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Mercury, particularly in its methylated form, poses a significant environmental and health risk in aquatic ecosystems. While the toxicity and bioaccumulation of mercury are well documented, there remains a critical gap in our understanding of the mechanisms governing mercury methylation and demethylation in aquatic environments. This review systematically examines the complex interplay of chemical, biological, and physical factors that influence mercury speciation and transformation in natural water systems. We provide a comprehensive analysis of methylation and demethylation processes, specifically focusing on the dominant role of methanogenic bacteria. Our study highlights the crucial function of hgcAB genes in facilitating mercury methylation by anaerobic microorganisms, an area that represents a frontier in current research. By synthesizing the existing knowledge and identifying key research priorities, this review offers novel insights into the intricate dynamics of mercury cycling in aquatic ecosystems. Our findings provide a theoretical framework to inform future studies and guide pollution management strategies for mercury and its compounds in aquatic environments. [ABSTRACT FROM AUTHOR]

The dimeric β‐diketiminato calcium hydride, [(DippBDI)CaH]2 (DippBDI = HC{(Me)CN‐2,6‐i‐Pr2C6H3}2), reacts with ortho‐, meta‐ or para‐tolyl mercuric compounds to afford hydridoarylcalcium compounds, [(DippBDI)2Ca2(μ‐H)(μ‐o‐,m‐,p‐tolyl)], in which dimer propagation occurs either via μ2‐η1‐η1 or μ2‐η1‐η6 bridging between the calcium centers. In each case, the orientation and hapticity of the aryl units is dependent upon the position of the methyl substituent. While wholly organometallic meta‐ and para‐tolyl dimers, [(DippBDI)Ca(m‐tolyl)]2 and [(DippBDI)Ca(p‐tolyl)]2, can be prepared and are stable, the ortho‐tolyl isomer is prone to isomerization to a calcium benzyl analog. Computational analysis of this latter process with density functional theory (DFT) highlights an unusual mechanism invoking the generation of an intermediate dicalcium species in which the group 2 centers are bridged by a toluene dianion formed by the formal attachment of the original hydride anion to the initially generated ortho‐tolyl substituent. Use of a more sterically encumbered aryl substituent, {3,5‐t‐Bu2C6H3}, facilitates the selective formation of [(DippBDI)Ca(μ‐H)(μ‐3,5‐t‐Bu2C6H3)Ca(DippBDI)], which can be converted into the unsymmetrically‐substituted σ‐aryl calcium complexes, [(DippBDI)Ca(μ‐Ph)(μ‐3,5‐t‐Bu2C6H3)Ca(DippBDI)] and [(DippBDI)Ca(μ‐p‐tolyl)(μ‐3,5‐t‐Bu2C6H3)Ca(DippBDI)] by reaction with the appropriate mercuric diaryl. Conversion of [(DippBDI)Ca(H)(Ph)Ca(DippBDI)] to afford [{{(DippBDI)Ca}2(μ2‐Cl)}2(C6H5‐C6H5)], comprising a biphenyl dianion, is also reported. Although this latter transformation is serendipitous, AIM analysis highlights that, in a related manner to the ortho‐tolyl to benzyl isomerization, the requisite C–C coupling may be facilitated in an "across dimer" fashion by the experimentally‐observed polyhapto engagement of the aryl substituents with each calcium. [ABSTRACT FROM AUTHOR]

There is much uncertainty regarding the sources of reactive mercury (RM) compounds and atmospheric chemistry driving their formation. Thiswork focused on assessing the chemistry and potential sources of reactive mercury measured in Reno, Nevada, United States, using 1 year of data collected using Reactive Mercury Active System. In addition, ancillary meteorology and criteria air pollutant data, Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) analyses, and a generalized linear model were applied to better understand reactive mercury observations. During the year of sampling, a fire event impacted the sampling site, and gaseous elemental Hg and particulate-bound mercury concentrations increased, as did HgII-S compounds. Data collected on a peak above Reno showed that reactive mercury concentrations were higher at higher elevation, and compounds found in Reno were the same as those measured on the peak. HYSPLIT results demonstratedRMcompounds were generated inside and outside of the basin housing Reno. Compounds were sourced from San Francisco, Sacramento, and Reno in the fall and winter, and from long-range transport and the marine boundary layer during the spring and summer. The generalized linear model produced correlations that could be explained; however, when applying the model to similar data collected at two other locations, the Reno model did not predict the observations, suggesting that sampling location chemistry and concentration cannot be generalized. [ABSTRACT FROM AUTHOR]

Objective The aim is to clarify the speciation and thermo-release characteristics of mercury in failure mercury adsorbent for natural gas containing metal sulfides. Method The temperature programmed thermal release mercury experimental of mercury compound reference material, elemental mercury and failure mercury adsorbent were carried out in air atmosphere. Results The thermal release peaks of different mercury compounds could be separated. The thermal release mercury peak temperatures of black mercury sulfide, red mercury sulfide, mercury oxide and mercury sulfate were about 290 C, 390 C, 505 C and 620 C respectively. The thermal release mercury peak of elemental mercury was exponential with the thermal release temperature. The form of mercury in the failure mercury adsorbent was black mercury sulfide, elemental mercury, red mercury sulfide, mercury oxide and mercury sulfate all were not shown. The starting temperature of thermal release mercury from the failure mercury adsorbent was about 160 C, and the ending temperature of thermal release mercury of black mercury sulfide and failure mercury adsorbent were both about 600 °C. Conclusions The failure mercury adsorbent would not decompose during unloading and transportation at room temperature, but it is necessary to avoid contracting with high temperature heat sources. The smelting temperature of cinnabar ore was generally 700-850 C, so the smelting temperature of cinnabar ore was also suitable for the removal of mercury in failure mercury adsorbent. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Inorganic Analytical Chemistry / Zhongguo Wuji Fenxi Huaxue is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We employ the Z-vector method in the four-component relativistic coupled-cluster framework to calculate the parity (P) and time-reversal (T) symmetry violating scalar-pseudoscalar nucleus-electron interaction constant (Ws), the effective electric field (Eeff) experienced by the unpaired electron, and the nuclear magnetic quadrupole moment-electron interaction constant (WM) in the open-shell ground electronic state of HgF. The molecular frame dipole moment and the magnetic hyperfine structure (HFS) constant of the molecule are also calculated at the same level of theory. The outcome of our study is that HgF has a high value of Eeff (115.9 GV/cm), Ws (266.4 kHz), and WM (3.59 × 1033 Hz/e cm2), which shows that it can be a possible candidate for the search of new physics beyond the standard model. Our results are in good agreement with the available literature values. Furthermore, we investigate the effect of the basis set and the virtual energy functions on the computed properties. The role of the high-energy virtual spinors is found to be significant in the calculation of the HFS constant and the P , T -odd interaction coefficients. [ABSTRACT FROM AUTHOR]

Mercury and its compounds are among the most dangerous and toxic substances in the environment. As part of the study, several exploratory analyses and statistical tests were conducted to demonstrate how low and stable mercury content is in municipal waste. A statistical analysis of the mercury content in waste (waste codes 19 12 12 and 20 03 01) was carried out using advanced IT tools. Based on 32 results for each waste, the maximum mercury concentration was 0.062 mg/kg dry weight (EWC code 19 12 12) and 0.052 mg/kg dry weight (EWC code 20 03 01). The analysis, data inference, and modeling were performed according to the CRISP-dm methodology. The results obtained were compared with the maximum allowable mercury concentrations for agricultural soils (2 mg/kg dry weight) and the provisions of the Minamata Convention (1 mg/kg). The average, median, and maximum observed mercury concentrations in waste are significantly lower than the assumed levels of 2 mg/kg (permissible concentrations for II-1 soils) and 1 mg/kg (Minamata Convention). The stability of mercury content in waste was examined. Descriptive statistics, statistical tests, and regression modeling were used. The tests and analyses performed showed an insignificant variation in the mercury content of the wastes with codes 19 12 12 and 20 03 01. No trend or seasonality was observed. The analyses and tests performed confirmed that the data are stable, and the values are low. [ABSTRACT FROM AUTHOR]

The problem of global environmental pollution by mercury is considered, including the sources, occurrence forms, and the specifics of mercury migration in surface water. Mercury and its compounds are among the priority biospheric pollutants. Global migration processes result in that various amounts of mercury can be seen in nearly all media of nonpolluted (background) natural ecosystems in various regions of Russia and in many world countries. The article presents data on mercury concentrations in river water in regions of Russia based on published data and the data of regular Roshydromet monitoring. The obtained results show a high heterogeneity of mercury compound concentrations in river water in various natural zones and altitudinal belts in Russia. Its concentrations vary from values below detection limit to those tens and hundreds of times the MAC, which corresponds to an extremely high level of water pollution. The highest concentrations were recorded in unique cases (the rivers of Ambarnaya, Norilka, Chumysh, Susuya, and Lyutoga). Despite of this, the median values of mercury concentration in river water in most cases are on the level below the detection limit of the method. [ABSTRACT FROM AUTHOR]

Zero discharge of desulfurization wastewater from coal-fired power plants has become important. Desulfurization wastewater and gypsum from different stages of the low-temperature triple-effect evaporation process of a coal-fired power plant were collected and investigated. The results showed that after low-temperature triple-effect evaporation, the concentrations of Na+, Mg2+, K+, and Cl− in the desulfurization wastewater increased by 7.91, 7.15, 8.49, and 8.35 times, respectively. With the progress of low-temperature triple effect evaporation process, the concentrations of As, Cd, Co, Cr, Cu, Mn, Se, and Zn in the wastewater after the triple effects were 5.85, 75.44, 1.28, 2.34, 13.66, 5.58, 8.59, and 4.35 times higher than those in the raw wastewater. Mn and Se exceeded the emission limits by 40 and 10 times, respectively. After triple-effect evaporation, the concentrations of As, Cd, Co, Cr, Cu, Pb, Se, and Zn in gypsum decreased to 46%, 26%, 66%, 41%, 35%, 97%, 39%, and 51% of the raw gypsum, respectively. Compared with that of other metal sulfates, the solubility of PbSO 4 was extremely low under low-temperature conditions, and some PbSO 4 precipitated during the triple-effect evaporation process, leading to a gradual decrease in the Pb concentration in the liquid phase. The mercury compounds in gypsum after the first and second effects were the same as those in raw gypsum, both of which were HgS and HgO. After third effect, the mercury compound in gypsum also included HgSO 4. In addition, owing to the promoting effect of the pH of desulfurization wastewater approaching 5.50 on the generation of HgS, the proportion of HgS gradually increased, and the proportion of HgO gradually decreased from the raw gypsum to the third effect gypsum. Therefore, the stability of the mercury compounds in gypsum was enhanced. It can provide a good reference for the migration and enrichment of heavy metals in the low-temperature triple-effect evaporation process, which is beneficial for the clean production and efficient utilization of coal. • Revealing the characteristics of low-temperature triple effect evaporation wastewater • Migration characteristics of heavy metals in low-temperature triple effect evaporation • Morphological transformation of mercury in wastewater • Realize concentrated and reduced discharge of desulfurization wastewater [ABSTRACT FROM AUTHOR]

Mercury (Hg) is a toxic contaminant of global concern and the impact on Arctic ecosystems, particularly in seabirds, is critical due to large-scale Hg transport towards polar regions and its biomagnification in marine trophic systems. While the adverse effects of Hg on reproductive processes in seabirds are established, the understanding of Hg maternal transfer pathways and their control on Hg reproductive toxicity is limited. The combination of Hg compounds speciation (inorganic mercury and monomethylmercury MMHg) and Hg stable isotope composition in the different egg compartments (yolk, albumen, membrane, and shell) before embryo development was investigated to provide information on (i) Hg maternal transfer mechanisms, (ii) influence of egg biochemical composition on Hg organotropism and (iii) proxies of inputs of Hg contamination. Eggs of three seabird species (the common eider, the black-legged kittiwake and the little auk) collected within the same breeding period (summer 2020) in East Greenland were investigated. For all seabirds, albumen and membrane, the most protein-rich compartments, were the most contaminated (from 1.2 to 2.7 μg g−1 for albumen and from 0.3 to 0.7 μg g−1 for membrane). In these two compartments, more than 82% of the total Hg amount was in the form of MMHg. Additionally, mass-dependent fractionation values (δ 202Hg) were higher in albumen and membrane in the three species. This result was mainly due the organotropism of MMHg as influenced by the biochemical properties and chemical binding affinity of these proteinous compartments. Among the different egg compartments, individuals and species, mass-independent fractionation values were comparable (mean ± sd were 0.99 ± 0.11‰, 0.78 ± 0.11‰, 0.03 ± 0.05‰, 0.04 ± 0.10‰ for Δ199Hg, Δ201Hg, Δ200Hg and Δ204Hg, respectively). We conclude that initial MMHg accumulated in the three species originated from Arctic environmental reservoirs exhibiting similar and low photodemethylation extent. This result suggests a unique major source of MMHg in those ecosystems, potentially influenced by sea ice cover. [Display omitted] • Protein-rich egg compartments exhibited highest Hg contamination, mostly as MMHg. • MDF values likely reflected Hg organotropism for protein-rich compartments. • Odd-isotopes MIF indicated a single origin of MMHg contamination among seabirds. • Egg membranes/shells are non-invasive indicators of the source of Hg contamination. [ABSTRACT FROM AUTHOR]

Mercury (Hg) is a naturally occurring heavy metal, but human activities and natural processes have led to increased pollution with Hg in the environment. Organic mercury, such as methyl mercury (MeHg), is considered more toxic than most inorganic mercury compounds. MeHg is rapidly taken up by aquatic organisms and bioaccumulates through the aquatic food web. The bioaccumulation causes high levels of MeHg in apex predators, such as pilot whales. Pilot whale meat is a traditional food source on the Faroe Islands; thus the consumption of pilot whale meat can lead to high Hg exposures in humans. The majority of the total Hg in pilot whale and fish is generally assumed to be MeHg. However, the relative amount of MeHg to total Hg can be highly variable. For risk assessment, it is relevant to know both the MeHg and the total Hg content. This study summarizes the knowledge of muscle MeHg concentrations relative to total Hg concentrations in pilot whales in the Faroe Islands. The pilot whale tissue was sampled during 1977–78, 1986–87, 2009–2010, and 2015. The 2015 samples included two pairs of fetuses/mothers. The results showed that the 1977–78 pilot whale muscle samples had lower relative concentrations of MeHg to total Hg compared to samples from the subsequent years. This discrepancy between early and later years could not solely be explained by increased demethylation related to concentration differences. Instead, the difference is more likely explained by variations in relative amounts of MeHg in prey of the pilot whales. In the fetuses the total Hg concentration was 20% of the Hg concentration in the mother. The relative MeHg concentrations in the fetuses were also lower (∼20%–30%) than in the mother. However, the MeHg to total Hg fraction in the fetus was similar or higher than in the mother. [Display omitted] • MeHg/TotHg ratios were analyzed in pilot whale muscle from Faroe Islands. • Higher relative ratios were observed in 1980's and 2009–2015 than in late 1970's. • Variation was likely related to different MeHg concentrations in prey. • MeHg concentrations were similar or higher in fetus compared to mother. [ABSTRACT FROM AUTHOR]

Mercury (Hg) mobilization and accumulation in the environment is directly related to forest fires. Biomass burning accounts for about 13% of the total contribution of Hg from natural sources. The aim of this work is to contribute to the knowledge of how wildfires modify mercury compounds behaviour and the effects it has in the Hg cycle, based on a systematic bibliographic review and analysis. Systems dynamics is an adequate focus to analyze the mobilization of Hg due to wildfires, which meets all the requirements to be studied by multimedia modelling. The development and application for the first time of a dynamic multimedia model of Hg taking into account specifically the influences of wildfires is one of the novelties of this work. Different scenarios show that an increase in the number of fires will consequently increase the mercury emitted into the atmosphere, modifying its natural cycle, producing a long-term modification of Hg compositions and concentrations in the different media. Hg movement caused by wildfires can cause complications in living beings and alter the ecosystems. This study found that the Hg soil content could as well be an indicator to measure the impact of fire on the environment. This model can also be generalized to conduct additional studies under comparable conditions, helping to understand the importance of forest fires in global Hg cycles. [ABSTRACT FROM AUTHOR]

Mercury and its compounds are highly concerned pollutants with strong neurotoxicity, but low concentration of mercury in the environment leads to problems of complex operation which are difficult to detect in traditional monitoring methods. Diffusive gradients in thin-films（DGT）is a fast-developing in-situ sampling technique that can effectively monitor mercury and other heavy metal pollutants. The principle, material development, application scenarios, and existing problems of Hg measured by the DGT device are discussed in detail in this paper. Combined with bibliometrics to find research hotspots and the use of different countries/ regions. Hg-DGT materials have been developed using single materials to nanocomposite materials, and the application conditions of different materials are listed emphatically. Environmental applications mainly include monitoring various chemical forms of Hg in water, monitoring the spatial distribution information of Hg in soil and sediments, evaluating bioavailability, and combining it with the DIFS model. There is mainly interference of dissolved organic matter, biofilm, Hg nanoparticles, and boundary diffusion layer. After a systematic review, three directions for the future development of Hg-DGT have been proposed. [ABSTRACT FROM AUTHOR]

The earthworm is the most beneficial organism for assessing metallic contamination due to the fact that critical high-quality correlations have been determined between earthworm steel concentrations and soil cadmium, copper, lead, zinc, and mercury concentrations. The mercury compounds are very poisonous for most organisms. Here, we investigated the ability of earthworms (Lumbricus terrestris) to HgCl2 (below laboratory conditions). A study of the effect of five different salt concentrations of mercury chloride (HgCl2) 1 ppm, 5 ppm, 10 ppm, 50 ppm, and 100 ppm was studied on worm survival and calculation of the concentration required to destroy half the number of worms (LC50). The results showed that there is an inverse relationship between these salt concentrations and the time required to perish 100% of worms. It was found that the concentration of 100 ppm is the lethal concentration of half the number (LC50) of the earthworm (Lumbricus terrestris). The effects of the salt concentrations used confirmed their effect on the experimental worm weights as well, so the concentration of 50 ppm was the most influential on earthworm weights of the type of Lumbricus terrestris, as it caused a reduction 12% of worm weights with a significant difference, while the concentrations 1 ppm and 100 ppm were the least effective, as they caused the worms to decrease by only (5%), while the remaining two concentrations 5 ppm and 10 ppm caused their effect to decrease by 7% only. Thus, it can be concluded that lower worm weights have nothing to do with the lethal concentrations of the heavy metal salt (HgCl2). The histological study also showed that low concentrations of mercury chloride salt have less effect on earthworms' skin tissue compared to higher concentrations. [ABSTRACT FROM AUTHOR]

Due to integrated pollution prevention and control measures and the reduced burning of coal, air concentrations of mercury (Hg 0 ) are currently levelling off. In the future, however, evasion from land surfaces will probably reverse this trend. Reasons are the rising temperatures and the loss of forest cover caused by calamities, droughts, storms and wildfires. Plant leaves constitute an important matrix for the accumulation of gaseous mercury and uptake and re-volatilisation by plants depends on the species, the vitality and the age and morphology of leaf organs. It has been shown that older conifer needles show higher concentrations than young needles and Hg accumulation is increasing throughout the season. In present study, we collected branches from Norway Spruce (Picea abies) in a former cinnabar mining region in Northern Palatinate, where artisanal and small-scale mining left innumerable waste dumps. While mining, smelting and processing of the ores were terminated during WWII, high total mercury concentrations remained in the top soils locally, with presumably only small fractions being plant available. In the lab, up to seven needle age classes were analysed. 1000 needle weights increased with age and as expected, also the Hg concentrations were elevated in the older needles. Needle concentrations were higher than those reported from other national biomonitoring programs confirming the regional imprint from legacy mercury. To complement our biomonitoring study, we collected edible mushrooms in former mining areas. Hg concentrations in most samples exceeded the EU maximum residue levels (MRL), while only a few broke the existing cadmium and lead limits. Tolerable weekly intake (TWI) for inorganic mercury would be surpassed with the consumption of a small portion of mushrooms. Further studies should be performed on the outgassing of Hg from mine wastes and the incorporation of Hg in the local food web, including its methylation and biomagnification., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Mercury is one of the metals used in mining, and when it is disposed of in the soil or water, its distribution and toxic exposure are magnified. The use of microorganisms to remove metals in water provides some opportunities to explore their impact. The objective of this research is to explore the ability to tolerate mercury, of isolates of Pseudomonas spp. gender, recovered from sewage. Water from the Ciénega de Ayapel (Córdoba) and the Cauca River, in Caucasia (Antioquia), were taken and analyzed microbiologically: spread on the Cetrimide agar and biochemical identification by Vitek (bioMérieux). The Pseudomonas spp. isolates were exposed to mercuric sulfate concentrations supplementing BHI medium, using the tube technique (up to 500 mg/L) and microplate (up to 75 mg/L), to identify the tolerance to the metal. As a result, we obtained six Pseudomonas spp. isolates with the capacity to grow in concentrations between 75 and 400 mg/L of mercuric sulfate, showing viability, precipitation, pigmentation, and fluorescence in the medium as protection mechanisms against the metal. Pseudomonas species have been mentioned in several experiments related to the removal of mercury and derived compounds. In conclusion, it was determined that native isolates of Pseudomonas with the ability to tolerate different concentrations of mercury could be used in processes that accompany the removal of this metal, going deeper into the interaction mechanism with the metal so that it is applied in future leachates obtained from mining before being disposed of in the river. [ABSTRACT FROM AUTHOR]

Hyperammonemia is a metabolic condition characterized by elevated levels of ammonia and a common event in acute liver injury/failure and chronic liver disease. Even though hepatic ammonia levels are potential predictive factors of patient outcome, easy and inexpensive methods aiming at the detection of liver ammonia accumulation in the clinical setting remain unavailable. Thus, herein we have developed a morphological method, based on the utilization of Nessler´s reagent, to accurately and precisely detect the accumulation of ammonia in biological tissue. We have validated our method against a commercially available kit in mouse tissue samples and, by using this modified method, we have confirmed the hepatic accumulation of ammonia in clinical and animal models of acute and chronic advanced liver injury as well as in the progression of fatty liver disease. Overall, we propose a morphological method for ammonia detection in liver that correlates well with the degree of liver disease severity and therefore can be potentially used to predict patient outcome.

Children's exposure to mercurial skin lightening agents at any time during their development, from intra-uterine to early developmental life, can lead to severe detrimental health effects. This is because these skin lightening agents contain inorganic mercury as their active ingredient at varying concentrations that exceed acceptable levels. Mercury does not confer any physiological benefit to the human body, and as such, it has only been linked to numerous adverse effects on users and may pose a possible health risk for children born to, living with, and in contact with skin bleaching agent users. Although studies have shown that inorganic mercury exposure may be detrimental to children, there is a paucity of data, to the best of our knowledge, on reviews exploring specifically the possible routes of exposure to and effects of mercurial skin lightening agents on children. Since prevention is the only key to reducing mercury poisoning and toxicity, this study aims to extensively review the literature on prenatal and postnatal exposure to mercury in children from cosmetic skin lightening agents and discuss possible detrimental effects.

Copyright of Nachrichten aus der Chemie is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Using ethnographic data, this article suggests that the therapeutic use of various mercury compounds in siddha medicine has so far not decreased despite international regulation of the substance and discussions surrounding the safety of mercury. Siddha practitioners portray mercury as central to their therapeutics. The article demonstrates this for different contexts, including the preparation of mercuric medicines; the production of mercury amulets; and recent research studies on mercury-based siddha drugs, targeting, for instance, dementia-related syndromes. Contextualizing siddha mercurial procedures and preparations through interlinking therapeutic, historical, and global frames underscores the fact that mercury use in siddha medicine today derives from alchemical traditions, but also transcends them. It is embedded in political contexts of science and healthcare in India, as it answers to concerns about safety and toxicity and at the same time takes center stage in negotiating siddha medical specialty and alterity vis-à-vis other medical practices, most notably ayurveda. [ABSTRACT FROM AUTHOR]

Prior research into the association between prenatal mercury (Hg) exposure and the secondary sex ratio has yielded inconclusive and conflicting results. Notably, no study has used cord blood Hg measurement in this context. Also, the differences in Hg species and the potential modifying role of selenium (Se) on this association remain unexplored. Using data from the Japan Environment and Children's Study, we analyzed mother-child pairs with available data for concentrations of total mercury (THg) and Se in maternal blood during late pregnancy, and THg, inorganic mercury (IHg), methylmercury (MeHg), and Se in cord blood. Logistic regression models were employed to examine the association between Hg and Se biomarkers and the secondary sex ratio. Out of the total sample of 3698 children, 1877 (50.8 %) were male, corresponding to an overall secondary sex ratio of 1.03. After adjusting for maternal age and parity, no significant associations were observed between THg concentrations of maternal blood and the secondary sex ratio. Nevertheless, we identified that two-fold increases in THg, IHg, and MeHg concentrations in cord blood were positively associated with increased odds of having a male child, yielding adjusted odds ratios of 1.13 (95 %CI: 1.04, 1.22), 1.12 (1.03, 1.21), and 1.12 (1.03, 1.22), respectively. When stratified by the median Se concentrations, no apparent differences were detected in the associations between Hg concentrations and the secondary sex ratio. In summary, elevated Hg concentrations in cord blood, but not maternal blood, were associated with an increased probability of male births., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Mercury (Hg) stable isotope ratios supplemented by Hg solid speciation data were determined in soils in a former Fe-Hg mining/smelting area (Jedová hora, Czech Republic, Central Europe). The dominant Hg phase in the studied soils was found to be cinnabar (HgS). A secondary form of soil Hg(II) was represented by Hg weakly and strongly bound to mineral (micro)particles, as revealed by thermo-desorption analysis. These Hg species probably play a key role in local soil Hg processes and biogeochemical cycling. The Hg isotopic data generally showed small differences between HgS (-1.1 to -0.8‰; δ 202 Hg) and the soil samples (-1.4 to -0.9‰; δ 202 Hg), as well as limited isotopic variability within the two studied soil profiles. On the other hand, the detected negative δ 202 Hg shift (∼0.4‰) in organic horizons compared to mineral soils in the highly contaminated profile suggests the presence of secondary post-depositional Hg processes, such as sorption or redox changes. For the less contaminated profile, the observed Hg isotopic variation (∼0.3‰; δ 202 Hg) in the subsurface mineral soil compared to both overlying and underlying horizons is likely due to cyclic redox reactions associated with Hg isotopic fractionation. We assume that the adsorption of Hg(II) to secondary Fe(III)/Mn(III,IV)-oxides could be of major importance in such cases., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

HgTe plates have been grown by vapor phase epitaxy on (111) SrTiO3 substrates with a preferred orientation in the (111) crystalline direction, as indicated by x-ray diffraction. Examination of the plates using the micro-Raman mapping shows that the HgTe plates exhibit unusual strain patterns: the Raman peaks from the transverse-optical and longitudinal-optical phonons for the thicker (central) parts of the HgTe plates are at the same frequency as that of the bulk HgTe, while the Raman peaks for the thinner parts of the HgTe plates, which surround the thicker parts and can hardly be seen in a scanning electron microscope, are significantly larger in frequency. The full width at half maximum is smaller in the thinner areas than in the thicker parts. Theoretical analysis shows that the HgTe plates on SrTiO3 substrates suffer from compressive stress, and this may be sufficient to induce the three-dimensional topological insulator behavior in HgTe. [ABSTRACT FROM AUTHOR]

The solvothermal reaction of 4,4′-bipyridine (Bipy) and mercury nitrate in a mixed acetonitrile/water solution leads to a novel mercury coordination compound with the in situ formation of cyanide ions Hg(Bipy)(CN)2 (1). Its structure is determined by single crystal X-ray diffraction (XRD), and further characterized by powder XRD, elemental analysis, and IR spectroscopy. Compound 1 exhibits a 1D zigzag [Hg(Bipy)(CN)2]n chain structure. The solid-state photoluminescent properties of 1 are also investigated. [ABSTRACT FROM AUTHOR]

In this paper, investigations were carried out on the effects of simultaneous partial substitution of Tl at the Hg site on the physical properties of an Hg1- xTlxBa2Ca2Cu3O8+δ cuprate superconductor with x= 0, 0.1, 0.2, 0.3 and 0.4. Two steps of the solid state reaction method were used to prepare samples in capsule. The results showed that the optimum sintering temperature was equal to 850 ᵒC and the sintering time was equal to 20 h for the prepared samples. The best conditions for constitution and stabilization of the high Tc phase-1223 were obtained by investigating the effects of Tl substitution on Hg site and oxygen content (δ) on the superconducting properties. Structural investigation revealed that all the samples have a tetragonal structure with two phases, namely an Hg-1223 high Tc phase as a main phase and an Hg-1212 low Tc phase. Besides, some impurity phases like CuO and CaHgO2 were found. The increase of Tl content in Hg1-xTlxBa2Ca2Cu3O8+δ compound from 0 to 0.4 caused a change in the lattice parameter, density of the unit cell (ρm), and c/a values. HgBa2Ca2Cu3O8+δ compound exhibited a critical transition temperature that is equal to 115 K. On the other side, the results showed that the highest Tc was 119 K for Hg0.8Tl0.2 Ba2Ca2Cu3O8+δ. The oxygen content (δ= 0.46) was expected to be the optimum hole doping for Hg0.8Tl0.2 Ba2Ca2Cu3O8+δ compound, which means in our opinion that δ plays a remarkable role in the assessment of Tc. [ABSTRACT FROM AUTHOR]

Mercury Fulminate (MF) is one of the well-known primary explosives since 17th century and it has rendered invaluable service over many years. However, the correct molecular and crystal structures are determined recently after 300 years of its discovery. In the present study, we report pressure dependent structural, elastic, electronic and optical properties of MF. Non-local correction methods have been employed to capture the weak van derWaals interactions in layered and molecular energetic MF. Among the non-local correction methods tested, optB88-vdW method works well for the investigated compound. The obtained equilibrium bulk modulus reveals that MF is softer than the well known primary explosives Silver Fulminate (SF), silver azide and lead azide. MF exhibits anisotropic compressibility (b > a > c) under pressure, consequently the corresponding elastic moduli decrease in the following order: C22 > C11 > C33. The structural and mechanical properties suggest that MF is more sensitive to detonate along c-axis (similar to RDX) due to high compressibility of Hg···O non-bonded interactions along that axis. Electronic structure and optical properties were calculated including spin-orbit (SO) interactions using full potential linearized augmented plane wave method within recently developed Tran-Blaha modified Becke-Johnson (TB-mBJ) potential. The calculated TB-mBJ electronic structures of SF and MF show that these compounds are indirect bandgap insulators. Also, SO coupling is found to be more pronounced for 4d and 5d-states of Ag and Hg atoms of SF and MF, respectively. Partial density of states and electron charge density maps were used to describe the nature of chemical bonding. Ag--C bond is more directional than Hg--C bond which makes SF to be more unstable than MF. The effect of SO coupling on optical properties has also been studied and found to be significant for both (SF and MF) of the compounds. [ABSTRACT FROM AUTHOR]

Ultraviolet light induced photofragmentation of mercury compounds is studied experimentally with electron energy resolved photoelectron-photoion coincidence techniques and theoretically with computational quantum chemical methods. A high resolution photoelectron spectrum using synchrotron radiation is presented. Fragmentation of the molecule is studied subsequent to ionization to the atomic-mercury-like d orbitals. State dependent fragmentation behaviour is presented and specific reactions for dissociation pathways are given. The fragmentation is found to differ distinctly in similar orbitals of different mercury compounds. [ABSTRACT FROM AUTHOR]

The industrial design and development of microwave-induced volatilization of hazardous substances in waste greatly depend on their dielectric properties. The dielectric properties of different mercury compounds in spent mercury-containing catalyst (SAC) were investigated by the cavity perturbation method at different temperatures. The decomposition absorption mechanisms for HgS and HgCl2 show the same trend according to thermogravimetric analysis results over the temperature range of interest. The SAC composite exhibits sufficient microwave absorption from 20 °C to approximately 600 °C owing to the superior dielectric properties of non-volatile mercury-containing compounds (HgCl2 and HgS). At temperatures above 600 °C, the dielectric properties of the SAC are determined by the residual mercury and carbon matrix. Phase analyses indicate that the entire process of microwave heating could be divided into three stages: (1) The volatilization temperature of unbound water and some impurities are between 20 °C and 100 °C; (2) The main thermal disintegration region of mercury species is between 100 °C and 600 °C; (3) HgCl2 and HgS volatilize completely to gas at 600 °C. Meanwhile, HgCl2 decomposing more readily than HgS.

There are few studies on mercury content in hypersaline waters. Mercury content was studied in Bay Sivash (the Sea of Azov), the world's largest hypersaline lagoon with a strong salinity gradient from 36 to 90 g l−1. The dissolved mercury compounds ranged from 120 to 250 ng l−1, Hg varied from 60 to 450 ng l−1 in the suspended matter, and total mercury in the water ranged from 200 to 600 ng l−1. Salinity and the total suspended matter had practically no effect on the amount of dissolved and suspended forms of mercury separately, but their growth significantly increased total mercury content in water. Only the concentration of dissolved forms of mercury in water significantly correlated with dissolved organic matter. The Hg concentration in the bottom sediments averaged 13.8 ng g−1 wet weight. Both high salinity and human activities on the Sivash drainage area are responsible for high Hg content in lagoon water. [ABSTRACT FROM AUTHOR]

To establish a standardized method for specifying mercury in solid samples, a database of relevant mercury species is created via thermo‐desorption. By measuring Hg(t) and Hg(0), different evaporation characteristics of mercury halides, sulfide, oxides, nitrates, and sulfates were recorded. It was possible to create a baseline for analyzing solid samples with unknown mercury content. All mercury species without a halide compound evaporate over 200 °C and as elemental mercury. All mercury halides evaporate mainly as oxidized species. From this fact it can be concluded that mercury halides desublimate when heated and have a vapor pressure as a solid. This unique characteristic was only seen by mercury halides. All other species seem to decompose into their single components when heated. [ABSTRACT FROM AUTHOR]

Ultrafast acoustics measurements on liquid mercury have been performed at high pressure and temperature in a diamond anvil cell using picosecond acoustic interferometry. We extract the density of mercury from adiabatic sound velocities using a numerical iterative procedure. We also report the pressure and temperature dependence of the thermal expansion, isothermal and adiabatic compressibility, bulk modulus, and pressure derivative of the latter up to 7 GPa and 520 K. We finally show that the sound velocity follows a scaling law as a function of density in the overall measured metallic state. [ABSTRACT FROM AUTHOR]

The effect of the spin-orbit interaction to photofragmentation is investigated in the mercury(II) bromide (HgBr2) molecule. Changes in the fragmentation between the two spin-orbit components of Hg 5d photoionization, as well as within the molecular-field-splitted levels of these components are observed. Dissociation subsequent to photoionization is studied with synchrotron radiation and photoelectron-photoion coincidence spectroscopy. The experimental results are accompanied by relativistic ab initio analysis of the photoelectron spectrum. [ABSTRACT FROM AUTHOR]

The health effects of mercury vapor exposure on the brain in volcanic areas have not been previously addressed in the literature. However, 10% of the worldwide population inhabits in the vicinity of an active volcano, which are natural sources of elemental mercury emission. To evaluate the presence of mercury compounds in the brain after chronic exposure to volcanogenic mercury vapor, a histochemical study, using autometallographic silver, was carried out to compare the brain of mice chronically exposed to an active volcanic environment (Furnas village, Azores, Portugal) with those not exposed (Rabo de Peixe village, Azores, Portugal). Results demonstrated several mercury deposits in blood vessels, white matter and some cells of the hippocampus in the brain of chronically exposed mice. Our results highlight that chronic exposure to an active volcanic environment results in brain mercury accumulation, raising an alert regarding potential human health risks. These findings support the hypothesis that mercury exposure can be a risk factor in causing neurodegenerative diseases in the inhabitants of volcanically active areas. [ABSTRACT FROM AUTHOR]

Background: Thimerosal (TM) is a toxic, organometallic mercury compound (which releases ethyl-mercury-containing compounds in aqueous solutions) used as a preservative in vaccines. Mitochondria are organelle which are highly vulnerable to many chemical compounds, including mercury (Hg) and its derivatives., Method: Wistar rats (at 21 days of age) were used to model a child's TM exposure following childhood vaccination, divided in two groups: TM exposed (20 μg/kg/day) and unexposed controls (saline solution), both for 24 h. Atomic Fluorescence Spectrometry was used to quantify the amounts of mercury in tissues. The electron transport chain (ETC) from isolated mitochondria was evaluated using an oxygen electrode. The mitochondrial membrane potential and H 2 O 2 production were analyzed using selective fluorescence probes. The activity of some enzymes (SOD, CAT, GPx, and AChE) and secondary markers of oxidative stress (GSH, GSSG, total free thiol) were also examined in tissues., Results: Hg accumulation in the brain and liver was higher in exposed animals when compared to the control. Liver-isolated mitochondria showed that TM improved respiratory control by 23%; however, states 3 and 4 of the ETC presented a decrease of 16% and 37%, respectively. Furthermore, brain-isolated mitochondria presented an improvement of 61% in respiratory control. Brain enzyme activities were significantly impacted in TM-exposed rats compared to unexposed rats as follows: decreases in SOD (32%) and AChE (42%) and increases in GPx (79%) and CAT (100%). GPx enzyme activity in the liver was significantly increased (37%). Among secondary oxidative stress markers, the brain's total reduced thiol (SH) concentration was significantly increased (41%)., Conclusion: Acute TM treatment exposure in a Wistar rat model mimicking TM exposure in an infant following childhood vaccination significantly damaged brain bioenergetic pathways. This study supports the ability of TM exposure to preferentially damage the nervous system., Competing Interests: Declaration of Competing Interest All the authors have no financial and personal relationships with other people or organizations that could inappropriately influence this work. The data that support the findings of this study are available from the corresponding author upon reasonable request., (Copyright © 2024 Elsevier GmbH. All rights reserved.)