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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]

• The health risk assessment of trace metals in Chinese resident diet was conducted. • Sn are more likely to be enriched in terrestrial and aquatic animals. • Terrestrial plant origin foods contributed more to the EDIs of trace metals. • Diverse trophic transfer behaviors were observed in terrestrial and aquatic foods. Large-scale metal contamination across the food web is an intractable problem due to increasing pollutant emissions, atmospheric transport, and dry and wet deposition of elements. The present study focus on several trace metals that are rarely studied but have special toxicity, including tin (Sn), antimony (Sb), gold (Au), hafnium (Hf), palladium (Pd), platinum (Pt), ruthenium (Ru), tellurium (Te) and iridium (Ir). We investigated trace metals residues and distribution characteristics, and further evaluated the potential health risks from major daily food intakes in 33 cities in China. Sn, Sb, Ir, Hf, and Au were frequently detected in food samples with the concentrations ranged from ND (not detected) to 24.78 µg/kg ww (wet weight). Eggs exhibited the highest residual level of all detected metals (13.70 ± 14.70 µg/kg ww in sum), while the lowest concentrations were observed in vegetables (0.53 ± 0.17 µg/kg ww in sum). Sn accounting for more than 50% of the total trace metals concentration in both terrestrial and aquatic animal origin foods. In terrestrial plant origin foods, Sn and Ir were the most abundant elements. Hf and Au were the most abundant elements in egg samples. In addition, Sb and Ir showed a clear trophic dilution effect in terrestrial environments, while in aquatic ecosystems, Sn, Hf, and Au exhibited obvious trophic amplification effects. The calculated average estimated daily intake (EDI) via food consumption in five regions of China was 0.09 µg/(kg·day), implying the health risk of aforementioned elements was acceptable. Graphical Abstract. [Display omitted]. [ABSTRACT FROM AUTHOR]

Pyrite, the most common sulfide mineral, is a ubiquitous component of many hydrothermal gold deposits. Geochemical patterns within the refractory pyrite structure represent a valuable repository of information that can help constrain the sources of ore-forming materials, and the evolution of ore-forming processes over time. However, there are still a lot of debates on the mechanisms of physico-chemical processes in ore-forming fluid controlling trace element and sulfur isotope distributions in pyrite during growth. In our manuscript, we use cutting-edge complementary microanalytical methods to understand the origin and evolution of zoned gold-bearing pyrite in samples from the largest gold deposit in the Ailaoshan gold belt, SW China, Zhenyuan (exceeding 100t Au, average grade: 5.3 g/t). Pyrite, arsenopyrite, chalcopyrite, and stibnite are the most abundant sulfide minerals in most orebodies. Of these, pyrite is dominant and is also the most important host for gold. Two types of pyrite can be clearly distinguished: framboidal pyrite and hydrothermal pyrite. Gold is most commonly hosted by hydrothermal pyrite. Framboidal pyrite, mainly hosted by carbonaceous slate, hosts negligible Au, and features low δ34S values ranging from − 35.0 (± 0.9) to − 25.6 (± 1.0)‰. Hydrothermal pyrite is characterized by complex intra-grain zoned textures with alternating As-rich and As-poor bands readily recognizable on backscattered electron images. Scanning electron microscopy and trace-element analyses show that both visible and invisible gold occur only in the As-rich bands. Compared to the As-poor bands (72.1% of Au concentration data < 1.96 ppm, n = 43), the As-rich bands are characterized by far higher concentrations of Au (up to 1420 ppm), Cu, Ag, Sb, and Tl, but lower concentrations of Co and Ni. In-situ sulfur isotope analysis indicates that the δ34S values of As-rich zones range from − 7.3 (± 0.6) to 2.9 (± 0.6)‰ and are similar to those of As-poor zones (from − 6.9 (± 0.7) to 2.8 (± 0.6)‰), but distinct from the framboidal pyrite. Combined with published fluid inclusion data and a probable age for the magmatic event associated with mineralization, these data suggest that magmatic–hydrothermal fluids contributed most ore-forming materials and that periodic boiling led to formation of the rhythmic As-rich and As-poor bands in pyrite. Our data for pyrite constrain the evolution of ore-forming processes and provide new insights into the formation of zoned pyrite, with the conclusions having broad implications for analogous hydrothermal gold deposits worldwide. [ABSTRACT FROM AUTHOR]

The Gongguan deposit in southern Qinling district, central China, is characterized by a Hg and Sb metal association, with proven reserves of 7,543 t Hg and 17,100 t Sb. The Hg-Sb mineralized veins are primarily hosted by local Lower Devonian dolomite. Three primary paragenetic stages have been identified, including (I) pyrite-dolomite-quartz, (II) stibnite-cinnabar-quartz-calcite and (III) post-ore calcite. Dominant mercury and antimony mineralization occurred in stage II. Fluid inclusion microthermometry of quartz and calcite reveal that the Hg-Sb mineralization is associated with a low temperature (142° to 240 °C) and low salinity (< 8.6 wt% NaCl equivalent) fluid, belonging to a H2O-NaCl ± CO2 system. The H–O isotope compositions (δDH2O = −84 to −63‰, δ18OH2O = 1.3 to 12.7‰) of the hydrothermal fluid suggest a mixture of metamorphic fluid and meteoric water. In situ sulfur isotope results of cinnabar (δ34S = 3.4 to 14.5‰), stibnite (δ34S = 4.9 to 10.5‰) and pyrite (δ34S = 3.8 to 5.4‰) indicate sulfur sources from decomposition of diagenetic pyrite and/or the thermochemical sulfate reduction in local sedimentary rocks. In situ obtained 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb ratios (18.006 to 18.362, 15.445 to 15.610 and 37.871 to 38.288, respectively) of stibnite and pyrite substantially differ from those for the regional Carlin Au-Sb and SEDEX Pb–Zn ore deposits. The lead isotope results indicate that the underlying Paleozoic (Silurian to Cambrian) strata and Precambrian metamorphic basement supplied substantial metals for the studied Hg-Sb deposit, whereas the host Devonian carbonates did not contribute significant metals. In summary, we propose that fluid mixing between metamorphic fluid and meteoric water was the main cause for carbonate-hosted Hg-Sb deposition at Gongguan, which reduced the stibnite solubility, oxidized mercury (Hg0 to Hg2+), favoring the process of dedolomitization. [ABSTRACT FROM AUTHOR]

To systematically study the environmental problems of heavy metal pollution in soils caused by antimony (Sb) smeltery in central and southern China, the pollution levels, sources and risks of heavy metals were explored based on the GIS, pollution indices, multivariate statistical methods combined with positive matrix factorization (PMF) model, and risk assessment model. The results showed the average contents of Hg, Pb, Cd, Cr, As, and Sb in soils were 0.06, 47.77, 2.88, 53.12, 21.22 and 20.53 mg/kg, respectively. Except for Hg and Cr, the contents of other metals all exceeded the background values of Hunan Mountain soil (BV). Spatial distribution of heavy metal contents and pollution indices (Igeo, PLI, and RI) indicated that above 50% of the studied area were polluted moderately by Cd and Sb, and 77% of sampling sites were under a severe ecological risk level. Multivariate statistics and PMF analysis suggested that Cd (76.9%) and As (57.7%) were mainly from agricultural activities, followed by Sb smelting (12.7% for Cd and 25% for As). The atmosphere deposition of transportation and industrial activities, antimony smelting and nature origin respectively contributed 40.6%, 20.5% and 30.7% of Hg in soils. Sb (73.9%) and Pb (54.5%) were from the Sb smelting, followed by the high geological background (35.6% for Pb and 25% for Sb). Cr (69.7%) was natural origin, but agricultural activities had 21.6% of contribution to its accumulation in soils. Significantly, the values of non-carcinogenic risk (HI) for children under three exposure pathways in different soil depths was bigger than 1 and exceeded the "acceptable level" of risk, and the total carcinogenic risks (TCR) for adults and children were exceeded 1 × 10–4 with an unacceptable carcinogenic risk for human body. Oral ingestion of As was the remarkable characteristic of risk, which should be paid attention to. [ABSTRACT FROM AUTHOR]

To explore the feasibility of reusing solid waste to stabilize high-content arsenic (As) and antimony (Sb) tailings, red mud, fly ash, dried sludge, ferrous sulfate (FeSO4), and rice husk ash (RHA) were used as the stabilizer to stabilize the Sb tailings in Qing Long and Du Shan. The combined treatment with 5% red mud, 10% fly ash, 5% dried sludge, 1% FeSO4, and 1% rice husk ash had the best stabilization effects on As and Sb, the leaching concentrations of As and Sb decreased considerably under neutral conditions, this indicates that the leaching behavior of As and Sb is controlled by the alkaline and acid-retarding capacity of the materials. In addition, the leaching of heavy metals decreases with the formation of (C-S-H) and calcite (CaCO3), indicating that heavy metals exist in the form of metal hydration or hydroxide and precipitate on the surface of calcium silicate hydrate (C-S-H) and calcite particles. Leaching of heavy metals in stabilized materials can be considered as a pH-dependent and control process of stabilization products. [ABSTRACT FROM AUTHOR]

Metal smelting have brought severe metal(loid)s contamination to the soil. Spatial distribution and pollution source analysis for soil metal(loid)s in an abandoned lead/zinc smelter were studied. The results showed that soil was contaminated heavily with metal(loid)s. The mean of lead (Pb), arsenic (As), cadmium (Cd), mercury (Hg) and antimony (Sb) content in topsoil is 9.7, 8.2, 5.0, 2.3, and 1.2 times higher than the risk screening value for soil contamination of development land of China (GB36600-2018), respectively. Cd is mainly enriched in the 0–6 m depth of site soil while As and Pb mainly deposited in the 0–4 m layer. The spatial distribution of soil metal(loid)s is significantly correlated with the pollution source in the different functional areas of smelter. As, Hg, Sb, Pb and copper (Cu) were mainly distributed in pyrometallurgical area, while Cd, thallium (Tl) and zinc (Zn) was mainly existed in both hydrometallurgical area and raw material storage area. Soil metal(loid)s pollution sources in the abandoned smelter are mainly contributed to the anthropogenic sources, accounting for 84.5%. Specifically, Pb, Tl, As, Hg, Sb and Cu mainly from atmospheric deposition (55.9%), Cd and Zn mainly from surface runoff (28.6%), While nickel (Ni) mainly comes from parent material (15.5%). The results clarified the spatial distribution and their sources in different functional areas of the smelter, providing a new thought for the risk prevention and control of metal(loid)s in polluted site soil. [Display omitted] [ABSTRACT FROM AUTHOR]

The process and mechanism of gold mineralization are frontier issues. The Dunbasitao deposit is the most important gold deposit discovered along the Armantai suture zone, East Junggar, NW China, which indicates the potential for future ore exploration in this area. Orebodies are mainly hosted in Lower Carboniferous Jiangbasitao Formation volcano-sedimentary rocks, and the ores are characterized by multistage pyrites. Based on microscopy and backscattered electron imaging studies, pyrites are classified into five types: the pre-ore framboidal/colloidal Py0; the early-stage coarse-grained, cubic, and homogeneous Py1; and the middle-stage fine-grained, cubic/pyritohedron Py2 that includes Py2a (core), Py2b (mantle), and Py2c (rim). The results of the EPMA and in situ LA-ICP-MS analyses show that trace elements of pyrite mainly occur in two forms: solid solutions and invisible or visible inclusions. Mn, Co, Ni, and As enter the pyrite lattice, whereas Ti occurs as mineral inclusions, and Au, Cu, Zn, Sb, and Pb can occur in both forms. Au and As show a positive linear relationship with r = 0.850. Py2b has much higher Au contents (20.1 to 201 ppm) than other pyrite types (Py0: 0.01 to 0.36 ppm; Py1: 0.01 to 0.02 ppm; Py2a: 0.31 to 2.48 ppm; and Py2c: 0.18 to 18.0 ppm). The Dunbasitao deposit is classified as an orogenic gold deposit using the two latest machine learning classifiers based on pyrite trace element data. Fluid immiscibility, sudden cooling, and the substitution of S1− with As1− might be crucial mechanisms leading to Au precipitation. Initial ore-forming fluids brought major amounts of As, Au, Co, Ni, Se, Zn, Ag, Cd, Sn, and other elements, and the Jiangbasitao Formation host rocks contributed a certain amount of As, Ni, Cu, Sb, Pb, and Bi, at least. [ABSTRACT FROM AUTHOR]

To investigate the heavy metal enrichment mechanisms and release characteristics of typical deposits in karst areas, the Sb tailing pond of Dachang, Qinglong, Guizhou Province, China, one of the three largest Sb mines in the word, was selected as the study area. In this study, samples were collected from tailings (0~120 cm) and analyzed for changes in Sb and As content at different pH values by simulated acid rain static release experiments, and solid waste materials (fly ash, quicklime, and zeolite powder) were selected to design an orthogonal test to explore the optimal stabilization effect of Sb and As. The results showed that the average contents of Sb and As exceeded background values of Guizhou soil to different degrees. The content of As leaching revealed slight differences in the leachate. Sb was sensitive to more acidic conditions, and its release content can pose an ecological risk. Further, the best stabilization effect of Sb and As was observed after adding different ratios of fly ash, quicklime, and zeolite powder for a period of maintenance, which can be used as promising stabilizing materials for mine tailings remediation. This study provides comprehensive theoretical support for enhancing source control and risk management of heavy metals. [ABSTRACT FROM AUTHOR]

The Xikuangshan antimony (Sb) deposit is the largest Sb deposit in the world; however, the metal source and cycling and a holistic understanding of the deposit genesis remain equivocal. Sulfur isotope signatures offer a means of fingerprinting different sources in a hydrothermal deposit, although one must be careful to rule out subsequent isotope fractionation during fluid ascent, mixing, and ore precipitation. Here, we investigated the sulfur isotope composition of stibnite occurring at depth in the Xikuangshan deposit to distinguish the isotopic signals from the source and the superimposed imprint from near-surface-derived sulfur mixing or isotopic fractionation. All stibnites from the deep orebodies displayed limited δ34S variation from +6.8‰ to +8.4‰, despite their widely varying depths. These results provide direct evidence that δ34S values measured in deep orebodies are representative of the isotopic composition of initial fluids. The most likely factor controlling the variation of the sulfur isotopes in shallow stibnites (+3.5‰ to +16.3‰) is a series of hydrothermal processes, including Rayleigh fractionation during ore precipitation, fluid boiling induced by pressure release, and/or local input of pyrite from wall rocks via fluid-rock interaction. Accordingly, we conclude that the Neoproterozoic basement served as the metal source. We propose a holistic genetic model wherein we envisage that Sb and S were leached from the basement rocks, and the ore-bearing fluids ascended along a deep fault and eventually precipitated beneath the Devonian shale cap. Thus, sulfur isotopic systematics represent a powerful repository for interrogating the metal source and cycling in the hydrothermal ore system. [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]

In Southern China, the co-occurrence of arsenic (As) and antimony (Sb) contamination in soils around Sb mines presents an environmental challenge. During the flooding period of mining-impacted soils, anaerobic reduction of iron (Fe) oxides enhances the mobilization and bioavailability of Sb and As, further elevating the risk of Sb and As entering the food chain. To address this problem, activated carbon (AC) and biochar (BC) were applied to remediate flooded mining-impacted soils. Our results explored that AC can significantly decrease mobilization by 9–97 % for Sb and 9–67 % for As through inhibiting Fe(III) mineral reduction and dissolution in flooded soils. In contrast, there was no significant effect of BC. This was attributed to the strong adsorption of soil dissolved organic matter (DOM) by AC compared to BC, while DOM as electron shuttle is crucial for microbial Fe(III) reduction. Consequently, the DOM sequestration by AC effectively mitigates Sb and As leaching in contaminated mining soils. [Display omitted] • Activated carbon significantly curtails antimony (9-97 %) and arsenic (9-67 %) release from soil. • Activated carbon inhibits iron mineral reduction in flooded soils. • Activated carbon modulates antimony-arsenic reduction genes expression (arrA and arsC). [ABSTRACT FROM AUTHOR]

[Display omitted] • A resource utilization approach of field AMD for the formation of LDHs was proposed. • LDHs derived from field AMD possesses a larger removal capacity for Sb compared with other LDHs from chemical reagents. • Sb(V) removal by LDHs was attributed to anion exchange and formation of brandholzite. • The removal mechanism of Sb by LDHs was revealed by DFT calculations. Although acid mine drainage (AMD) has been recognized as a major environmental pollutant, it is also a potential source of valuable metals and sulfate. In this study, a resource utilization approach of field AMD for the formation of iron-based layered double hydroxides (LDHs) with sulfate intercalation was proposed and its capacity for removing antimonate [Sb(V)] was examined. Layered double hydroxides derived from field AMD possesses a more rapid equilibration time (<120 min) and a larger removal capacity (78 mg g−1) for Sb(V) compared with other LDHs from chemical reagents. Following the treatment of field AMD containing 10.7 mg L−1 Sb, a residual Sb concentration of 4.0 μg L−1 was achieved using a dose of 1 g L−1 LDHs, which meets the drinking water standard of 5 μg L−1 recommended by China's Ministry of Health. Leaching tests showed negligible metal(loid)s dissolution in Sb-loaded LDHs over a short period. The interactions between Sb(V) and LDHs include anion exchange and formation of brandholzite, which were further investigated at the electronic scale using density functional theory (DFT) calculations. It is envisaged that this approach for preparing LDHs will provide theoretical support for the remediation and resource recovery of AMD. [ABSTRACT FROM AUTHOR]

The Xikuangshan antimony (Sb) deposit is the world's largest known Sb deposit. Due to the lack of suitable minerals for reliable high-precision radiometric dating, it remains difficult to determine the exact age of Sb mineralization in this deposit. Here, we report the first LA-MC-ICP-MS U-Pb ages of syn-stibnite calcite from this deposit. The dating results indicate the presence of at least two stages of Sb mineralization in the Xikuangshan ore district. The calcite-stibnite veins in the Daocaowan ore block probably formed during the Paleocene (58.1 ± 0.9 Ma), representing an early stage of Sb mineralization, while the quartz-stibnite vein in the Feishuiyan ore block probably formed during the Eocene (50.4 ± 4.4 Ma, 50.4 ± 5.0 Ma, and 51.9 ± 1.6 Ma), representing a late stage of Sb mineralization. The new calcite U-Pb ages are significantly younger than the calcite Sm-Nd ages (124.1 ± 3.7 Ma, 155.5 ± 1.1 Ma) reported by previous researchers. We suggest that Sb mineralization of the South China antimony metallogenic belt may be related to tectono-thermal events during Paleogene, possibly linked to high heat flow during the subduction (ca. 60–40 Ma) of the Pacific Plate beneath the Eurasian Plate and/or the Indo–Asian Collision (began at ca. 61 Ma). The young in situ U-Pb ages of calcite challenge the idea of late Mesozoic Sb mineralization in the South China antimony metallogenic belt, suggesting the requirement for more high-precision dating studies. [ABSTRACT FROM AUTHOR]

Antimony (Sb) pollution is causing serious concerns in some regions globally, such as around the XiKuangShan mine in China, which is the largest Sb mine in the world. However, remediation measures are scarce. In this study, we assessed the effects of two fertilisers, sodium dihydrogen phosphate (NaH2PO4 at 200, 500 and 2000 mg kg−1) and calcium chloride (CaCl2 at 20, 80 and 200 mg kg−1), on uptake by rice (Oryza sativa L.) of Sb, cadmium (Cd) and arsenic (As) from contaminated soil under flooded conditions. Despite a very low soil As concentration (10.89 mg kg−1), the results showed that flooded conditions will result in excess accumulation of As in rice grains. NaH2PO4 generally enhanced the release of As and Sb by increasing pH and competitive adsorption in the soil, which resulted in their accumulation in many tissues of the rice plants. NaH2PO4 (200 mg kg−1) significantly reduced soil available Cd concentration by increasing soil pH, which resulted in a decrease in Cd concentration in the roots and husks. CaCl2 at 200 mg kg−1 decreased soil pH, and CaCl2 treatments increased the available Sb concentration, although not as much as NaH2PO4. Both NaH2PO4 and CaCl2 enhanced the formation of root iron plaques, and in many cases increased the concentrations of As, Cd and Sb in the root plaques, suggesting a storage role rather than a barrier of root iron plaques for plant uptake of As, Cd and Sb. CaCl2 at 200 mg kg−1 was the most effective treatment for reducing As, Sb and Cd concentrations in rice grains. We conclude that utilisation of fertilisers containing P on a soil co-contaminated by Sb and Cd poses a risk of Sb and As accumulation under continuous flooded conditions, whereas addition of CaCl2 at 200 mg kg−1 may control As, Sb and Cd accumulation in grains of rice plants under these conditions. Flooding conditions will result in excess accumulation of arsenic (As) in the grains of rice plants. NaH2PO4 generally enhanced the soil release of As and Sb by increasing pH and competitive adsorption in the soil, which resulted in their accumulation in many tissues of the rice plants. The treatment of CaCl2 at 200 mg kg−1 was most effective for reducing As, Sb and Cd concentrations in the grains. [ABSTRACT FROM AUTHOR]

Antimony pollution in the groundwater of the Xikuangshan (XKS) antimony (Sb) mine area in China's Hunan Province has attracted increasing attention. A total of 43 water samples were collected to help understand the hydrogeochemical characteristics, identify the Sb source, and evaluate the water–rock interactions of the Shetianqiao aquifer (SA). The Sb concentrations in shallow and deep SA water samples were 0.1–47.4 mg L−1 and 0.3–19.2 mg L−1, respectively. Stibnite oxidation and leaching from arsenic alkali residue mine wastes were the main Sb sources for the shallow SA water, whereas stibnite oxidation and stronger water–rock interaction were the predominant Sb sources for the deep SA water. The higher Sb concentration (> 10.0 mg L−1) in shallow SA water was predominantly induced by weathering of Sb-bearing minerals, evaporation/concentration effects, and cation exchange, whereas the higher Sb concentration in deep SA water was largely caused by weathering of Sb-bearing minerals, evaporation/concentration effects, ion exchange, and competitive adsorption. These findings provide a more detailed understanding of the geochemical behavior of Sb in groundwater and can be used to develop suitable Sb pollution management strategies. [ABSTRACT FROM AUTHOR]

• Stibnites from a large hydrothermal system reveal a large δ 123Sb range of −0.27 to +0.86‰. • Sulfide separation from the fluid causes significant Sb isotope fractionation, and the best estimated Sb isotope fractionation factor (α fluid-stibnite) is ~0.9994. • Estimated initial Sb isotope composition may constrain potential metal sources. • Sb isotopes can be used to fingerprint hydrothermal fluid flow directionality. In order to characterize antimony (Sb) isotope fractionation in hydrothermal systems, we present Sb isotope compositions of primary stibnite ores from a large Sb deposit in south China. A total number of 39 analyses reveals a large δ 123Sb range of −0.27 to +0.86‰, representing an up to 1.13‰ variation in this hydrothermal system. A gradual increase of Sb isotope ratios from the proximal to the distal parts was observed in stibnite ores. Rayleigh distillation models the systematic variation trend of the Sb isotope values, demonstrating that ore fluids are preferentially enriched in heavier Sb isotopes during the precipitation of isotopically light stibnite. In this way, we consider that separation of stibnite from a Sb-bearing fluid related to reaction kinetics as a cause for Sb isotope fractionation. The modeled data constrain a Sb isotope fractionation factor (α fluid-stibnite) between hydrothermal fluid and stibnite at approximately 0.9994. The model also constrains an initial Sb isotope value of ~0.45‰, which indicates metal sources in the basement rocks of the study area. Given that distal stibnites possess higher Sb isotopic values, Sb isotopes could be used to fingerprint hydrothermal fluid flow and unravel different processes in natural systems. [ABSTRACT FROM AUTHOR]

Wild plant species from three deserted antimony (Sb) mine areas in southern China were collected to measure eight metal(loid)s. Antimony, As (arsenic), Cd (cadmium), Cr (chromium), Cu (copper), Ni (nickel), Pb (lead), and Zn (zinc) concentrations in plants and soil were analyzed. The soils of the mining area was weakly alkaline and contained toxic levels of Sb, As, Pb, Cd, and Zn. Many plant species in the area (40 species and 19 families) have no clear signs of toxicity. The plants were divided into three categories (high, moderate, and low tendency to accumulate metals) based on their (ratio [RT], bioaccumulation factor [BCF], translocation factor [TF]) values. The plants with a high accumulation tendency exhibited the high potential to absorb Sb from contaminated soil; therefore, they can be used for the remediation or phytoremediation of Sb-contaminated soil. [ABSTRACT FROM AUTHOR]

Total concentrations and different forms of antimony (Sb) in soils of Laokuang District (LKQ-1, LKQ-2, LKQ-3), Beikuang District (BKQ-4, BKQ-5, BKQ-6) and Nankuang District (NKQ-7, NKQ-8, NKQ-9, NKQ-10) of Xikuangshan, Hunan province, China were analyzed. The soil Sb concentrations in the whole-ore heap of LKQ-1 and the mining land of NKQ-7 were up to 4258 and 3174 mg/kg respectively, which were both 2000 times above the background soil Sb level in China. In terms of vertical distribution, the Sb concentrations gradually declined with the rise of soil depth. Tessier's 5-step sequential extraction method showed Sb mainly existed in stable forms (organic-matter-bound form, residual form), and the available form accounted for 18%. The proportions of different forms ranked as residual form >iron/manganese oxides >organic-matter-bound form >carbonate-bound form > water-soluble form. Vegetation affected the form distribution of Sb in a complex way and may increase the bioavailability of Sb, so ecological restoration of Sb can be realized through the absorption by vegetation. Analysis of the geoaccumulation index and the potential ecological risk index showed that Xikuangshan was under extremely severe Sb pollution and very serious potential ecological risk. The Sb mining and smelting activities of humans aggravated local Sb pollution. [ABSTRACT FROM AUTHOR]

To assess the health risks caused by soil heavy metal in China's mining areas, concentration data for eight heavy metals in 77 mines were collected from previous literature. Monte Carlo simulation was used to analyze the corresponding carcinogenic risks and noncarcinogenic risks, and sensitivity analysis was carried out for each parameter. The results showed that among the different types of mining areas, multi-metal mines have the highest risk of carcinogenesis, followed by tungsten and antimony mines. Their carcinogenic risk values are all greater than 10−4, which is unacceptable. Pb is a heavy metal with highest noncarcinogenic risk. The log-transformed value is 3.2, which is much larger than the threshold of 0; Pb is followed by As and Hg. Therefore, Pb, As, and Hg are the heavy metals that should be controlled preferentially in polluted mining areas. Sensitivity analysis showed that the soil ingestion rate, exposure frequency, and pollutant concentration level are the factors that have the greatest impacts on health risks. More attention should be paid to these factors when addressing heavy metal pollution in mining areas. In addition, for the surveyed mines, children had a greater health risk than adults, so children should be given extra attention. [ABSTRACT FROM AUTHOR]

Mining activities have introduced various heavy metals and metalloids to surrounding soil environments, causing adverse impacts to the ecological environment system. The extremely high concentration of various heavy metals and metalloids make the Xikuangshan (Hunan, China) an excellent model to assess their ecological risk. In this study, the soil samples from 26 locations of different land use methods in four areas (smelting area, road nearby ore, mining area, and ore tailing area) in Xikuangshan with different levels of various heavy metals and metalloids (Sb, As, Pb, and Cd) were analyzed; in addition, the index of geo-accumulation and the potential ecological risk index were used to evaluate ecological risk. The results showed that the average contents of Sb, As, Pb, and Cd in all soil samples were 4368.222 mg·kg−1, 40.722 mg·kg−1, 248.013 mg·kg−1, and 40.941 mg·kg−1, respectively, implying serious contamination of compound pollution of heavy metals in soil. The concentration of heavy metals in soil among smelting area, road nearby ore, mining area, and ore tailing area showed significant distribution characteristics of region because different mining activities such as smelting, mining, transportation, and stacking caused different pollution intensity. Moreover, the contents of Sb in soil samples decreased successively in residue field, wasteland, forestland, sediment, grassland, and vegetable field, and the contents of Sb in vegetable-field and ecological restoration grassland were relatively low, which indicate that the method of grassland ecological restoration is an effective method to control antimony pollution in soil. The results of ecological risk assessment showed that the antimony mining area was seriously polluted by Sb, As, Pb, and Cd, and had strong ecological risk, and Sb and Cd were the most important pollution factors, which indicated that the pollution of Sb and Cd should be a major concern of relevant departments of environment and health. [ABSTRACT FROM AUTHOR]

Tianshanbeilu is the largest Bronze Age site in eastern Xinjiang, China. Stretching across the entire second millennium BC, it performed a prominent role in connecting the Hexi corridor, Central China and the steppe. A further insight into the metallurgical tradition and the metal supply network is of vital importance to improve our understanding of its multi‐connected nature. This paper offers a new set of chemical and isotopic data on the copper‐based objects at Tianshanbeilu, including alloying elements, trace elements (impurities) and lead isotopes. Combining the concentrations of arsenic and antimony reveals that arsenic was introduced to copper partially due to the use of specific minerals tethrahedrite‐tennantite. Lead isotopes demonstrate that multiple sources of copper were employed at Tianshanbeilu and a majority of them are characterized by common lead, which appears rather different from those of the Central Plains and the Hexi corridor, but highly consistent with local ores. Surprisingly, one object at Tianshanbeilu contains the well‐known highly radiogenic lead. This object undoubtedly marks the westernmost boundary of the distribution of the highly radiogenic lead. We also anticipate that more lead isotopic analyses in NW China will further contribute to the study of the highly radiogenic lead in Central China. [ABSTRACT FROM AUTHOR]

Elevated soil concentrations of antimony (Sb) and co-contaminants are frequently encountered where antimony has been mined on a large scale. For instance, the Xikuangshan antimony mine in central South China has sustained, over many centuries, dispersed and spatially variable input of toxic elements into the soil ecosystem. We utilized this unique environment to assess the impact of geochemical conditions on soil microbiology. Geochemical conditions were assessed by monitoring absolute and available fractions of toxic elements and disrupted soil properties. Soil microbiology was studied by high-throughput sequencing and statistical analysis, including principle component analysis and canonical correspondence analysis. Results show that Sb concentrations were ranged from 970 to more than 24,000 mg/kg. As concentrations were three times higher than the regional background values and ten times higher for Pb, 590 times higher for Cd and 30 times higher for Hg. About 5–10% of the total soil Sb was environmentally mobile. Microbial diversity was high, and soil properties such as pH, organic matter, iron and sulfate controlled the absolute microbial activity. We identified strong positive and negative correlations with specific bacterial taxonomic groups which show: (1) an intolerance of available fractions for all elements, e.g., Gemmatimonas, Pirellula, Spartobacteria; (2) a good tolerance of available fractions for all elements, e.g., Povalibacter, Spartobacteria; and (3) a mixed response, tolerating available Sb, Hg and Cd and inhibition by As, Pb, e.g., Escherichia/Shigella and Arthrobacter, and in reverse, e.g., Gemmatimonas and Sphingomonas. The site hosts great diversity dominated by Gram-negative organisms, many with rod (bacillus) morphologies but also some filamentous forms, and a wide range of metabolic capabilities: anaerobes, e.g., Saccharibacteria, metal oxidizing, e.g., Geobacter, chemoautotrophs, e.g., Gemmata, and sulfur reducing, e.g., Desulfuromonas. The bioremediation potential of Arthrobacter and Escherichia/Shigella for Sb control is highlighted. [ABSTRACT FROM AUTHOR]

Arsenic (As) and antimony (Sb) are both toxic metalloids that are of primary concern for human health. Mining activity has introduced elevated levels of arsenic and antimony into the rivers and has increased the risks of drinking water contamination in China. Due to their mobility, the majority of the metalloids originating from mining activities are deposited in the river sediments. Thus, depending on various geochemical conditions, sediment could either be a sink or source for As and Sb in the water column. Microbes are key mediators for biogeochemical transformation and can both mobilize or precipitate As and Sb. To further understand the microbial community responses to As and Sb contamination, sediment samples with different contamination levels were collected from three rivers. The result of the study suggested that the major portions of As and Sb were in strong association with the sediment matrix and considered nonbioavailable. These fractions, however, were also suggested to have profound influences on the microbial community composition. As and Sb contamination caused strong reductions in microbial diversity in the heavily contaminated river sediments. Microorganisms were more sensitive to As comparing to Sb, as revealed by the co-occurrence network and random forest predictions. Operational taxonomic units (OTUs) that were potentially involved in As and Sb metabolism, such as Anaerolinea, Sphingomonas, and Opitutus, were enriched in the heavily contaminated samples. In contrast, many keystone taxa, including members of the Hyphomicrobiaceae and Bradyrhizobiaceae families, were inhibited by metalloid contamination, which could further impair crucial environmental services provided by these members. [ABSTRACT FROM AUTHOR]

The high geogenic levels of trace metal(loid)s preserved within black shale can be released during natural weathering, causing global concern. Currently, the accumulation, speciation and potential mobilization of two highly toxic metal(loid)s, arsenic (As) and antimony (Sb), from black shale to soils remain unresolved, which hinders the evaluation of their potential risk to surrounding environments. Here, we demonstrate the geochemical enrichment, species transformation, and leaching behavior of As and Sb by applying weathering-induced alteration, sequential extraction and synchrotron-based X-ray absorption near edge spectroscopy (XANES) in the analysis of a range of black shale and weathered samples from two profiles collected from typical Cambrian sedimentary strata of the Pearl River Delta, southern China. The results showed significant accumulation of trace metal(loid)s, including As (43.8–458.0 mg/kg), Sb (7.2–34.5 mg/kg), Cu (8.8–451.0 mg/kg) and Ni (22.2–108.0 mg/kg), in the black shale and weathered products, and high enrichment factors for As (22.0–266.8) and Sb (1.2–6.4) were observed, consistent with the very high degrees of weathering (chemical index of alteration: 83–91). Arsenic in the shale was dominated by arsenate (46–85%), as identified using XANES, and this was resulted from extensive weathering, which facilitated the oxidation of arsenite and arsenopyrite species. Accordingly, significant decreases in sulfide-associated As and Sb were observed in highly weathered products. As a result, As and Sb were primarily in the immobilizable fractions associated with amorphous and well-crystallized Fe/Mn oxides, largely due to the increased formation of secondary Fe (oxyhydr)oxides, including goethite-like minerals, which mainly derived from the oxidative weathering of chlorite-like minerals. Nevertheless, high concentrations of As (<64 μg/L), Sb (14–70 μg/L), and Ni (3–92 μg/L) still leached from black shale samples exposed to synthetic acid rain in the 18-h batch leaching experiment. Our combined characterization results indicated that a small percentage of the high contents of geogenic As and Sb could potentially be released. However, soluble trace metal(loid)s in shale leachate could still endanger surrounding ecosystems, and continual monitoring during long-term natural weathering processes is merited for global black shale regions. • Natural weathering governed the accumulation of trace metal(loid)s in soils derived from black shale • Arsenate dominated in black shale-associated products and soils due to oxidation of reduced As species in oxic environment • In situ-formed secondary Fe-bearing minerals sequestered the pre-released As and Sb from black shale weathering • Low-level but persistent dissolved trace metal(loid)s from black shales still pose ecological risks [ABSTRACT FROM AUTHOR]

• We summarized and discussed about antimony pollution in water environment and its sources. • Research on toxicity of antimony was documented. • Occurrence and biogeochemistry of antimony in water environment were discussed. Antimony, the compounds of which exhibit toxicity, finds extensive usage in industrial processes for flame retardants, plastics, batteries, electronic components, and mechanical bearings. Consequently, mining and industrial activities contribute to the continuous migration of antimony into aquatic environments, influencing the Earth's biogeochemical cycle. Given China's status as the primary global exporter of antimony, the country confronts the challenge of water pollution arising from intensive antimony mining operations. This paper focuses on the latest advances in research concerning antimony toxicity, identifies potential sources of antimony water pollution, and explores its migration pathways and biogeochemistry. Moreover, the study provides estimations of antimony quantities in different compartments. Finally, we discuss the prospects for enhancing our comprehension of antimony's biogeochemical behavior. [ABSTRACT FROM AUTHOR]

Abstract Differences in trophic status can lead to different water quality and sediment geochemistry characteristics, influencing antimony (Sb) mobility in sediments and its release into the water column. In this study, seasonal sampling was conducted in algal- and macrophyte-dominated zones of Lake Taihu, China. High-resolution dialysis (HR-Peeper) and diffusive gradients in thin films (DGT) techniques were used to measure soluble Sb and DGT-labile Sb in the sediment-water profiles at a 4 mm vertical resolution. Results showed that total Sb in sediments from the two zones were on average 3.50 mg/kg and 3.21 mg/kg in the algal- and macrophyte-dominated zones, respectively, with the residual fraction being 96.3% and 95.4% of the total Sb contents in the two zones. In winter, soluble Sb concentrations in both zones increased. This was probably due to the oxidation of Sb(III) to Sb(V) by Mn and Fe oxides. In summer and autumn, soluble Sb concentrations in the algal-dominated region remained low. This is attributed to the dominance of insoluble Sb(III) in sediments under anoxic conditions under eutrophic environments. In contrast, soluble Sb concentrations in the macrophyte-dominated zone were significantly high in summer and were 4.15-times higher than limits set by the World Health Organization (WHO). This likely resulted from the photochemical and rhizospheric oxidation of insoluble Sb(III) compounds. It is suggested that Sb contamination in the sediment-water system of the macrophyte-dominated zone deserves additional attention. Highlights • Antimony (Sb) mobility differed in algae- and macrophyte-dominated (MD) regions. • Photochemical and rhizospheric oxidation increased Sb mobility in the MD region in summer. • Mn and Fe oxide oxidation increased Sb mobility in two regions during winter. • Sb mobilization manifested mainly in the transition between Sb(III) and Sb(V). [ABSTRACT FROM AUTHOR]

Abstract Increasing attention is being paid to Sb as a primary hazardous substance, and further systematic studies of Sb behavior in freshwater wetlands are required. The plain wetlands in Lake Taihu basin located in lower Yangtze River valley, are heavily populated and economically developed area in China. The plain wetlands receive polluted water from point sources (textile and printing plants). In this study, Sb speciation in plain wetlands was investigated and the potential ecological risk of 8 metal(loid)s (As, Cd, Cr, Cu, Ni, Pb, Zn, Sb) were assessed. The mean Sb concentration in the wetlands water is 7.03 μg L−1, which consist of pentavalent, trivalent, organic Sb dissolved in water and a great part that attached to suspend solids (SS). Statistical analysis indicated that Sb(Ⅲ) is dissolved from SS and then further oxided to Sb(V) accompanied with tailing water discharged into wetlands; presence of organic Sb is related to microorganic in eutrophic environment; precipitation of SS is the dominant factor for distribution of bioavailable Sb in surficial sediment. The toxicity coefficient factor for Sb is proposed as 10 and ambient background of 8 metal(loid)s are set up. The potential ecological risk for plain wetlands was 135, which was low level. As, Cd and Sb were main contributors to the ecological risks. The wetlands are threatened by Sb pollution, which should be restrict by reducing the concentration of SS and Sb in tailing water from local water treatment facilities. Graphical abstract Image 10115 Highlights • Sb's toxicity coefficient of 10 was determined and was used to evaluate potential ecological risk of plain wetlands. • Sb speciation in water and sediment of plain wetlands were performed. • The factors affecting the distribution of Sb species in water were analyzed. • The fate of Sb pollutants from textile mill and printing industries plain wetlands was illustrated. [ABSTRACT FROM AUTHOR]

Antimony (Sb) exposure threatens human health. To identify human biomarkers for Sb exposure, we analyzed 480 environmental samples from an active Sb mining area in Hunan, China. Elevated Sb concentrations exceeding the reference level were detected in drinking water (70% of n  = 83 total samples), foods (80%, n  = 188), urine (95%, n  = 63), saliva (44%, n  = 48), hair (80%, n  = 51) and nails (83%, n  = 47). Drinking water contributed 85%–100% of the average daily dose (ADD) of Sb, and the total ADD (11.7 μg/kg bodyweight/day) was up to thirty times higher than the oral reference dose (0.4 μg/kg bodyweight/day) as recommended by USEPA. A positive correlation was found between ADD and Sb content in hair ( p  = 0.02), but not in urine ( p  = 0.051), saliva ( p  = 0.52) or nails ( p  = 0.85), suggesting that hair is the best non-invasive biomarker. Micro X-ray fluorescence analysis indicated that Sb is distributed in discrete spots in hair and nails, and Sb distribution is correlated with other metals. Methylated Sb species were predominant in urine (46%–100%) and saliva (74%–100%) in collected samples, implying that the human metabolic system adopts methylation as an effective pathway to detoxify and excrete Sb. [ABSTRACT FROM AUTHOR]

The road traffic has become one of the main sources of urban pollution and could directly affect roadside soils. To understand the level of contamination and potential sources of trace metals in roadside soils of Shanghai, 10 trace metals (Sb, Cr, Co, Ni, Cu, Cd, Pb, Hg, Mn and Zn) from two urban/rural roads (Hutai Road and Wunign-Caoan Road) were analyzed in this study. Antimony, Ni, Cu, Cd, Pb, Hg and Zn concentrations were higher than that of soil background values of Shanghai, whereas accumulation of Cr, Co and Mn were minimal. Significantly higher Sb, Cd, Pb contents were found in samples from urban areas than those from suburban area, suggesting the impact from urbanization. The concentrations of Sb and Cd in older road (Hutai) were higher than that in younger road (Wunign-Caoan). Multivariate statistical analysis revealed that Sb, Cu, Cd, Pb and Zn were mainly controlled by traffic activities (e.g. brake wear, tire wear, automobile exhaust) with high contamination levels found near traffic-intensive areas; Cr, Co, Ni and Mn derived primarily from soil parent materials; Hg was related to industrial activities. Besides, the enrichment of Sb, Cd, Cu, Pb and Zn showed a decreasing trend with distance to the road edges. According to the enrichment factors (EF s ), 78.5% of Sb, Cu, Cd, Pb and Zn were in moderate or significant pollution, indicating considerable traffic contribution. In particular, recently introduced in automotive technology, accumulation of Sb has been recognized in 42.9% samples of both roads. The accumulation of these traffic-derived metals causes potential negative impact to human health and ecological environment and should be concerned, especially the emerging trace elements like Sb. [ABSTRACT FROM AUTHOR]

The Kuruktag area in Xinjiang is located between the northeastern margin of the Tarim Basin and the South Tianshan orogenic belt, and its complex tectonic background has been extensively studied to assess the tectonic evolution of the Central Asian orogenic belt and the Tarim Craton. Although the Cambrian strata in the study area are well developed and continuous, due to the limitations of the outcrop environment and drilling and seismic data, studies of the sequence stratigraphy and sedimentary evolution have been limited and have yielded results with low accuracy, leading to limited knowledge of the local structure. In this paper, field observations and actual measurements of the stratigraphic profile, supplemented by perimeter logging and seismic data for stratigraphic sequence comparison, are collected, and sea level changes and controlling factors are discussed. Studies have shown that various types of sequence interfaces are present in the Kuruktag area, and three grade II and six grade III type-II sequences can be identified. The grade II and III sequences are composed of a transgressive systems tract (TST) and a highstand systems tract (HST), and the depositional thickness of the TST is less than that of the HST. The northern area has experienced an evolutionary process from a deep-sea basin to a deep-sea shelf, a shallow-water shelf, and a platform edge slope, while the southern area has evolved from a deep-sea basin to a deep-water shelf and shallow-water shelf before again transitioning to a deep-water shelf during the ЄSQ1-ЄSQ6 peroid. The sedimentary facies evolution and sequence structure indicate that the Kuruktag area has experienced a process of rapid large-magnitude transgression and slow regression in terms of sea level. In addition, the curve of sea level change for the Kuruktag area is quite different from the corresponding curves for the Tarim platform facies area and the North China platform. This difference is associated with the evolution of the Kuruktag rift basin. • The sequence boundary is identified, and the sequence stratigraphic division scheme is established. • The sequence−lithofacies paleogeography maps are systematically compiled for the first time. • The process and controlling factors of sea level change are analyzed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Trace element occurrence in orogenic-type pyrite determined by principal component analysis. • Partial least squares discriminant analysis is used to characterize pyrite compositional data. • Random Forests regression reveals potential trace element geothermometer. Orogenic gold deposits represent key global gold resources, yet its internal differences are poorly constrained. Pyrite is ubiquitous in orogenic gold ores, and its trace element geochemistry has significant implications for the ore-forming processes. However, the diffusion regularity and controlling factors of pyrite trace element geochemistry of orogenic gold deposits lack effective constraints. To address these issues, pyrite trace element geochemical data (4092 sets of data) from 67 orogenic gold deposits were compiled for big- data and machine learning analyses. The principal component analysis (PCA) divides the pyrite data into four groups according to trace element correlations: I) Au-As; II) Sb-Cu; III) Ag-Pb-Bi; and IV) Co-Ni-Te-Se-Mo. This division is likely ascribed to the element occurrence in pyrite. Partial least squares-discriminant analysis (PLS-DA) and Random Forests classification were used to identify pyrite trace elemental variations among orogenic deposits of different mineralization ages, wallrocks, and tectono-metallogenic settings. The results show that the influence on pyrite geochemistry from temporal variation is not obvious, and only Triassic and Jurassic orogenic-type auriferous pyrite shows enrichments of Cu, Pb, and Sb, which may reflect the multiple mineralization events in these deposits as Pb commonly occurs as cation in the fluids, while Sb usually occurs in the melt. The spatial difference is more distinct with less overlapping of confidence circles in PLS-DA and higher accuracy in Random Forests, which may have been associated with fluid source variation influenced by the geodynamic setting (mantle model, supposed by distinctive geodynamic variation from metallogenic belts in China) and source strata (metamorphic model, supposed by Archean deposits mostly hosted in green-schist phase besides China). Pyrite in orogenic gold ores hosted in different wallrocks can be differentiated by the different As, Pb, and Cu contents, as the contents of these elements vary widely in the wallrocks and participate in pyrite lattice through fluid-rock reactions. Random Forests regression reveals that pyrite As-Sb contents in pyrite show distinct negative correlations with ore-forming temperature, but Se content shows a non-linear influence. This suggests that the pyrite As-Sb-Se contents in orogenic gold ores can be used as a geothermometer. Furthermore, we suggest that the pyrite Co-Ni contents are not good indicators for the ore-forming temperature, as the low salinity fluid in orogenic gold systems makes Co-Ni difficult to form chloride complexes which is sensitive to temperature variation. [ABSTRACT FROM AUTHOR]

Heavy metals (HMs) in drinking water have drawn worldwide attention due to their risks to public health; however, a systematic assessment of the occurrence of HMs in drinking water treatment plants (DWTPs) at a large geographical scale across China and the removal efficiency, human health risks, and the correlation with environmental factors have yet to be established. Therefore, this study characterised the occurrence patterns of nine conventional dissolved HMs in the influent and effluent water samples from 146 typical DWTPs in seven major river basins across China (which consist of the Yangtze River, the Yellow River, the Songhua River, the Pearl River, the Huaihe River, the Liaohe River and the Haihe River) for the first time and removal efficiency, probabilistic health risks, and the correlation with water quality. According to the findings, a total of eight HMs (beryllium (Be), antimony (Sb), barium (Ba), molybdenum (Mo), nickel (Ni), vanadium (V), cobalt (Co) and titanium (Ti)) were detected, with detection frequencies in influent and effluent water ranging from 2.90 (Mo) to 99.30% (Ba) and 1.40 (Ti) to 97.90% (Ba), respectively. The average concentration range was 0.41 (Be)− 77.36 (Sb) μg/L. Among them, Sb (exceeding standard rate 8%), Ba (2.89%), Ni (21.43%), and V (1.33%) were exceeded the national standard (GB5749–2022). By combining Spearman's results and redundancy analysis, our results revealed a close correlation among pH, turbidity (TURB), potassium permanganate index (COD Mn), and total nitrogen (TN) along with the concentration and composition of HMs. In addition, the concentration of HMs in finished water was strongly affected by the concentration of HMs in raw water, as evidenced by the fact that HMs in surface water poses a risk to the quality of finished water. Metal concentration was the primary factor in assessing the health risk of a single metal, and the carcinogenic risk of Ba, Mo, Ni, and Sb should be paid attention to. In DWTPs, the removal efficiencies of various HMs also vary greatly, with an average removal rate ranging from 16.30% to 95.64%. In summary, our findings provide insights into the water quality and health risks caused by HMs in drinking water. [Display omitted] • First study to assess nine heavy metals in 146 DWTPs across China. • High levels of Ba, Ni, Sb, and V were exceeded the guideline recommended by the China. • Strong correlations exist between the pH, turbidity, COD Mn, TN and heavy metals. • The health risk of Ba, Mo, Ni, and Sb should be concerned. • The mean removal ratios of heavy metals in the studied DWTPs were 16.30–95.64%. [ABSTRACT FROM AUTHOR]

[Display omitted] • The metallogenic link among Au, Sb and Hg has been identified. • Sulfur in the Au-Sb-Hg-rich fluids derived from the Cambrian ore-bearing strata via thermal-chemical sulfate reduction process. • Fluid-rock interaction and changes of temperature and oxygen-sulfur fugacity are responsible for Au and Sb mineralization, respectively. • The Au-Sb-Hg deposits are best classified as orogenic type. The turbidite-hosted Au-Sb-Hg deposits in the Sandu-Danzhai area are distributed along the southwestern marginal fault of the Jiangnan Orogen, yet any genetic link among the Au, Sb and Hg mineralization and their respective ore-forming process remain unclear. Here, we investigate the Paiting Au(-Hg) and Miaolong Au-Sb deposits and present a new metallogenic model based on detailed petrographic observations, and in-situ trace element (EPMA and LA-ICP-MS) and sulfur isotope (fs-LA-MC-ICPMS) analyses on sulfide minerals. Our results show that the ore formation in the Sandu-Danzhai metallogenic belt (SDMB) can be divided into Au (pyrite + arsenopyrite + dolomite), Au-Sb (pyrite + arsenopyrite + stibnite + quartz), Sb (stibnite + native antimony + barite + dolomite + quartz) and Hg (cinnabar + calcite) stages, based on mineral paragenetic and vein crosscutting relationships. Trace element compositions suggest that progressive As enrichment in pyrite is accompanied by increasing Au, Sb and Cu contents, implying that these elements may have been leached from the same source via fluid-rock reactions. Sulfur isotope compositions of the sulfates and sulfides in the Au-Sb-Hg ores reveal that the sulfur was originated from thermal-chemical sulfate reduction (TSR) of marine sulfates in the Cambrian ore-bearing strata. Thus, we propose that deep metamorphic fluids (as evidenced from the high fluid CO 2 and CH 4 contents) may have promoted ore-material (e.g., Au, Sb, As, Hg) mobilization in the metamorphic basement and/or Cambrian strata. As for the metal transport and precipitation mechanism, fluid-rock interaction may have decreased the ore-fluid As content and caused auriferous pyrite precipitation. Meanwhile, changes in temperature and oxygen-sulfur fugacity may have significantly decreased Sb solubility, leading to extensive stibnite precipitation. Cinnabar associated with calcite was likely deposited via carbonate dissolution in the Cambrian strata in late hydrothermal (waning) stage. Overall, we propose that the Au-Sb-Hg deposits in the SDMB are best classified as orogenic type, and the metallogeny was controlled by boundary faults of the Jiangnan Orogen. [ABSTRACT FROM AUTHOR]

Xikuangshan is located in Lengshuijiang City, Hunan province, China. With intensive mining and metallurgical activities, large amounts of tailing containing heavy metals (in this study, the term “heavy metals” is used for both metals and metalloids) were introduced to the soils around the mine area. Those heavy metals including antimony and other heavy metals would pose huge risk to human health and ecological environment. With a view to providing information on the extent of contamination and potential ecological risk of heavy metals in the soils of this mine area, the total contents of antimony (Sb), manganese (Mn), zinc (Zn), arsenic (As), cadmium (Cd), and lead (Pb) in the soils were examined. The results revealed that the predominant pollutants in this area were Sb, Cd, and Zn with mean concentrations being 356.58, 9.98, and 486.42 mg kg−1, 119.66, 117.41, and 5.17 times of the corresponding background values respectively. The pollution indices (Ps) indicated that the pollution levels of all sampling zones were serious including the control zones. The ecological risk levels of all heavy metals were very high on all the sampling zones except sampling zone 7 (as considerable), and Sb, Cd, and As were regarded as making great contribution to the risk indices (RI). [ABSTRACT FROM AUTHOR]

Since environmental geochemical behavior of antimony (Sb), especially Sb speciation in aquatic system were largely unknown, studies were conducted in various waters and sediments from the world's largest antimony mine area at Xikuangshan (XKS). Based on samples collection, total and speciation of Sb and several aquatic environmental parameters were determined in waters from river, well, reservoir, wastewater and sediments. Sb(V) was found as the predominant speciation in the waters and sediments. The environmental geochemical behavior of Sb speciations were mainly controlled by the process of oxidation and adsorption/combination with environmental matrix, mainly as Fe/Al (hydr)oxide, and oxidation may has higher priority than adsorption in the aquatic system. Spatial distribution of decreased Sb concentrations in some surface waters resulted from the dilution effect of river/reservoir/tributary water and adsorption of environmental matrix. The declined temporal distributions of Sb in waters compared with previous studies were attributed to several restoration measures and less mining/smelting activities in XKS. Results suggested that tailings heaps in mining region should arouse much attention for its potential release of Sb. [ABSTRACT FROM AUTHOR]

The Xikuangshan (XKS) mine, the world's largest antimony (Sb) mine, was chosen for a detailed Sb isotopic signature study owing to its historical Sb contamination of water systems. Hydrochemical data, in particularδ123Sb values, were analyzed to identify the Sb source and predominant geochemical processes that affect Sb mobilization in different waters. The δ123Sb values of waters from the XKS Sb mine range from − 0.20‰ to + 0.73‰. In particular, the δ123Sb values of the main Feishuiyan stream do not significantly vary (+0.19‰-+0.24‰), while those of groundwater in different aquifers (−0.08‰ to +0.73‰) and mine water in different adits (−0.20‰ to +0.37‰) vary over a wide range. The relationships between δ123Sb values and Sb concentrations indicate that a simple dilution of Sb and a weak Sb adsorption onto Fe/Mn suspended particles and sediments in the Feishuiyan stream may occur, oxidative weathering and leaching infiltration of Sb-containing waste rocks and slags may cause variations in the δ123Sb values in groundwater, and Sb mobilization in the mine water is influenced by a combination of processes (oxidative dissolution, adsorption of Fe/Mn (hydr)oxides, and mixing). A conceptual hydrogeochemical model was summarized to elucidate the Sb source and mobilization in water systems from the XKS Sb mine. [Display omitted] • The δ123Sb values of waters from the XKS Sb mine range from − 0.2‰ to + 0.73‰. • Both adsorption onto Fe/Mn (hydr)oxides and mixing occur in mine water. • The source and mobilization of Sb are closely related to the mining activities. • A conceptual model of Sb source and mobilization in water systems was proposed. [ABSTRACT FROM AUTHOR]

Landfill-induced heavy metal (HM) contamination of soils is a widespread and complex problem. The levels and potential hazards of HM contamination in landfills must be evaluated before they can be reused for any purpose. In order to reuse a historical landfill in northern China, 376 sampling sites were selected in 2019 using the checkerboard layout method, and the levels of arsenic (As), mercury (Hg), antimony (Sb), copper (Cu), lead (Pb), cadmium (Cd), nickel (Ni), zinc (Zn), and thallium (Tl) in the soil were measured. Multiple evaluation methods established the HM pollution levels, agricultural suitability, and health risks associated with the sampling sites. In most parts of the study area, the concentrations of all nine HMs exceeded the screening levels and maximum allowable concentrations for agricultural soils. Only the soils in Zones 5 and 6 can be used for agricultural activity. Moreover, the deep soils were heavily contaminated with HMs in certain areas, possibly because of leaching and infiltration in the surface soil and the rise and diffusion of polluted groundwater. The soil HMs in the study area posed a higher carcinogenic risks to both adults and children. The average carcinogenic risk associated with As was 6.12 × 10−4, which was the major contributor to carcinogenic risk at all HM-contaminated sites. The results of this work empirically demonstrated that soil HM pollution is severe and problematic in the study area and remedial measures are urgently required. [Display omitted] • Nine HMs measured at 376 sampling sites at historical landfill in Northern China. • As & Ni contributed to the majority of the HM burden in adjacent soil & groundwater. • Arsenic was associated with the highest carcinogenic risk to children and adults. • Most sites in the study area are unsuitable for farming & crop cultivation purposes. [ABSTRACT FROM AUTHOR]

China has the most abundant antimony (Sb) resources of any country in the world. Large quantities of Sb have been released from mining and smelting processes, causing serious Sb contamination in the mine or nearby areas. To understand the leaching characteristics of hazardous Sb, As, Pb and Cr from antimony minerals, 12 samples of antimony-bearing ores from eight large mines from China distributed in Hunan, Yunnan, Guizhou and Guangxi provinces were studied. The main compositions of these minerals are Sb 2 S 3 , SiO 2 or CaCO 3 . The pH changes during the leaching indicated that some minerals themselves are alkaline, providing sufficient acid neutralizing capacity during leaching. However, some alkaline minerals release much more Sb, As, Pb and Cr than others. Inconsistencies between totals amounts and the released content of Sb, As, Pb and Cr were also found. The surface topography of an antimony sulfide mineral and the species changes of Sb and sulfur (S) on its leached surface were also characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), respectively. It is the oxidation dissolution of Sb 2 S 3 that releases Sb. Sb(III) and S 2 − on the surface of the fresh mineral were oxidized to Sb(V) and S 2 O 3 2 − and SO 4 2 − , respectively, and finally, an equilibrium of dissolution was reached over time. The release of Sb, As, Pb and Cr from typical antimony ores is a source of Sb, As, Pb and Cr in the weathering zone; with this in mind, it is easier to understand the geochemical processes and the pollution accidents involving Sb and As within the mining areas and their surroundings. [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]

The Xikuangshan (XKS) mine, an antimony mine that has been active for more than a century, was chosen for a detailed antimony hydrogeochemical study because of the historical antimony contamination in local bedrock aquifers. Hydrochemical data, δ34S values of dissolved SO 4 2−, and δ98Mo values were analyzed to identify the predominant geochemical processes affecting Sb attenuation within the aquifers. Groundwater from the adits at the XKS Sb mine reflects an oxidizing environment and has pH values between 6.81 and 8.89 because of the sufficient acid-neutralizing effect of carbonates. The decrease in Sb concentrations along the groundwater flow direction and the highly coloured deposits in the adits indicate Fe and Mn oxides have a significant capacity for Sb sorption. The δ34S values of the groundwater indicate that reductive dissolution of Fe(III) hydroxides is not the dominant process controlling Sb mobilization. Furthermore, the δ34S values and weak-alkaline groundwater corporately suggest that Sb adsorption on and desorption from Fe/Mn (hydr)oxides may both occur, with adsorption being more significant than desorption with respect to Sb attenuation in groundwater. The δ98Mo values of the groundwater further demonstrate that this adsorption is relatively significant in terms of Sb attenuation, and that competitive adsorption may occur between Sb and As in groundwater at the XKS Sb mine. Overall, the hydrochemistry analysis, especially the S and Mo isotope evidences collectively elucidate that the attenuation of Sb in groundwater from the XKS Sb mine are influenced by several geochemical processes, including: (1) more adsorption on than desorption from Fe/Mn (hydr)oxides; (2) competitive adsorption of arsenic; and (3) dilution with low-Sb groundwaters. This study demonstrates that hydrochemical analyses, particularly S and Mo isotope studies, are useful for tracking Sb attenuation in groundwater from antimony-contaminated mine areas. [Display omitted] • S and Mo isotopes were used to elucidate the attenuation of Sb in bedrock aquifer. • Adsorption on Fe/Mn (hydr)oxides is relatively significant in terms of Sb attenuation. • A competitive adsorption may occur between Sb and As. • A conceptual model of Sb attenuation in bedrock aquifer system was proposed. [ABSTRACT FROM AUTHOR]

[Display omitted] • LWJ-JDW selected to test hypotheses of world-class Sb cluster in South China. • Orebodies localization is controlled by a NE-trending sinistral shearing system. • Multistage mineralization initiated from ∼252 Ma and terminated at ∼205 Ma. • Metals of Sb-Au sourced from host and underlying strata by metamorphic fluids. • LWJ-JDW resemble the epizonal orogenic Sb-Au deposits in South China. The Xiangzhong (XZ) Basin and its neighboring Xuefengshan (XFS) Mountain in South China, as one of the world-class antimony (Sb) producers, have provided appropriately 67% of globally exploited Sb metal (0.46 million tons) in human history. The associated gold (Au) with Sb in this region is also of significant economic values. In previous studies, these Sb-Au deposits were debated as a diversity of genetic types such as epithermal, magmatic-hydrothermal, sedimentary exhalative (SEDEX) and orogenic Sb-Au deposits. To evaluate these genesis hypotheses, we select the representative Longwangjiang-Jiangdongwan (LWJ-JDW) orefield to reveal the Sb-Au accumulation process and metal-fluid sources of these deposits. Our orefield-scale structural analysis shows that the localization of principal Sb-Au orebodies is controlled by a NE-striking sinistral shearing system composed by an integrated set of NE-striking and SE-dipping fractures in the pre-ore folded Neoproterozoic Wuqiangxi slate. Two chief ore periods were identified, including the marine sedimentation (S I , pyrite nodular) and tectonic-metamorphic hydrothermal period (S Ⅱ −S Ⅳ , Sb-Au veins). The second period is further subdivided into three stages of S Ⅱ (pre-tectonic deformed pyrite-milky quartz veins), Siii (syn -tectonic pyrite-arsenopyrite-stibnite-quartz veins) and S Ⅳ (post-tectonic stibnite-calcite veinlets). It is notable that gold precipitation is significantly prior to Sb ores at LWJ-JDW. Three sericite samples throughout S Ⅱ −S Ⅳ yield a group of well-defined 40Ar/39Ar plateau ages (253 ± 4, 234 ± 3 and 206 ± 2 Ma, respectively). This indicates the multistage Sb-Au mineralization initiated from Early Triassic and terminated at Late Triassic time. Further trace elements analyses show the earliest nodular Py I is enriched in a list of As, Ni, Sb, Cu, Se, Co, Pb, Zn and Ti that can be analogy to the diagenetic pyrite in the organic-rich marine sedimentary rocks. Extremely high Sb (median, 1107 ppm) and mediate Au (0.07 ppm) are monitored in Py I , indicative of the initial Sb and Au involvement from the Neoproterozoic sedimentation. Comparably, sulfides of the later S Ⅱ −S Ⅳ possess a similar spectrum of trace elements but with highly variable concentrations. All the sulfide generations host the wide range of in-situ δ34S V-CDT values (–23.9 to −3.7‰ for S Ⅰ , −7.6 to −2.9‰ for S Ⅱ −S Ⅳ , respectively), indicating sulfur originally sourced from bacterial sulfate reaction (BSR) of the Neoproterozoic seawater sulfates, and then gradually reduced by thermochemical sulfate reaction (TSR) during the subsequent Au-Sb-induced tectonic-metamorphic hydrothermal activity. The lead isotope compositions in accordance with the evolution lines of upper crust and orogen, implying that the Pb were chiefly sourced from host slate of the Wuqiangxi Formation and its underlying basement. Synthesis of these data, we proposed that the Sb-Au accumulation at LWJ-JDW was caused by the multistage mineralization from Neoproterozoic marine sedimentation to Triassic episodic deformation and metamorphic processes (253–206 Ma). [ABSTRACT FROM AUTHOR]

Arsenic and antimony are widely distributed toxic metalloids in aquatic environments. However, their partitioning behaviors in the sediment profile remain not well understood. Here, partitioning behaviors, diffusive fluxes, as well as the ecological risks of As and Sb in the sediment–porewater profile system in the tributaries of the Three Gorges Reservoir (TGR) were investigated. As and Sb showed markedly different spatial variations in the longitudinal profiles of both porewater and sediment samples. Specifically, the concentration of As showed an accumulation trend with depth, while that of Sb showed a relatively complicated trend. Further, As showed lower sediment-porewater partitioning coefficient (K d) values, suggesting that it had a relatively lower sediment affinity and a higher mobility than Sb. Its residual fraction (30%–60%) was also lower than that of Sb. This phenomenon could be attributed to the chemical fractions of the trace metals and the pH value of the sediments. Furthermore, the K d values corresponding to As were influenced by both the residual fraction (r = 0.338, p < 0.05) and the exchangeable fraction (r = −0.643, p < 0.01), while those corresponding to Sb were only influenced by pH. Additionally, even though these two trace metals showed low ecological and mobility risks, the diffusive fluxes at the sediment-water interface suggested that the sediment acted as a source of As and a sink for Sb relative to the overlying water. This study indicated that As and Sb had different partitioning behaviors and release risks in the sediment–porewater profile system, enhanced the understanding the transport and fate of As and Sb in the aquatic environment. [Display omitted] • Partitioning behavior of As and Sb in the sediment-porewater profile was studied. • As and Sb showed different spatial variations in the longitudinal profiles. • Partitioning coefficient showed that Sb had a higher affinity and lower mobility than As. • Sediment acted as a source of As and a sink for Sb relative to the overlying water. [ABSTRACT FROM AUTHOR]

Background Exposure to metals, including essential and nonessential elements, has been linked to male reproductive health in animals. However, findings from human studies are inconsistent. Objective To examine the associations between metal exposure at environmental levels and semen quality in a Chinese population by performing repeated measurements of urinary metals to estimate individual-level exposure. Methods From March to June 2013, 1052 men seeking semen evaluation were recruited from the Reproductive Center of Tongji Hospital in Wuhan, China. Each man provided one semen sample and two urine sample. Semen quality parameters and urinary levels of 18 metals were determined. Associations between the urinary metal levels and semen quality parameters were assessed using confounder adjusted linear and logistic regressions. Restricted cubic spline analysis was performed to assess dose-response relationships between continuous metal measurements and outcomes. Results Urinary levels of cadmium were significantly inversely associated with progressive sperm motility and total motility (both P < 0.02) based on multivariable linear regression models, consistent with the trends of increased odds ratios for below-reference semen quality parameters observed in the logistic models (both P < 0.05). Additionally, we found significant inverse associations of urinary molybdenum and lead with percentages of normal sperm morphology (both P < 0.05). These associations remained suggestive or significant after adjustment for multiple testing. They were also robust to the simultaneous consideration of multiple metals, and curves of restricted cubic spline showed clear dose-response relationships. Conclusion Our findings suggest that environmental exposure to cadmium, molybdenum and lead may contribute to a decline in human semen quality. [ABSTRACT FROM AUTHOR]

Although similar geochemical behaviors of arsenic (As) and antimony (Sb) in the environment has been assumed and widely reported, growing evidence suggests the two elements cannot, under some conditions, be assumed to behave similarly. In this four-year study (samples collected in each year), comparative investigation of the biogeochemistry of As and Sb in water/fish, soil/vegetable, tailings/plant samples were carried out at the world's largest active Sb mine area (Xikuangshan, China). Depending on duration the tailings had been stacked, significant differences in spatial distributions between As and Sb were found, and these were associated with change in pH over time. Bio-accumulation factors (BAFs) of As were approximately 10-fold greater than those of Sb in fish/water, plant/tailing, and vegetable/soil systems. Sb had higher BAF in non-fatty tissues such as gills of fishes and shells of crabs. BAFs of Sb in vegetable/soil exhibited insignificantly, but different from As, positive correlation with pH in soil. [ABSTRACT FROM AUTHOR]

Heavy metal pollution in soils caused by mining and smelting has attracted worldwide attention for its potential health risks to residents. This paper studies the concentrations and accumulations of Sb and As in both soils and vegetables and the human health risks of Sb and As in vegetables from Xikuangshan (XKS) Sb mine, Hunan, China. Results showed that the soils were severely polluted by Sb and As; Sb and As have significant positive correlation. Sb and As concentrations in vegetables were quite different: Coriandrum sativum L. was the highest in Sb, Allium fistulosum L. was the highest in As, and Brassica pekinensis L. was the lowest in both Sb and As; Daucus carota L. and Coriandrum sativum L. showed advantage in accumulating Sb and As; Coriandrum sativum L. had higher capacity of redistributing Sb and As within the plant. Health risk assessment results showed that the hazard quotient (HQ) values of Sb and As in vegetables were in the ranges of 1.61–3.33 and 0.09–0.39, respectively; the chronic daily intake (CDI) and hazard quotient (HQ) values of Sb were over the safe limit recommended by FAO and WHO, indicating that long-term consumption of vegetables from the surrounding soils of XKS mine may bring health risks to residents. [ABSTRACT FROM AUTHOR]

[Display omitted] • AAO process with novel amPAN adsorbent was developed to treat composite wastewater. • Effects of aniline and antimony on substrate removal in AAO process were explored. • Release of PN was more susceptible than PS in presence of aniline and antimony. • Evolved microbial community was responsible for substrate removal improvement. • COD (94.4%), NH 4 +-N (92.6%), TN (76.4%) and TP (93.4%) were removed in Stage 3. There has been increasing concern over the mixed discharge of municipal-textile composite wastewater, which remains challenging for typical wastewater treatment plant (WWTP) using anaerobic-anoxic–oxic process (AAO). Highly-toxic aniline and antimony, typical co-contaminants in textile wastewater, usually lead to increased chemical oxygen demand (COD) in influent and deteriorated effluent quality. Amidoxime-modified polyacrylonitrile (amPAN) adsorbent was prepared and added to adsorb antimony and facilitate substrate removal. With amPAN dosage at 6.0 g L−1 in oxic bioreactor, 64.2 ± 5.6% of antimony was removed from influent. Extracellular polymeric substance release was simultaneously changed with residual antimony concentration. Meanwhile, amPAN promoted the proliferation of Proteobacteria , Bacteroidetes and Epsilonbacteraeota serving as microorganism carrier. As a result, removal efficiencies of COD (94.4 ± 0.6%), ammonium (NH 4 +-N, 92.6 ± 3.3%), total nitrogen (TN, 76.4 ± 6.3%) and total phosphorus (TP, 93.4 ± 2.1%) were enhanced to meet Class 1A discharge standard in China. These results indicate that AAO with amPAN is promising for municipal-textile composite wastewater treatment. [ABSTRACT FROM AUTHOR]

The authors studied the concentration of heavy metals and mercury fractionation in contaminated soil in 2 agricultural land use systems (paddy rice and dry land) at the Wanshan mercury mine in China. The average concentrations of chromium, lead, copper, nickel, and zinc were generally lower in paddy rice soil relative to corn field soil. Soil under corn field production was slightly contaminated with lead (22-100 mg/kg), copper (31-64 mg/kg), and nickel (22-76 mg/kg) and moderately contaminated with zinc (112-635 mg/kg). In both soils, correlation of these metals with the titanium concentration in the soil indicates a geogenic origin for each metal (lead, r = 0.48; copper, r = 0.63; nickel, r = 0.47; zinc, r = 0.48). The mercury and antimony concentration in soil was high under both cropping systems, and future remediation efforts should consider the potential environmental risk presented by these metals. The concentration of bioavailable mercury in soil ranged from 0.3 ng/g to 11 ng/g across the 2 cropping systems. The majority of mercury (>80%) was associated with organic matter and the residual fraction. However, soil under paddy rice production exhibited a significantly lower concentration of Fe/Mn oxide-bound mercury than that under corn field production. This may be a function of the reduction of Fe/Mn oxides in the paddy rice soil, with the subsequent release of adsorbed metals to the soil solution. Sequential change from corn field to paddy rice production, as practiced in Wanshan, should therefore be avoided. Mercury adsorbed to Fe/Mn oxides in corn field soil potentially could be released into the soil solution and be made available for biomethylation under the flooded water management conditions of a rice paddy. Environ Toxicol Chem 2014; 33:2147-2155. © 2014 SETAC [ABSTRACT FROM AUTHOR]

The present work investigated the adsorption of Sb(III) and Sb(V) on five sediment samples (Pearl River, Yangtze River, Yellow River, Yongding River, and Liao River) from typical water systems in China and the adsorption of Sb(V) on Pearl River sediment with different organic carbon (OC) fractions using batch experiments. In order to assess the contributions of sedimentary organic components to the overall adsorption of pentavalent Sb on sediments, one sediment sample was treated by commonly used chemical and physical methods to remove different organic components. Experimental data of Sb(III) and Sb(V) adsorption on five sediments were successfully modeled using the Freundlich (r2> 0.96) isotherm. In general, the sediments with high Fe and Al oxide contents and total organic carbon (TOC) had higher Sb(III) and Sb(V) adsorption than the sediments containing small amounts of Fe and Al oxides and TOC. Dissolved organic carbon (DOC) in sediment promoted the adsorption of Sb(V), and humin fractions and black carbon-like material in sediment had a high affinity for Sb(V). [ABSTRACT FROM PUBLISHER]