Mercury Emissions Research Articles

Mercury in an Australian sclerophyll Eucalyptus forest and emissions from fuel reduction prescribed burning

Environmental context Understanding how mercury cycles through the environment is crucial for protecting ecosystems and human health. Our study is among the first to measure mercury concentrations in Eucalyptus forest soils and litter and estimate emissions from prescribed burns, addressing a significant gap in current knowledge. These new data enhance our understanding of mercury cycling in Australia and contribute to the global information on the biogeochemical cycle of mercury. Rationale Research on mercury in Australian soils and litter is sparse. This study aims to address this knowledge gap by investigating mercury pools in soil and litter in a eucalypt forest in Victoria, Australia. Methodology We analysed total mercury concentrations in O and A horizon soils, and twig, bark and leaf litter. Soil samples were collected from an area affected by a prescribed burn and unburned areas. Additionally, soil samples from the base of tree stems were taken in unburned areas. The organic matter content of all soil samples was also assessed. Results In unburned soils, mean mercury concentrations at the base of tree stems, in the O-horizon and A horizon were 143 ± 61, 112 ± 71 and 56 ± 30 ng g−1 respectively. In burned soils, mean mercury concentrations in the O and A horizons were 91 ± 63 and 46 ± 19 ng g−1 respectively. Mercury concentrations in leaf, bark and twig litter averaged 71 ± 11, 21 ± 13 and 8 ± 4 ng g−1 respectively. The emission factor was estimated as 0.247 g Hg ha−1. Discussion The studied sclerophyll forest represents a significant mercury reservoir. Burning did not significantly alter the mercury burden in soil; however, emissions of mercury from litter did occur. This finding underscores the need for more comprehensive research into mercury cycling in Australia and suggests that prescribed burning practices should account for potential mercury emissions.

Study on the Desorption Mechanism of Sulfur Dioxide–Modified Activated Carbon Based on Density Functional Theory

ABSTRACTActivated carbon injection technology is the primary method used to control the mercury emissions from coal‐fired power plants. The preparation of sulfur‐loaded carbon‐based adsorbents through SO2 modification of the surface of activated carbon (the primary component) provides an effective solution to enhancing the mercury removal performance of adsorbents. However, there remains a lack of clarity on the adsorption performance and mechanism of mercury on the newly formed active sites of the carbon surface after SO2 sulfur loading modification. In this study, four potential structures of SO2 loaded onto the surface of activated carbon were constructed. Quantum chemical calculation methods were applied to calculate the adsorption process of Hg in these four models, with those important characteristics identified such as bonding properties, adsorption energy, electrostatic potential, and molecular orbitals. As indicated by those results, the adsorption bonds of the SO2‐modified activated carbon were mainly C‐O‐S and C‐S‐C. After the carbon cluster model adsorbed SO2 molecules, the sulfur in SO2 exhibited a strong positive potential that facilitated the loss of electrons from Hg due to the potential difference. Consequently, HgO was firmly adsorbed onto the surface of the carbon cluster. As revealed by the molecular orbital calculations performed after Hg adsorption on the two carbon cluster models, SO2‐modified and elemental sulfur‐modified activated carbons, in the SOAC‐Arm‐1 configuration, there was a clear exchange orbital around the adsorbed Hg atom in the LUMO, with a small HOMO–LUMO energy gap of only 0.01713 eV. At this point, the free electrons on the molecule were prone to orbital transitions, promoting the occurrence of adsorption reactions. The SOAC‐Arm‐3 conformation exhibited the shortest C‐Hg bond length and had an adsorption energy of up to −70.42 kJ/mol, indicating a stronger chemical bonding ability and a higher likelihood of adsorption reactions. These results demonstrate the feasibility of sulfur‐loaded modified activated carbon to mitigate Hg pollution through SO2.

Novel mercury adsorption mechanism with bimetallic synergistic Se site: CuInSe2 for mercury fixation with wide temperature range from coal-fired flue gas

Mercury emissions from coal-fired power plants pose a significant threat to both the environment and human health. In this work, a novel CuInSe2 adsorbent with active selenium sites was synthesized for the removal of gaseous Hg0 during deep flue gas purification. This adsorbent serves as a bridge to establish the intrinsic connection between the new adsorption mechanism and mercury removal via bimetallic synergistic catalytic sites. By innovatively calculating the adsorption kinetics of the bimetallic selenide, along with XPS analysis and thermodynamic calculations, the reaction pathway of Hg0 on the surface of CuInSe2 and the proposed adsorption mechanism were validated. Additionally, the stable formation of HgSe on the lattice surface was confirmed. Characterization techniques such as SEM, TEM, and BET revealed the microscopic flower-like structure of CuInSe2 and confirmed the uniform distribution of active selenium sites. Experimental results demonstrate that CuInSe2 achieves nearly 100 % removal efficiency in the temperature range of 80–200 °C, and even after 6 hours of continuous operation, it maintains a removal rate of 96.49 %, showcasing excellent stability. Furthermore, due to its unique structural features, CuInSe2 exhibits strong resistance to interference from SO2 and NO, with an equilibrium adsorption capacity of 18.855 mg/g, surpassing most currently studied demercuration adsorbents. This makes CuInSe2 a highly promising material for mercury removal and provides an important reference for the development of selenium-rich site adsorbents.

Perspectives on using peat records to reconstruct past atmospheric Hg levels

Anthropogenic mercury (Hg) emissions to the atmosphere have increased the concentration of this potent neurotoxin in terrestrial and aquatic ecosystems. The magnitude of regional variation in atmospheric Hg pollution levels raises questions about the interactions between natural processes and human activities at local and regional scales that are shaping global atmospheric Hg cycling. Peatlands are potentially valuable and widespread records of past atmospheric Hg levels that could help address these questions. This perspective aims to improve the utility of peatlands as authentic Hg archives by summarizing the processes that could affect Hg cycling in peatlands. We identify the overlooked role of peat vegetation species and their primary productivity in Hg sequestration under climatic and anthropogenic activities. We provide recommendations to improve the reliability of using peat cores to reconstruct the atmospheric Hg levels from past decades to millennia. Better information from peatland archives on regional variation in atmospheric Hg levels will be of value for testing hypotheses about the processes controlling global Hg cycling. This information can also contribute to evaluating how well international efforts under the UNEP Minamata Convention are succeeding in reducing atmospheric Hg levels and deposition in different regions.

Influence of Finishing Process Parameters of HDF Boards on Selected Properties of Coatings in Modern UV Lines and Their Relation to Energy Consumption.

This study analyzes the influence of energy generated by emitters on the adhesive properties of varnish coatings in multilayer UV systems. The experimental material, in the form of a cell board finished with UV varnish products, was prepared on a prototype line under the conditions of Borne Furniture in Gorzów Wielkopolski. The roughness and wettability were measured using a OneAttension tensiometer integrated with a topographic module, taking into account the Wenzel coefficient. The adhesion of the examined systems was verified using the PositiTest AT-A automatic pull-off device. Energy consumption by the prototype production line was compared to the standard line, utilizing mercury emitters and mercury emitters with added gallium. Energy consumption was calculated for selected variants. The influence of the Wenzel coefficient on the wettability angle was observed. Significant differences between contact angles (CA and CAc) were noted for coatings formed with sealers (stages I and II). The largest discrepancies, reaching up to 30 degrees, were recorded at the lowest UVA and UVV doses of 26 mJ/cm2. In adhesion tests, values below 1 MPa were obtained. Insufficient energy doses in the curing process of UV systems led to delamination between the coatings. Five variants were selected where delamination within the substrate predominated (˃90% A) and were characterized by the lowest energy consumption in the processes. Topographic images helped identify the presence of various surface microstructures at different stages of the production cycle. The greatest energy savings, up to 50%, were achieved in stages III and IV of the technological process.

Examining Complexities of Artisanal and Small-Scale Gold Mining on Buru Island, Maluku Province, Indonesia

The Artisanal and Small-scale Gold Mining (ASGM) sector is presently one of the largest global sources of anthropogenic mercury emissions. The risk of mercury pollution from ASGM in Indonesia challenges other important industries including fisheries and tourism. Environmental degradation and risks to food safety and human health are major concerns that have been realised at local scales, including on Buru Island, Indonesia. Since the discovery of gold on Buru Island in 2011 the community has undergone dramatic changes. Some of these, such as rapid wealth accumulation, have been of benefit to people involved in the industry, however, they have been marred by negative social and economic consequences including rapid inflation, reduced rice production, and changes to the social fabric. We explore the Buru Island example through over 12 years of research interest and using empirical material through a socio-legal lens. Various legislative changes and government interventions have occurred since 2011 and there are complex interactions between industry players. Currently, the mining is low key with ore being transported to ‘back yard’ processing operations while a permitting system is anticipated. There is a legacy of land degradation and contamination as a result of the mining and ore processing. Alternatives to mercury are being considered but are challenged by uncertainty about product effectiveness, potential toxicity, and a lack of processing knowledge.

Projecting Future Mercury Emissions From Global Biofuel Combustion Under the Carbon Neutrality Target

AbstractBiomass plays a crucial role in the low‐carbon energy transition, with a projected contribution of 18.7% to the global energy supply by 2050. However, biofuel combustion has been a notable source of toxic mercury emissions, yet the future trends and distribution of the emissions remain inadequately understood. Here, we projected biofuel combustion under various Shared Socioeconomic Pathways (SSPs) using the Global Change Assessment Model and assessed associated mercury emissions in cooking, heating, and power generation over 2020–2050, aligning with the carbon neutrality target. Our analysis reveals that global biofuel mercury emissions are projected to be 9.90–18.40 tons by 2050, compared to the annual emissions of 13.89 tons in 2020. Notably, a substantial increase in emissions from power generation is expected, escalating from 0.57 tons in 2020 to 4.69–8.27 tons by 2050, with China and Southeast Asia emerging as primary contributors. Conversely, mercury emissions from cooking and heating are expected to decrease from 13.32 tons in 2020 to 4.40–11.53 tons by 2050, except in Africa under SSP2, where the emissions may increase from 5.91 to 6.69 tons. Our findings provide a scientific basis for policies aimed at achieving carbon neutrality targets while adhering to the Minamata Convention on Mercury.

Transmission centers of global embodied mercury emissions are moving from developed to developing regions

Mercury (Hg) can accumulate in the food chain, posing significant threats to human health and biodiversity. Existing studies have identified critical primary suppliers, producers, and final consumers driving Hg emissions in global supply chains. However, the hotspots in the intermediate transmission stages of global supply chains remain unknown. This study reveals critical transmission sectors and transactions of global embodied Hg emissions during 1995–2022. Results show that the critical transmission sectors and transactions of global embodied Hg emissions have been moving from developed (e.g., Japan and Russia) to developing (e.g., China and India) economies. Critical transmission sectors were primarily concentrated in the metal products, transportation, machinery and equipment manufacturing, and construction industries. Domestic transactions were the primary transmission pathways for embodied Hg emissions, with nearly half of these being intra-sectoral transactions. These findings can help policymakers develop transmission-bound Hg reduction policies and multi-level cooperation to support joint Hg emission reduction.

Mercury emission and fate characteristics in various combustion sources

In this study, we investigated the behavior and emission characteristics of Hg across diverse industrial combustion sources, such as coal-fired power plants, solid refuse fuel (SRF) power plants, medical waste incinerators, and industrial waste incinerators, as well as the development of emission factors, Among the facilities, the estimated Hg control efficiency was 86% for coal-fired power plants, 69% for SRF power plants, and over 95% for medical and industrial waste incinerators. The oxidation and regulation of elemental Hg (Hg0) are considered important factors in reducing Hg air emissions, with the flue gas HCl concentration being the primary factor affecting Hg oxidation. Particulate Hg was mainly controlled in the electrostatic precipitator (ESP) at the power plant, effectively capturing dust particles ranging from 10 to 100 μm. The emission factors estimated by measuring stack flue gas exhibited their highest values at SRF power plants, with an estimated average of 127±25 mg/ton, while the lowest values were observed for industrial waste incinerators, with an average of 2.5±0.3 mg/ton. This study is significant in that it provides a comparative analysis of various real industrial cases, and the Hg emission factors are expected to offer valuable data for estimating future national Hg air emissions.

Risk map of human intake of mercury through fish consumption in Latin America and the Caribbean

Mercury (Hg) is a persistent pollutant highly bioaccumulated in the aquatic environment through the food chain reaching high concentration levels in the tissues of predator fishes. Among the relevant sources of anthropogenic mercury emissions in Latin America and the Caribbean (LAC), mining is one of the most important along with soil erosion due to deforestation and agricultural activities where pesticides are intensively used. Several reports have demonstrated an association between a fish-based diet with elevated Hg levels in the blood and neurotoxic effects in humans. In this systematic review with quantitative analysis data from 92 articles were compiled, providing evidence of Hg concentration in fishes that are commonly consumed in LAC. An assessment was conducted using three indices for health risk: the Minamata Initial Assessment (MIA), the Target Hazard Quotient (THQ), and the Meals per Week (MPW) index. Of the 410 fish species studied, 5.4% had concentrations above 0.95 μg g−1 of wet weight (ww), which is the recommended limit for Total Hg (THg) ingestion through fish consumption according to the MIA index, regardless of the water habitat (i.e., marine or freshwater). Additionally, the Target Hazard Quotient (THQ) calculation indicated high-risk values (THQ ≥ 1) in 15 out of the 19 countries studied, and very high-risk values (THQ ≥ 10) were obtained from Hg concentrations measured in 5 fish species inhabiting watersheds in Trinidad and Tobago, Suriname and Peru. Finally, recommendations on fish consumption were made based on the MPW index. This study reveals the need for updated biomonitoring studies of Hg concentrations in fish to perform more accurate human health risk analyses.

Atmospheric Mercury Concentrations and Isotopic Compositions Impacted by Typical Anthropogenic Mercury Emissions Sources.

Coal-fired power plants (CFPPs) and cement plants (CPs) are important anthropogenic mercury (Hg) emission sources. Mercury speciation profiles in flue gas are different among these sources, leading to significant variations in local atmospheric Hg deposition. To quantify the impacts of Hg emissions from CFPPs and CPs on local-scale atmospheric Hg deposition, this study determined concentrations and isotopes of ambient gaseous elemental mercury (GEM), particulate-bound mercury (PBM), and precipitation total Hg (THg) at multiple locations with different distances away from a CFPP and a CP. Higher concentrations of GEM and precipitation THg in the CFPP area in summer were caused by higher Hg emission from the CFPP, resulting from higher electricity demand. Higher concentrations of GEM, PBM, and precipitation THg in the CP area in winter compared to those in summer were related to the higher output of cement. Atmospheric Hg concentration peaked near the CFPP and CP and decreased with distance from the plants. Elevated GEM concentration in the CFPP area was due to flue gas Hg0 emissions, and high PBM and precipitation Hg concentrations in the CP area were attributed to divalent Hg emissions. It was estimated that Hg emissions from the CFPP contributed 58.3 ± 20.9 and 52.3 ± 25.9% to local GEM and PBM, respectively, and those from the CP contributed 47.0 ± 16.7 and 60.0 ± 25.9% to local GEM and PBM, respectively. This study demonstrates that speciated Hg from anthropogenic emissions posed distinct impacts on the local atmospheric Hg cycle, indicating that Hg speciation profiles from these sources should be considered for evaluating the effectiveness of emission reduction policies. This study also highlights the Hg isotope as a useful tool for monitoring environmental Hg emissions.

Isotope-Based Characterization of Soil Elemental Mercury Emissions from Historical Mercury Mining Areas: Driving Pathways and Relative Contributions.

Photo-, microbial, and abiotic dark reduction of soil mercury (Hg) may all lead to elemental mercury (Hg(0)) emissions. Utilizing lab incubations, isotope signatures of Hg(0) emitted from mining soils were characterized to quantify the interplay and contributions of various Hg reduction pathways, which have been scarcely studied. At 15 °C, microbial reduced Hg(0) showed a negative mass-dependent fractionation (MDF) (δ202Hg = -0.30 ± 0.08‰, 1SD) and near-zero mass-independent fractionation (MIF) (Δ199Hg = 0.01 ± 0.04‰, 1SD), closely resembling dark reduced Hg(0) (δ202Hg = -0.18 ± 0.05‰, Δ199Hg = -0.01 ± 0.03‰, 1SD). In comparison, photoreduced Hg(0) exhibited significant MDF and MIF (δ202Hg = -0.55 ± 0.05‰, Δ199Hg = -0.20 ± 0.07‰, 1SD). In the dark, Hg isotopic signatures remained constant over the temperature range of 15-35 °C. Nonetheless, light exposure and temperature changes together altered Hg(0) MIF signatures significantly. Isotope mixing models along with Hg(0) emission flux data highlighted photo- and microbial reduction contributing 79-88 and 12-21%, respectively, of the total Hg(0) emissions from mining soils, with negligible abiotic dark reduction. Microorganisms are the key driver of soil Hg(0) emissions by first dissolving HgS and then promoting ionic Hg formation, followed by facilitating the photo- and microbial reduction of organically bound Hg. These insights deepen our understanding of the biogeochemical processes that influence Hg(0) releases from surface soils.

Pre-combustion mercury removal potential of rapid pyrolysis in high ash coal and mode of occurrence

Mercury is a widely known pollutant, and coal combustion is one of the largest sources of anthropogenic Hg emission. Mercury reduction technologies globally rely on flue gas treatment. However, pre-combustion techniques show immense potential. Mild pyrolysis of coal offers a promising approach for mitigating mercury emissions. This study investigated the mercury distribution and its mode of occurrence in six high ash coal samples from the Jagannath area of eastern India. The findings revealed that Hg content in coal samples ranged from 0.154-0.308 mg/kg. Majority of the mercury was bound to pyrites (60–90 %) and organic matter (5–15 %). Rapid pyrolysis at temperatures ranging from 200 to 700 °C demonstrated significant mercury removal efficiency (up to 95 %). In particular, at 400 °C with minimal loss in calorific value and mass. Though the high-temperature pyrolysis (600 °C) resulted in maximum mercury removal, but with a notable loss in calorific value and product yield. The Hg content in raw coal, initially ranging from 9 to 20 μg Hg/MJ, was reduced to 3 to 11 μg Hg/MJ in char produced at 400 °C. Further reduction was observed in char produced at 600 °C, where the Hg content decreased to between 2–3 μg Hg/MJ. This research emphasizes the effectiveness of mild pyrolysis in reducing mercury content of high ash coal, thereby facilitating the generation of cleaner energy.

Improving a continuous mercury analyzer with circulated carrier gas: Economic and operational advancements

Elevated mercury (Hg) emissions since industrialization have created worldwide elevated levels of Hg in environment, causing ecosystem and human health impacts. Addressing these concerns requires across-nation efforts and international cooperation. In cooperation with the United Nations Environment Programme (UNEP), through its implementation of the Minamata Convention (MC), several international and intranational projects have monitored Hg levels in the atmosphere, water, soil and biota for decades. Obviously, these global monitoring projects require substantial resources, such as government funding, human resources, and analytic instruments. Different types of Hg analyzers have been developed and used in these global monitoring projects, however, most of them require inert carrier gas (i.e. Ar, He) supply, especially if detection requires fluorescence spectroscopy. Frequent consumption and replenishment of carrier gas during normal operation incur substantial financial and human resource costs. Therefore, these instruments cannot operate autonomously for long periods of time and require a carrier gas cylinder exchange, a limitation especially in remote regions and on ocean research cruise campaigns where it is challenging to function autonomously for long duration, limiting data collection in these locations. To address this issue, we developed a novel prototype automated Hg analyzer with a new design using a circulated carrier gas system. This development decreases the carrier gas consumption and increases the Hg analyzer operation duration, saving up to 99% on carrier gas consumption compared to the widely used Tekran 2537 and NIC AM-6F atmospheric Hg analyzers instruments. By using the circulated carrier gas design, our Hg analyzer only consumes 1 L per week. Overall, this improvement not only saves carrier gas but also enhances the instrument's self-operating capability in remote areas and reduces the financial and human resource costs associated with frequent replacement of the carrier gas.

Mediterranean Marine Mammals: Possible Future Trends and Threats Due to Mercury Contamination and Interaction with Other Environmental Stressors.

Despite decreasing anthropogenic mercury (Hg) emissions in Europe and the banning and restriction of many persistent organic pollutants (POPs) under the Stockholm Convention, Mediterranean marine mammals still have one of the highest body burdens of persistent pollutants in the world. Moreover, the Mediterranean basin is one of the most sensitive to climate change, with likely changes in the biogeochemical cycle and bioavailability of Hg, primary productivity, and the length and composition of pelagic food webs. The availability of food resources for marine mammals is also affected by widespread overfishing and the increasing number of alien species colonizing the basin. After reporting the most recent findings on the biogeochemical cycle of Hg in the Mediterranean Sea and the physico-chemical and bio-ecological factors determining its exceptional bioaccumulation in odontocetes, this review discusses possible future changes in the bioavailability of the metal. Recent ocean-atmosphere-land models predict that in mid-latitude seas, water warming (which in the Mediterranean is 20% faster than the global average) is likely to decrease the solubility of Hg and favor the escape of the metal to the atmosphere. However, the basin has been affected for thousands of years by natural and anthropogenic inputs of metals and climate change with sea level rise (3.6 ± 0.3 mm year-1 in the last two decades), and the frequency of extreme weather events will likely remobilize a large amount of legacy Hg from soils, riverine, and coastal sediments. Moreover, possible changes in pelagic food webs and food availability could determine dietary shifts and lower growth rates in Mediterranean cetaceans, increasing their Hg body burden. Although, in adulthood, many marine mammals have evolved the ability to detoxify monomethylmercury (MMHg) and store the metal in the liver and other organs as insoluble HgSe crystals, in Mediterranean populations more exposed to the metal, this process can deplete the biological pool of Se, increasing their susceptibility to infectious diseases and autoimmune disorders. Mediterranean mammals are also among the most exposed in the world to legacy POPs, micro- and nanoplastics, and contaminants of emerging interest. Concomitant exposure to these synthetic chemicals may pose a much more serious threat than the Se depletion. Unfortunately, as shown by the literature data summarized in this review, the most exposed populations are those living in the NW basin, the main feeding and reproductive area for most Mediterranean cetaceans, declared a sanctuary for their protection since 2002. Thus, while emphasizing the adoption of all available approaches to mitigate anthropogenic pressure with fishing and maritime traffic, it is recommended to direct future research efforts towards the assessment of possible biological effects, at the individual and population levels, of chronic and simultaneous exposure to Hg, legacy POPs, contaminants of emerging interest, and microplastics.

Warming-Induced Vegetation Greening May Aggravate Soil Mercury Levels Worldwide.

Mercury, a neurotoxic substance, circulates globally, significantly stored in soils through atmospheric deposition and plant decay. Despite being deposited, mercury can be remobilized and released into the atmosphere and water, enhancing its global cycle. Recent research suggests that climate warming may amplify the remobilization of soil mercury, facilitating its incorporation into food webs that humans exploit. However, the potential geospatial feedback of soil mercury levels in response to warming remains unclear. By leveraging up-to-date soil measurements and observation-driven models, we determined the amount of mercury stored in global 0-100 cm soils to be 4.3 Tg (interquartile range: 2.5-6.3 Tg). Furthermore, our analysis indicates that warming likely aggravates global soil mercury levels, particularly in many temperate areas in East Asia, North Europe, and North America (>20 ng g-1 increase by 2100) due to warming-induced vegetation greening. Critically, observation-driven models raise the possibility that implementing ambitious mercury-emission-control schemes alone may be insufficient to counterbalance the positive feedback of soil mercury concentration, while process-based biogeochemical modeling demonstrates consistent patterns that reinforce this concern. These findings hold broad implications; for example, such feedback may catalyze mercury remobilization in land-ocean continuums and exacerbate human risks, stressing the necessity for continued reductions in greenhouse gas and mercury emissions.

Variations in methylmercury contamination levels and associated health risks in different fish species across three coastal bays in China

The growing atmospheric mercury (Hg) emissions in China have raised ongoing concerns regarding contamination in marine fish. To better understand the pollution patterns and associated risks, we examined methylmercury (MeHg) content in demersal and pelagic fish from four commonly found families in three geographically distinct bays along the Chinese coast. We identified significant spatial variations in MeHg levels within the same fish family across regions. Specifically, fish collected from the Beibu Gulf in the South China Sea consistently exhibited significantly higher MeHg levels compared to those from the Laizhou Bay in the Northeast and/or Haizhou Bay in the East of China. In contrast, MeHg levels in fish collected from Haizhou Bay consistently remained the lowest. Within each region, we observed significantly higher MeHg concentrations in demersal species compared to pelagic species. This trend was particularly evident in fish species including bartail flathead (Platycephalus indicus), small-scale tongue sole (Cynoglossus microlepis) and greater lizardfish (Saurida tumbil) from the Beibu Gulf (0.50, 0.21, and 0.18 mg/kg dw, respectively), as well as bartail flathead and slender lizardfish (Saurida elongata) from Laizhou Bay (0.09 and 0.12 mg/kg dw, respectively). By comparison, MeHg content in silver pomfret (Pampus argenteus) from all three regions consistently remained relatively lower than in other species. Using target hazardous quotient (THQ) calculations, we estimated potential health risks in local populations associated with the consumption of the studied fish species. Our results showed a lack of apparent health risks to local residents, as all THQ values obtained from the three regions fell within the safe limits (0.02–0.94). However, it remains important to conduct additional assessments and spatiotemporal monitoring that encompass a broader range of species and regions.

Hollow tubular MnOx prepared by flame annealing with cotton fiber as sacrificial template and its applications for Hg0 adsorption in flue gas

The mass discharge of mercury from coal-fired power plant has caused great harm, abating mercury emissions is of preoccupation for protecting public environmental safety and human health. Metal oxides are often used for Hg0 removal in the flue gas. In this paper, a hollow tubular MnOx(MnCot) was successfully prepared by rapid flame annealing using cotton fiber as a sacrificial template. The MnCot were then well characterized and tested for its capability for Hg0 removal in flue gas. The results indicate that the flame assisted synthesis method for rapidly prototyping metal oxides with typical structures is achievable. The hollow tubular structure of the cotton fiber is well reprinted with good crystallization of Mn3O4. The inner diameter of the hollow tubular MnCot is about 10 μm, and the thickness of the tube is about 1 μm. The Hg0 removal efficiency on MnCot can be maintained as high as 90 % under simulated flue gas atmosphere below 240°C. O2 and NO have a positive effect on the Hg0 removal, which can act as the fresh active sits thus enhancing its capability for Hg0 removal. However, the presence of SO2 will result in the surface sulfation on MnCot, thus deteriorating its capability for Hg0 removal. Further, the competitive adsorption between SO2 and Hg0 on the material will also weaken its capability for Hg0 removal. The hollow tubular MnOx rapidly prepared by one-step flame annealing has a good industrial application potential for Hg0 removal in coal-fired flue gas.

Mercury Discharge Inventory Based on Sewage Treatment Process in China

Mercury pollution is a serious public health problem. China’s extensive use and reliance on mercury has led to water pollution, particularly the presence of methylmercury in water. Estimating total mercury emissions from wastewater in China is challenging due to the large amount and wide range of emissions. An estimation model for total mercury content in sewage in China was established by establishing a relationship between sewage treatment volume, mercury content in effluent after sewage treatment, and the data of sludge production and mercury content in the sewage treatment plant. It was determined that only 3% of mercury entered the air during sewage treatment, 27.5% of mercury entered the effluent, and about 69.5% of mercury entered the sludge, based on the treatment of existing wastewater treatment plants in China. From 2002 to 2021, the average annual sewage mercury emission in China was 32.07 Mg, and the emissions were higher in densely populated and economically developed provinces such as Beijing, Shandong, Hebei, and Guangdong. By 2025, China’s mercury emissions are projected to reach 55.41 Mg. By 2035, China’s mercury emissions are projected to reach 49.3 Mg.

Geographic Drivers of Mercury Entry into Aquatic Food Webs Revealed by Mercury Stable Isotopes in Dragonfly Larvae.

Atmospheric mercury (Hg) emissions and subsequent transport and deposition are major concerns within protected lands, including national parks, where Hg can bioaccumulate to levels detrimental to human and wildlife health. Despite this risk to biological resources, there is limited understanding of the relative importance of different Hg sources and delivery pathways within the protected regions. Here, we used Hg stable isotope measurements within a single aquatic bioindicator, dragonfly larvae, to determine if these tracers can resolve spatial patterns in Hg sources, delivery mechanisms, and aquatic cycling at a national scale. Mercury isotope values in dragonfly tissues varied among habitat types (e.g., lentic, lotic, and wetland) and geographic location. Photochemical-derived isotope fractionation was habitat-dependent and influenced by factors that impact light penetration directly or indirectly, including dissolved organic matter, canopy cover, and total phosphorus. Strong patterns for Δ200Hg emerged in the western United States, highlighting the relative importance of wet deposition sources in arid regions in contrast to dry deposition delivery in forested regions. This work demonstrates the efficacy of dragonfly larvae as biosentinels for Hg isotope studies due to their ubiquity across freshwater ecosystems and ability to track variation in Hg sources and processing attributed to small-scale habitat and large-scale regional patterns.