Mercury Sulfide Research Articles

Adaptive mechanisms induced by sparingly soluble mercury sulfide (HgS) in zebrafish: Behavioural and proteomics analysis

Mercury (Hg) causes great health concerns due to its extreme neurotoxicity. However, here we show that pretreatment of sparingly soluble mercury compound (HgS) could induce adaptive mechanisms in zebrafish, which can resist the neurotoxic effects of mercury chloride (HgCl2). In this study, zebrafish were treated with HgS (in the form of 99% HgS arising from traditional Ayurvedic medicine Rasasindura (RS), chosen for its particle and crystallite sizes). This work was prompted by the traditional use of this form of HgS to treat nervous and immune-related diseases. Our investigation on zebrafish behaviour showed that RS pretreated fish group (RS-HG) was less severely affected by HgCl2 exposure, as compared to the RS non-treated (VC-HG) group. Further, biochemical tests showed that RS pretreatment prevents alteration of reactive oxygen species (ROS), acetylcholinesterase (AChE), and cortisol as compared to the VC-HG group. Proteomics and bioinformatics studies of zebrafish brain tissues suggested that Rasasindura (RS-HG group) protects alteration of various protein expression related to KEGG pathways, including citrate cycle (TCA cycle) and glutathione metabolism that are directly or indirectly linked to the oxidative stress, against HgCl2 induced neurotoxicity. We found that adaptive mechanisms were initiated by the initiation of response to stress (enrichment of GO:0006950 pathway), due to the accumulation of a small amount of ionic Hg (60 ± 10 ng/g) after 15 days of RS treatment. These adaptive mechanisms avoid further adverse neurotoxicity of HgCl2. Thus, HgS (RS) pretreatment can induce protective effects in zebrafish.

Preparation and crystallographic studies of a new mercuric salicylaldimine complex for fabrication of microscaled and nanoscaled mercuric sulfide as antimicrobial agents against human pathogenic yeasts and filamentous fungi

The new mercuric complex [Hg(HL)2Cl2] incorporating salicylaldimine ligand (HL = 2‐((pyridin‐3‐ylimino)methyl)phenol) was fabricated where the ligand molecules behaved in a monodentate manner via their pyridine nitrogen atoms. In addition to elemental characterization, X‐ray crystallographic studies of the complex revealed its packing in a monoclinic crystal system (space group:I2/a,a= 13.4276(2) Å,b= 6.20950(10) Å,c= 27.7530 (4) Å,α=γ= 90°, andβ= 98.1610(10)°). Hydrothermal treatment of [Hg(HL)2Cl2] with thioacetamide afforded HgS microparticles (HgS μPs; Brunauer–Emmett–Teller [BET] surface area = 6.205 m2/g, diameter = 196.53–259.13 nm, and average size = 213.27 nm), whereas these microparticles were transformed to nanoscaled HgS particles (HgS NPs; BET surface area = 14.380 m2/g, diameter = 58.87–90.56 nm, and average size = 72.78 nm) by the action of ultrasonication. The as‐prepared HgS, HgS NPs in particular, afforded remarkable microbicidal activity against eight strains of filamentous and unicellular human pathogenic fungi and yeasts in comparison with cycloheximide. Remarkably,Aspergillus terreusgrew up to 34.7 ± 1.88 mm in the absence of any fungicide, but HgS μPs, HgS NPs, and cycloheximide limited the fungal growth to 26 ± 0.94, 12.33 ± 1.6, and 28.3 ± 1.7 mm after incubation for 6 days. Besides, inhibition ofRhodotorula glutiniswas of 7.6 ± 0.01 × 107CFU/ml in control sample, but experiments included HgS μPs, HgS NPs, and cycloheximide limited the colony‐forming units ofR. glutinisto 4.2 ± 0.01 × 107, 3.5 ± 0.02 × 107, and 5.9 ± 0.05 × 107CFU/ml.

Cinnabar-containing Chinese medicine Hua-Feng-Dan differs from mercury sulfide and mercury chloride in affecting gut microbiota in mice

Cinnabar-containing Chinese medicine Hua-Feng-Dan differs from mercury sulfide and mercury chloride in affecting gut microbiota in mice

Cinnabar-containing Chinese medicine Hua-Feng-Dan differs from mercury sulfide and mercury chloride in affecting gut microbiota in mice

Cinnabar-containing Chinese medicine Hua-Feng-Dan differs from mercury sulfide and mercury chloride in affecting gut microbiota in mice

Development of a technology for immobilizing mercury in solid mercury-containing wastes

According to United Nations Environment Programme technical guidelines there are two main chemical approaches to the immobilization mercury in chemical conversion to mercury sulfide and amalgamation. This article is devoted to the development of a general approach to the wastewater-less method of mercury conversion to mercury sulfide in solid waste carried out under normal conditions. The solid-phase reaction of mercury from sulfur carried out in ball or vibration mills, is proposed to use. The article presents an original technological scheme. It was found that, for energy efficiency, the duration of the interaction of mercury-containing waste with sulfur for 1.5–2 ​h is appropriate. The remaining mercury to safe concentrations in the approach developed by the authors is to be immobilized by the addition of oxidizing agents. An original method is devoted to removing reaction masses from apparatuses, which using a homogenizing medium based on bentonite. In the paper determined the optimal concentration of GNB-30 brand bentonite in the suspension (2.5% of the weight). The optimal amount of homogenizing medium is 80% or more. Additionally, It was found that from 30 to 60% of mercury oxide can be converted to mercury sulfide with an excess of sulfur (mercury: sulfur ​= ​1: 3) and a grinding time of 1.5–2 ​h. • Development of a technological scheme for the stabilization of mercury in waste. • Dependence of the Hg 0 immobilization % at reaction with S 8 on various parameters. • Selection of the amount of bentonite and water as a homogenizing medium. • Immobilization results of HgO in reaction with S 8 .

Unveiling Hg-binding protein within black deposit formed on Golgi-Cox-stained brain neuron

BackgroundGolgi-Cox staining has been conventionally used for investigating neuronal development. After the brain tissue is subject to Golgi-Cox staining, black deposits are formed on the surface of the stained neurons because of mercuric sulfide, which does not show a fluorescence response under two-photon excitation. However, we unexpectedly observed fluorescence emitted by these black deposits during two-photon fluorescence measurements. Further, the in-depth of physical and chemical methods analysis revealed that the black deposits on the stained neurons are composed of Hg-binding proteins. MethodsWe studied black deposits present in the Golgi-Cox-stained mouse brain neurons using techniques such as multiple-photon microscopy, scan electron microscopy, micro-Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. ResultsThe emitted fluorescence was because of the fluorescence groups of Hg-binding protein present within the Golgi-Cox deposits on the neuronal surface. ConclusionsThe presence of Hg-binding proteins within black deposits on the surface of Golgi-Cox-stained neurons was proven for the first time. The novel interaction between the neurons and Hg2+ ions during Golgi-Cox staining help to understand the mechanism of Golgi-Cox staining.

Mercury Removal from Wastewater Using Cysteamine Functionalized Membranes.

This study demonstrates a three-step process consisting of primary pre-filtration followed by ultrafiltration (UF) and adsorption with thiol-functionalized microfiltration membranes (thiol membranes) to effectively remove mercury sulfide nanoparticles (HgS NPs) and dissolved mercury (Hg2+) from wastewater. Thiol membranes were synthesized by incorporating either cysteine (Cys) or cysteamine (CysM) precursors onto polyacrylic acid (PAA)-functionalized polyvinylidene fluoride membranes. Carbodiimide chemistry was used to cross-link thiol (−SH) groups on membranes for metal adsorption. The thiol membranes and intermediates of the synthesis were tested for permeability and long-term mercury removal using synthetic waters and industrial wastewater spiked with HgS NPs and a Hg2+ salt. Results show that treatment of the spiked wastewater with a UF membrane removed HgS NPs to below the method detection level (<2 ppb) for up to 12.5 h of operation. Flux reductions that occurred during the experiment were reversible by washing with water, suggesting negligible permanent fouling. Dissolved Hg2+ species were removed to non-detection levels by passing the UF-treated wastewater through a CysM thiol membrane. The adsorption efficiency in this long-term study (>20 h) was approximately 97%. Addition of Ca2+ cations reduced the adsorption efficiencies to 82% for the CysM membrane and to 40% for the Cys membrane. The inferior performance of Cys membranes may be explained by the presence of a carboxyl (−COOH) functional group in Cys, which may interfere in the adsorption process in the presence of multiple cations because of multication absorption. CysM membranes may therefore be more effective for treatment of wastewater than Cys membranes. Focused ion beam characterization of a CysM membrane cross section demonstrates that the adsorption of heavy metals is not limited to the membrane surface but takes place across the entire pore length. Experimental results for adsorptions of selected heavy metals on thiol membranes over a wide range of operating conditions could be predicted with modeling. These results show promising potential industrial applications of thiol-functionalized membranes.

Enhanced Enantioselectivity in the Synthesis of Mercury Sulfide Nanoparticles through Ostwald Ripening

Chirality in nanoparticles (NPs) has recently emerged as an active area of research owing to its wide range of potential applications. NPs with intrinsic chirality in their inorganic core are of pa...

Onshore mud volcanoes as a geological source of mercury: Case study from the Kerch Peninsula, Caucasus continental collision zone

Three mud volcanoes (MVs) in the Kerch Peninsula were studied as a geological source of mercury. The study focused on total mercury (THg) concentrations in MV waters, mud masses and plants colonizing MV areas; gaseous elemental mercury (GEM) in the atmosphere above MVs; and sulfide mercury (HgS) and HgCl2 species in representative samples of mud masses. THg concentrations in the illite-smectite mud masses ranged from 38 to 920 ng/g. They contained up to 70% of total mercury in sulfide form (in pyrite and cinnabar), but lacked HgCl2. THg values in MV waters of HCO3-Cl/Na- and/or Cl-HCO3/Na-types with рН = 7.4–9.5 mostly fell in a range of 79–440 ng/L, but rarely exceeded 600 ng/L, being comparable with those for geothermal systems. Another issue of interest was the distribution of THg in below- and above-ground parts of halophyte plant Limonium caspium. THg was incorporated into the plant roots, leaves and flowers; the roots exhibited higher concentrations of THg relative to the other organs. The Hg bioaccumulation factor ranged from 0.06 to 0.76. GEM concentrations measured over large bubbling MV pools and newly formed cracks showed values (50 to 520 ng·m−3) higher than background values (≤3 ng·m−3) associated with pristine test sites and background values measured within three MV areas of the Kerch peninsula that is slightly higher than background concentration for the Northern Hemisphere. Maximum GEM contents were comparable with the values found in geothermal and magmatic volcanic provinces.

Mercury source in Copan (Honduras): Local mining or trade?

Mercury was widely used in the art and rituals of the pre-Columbian Maya. A large amount (>6 kg) of documented liquid mercury has been recovered in Maya cultural deposits at Copan, Honduras. The Copan Acropolis also contains abundant evidence of cinnabar (mercury sulfide) use in ritual practice: sprinkled over tomb surfaces; coating the bones of the dead; and covering offerings. Discovering the specific source of cinnabar and liquid mercury used in Copan will contribute to further interpretations of economic networks utilized by the Copan Maya. The geology of the Copan Valley supports the hypothesis that mercury could be mined locally. To test it we designed a geochemical survey on the stream network within the Copan watershed basin using portable X-ray Fluorescence Spectrometry (pXRF) analysis. Results of the survey confirmed data from previous geologic mapping, indicating the presence of mercury in the valley. However, its concentrations are extremely low, sporadic and do not support its potential as a mining source. Therefore, it is very likely that mercury found in Copan ritual contexts was brought from elsewhere either as tribute or through trading.

Measuring and mitigating mercury vapour in the collection cabinets at Museums Victoria

Mercury is present in the Museums Victoria collections in a variety of forms. These include mercuric chloride applied as a pesticide, pigments and paints containing mercury sulfide, scientific equipment containing liquid mercury and geoscience specimens including native mercury and cinnabar. All these materials can release mercury vapour into storage cabinets and have the potential to contaminate both storage surfaces and other nearby specimens. Extensive testing identified higher than acceptable levels of mercury vapour inside storage cabinets. Air from cabinets was sampled across all collecting disciplines including First Peoples, Society and Technology and Natural Sciences. Results showed levels of mercury vapour above 25 μg/m3 (TWA) in cabinets of bird skins and First Peoples’ artefacts treated with mercuric chloride pesticides and above 150 μg/m3 (TEEL) in the mineralogy collection. Mercury contamination was also detected on cabinet surfaces and storage boxes. Mitigation strategies implemented to reduce or handle this hazard include enclosing mercury minerals in gas barrier film, replacing contaminated cabinets with vented cabinets and engineering controls during the handling of specimens. Improved staff practices include procedures to dissipate vapour before accessing cabinets. Follow up testing confirmed a significant reduction of mercury vapour levels after the implementation of these mitigation strategies.

Effects of Extracellular Polymeric Substances on the Formation and Methylation of Mercury Sulfide Nanoparticles.

Growing evidence has suggested that microbial biofilms are potential environmental "hotspots" for the production and accumulation of a bioaccumulative neurotoxin, methylmercury. Here, we demonstrate that extracellular polymeric substances (EPS), the main components of biofilm matrices, significantly interfere with mercury sulfide precipitation and lead to the formation of nanoparticulate metacinnabar available for microbial methylation, a natural process predominantly responsible for the environmental occurrence of methylmercury. EPS derived from mercury methylating bacteria, particularly Desulfovibrio desulfuricans ND132, substantially increase the methylation potential of nanoparticulate mercury. This is likely due to the abundant aromatic biomolecules in EPS that strongly interact with mercury sulfide via inner-sphere complexation and consequently enhance the short-range structural disorder while mitigating the aggregation of nanoparticulate mercury. The EPS-elevated bioavailability of nanoparticulate mercury to D. desulfuricans ND132 is not induced by dissolution of these nanoparticles in aqueous phase, and may be dictated by cell-nanoparticle interfacial reactions. Our discovery is the first step of mechanistically understanding methylmercury production in biofilms. These new mechanistic insights will help incorporate microbial EPS and particulate-phase mercury into mercury methylation models, and may facilitate the assessment of biogeochemical cycling of other nutrient or toxic elements driven by EPS-producing microorganisms that are prevalent in nature.

Selenide functionalized natural mineral sulfides as efficient sorbents for elemental mercury capture from coal combustion flue gas

Directly using earth-abundant natural mineral sulfides (MSs) for elemental mercury (Hg0) removal from coal combustion flue gas remains a challenge because extremely low surface areas of natural MSs largely suppressed their capabilities in Hg0 immobilization. In this work, a new mindset was proposed for the activation of natural MSs by introducing surface selenide (Se2−) ligands to achieve an efficient and rapid Hg0 uptake from coal combustion flue gas. The Se2− loaded pyrrhotite (xSe-FeS) exhibited four folds higher Hg0 uptake rate compared to bare pyrrhotite. The immobilized mercury over the xSe-FeS surface was primarily converted into mercury sulfide (HgS), a mercury species known for its extreme stability when environmentally exposed. The superiority of xSe-FeS was ascribed to that Hg0 bound more weakly with active selenide sites than sulfide sites, and the lower binding energy decreased the diffusion barrier of mercury and improve the reaction rate. The same mindset was proven to be also applicable in tailoring other natural MSs into efficient Hg0 sorbents. From these advantageous perspectives, this work provides a highly promising way for efficiently utilizing naturally enriched MSs as economically feasible and scientifically sound sorbents for Hg0 removal from coal combustion flue gas.

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การผลิตตัวดูดซับไอออนปรอทและไอออนซัลไฟด์จากยางรถยนต์ใช้แล้ว

Mercury(II) N,N′-diarylformamidine dithiocarbamates as single-source precursors for the preparation of oleylamine-capped HgS nanoparticles

Mercury(II) complexes of N,N′-diarylformamidine dithiocarbamate of the general formula [Hg-(L)2] (L = N,N′-bis(2,6-dimethylphenyl)formamidine dithiocarbamate L1 (1), N,N′-bis(2,6-disopropylphenyl) formamidine dithiocarbamate L2 (2), N,N′-mesityl formamidine dithiocarbamate L3 (3), N′-(2,6-dichlorophenyl-N-(2,6-dimethylphenyl) formamidine dithiocarbamate L4 (4), N′-(2,6-dichlorophenyl)-N-(2,6-diisopropylphenyl) formamidine dithiocarbamate L5 (5) and N′-(2,6-dichlorophenyl)-N-mesityl formamidine dithiocarbamate L6 (6)) have been synthesized and characterized by physicochemical and spectroscopic techniques. The molecular structures of 1, 2 and 6 were unequivocally determined using single-crystal X-ray diffraction as mononuclear species in which the Hg(II) centers are coordinated to four sulfur atoms from two dithiocarbamate ligands resulting in distorted square planar geometries. Complexes 1, 3 and 6 were used as single-source precursors to prepare mercury sulfide nanoparticles HgS1, HgS3 and HgS6 in oleylamine which acted as the solvent as well as the capping agent. HR-TEM images of HgS1, HgS3 and HgS6 particles are nanospherical in shape with size distribution between 5 and 16 nm. Powder XRD pattern confirmed the β phase (metacinnabar) of HgS in all the nanoparticles with an average crystallite size similar for HgS1 and HgS3, 9.35 and 9.46 nm, respectively, and smaller crystallite sizes, 5.15 nm for HgS6. The optical properties information obtained from the UV–visible and photoluminescence spectra of the HgS nanoparticles showed evidence of quantum confinement.

Microbial colonization of metal sulfide minerals at a diffuse-flow deep-sea hydrothermal vent at 9°50'N on the East Pacific Rise.

Metal sulfide minerals, including mercury sulfides (HgS), are widespread in hydrothermal vent systems where sulfur-oxidizing microbes are prevalent. Questions remain as to the impact of mineral composition and structure on sulfur-oxidizing microbial populations at deep-sea hydrothermal vents, including the possible role of microbial activity in remobilizing elemental Hg from HgS. In the present study, metal sulfides varying in metal composition, structure, and surface area were incubated for 13days on and near a diffuse-flow hydrothermal vent at 9°50'N on the East Pacific Rise. Upon retrieval, incubated minerals were examined by scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), X-ray diffraction (XRD), and epifluorescence microscopy (EFM). DNA was extracted from mineral samples, and the 16S ribosomal RNA gene sequenced to characterize colonizing microbes. Sulfur-oxidizing genera common to newly exposed surfaces (Sulfurimonas, Sulfurovum, and Arcobacter) were present on all samples. Differences in their relative abundance between and within incubation sites point to constraining effects of the immediate environment and the minerals themselves. Greater variability in colonizing community composition on off-vent samples suggests that the bioavailability of mineral-derived sulfide (as influenced by surface area, crystal structure, and reactivity) exerted greater control on microbial colonization in the ambient environment than in the vent environment, where dissolved sulfide is more abundant. The availability of mineral-derived sulfide as an electron donor may thus be a key control on the activity and proliferation of deep-sea chemosynthetic communities, and this interpretation supports the potential for microbial dissolution of HgS at hydrothermal vents.

Effect of Sulfate on the Migration and Transformation of Methylmercury in Advanced Anaerobic Digestion of Sludge

To study the migration and transformation of methylmercury during advanced anaerobic digestion of sludge and the role of sulfate, this study investigated the migration and transformation of methylmercury during different stages of sludge anaerobic digestion (AD) with thermal hydrolysis pretreatment and under different dosages of sulfate addition. The results showed that mercury methylation occurred in the initial stage of AD (Day 1-3), the ratio of methylmercury to total mercury increased from 0.024% (range of 0.019%-0.033%) to 0.038% (range of 0.030%-0.048%), and the net increment of methylmercury increased by 3.97, 6.09, 0.17, 3.71, and 1.66 times, respectively. In the following Day 3-5, the demethylation process occurred with the net yield of methylmercury decreased by 71.25% (ranging from 67.42% to 75.10%). Sulfate inhibited the methylation of mercury in the initial stage of AD, but had little effect on it in the late stage. This was related to the reduction of the bioavailability of neutral mercury complexes by charged groups of HgHS22- and HgS22-, as well as the immobilization of iron sulfide and mercury sulfide on S2- and bioavailable mercury. Redundancy analysis (RDA) showed that mercury methylation was affected by several factors:organic substances such as propionic acid, isobutyric acid, isovaleric acid, and Fe may promote mercury methylation, whereas protein and higher pH may be inhibitors of mercury methylation in AD of sludge.

Evaluation of phototoxicity of tattoo pigments using the 3 T3 neutral red uptake phototoxicity test and a 3D human reconstructed skin model

Phototoxicity due to dermally impregnated compounds exposed to ultraviolet radiation is associated with skin inflammation. The phototoxicity potential of active substances applied to the skin should be evaluated. Pigments are widely used for tattoos, and hypersensitivity reactions, such as photoallergic dermatitis, are possible tattoo-related complications. However, the phototoxicity of these chemicals is not well known. In this study, we evaluated the phototoxicity potential of six tattoo pigments, cadmium sulfide, carbazole, cadmium selenide, mercury (II) sulfide, chromium oxide, and cobalt aluminate, using in vitro methods—3 T3 neutral red uptake (NRU) phototoxicity test (PT) and a 3D human reconstructed skin model (EpiDerm). The validated 3 T3 NRU PT indicated the phototoxicity potential of carbazole and cadmium sulfide. The 3D human skin model confirmed that only carbazole was phototoxic. The 3 T3 NRU PT data corresponded well with those from the 3D skin model and suggested the need to employ several test systems for final phototoxicity assessment. In addition to the results obtained using 3 T3 NRU PT, further testing on 3D skin models may better reflect the bioavailability of a given chemical in the skin.

A rigorous simulation model of geothermal power plants for emission control

Geothermal power plant (GTPP) operating conditions and associated emissions mainly depend on the endogenic fluid used to generate power, and the case of GTPPs located in Tuscany (Italy) is considered in this study. Since measuring on-line the quantity of emitted pollutants is a difficult task, a process simulation model featuring all unit operations of the GTTP is developed using UniSim Design® to forecast and control pollutant emissions. An accurate identification of the thermodynamic correlation parameters for the solubility of the considered pollutants (mercury and hydrogen sulfide) in water has been performed to match literature values. A data reconciliation procedure is used to match the simulation model outcome with real measurements of two (20 MWe and 40 MWe) GTTPs. Results are fully satisfactory as the mercury emission forecasted is always slightly above the measured data, evidencing the model is conservative, and hence reliable in ensuring satisfaction of emission limits established by law. For the 20 MWe plant, the simulated total mercury emissions are 3.31 g/h exceeding the measured ones by 27%, while for the 40 MWe plant, they are 1.38 g/h above the measured ones by 4%. In addition, for the 20MWe plant, pollutants emission and net power production are both considered in a performance analysis. The worst case scenario for power generation (18.7 MW) is in summer conditions, while for pollutant emission is in winter conditions with 5.22 g/h of total mercury and 20.46 kg/h of hydrogen sulfide. Finally, energetic performances result to be independent from the environmental measures adopted.

Evaluation of Quality Characteristics of Rasa-sindoor

Background: The word Rasa-sindoor was first mentioned in Rasendra Chintamani. Rasa-sindoor is therapeutically very effective and being indicated in various diseases. It is a mercury- and sulfur-based Rasaushadhis (herbomineral/metallic preparations) prepared by the Kupi Pakva procedure. Here an attempt has been made to prepare and understand its chemical composition. Objective: To develop quality standards of Rasa-sindoor prepared as per the procedures mentioned in the Ayurvedic classics. Materials and methods: The equal quantities of purified mercury and sulfur were placed in a khalva yantra. The mixture was levigated homogeneously, until a black powder was formed. This was further levigated to obtain black, soft, lusterless fine powder like collyrium (kajjali). Then Bhavana with vatankura swaras was given and bhavita Kajjali was filed in kancha kupi. Finally, Rasa-sindoor was collected from the neck of the Kupi. Physicochemical analysis, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and atomic absorption spectroscopy (AAS) have been performed to ensure the chemical nature. Results: The chemical analysis revealed that Rasa-sindoor contains 81.7% of mercury and 14.7% of sulfur on average together with other minor elements. Particle size showed the presence of microfine particle. Rasa-sindoor is tri/hexagonal (α-form) form of mercury sulfide and the XRD of the three samples confirms this phase. Usually prepared by the Kupi Pakva procedure, the free sulfur (as is in kajjali) is completely absent in the formulation. Conclusion: The results of this study certainly can be utilized as baseline data for quality assurance of this herbomineral formulation. The preliminary profiles of Rasa-sindoor evaluated in this attempt could be used to lay down a new set of pharmacopoeial standards for further research studies.