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The re-emission and subsurface migration of legacy mercury (Hg) are not well understood due to limited knowledge of the driving processes. To investigate these processes at a decommissioned chlor-alkali plant, we used mercury stable isotopes and chemical speciation analysis. The isotopic composition of volatilized Hg(0) was lighter compared to the bulk total Hg (THg) pool in salt-sludge and adjacent surface soil with mean ε202HgHg(0)-THg values of -3.29 and -2.35, respectively. Hg(0) exhibited dichotomous directions (E199HgHg(0)-THg = 0.17 and -0.16) of mass-independent fractionation (MIF) depending on the substrate from which it was emitted. We suggest that the positive MIF enrichment during Hg(0) re-emission from salt-sludge was overall controlled by the photoreduction of Hg(II) primarily ligated by Cl- and/or the evaporation of liquid Hg(0). In contrast, O-bonded Hg(II) species were more important in the adjacent surface soils. The migration of Hg from salt-sludge to subsurface soil associated with selective Hg(II) partitioning and speciation transformation resulted in deep soils depleted in heavy isotopes (δ202Hg = -2.5) and slightly enriched in odd isotopes (Δ199Hg = 0.1). When tracing sources using Hg isotopes, it is important to exercise caution, particularly when dealing with mobilized Hg, as this fraction represents only a small portion of the sources.
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Mercúrio , Mercúrio/análise , Esgotos/análise , Isótopos de Mercúrio/análise , Isótopos/análise , Solo/química , Fracionamento Químico , Monitoramento AmbientalRESUMO
Corn is a crucial crop in China and is widely cultivated in the mercury (Hg) mining region of Guizhou. This study analyzed the Hg content in soil and corn plant samples from the Wuchuan Hg mining area (WCMA) and the surrounding non-Hg mining regions (SNMR). The findings suggest that ongoing ecological rehabilitation and environmental conservation measures in the WCMA have significantly decreased the Hg content in corn kernels. The Hg concentration in different parts of the corn plant varied, being higher in the roots, tassels, and leaves and lower in kernels and stalks. Hg stored in corn plant growing in the WCMA primarily originates from the soil (55.4%), while in the SNMR, it mainly comes from the atmosphere (74.9%). Despite counted only about 7% of the total plant mass, corn roots play a crucial role in soil Hg pollution remediation when corn is used for remediation. Household corn residues burning release about 58.5% and 66.9% of the stored Hg in corn plants growing in the WCMA and the SNMR, respectively, into the atmosphere. Our findings indicate that corn cultivation acts as a reservoir for both soil and atmospheric Hg in the SNMR, while in the WCMA, it serves as a source of atmospheric Hg.
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Mercúrio , Poluentes do Solo , Mercúrio/análise , Zea mays , Poluentes do Solo/análise , Monitoramento Ambiental , Solo/química , China , MineraçãoRESUMO
Green tea has many health benefits and is the most consumed type in China. However, the heavy metals and contaminants in tea can also pose a great risk to human health. In this study, mercury (Hg) concentration in green tea collected from 11 provinces in China was examined. The leaching characteristics of Hg during brewing and the associated exposure to drinkers were also evaluated. Results indicated a low potential of Hg accumulation in green tea. The Hg content of green tea from Wanshan District, Guizhou Province-which has the largest Hg mine in China and is severely contaminated by Hg-could be limited by controlling the harvest time of tea leaves. The average Hg content of green tea from 43 tea production sites in China was only 6.3 ± 6.4 µg/kg dry weight. The brewing experiments of green tea showed that the leaching ratio of Hg was 22.61 ± 7.58% for 40 min of a single brew, and increased to 32.83 ± 12.37% after four rounds (3 min/ round) of brewing. The leaching of Hg from tea leaves was significantly affected by leaching time, temperature, and solid-liquid ratio but not by water hardness. The risk of Hg exposure from green tea intake was found to be very low, with an average hazard quotient (HQ) value of only 1.82 ± 1.85% for a single brew in 40 min and 2.64 ± 2.68% after four rounds of brewing. However, in some highly contaminated areas, with HQ values as high as 43.12 ± 2.41%, green tea intake may still pose a high risk of Hg exposure, and this risk should not be ignored.
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Mercúrio , Poluentes do Solo , China , Monitoramento Ambiental , Humanos , Mercúrio/análise , Poluentes do Solo/análise , CháRESUMO
Cement plants (CPs) are one of the most important anthropogenic sources of mercury (Hg) emissions in China. Over 1000 cement production lines operate in China and use various raw materials; however, little data on Hg emissions is recorded on site. This study investigated a CP in Guizhou Province that uses multiple mining and industrial wastes as part of the circular economy policy. Among the various raw materials, carbide slag had the highest Hg content (2.6 mg/kg) and contributed half of the Hg input. High Hg concentration (27 mg/kg) in the kiln tail dust and a strong Hg enrichment factor (39) was found, which was determined as the ratio of total Hg accumulated within the clinker production process to the daily Hg input from raw materials and fuel. The clinker had negligible Hg (0.001 mg/kg), while the Hg in cement products (0.04 mg/kg) mostly came from additives and retarders. The estimated atmospheric emission factor of Hg from this CP was 161.5 mg Hg/t clinker, which was much higher than those of other CPs in Guizhou that employ low-Hg raw materials. A five-step sequential extraction experiment with kiln tail dust indicates that Hg mainly existed in fraction of F4 (73-96% of the total Hg, possibly as Hg2Cl2) and that some samples had high proportions of water-soluble Hg (up to 21% of the total), which may be easily released into surrounding water bodies and pose high environmental risks. Using low-Hg raw (or alternative raw) materials and conducting proper disposal of kiln tail dust will reduce the environmental risk of Hg from CPs.
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Consumption of mercury (Hg) contaminated vegetable is one important pathway of Hg expose to humans. In this study, Hg contents in a popular vegetable, Houttuynia cordata Thunb. (HCT), and its growing soils in Kaiyang county in Guizhou province of southwest China were investigated. Health risk related to Hg exposure through consumption of this vegetable was evaluated for the first time. Hg contents in HCT were found to be much higher in three towns in western Kaiyang county (42.3 ± 48.2 µg/kg, FW), where former Hg mines located, than that in other towns (7.6 ± 5.0 µg/kg, FW). Hg contents in HCT were also higher than in the other five vegetables (Chinese cabbage, Lettuce, Tomato, Carrot and White radish). Consumption of HCT may account for 37.4-61.1% of total vegetable Hg intake of local people in Kaiyang county. Hg concentration in HCT positively correlated with that in soil (r2 = 0.311, p < 0.01), especially, the labile Hg species (FC1, r2 = 0.796, p < 0.01) and the elemental Hg that is bound to the crystalline oxides (FC3, r2 = 0.711, p < 0.01), and negatively correlated with Hg that is bound to humic and fulvic complexes (FC2, - 0.304). Estimated daily intake (EDI) and target hazard quotient (THQ) results shown that Hg expose risk is much higher for children than adults, likely due to their different eating habits and the amount of snack intake.
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Exposição Dietética/análise , Houttuynia/química , Mercúrio/análise , Poluentes do Solo/análise , Verduras/química , China , Humanos , Substâncias Húmicas/análise , Mineração , Solo/químicaRESUMO
The accumulations of heavy metals in urban soils are derived from natural parent materials and complex anthropogenic emission sources. This paper investigated metal contamination in urban soils at an industry undeveloped city (Haikou) in southern China, an ideal place to quantitatively assess the contribution of metals from different sources. The concentrations of most heavy metals in the urban soils of Haikou were much lower than their guideline values and that of those from other big cities in China. In contrast, the chemical speciation of metals in this study was similar to those from other cities. The spatial distributions of heavy metals and principal component analysis (PCA) revealed that basaltic parent materials, traffic emissions, and coal combustion were the main factors controlling the distribution of metals in the soils. The Pb isotope signatures of the Haikou soils were greatly different from those of the Beijing and Shanghai soils, but similar to those of the Guangzhou soils, suggesting the common sources of Pb in southern China cities. The results of ternary mixing model of Pb isotopes showed that the contributions of Pb from natural background, coal combustion and traffic emission sources were 5.3-82.4% (mean: 39.7 ± 21.1%), 0-85.7% (mean: 25.5 ± 24.6%), and 1.9-64% (mean: 34.8 ± 22.9%), respectively. This suggests that traffic emission is still the most important anthropogenic source of Pb in Haikou.
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Monitoramento Ambiental/métodos , Indústrias , Metais Pesados/análise , Poluentes do Solo/análise , Solo/química , Urbanização , China , Cidades , Carvão Mineral/análise , Isótopos , Análise de Componente PrincipalRESUMO
Smelting of nonferrous metals is an important source of heavy metals in surface soil. The crops/vegetables grown on contaminated soil potentially impose adverse effects on human health. In this study, the contamination level of five heavy metals (Hg, Pb, Zn, Cd and Cu) in ten types of vegetables grown nearby a large scale Pb/Zn smelter in Hunan Province, China and the health risk associated with their consumption are assessed. Based on the data obtained from 52 samples, we find that Pb and Cd contributed to the greatest health risk and leafy vegetables tend to be more contaminated than non-leafy vegetables. Within 4â¯km radius of the smelter, over 75% of vegetable samples exceeded the national food standard for Pb; over 47% exceeded the Cd standard; and 7% exceeded the Hg standard. Heavy metal concentrations in vegetables measured within the 4â¯km radius are on average three times more elevated compared to those found at the control area 15â¯km away. Heavy metals in vegetables have dual sources of root absorption from soil and leaf adsorption from atmosphere. Health risk in terms of the hazard index (HI) at contaminated areas are 3.66 and 3.14 for adults and children, respectively, suggesting adverse health effects would occur. HI for both groups are mainly contributed by Pb (48%) and Cd (40%). Fortunately, vegetable samples collected at the control area are considered safe to consume.
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Produtos Agrícolas/química , Dieta , Exposição Ambiental/análise , Indústrias , Metais Pesados/análise , Solo/química , Verduras/química , Adulto , Poluentes Atmosféricos/efeitos adversos , Poluentes Atmosféricos/análise , Cádmio/efeitos adversos , Cádmio/análise , Criança , China , Cobre/efeitos adversos , Cobre/análise , Exposição Ambiental/efeitos adversos , Poluição Ambiental , Humanos , Chumbo/efeitos adversos , Chumbo/análise , Mercúrio/efeitos adversos , Mercúrio/análise , Metais Pesados/efeitos adversos , Folhas de Planta/química , Raízes de Plantas/química , Medição de Risco , Poluentes do Solo/efeitos adversos , Poluentes do Solo/análise , Zinco/efeitos adversos , Zinco/análiseRESUMO
Long-distance quantum channels capable of transferring quantum states faithfully for unconditionally secure quantum communication have been so far confirmed to be feasible in both fiber and free-space air. However, it remains unclear whether seawater, which covers more than 70% of the earth, can also be utilized, leaving global quantum communication incomplete. Here we experimentally demonstrate that polarization quantum states including general qubits of single photon and entangled states can survive well after travelling through seawater. We perform experiments with seawater collected over a range of 36 kilometers in the Yellow Sea. For single photons at 405 nm in a blue-green window, we obtain an average process fidelity above 98%. For entangled photons at 810nm, albeit very high loss, we observe the violation of Bell inequality with 33 standard deviations. Our results confirm the feasibility of a seawater quantum channel, representing the first step towards underwater quantum communication.
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Lead (Pb) pollution emission from China is becoming a potential worldwide threat. Pb isotopic composition analysis is a useful tool to accurately trace the Pb sources of aerosols in atmosphere. In this study, a comprehensive data set of Pb isotopes for coals, Pb/Zn ores, and fuels from China was presented. The ratios of 206Pb/207Pb and 208Pb/206Pb in the coals were in the range of 1.114-1.383 and 1.791-2.317, similar to those from Europe, Oceania, and South Asia, but different from those from America (p < 0.01). The Pb/Zn ores had 206Pb/207Pb and 208Pb/206Pb in 1.020-1.183 and 2.088-2.309, less radiogenic than the coals. Leaded gasolines showed similar Pb isotopic compositions to Pb/Zn ores, with unleaded gasolines and diesels being mixed sources. The average Pb isotopic ratios of gasolines and diesels were significantly different (p < 0.01) from those of coals in China, leading to the possibility to discriminate Pb in fuels from in coals. Urban aerosols demonstrated similar Pb isotopic compositions to coals, Pb/Zn ores, and fuels in China. After removing the leaded gasoline, the Pb in aerosols is more radiogenic, supporting the heavy contribution of coal combustion to the atmospheric Pb pollution.
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Carvão Mineral , Chumbo , Zinco , Ásia , China , Monitoramento Ambiental , Europa (Continente) , IsótoposRESUMO
The content levels, distribution characteristics, and health risks associated with 15 rare earth elements (REEs) in urban street dust from an industrial city, Zhuzhou, in central China were investigated. The total REE content (∑REE) ranged from 66.1 to 237.4 mg kg-1, with an average of 115.9 mg kg-1, which is lower than that of Chinese background soil and Yangtze river sediment. Average content of the individual REE in street dust decreased in the order Ce > La > Nd > Y > Pr > Sm > Gd > Dy > Er > Yb > Eu > Ho > Tb > Tm > Lu. The chondrite-normalized REE pattern indicated light REE (LREE) enrichment, a relatively steep LREE trend, heavy REE (HREE) depletion, a flat HREE trend, a Eu-negative anomaly and a Ce-positive anomaly. Foremost heavy local soil and to less degree anthropogenic pollution are the main sources of REE present in street dust. Health risk associated with the exposure of REE in street dust was assessed based on the carcinogenic and non-carcinogenic effect and lifetime average daily dose. The obtained cancer and non-cancer risk values prompt for no augmented health hazard. However, children had greater health risks than that of adults.
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Poeira/análise , Poluentes Ambientais/análise , Indústrias , Metais Terras Raras/análise , Saúde da População , Adulto , Criança , China , Monitoramento Ambiental/métodos , Poluentes Ambientais/toxicidade , Humanos , Metais Terras Raras/toxicidade , Medição de Risco , População UrbanaRESUMO
Pleckstrin homology domain-containing family M member 2 (PLEKHM2) is an essential adaptor for lysosomal trafficking and its homozygous truncation have been reported to cause early onset dilated cardiomyopathy (DCM). However, the molecular mechanism of PLEKHM2 deficiency in DCM pathogenesis and progression is poorly understood. Here, we generated an in vitro model of PLEKHM2 knockout (KO) induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) to elucidate the potential pathogenic mechanism of PLEKHM2-deficient cardiomyopathy. PLEKHM2-KO hiPSC-CMs developed disease phenotypes with reduced contractility and impaired calcium handling. Subsequent RNA sequencing (RNA-seq) analysis revealed altered expression of genes involved in mitochondrial function, autophagy and apoptosis in PLEKHM2-KO hiPSC-CMs. Further molecular experiments confirmed PLEKHM2 deficiency impaired autophagy and resulted in accumulation of damaged mitochondria, which triggered increased reactive oxygen species (ROS) levels and decreased mitochondrial membrane potential (Δψm). Importantly, the elevated ROS levels caused oxidative stress-induced damage to nearby healthy mitochondria, resulting in extensive Δψm destabilization, and ultimately leading to impaired mitochondrial function and myocardial contractility. Moreover, ROS inhibition attenuated oxidative stress-induced mitochondrial damage, thereby partially rescued PLEKHM2 deficiency-induced disease phenotypes. Remarkably, PLEKHM2-WT overexpression restored autophagic flux and rescued mitochondrial function and myocardial contractility in PLEKHM2-KO hiPSC-CMs. Taken together, these results suggested that impaired mitochondrial clearance and increased ROS levels play important roles in PLEKHM2-deficient cardiomyopathy, and PLEKHM2-WT overexpression can improve mitochondrial function and rescue PLEKHM2-deficient cardiomyopathy.
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BACKGROUND: The only clinically approved drug that reduces doxorubicin cardiotoxicity is dexrazoxane, but its application is limited due to the risk of secondary malignancies. So, exploring alternative effective molecules to attenuate its cardiotoxicity is crucial. Colchicine is a safe and well-tolerated drug that helps reduce the production of reactive oxygen species. High doses of colchicine have been reported to block the fusion of autophagosomes and lysosomes in cancer cells. However, the impact of colchicine on the autophagy activity within cardiomyocytes remains inadequately elucidated. Recent studies have highlighted the beneficial effects of colchicine on patients with pericarditis, postprocedural atrial fibrillation, and coronary artery disease. It remains ambiguous how colchicine regulates autophagic flux in doxorubicin-induced heart failure. METHODS AND RESULTS: Doxorubicin was administered to establish models of heart failure both in vivo and in vitro. Prior studies have reported that doxorubicin impeded the breakdown of autophagic vacuoles, resulting in damaged mitochondria and the accumulation of reactive oxygen species. Following the administration of a low dose of colchicine (0.1 mg/kg, daily), significant improvements were observed in heart function (left ventricular ejection fraction: doxorubicin group versus treatment group=43.75%±3.614% versus 57.07%±2.968%, P=0.0373). In terms of mechanism, a low dose of colchicine facilitated the degradation of autolysosomes, thereby mitigating doxorubicin-induced cardiotoxicity. CONCLUSIONS: Our research has shown that a low dose of colchicine is pivotal in restoring the autophagy activity, thereby attenuating the cardiotoxicity induced by doxorubicin. Consequently, colchicine emerges as a promising therapeutic candidate to improve doxorubicin cardiotoxicity.
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Autofagia , Cardiotoxicidade , Colchicina , Doxorrubicina , Lisossomos , Miócitos Cardíacos , Colchicina/toxicidade , Colchicina/farmacologia , Doxorrubicina/toxicidade , Cardiotoxicidade/prevenção & controle , Autofagia/efeitos dos fármacos , Lisossomos/efeitos dos fármacos , Lisossomos/metabolismo , Animais , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , Modelos Animais de Doenças , Masculino , Insuficiência Cardíaca/induzido quimicamente , Insuficiência Cardíaca/tratamento farmacológico , Insuficiência Cardíaca/metabolismo , Antibióticos Antineoplásicos/toxicidade , Espécies Reativas de Oxigênio/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Função Ventricular Esquerda/efeitos dos fármacosRESUMO
Hazardous heavy metal-laden coal combustion byproducts exposed to precipitation or surface/groundwater are of environmental concern. This study analyzed fly ash (FA) and desulfurization gypsum (FGD gypsum) samples obtained from 16 coal-fired power plants in Guizhou Province, China. A combination of field and laboratory studies was used to investigate the binding forms of lead (Pb), cadmium (Cd), and chromium (Cr) and their leaching characteristics under natural storage conditions. The results showed that there were significant proportions of residual states of these elements in FA (84-99% for Pb, 83-91% for Cd, and 73-97% for Cr), indicating a lack of migration to other environmental media. FGD gypsum contained high proportions of metals in migratable states, but the environmental risks were low due to their very low concentrations. The release of Pb, Cd, and Cr from FA and FGD gypsum into extracts varied according to pH. This is related to the form of each element in the solid and the series of reactions that occurs during the leaching process. However, aside from Cr in FA, all heavy metals in FA and FGD gypsum samples were present in concentrations below the relevant standards for landfill leachate, indicating very low release rates. The Cr levels (206-273 µg/L) in some of the FA extracts were higher than the limits for water pollution from domestic landfill, indicating that Cr in FA poses a leaching risk. The results of field leachate sampling and indoor simulated rainfall experiments further validated these findings, indicating that the release of Cr from stockpiled coal FA is a cause for concern.
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Metais Pesados , Poluentes Químicos da Água , Cádmio , Sulfato de Cálcio/química , Cromo , Carvão Mineral , Cinza de Carvão/química , Chumbo , Centrais ElétricasRESUMO
In agricultural lands with selenium (Se) deficiency, bioavailability of Se in plants is low. Residents from large-scale agricultural production areas with Se deficiency often suffer from endemic diseases because of consumption of agricultural products lacking in Se. One such area in Northeast China where Keshan disease and Kashin-Beck disease originated, was selected for investigating the geochemistry, influencing factors, and risks of Se in the agroecosystems. Analysis of field samples indicates that the Se deficiency in soil is significantly reduced compared with that of several decades ago, and 62.6% of soils are now Se-sufficient in the southern Songnen Plain. However, Se in crop products remains low due to weak soil-plant transfer, resulting in high risks of Se deficiency related diseases in the rural population of this area. Structural equation modeling, principal component analysis, and other statistical analyses revealed that climate conditions and soil physical and chemical properties are the key factors influencing the spatial distribution of soil Se. Extensive use of agricultural fertilizers may indirectly inhibit the migration of Se from soil to plants. Ensuring sufficient Se contents in agricultural products to meet the minimum daily requirements of residents remains a challenge in Se-deficient areas, especially in the increased agricultural production environment in China.
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Doença de Kashin-Bek , Selênio , China/epidemiologia , Fertilizantes/análise , Humanos , Selênio/análise , SoloRESUMO
Houttuynia cordata Thunb. (HCT) is a common vegetable native to southwest China, and grown for consumption. The results suggested that THg contents in all parts and MeHg in underground parts of HCT in Hg mining areas were much higher than those in non-Hg mining areas. The highest THg and MeHg content of HCT were found in the roots, followed by the other tissues in the sequence: roots > leaves > rhizomes > aboveground stems (THg), and roots > rhizomes > aboveground stems > leaves (MeHg). The average THg bioaccumulation factor (BCF) of HCT root in the Hg mining area and in non-Hg mining areas could reach 1.02 ± 0.71 and 0.99 ± 0.71 respectively, indicating that HCT is a Hg accumulator. And the THg and MeHg contents in all tissues of HCT, including the leaves, were significantly correlated with THg and MeHg content in the soil. Additionally, preferred dietary habits of HCT consumption could directly affect the Hg exposure risk. Consuming the aboveground parts (CAP) of HCT potentially poses a high THg exposure risk and consuming the underground parts (CUP) may lead to a relatively high MeHg exposure risk. Only consuming the rhizomes (OCR) of the underground parts could significantly reduce the exposure risk of THg and to some extent of MeHg. In summary, HCT should not be cultivated near the Hg contaminated sites, such as Hg tailings, as it is associated with a greater risk of Hg exposure and high root Hg levels, and the roots should be removed before consumption to reduce the Hg risk.
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Contaminação de Alimentos/análise , Houttuynia/química , Mercúrio/análise , Verduras/química , China , Humanos , Componentes Aéreos da Planta/química , Raízes de Plantas/química , Solo/químicaRESUMO
Non-ferrous metal smelting is a significant source of anthropogenic heavy metal emission and has led to severe environmental pollution that ultimately threatens the health of local residents. In this study, we determined concentrations of copper (Cu), zinc (Zn), cadmium (Cd) and lead (Pb), as well as Pb isotopic compositions in rice, vegetables and human hair in areas surrounding the Zhuzhou Pb/Zn smelter in Hunan, China and we assessed the health risks associated with rice and vegetable consumption for local residents. Results showed that rice and vegetable samples were significantly contaminated by Cd and Pb. Age and source of rice were important factors for the enrichment of heavy metal concentrations in human hair. The ratios of Pb isotopes in human hair (1.164-1.170 for 206Pb/207Pb and 2.102-2.110 for208Pb/206Pb) were comparable to those in rice (1.162-1.172 for 206Pb/207Pb and 2.098-2.114 for208Pb/206Pb) and were slightly lower than those in vegetables (1.168-1.172 for 206Pb/207Pb and 2.109-2.111 for208Pb/206Pb), indicating that Pb in human hair mainly originated from food ingestion. A non-carcinogenic risk assessment showed that Cd exposure was the dominant health risk for local residents. This study suggested that crops planted surrounding the smelter were seriously contaminated with Cd and human exposure was related to dietary intake.
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Metais Pesados , Oryza , Poluentes do Solo , China , Produtos Agrícolas , Monitoramento Ambiental , Humanos , Chumbo , Metais Pesados/análise , Medição de Risco , Poluentes do Solo/análise , Verduras , Zinco/análiseRESUMO
Disclosing the fate of lead (Pb) and cadmium (Cd) during the cement production process is the key to control their atmospheric emissions, which have not attracted much attention yet. In this study, three precalciner cement plants (CPs) using different raw materials in Guizhou Province in Southwest China were investigated. It showed that the concentrations of Pb and Cd in different raw materials and the associated total metal input of these materials were different among CPs; the behavior of Pb and Cd were almost the same during the clinker production process that there has been no accumulation of these two elements inside the system, and nearly all input of Pb and Cd were discharged by the clinker. Although the temperature of clinkerization was pretty high of 1450 °C, the atmospheric emission ratio of both metals was negligible (<0.006% for Pb and <0.002% for Cd of the total output, respectively); the main reason might be that the two elements were incorporated into the minerals of clinker, either as silicate or sulfate. The long-term environmental impacts of some high Pb-and Cd-laden clinkers and cement need to be monitored and evaluated.
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Antimony (Sb), a priority pollutant listed by the U.S. Environmental Protection Agency (USEPA), can cause adverse effects on human health, with particular impacts on skin, eyes, gastrointestinal tract, and respiratory system. In this study, a database of Sb concentrations in the global atmosphere was developed through a survey of measurements published in more than 600 articles, which was then used to assess the health risks of Sb exposure based on a USEPA assessment model. Most measurements showed Sb concentrations of less than â¼10 ng m-3, but those at several contaminated sites exhibited Sb concentrations of more than 100 ng m-3. For measurements conducted in urban environments, Sb concentrations in the total suspended particles (TSP) and particles of less than 10 (PM10) or 2.5 µm (PM2.5) were the highest in Asia, followed by Europe, South America, and North America. Sb concentrations were generally higher in winter and fall than during other seasons in TSP and PM10 samples. A significant correlation was observed between Sb and As in TSP and PM2.5 on a global scale. Sb was mainly derived from anthropogenic sources, especially traffic emission, industrial emission, and fossil combustion. Hazard quotients (HQ) of Sb in TSP, PM10, and PM2.5 were higher for children than adults because of their lighter body weight, inferior physical resistance, and higher ingestion probability. The global database for atmospheric Sb concentrations demonstrates a relatively low noncarcinogenic risk in most regions. Long-term monitoring is still required to identify the sources and growth potentials of Sb so that effective control policies can be established.
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Characterizing the composition of mercury (Hg) isotopes in the atmospheric emissions of cement plants is critical to understand the global circulation of Hg because large quantities of Hg are released from this source annually. A pre-calciner cement plant in Guizhou Province in Southwest China was selected to investigate the mass dependent fractionation (MDF) and mass independent fractionation (MIF) of Hg in the entire production process and the speciated Hg isotope composition in stack gas. Significant MDF and insignificant MIF were observed in this cement plant. Different raw/correction materials have δ202Hg signals ranging from -1.68 to -2.19. Raw meal is featured with lighter Hg (δ202Hg = -2.83 ± 0.18) as results of Hg circulation and accumulation during the clinker production. Cement products possess negative δ202Hg values (-1.98 ± 0.02) due to the input of light δ202Hg isotopes through additives/retarder limestone, and fly ash and gypsum from coal-fired power plant (CFPPs). Speciated Hg isotopes in the stack gas of the kiln tail and kiln head show no significant differences, and δ202Hg and Δ199Hg in the discharged flue gas averaged at -2.03 ± 0. 31 and -0.03 ± 0.07, respectively, which has negative δ202Hg characteristics with other anthropogenic sources.