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This study explored the mechanism of antimony (Sb) isotopic fractionation during chemical weathering and soil biogeochemical processes, which have important implications for Sb isotopic composition in the hydrosphere. We analyzed the major and trace element contents and Sb isotopic composition along an 8 m deep basalt weathering profile in the Huguangyan area of Guangdong Province, southern China. Mineral adsorption experiments were conducted to determine the mechanism of Sb isotopic fractionation in the weathering profile. The following minerals, α-FeOOH, γ-Fe 2 O 3 , β-MnO 2 , γ-Al 2 O 3 , montmorillonite-K10, and kaolinite-1A, preferentially adsorbed light Sb isotopes, and increased pH may lead to a lighter isotopic composition of adsorbed Sb. The positive values of τ Sb TiO 2 in the upper profile reflect exogenous Sb inputs, such as rainfall and litterfall. Accordingly, Sb isotopic fractionation is controlled by Sb adsorption onto organic matter and Fe (hydr)oxides in surface soil. At a depth of 1.8 m, Sb and other redox-sensitive elements, such as Fe, Mn, Ce, Co, Cr, and Mo, were distinctly enriched. Changes in the redox conditions result in strong Sb isotopic fractionation. In the middle layer (2–4 m), the combined effects of changes in organic matter content, soil pH, and weathering intensity explains the enrichment of light Sb isotopes. The bottom layer of the profile did not receive exogenous Sb and exhibited an Sb isotopic fractionation pattern similar to that of the basaltic bedrock. In the bottom layer, secondary Fe (hydr)oxides (e.g., goethite and hematite) preferentially adsorb the light Sb isotope (121Sb), whereas the heavy Sb isotope (123Sb) is released into the aquatic environment during intensive chemical weathering. [ABSTRACT FROM AUTHOR]

Isotopic compositions of antimony (Sb) in airborne particles could reveal the sources and geochemical processes of Sb. Today, the precise analysis of the Sb isotopic ratio in airborne particles is still challenging due to technical difficulties in the sampling and pretreatment processes. In this study, traditional methods of sampling and pretreatment of Sb in airborne particles were optimized to meet the isotope measurement requirements. Suitable digestion methods were suggested for various membrane filters (MF) of different materials and brands, and the Sb blank values in these membrane filters were compared. The results showed that the Whatman brand quartz microfiber MF had the lowest Sb blank value (1.13 ng cm−2), and could meet the needs of continuous large flow sampling, making it the most ideal MF for sampling Sb in airborne particles for the subsequent measurement of Sb isotope ratios. Synthetic samples of the MF spiked with certified reference materials (CRMs) were digested and tested. Nearly identical ε123Sb values were observed among CRMs, (MF + CRMs), and (MF + CRMs) subtracting the content proportion of MF, which indicated that the isotope fractionation occurred during the pretreatment was negligible, and that the Sb isotopic composition of airborne particulate matter was basically not affected by the Whatman brand quartz microfiber MF. This method has been successfully applied to total suspended particles and fine particulate matter (PM2.5) collected in Guiyang in southwest China. [ABSTRACT FROM AUTHOR]

The genesis of the giant Ag-Cu-Pb-Zn polymetallic mineralization in the northern Lanping basin, Southwest China, remains controversial. To address the sources of metals, a systematic study on Hg isotope compositions was conducted for the Cu-dominated deposit at Baiyangping and the Pb-Zn-dominated deposits at Fulongchang and Liziping. The Cu deposit shows positive Δ199Hg signatures (0.14 ± 0.13‰), in contrast to the Δ199Hg of the Pb-Zn deposits (− 0.09 ± 0.06‰). As positive Δ199Hg values are commonly observed in marine sediments and the Lanping Triassic marine sedimentary rocks show exclusively positive Δ199Hg signals (0.03 ± 0.07‰), the Hg in Cu ores was mainly sourced from the Triassic strata. The negative Δ199Hg signals observed in the Pb-Zn deposits, typical of terrestrial Hg, agree roughly with those of the Jurassic to Paleocene terrestrial sedimentary rocks (− 0.05 ± 0.08 ‰), indicating that the terrestrial strata provided the Hg in Pb-Zn ores. Compared to the source rocks, the Cu deposit shows isotopically lighter Hg enrichments (δ202Hg = − 2.30 ± 0.35‰), possibly resulting from fractionations induced by Hg2+ sorption, organic complexation, and precipitation of Hg-bearing sulfides. The Pb-Zn deposits show comparable or slightly heavier δ202Hg (− 0.56 ± 0.48‰); moreover, δ202Hg values of late-stage sulfides are higher than early-stage δ202Hg values, suggesting that the δ202Hg variation was primarily caused by sulfide precipitation. Thus, Hg isotope data indicate that separate hydrothermal events resulted in Cu and Pb-Zn mineralization. More importantly, this study reveals the great potential of Hg isotopes to discriminate sedimentary sources of metals for low-temperature hydrothermal deposits. [ABSTRACT FROM AUTHOR]

Coal-fired power plants (CFPPs) are an important anthropogenic mercury (Hg) source in China, and it is crucial to understand the environmental impacts of this detrimental element emitted from this source. In the present study, field experiments were conducted for measuring Hg in ambient atmosphere and upland agricultural soils within a radius of 10 km surrounding a large scale coal-fired power plant (1550 MW) in Tangshan, Hebei province. Short-term (20 min) average of gaseous elemental mercury (GEM or Hg0) in ambient air varying from 1.5 to 9.0 ng/m3 and total Hg (THg) in surface agricultural soil (0–20 cm) varying from 9.2 to 43.5 μg/kg at different sites were observed. THg in two soil cores decreased with depth, with concentrations being 2–2.5 times higher in the surface layer than that in the deep layer (50–60 cm), indicating the possibility of the atmospheric input of Hg. Based on the information of the total atmospheric Hg emission since this CFPP's operation in 1970s and the increased THg in nearby soils, it was estimated that about 3.9% discharged Hg has accumulated in the nearby agricultural soils. The low retention rate of the total emitted Hg by soils is a result of high proportion of Hg0 (79.5%) in stack gas emission and potential loss of Hg from soil surface reemission. The positive shifting (~ 0.5‰) of Hg isotopic signature (δ202Hg) from deep soil to surface soil reflected Hg deposition from nearby CFPP emissions that are featured with much heavier Hg isotopic signatures inherited from feed coal (δ202Hg: –0.50‰) and different combustion products (δ202Hg: –0.95 to 3.71‰) compared with that in deep soil layer (δ202Hg: ca –1.50‰). Overall, this study demonstrated that this CFPP has a slight but distinguishable effect on the elevation of ambient GEM and agricultural soil THg in the local environment. [ABSTRACT FROM AUTHOR]

The morphology, trace-element composition and geochronology of 43 zircon grains from two monzogranite samples from the Northeast Xing'an Block, northeastern China, were determined using cathodoluminescence imaging and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). Three morphological subtypes (S3, S8 and S9) are recognized in the zircon grain samples, and subtype S8 is dominant, reflecting a calc-alkaline, moderately aluminous, high-pressure crystallization medium and a crystallization temperature of 700 ± 50 °C. The zircon grains are characterized by oscillatory zoning, relatively high Th/U ratios (0.3–1.0), steep chondrite-normalized rare-earth element patterns, high Hf contents (>9000 ppm), positive Ce (Ce/Ce* = 4.84 to 2914) and negative Eu (Eu/Eu* = 0.24 to 0.90) anomalies, indicating a magmatic source. The 206Pb/238U ages of the two monzogranite samples are 180 ± 1 and 181 ± 1 Ma, respectively, implying an Early Jurassic emplacement age for the intrusion. The disparate geochemical behaviors of Hf, Th, and Nb within the zircons, as well as the U/Yb, Nb/Yb, Th/U, Nb/Hf, Th/Nb, and Hf/Th ratios, suggest a continental-crust source in a compressional-magmatic-arc or orogenic-tectonic setting, and a calc-alkaline parent magma. All of the grains show relatively high Ce4+/Ce3+ ratios, suggesting that they were derived from an oxidized magma, which favors enrichment of Cu-Mo elements in the granite porphyry. [ABSTRACT FROM AUTHOR]

In this paper, we report new whole-rock geochemical and zircon U-Pb data for monzogranites in the NE Xing’an block. These data constrained the petrogenesis of C type (high Sr/Y) adakitic rocks and showed the spatial extent of the influence of the Mongol-Okhostsk ocean tectonic regime and the collision between the Jiamusi Massif and Songliao Terrane. New zircon laser-ablation inductivity coupled plasma mass spectrometry (LA-ICP-MS) U-Pb data indicated that the monzogranites in the studied area were emplaced in the Early Jurassic (~180 Ma). These rocks were characterized by unusally high SiO2 (≥67.49), and Sr (461-759 ppm), but strikingly low Y (4.63-8.06 ppm) and HREE (∑HREE = 3.83-6.49 ppm, Yb = 0.5-0.77 ppm) contents, with therefore high Sr/Y (67.2-119) and (La/Yb)N (29.7-41.5) ratios, showing the geochemical characteristics of C type adakitic granite. The data displayed negligible Eu anomalies (Eu/Eu* = 0.77-1.08), LREE-enriched and pronounced negative Nb and Ta anomalies. The C-type adakites in the studied area were most likely derived from the partial melting of a thickened lower continental curst. The magma source is most likely dominated by amphibolites and garnet amphibolites. In combination with previously-reported data from igneous rocks from the Mesozoic in NE China, we conclude that the Xing’an block was influenced by the Mongol-Okhotsk subduction tectonic system, and experiences compressive settings from the amalgamation of the Jiamusi block in the east of the CAOB. [ABSTRACT FROM AUTHOR]

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, with an average of 115.9 mg kg, 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. [ABSTRACT FROM AUTHOR]

A total of 159 coal samples from different regions, periods and ranks across China were systematically analyzed for antimony (Sb) isotopic composition (ε123Sb), trace element contents and total sulfur content (TS) in this study. Here, we discuss the origin of Sb in coal from different regions of China. Antimony in coal from SW and NE China is primarily of hydrothermal fluid and leachate origins, respectively. In comparison, Sb in northern Chinese coal mainly comes from terrigenous materials and hydrothermal fluid. Antimony in coal from NW China may be influenced by the superposition of hydrothermal activity and leaching solution. Inorganic minerals (e.g., sulfide) and organic matter in coal are the determining factors for Sb enrichment in coal. The Sb isotopic fingerprint of Chinese coal is 2.46 ± 1.01 ε (weighted mean ± 1 SD, ranging from −4.45 to +9.72 ε). Accordingly, the isotopic composition of Sb in coal has great potential not only for researching Sb isotope fractionation in hydrothermal systems but also for tracing Sb release and transport in the supergene eco-environment. Furthermore, the establishment of Sb isotopic fingerprint for coal could largely reduce the uncertainty in the application of Sb isotope methods. [ABSTRACT FROM AUTHOR]

B Retraction Note to b : B Mineralium Deposita (2022) 57:399-415 b https://doi.org/10.1007/s00126-021-01070-3 The Editors-in-Chief have retracted this article because Table 2 contains data used in a previously published article (Liu et al. [1]). All authors agree to this retraction and to the wording of this retraction notice. [Extracted from the article]

Abstract: Agricultural soil pollution is a serious problem that can endanger ecology, food safety, and human health. The study evaluated the accumulation and distribution of major and trace elements in the agricultural soil of the Gannan area in the northwest Songnen-Plain, a very important base of grain production in northeastern China. To identify the concentrations and sources of pollutants and also to assess the soil environmental quality, a total of 2400 topsoil (0–20cm) samples and 10 subsoil (180–200cm) samples were collected. Then 6 major elements (CaO, Fe2O3, K2O, MgO, Na2O, SiO2), 18 trace elements (As, B, Cd, Co, Cr, Cu, F, Hg, I, Mo, Mn, N, Ni, P, Pb, Se, S, and Zn), pH, and Corg (organic carbon) were analyzed. The accumulation of Cd, Cu, Pb, Zn, Hg, and F was apparent in the agricultural soils. Correlation coefficient analysis showed that most major and trace elements, as well as pH and Corg, were significantly positive correlated in agricultural soil. Principal component analysis (PCA) indicated two main anthropogenic sources for trace elements in agricultural topsoil. The first component including B, Cr, Cu, Mg, Ni, and Zn, represented a mixture of atmospheric deposition and livestock manures; whereas the second component, relating to Ca, F, Cd, Hg, Se, and P, suggested the inorganic fertilizers and lime, as well as agrochemicals. Spatial distribution patterns using GIS contour maps and an integrated soil pollution index were established for the selected metal concentrations. In general, the range of RI (the potential ecological risk index) was from 43.6 to 556, with a mean value of 106, indicating low ecological risk in this study area. This study indicated that more attention should be paid to metal pollution of agricultural soil in the rural area to safeguard both soil and food safety. [Copyright &y& Elsevier]

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. [Display omitted] • The Hg content of green tea in China ranged from 1.8 to 102.9 µg/kg. • Green tea Hg content could be control by adjusting the harvest time. • Leaching time, water temperature, and solid-liquid ratio affect the Hg leaching ratios from green tea. • Hg expose risk from green tea was low for most cases. [ABSTRACT FROM AUTHOR]

Abstract: A series of representative street dust samples were collected from a heavily industrialized city, Zhuzhou, in central China, with the aim to investigate the spatial distribution and pollution status of 17 trace metal/metalloid elements. Concentrations of twelve elements (Pb, Zn, Cu, Cd, Hg, As, Sb, In, Bi, Tl, Ag and Ga) were distinctly amplified by atmospheric deposition resulting from a large scale Pb/Zn smelter located in the northwest fringe of the city, and followed a declining trend towards the city center. Three metals (W, Mo and Co) were enriched in samples very close to a hard alloy manufacturing plant, while Ni and Cr appeared to derive predominantly from natural sources. Other industries and traffic had neglectable effects on the accumulation of observed elements. Cd, In, Zn, Ag and Pb were the five metal/metalloids with highest pollution levels and the northwestern part of city is especially affected by heavy metal pollution. [Copyright &y& Elsevier]

• THg and Hg isotope composition in reservoir sediments were determined. • The deeper sediment layer corresponded to the reclaiming of wetland into farmland. • The upper sediment revealed the soil erosion inputs by agriculture soil. • Human disturbance induced in fluctuations of THg and Hg isotope in local environment. Northeast China possess large areas of agricultural farmlands that were reclaimed from earlier marsh wetlands in the past several decades, while the response of trace element like mercury (Hg) in this process were not fully understood. In the present study, total mercury (THg) and Hg isotope composition were determined in reservoir sediment cores of a reservoir, agricultural soils and forest soils in Northeast China to reveal the possible impacts of agricultural activities on Hg geochemistry in the reservoir. The more negative δ202Hg (↓0.35‰), increased concentrations of THg (↑22.4 ng g−1), and higher organic matter (OM) (↑10%) in the deeper than the upper layer sediments indicate noticeable Hg input about 50–60 years ago, which is coincident with the grand reclamation of marsh wetland in the study area. The gradual decrease in THg content and the increase of δ202Hg value in the upper sediment layer reflect the weakened reclamation and thus less Hg input in the later decades. Using a triple mixing model, it is estimated that more than half of Hg in this reservoir sediment was originated from the reclamation of marsh wetlands into farmlands in the earlier stage and soil erosion in the later period. The study demonstrated that Hg isotope signatures in reservoir sediment core can reflect the landscape changes, such as reclamation. [ABSTRACT FROM AUTHOR]

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. Image 1 • The distribution of metals was controlled by parent materials, traffic emissions, and coal combustion. • Lead, As, and Sb are sensitive indicators of anthropogenic activities. • Traffic emission is still the most important anthropogenic source of Pb in Haikou. [ABSTRACT FROM AUTHOR]

Background: Previous studies have revealed that nearly 15-20% of selected high-risk T1-2N0 breast cancers developed LRR after mastectomy. This study is aim to indentify the risk factors of locoregional recurrence (LRR) in patients with pathologic T1-2N0 breast cancer after mastectomy in a real-world and distinguish individuals who warrant postmastectomy radiotherapy (PMRT).Methods: Female patients treated from 1999 to 2014 in National Cancer Center of China were retrospectively reviewed. A competing risk model was developed to estimate the cumulative incidence of LRR with death treated as a competing event.Results: A total of 4841 patients were eligible. All underwent mastectomy plus axillary nodes dissection or sentinel node biopsy without PMRT. With a median follow-up of 56.4 months (range, 1-222 months), the 5-year LRR rate was 3.9%.Besides treatment era, age ≤ 40 years old (p < 0.001, hazard ratio [HR] = 2.262), tumor located in inner quadrant (p < 0.001, HR = 2.236), T2 stage (p = 0.020, HR = 1.419), and negative expressions of estrogen receptor (ER) and progesterone receptor (PR) (p = 0.032, HR = 1.485), were patients-related independent risk factors for LRR. The 5-year LRR rates were 1.7, 3.5, and 15.0% for patients with zero, 1-2, and 3-4 risk factors (p < 0.001).Conclusions: Risk Stratification based on age, T stage, ER/PR status and tumor location can stratify patients with pT1-2 N0 breast cancer into subgroups with different risk of LRR. PMRT might be suggested for patients with 3-4 risk factors. [ABSTRACT FROM AUTHOR]

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 (F C1 , r2 = 0.796, p < 0.01) and the elemental Hg that is bound to the crystalline oxides (F C3 , r2 = 0.711, p < 0.01), and negatively correlated with Hg that is bound to humic and fulvic complexes (F C2 , - 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. Image 1 • Historical Hg mining activities greatly increased Hg content in Houttuynia cordata Thunb. (HCT). • Houttuynia cordata Thunb. (HCT) may count as high as 61% of total vegetable Hg intake of in a mining area of southwest China. • Hg in soil bound to humic and fulvic complexes negatively correlated with Hg in HCT. • Children's risk of Hg exposure though HCT intake are much higher than that of adult. • December 27, 2019. [ABSTRACT FROM AUTHOR]

• Average mercury isotopic signature in Chinese street dust was −0.61 ± 0.92 ‰ for δ202Hg and −0.03 ± 0.08 ‰ for Δ199Hg. • E-waste dust featuring positive δ202Hg (0.36 ± 0.63‰) and near-zero Δ199Hg (0.10 ± 0.02 ‰) was reported for the first time. • Mercury mining/smelting, nonferrous metal smelting, and coal-based industries resulted in hotspots of Hg contamination. • Street dust is an important THg exposure source for children in urban environments. Spatial distribution and isotope signature of mercury (Hg) in street dusts across China were investigated by collecting dust samples from 14 cities and reviewing previously published data from an additional 46 cities. Potential sources of street dust and the associated health risks to humans were also assessed. The total Hg (THg) concentrations in street dust ranged from 0.020–39.1 mg kg−1 with an average of 0.433 ± 0.185 mg kg−1 in the 60 cities. Street dust samples collected from 14 cities were characterized by slightly negative δ202Hg (−0.61 ± 0.92‰) and near-zero Δ199Hg (−0.03 ± 0.08‰) values, and coal combustion and industrial activities were estimated to be the major sources of Hg in street dust. The estimated average probable daily intake (PDI) of THg from street dust exposure for adults and children (1.36E–03 and 1.27E–02 μg d−1 kg−1, respectively) were comparable to their respective exposures via rice consumption in China. Children being exposed to THg in dust is a major concern in mercury mining areas (e.g., Wangshan and Xunyang), and may also be a concern in cities with major coal-based industries and nonferrous metal smelting. Results from this study suggest that exposure to street dust is not a primary MeHg exposure pathway in China. [ABSTRACT FROM AUTHOR]

Trace elements and Hg isotopic composition were investigated in mineralized rocks, barren rocks, and mineral soils in the Xianfeng prospect, a shallow buried epithermal gold deposit in northeastern China, to understand whether this deposit has left a diagnostic geochemical fingerprint to its weathered horizon. All the rocks and soils display congruent patterns for immobile elements (large ion lithophile elements, high field strength elements, and rare earth elements), which reflect the subduction-related tectonic setting. Both mineralized rocks and soils showed common enrichment of elemental suite As–Ag–Sb–Hg, suggesting that the Xianfeng gold deposit has released these elements into its weathered horizon. Similar mercury isotopic composition was observed between mineralized rocks (δ202Hg: −0.21 ± 0.70‰; Δ199Hg: −0.02 ± 0.12‰; 2SD) and barren rocks (δ202Hg: −0.46 ± 0.48‰; Δ199Hg: 0.00 ± 0.10‰; 2SD), suggesting that mercury in the Xianfeng deposit is mainly derived from the magmatic rocks. Mineralized soils (δ202Hg: −0.44 ± 0.60‰; −0.03 ± 0.14‰; 2SD) and barren soils (δ202Hg: −0.54 ± 0.68‰; Δ199Hg: −0.05 ± 0.14‰; 2SD) displayed congruent Hg isotopic signals to the underlying rocks, suggesting limited Hg isotope fractionation during the release of Hg from ore deposit to soils via weathering. This study reveals evidence of a simple and direct geochemical link between this shallow buried hydrothermal deposit and its weathered horizon, and highlights that the weathering of shallow-buried hydrothermal gold deposits can release a substantial amount of heavy metals (e.g. Hg, As and Sb) to surface soil. Image 1 • Paired rocks and soils display congruent patterns for immobile elements. • Soils display congruent Hg isotopic signals to the underlying rocks. • Mineralized rocks and soils showed common enrichment of elemental suite As–Ag–Sb–Hg. • Limited Hg isotope fractionation occurs during the release of Hg from ore deposit to soils via weathering. [ABSTRACT FROM AUTHOR]

The geochemical characteristics of atmospheric deposition can help trace the origin and assess the impacts of pollutants. Northeast China has always been a region seriously affected by sandstorms. This study aims to explain the potential source of sandstorms in Gannan County, Heilongjiang Provence, by collecting dust and analyzing geochemistry in one year where there is no significant industrial or anthropogenic pollution. Input fluxes of deposition show that Zn and Mn were more prevalent (36.7 g·hm−2·a−1 and 77.93 g·hm−2·a−1, respectively) than other elements. The geochemical composition of atmospheric deposition samples from 17 collection points in Gannan County were determined with regard to 20 elements including nine heavy metals, two metalloids, three nonmetallic elements, a transition metal, and five other major elements. The discriminate function (DF) and chemical index of alteration (CIA) indices indicate that Gannan County (agricultural production area) and Harbin (densely inhabited district) have similar geochemical characteristics of dry deposition. The integration of Na/Al and Ca/Mg ratios with an air mass back-trajectories model shows effects from Russian dust sources (36.6%) and from the northwest desert of China (13.3%). The results will assist in developing strategies for reducing dry deposition pollution inputs to agricultural soils in the area and will effectively target policies to protect soils from long-term contaminant accumulation. [ABSTRACT FROM AUTHOR]

Coal-fired power plants (CFPPs) are an important anthropogenic emission source of atmospheric mercury (Hg). Understanding the co-benefits of conventional air pollution control devices (APCDs) on Hg reduction is crucial for reducing Hg emission from this source. In this study, atmospheric Hg emission from a pulverized coal (PC) utility boiler in North China was investigated along the emission control stage of selective catalytic reduction (SCR), electrostatic precipitator (ESP) and fabric filter (FF) and lime stone-gypsum wet flue gas desulfurization (WFGD). Historical atmospheric Hg emission from this CFPP with total 1550 MW capacity since its operation in 1976 was estimated based on the implementation of different configurations of APCDs. The results showed that a combination of SCR + ESP-FF + WFGD leads to a co-beneficial Hg control of 96%, with the in-stack Hg concentration (0.87 μg m−3) much lower than the Chinese national standard for CFPPs (30 μg m−3), and the stack Hg speciation (Hg0:Hg2+:Hgp) was in 86%:13%:1%. Mass balance analysis indicates that Hg from the input of feed coal and limestone was mainly ended up in fly ash (89%), followed by gypsum (5%), stack gas (5%) and bottom ash (1%), respectively. During the past 42 years of operation (1976–2017), the total air Hg emission from this CFPP summed to 17.62 tonnes, in which Hg0 make up 14.02 tonnes (79.5%), Hg2+ make up 3.15 tonnes (17.9%) and Hgp 0.45 tonne (2.6%). Although the speciation of emitted Hg into the atmosphere changed with respect to the configuration of APCDs, Hg0 was the most dominated emission species (64–98%) for all time. Nearly 90% of total Hg emissions occurred in the first three decades when venturi scrubber (VS) and ESP were the primary APCDs. The installation of WFGD and SCR substantially decreased the Hg emission factors by 17 times compared to the peak values during 1998–2004. This study demonstrates the combination of SCR + ESP-FF + WFGD as a best available technology (BAT) for Hg control in CFPPs in China. Image 1 • Installation of WFGD, ESP-FF and SCR dramatically reduced the Hg emission factors. • >95% Hg removal from CFPP flue gases was accomplished with SCR + ESP-FF + WFGD. • Captured Hg remained mainly in ESP-FF fly ash and followed by WFGD gypsum. • 17.6 tonnes of Hg was cumulatively released into ambient air from 1976 to 2017. • Hg0:Hg2+:Hgp in a ratio of 79.5%:17.9%:2.6% for emitted Hg into atmosphere in the past four decades. [ABSTRACT FROM AUTHOR]

Abstract Rice samples were collected at 560 sites in 15 provinces across China in areas without known point mercury (Hg) sources. Total mercury (THg) and methylmercury (MeHg) concentrations were analyzed in these rice samples for risk assessment. Relatively low THg and MeHg concentrations were found in the majority of the white rice samples with an overall mean of 4.74 (1.06–22.7) μg kg−1 and 0.682 (0.03–8.71) μg kg−1, respectively. The means (range of) THg concentration of rice in each geographical region were 5.23 (1.07–19.5) μg kg−1, 5.14 (1.06–17.2) μg kg−1, 4.45 (1.41–17.2) μg kg−1, 4.20 (1.48–19.4) μg kg−1, 3.49 (1.49–10.7) μg kg−1, and 4.53 (1.30–19.4) μg kg−1 in east, centre, south, southwest, northwest and northeast, China, respectively, and the corresponding values for MeHg concentrations were 0.898 (0.127–8.35) μg kg−1, 0.603 (0.207–2.48) μg kg−1, 0.516 (0.032–1.50) μg kg−1, 0.615 (0.050–5.03) μg kg−1, 0.704 (0.148–2.41) μg kg−1 and 0.565 (0.035–8.71) μg kg−1, respectively. Hg contents in rice across China were found to be at background levels. Both the probable daily intakes (PDIs) of inorganic Hg (IHg) and MeHg from rice consumption showed low risks for general population in the investigated regions. Graphical abstract Unlabelled Image Highlights • A total of 560 rice samples were collected in 15 provinces across China. • Relatively low THg (4.74 μg kg−1) and MeHg concentrations (0.682 μg kg−1) were found in rice samples. • Rice consumption showed low risks for general population in China. [ABSTRACT FROM AUTHOR]

Mercury isotopes display both mass-dependent and mass-independent fractionation and allow the tracing of pathways and storage of surface-derived Hg in the lithosphere. While the subduction-related orogenic recycling of Hg from marine reservoirs into hydrothermal systems in continental arc settings has been documented recently, the source of Hg in intracontinental hydrothermal systems remains unclear. We measured Hg isotopes in two intracontinental anorogenic/postorogenic Late Mesozoic hydrothermal gold deposits in the South China craton and the Central Asian orogenic belt of northern China, respectively. The ore and sulfide samples from the studied systems have positive δ 202 Hg (0.70 ± 0.39‰, 1SD, n = 49) and negative Δ 199 Hg values (−0.12 ± 0.05‰, 1SD, n = 49). These values are different from their country rocks and regional geological environment (volcanic arc granites, marine sedimentary rocks) which have positive Δ 199 Hg values, but similar to that of their Precambrian supracrustal basement rocks of largely non-marine continental materials. We conclude that Hg in the intracontinental hydrothermal systems was leached from basement rocks by upper crustal basinal fluid circulation driven by regional heat flow, likely due to lithospheric thinning and upwelling of the asthenosphere in the Late Mesozoic. The intracontinental hydrothermal systems and their continental sources with positive δ 202 Hg and negative Δ 199 Hg values are complementary to volcanic-arc and marine sedimentary rocks with opposite δ 202 Hg - Δ 199 Hg compositions. The distinct Hg isotopic features of hydrothermal systems in different tectonic settings, in particular the indelible Δ 199 Hg signature, allow the tracing of large-scale material cycling in the Earth. • Hydrothermal systems in arc and intracontinental settings show opposite Δ 199 Hg. • Intracontinental systems have negative Δ 199 Hg reflecting a terrestrial Hg source. • Mercury isotope can be a tracer of Hg cycling in hydrothermal systems. [ABSTRACT FROM AUTHOR]

• Hg and Cu peaks associated with organic matter drawdown immediately before the end of the Marinoan glaciation. • The lack of Δ199Hg and δ202Hg variations from background values argues against enhanced volcanism contributed to observed Hg peaks. • Upwelling and oceanic oxidation contributed to the negative shift of δ202Hg in the cap dolomite. The Cryogenian-Ediacaran transition represents a pivotal geological period in the evolution of global climate, ocean chemistry, and early organisms. The transition is concurrent with the change from Marinoan glacial deposits to overlying cap carbonate/dolomite, which is followed by the appearance of novel animal and algae fossils. Unusual carbon cycling during the deposition of cap carbonate/dolomite is recorded by prominent negative carbonate carbon isotope (δ13C carb) anomalies. The mechanisms which drove melting of the Marinoan icesheets remain uncertain. To explore the cause of this dramatic climate warming and its effect on oceanic biogeochemical cycles, we measured Hg concentrations and isotopes, along with major and trace elements, of the sedimentary succession across the Cryogenian-Ediacaran boundary at the Jiulongwan and Huajipo sections, South China. Hg concentrations show spikes with a ∼ 2 times increase at the top of the Marinoan Nantuo Formation at both sections, which are likely associated with organic matter drawdown rather than enhanced volcanism as indicated by increased TOC contents and similar Hg isotopic signature as those of background Hg deposition. A conspicuous negative shift in δ202Hg along with a positive shift in Δ199Hg are observed in the cap dolomite of the Doushantuo Formation at both sections, which are ascribed to contribution of Hg from anoxic deep water and Hg associated with dissolved organic carbon (Hg-DOC), due to upwelling and oceanic oxygenation after deglaciation. Our Hg data argue against a sudden large igneous province (LIP) event causing Marinoan deglaciation. Results also indicate enhanced upwelling and oceanic oxygenation event during the Cryogenian to Ediacaran transition. [ABSTRACT FROM AUTHOR]

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 Hg 2 Cl 2) 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. [Display omitted] • Mercury was extremely enriched during the clinker production process. • Carbide slag is a high-mercury-laden solid waste that provided the highest mercury input. • Atmospheric emissions of mercury were higher than at other cement plants. • Kiln tail dust poses a considerable environmental risk. [ABSTRACT FROM AUTHOR]

Abstract: The spatial distributions of contaminant metals (Hg, Pb, Zn, Cd, Cu) and a metalloid (As) in vegetable plots and paddy fields located near a large scale Pb/Zn smelter in Hunan province, China, were investigated. Soil located 4km from the smelter was severely contaminated, with maximum concentrations of Hg, Pb, Zn, Cd, Cu and As as high as 2.89, 1200, 3350, 41.1, 157 and 93mgkg−1, respectively. Concentrations of soil metal and As decreased with distance in the dominant wind direction. Single-factor assessment indicated pollution levels of Hg, Pb, Zn and Cd were most severe, while pollution levels for Cu and As were less severe. Results from a potential ecological risk assessment indicated high risk associated with the soil within a 4km radius, with the contribution for each contaminant calculated as follows: Cd (70.0%), Hg (19.4%), Pb (4.8%), As (3.0%), Cu (1.7%) and Zn (1.1%). The forest soil in the nearby city park was also affected by the atmospheric depositions from smelting activities. Soil profiles demonstrated the pollutants were mostly accumulated in the upper 20cm layer. Contamination of the topsoil with Hg, Pb, Zn, Cd, Cu and As indicated remediation should be considered. [ABSTRACT FROM AUTHOR]

The early Cambrian was an important interval in Earth history, marked by significant evolution of both life and the marine environments it inhabited. While enhanced hydrothermal activity has been proposed as a trigger for ecosystem perturbations in the early Cambrian, it remains unclear how intense and how long such perturbations may have been. To address this, we examined mercury (Hg) concentrations and mercury isotopes, as well as major and trace elements, of organic-rich black shales of the lower Cambrian Niutitang Formation, in the Tongren area of Guizhou Province, South China. Our data show that Hg in these sediments is hosted dominantly by organic matter. Elevated raw and normalized Hg contents provide direct evidence of intense hydrothermal activity during the early Cambrian in South China. We suggest that high metal flux (e.g., Mo, U, and Ba) into the seawater occurred through this intense submarine volcanism, altering seawater compositions. Intense hydrothermal activity was likely a significant trigger of environmental and biological evolution during the early Cambrian in South China. • Hg concentrations and isotope evidence intense early Cambrian hydrothermal activity in Tongren area, South China. • A larger amount of elements was released to the seawater from hydrothermal sources. • Local hydrothermal activity plays significant role to the organic matter enrichments. [ABSTRACT FROM AUTHOR]

Residential coal combustion (RCC) is a major source of atmospheric mercury (Hg) in rural areas of China, but little is known about the isotope signatures of Hg from this source. In the present study, the isotope compositions of speciated Hg (Hg0, Hg2+, and Hgp) in flue gas emitted from RCC were investigated in two important coal-producing areas (Xingren (XR) and Jinsha (JS)) of Guizhou Province, Southwest China. The total Hg concentration in discharged flue gas is in the range of 1.80–9.65 μg/m3 at the two sites, and the emission ratio reaches 99.87%. Isotope signatures of total Hg in flue gas are similar to those of Hg in feed coal, with near-zero Δ199Hg and negative δ202Hg (−1.47‰ for XR and −3.00‰ for JS) in discharged flue gas. Such isotope signatures are very different from those of Hg emissions from modern coal-fired power plants with much higher δ202Hg signals. Negative shifts from Hg0 to Hg2+ in flue gas for δ202Hg (−0.94‰) and Δ199Hg (−0.51‰) were observed, suggesting that both mass-dependent fractionation and mass-independent fractionation occurred during RCC. The nuclear volume effect produced by chlorine oxidation of Hg0 to Hg2+ may play an important role in the observed mass-independent fractionation in Hg2+. Without any air pollution control devices, RCC potentially increases the atmospheric Hg levels and has a negative-shifting impact on the δ202Hg of atmospheric Hg. Image 1 • Isotope signature of total Hg is consistent between flue gas and feed coal • Obvious MDF occurred among different Hg species in the flue gas • Significant MIF is observed for Hg2+ due to the oxidation of Hg0 • RCC is an important Hg source and potentially impacts atmospheric Hg isotope composition [ABSTRACT FROM AUTHOR]

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., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Indigenous zinc smelting (IZS) is a backward technique that releases a great deal of heavy metal(loid)s into the environment. However, the contamination of heavy metal(loid)s in ground dust and the associated health risks in such areas are poorly known. In this study, a former IZS area in Guizhou, China, was surveyed during 2008-2018 with 15 elements (Ag, As, Bi, Cd, Co, Cr, Cu, Hg, In, Ni, Pb, Sb, Sn, Tl, Zn) being analyzed. The results indicate that most elements (e.g., Ag, As, Cd, Cu, Pb, Sb, Sn, Zn) in ground dust decreased significantly after the cessation of the IZS in 2006; nevertheless, some elements still remained at relatively high levels in 2018, e.g., Pb (average: 762 ± 647 mg/kg), Zn (average: 1287 ± 753 mg/kg), Cd (average: 7.76 ± 5.06 mg/kg), and As (average: 41.9 ± 34.8 mg/kg), indicating they might come from the local contaminated soils, slag residues and smelting potteries. In terms of the impacts on human health, children have both higher non-carcinogenic and carcinogenic risks than that of adults, with the latter subpopulation having a lower risk than the threshold values. Pb and As were the two elements with the highest non-carcinogenic risk for children, the hazard index of local children was still higher than the threshold of 1 (e.g., 1.43 for As, 2.09 for Pb) in 2018. The carcinogenic risk of As exposure to children dropped more than two times to 6.42 × 10 -7 in 2018, which falls below the tolerable range (10 -6 -10 -4 ). This study revealed that although the concentration of heavy metal(loid)s in ground dust and linked health risk in the IZS area has reduced dramatically after the cessation of IZS, continued removal of slag residues and smelting potteries is necessary for further decreasing the human health risk.