Mercury Release Research Articles

Anthropogenic Mercury Release Flow in China

China is the largest emitter of anthropogenic mercury worldwide. Implementation of the Minamata Convention on Mercury will significantly impact the development, use, and management of mercury resources. Chinese mercury management policies require significant adjustment. There is an urgent need to develop a current national mercury inventory to estimate mercury inputs and outputs by source category, and to clarify the distributions to various environmental scenarios. Here, the mercury releases are quantitatively analysed to facilitate the implementation of strategic mercury management policies in China. First, the mercury inputs and outputs by source categories in 2016 are quantified and then the mercury distributions to various environmental and intermediate sinks are estimated. The total mercury input was 5,116 t in 2016, of which 77% was attributable to mineral production. In total, 3,083 t were released into various environmental and intermediate reservoirs. Of this total, 53.8 % was intentional uses, followed by extraction and combustion (26.5%), and mineral production (19.6 %); 1,501 t were released into air, water, and land, of which extraction and combustion accounted for 48.6 % followed by mineral production (25.7 %) and intentional uses (25.6 %).

Mercury and Alzheimer's disease: a look at the links and evidence.

This review paper investigates a specific environmental-disease interaction between mercury exposure and Alzheimer's disease hallmarks. Alzheimer's disease is a neurodegenerative disorder affecting predominantly the memory of the affected individual. It prevails mostly in the elderly, rendering many factors as possible causative agents, which potentially contribute to the disease pathogenicity cumulatively. Alzheimer's disease affects nearly 50 million people worldwide and is considered one the most devastating diseases not only for the patient, but also for their families and caregivers. Mercury is a common environmental toxin, found in the atmosphere mostly due to human activity, such as coal burning for heating and cooking. Natural release of mercury into the atmosphere occurs by volcanic eruptions, in the form of vapor, or weathering rocks. The most toxic form of mercury to humans is methylmercury, to which humans are exposed to by ingestion of fish. Methylmercury was found to exert its toxic effects on different parts of the human body, with predominance on the brain. There is no safe concentration for mercury in the atmosphere, even trace amounts can elicit harm to humans in the long term. Mercury's effect on Alzheimer's disease hallmarks formation, extracellular senile plaques and intracellular neurofibrillary tangles, has been widely studied. This review demonstrates the involvement of mercury, in its different forms, in the pathway of amyloid beta deposition and tau tangles formation. It aims to understand the link between mercury exposure and Alzheimer's disease so that, in the future, prevention strategies can be applied to halt the progression of this disease.

Artisanal and small-scale gold mining activities and mercury exposure in Gorontalo Utara Regency, Indonesia

Small-scale gold mining activities and their mercury emissions in the Gorontalo Utara Regency of the Gorontalo Province, Sulawesi Island, Indonesia, have been studied. The mining occurs in many areas of this region, but especially in the three villages Hulawa, Ilangata and Ilangata Barat. Mining activities in the Hulawa village are the oldest (19th century) in the regency, whereas mining in the Ilangata village began just 15 years ago. The activity level changes rapidly from time to time depending on the fluctuations of the gold market. Women and children are involved in the gold mining process. Female workers crush ore, process sediment wastes, and pan for gold in rivers. Children assist their mothers in these activities and play around the mining sites. Gold mining in the Utara Regency is estimated to produce about 290 kg of gold and emits approximately 860 kg of mercury into the environment annually. The impact of such large mercury release into the environment have caused environmental degradation and contamination of fish as food for humans. Collaborative works of stakeholders are urgently needed to find solutions to the problems related to small-scale gold mining such as marginalization and environmental pollution.

Semiconducting Polymer Interfaces for Electrochemically Assisted Mercury Remediation.

Nanostructured polymer interfaces can play a key role in addressing urgent challenges in water purification and advanced separations. Conventional technologies for mercury remediation often necessitate large energetic inputs, produce significant secondary waste, or when electrochemical, lead to strong irreversibility. Here, we propose the reversible, electrochemical capture and release of mercury, by modulating interfacial mercury deposition through a sulfur-containing, semiconducting redox polymer. Electrodeposition/stripping of mercury was carried out with a nanostructured poly(3-hexylthiophene-2,5-diyl)-carbon nanotube composite electrode, coated on titanium (P3HT-CNT/Ti). During electrochemical release, mercury was reversibly stripped in a non-acid electrolyte with 12-fold higher release kinetics compared to nonfunctionalized electrodes. In situ optical microscopy confirmed the rapid, reversible nature of the electrodeposition/stripping process with P3HT-CNT/Ti, indicating the key role of redox processes in mediating the mercury phase transition. The polymer-functionalized system exhibited high mercury removal efficiencies (>97%) in real wastewater matrices while bringing the final mercury concentrations down to <2 μg L-1. Moreover, an energy consumption analysis highlighted a 3-fold increase in efficiency with P3HT-CNT/Ti compared to titanium. Our study demonstrates the effectiveness of semiconducting redox polymers for reversible mercury deposition and points to future applications in mediating electrochemical stripping for various environmental applications.

The influence of legacy contamination on the transport and bioaccumulation of mercury within the Mobile River Basin

Past industrial use and subsequent release of mercury (Hg) into the environment have resulted in severe cases of legacy contamination that still influence contemporary Hg levels in biota. While the bioaccumulation of legacy Hg is commonly assessed via concentration measurements within fish tissue, this practice becomes difficult in regions of high productivity and methylmercury (MeHg) production, like the Mobile River Basin, Alabama in the southeastern United States. This study applied Hg stable isotope tracers to distinguish legacy Hg from regional deposition sources in sediments, waters, and fish within the Mobile River. Sediments and waters displayed differences in δ202Hg between industrial and background sites, which corresponded to drastic differences in Hg concentration. Sites that were affected by legacy Hg, as defined by δ202Hg, produced largemouth bass with lower MeHg content (59–70%) than those captured in the main rivers (>85%). Direct measurements of Hg isotopes and mathematical estimates of MeHg isotope pools in fish displayed similar distinctions between legacy and watershed sources as observed in other matrices. These results indicate that legacy Hg can accumulate directly into fish tissue as the inorganic species and may also be available for methylation within contaminated zones decades after the initial release.

Analysis of mercury concentration in former mine areas in Slovakia

Abstract Background Mercury is ubiquitous in the biosphere, occurring in the air, water, land, and soil, as well as in the living organisms. Mercury release in the environment is mainly the result of human activity, particularly from coal-fired power stations, waste incinerators and as a result of mining for mercury and other metals, which have led to wide spread global mercury pollution. The excessive exposure to mercury is a public health concern since it is associated with a wide range of adverse health effects including damage to the central nervous system and the kidneys. Mercury poses a threat to the development of the child in utero and early in life. We answer the question whether the monitoring of mercury is important even though the ore processing factories ended their production. Methods A total of 5,579 samples of foodstuffs from food retails in Slovakia and 24 species of plants within 100 meters to the former ore processing factory in Eastern Slovakia have been collected over the last two decades. The samples were selected randomly and the material was homogenized. Atomic absorption spectrometry standard solutions for mercury were used at a wavelength of 254 nm. Results The maximum mercury level set by the European Commission Regulation was exceeded in 314 samples. 50.52% of the total 384 fish samples from food retails in Slovakia were above the limit. The concentrations of mercury in the plants and in the soils taken to a depth of 0.25 m exceeded the maximum levels more than 6-times and 50-times, respectively. Conclusions The acceptance of mercurýs environmental impacts require several decades of research and public health activities. The monitoring of mercury worldwide is important, since we found that the end of ore processing does not solve the issue of contamination. We recommend developing procedures and legislation for the consumption of selected foods from the areas of ore processing companies for children, adolescents, pregnant women and nursing mothers. Key messages The systematic monitoring of mercury is still very important, since we found that the end of ore processing does not solve the issue of contamination in the former ore processing areas. It is not recommend the consumption of selected foods and plants from the former ore processing areas for selected groups of the population – children, pregnant women and nursing mothers.

Luminescent metal organic framework for selective detection of mercury in aqueous media: Microwave-based synthesis and evaluation

Mercury is one of the most hazardous environmental pollutants due to its immediate health implications on humans. With pollution risks of water bodies due to industrial and natural release of mercury, there is a need to assess the contamination of sea water to ensure its safety and sustainability to effectively prevent health deterioration due to mercury absorption through seafood consumption. Metal organic frameworks (MOFs) have emerged as a new class of crystalline porous materials with potential deployment for chemical detection thanks to their outstanding features including high specific surface areas, tunable pore size, and easy functionalization of the organic part upon selection of different metal ions and organic bridging ligands. In the present study, a novel MOF namely NH2-Cd-BDC was successfully developed and investigated toward mercury detection in a competitive aqueous medium in presence of other metal ions. NH2-Cd-BDC is composed of Cadmium ions (Cd2+) as the metal cluster and 2-aminoterephthalic acid (NH2-H2BDC) as the organic linker. The luminescent property of the MOF provides a cost-effective and nondestructive method for testing the detection ability of the MOF using fluoro-spectroscopy. The experiments showed that the developed MOF has a limit of detection of 0.58 μM and demonstrated the superiority of mercury detection in comparison to other metal ions including Na+, K+, Ca2+, Cr3+, Cd2+, Cu2+, Pb2+ and Fe3+. Several characterization tests of the novel developed MOF were executed including XRD, FTIR, TGA, FE-SEM and SEM to inspect its crystalline structure and thermal stability. The experimental study revealed that the MOF has a crystalline sea-shell shape, providing a large pore size for the mercury to be trapped in.

Study on Mercury Species in Coal and Pyrolysis-Based Mercury Removal before Utilization.

Coal-fired mercury (Hg) pollution control is an important global environmental context. Eight coal samples from different coal fields in China were used to investigate Hg species and the Hg removal effects under different pyrolysis conditions in the presence of nitrogen. These conditions included temperature, particle size, and residence time. The study concludes that the temperature is the most important factor affecting Hg removal from coal, and the mercury release activity at specific temperatures depends on the species and content of Hg present. Large particle size limits the removal rate of Hg, and coal particles smaller than 40 mesh are more favorable for the rapid removal of Hg. For most coal types, pyrolysis of 10–15 min can achieve the ultimate Hg removal effect. Rapid pyrolysis at 600 °C in nitrogen is feasible to remove Hg from coal. Consequently, the Hg removal rate reaches 88–100%, the loss rate of coal calorific value is 2–12%, and approximately 17–58% of S is removed synergistically. HgS, HgSe, HgSO4, organic matter Hg, and HgO are the main types of Hg species detected in coal, whose thermal decomposition characteristics are the essential criteria for determining the type of Hg removal process. This research will facilitate the improvement of pollution control methods for coal-source Hg pollution.

Mercury release from a two surface amalgam restoration

Mercury release from a two surface amalgam restoration

Changes in surface water quality from small-scale gold mining operations in the Surinamean rainforest

Small-scale miners often engage in environmentally damaging activities, are subject to poor safety conditions, and utilize inefficient mineral extraction technologies. Here, we explore environmental impacts to surface waters from regional artisanal small-scale gold placer mining operations conducted in iron and aluminum-rich saprolites found within the lateritic, interior Amazon rainforest of Suriname. Heavy equipment was utilized to release gold from its host material followed by amalgamation and gravity separation. In contrast with background tributary recordings, streams adjacent to these gold mining operations consistently contained turbidity measurements that exceeded United States’ EPA guidelines for aquatic species of 50 nephelometric turbidity units and were typically in the hundreds to thousands of units. Turbidity was further heightened in association with precipitation events. Mercury played a prominent role in whole ore amalgam concentration practices. Freshwater fish from the region were found to harbor mercury that encroached upon public health criteria. Dissolved phase metals present further ecotoxicological challenges to the region, but their association with mining activities was less clear. These findings collectively reveal that small-scale placer gold mining practices in the Surinamese rainforest result in an increase of suspended sediments and release of mercury into waterways that could impact communities that depend upon local fisheries.

Mercury in the sediments of freshwater lakes in Ny-Ålesund, Arctic.

Mercury and its speciation in aquatic ecosystems have been assessed globally. Even though previous studies were limited to Arctic freshwater lakes, they are highly significant in the context of the changing climate. The present study is based on sediment samples collected from three Arctic freshwater lakes over a period of 4years (2015-2018). The samples were analysed for total mercury (THg), methyl mercury (MHg), and various mercury fractions. The observed mean THg and MHg concentrations were 22.23ng/g and 0.41ng/g respectively; these values were comparable with those for other Arctic freshwater lakes. The mercury content significantly varied among the years as well as among the lakes. Changes in snowdrift and meltwater inputs, which are the major sources of water for the lakes, may have influenced the sediment mercury content along with geographical location and increased productivity. The results of MHg indicated the susceptibility of lake sediments to methylation. The major fractions observed were the organo-chelated form of mercury, followed by the elemental and water-soluble forms. These results indicate the availability of mercury for methylation. Hence, it is necessary to conduct more studies on the influence of climate change, mercury release through permafrost melting, and atmospheric deposition.

Evaluation of mercury release from dental amalgam after cone beam computed tomography and magnetic resonance imaging with 3.0-T and 1.5-T magnetic field strengths

This in vitro study aimed to investigate leakage of mercury from amalgam restorations after cone beam computed tomography (CBCT) and magnetic resonance imaging (MRI) examinations. In total, 238 amalgam disks were prepared and placed in saline solution. The samples were allocated randomly to 7 groups, with 34 samples in each group. CBCT imaging was performed for 4 groups with different imaging parameters (narrow/wide field of view [FOV]; standard/high-resolution). MRI procedures were performed with 3.0-T and 1.5-T magnetic field strengths. No imaging was performed for the samples in the control group. The amalgam samples were removed from the tubes 24 hours after imaging and submitted for plasma mass spectrometry analysis. Kruskal-Wallis and Dunn's tests were performed to compare data. A P value less than .05 was accepted as statistically significant. The highest mean mercury value was found in the 3.0-T MRI group, whereas the lowest mean value was found in the narrow FOV, standard-resolution CBCT group. There were no significant differences between the control group and the experimental groups (P ≥ .338) or between the experimental groups (P > .05). CBCT and MRI procedures similar to those used in patient care caused no significantly different mercury release compared with nonexposed samples.

Total and Methylmercury of Suaeda heteroptera Wetland Soil Response to a Salinity Gradient Under Wetting and Drying Conditions.

Mercury (Hg) methylation could occur in freshwater ecosystems with low or high salinity. However, few studies are available about the effects of salinity change on mercury(Hg) release and methylation. In-situ experiments using Suaeda heteroptera wetland soil column from the Liaohe estuary were performed to decipher how total mercury (THg) and methylmercury (MeHg) contents change under fluctuant salinity and wet and dry soil conditions. Salinity gradients were set to 0.50% (S1), 1.00% (S2), 1.50% (S3) and 1.80% (S4), and pure deionized water was used as a blank control (CK). Wet and dry soil conditions were set to full inundation condition (WD1) and naturally dried treatment (WD2). Results indicated that the highest THg and MeHg contents were found in surface and bottom soil when water salinity treatment was CK under WD1. THg and MeHg decreased with salinity under WD1. THg contents in overlying water varied from 0.854 to 1.243µg L-1 under WD1 treatments and increased with salinity change. When under WD2 treatment, THg contents in both soil layers gradually decreased with rising salinity. Meanwhile, MeHg contents in both soil layers reached the lowest level at CK (1.666μg kg-1and 2.520μg kg-1) and increased gradually with the rising salinity. By comparison, THg content of the soil was much lower in WD1 than that in WD2. Under the WD1 condition, the MeHg contents and %MeHg decreased with rising salinity and showed significantly different in different salinity treatment, however, its showed an opposite trend with rising salinity under the WD2 condition.

Release characteristics of mercury in chemical looping combustion of bituminous coal

This study evaluated the release characteristics of mercury from bituminous coal in chemical looping combustion (CLC) using Australian iron ore as the oxygen carrier in a fixed bed reactor. The effects of several parameters, such as temperature in the fuel reactor (FR) and air reactor (AR), gasification medium in the FR, and reaction atmosphere in the AR, on mercury release characteristics, were investigated. The mercury speciation and release amount in the FR and AR under different conditions were further explored. The results indicate that most of the mercury in coal was released in the FR, while the rest of it was released in the AR. Hg0 was found to be the major species in the released mercury. The results also indicate that a higher temperature in the FR led to an increase in the total mercury release amount and a decrease in Hg0 proportion. However, a higher temperature in the AR resulted in a decrease in the total mercury release amount and Hg0 proportion. The increase in the H2O/CO2 ratio of gasification mediums in the FR was beneficial for the increase in the total mercury release amount and Hg0 proportion. A higher O2 concentration in reaction atmosphere in AR had a negligible effect on the total mercury release amount, but a positive effect on Hg0 oxidization.

Heavy metals in alluvial gold mine spoils in the peruvian amazon

Alluvial gold mining in the Peruvian Amazon has become a key driver of land degradation and deforestation. The associated release of mercury in the environment poses direct human health risks and is likely to engender cascading effects throughout local food chains. We carried out research in an alluvial gold mine concession in the Madre de Dios region to compare the degree of soil-borne pollution of heavy metals in areas where mining operations were abandoned more and less recently (1–5 and 6–8 years ago, respectively) with non-impacted old-growth forest areas. All heavy metals, were below permissible levels according to Peruvian and Canadian environmental quality standards. Mean As, Ba, Pb, Cu, Cr, Ni, V and Zn concentrations in impacted areas were 1.90 ± 1.51, 29.80 ± 22.87, 4.60 ± 2.55, 12.68 ± 8.13, 7.90 ± 3.98, 7.93 ± 3.89, 12.67 ± 6.62, and 26.65 ± 13.53 mg kg−1 dry matter (DM), respectively. Heavy metal concentrations were higher in non-impacted old growth forest soils than in mining spoils, and tended to increase with time since abandonment of mining operations. Hg was not detected in any of the sites. Low heavy metal concentrations in mine spoils might beexplained because of intense volatilization, reduced metal retention capacity due to the low clay and organic matter content, and leaching processes related with soil rinsing which is part of the mining operations combined with intense rainfall. Our findings suggest that heavy metal concentrations in mining spoils should not be considered to constrain forest restoration efforts or the development of similar land uses as in comparable non-impacted high forest soils.

Mercury transport and fate in municipal solid waste landfills and its implications

Mercury (Hg) release and migration from municipal solid waste landfills has been an important issue to nearby ecosystems and human health. To completely understand the Hg biogeochemical cycle in landfills, this review presents the Hg emission processes via different pathways, related controlling mechanisms, and critical Hg transport and transformation processes involving the diffusion and advection of Hg, Hg volatilization, Hg adsorption and desorption, Hg redox reactions, and Hg methylation and demethylation. These critical physical, chemical, and biological processes result in the phase transfer of Hg and the distribution of different Hg species in landfill gas (LFG), leachates, and cover soils. In addition, key factors (e.g., LFG, meteorological conditions, cover soils, and vegetation) affecting Hg emission processes and their impacts are discussed here. This work provides a comprehensive picture of Hg behavior in landfills, and has positive implications for the development of a process-based model and the control of Hg emissions from landfills.

EFFECT OF WI-FI RADIATIONS ON AMALGAM RESTORATIONS IN CLASS V CAVITIES USING ICP-OES-AN IN VITRO STUDY

Context: This study has been conducted to study the effect of wifi radiations on amalgam restorations. Aims: To evaluate the release of mercury from class V cavities in presence of Wi-Fi radiations. Methods

Rethinking the Minamata Tragedy: What Mercury Species Was Really Responsible?

Industrial release of mercury into the local Minamata environment with consequent poisoning of local communities through contaminated fish and shellfish consumption is considered the classic case of environmental mercury poisoning. However, the mercury species in the factory effluent has proved controversial, originally suggested as inorganic, and more recently as methylmercury species. We used newly available methods to re-examine the cerebellum of historic Cat 717, which was fed factory effluent mixed with food to confirm the source. Synchrotron high-energy-resolution fluorescence detection-X-ray absorption spectroscopy revealed sulfur-bound organometallic mercury with a minor β-HgS phase. Density functional theory indicated energetic preference for α-mercuri-acetaldehyde as a waste product of aldehyde production. The consequences of this alternative species in the "classic" mercury poisoning should be re-evaluated.

Release characteristics of mercury in fly ashes collected from coal-fired CFB power units during thermal treatment

In order to investigate release characteristics of mercury in fly ashes collected from a coal-fired CFB power unit, the effect of temperature and time on mercury release characteristics of fly ash samples as well as release rules of mercury in fly ash samples were analyzed through the heat treatment experiments and temperature-programmed pyrolysis experiments. Moreover, the mechanism of mercury adsorption was examined based on the fitting results of first order kinetic model, Elovich kinetic model, Freundlich kinetic model and parabolic diffusion kinetic model. The results of heat treatment experiments showed that mercury release rate of the CFB fly ash was closely related to the heating temperature and time. The release rate of mercury in the CFB fly ash was lower than 0.2 at temperature below 200 ℃, while the release rate of mercury in the CFB fly ash was no less than 0.935 at the temperature over 300 ℃. The results of temperature-programmed pyrolysis experiments suggested that Mercury species present in the fly ash include HgCl2, Hg2Cl2, HgO, HgSO4, HgS (black) and HgS (red). HgS (black) and HgS (red) were the main mercury species present in the fly ash. The fitting results of kinetic equation showed that Elovich kinetic model was more applicable to reflect the Hg release from the fly ash, while the correlation coefficient R2 between the experimental and calculated data was greater than 0.95. It is indicated that this process controlled by multiple reaction mechanisms, and the activation energy changes greatly.

Assessment of territorial impact of industrial mercury pollution and proposal for its solution

The mercury electrolysis plant in Usolye Sibirskoye, which was decommissioned in 1998, is a source of mercury pollution, since measures to prevent mercury pollution of the environment were not implemented after its closure. On the territory of the plant, mercury remained in building structures, in sludge, in soils, in loose sediments. All of them are deposited sources of metallic mercury, from where it continues to spread in the air, soils and groundwater. In order to choose the best method to eliminate the source of mercury pollution, it is necessary to conduct an assessment of the impact on all elements of the environment and to identify the places with the highest mercury contamination. In addition, to propose environmental protection measures those are aimed at eliminating the main sources of metallic mercury release to the environment from the decommissioned mercury electrolysis plant. During the environmental impact assessment of the investigated object, the following tasks were performed: an assessment of the existing environmental situation and the state of the natural environment was carried out; alternative scenarios for achieving the planned activity were considered, with a justification for choosing the best one.