Hg Emissions Research Articles

Aptamer-functionalized and silver-coated polydopamine-copper hybrid nanoflower adsorbent embedded with magnetic nanoparticles for efficient mercury removal

Mercury (Hg) emissions are increasing annually owing to rapid global industrialization. Hg poisoning can severely affect the human body owing to its persistence and bioaccumulation. In this study, hybrid nanoflowers (NFs) were synthesized by promoting the formation of primary copper-phosphate crystals coordinated with polydopamine (PDA) and Fe3O4 magnetic nanoparticles (MNPs), followed by coating with silver nanoparticles on the surface of the NFs (Ag-MNP-PDA-Cu NFs). The results suggest that the hierarchical structure of the NFs enabled a large surface area with nanosized pores, which were exploited for Hg adsorption. The adsorbed Hg ions could be further eliminated from the solution based on the magnetic characteristics of the NFs. Additionally, hybrid NFs functionalized with Hg2+-binding aptamers (Apt-Ag-MNP-PDA-Cu NFs) were prepared based on the silver–sulfur interactions between the Ag-MNP-PDA-Cu NFs and thiol-modified aptamers. The performance of both adsorbents demonstrated that the immobilization of Hg2+-binding aptamers significantly improved the elimination of Hg from solution. The Hg2+ adsorption isotherm of the Apt-Ag-MNP-PDA-Cu NFs followed the Dubinin–Radushkevich model, with a maximum adsorption capacity of 1073.19 mg/g. The Apt-Ag-MNP-PDA-Cu NFs adsorbed greater amounts of Hg2+ than the non-functionalized NFs at the same concentrations, which confirmed that the functionalization of Hg2+-binding aptamers on the NFs improved the Hg2+ removal performance. The results suggest that Apt-Ag-MNP-PDA-Cu NFs could serve as an efficient Hg-removing adsorbent, possibly by providing binding sites for the formation of T-Hg2+-T complexes.

Characteristics of Hg concentrations and isotopes in terrestrial and marine facies across the end-Permian mass extinction

The end Permian mass extinction (EPME) is the greatest among the “Big Five” extinctions of the Phanerozoic, and is believed to have been triggered primarily by the Siberian Traps Large Igneous Province (STLIP). This hypothesis is supported by the temporal correlation of STLIP with the EPME by radiometric ages and Hg enrichments in sedimentary rocks. However, how signatures of volcanic Hg emissions are preserved in sediments, and how this may vary from deep basin to shelf to terrestrial successions, remain unclear. To examine variability in the Hg record in different environments, we systematically measured organic carbon isotopes, Hg concentrations and isotopes, major elements, and total organic carbon (TOC) contents from: 1) a terrestrial section at Chahe, 2) a marine-nonmarine transitional section at Jinzhong both in Guizhou Province, Southwest China. Results show that Hg versus TOC and Hg versus Al exhibit no correlation through the terrestrial section at Chahe, whereas there is positive correlation in the transitional Jinzhong section. These relationships indicate that organic matter and clay minerals would not affect Hg fluctuations on land, but dominates Hg sequestration in transitional settings. Thus, Hg/TOC along with Hg/Al ratios were able to be employed to recognize abnormal Hg deposition in Jinzhong, and Hg concentrations were utilized to examine records of Hg enrichments in Chahe. The studied sections all show synchronous changes between carbon isotopic perturbations and Hg deposition events with first Hg enrichment and associated negative carbon isotopic negative excursion coinciding with terrestrial ecological disturbance and with a second Hg enrichment corresponding to the largest carbon isotopic negative excursion and marine biological crisis. These trends across the Permian-Triassic boundary are also observed in other 13 sections around the world, indicating a common source that injected massive CO 2 and Hg, impacting the global C and Hg cycles. Hg isotope (Δ 199 Hg values) of the first peak in Hg concentrations have similar characteristics in the terrestrial Chahe and transitional Jinzhong sections along with other sections (e.g., Shangsi and Chaohu in South China, Guryul Ravine section in India and Buchanan Lake section in Canada), all showing positive values, indicative of predominantly atmospheric-derived volcanic Hg. In contrast, Δ 199 Hg values at the second Hg peak, corresponding to the marine extinction horizon in Chahe and Jinzhong, are negative. This relationship indicates an elevated involvement of terrestrial sourced Hg into the terrestrial or nearshore aquatic realm due to increased weathering after the collapse of terrestrial ecosystem. Our study suggests that the STLIP could have two pulses of volatile eruptions that released massive CO 2 and Hg, resulting in two pulses of Hg enrichments coupled with negative carbon isotopic excursions coinciding with end Permian terrestrial and marine extinction events. • Two pulses of Hg enrichments coinciding with the end Permian terrestrial and marine extinction events • Positive Δ 199 Hg values at the first Hg enrichment, indicate a predominant atmospheric-derived signature of volcanic Hg • Δ 199 Hg values at the second Hg peak are negative, indicating an elevated involvement of terrestrial sourced Hg.

In-line measurement of exhaust mercury emissions by an instrumented light-duty vehicle using both on-road and test track experiments

The initial purpose of this study has been to develop an instrumental platform for monitoring mercury (Hg) emissions from vehicle exhausts under actual traffic conditions. The platform was then mounted onto a fully-instrumented passenger car to identify emission proxies and factors governing the emissions of gaseous elemental Hg (GeM) and its complementary fraction (GdPM). Data obtained from the road were complemented by data acquired on a test track at either stabilized speeds or well-characterized speed variations. GeM emissions increased overall with both driving speed and fuel consumption; nonetheless, they were influenced by the sequence of accelerations and duration associated with the preceding idling or low-speed driving situations. GdPM emissions varied considerably over the course of trips or track tests, with medians ranging from 7% to 70% of the total Hg emissions stemming from fuel. Such high percentages could be explained by a series of redox reactions, whose kinetics and yield were influenced as much by exhaust gas temperature as by driving conditions or the exhaust system structural configuration. Lastly, an analysis of the GeM and GdPM signals showed that urban cores constitute emission hotspots during rush hour when handling low-speed driving and stop-and-go traffic.

Impact of Athabasca oil sands operations on mercury levels in air and deposition

Abstract. Oil sands upgrading facilities in the Athabasca oil sands region (AOSR) in Alberta, Canada, have been reporting mercury (Hg) emissions to public government databases (National Pollutant Release Inventory (NPRI)) since the year 2000, yet the relative contribution of these emissions to ambient Hg deposition remains unknown. The impact of oil sands emissions (OSE) on Hg levels in and around the AOSR, relative to contributions from global (anthropogenic, geogenic and legacy) emissions and regional biomass burning emissions (BBE), was assessed using a global 3D-process-based Hg model, GEM-MACH-Hg, from 2012 to 2015. In addition, the relative importance of year-to-year changes in Hg emissions from the above sources and meteorological conditions to inter-annual variations in Hg deposition was examined. Surface air concentrations of Hg species and annual snowpack Hg loadings simulated by the model were found comparable to measured levels in the AOSR, suggesting consistency between reported Hg emissions from oil sands activities and Hg levels in the region. As a result of global-scale transport and the long lifetime of gaseous elemental Hg (Hg(0)), surface air concentrations of Hg(0) in the AOSR reflected the background Hg(0) levels in Canada. By comparison, average air concentrations of total oxidized Hg (efficiently deposited Hg species) in the AOSR were elevated up to 60 % within 50 km of the oil sands Hg emission sources. Hg emissions from wildfire events led to episodes of high ambient Hg(0) concentrations and deposition enrichments in northern Alberta, including the AOSR, during the burning season. Hg deposition fluxes in the AOSR were within the range of the deposition fluxes measured for the entire province of Alberta. On a broad spatial scale, contribution from imported Hg from global sources dominated the annual background Hg deposition in the AOSR, with present-day global anthropogenic emissions contributing to 40 % (< 1 % from Canada excluding OSE) and geogenic and legacy emissions contributing to 60 % of the background Hg deposition. In contrast, oil sands Hg emissions were responsible for significant enhancements in Hg deposition in the immediate vicinity of oil sands Hg emission sources, which were ∼ 10 times larger in winter than summer (250 %–350 % in winter and ∼ 35 % in summer within 10 km of OSE, 2012–2013). The spatial extent of the influence of oil sands emissions on Hg deposition was also greater in winter relative to summer (∼ 100 km vs. 30 km from Hg-emitting facilities). In addition, inter-annual changes in meteorological conditions and oil sands emissions also led to significantly higher inter-annual variations in wintertime Hg deposition compared to summer. In 2015, within 10 km of major oil sands sources, relative to 2012, Hg deposition declined by 46 % in winter but 22 % annually, due to a larger OSE-led reduction in wintertime deposition. Inter-annual variations in meteorological conditions were found to both exacerbate and diminish the impacts of OSE on Hg deposition in the AOSR, which can confound the interpretation of trends in short-term environmental Hg monitoring data. Hg runoff in spring flood, comprising the majority of annual Hg runoff, is mainly derived from seasonal snowpack Hg loadings and mobilization of Hg deposited in surface soils, both of which are sensitive to Hg emissions from oil sands developments in the proximity of sources. Model results suggest that sustained efforts to reduce anthropogenic Hg emissions from both global and oil sands sources are required to reduce Hg deposition in the AOSR.

Development of CuInS2/g-C3N4 nanolayer for efficient adsorption of elemental mercury from coal combustion flue gas

The flue gas with high concentration of mercury is often encountered in coal combustion flue gas treatment, so sorbents with sufficient adsorption capacity is urgently required to capture and immobilize mercury. CuInS2/g-C3N4 (CIS/GCN), synthesized by one step hydrothermal method, was developed as a suitable candidate sorbent to replace current commercial sorbents to remove Hg0 from flue gas, as a co-benefit of electrostatistic precipitator (ESP). Due to the abundance of surface metal cation vacancies and sulfur sites, compared to most sorbents, CIS/GCN exhibited excellent Hg0 adsorption capacity reaching upto 27.48 mg g−1, and its removal efficiency arrived at 100% at 120 °C. Besides, CIS/GCN depicted outstanding Hg0 removal capabilities in simulated flue gas (SFG) and a wide temperature range (40–160 °C). A long-term evaluation of 10 h was carried out on an optimal sorbent, and the sample adsorption capacity remained superb. Furthermore, gas-phase Hg0 was firstly captured by metal cation vacancies and diffused along the surface, the surface diffusion rate constant was calculated as 2.54 × 10−32 s−1, and then combined with S22− over the sulfur sites to form α-HgS and β-HgS, which were the most stable mercury compounds, XPS analysis and TPD experiment further demonstrated this process. With above outstanding Hg0 adsorption performance, CIS/GCN sorbents were authenticated to be a forceful candidate for current commercial activated carbon for Hg0 immobilization. This work is to provide methods for controlling the emission of Hg0 from coal combustion flue gas in industrial application.

Development of an anthropogenic atmospheric mercury emissions inventory in Thailand in 2018

Mercury (Hg) is a highly toxic pollutant characterized by its long-range transport in the atmosphere. In the present study, the atmospheric Hg emission inventory in Thailand was developed using a bottom-up approach. To reflect the emitting behaviors of various Hg sources in Thailand in 2018, activity data specific to individual sources were collected, and emission factors were obtained from local sources or adapted from the literature with proper adjustments. It was found that about 4,337.8 kg of anthropogenic Hg was emitted: 52 % from biomass open burning and 40 % from combustion sources. Mercury speciation was also investigated. Hg0 was found to be dominant at 73 %, followed by Hg2+ at 18 % and HgP at 9 %. Maps were produced using the Spatial Geographic Information System, which showed that the emissions were relatively dense in the Central region of Thailand where most industrial activities take place and in the Northern and Northwestern regions as a result of biomass open burning. Hg emissions were also observed to mainly take place during the early months of the year, particularly in March and April. These two months were determined to account for 47 % of the total annual emissions of Hg, mostly due to increased combustion activities and biomass open burning. The output of the present work is a Hg emission database that can serve as model to investigate the status of Hg and the risks it poses to human health and ecosystems as well as support policy makers in developing emission control strategies.

Resource utilization of natural pyrite (FeS2) as the tailings after flotation of natural sphalerite (ZnS) for reclaiming high concentrations of gaseous Hg0 from Zn smelting flue gas

Reducing Hg emissions from Zn smelting flue gas (Zn-SFG) is rigorously stipulated by the Minamata Convention. Currently, a little natural pyrite (FeS2) as the tailings after flotation of natural sphalerite (ZnS) is often regarded as solid wastes and discarded; therefore, another utilization of these natural FeS2 is preferable. In this study, magnetic pyrrhotite (Fe1-xS), formed by heat treatment of natural FeS2, was exploited to reclaim gaseous Hg0 from Zn-SFG. Magnetic Fe1-xS displayed outstanding ability to capture gaseous Hg0 due to the formation of surface new unsaturation coordination sites for gaseous Hg0 physical adsorption. Additionally, magnetic Fe1-xS can be separated magnetically from Zn-SFG after gaseous Hg0 capture owing to its acceptable magnetism. Furthermore, both the abundant S resources emitted from the transformation of natural FeS2 to magnetic Fe1-xS and those in magnetic Fe1-xS after gaseous Hg0 capture can be used for H2SO4 production. Moreover, the vast majority of gaseous Hg0 in Zn-SFG can be ultimately reclaimed as liquid Hg0 by the condensation unit in Zn smelteries. Therefore, magnetic Fe1-xS offered unparalleled advantages in gaseous Hg0 recovery from Zn-SFG, double as a feasible method for fully exploiting the resource utilization value of natural FeS2 as the tailings after flotation of natural ZnS.

Mercury Inputs Into Eastern China Seas Revealed by Mercury Isotope Variations in Sediment Cores

AbstractThe mercury (Hg) loadings to the coastal regions of China have significantly increased in the last decades, and it is thus critical to unravel the input pathway and historical influx of these Hg. Here, concentrations and isotope compositions of Hg in three sediment cores collected from different mud areas of eastern China seas were comprehensively analyzed to investigate the spatial and temporal Hg inputs. The sediment core from nearshore mud area had distinctly higher δ202Hg and lower Δ199Hg values than those from offshore mud area, exhibiting an obvious difference in dominant Hg sources (land‐based vs. atmospheric). An isotope mixing model on basis of Hg isotope signatures of these cores revealed that the contributions of Hg sources varied significantly not only among different sites but also among different periods. Rapid development of industrialization and urbanization since the 1980s have significantly increased Hg especially industrial Hg inputs into eastern China seas. Our study suggests that the central mud area of Yellow Sea could well record the historical influxes of different Hg sources especially atmospheric Hg, as well as historical Hg emission events like industrialization/urbanization and modern Chinese wars, which would contribute to reconstruct the chronology of Hg inputs into eastern China seas.

Rapid temporal decline of mercury in Greenland halibut (Reinhardtius hippoglossoides)

Mercury (Hg) pollution in the ocean is an issue of global concern, however bioaccumulation regimes of this ubiquitous pollutant in marine apex predators have important knowledge gaps. Our fish length and stable isotope (δ15N and δ13C) normalized data of Greenland halibut (GH) (Reinhardtius hippoglossoides) showed that Hg bioaccumulation in fillet tissue decreased by ~35–50 %, over a ten-year period from 2006 to 2015 (n = 7 individual sampling years). Hg was predominantly in the methylmercury form (>77 %). Results from a Bayesian information theoretic model showed that GH Hg concentrations decreased with time and its associated declines in Hg air emissions, estimated trophic position, and a potentially lower degree of demersal prey use as indicated by temporal trend shifts in nitrogen (δ15N) and carbon (δ13C) stable isotope values. GH trophic shifts accounted for about one third of the observed temporal reduction in Hg. Our study demonstrates the importance of simultaneously considering Hg emissions, food web dynamics and trophic shifts as important drivers of Hg bioaccumulation in a marine, deep water fish species and highlights the effectiveness of Hg regulations on ocean apex predator Hg concentrations and overall seafood safety.

Characteristics of gaseous elemental mercury and its corresponding source contributions to regional transport in Hefei, China

The characteristics of atmospheric gaseous elemental mercury (GEM) in Hefei, China in winter, spring, and autumn 2016 were investigated in this study. Higher GEM concentrations in spring were associated with more abundant anthropogenic emissions and biomass burning before spring plowing. GEM concentrations in the three seasons decreased significantly compared to 2013–2014 levels (22.2%–49.2%), which may to some extent reflect the effectiveness of air quality control measures for coordinated control of atmospheric Hg. The Potential Source Contribution Function (PSCF) analysis show that areas to the north are major contributors of GEM to Hefei in winter because of the effect of the East Asian winter monsoon. In spring and autumn, the major contributors are primarily concentrated in regions to the south. The relative contributions of three categories of anthropogenic GEM sources to their regional transports in each season was further quantified in this study. The results showed similar patterns. Industrial sources accounted for the highest contribution (56%–59.6%), followed by intentional use and product waste associated sectors (24.5%–27.1%), and stationary combustion sources (15.6%–16.9%), implying that control of industrial Hg emissions should be prioritized in future measures. This study compared the simulated results of GEM by the GEOS-Chem model with the field observations. It is found that the GEOS-Chem model significantly overestimated GEM by 75% in general, suggesting that timely update of mercury emission inventory data is needed to improve the accuracy of atmospheric mercury simulations under the background of implementing “Minamata Convention” and a series of air pollution control policies in the future.

An Integrated Investigation of Atmospheric Gaseous Elemental Mercury Transport and Dispersion Around a Chlor-Alkali Plant in the Ossola Valley (Italian Central Alps).

We present the first assessment of atmospheric pollution by mercury (Hg) in an industrialized area located in the Ossola Valley (Italian Central Alps), in close proximity to the Toce River. The study area suffers from a level of Hg contamination due to a Hg cell chlor-alkali plant operating from 1915 to the end of 2017. We measured gaseous elemental Hg (GEM) levels by means of a portable Hg analyzer during car surveys between autumn 2018 and summer 2020. Moreover, we assessed the long-term dispersion pattern of atmospheric Hg by analyzing the total Hg concentration in samples of lichens collected in the Ossola Valley. High values of GEM concentrations (1112 ng m−3) up to three orders of magnitude higher than the typical terrestrial background concentration in the northern hemisphere were measured in the proximity of the chlor-alkali plant. Hg concentrations in lichens ranged from 142 ng g−1 at sampling sites located north of the chlor-alkali plant to 624 ng g−1 in lichens collected south of the chlor-alkali plant. A north-south gradient of Hg accumulation in lichens along the Ossola Valley channel was observed, highlighting that the area located south of the chlor-alkali plant is more exposed to the dispersion of Hg emitted into the atmosphere from the industrial site. Long-term studies on Hg emission and dispersion in the Ossola Valley are needed to better assess potential impact on ecosystems and human health.

Mercury distribution in the East Himalayas: Elevational patterns in soils and non-volant small mammals

Mercury (Hg), as a global pollutant, its contamination has been documented in environmental compartments of the Himalayan region. However, little research exists regarding to Hg accumulation in terrestrial wildlife, as well as its driving factors. In this study, surface soil and small mammals were collected in the Lebu Valley, East Himalayas of China, in order to measure the uptake of the long-distance transported Hg along an elevational gradient approximately from 2300 to 5000 m a.s.l. The soil Hg concentrations were measured and predicted mostly by vegetation type as well as soil organic matter, while the Hg in hair of small mammals (Muridae and Cricetidae) showed deeply influenced by soil Hg. Notably, combined with the field survey data, soil and hair Hg were both enhanced in low and mid-elevations, which overlapped the distribution ranges of a majority of mammals. Overall, this indicates that Hg contamination in low- and mid-elevations poses a potential threat to the top predators that consuming small mammals directly or indirectly. Furthermore, our data advances the understanding of Hg dynamics in remote, high mountain ecosystems and provides baseline data for biomonitoring for reduction of Hg emission globally.

Co-regulation of dispersion, exposure and defect sites on CeO2 (111) surface for catalytic oxidation of Hg0

The additional cost of Hg0 capture in coal-fired power plants has facilitated the demand for environmental pollutants mitigation material for Hg0 oxidation to Hg2+ for an ultra-low Hg emission technology. Herein, a suite of CeO2-based catalysts were investigated aiming at ultra-low gaseous Hg0 emission at coal-fired power stations. Gaseous elemental mercury is feasible to be catalytically oxidized to Hg2+. The co-regulated dispersion, exposure and defect sites on CeO2 (111) surface with 2 wt% Ce and 8 wt% Mo compositions on γ-Al2O3 was found to be the most promising catalyst demonstrating a high catalytic oxidation efficiency, a broad operating temperature range and a low activation energy. Specifically, it is shown that the oxidation of Hg0 on the Ce-based catalysts can be enhanced by the addition of Mo (up to 8 wt%) via promoting the CeO2 (111) surface dispersion and exposure. Moreover, insights into the Ce and Mo synergistic interactions showed that it facilitated the formation of defect-containing surface sites. Besides, the co-regulation of dispersion, exposure and defect sites on CeO2 (111) surface was further studied by DFT calculations. This study provides a feasible approach in optimization of CeO2-based catalysts for catalytic oxidation of Hg0 to achieve efficient removal of environmental pollutants.

The GOS4M Knowledge Hub: A web-based effectiveness evaluation platform in support of the Minamata Convention on Mercury

The Minamata Convention on Mercury was established to reduce the pressure on the environment caused by mercury by significantly reducing its emissions from anthropogenic activities. However, knowledge gaps still exist concerning emission inventories, emission factors and their integration in modelling frameworks. In addition, tools to facilitate communication between decision-makers and research groups providing measurement and modelling data are still scarce. This work presents the GOS4M Knowledge Hub, a public web application that provides an interactive and user friendly experience to access state-of-the-art modelling tools and data available in the literature. The Knowledge Hub currently integrates a Chemical Transport Model emulator, HERMES, coupled with a biogeochemical model, although it has been designed to house and deploy any number of different modelling components. Using the integrated dashboard, non-experts can perturb mercury releases from different anthropogenic emission sectors, simulating, for example, the application of Best Available Technologies, and then visualise in real-time the short- and long-term effects of the consequent reductions within a source-receptor framework. The dashboard also furnishes an estimate of the statistical significance of the changes in the model results. The analysis of a set of anthropogenic Hg emission reduction scenarios shows how an internationally coordinated effort would be necessary to achieve significant policy goals. It is important to note that the GOS4M Knowledge Hub yields the analysis presented here in a matter of seconds, compared to the days or weeks required by traditional modelling tools.

Hourly emission inventories for air toxic emissions for eastern Australian electricity generators derived from energy distribution data

Emission inventories are a fundamental input for atmospheric chemical transport models in order to accurately simulate air pollution and its impacts. In Australia, emission inventories are currently not available for electricity generators at high temporal and spatial resolutions. In this study, a new high spatial and temporal resolution inventory for Australian power plant emissions has been developed. The emissions from coal- and gas-fired power plants have been estimated using 5-min electricity generation time-series data and emission factors. The emissions are estimated from 2010 to 2019 for sulfur dioxide (\(\hbox {SO}_2\)), nitrogen oxide (\(\hbox {NO}_{2}\)), particulate matter (PM) and mercury (Hg). We estimate that, for 2019, the coal-fired power plants in Australia emitted significant amounts of \(\hbox {SO}_2\) (485.7 kTonne) and \(\hbox {NO}_{2}\) (452 kTonne), as there are no sulfur dioxide or nitrogen oxide controls in place. In contrast, PM emissions are mitigated by particulate matter control devices and coal-fired power plants emit an estimated 27.48 and 13.46 kTonne of \(\hbox {PM}_{10}\) and \(\hbox {PM}_{2.5}\), respectively. Coal-fired power plants were responsible for an estimated 3.13 tonnes of Hg emissions. Gas-fired plant emissions are significantly lower than coal-fired power emissions for all pollutants. Temporal analysis showed that coal- and gas-fired power plant emissions vary quite markedly during the day and over the week. There is a strong diurnal cycle in the gas-fired emissions, which, if ignored by assuming constant emissions (such as is routinely done), will lead to significant errors in modeled air pollution.

Mercury atmospheric emission, deposition and isotopic fingerprinting from major coal-fired power plants in Australia: Insights from palaeo-environmental analysis from sediment cores

Despite Australia's high reliance on coal for electricity generation, no study has addressed the extent to which mercury (Hg) deposition has increased since the commissioning of coal-fired power plants. We present stratigraphic data from lake sediments in the Hunter Valley (New South Wales) and Latrobe Valley (Victoria), where a significant proportion of Australia's electricity is generated via coal combustion. Mercury deposition in lake sediments increased in the 1970s with the commissioning of coal-fired power plants, by a factor of 2.9-times in sediments of Lake Glenbawn (Hunter Valley) and 14-times in Traralgon Reservoir (Latrobe Valley). Sediments deposited after the commissioning of power plants have distinct Hg isotope compositions, similar to those of combusted coals. Mercury emission, estimated using an atmospheric model (CALPUFF), was higher in the Latrobe Valley than in the Hunter Valley. This is a result of higher Hg concentrations in lignite coal, lax regulation and older pollution-control technologies adopted by coal-fired power plants in the Latrobe Valley. Near-source deposition of Hg in Australia is significantly higher than North America and Europe, where better emission controls (e.g. wet flue gas desulfurization) have been in effect for decades. The challenge for Australia in years to come will be to ratify the Minamata Convention and develop better regulation policies to reduce Hg emissions.

Global Economic Structure Transition Boosts Atmospheric Mercury Emissions in China

AbstractAs the “world factory,” China has the most massive anthropogenic atmospheric mercury (Hg) emissions in the world along with its intense production activities. The development of global society and economy, including technology development, consumption behavior evolution, population growth, and so on, would significantly affect China's production and thus the Hg emissions. Here we uncover critical global socioeconomic drivers of atmospheric Hg emission changes in China during 2005–2015. Results show that the transition of global economic structures (i.e., production and final demand structures) caused 179 tons of increase in China's atmospheric Hg emissions during this period if other factors remained constant, while the transition of foreign economic structures contributed as much as 83% (149 tons). More importantly, for the first time, we reveal the crucial role of production structure transition in foreign nations. The cumulative effect of foreign production structure transition during this period (93 tons) was larger than that of foreign final demand structure transition (56 tons). It is also far more extensive than the cumulative effect of China's production structure transition (9.5 tons). Previous studies on China's atmospheric Hg emissions driven by global final demand focused more on optimizing consumption behaviors. However, this study proves the significance of a greener global production structure for reducing anthropogenic atmospheric Hg emissions in China, thus implementing the Minamata Convention on Mercury.

Global health effects of future atmospheric mercury emissions

Mercury is a potent neurotoxin that poses health risks to the global population. Anthropogenic mercury emissions to the atmosphere are projected to decrease in the future due to enhanced policy efforts such as the Minamata Convention, a legally-binding international treaty entered into force in 2017. Here, we report the development of a comprehensive climate-atmosphere-land-ocean-ecosystem and exposure-risk model framework for mercury and its application to project the health effects of future atmospheric emissions. Our results show that the accumulated health effects associated with mercury exposure during 2010–2050 are $19 (95% confidence interval: 4.7–54) trillion (2020 USD) realized to 2050 (3% discount rate) for the current policy scenario. Our results suggest a substantial increase in global human health cost if emission reduction actions are delayed. This comprehensive modeling approach provides a much-needed tool to help parties to evaluate the effectiveness of Hg emission controls as required by the Minamata Convention.

The reallocation effect of China's provincial power transmission and trade on regional heavy metal emissions

SummaryCoal-fired power plants (CFPPs) are key point sources to atmospheric heavy metal (HM) emissions in China. Unevenly distributed CFPPs lead to large-scale interregional power transmission, as well as corresponding environmental emissions transfer. However, the effect of power transmission on HM reallocation remains poorly understood. Here, we traced HM (including Hg, As, Se, Pb, Cd, and Cr) emission flows through electricity transmission and regional trade and calculated China's multi-perspective electricity-related HM emissions from 2010 to 2015. Results show that in 2015, power transmission and regional trade caused 226.5 t (14% of total emissions) and 453.6 t (28%) of HM emission flows, respectively, leading to great differences in provincial HM emissions under different perspectives (e.g., Beijing's consumption-based emission was 15.5 times higher than the city's production-based emission in 2015). Our study provides valuable insights for fairly allocating provincial HM emission reduction responsibility and formulating synergistic emission mitigation strategies among regions.

Preliminary Assessment of Heavy Metals in Refuse Derived Fuel (RDF) for Thermochemical Conversion

Thermochemical conversion of raw municipal solid waste (MSW) is continuously growing in the context of contemporary technology. The quality of MSW needs an improved analysis to enhance the choice of energy exploitation and environmental assessment of fly and bottom ashes associated with thermochemical conversion. MSW was collected from solid waste disposal facilities (SWDF) in Cape Town in order to investigate heavy metal distributions in MSW obtained from SWDF. The MSW was pre-treated to improve its quality. The 7700 Series quadrupole ICP-MS solution method was used to determine the concentrations and distributions of some heavy metals from SWDF in Cape Town. This study assessed and quantified the distributions of heavy metal in MSW in the city of Cape Town. The accumulation of high concentrations of heavy metals in bottom ash residue from thermochemical conversion could be a good remedy for heavy metals control. High transfer coefficients of heavy metals were observed, and the heavy metals were mainly transferred to the bottom ash. Heavy metals such as Cd, Cu, Pb, and Zn in bottom ash are regarded as relatively unstable with the highest concentrations of Cu and Zn 1295 mg/Kg and 3347 mg/Kg, respectively. The heavy metals (especially Pb, Zn and Hg) emissions were technically monitored and controlled from escaping into the urban air-sheds atmosphere and prevented from their consequential secondary environmental and health implications.