Air Hg Research Articles

One-year mortality and readmission risks following hospitalization for acute exacerbation of chronic obstructive pulmonary disease based on the types of acute respiratory failure: An observational study.

Few studies have examined the risk factors associated with the type of acute respiratory failure (ARF) in patients with acute exacerbation of chronic obstructive pulmonary disease (COPD). This study evaluated the clinical characteristics and prognosis of patients hospitalized for acute exacerbation of COPD based on the type of ARF. The medical charts of hospitalized patients with acute exacerbation of COPD between 2016 and 2021 were retrospectively reviewed. We classified ARF into 2 types: type 1 ARF with PaO2 < 60 mm Hg in room air or a ratio of arterial partial pressure to fractional inspired oxygen < 300, and type 2 ARF with PaCO2 > 45 mm Hg and arterial pH < 7.35. A total of 435 patients were enrolled in study, including 170 participants without ARF, 165 with type 1 ARF, and 100 with type 2 ARF. Compared with the non-ARF group, the frequency of high-flow nasal cannula, noninvasive ventilation, intensive care unit admissions, and in-hospital deaths was higher in the ARF group compared with the non-ARF group. The ARF group had higher 1-year mortality group (hazard ratio [HR], 2.809; 95% confidence interval [CI], 1.099-7.180; P = .031) and readmission within 1-year rates (HR, 1.561; 95% CI, 1.061-2.295; P = .024) than the non-ARF group. The type 1 ARF group had a higher risk of 1-year mortality (HR, 3.022; 95% CI, 1.041-8.774; P = .042) and hospital readmission within 1-year (HR, 2.053; 95% CI, 1.230-3.428; P = .006) compared with the non-ARF group. There was no difference in mortality and readmission rates between the type 1 and type 2 ARF groups. In conclusion, patients with type 1 ARF rather than type 2 ARF had higher mortality and readmission rates than those without ARF. The prognoses of patients with type 1 and type 2 ARF were similar.

Multimedia fate simulation of mercury in a coastal urban area based on the fugacity/aquivalence method

Due to intensive industrial production and living activities, urban areas are the main anthropogenic mercury (Hg) emission sources. After entering the environment through exhaust gases, wastewater or waste residues, Hg can migrate and transform among different environmental compartments in various species, such as elemental mercury (Hg0), divalent mercury (Hg2+) and methylmercury (MeHg). Studies have yet to report on the multimedia behaviors of Hg in urban areas due to the complexity of the processes involved. In this study, the atmospheric Hg emission in Dalian, a coastal city in Northeast China, was estimated by an anthropogenic emission inventory, and a Level III multimedia model was constructed based on the fugacity/aquivalence method to simulate the fate of Hg in air, water, soil, sediment, vegetation and film. The total annual atmospheric emission was 9.91 t, of which coal combustion and non-coal sources accounted for 70.1 % and 29.9 %, respectively. Atmospheric emission and advection were dominated by Hg0, and aquatic emission and advection were dominated by Hg2+. The migration of air–vegetation, vegetation–soil and soil–air were three important pathways of Hg in urban areas. The model was validated by collecting local soil and vegetation samples and regional air, seawater and sediment monitoring data. The scenario simulation indicated that the local load would decrease to different extents with a 21.0 % reduction in atmospheric Hg emission by implementing the “coal-to-gas” measures. Our developed model can characterize the fate of Hg in coastal urban areas and provide a reference for control strategies.

Multi-layered physical factors govern mercury release from soil: Implications for predicting the environmental fate of mercury

Despite the recognised risks of human exposure to mercury (Hg), the drivers of gaseous elemental mercury (GEM) emissions from the soil remain understudied. In this study, we aimed to identify the environmental parameters that affect the GEM flux from soil and derive the correlations between environmental parameters and GEM flux. Principal component analysis (PCA), factor analysis (FA), and structural equation modelling (SEM) were performed on samples from forest and non-forest sites. The associated results revealed the impact of each environmental parameter on GEM flux, either due to the interaction between the parameters or as a coherent set of parameters. An introductory correlation matrix examining the relationship between two components showed a negative correlation between GEM flux and atmospheric pressure at the two sites, as well as strong correlations between atmospheric pressure and soil temperature. In cases of non-forest open sites with no trees, the PCA and FA results were consistent, indicating that atmospheric pressure, solar irradiance, and soil moisture—defined as primary causality—are largely independent drivers of GEM flux. In contrast, the PCA and FA results for the forest areas with high humidity, tree coverage, and shade were inconsistent, confirming the hypothesis that primary causality affects GEM flux rather than consequent parameters driven by primary causality, such as air and soil temperature and atmospheric humidity. The SEM results provided further evidence for primary and consequent causality as crucial drivers of the GEM flux. This study demonstrates the importance of key primary parameters, such as atmospheric pressure, solar irradiance, and soil moisture content, that can be used to predict mercury release from soils, as well as the importance of consequent parameters, such as air and soil temperature and atmospheric humidity. Monitoring the magnitude of these environmental parameters alone may facilitate the estimation of mercury release from soils and be useful for detailed modelling of soil–air Hg exchange.

Study of heterogeneous chemistry and photochemistry of single sea-spray aerosols containing Hg(II) in air using optical trapping- Raman spectroscopy

Sea-spray aerosols (SSAs) contribute to atmospheric loading, bringing toxic compounds like mercury (Hg) to the atmosphere, affecting the climate and human health. Despite their importance, the investigation into surface modification,...

ВЛИЯНИЕ 21-СУТОЧНОЙ «СУХОЙ» ИММЕРСИИ НА ВЕНТИЛЯЦИОННУЮ РЕАКЦИЮ СИСТЕМЫ ДЫХАНИЯ НА НАРАСТАЮЩУЮ ГИПЕРКАПНИЮ

Effects of 21-d dry immersion (DI) on ventilation response to increasing hypercapnia were studied using the Starr "calm down" breathing. Ventilation response to СО2 (SVСО2) and changes in the respiration capacity due to growing hypercapnia (SVtCO2) were measured before, during and on completion of 21-d DI. Measurements in the course of DI included residual pulmonary volume (RPV), functional residual capacity (FRC) and CO transfer-coefficient of the lung (KCO). SVСО2 and SVtCO2 were determined within the CO2 partial pressure range of 45 - 60 mm Hg in the end-exhaled air (PETCO2). Since the subjects breathed an oxygen gas mixture and the hypoxic response could not develop, SVСО2 was determined by PETCO2 only. On DI days 13 and 19, group-average SVtCO2 was significantly (р&lt; 0.05) higher than the baseline value by 0.023 ± 0.019 and 0.018 ± 0.016 l/mmHg, respectively. On DI day 13, SVtCO2 was significantly (р&lt; 0.05) higher by 0.020 ± 0.023l/mmHg when compared to DI day 8. Throughout the DI study, the CO2-related apneic threshold tended to rise; on DI day 13, the threshold was significantly higher (Р&lt; 0.05) when compared to the value on DI day 8 (by 3.09 ± 4.07 mmHg). There was also a significant increase (Р&lt; 0.05) of the breathing capacity at the apneic threshold on DI day 13 when compared to the baseline value (by 6.47 ± 7.09 mmHg) and on day 8 (by 7.27 ± 9.15 mmHg). TLP decreased significantly (Р&lt; 0.05) on DI day 13 when compared to day 8 (by 0.14 ± 0.13 l).

Fractionation of mercury stable isotopes in lichens

Bio-monitoring of mercury (Hg) in air using transplanted and in-situ lichens was conducted at three locations in Slovenia: (I) the town of Idrija in the area of the former Hg mine, where Hg contamination is well known; (II) Anhovo, a settlement with a cement production plant, which is a source of Hg contamination, and (III) Pokljuka, a part of a national park. Lichens from Pokljuka were transplanted to different sites and sampled four times—once per season, from January 2020 to February 2021. Lichens were set on tree branches, fences, and under cover, allowing them to be exposed to different environmental conditions (e.g., light and rain). The in-situ lichens were sampled at the beginning and the end of the sampling period. The highest concentrations were in the Idrija area, which was consistent with previous research. Significant mass-dependent fractionation has been observed in transplanted lichens during summer period. The δ202Hg changed from −3.0‰ in winter to −1.0‰ in summer and dropped again to the same value in winter the following year. This trend was observed in all samples, except those from the most polluted Idrija sampling site, which was in the vicinity of the former Hg ore-smelting plant. This was likely due to large amounts of Hg originating from polluted soil close to the former smelting plant with a distinct isotopic fingerprint in this local area. The Δ199Hg in transplanted lichens ranged from −0.5‰ to −0.1‰ and showed no seasonal trends. These findings imply that seasonality, particularly in summer months, may affect the isotopic fractionation of Hg and should be considered in the sampling design and data interpretation. This trend was thus described in lichens for the first time. The mechanism behind such change is not yet fully understood.

Investigation of the biochemical controls on mercury uptake and mobility in trees

Atmospheric elemental mercury (Hg(0)) enters plant stomata, becomes oxidized, and is then transferred to annual growth rings providing an archive of air Hg(0) concentrations. To better understand the processes of Hg accumulation and translocation, the foliage of quaking aspen and Austrian pine were exposed to Hg(0), and methylmercury (MeHg) or Me198Hg via roots, in controlled exposures during the summer. Isotopic measurements demonstrated, in a laboratory setting, that the natural mass-dependent fractionation observed was the same as that measured in field studies, with the lighter isotopes being preferentially taken up by the leaves. Hg was measured in plant tissues across seasons. Aspen trees moved Hg into new growth immediately after exposure, resorbed Hg in the fall, and then distributed Hg to new growth tissues in the spring. Austrian pine did not reallocate Hg. Mercury measured in aspen leaf fractions of trees exposed to Hg(0) demonstrated that 85 % of Hg was in the cell wall. It was also found that redox-active molecules, such as H2O2, could potentiate the release of cell wall-bound Hg from aspen leaves, providing a potential mechanism for remobilization. Regardless of the mechanism, the ability of aspen to reallocate Hg to new tissues indicates that Hg distribution in tree rings from aspen do not provide a reliable record of yearly changes in atmospheric Hg(0).

Increased allergic and asthmatic risks in children residing in industrial areas by surveying the pre-inflammatory (IgE, IL-4 and IL-13) biomarkers.

Toxic metal(loid)s can lead to high damages on human. This work was conducted to investigate the levels of metal(loid)s in PM2.5 and a total of 123 male children's (aged 6-9years) blood chosen from different areas in Ahvaz and their association with the pre-inflammatory (Immunoglobulin E and cytokines: IgE, IL-4 and IL-13) responses in serum cells. Six metal(loid)s (arsenic, cadmium, chromium, mercury, nickel and lead) in three regions including industrial (Padad), vehicle traffic (Golestan) and reference (Kianpars) areas were studied. Results showed the concentrations of As, Cr, Cd, Ni and Hg in the ambient air of industrial area (Padad) (P < 0.001), and Pb in vehicle traffic area (Golestan) were higher (p < 0.001). Moreover, the mean levels of IgE (mean = 146.44pg/200landa, P < 0.003), IL-4 (mean = 548.23pg/200landa, P < 0.001) and IL-13 (mean = 53.21pg/200landa, P < 0.001) in Padad were higher than Golestan and Kianpars. Our results suggest that living in industrial areas leads to accelerated synthesis of IgE, IL-4 and IL-13 in blood. The spatial distribution of children's serum IgE, IL-4 and IL-13 concentrations showed an abnormal increase of 240 to 400pg/200landa for IgE, 950 to 1400pg/200landa for IL-4 and 90 to 128pg/200landa for IL-13. Our results indicate children in the industrial area are prone to asthma, allergy, miRNA mutation, and other chronic diseases.

Mercury pollution in Peru: geographic distribution, health hazards, and sustainable removal technologies.

Peru is one of the great gold producers worldwide. However, a significant portion of the gold produced in Peru derives from artisanal small-scale gold mining (ASGM) in the Andes and Amazon. In ASGM, gold amalgamation with mercury (Hg) is a critical procedure to refine gold through the formation of Au-Hg alloys. Due to the rudimentary and improvised techniques conducted by small-scale and informal miners, Hg contamination has become of great concern and is strictly associated with ASGM. Multiple studies have evidenced notably high concentrations of Hg in consumable fish species, rivers, sediments, and air in locations where ASGM is one of the main sources of income to local communities and is carried out aggressively. In the present review, we have conducted a systematic search for national and international literature reporting the concentration and distribution of Hg pollution across environmental compartments, biota, and human samples in Peru. The results and data retrieved from the articles were quantitatively and qualitatively analyzed, and the distribution of Hg across environmental compartments was visualized through a geographic information system. Additionally, we reviewed the use of adsorption techniques as alternatives to treat Hg0 vapor from the gold shop and smelter flues, one of the main sources of hazardous levels of Hg exposure.

Arctic atmospheric mercury: Sources and changes

Global anthropogenic and legacy mercury (Hg) emissions are the main sources of Arctic Hg contamination, primarily transported there via the atmosphere. This review summarizes the state of knowledge of the global anthropogenic sources of Hg emissions, and examines recent changes and source attribution of Hg transport and deposition to the Arctic using models. Estimated global anthropogenic Hg emissions to the atmosphere for 2015 were ~2220 Mg, ~20% higher than 2010. Global anthropogenic, legacy and geogenic Hg emissions were, respectively, responsible for 32%, 64% (wildfires: 6–10%) and 4% of the annual Arctic Hg deposition. Relative contributions to Arctic deposition of anthropogenic origin was dominated by sources in East Asia (32%), Commonwealth of Independent States (12%), and Africa (12%). Model results exhibit significant spatiotemporal variations in Arctic anthropogenic Hg deposition fluxes, driven by regional differences in Hg air transport routes, surface and precipitation uptake rates, and inter-seasonal differences in atmospheric circulation and deposition pathways. Model simulations reveal that changes in meteorology are having a profound impact on contemporary atmospheric Hg in the Arctic. Reversal of North Atlantic Oscillation phase from strongly negative in 2010 to positive in 2015, associated with lower temperature and more sea ice in the Canadian Arctic, Greenland and surrounding ocean, resulted in enhanced production of bromine species and Hg(0) oxidation and lower evasion of Hg(0) from ocean waters in 2015. This led to increased Hg(II) (and its deposition) and reduced Hg(0) air concentrations in these regions in line with High Arctic observations. However, combined changes in meteorology and anthropogenic emissions led to overall elevated modeled Arctic air Hg(0) levels in 2015 compared to 2010 contrary to observed declines at most monitoring sites, likely due to uncertainties in anthropogenic emission speciation, wildfire emissions and model representations of air-surface Hg fluxes.

Determination of Mercury (Hg) and Lead (Pb) in Sedimen of Batanghari River in Dharmasraya Regency

Batanghari River is a river that crosses the Province of West Sumatra and Jambi Province, which flows through the Dharmasraya Regency area. Along this river, many illegal gold mines are found, which use mercury (Hg) as a gold-binding medium, and fuel oil containing lead (Pb) as fuel for machinery used in mining operations. This mining activity is the cause of the presence of Hg and Pb in the mining environment which is passed by the Batanghari river. The source of Pb is also from tailings, which is the remaining metal ore processing that does not meet the requirements to be taken at the time of mining. the presence of Hg and Pb metals in the aquatic environment will have an impact on the environment and interfere with the health of miners and the surrounding community, because Hg and Pb are heavy metals that are toxic. Research has been carried out on the Batanghari river sediments in January and April 2019 using the Atomic Absorption Spectrophotometer (FAAS) method to measure Pb and the Cold Vapor Atomic Absorption Spectrophotometer (CV AAS) method for Hg metal. The results showed that each metal Hg and Pb, in mg metal per Kg sediment, in the range of 0.08 mg/kg – 10.21 mg/kg, and 1.81 mg/kg – 23.10 mg/kg. Based on these data, it can be said that in January and April 2019 the metal content of Hg and Pb in the Batanghari river air was above the river water quality standard according to the Government Regulation of the Republic of Indonesia, namely 0.001-0.002 mg/L for Hg and 0.03 mg/L for Pb

Reconstructing atmospheric Hg levels near the oldest chemical factory in central Europe using a tree ring archive

The Chemical Factory in Marktredwitz (CFM) is known as the oldest chemical factory in Germany (1778–1985), and from the beginning of the 20th century focused primarily on the production of mercury (Hg) compounds. Due to extensive pollution, together with employee health issues, the CFM was shut in 1985 by a government order and remediation works proceeded from 1986 to 1993. In this study, tree ring archives of European Larch (Larix decidua Mill.) were used to reconstruct changes of air Hg levels near the CFM. Mercury concentrations in larch boles decreased from 80.6 μg kg−1 at a distance of 0.34 km–3.4 μg kg−1 at a distance of 16 km. The temporal trend of atmospheric Hg emissions from the CFM reconstructed from the tree ring archives showed two main peaks. The first was in the 1920s, with a maximum tree ring Hg concentration 249.1 ± 43.9 μg kg−1 coinciding with when the factory had a worldwide monopoly on the production of Hg-based seed dressing fungicide. The second peak in the 1970s, with a maximum tree ring Hg concentration of 116.4 ± 6.3 μg kg−1, was associated with a peak in the general usage and production of Hg chemicals and goods. We used the tree ring record to reconstruct past atmospheric Hg levels using a simple model of Hg distribution between the larch tree rings and atmosphere. The precision of the tree ring model was checked against the results of air Hg measurements during the CFM remediation 30 years ago. According to the tree ring archives, the highest air Hg concentrations in the 1920s in Marktredwitz were over 70 ng m−3. Current air Hg levels of 1.18 ng m−3, assessed in the city of Marktredwitz, indicate the lowest air Hg in the past 150 years, underscoring the effective remediation of the CFM premises 30 years ago.

Mercury pollution in China: implications on the implementation of the Minamata Convention.

Mercury (Hg) is a toxic metal released into the environment through human activities and natural processes. Human activities have profoundly increased the amount of Hg in the atmosphere and altered its global cycling since the Industrial Revolution. Gaseous elemental Hg is the predominant form of Hg in the atmosphere, which can undergo long-range transport and atmospheric deposition into the aquatic systems. Hg deposition elevates the methylmercury (MeHg) level in fish through bioaccumulation and biomagnification, which poses a serious human health risk. Acute poisoning of MeHg can result in Minamata disease, while low-level long-term exposure in pregnant women can reduce the intelligence quotient of infants. After five sessions of intergovernmental negotiation, the Minamata Convention on mercury entered into force in August 2017 to protect human health and the environment from Hg pollution. Currently China contributes the largest quantity of Hg production, consumption, and emission globally. However, the status of Hg pollution in the environment in China and its associated health risk remains relatively unknown, which hinders the development of implementation plans of the Minamata Convention. In this paper, we provide a comprehensive review on the atmospheric release of Hg, distribution of air Hg concentration, human exposure to MeHg and health impacts caused by Hg pollution in China. Ongoing improvement of air pollution control measures is expected to further decrease anthropogenic Hg emissions in China. Air Hg concentrations in China are higher than the background values in the Northern Hemisphere, with spatial distribution largely influenced by anthropogenic emissions. Long-term observations of GEM in China show a decline in recent years. The net Hg transport outflow from China in 2013 is estimated to be 511 t year-1, and ∼60% of such outflow is caused by natural surface Hg emissions. Hg concentrations in fish and rice in China are relatively low and therefore the associated risks of human Hg exposure are low. Future research needs and recommendations for the implementation of the Minamata Convention are also discussed in this paper.

Particle size distributions and seasonal concentrations study of atmospheric pollutants (particulates, Hg(p)) at an agricultural site in Taiwan

The concentrations of ambient air particulates of various sizes (PM1, PM2.5, PM6.25, PM10 and PM18) were measured using a MOUDI sampler at an agricultural sampling site in central Taiwan from January to September, 2020. The concentrations of particulate-bound mercury Hg(p) that were attached to particulates of various sizes (PM1, PM2.5, PM6.25, PM10 and PM18)) were analyzed using a Direct Mercury Analyzer (DMA-80). The results revealed that the mean particulate and Hg(p) concentrations associated with PM18, PM10, PM6.25, PM2.5 and the back filter were all highest in autumn and winter. The mean mass median diameter (m.m.d.) value for ambient air particulates was highest in the summer and lowest for Hg(p). The mean m.m.d. value for ambient air Hg(p) was highest in the winter and lowest for ambient air particulates. The northeast monsoon prevails in the winter season of Taiwan. Thus, The sources of particulates and Hg(p) pollutants might came from the northeast side of Taiwan - especially in spring and winter seasons. Thus, ambient air particulate concentrations are higher in the winter than in the spring. However, ambient air particulate-bound mercury Hg(p) tended to be associated more with coarse particulates than with other particulates. Finally, Hg(p) concentrations in Taiwan have increased over the last 15 years. Reducing atmospheric Hg(p) concentrations has become an important environmental goal in all countries - especially those in Asia.

Ambient air particulates and Hg(p) concentrations and dry depositions estimations, distributions for various particles sizes ranges

Ambient air TSP concentrations, dry deposition fluxes and particulate-bound mercury (Hg(p)) concentrations were measured and analyzed at a complex (traffic, residential and commercial) site. Zhang and He’s model[ 1 ] was used to predict the dry deposition fluxes of ambient air particulates and Hg(p) at this complex site. The results revealed that October had the highest mean particulate concentration and lowest Hp(p) concentration and dry deposition flux. The mean calculated dry deposition fluxes of PM2.5 and PM2.5-10 accounted for 1%–2% and 0.06%–5% of the average total calculated dry deposition particle flux, respectively. The average calculated particle dry depositions flux of PM10+, accounted for 93%–99% of the average total calculated dry depositions particle flux. Finally, the model of Zhang and He underestimated the ambient air dry depositions fluxes of both particulates and Hg(p) for all particles sizes (PM2.5, PM2.5-10, PM10 +) at the mixed site in this study. Better results concerning the dry deposition fluxes of pollutants were obtained as the particles size increased.

Air Concentrations of Gaseous Elemental Mercury and Vegetation–Air Fluxes within Saltmarshes of the Tagus Estuary, Portugal

In situ air concentrations of gaseous elemental mercury (Hg(0)) and vegetation–atmosphere fluxes were quantified in both high (Cala Norte, CN) and low-to-moderate (Alcochete, ALC) Hg-contaminated saltmarsh areas of the Tagus estuary colonized by plant species Halimione portulacoides (Hp) and Sarcocornia fruticosa (Sf). Atmospheric Hg(0) ranged between 1.08–18.15 ng m−3 in CN and 1.18–3.53 ng m−3 in ALC. In CN, most of the high Hg(0) levels occurred during nighttime, while the opposite was observed at ALC, suggesting that photoreduction was not driving the air Hg(0) concentrations at the contaminated site. Vegetation–air Hg(0) fluxes were low in ALC and ranged from −0.76 to 1.52 ng m−2 (leaf area) h−1 for Hp and from −0.40 to 1.28 ng m−2 (leaf area) h−1 for Sf. In CN, higher Hg fluxes were observed for both plants, ranging from −9.90 to 15.45 ng m−2 (leaf area) h−1 for Hp and from −8.93 to 12.58 ng m−2 (leaf area) h−1 for Sf. Mercury flux results at CN were considered less reliable due to large and fast variations in the ambient air concentrations of Hg(0), which may have been influenced by emissions from the nearby chlor-alkali plant, or historical contamination. Improved experimental setup, the influence of high local Hg concentrations and the seasonal activity of the plants must be considered when assessing vegetation–air Hg(0) fluxes in Hg-contaminated areas.

Ultrafast removal of ppb levels of Hg(II) and volatile Hg(0) using post modified metal organic framework

A novel MOF based adsorbent was prepared by functionalization of MIL 88A with mercapto ethanol to yield MIL88A-SH and evaluated for the removal of Hg(II) in water and Hg(0) in air. The prepared MOFs were characterized by field emission scanning electron microscope (FESEM), Transmission electron microscopy (TEM), Brunauer- Emmett-Teller (BET), Fourier transform infrared spectroscopy (FTIR), and zeta X-ray photoelectron microscopy (XPS). The reaction rate was found to be very fast and within 15 min 95.5% Hg(II) was removed. The kinetics data followed pseudo second order model with rate constant values at 1.19 and 2.38 g/μg/min for MIl88A and MIL88A-SH respectively. A very high adsorption capacity in the order 1111.1 mg/g of Hg(II) was found using MIL88A-SH as adsorbent. The uptake was found to be constant in a wide range of pH from 5 to 9. Furthermore, in the presence other interfering metal ions, viz., Cu(II), As(V), Cd(II), Cr(VI), Pb(II), Zn(II), MIL88A-SH demonstrated an excellent adsorption for Hg(II). Around 45.6 mg/g of Hg(0) was found to be adsorbed by MIL88A-SH. XPS, FTIR and XRD studies suggested insitu oxidation Hg(0) to Hg(II) and complexation of Hg(II) with thiol groups during adsorption. Applicability on removal of Hg(II) at ppb levels from drinking water, fast kinetics, wide pH range, a very high sorption capacity, Hg(0) removal, selectivity and recyclability makes MIL88A-SH an efficient adsorbent to tackle mercury contamination.

Influences of high-level atmospheric gaseous elemental mercury on methylmercury accumulation in maize (Zea mays L.)

Maize (Zea mays L.) leaves play an important role in stomatal uptake and surface adsorption of atmospheric mercury (Hg). However, the influence of atmospheric gaseous elemental mercury (GEM) on methylmercury (MeHg) accumulation in maize plants is poorly understood. In this study, we conducted a field open-top chambers (OTCs) experiment and a soil Hg-enriched experiment to investigate the response of MeHg accumulation in maize tissues to different GEM levels in the air. Maize upper leaves had a higher average MeHg concentration (0.21 ± 0.08 ng g−1) than bottom leaves (0.15 ± 0.05 ng g−1) in the OTCs experiment, which was inconsistent with that in the soil Hg-enriched experiment (maize upper leaves: 0.41 ± 0.07 ng g−1, maize bottom leaves: 0.60 ± 0.05 ng g−1). Additionally, significantly positive correlations were found between MeHg concentrations in maize leaves and air Hg levels, suggesting that elevated air Hg levels enhanced MeHg accumulation in maize leaves, which was possibly attributed to methylation of Hg on leaf surfaces. Mature maize grains from the OTCs experiment had low MeHg concentrations (0.12–0.23 ng g−1), suggesting a low accumulation capability of MeHg by maize grains. Approximately 93–96% of MeHg and 51–73% of total Hg in maize grains were lost from the grain-filling stage to the grain-ripening stage at all GEM level treatments, implying that self-detoxification in maize grains occurred. MeHg concentrations in maize roots showed a significant linear relationship (R2 = 0.98, p < 0.01) with soil Hg levels, confirming that MeHg in maize roots is primarily from soil. This study provides a new finding that elevated air GEM levels could enhance MeHg accumulation in maize leaves, and self-detoxification may occur in maize grains. Further studies are needed to clarify these mechanisms of Hg methylation on maize leaf surfaces and self-detoxification of Hg by maize grains.

Microfluidic paper-based analytical device using gold nanoparticles modified with N,N′-bis(2-hydroxyethyl)dithiooxamide for detection of Hg(ii) in air, fish and water samples

A new method for visual detection of mercury by color change is developed that can detect Hg2+ by the naked eye or a digital camera.

Particulates and particulates-bound mercury (Hg(p)) sizes (PM18, PM10, PM2.5, PM1, PM

The objectives of this study were to measure ambient air particles concentrations of different particulates sizes ranges (PM18, PM10, PM2.5, PM1, PM<1) at a complex (traffic, residential and commercial) site. Besides, particulates-bound mercury (Hg(p)) concentrations for various particulates sizes (PM18, PM10, PM2.5, PM1, PM<1) at mixed site were also studied. Finally, ambient air particulates and Hg(p) size distributions were also described at this complex sampling site. The results showed that the average PM18, PM10, PM2.5, PM1, PM<1 concentrations were 48.83, 41.78, 35.41, 19.89, and 11.86μg/m3, respectively. And the average ambient air particulates-bound mercury (Hg(p)) which attached on PM18, PM10, PM2.5, PM1, PM<1 particles concentrations were 0.0838, 0.0867, 0.0790, 0.0546, and 0.0373ng/m3, respectively, in the summer season. In addition, the average ambient air Hg(p) which attached on PM18, PM10, PM2.5, PM1, PM<1 particles concentrations were 0.0175, 0.0144, 0.0120, 0.0092, and 0.0057ng/m3, respectively, in the autumn season. Finally, the average ambient air Hg(p) which attached on PM18, PM10, PM2.5, PM1, PM<1 particles concentrations were 0.0070, 0.0053, 0.0038, 0.0026, and 0.0014ng/m3, respectively, in the winter season. And July has the average highest PM18 and PM10 concentrations. As for PM2.5, PM1 and PM<1 particulates, the average highest particulates concentrations all occurred in November. In addition, the highest average Hg(p) in PM18, PM10, PM2.5, PM1, and PM<1 concentrations all occurred in July. Moreover, the average particles and particulates-bound mercury m.m.d. values were ranged from 1.0 to 1.8 and 0.7 to 2.0μm from July to December of 2018, respectively, at this mixed sampling site. As for monthly ambient air particles sizes distributions, the results further showed that the main peaks for July, September, and December all occurred in the sizes of 10-18μm. The main peaks for October and November all occurred in the sizes of 2.5-10μm. As for monthly Hg(p) sizes distributions, the results further showed that the main peaks for July occurred in the size of 0.3-1μm. The main peak for September occurred in the size of 1-2.5μm. The main peaks for October to December all occurred in the size of 10-18μm. The above finding further concluded that the particulates-bound mercury (Hg(p)) was tended to be associated with the large particles sizes mode during the winter season. Finally, this study further shows that the Taichung Thermal Power Plant was responsible for the main emission source of Hg(p) especially in summer season of Central Taiwan.