis of the novel Rh‐PP‐Rh was carried out for this purpose. Subsequently, UV‐Vis and fluorescence spectroscopy were employed to investigate the interactions between Rh‐PP‐Rh and a diverse array of ions in aqueous solvent systems. Through fluorescence and UV‐Vis studies, it was observed that Rh‐PP‐Rh demonstrated turn‐on sensor properties in the presence of Hg2+ ions. Furthermore, the limits of detection (LOD) and association constant (Ka) values for Rh‐PP‐Rh/Hg2+ were determined as 334 nM and 9.13×1011 M−2, respectively. Additionally, the reversible studies demonstrated a switchable on/off response upon alternate addition of HgCl2 and [Bu4N]F to Rh‐PP‐Rh. These findings suggest that the probe Rh‐PP‐Rh also possesses specific sensor properties for F− ions in the presence of mercury. In addition, the investigation encompassed an assessment of the visual analysis of the color alterations of Rh‐PP‐Rh both on filter paper and in an EtOH/H2O solution. The findings demonstrated that Rh‐PP‐Rh can be successfully utilized in solutions containing mercury, as it generates significant color transformations. [ABSTRACT FROM AUTHOR]

Annually, a tremendous amount of mercury is emitted due to anthropogenic activities. As a consequence, occupational and environmental exposure to mercury has drawn broad concern all over the world, and attempts have been sustained to progress analytical methods. The main limitation in exposure assessment is the complexity of biological and environmental samples. Environmental and biological samples need sample preparation to eliminate matrix interferences as well as pre-concentration of the ultra-trace analyte. Among sample preparation methods, considerable attention is devoted to solid-phase extraction (SPE). Porous materials play a vital role in the solid phase extraction procedure for the adsorption and desorption of the target analytes. In this paper, porous materials that were applied for inorganic mercury solid phase extraction were reviewed from 2009 until 2023. Through this study, porous materials were classified and the extraction parameters of each analytical method, including the type of solid phase extraction, porous adsorbent, adsorbent amount, extraction efficiency, real matrices, and detection technique, were clarified. Ultimately, novel attitudes toward green analytical chemistry and innovative ideas were discussed in order to open new horizons. [ABSTRACT FROM AUTHOR]

In this project, a nanosorbent was prepared using graphene oxide nanosheets modified with a specific mercury aptamer to detect very low mercury concentrations in aqueous solutions. The properties of the prepared nanosheets as adsorbents in the adsorption of mercury cations by microextraction in a packed syringe and analysis with a spectrophotometer were evaluated. Scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray energy diffraction were used to characterize the nanosheets obtained. The optimization conditions affecting the extraction and determination of mercury by spectrophotometry such as the influence of the pH of the aqueous solution, the number of sample loading times, the number of desorption times, the contact time of the analyte with the adsorbent, the amount of adsorbent and the volume of wash solvent were investigated. Under optimization conditions, the calibration curve of the method was linear between 20 and 800 μg L−1, and the detection limit of the method was 2.2 μg L−1. Mercury analysis in real samples such as Gavoshan dam water, Gamasiab river water and Bashir Taq Bostan spring water was also investigated to evaluate the method. [ABSTRACT FROM AUTHOR]

Kawasaki disease (KD) is an acute systemic vasculitis primarily affecting young children, with an unclear etiology. We investigated the link between maternal heavy metal exposure and KD incidence in children using the Japan Environment and Children's Study, a large-scale nationwide prospective cohort with approximately 100,000 mother–child pairs. Maternal blood samples collected during the second/third trimester were analyzed for heavy metals [mercury (Hg), cadmium (Cd), lead (Pb), selenium (Se), manganese (Mn)], divided into four quartiles based on concentration levels. KD incidence within the first year of life was tracked via questionnaire. Among 85,378 mother–child pairs, 316 children (0.37%) under one year were diagnosed with KD. Compared with the lowest concentration group (Q1), the highest (Q4) showed odds ratios (95% confidence interval) for Hg, 1.29 (0.82–2.03); Cd, 0.99 (0.63–1.58); Pb, 0.84 (0.52–1.34); Se, 1.17 (0.70–1.94); Mn, 0.70 (0.44–1.11), indicating no concentration-dependent increase. Sensitivity analyses with logarithmic transformation and extended outcomes up to age 3 yielded similar results. No significant association was found between maternal heavy metal levels and KD incidence, suggesting that heavy metal exposure does not increase KD risk. [ABSTRACT FROM AUTHOR]