Volatile Mercury Research Articles

Determination of Mercury with a Miniature Sensor for Point-of-care Testing.

In developing countries, subsistence gold mining entails mixing metallic mercury with crushed sediments to extract gold. In this approach, the gold-mercury amalgam is heated to evaporate mercury and obtain gold. Thus, the highly volatile mercury can be absorbed through inhalation, resulting in adverse health effects. Urinalysis can be used to detect mercury, which is excreted in urine and feces, and correlate exposure with toxic effects. The current gold standard analytical methods are based on fluorescence or inductively coupled plasma mass spectrometry methods, but are expensive, time consuming, and are not easily accessible in countries where testing is needed. In this work, we report on a miniature electrochemical sensor that can rapidly detect mercury in urine at levels well below the US Biological Exposure Index (BEI) limit of 50 ppb (μg/L). The sensor is based on a thin-film gold electrode and anodic stripping voltammetry electroanalytical approach. The sensor successfully detected mercury at trace levels in urine, with a limit of detection of ~15 ppb Hg in the linear range of 20-80 ppb. With the low-cost disposable sensors and portable instrumentation, it is well suited for point-of-care applications.

Comparative environmental impact evaluation using life cycle assessment approach: a case study of integrated membrane-filtration system for the treatment of aerobically-digested palm oil mill effluent

Aiming to mitigate wastewater pollution arising from the palm oil industry, this university-industry research-and-development project focused on the integration of serial treatment processes, including the use of moving bed biofilm reactor (MBBR), pre-treatment with sand filters and activated carbon filters, and membrane technology for aerobically-digested palm oil mill effluent (POME) treatment. To assess the potential of this sustainable alternative practice in the industry, the developed technology was demonstrated in a pilot-scale facility: four combinations (Combinations I to IV) of unit operations were developed in an integrated membrane-filtration system. Combination I includes a MBBR, pre-treatment unit comprising sand filters and activated carbon filters, ultrafiltration (UF) membrane, and reverse osmosis (RO) membrane, while Combination II excludes MBBR, Combination III excludes UF membrane, and Combination IV excludes both MBBR and UF membrane. Life cycle assessment (LCA) was performed to evaluate potential environmental impacts arising from each combination while achieving the goal of obtaining recycled and reusable water from the aerobically-digested POME treatment. It is reported that electricity consumption is the predominant factor contributing to most of those categories (50–77%) as the emissions of carbon dioxide (CO2), sulfur dioxide (SO2), nitrogen oxides, and volatile mercury during the combustion of fossil fuels. Combination I in the integrated membrane-filtration system with all unit operations incurring high electricity consumption (52 MJ) contributed to the greatest environmental impact. Electricity consumption registers the highest impact towards all life cycle impact categories: 73% on climate change, 80% on terrestrial acidification, 51% on eutrophication, and 43% on human toxicity. Conversely, Combination IV is the most environmentally-friendly process, since it involves only two-unit operations – pre-treatment unit (comprising sand filters and activated carbon filters) and RO membrane unit – and thus incurs the least electricity consumption (41.6 MJ). The LCA offers insights into each combination of the operating process and facilitates both researchers and the industry towards sustainable production.

Influence of the Arctic Sea-Ice Regime Shift on Sea-Ice Methylated Mercury Trends

Arctic sea ice regulates the air–sea exchange of volatile mercury (Hg) species like dimethylmercury (DMHg) or elemental Hg and is known to host Hg methylating microbes that produce neurotoxic and b...

Mercury as a Geophysical Tracer Gas - Emissions from the Emperor Qin Tomb in Xi\xb4an Studied by Laser Radar

Mercury is, because of its high vapor pressure and its prevalence in the atmosphere as atoms, an interesting geophysical tracer gas, also with potential archaeological applications. According to historical records dating back 2200 years, the mausoleum chamber of the “Terracotta Army Emperor” Qin in Xi´an, China, contains large amounts of liquid mercury, considered as an elixir of life at the time. We here report on measurements of the atmospheric contents of atomic mercury above the tomb mound performed with a mobile differential absorption lidar (light detection and ranging) system. Our measurements, which were performed from three different locations around the mound, indeed indicate elevated atmospheric mercury levels, with localizations, which correlate with previous in situ soil sampling results. Concentrations up to 27 ng/m3 were observed, significantly higher than the typical general pollutant level in the area which was found to be around 5–10 ng/m3. An out-flux of about 5×10−8 kg/s was estimated. Highly volatile mercury may be escaping through cracks, which developed in the structure over time, and our investigation supports ancient chronicle records on the tomb, which is believed never to have been opened/looted. Our findings also have bearings on the proposed use of mercury as a tracer gas for valuable ores and geothermal resource exploration, and also bring problematics around reliable nuclear waste long-term underground storage to mind.

Determination of ultra-low volatile mercury concentrations in sulfur-rich gases and liquids

Determining mercury (Hg) concentrations in a wide range of naturally occurring liquids (i.e., groundwater, hydrothermal fluids, acid mine drainage, submarine groundwater discharge, etc.) and gases, (i.e., volcanic and hydrothermal emissions, flue gas, natural gas, land fill gas, etc.) has obstacles due to the presence of H2S in many of such samples. The classical approach of trapping Hg on gold traps comes up against its limits due to “poisoning” of the traps by H2S and problems for its determination by cold vapor atomic fluorescence spectrometry (CV-AFS). Due to low concentrations of Hg in these sample types it is often necessary to collect large amounts of liquid or gas in excess of 20 L, which makes transport to the laboratory difficult. With this in mind we developed a portable method for the collection of Hg from gases and liquids rich in H2S.The method uses an impinger set-up with an alkaline trap followed by two potassium permanganate - sulfuric acid traps. The potassium permanganate (KMnO4) oxidizes elemental Hg vapor to Hg2+, which remains in the KMnO4 solution and thus can be analyzed by CV-AFS. Thus, rather than 25 L of sample, only a few mL have to be transported to the laboratory. A possible caveat of this approach is that naturally occurring gases are generally a mixture of several different gases, such as H2, CH4, SO2 and H2S, which can react with and thus consume KMnO4. The influence of various gas compounds at different concentrations were tested for their effect on the trapping of Hg by KMnO4. Hydrogen and CH4 did not cause any interference, while SO2 did react with the KMnO4. When the oxidizing capacity in the first KMnO4-trap was depleted due to SO2, Hg was trapped in the second KMnO4-trap, which acted as a safety trap. Good recoveries of 99.5 % were achieved for the Hg collected in both KMnO4-traps. Nevertheless, when H2S was introduced into the system, Hg recovery dropped by almost 50 %. This observation was attributed to the formation of mercury sulfide (HgS) in the trap when the oxidation capacity of the KMnO4-trap was consumed. HgS cannot be reduced by stannous chloride (SnCl2), which is necessary for detection by CV-AFS. The problem was overcome by adding an alkaline trap with the reductant sodium borohydride (NaBH4) in front of the two KMnO4-traps. In this trap H2S was converted to S2-, which does not reach the KMnO4-trap while at the same time NaBH4 prevented the oxidation of Hg to Hg2+ followed by precipitation as HgS. Good recoveries of 98.05 ± 3.6 % (n = 3) were obtained for Hg when a volume of 1000 mL H2S was passed through the impinger train.Field testing of the method verified the effect of H2S on the trapping and ultimately the determination of Hg in the hydrothermal gas. With the alkaline trap we determined a Hg concentration of 358 ng m−3 Hg, while without the alkaline trap only 101 ng m−3 Hg. Thus, the set-up without the alkaline trap led to an underestimation of the real Hg concentration by 71.8 % and confirmed the necessity of an alkaline trap to overcome the interference of H2S.

Elemental mercury oxidation over manganese oxide octahedral molecular sieve catalyst at low flue gas temperature

Manganese oxide octahedral molecular sieve (OMS-2) with cryptomelane structure synthesized by a solvent-free method was employed to oxidize gaseous elemental mercury (Hg0) in coal combustion flue gas for the first time. Brunauer-Emmett-Teller (BET) surface area analysis, X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectra, H2 temperature-programmed reduction (H2-TPR) and X-ray photoelectron spectroscopy (XPS) measurement were employed to characterize the catalyst. The OMS-2 with large surface area and abundant pores presented excellent Hg0 oxidation performance at a wide temperature range of 100–250 °C. At the optimal operating temperature of 150 °C, 93% Hg0 oxidation efficiency was obtained under a gas hourly space velocity as high as 1,350,000 h−1. Hg0 oxidation on OMS-2 catalyst was supposed to follow the Mars-Maessen mechanism, where the gaseous Hg0 was firstly adsorbed on the OMS-2 catalyst surface to form adsorbed Hg0, and then the adsorbed Hg0 was oxidized by the lattice oxygen over catalyst surface to form mercury oxide (HgO). Both HCl and NO in the flue gas promoted Hg0 oxidation mainly due to the formation of active species like Cl∗, NO2, which reacted with Hg0 to form volatile mercury species. SO2 inhibited the Hg0 oxidation by reducing the adsorbed HgO into gaseous Hg0 or generating sulfate on the catalyst surface. Water vapor also played an inhibitive role in Hg0 oxidation. However, the SO2 and H2O resistance of OMS-2 catalyst was much superior compared to other commercial catalysts, which makes it promising for industrial application. This knowledge is beneficial for developing economical and efficient Hg0 oxidation catalysts for coal-fired power plants.

Measuring and Mitigating Mercury Gases in the Museums Victoria Collection.

For the past six years the conservation and collection management departments at Museums Victoria have been conducting a major survey to determine the type and extent of hazardous substances in the collections to better inform safe handling and storage practices. This paper focuses on mercury compounds in the collection, including mercury chloride applied as a pesticide, mercury sulfide pigments, liquid mercury used in scientific equipment, and mineral specimens such as native mercury and cinnabar. All these compounds can release volatile mercury vapour into storage furniture and have the potential to contaminate both the cabinet and other specimens stored nearby. Although previous testing had confirmed that the air in storage rooms and workspaces contained no detectable levels of mercury vapour, recent publications by Hawks et al. 2004, Havermans et al. 2015 and Marcotte et al. 2017 showing high levels of mercury vapour inside storage containers in herbaria raised concern that there could be higher than acceptable levels of mercury vapour building up inside storage cabinets at Museums Victoria. This prompted analysis of the headspace in cabinets using a Jerome J405 portable mercury vapour meter. Testing was informed by the results of previous hazards surveys using X-ray fluorescence spectrography to target cabinets where mercury vapour was likely to be present. Air from cabinets was sampled across the indigenous cultures, history, technology and natural sciences collections. Results showed levels of mercury vapour could be considerably above 25 μg/m3 the Australian time-weighted average (TWA) exposure standard for an 8 hour workday in cabinets of bird skins and indigenous artefacts treated with mercuric chloride pesticides. Results above 150 μg/m3 the temporary emergency exposure level (TEEL) were measured in the mineralogy collection. Mitigation strategies are being implemented to reduce the risks to staff health and contamination of other collection materials, including enclosing mercury-containing species of minerals in gas barrier film, venting high risk cabinets to dissipate vapour before accessing specimens, and engineering controls during the handling of specimens.

Study on Mercury Distribution and Speciation in Urban Road Runoff in Nanjing City, China

The current study was aimed to investigate the mercury pollution in urban road runoff. A total of 34 rainfall events were monitored on 5 independent road catchments from 2015 to 2016 in Nanjing city, China. Events mean concentrations of mercury and the impact factors of mercury pollution in urban road runoff were also carried out in the current study. Results revealed that the concentration of various mercury species was very high. Total mercury, dissolved mercury and particulate mercury were found to be in the range of 0.173–8.254 μg/L, 0.069–6.823 μg/L, and 0.086–2.485 μg/L, respectively. The order of total mercury concentration among the five catchments was as follows: Longpan road > Xinjiekou > Jiulonghu > Zhujiang road > Maqun area. Results revealed the existence of different dominant species of mercury in different urban areas. Particularly, mercury in urban road runoff mainly existed in particulate form in Maqun area, and the concentrations of inactive mercury (0.250–2.821 μg/L) were far more than that of volatile mercury (0.023–0.215 μg/L) and active mercury (0.026–0.359 μg/L). The order of impact factors of rainfall characteristics on Hg pollution in runoff was dry periods > runoff time > duration of rainfall > storm intensity > rainfall. Analysis based on the first flush effect showed that the first flush phenomenon of mercury was not significant.

Mercury speciation by differential photochemical vapor generation at UV-B vs. UV-C wavelength

Photochemical vapor generation (PVG) is an effective sample introduction scheme for volatile mercury (Hg). Speciation of Hg++ and MeHg+ was fulfilled for the first time by differential PVG under UV-B vs. UV-C wavelength and applied to fish oil supplements. After liquid-liquid extraction, the aqueous extract was mixed with 0.4% anthranilic acid (AA)-20% formic acid (FA) in a quartz coil, and exposed sequentially to 311nm or 254nm UV light. The resulting Hg0 vapor was detected by atomic fluorescence spectrometry (AFS). At each wavelength, the AFS intensity was a linear function of Hg++ and MeHg+ concentrations, which were solvable from a set of two equations. This method achieved ultrahigh sensitivity with 0.50 and 0.63ngmL−1 limits of detection for Hg++ and MeHg+, respectively, and 73% recovery for MeHg+ at 10ngmL−1. Validation was performed by ICP-MS on total Hg. Obviation of chemical or chromatographic separation rendered this method rapid, green, and cost-effective.

The history of silver refining in New Spain, 16c to 18c: back to the basics

The refining of silver ores in New Spain was defined by the chemical nature of the silver ore. Argentiferous galena (lead sulphide) could only be refined by smelting (36% silver produced), irrespective of silver content, and amalgamation (64%) could only be applied to the silver sulphide ores. Both processes were transferred from Europe, but amalgamation was transformed by local expertise from a recipe of limited application to an industrial-scale solution for refining sulphidic silver ores. Its implementation shaped the environmental history of colonial silver refining in the New World. Mercury was consumed mainly through its chemical conversion into calomel, with minimal emissions of volatile mercury. Waste silt and liquid mercury in the soil and waterways were its main legacy. Smelting created a greater impact on the environment of New Spain, via lead in lead fumes as the main heavy metal issued to the air, and its depletion of woodlands. This article argues that a technical analysis of period refining practices in New Spain reorients our understanding of Spain’s imperial relations with its New World colonies, of the role of local knowledge in a global economy of silver production, and of environmental issues in colonial history. It thus speaks to the problem of unpacking the complex web of relations that composed early European imperialism, in which were enmeshed commodities such as silver, cotton and sugar.

Removal of Mercury from Wastewater Using a Constructed Wetland

Removal of mercury from municipal wastewater using a constructed wetland was studied. Wastewater, wetland plant, and sediment samples were analyzed using an advanced mercury analyzer AMA-254. Average concentrations of total mercury in inflow and outflow water were 0.157 and 0.057 μg L−1, respectively. Significant fraction of mercury (38.2 %) was removed from wastewater during pretreatment. Mercury concentrations in vegetation (Phragmites australis) varied in the range of 0.0099−0.0105 and 0.0079−0.0086 mg kg−1 for the above and belowground biomass, respectively. Total mercury concentrations in the constructed wetland sediments were 0.151 and 0.103 mg kg−1 at distances 1 and 10 m from the inflow zone. Mercury can be precipitated and deposited at the initial part of the wetland bed and thus removed from wastewater. The formation of volatile mercury species is another mechanism of its removal. On the other hand, assimilation of Hg in wetland plants does apparently not contribute to mercury removal from wastewater.

The distribution and sea–air transfer of volatile mercury in waste post-desulfurization seawater discharged from a coal-fired power plant

The waste seawater discharged in coastal areas from coal-fired power plants equipped with a seawater desulfurization system might carry pollutants such as mercury from the flue gas into the adjacent seas. However, only very limited impact studies have been carried out. Taking a typical plant in Xiamen as an example, the present study targeted the distribution and sea-air transfer flux of volatile mercury in seawater, in order to trace the fate of the discharged mercury other than into the sediments. Samples from 28 sampling sites were collected in the sea area around two discharge outlets of the plant, daily and seasonally. Total mercury, dissolved gaseous mercury and dissolved total mercury in the seawater, as well as gaseous elemental mercury above the sea surface, were investigated. Mean concentrations of dissolved gaseous mercury and gaseous elemental mercury in the area were 183 and 4.48ngm(-3) in summer and 116 and 3.92ngm(-3) in winter, which were significantly higher than those at a reference site. Based on the flux calculation, the transfer of volatile mercury was from the sea surface into the atmosphere, and more than 4.4kg mercury, accounting for at least 2.2% of the total discharge amount of the coal-fired power plant in the sampling area (1km(2)), was emitted to the air annually. This study strongly suggested that besides being deposited into the sediment and diluted with seawater, emission into the atmosphere was an important fate for the mercury from the waste seawater from coal-fired power plants.

A Wet and Volatile Mercury

Observations by the MESSENGER spacecraft are revealing details of Mercury's dynamic atmosphere. [Also see Reports by Lawrence et al. , Neumann et al. , and Paige et al. ]

The extent of the influence and flux estimation of volatile mercury from the aeration pool in a typical coal-fired power plant equipped with a seawater flue gas desulfurization system

Before being discharged, the waste seawater from the flue gas desulfurization system of coal-fired power plants contains a large amount of mercury, and is treated in aeration pools. During this aeration process, part of the mercury enters the atmosphere, but only very limited impact studies concerning this have been carried out. Taking a typical Xiamen power plant as an example, the present study targeted the elemental mercury emitted from the aeration pool. Concentrations of dissolved gaseous mercury as high as 1.14±0.17ng·L−1 were observed in the surface waste seawater in the aeration pool, and gaseous elemental mercury (GEM) as high as 10.94±1.89ng·m−3 was found in the air above the pool.To investigate the area affected by this GEM through air transfer, the total mercury in the dust and topsoil samples around the aeration pool were analyzed. Much higher values were found compared to those at a reference site. Environmental factors other than solar radiation had limited influence on the concentrations of the mercury species in the pool. A simulation device was built in our laboratory to study the flux of mercury from the aeration pool into the air. The results showed that more than 0.59kg of mercury was released from the aeration pool every year, occupying 0.3% of the total mercury in the waste seawater. The transfer of mercury from water to air during the aeration pool and its environmental influence should not be ignored.

Assessment of environmental mercury discharge at a four-year-old artisanal gold mining area on Lombok Island, Indonesia

Indonesian artisanal and small-scale gold mining activities (ASGM) have been described for the islands of Borneo (Kalimantan) and Sulawesi. But the increased gold price over recent years has seen operations extend to the islands of Lombok and Sumbawa. For the current research, an environmental assessment was conducted across three new ASGM locations. Gold is recovered by miners through a two-stage process of whole-ore amalgamation and cyanidation. Waste (tailings) is discharged to land or sea with no concern for contaminants in the tailings. The gold grade of ore is up to 5000 mg kg(-1). The mean gold grade of the amalgamation tailings is 7 mg kg(-1), dropping to 1.2 mg kg(-1) for the cyanidation tailings. The mean mercury concentration of the amalgamation tailings is about 3000 mg kg(-1) and greater than 1600 mg kg(-1) for the cyanidation tailings. Samples of paddy rice grain collected adjacent to cyanidation tailings ponds showed methyl mercury concentrations greater than 100 ng g(-1). This is five times above the Chinese permissible level for total mercury in food crops. The mean total mercury concentration in hair of Lombok ASGM workers was greater than that in a non-exposed population; however there was no difference in methyl mercury concentration. This indicates the primary pathway of mercury exposure is inhalation of volatile mercury in the atmosphere. Future exposure may come from ingestion of methyl mercury contaminated rice where discharge of cyanide tailings to paddies continues. To protect the environment and to enhance the sustainability of ASGM, appropriate tailings management must be implemented. The gold grade of the tailings indicates that the residual value might be recoverable with appropriate technology. Ongoing research is investigating systems such as phytoextraction that might assist ASGM operators in Lombok and Sumbawa to improve their environmental performance.

Air–sea exchange of volatile mercury in the North Atlantic Ocean

Part of the Beringia 2005 expedition covered the North Atlantic Ocean. During this passage, dissolved gaseous mercury (DGHg) in seawater and atmospheric concentrations of total gaseous mercury (TGHg), carbon monoxide (CO), and ozone (O 3) were measured continuously at high resolution. In addition, meteorological parameters such as wind speed and water temperature were measured continuously by the ship's meteorological instrumentation. The DGHg concentration was measured using a continuous equilibrium system where the elemental mercury in the sea water was equilibrated with a stream of gas. The DGHg concentration was calculated using DGHg = Hg eq/k H′ where Hg eq is the concentration of elemental mercury in the equilibrated air and k H′ is the dimensionless Henry's law constant. The degree of saturation was determined directly from the measurements S = Hg eq/TGHg. The water sampled had an average DGHg concentration of 58 ± 10 fM and the average TGHg concentration was determined to 1.7 ± 0.1 ng m − 3 . The water sampled was under- and super-saturated with respect to elemental mercury covering a large range of saturation of 70 to 230% resulting in an average degree of saturation of 150 ± 30%. Therefore, both evasion and deposition of elemental mercury were observed in the sampled water. In the light of the average flux, 2.1 ± 1.8 pmol m −2 h − 1 , it is concluded that mostly evasion occured during the sampling period.

ChemInform Abstract: Application of Mercury‐Resistant Genes in Bioremediation of Mercurials in Environments

AbstractReview: 77 refs.

Application of Mercury-resistant Genes in Bioremediation of Mercurials in Environments

Mercury and its organic compounds, especially methylmercury are extremely hazardous pollutants that have been released into the environment in substantial quantities by natural events and anthropogenic activities. Due to the acute toxicity of these contaminants, there is an urgent need to develop an effective and affordable technology to remove them from the environments. Recently, attempts have been made to utilize bacterial mer operon-mediated reduction and volatilization of mercurials for environmental remediation of mercury pollution. However, application of this technology to the treatment of mercury-contaminated environments has been limited by social concerns about the release of volatile mercury that will become part of the local mercury cycle and repollute the environment again, into the ambient air. To improve this environmental problem, a new mercury scavenging mechanism that could be expressed in living cells and accumulates mercury from contaminated site without releasing mercury vapor is necessitated. To construct a new biocatalyst that is capable of specifically accumulating mercury from contaminated sites without releasing mercury vapor, we have genetically engineered bacteria and tobacco plant for removal of mercury from wastewater and soils, respectively, to express a mercury transport system and organomercurial lyase enzyme simultaneously, and overexpress polyphosphate, a chelator of divalent metals. The applicability of these new engineered biocatalysts in the environmental remediation of mercurials is evaluated and discussed in this review.

Capture of Volatile Mercury with a Gold Needle and its Application to Geothermal Prospecting

Capture of Volatile Mercury with a Gold Needle and its Application to Geothermal Prospecting

Historical accumulation rates of mercury in four Scottish ombrotrophic peat bogs over the past 2000 years

The historical accumulation rates of mercury resulting from atmospheric deposition to four Scottish ombrotrophic peat bogs, Turclossie Moss (northeast Scotland), Flanders Moss (west-central), Red Moss of Balerno (east-central) and Carsegowan Moss (southwest), were determined via analysis of 210Pb- and 14C-dated cores up to 2000 years old. Average pre-industrial rates of mercury accumulation of 4.5 and 3.7 μg m − 2 y − 1 were obtained for Flanders Moss (A.D. 1–1800) and Red Moss of Balerno (A.D. 800–1800), respectively. Thereafter, mercury accumulation rates increased to typical maximum values of 51, 61, 77 and 85 μg m − 2 y − 1 , recorded at different times possibly reflecting local/regional influences during the first 70 years of the 20th century, at the four sites (TM, FM, RM, CM), before declining to a mean value of 27 ± 15 μg m − 2 y − 1 during the late 1990s/early 2000s. Comparison of such trends for mercury with those for lead and arsenic in the cores and also with direct data for the declining UK emissions of these three elements since 1970 suggested that a substantial proportion of the mercury deposited at these sites over the past few decades originated from outwith the UK, with contributions to wet and dry deposition arising from long-range transport of mercury released by sources such as combustion of coal. Confidence in the chronological reliability of these core-derived trends in absolute and relative accumulation of mercury, at least since the 19th century, was provided by the excellent agreement between the corresponding detailed and characteristic temporal trends in the 206Pb/ 207Pb isotopic ratio of lead in the 210Pb-dated Turclossie Moss core and those in archival Scottish Sphagnum moss samples of known date of collection. The possibility of some longer-term loss of volatile mercury released from diagenetically altered older peat cannot, however, be excluded by the findings of this study.