High Concentrations Of Sb Research Articles

Microbial metabolic activity in metal(loid)s contaminated sites impacted by different non-ferrous metal activities

Many non-ferrous metal mining and smelting activities have caused severe metal(loid) contamination in the local soil environment. The metabolic activity of soil microorganisms in four areas affected by different metallurgical activities (production vs. waste disposal) was characterized using a contamination gradient from the contaminated site to the surrounding soils. Results indicated that the soil microcalorimetric and enzyme activities were correlated with the fractionated metal(loid) properties (p < 0.05). All four areas had high total As, Cd, Pb, Sb, and Zn concentrations, of which mobile As, Cu, Ni, Pb, Sb, and Zn were higher in the contaminated sites than the surrounding sites, reflecting an elevated environmental risk. Three contaminated site areas had lower microbial activities than their surrounding sites suggesting that high metal(loid) concentrations inhibited soil microbial communities. Interestingly, the fourth area (tailing pond) showed an opposite trend (i.e., increased microbial activity in contaminated vs. surrounding areas). The microbial thermodynamic parameters of this contaminated site were higher than its surrounding sites, suggesting that the selected microbial communities can develop a functional resistance to metal(loid)s stress. This study provides a theoretical basis for ecological prevention and control of metal-polluted areas.

Effects of antimony exposure on DNA damage and genome-wide variation in zebrafish (Danio rerio) liver

Antimony (Sb) is a potentially toxic and carcinogenic cumulative contaminant that poses a serious threat to aquatic ecosystems. To better clarify the genotoxicity of Sb and its mechanism of action. In this study, we investigated DNA damage and genome-wide variation in the liver of a model organism, zebrafish (Danio rerio), under subacute Sb exposure and explored its potential toxicological mechanisms. The results showed that medium and high concentrations of Sb significantly reduced the total antioxidant capacity and increased the content of reactive oxygen species in zebrafish liver, and further studies revealed that it increased oxidative DNA damage and DNA-DNA cross-link (DDC), but had little effect on DNA-protein cross-link (DPC). The result of resequencing showed that the mutation sites of the genes with high concentrations of Sb were higher than those with medium concentrations, and the mutation was mainly a single nucleotide. The pathways significantly enriched for nonsynonymous single nucleotide polymorphisms (SNPs) and insertion/deletion mutations (InDels) variant genes in the coding regions of both the medium and high Sb-treated groups were ECM-receptor interactions, and the high Sb-treated group also included lysine degradation, hematopoietic cell lineage, and cytokine-cytokine receptor interactions. This suggests that ECM-receptor interactions play an important role in the mechanism of antimony toxicity to the liver of zebrafish.

Soil microbial responses to simultaneous contamination of antimony and arsenic in the surrounding area of an abandoned antimony smelter in Southwest China

Soil contamination with heavy metal(loid)s may influence microbial activities in the soil, and consequently jeopardize soil health. Microbial responses to soil contamination play an important role in ecological risk assessment. This study investigated the effect of heavy metal(loid)s contamination on microbial community structure and abundance in the surrounding soil of an abandoned antimony (Sb) smelter in Qinglong county, Guizhou province, Southwest China. A total of 46 soil samples were collected from ten sampling sites (labelled as A–I, and CK) across the study area at depths of 0–2, 2–10, 10–20, 20–30, 30–40, and 40–50 cm. The soil samples were analyzed for total and bioavailable heavy metal(loid) concentrations, bacterial, fungal, and archaeal community structures, diversities, and functions, together with soil basic physicochemical properties. Much greater ecological risk of Sb and arsenic (As) was present in the surface soil (0–2 cm) compared to that in the subsoils. The activities of dominant microorganisms tended to be associated with soil pH and heavy metal(loid)s (i.e., Sb, As, lead (Pb), cadmium (Cd), and chromium (Cr)). Bacteria associated with IMCC26256, Rhizobiales, Burkholderiales, and Gaiellales, and archaea associated with Methanocellales were estimated to be tolerant to high concentrations of Sb and As in the soil. In addition, the magnitude of soil microbial responses to Sb and As contamination was in the order of archaea > bacteria > fungi. In contrast to the negligible response of fungi and negative response of bacteria to Sb and As contamination, there was a strongly positive correlation between archaeal activity and total Sb and As concentrations in the soil. Our findings provide a theoretical basis for the remediation of Sb smelter-affected soil.

Antimony oxidation and whole genome sequencing of Phytobacter sp. X4 isolated from contaminated soil near a flotation site.

The conversion of the more toxic Sb(III) into less toxic Sb(V) is an effective strategy for the treatment of antimony-contaminated sites. In this study, a strain, Phytobacter sp. X4, which can tolerate high concentrations of antimony and can use nitrate as an electron acceptor for Sb(III) oxidation under anaerobic conditions, was isolated from the deep soil of an antimony mine flotation tailing. Unlike other antimony oxidizing bacteria, X4 oxidized better under high Sb(III) concentration, and the oxidation efficiency of 10mM Sb(III) reached the maximum at 110h with 61.8 %. Kinetic study showed X4 yielded a Vmax of 1.093μM∙min-1 and a Km of 718.2μM. The genome of Phytobacter sp. X4 consists of a complete circular chromosome and two plasmids. In addition, X4 had more metal(loid)s resistance genes and highly expressed genes than other Phytobacter spp., reflecting its stronger adaptive advantage in harsh survival environments. We also analyzed the origin and evolution of arsB, arsC, and arsH, which may have been transferred horizontally from other species. iscR and arsH may have an important contribution to Sb(III) oxidation. Thus, Phytobacter sp. X4 has a good ability to remediate high antimony-contaminated sites and can be applied to an anaerobic environment.

New insights into the genesis of the Sipingshan gold deposit in eastern Heilongjiang, north-eastern China: Evidence from geology, U-Pb and Rb-Sr geochronology, geochemistry, and H[sbnd]O[sbnd]S-Pb isotopes

The Sipingshan gold deposit is intermediately sized and located in the eastern Wandashan Terrane. It has attracted much attention for its uncommon genetic type of hot spring. Gold orebodies mainly occur in the upper and lower siliceous rocks, siliceous cemented breccia is found between the upper and lower siliceous rocks, and silicified rhyolite porphyry is observed below the lower siliceous rocks. Two main mineralisation periods (i.e. exhalative sedimentation and hydrothermal superimposition) have been identified at Sipingshan based on mineral paragenesis and crosscutting vein relationships. In this study, analyses of whole-rock geochemical compositions, pyrite Rb–Sr age, zircon U–Pb–Hf contents, and S–PbOH isotopes were conducted to determine the Au mineralisation time and ore genesis of this deposit. The ore-bearing siliceous rock revealed weighted mean 206Pb/238U ages of 121.8 ± 1.1 Ma and 117.6 ± 1.0 Ma, representing the mineralisation age of the exhalative sedimentation period. The Rb–Sr isochron age of pyrites (106 ± 3 Ma) was consistent with the Au–Cu mineralisation age in the Wandashan area and represented magmatic–hydrothermal mineralisation. The siliceous rocks were characterised by high SiO2 (97.92–99.18 wt%), low TiO2 (0.01–0.03 wt%), low Al2O3 (0.22–0.55 wt%), negative δCe (0.78–1.00), positive δEu (1.12–4.04), and low Sb, As, Cs, Cd and Li contents, indicating the genesis of hydrothermal sediments. The OH isotope results suggested that the ore-forming fluids were mainly derived from magmatic water and mixed with meteoric water in the later stage. The δ34S values of pyrites from the siliceous rocks (–25.8 to –8‰) indicated a biogenic sulfur-dominated source, corresponding to the exhalative sedimentation period. The δ34S values of pyrites (9.8 to 29.7 ‰ and –1.9 to –4.7 ‰) formed in the magmatic–hydrothermal period indicated that sulfur was most likely derived from sedimentary rock and magmatic sulfur sources. The Pb isotope data also implied a mixture of upper crust and mantle sources. Therefore, we propose that the Sipingshan gold deposit is a continental exhalative sedimentation-type gold deposit superimposed by later magmatic–hydrothermal fluids, and formed during the subduction of the Paleo-Pacific Plate during the Early Cretaceous.

The influence of Sb doping on the local structure and disorder in thermoelectric ZnO:Sb thin films

Thermoelectric transparent ZnO:Sb thin films were deposited by magnetron sputtering, with Sb content varying between 2 and 14 at%. As evidenced by X-ray diffraction analysis, the films crystallize in the ZnO wurtzite structure for lower levels of Sb-doping, developing a degree of amorphization for higher levels of Sb-doping. Temperature-dependent (10–300 K) X-ray absorption spectroscopy studies of the produced thin films were performed at the Zn and Sb K-edges to shed light on the influence of Sb doping on the local atomic structure and disorder in the ZnO:Sb thin films. The analysis of the Zn K-edge EXAFS spectra by the reverse Monte Carlo method allowed to extract detailed and accurate structural information in terms of the radial and bond angle distribution functions. The obtained results suggest that the introduction of antimony to the ZnO matrix promotes static disorder, which leads to partial amorphization with very small crystallites (∼3 nm) for large (12–14 at%) Sb content. Rutherford backscattering spectrometry (RBS) experiments enabled the determination of the in-depth atomic composition profiles of the films. The film composition at the surfaces determined by X-ray photoelectron spectroscopy (XPS) matches that of the bulk determined by RBS, except for higher Sb-doping in ZnO films, where the concentration of oxygen determined by XPS is smaller near the surface, possibly due to the formation of oxygen vacancies that lead to an increase in electrical conductivity. Traces of Sb–Sb metal bonds were found by XPS for the sample with the highest level of Sb-doping. Time-of-flight secondary ion mass spectrometry obtained an Sb/Zn ratio that follows that of the film bulk determined by RBS, although Sb is not always homogeneous, with samples with smaller Sb content (2 and 4 at% of Sb) showing a larger Sb content closer to the film/substrate interface. From the optical transmittance and reflectance curves, it was determined that the films with the lower amount of Sb doping have larger optical band-gaps, in the range of 2.9–3.2 eV, while the partially amorphous films with higher Sb content have smaller band-gaps in the range of 1.6–2.1 eV. Albeit the short-range crystalline order (∼3 nm), the film with 12 at% of Sb has the highest absolute Seebeck coefficient (∼56 μV/K) and a corresponding thermoelectric power factor of ∼0.2 μW·K−2·m−1.

Ultrafast Dynamics of the Topological Semimetal GdSbxTe2–x–δ in the Presence and Absence of a Charge Density Wave

Time-resolved dynamics in charge-density-wave materials have revealed interesting out-of-equilibrium electronic responses. However, these are typically only performed in a single material possessing a CDW. As such, it is challenging to separate subtle effects originating from the CDW. Here, we report on the ultrafast dynamics of the GdSbxTe2–x–δ series of materials where EF can be tuned, resulting in a change from an undistorted tetraganal phase to a CDW with a wavevector that depends on x. Using mid-infrared, near-infrared, and visible excitation, we find the dynamics are sensitive to both EF and the presence of the CDW. Specifically, as the Sb content of the compounds increases, transient spectral features shift to higher probe energies. In addition, we observe an enhanced lifetime and change in the sign of the transient signal upon removing the CDW with high Sb concentrations. Finally, we reveal fluence- and temperature-dependent photoinduced responses of the differential reflectivity, which provide evidence of transient charge density wave suppression in related telluride materials. Taken together our results provide a blueprint for future ultrafast studies of CDW systems.

Preliminary handheld XRF analysis of Late Bronze Age metal finds from the Budakeszi-Őzvölgy-tető site (Pest county, Hungary)

This study discusses the chemical analysis results of Middle and Late Bronze Age stray finds and the Late Bronze Age hoards excavated at the recently discovered Budakeszi-Őzvölgy-tető site (Pest County, Hungary). This measurement series is the second stage in the scientific evaluation of the finds, which helps to characterize the elemental composition and raw material characteristics of the A and B hoards and the stray finds. Our aim is to obtain elemental composition information on the 103 objects, which can be used to identify the main alloy types within the hoards, as well as to establish a research strategy for the further examination of the metal finds from the Őzvölgy-tető with more complex and reliable methods. A handheld XRF device was used, which provides compositional information on the surface of the objects, but its main advantage is that it enables the analysis of a large number of samples within a short time. Here, we interpret the obtained data within the limits of the applied method. Based on our results, the majority of the artifacts can be identified as Cu-Sn alloys. Pb, Sb, Ni, Zn, Ag, Fe, Co and As are the main accompanying elements of the objects’ patina from Budakeszi, their presence being indicative of the raw material and its source. The presence of certain elements at higher quantities may indicate specific technological phenomena. The high surface Pb content on the convex part of the ingots is probably due to the phenomenon of lead segregation. While the high Fe content could be interpreted as a technological defect and the result of an incomplete iron removal process during smelting. Handheld XRF measurements show a correlation between patina color and surface elemental composition in some cases (e.g., dark gray – high Pb, black – high Pb-Sb), but more typically, the same color can be associated with different elemental combinations (grayish-silver, high Pb-Sb, Pb-Sn, high Sn). Our results help to independently verify the relative dating of the hoards and the stray finds. The high Fe or Zn content, which is not typical of the Late Bronze Age, allows us to date some of the stray find lumps and one sheet of metal to the Medieval Period or Modern Ages. The high surface Sb and Pb contents observed in Late Bronze Age artifacts from Budakeszi are in good agreement with former quantitative elemental composition data from Transdanubian (e.g., Biatorbágy, Velem-Szent Vid), Austrian and Slovenian artifacts deposited in the Ha B1 period, which support the archaeological dating of the hoards and most stray finds.

Microstructure of an extraordinary Bronze Age copper ingot with a high antimony content

Abstract The Cu ingot from Velem contains approximately 10 wt.% Sb, 4.5 wt.% As, 1.2 wt.% S and Ag, as well as other trace elements in an amount below 0.2 percent by weight. A Cu2S band running virtually across the entire width of the ingot suggests that it was formed by the reaction of molten Cu with antimonite (Sb2S3). Remarkably, the generated cutting surface was not copper-colored but had a silvery appearance which, however, can be attributed to the high Sb content. The metallographic examinations revealed a very inhomogeneous structural composition of the ingot. Large areas consist of dendritically solidified Cu, while the interdendritic areas are characterized by mixtures of different phases of the elements Cu-Sb-As-S.

Genesis and prospecting significance of the Buziwannan gold-polymetallic ore deposit in the West Kunlun Orogen Belt, China: Constraints from mineral geochemistry and in situ S–Pb isotope analyses of sulfides

The Buziwannan gold-polymetallic deposit is located in Northwest China's West Kunlun Orogen Belt (WKOB). There are two metallogenic stages that have been identified: skarn and hydrothermal. In this research study, in situ mineral geochemistry and sulfur–lead isotopes are used to precisely constrain the genesis and ore-forming process.Pyrite is the most dominant sulfide, and four types have been identified. Py0 is a sedimentary euhedral crystal; Py1 is a subhedral grain occurring in skarn ores, and coexists with Po1, Apy1, Ccp1 and Gn1; Py2, which coexists with Apy2, Po2 and Ccp2, is a subhedral to irregular crystal; and Py3 is a colloform crystal. Gn2 is the most recent sulfide. Magnetite and Ccp1 LA–ICMPS analyses indicate a skarn origin. Py0 and Py1 have the highest Co/Ni ratios and Ni contents, respectively, and Au has positive correlations with Pb, Ag and As, according to the trace element compositions of pyrite (LA–ICPMS). With the exception of four spots, most pyrites have Au (0.01–30.23 ppm) and As (1.47–15,709 ppm) concentrations below the Au saturation line, indicating that the majority of gold is present as lattice bound Au+. Py3 has clearly higher Sb contents indicating that Sb-rich fluids were added.The δ34S values of sulfides show that the sedimentary Py0 and skarn sulfides have the highest and lowest δ34S values of +13.30 to +14.67 ‰ and +4.48 to +7.77 ‰, respectively, and other sulfides possess δ34S values that fall between the two members, indicating a mixed source of magmatic and sedimentary. The lead isotope values also indicate that the sulfides from the hydrothermal stage have a mixed Pb source of magmatic and sedimentary.The skarn ores are spatially and genetically related to the Triassic granodiorite, indicating a Triassic age for ore formation. The Triassic magmatic intrusions hold the potential for future gold deposit exploration in the WKOB.

Alleviation of metal stress in rape seedlings (Brassica napus L.) using the antimony-resistant plant growth-promoting rhizobacteria Cupriavidus sp. S-8-2

This study investigated an effective strategy for remediating antimony (Sb)-contaminated soil using the bacterial strain screened from Sb-contaminated fern rhizospheres due to its superior growth-promoting, heavy-metal(loid) resistant, and antibiotic-tolerant characteristics. The strain that belongs to Cupriavidus sp. was determined by 16S rRNA sequencing and showed no morphological changes when grown with high concentrations of Sb (608.8 mg/L). The strain showed prominent indole acetic acid (IAA), phosphate-solubilizing abilities, and ACC deaminase activity under Sb stress. Moreover, IAA and soluble phosphate levels increased in the presence of 608.8 mg/L Sb. Inoculation of rape seedlings with Cupriavidus sp. S-8-2 enhanced several morphological and biochemical growth features compared to untreated seedlings grown under Sb stress. Inoculation of Cupriavidus sp. S-8-2 increased root weight by more than four-fold for fresh weight and over two-fold for dry weight, despite high environmental Sb. The strain also reduced Sb-mediated oxidative stress and malondialdehyde contents by reducing Sb absorption, thus alleviating Sb-induced toxicity. Environmental Scanning Electron Microscope (ESEM) imaging and dilution plating technique revealed Cupriavidus sp. S-8-2 is localized on the surface of roots. Identifying the Sb-resistant plant growth-promoting bacterium suggested its usefulness in the remediation of contaminated agricultural soil and for the promotion of crop growth. We highly recommend the strain for further implementation in field experiments.

Evaluation of antimony availability in a mining context: Impact for the environment, and for mineral exploration and exploitation.

This work aims to establish Sb mobility, its transfer to biota and its effect on soil health in a semi-arid climate. The results show the presence of stibnite (Sb2S3) as the main primary Sb compound, bindhemite (Pb2Sb2O6(O,OH)), and minor proportions of stibiconite (Sb3+(Sb5+)2O6(OH)) as oxidised Sb species. This research also observes very high total Sb contents in mining materials (max: 20,000 mg kg−1) and soils (400–3000 mg kg−1), with physical dispersion around mining materials restricted to 450 m. The soil-to-plant transfer is very low, (bioaccumulation factor: 0.0002–0.1520). Most Sb remains in a residual fraction (99.9%), a very low fraction is bound to Fe and Mn oxy-hydroxides or organic matter, and a negligible proportion of Sb is leachable. The higher Sb mobility rates has been found under oxidising conditions with a long contact time between solids and water. The main factors that explain the poor Sb mobility and dispersion in the mining area are the low annual rainfall rates that slow down the Sb mobilisation process and the scarce formation of oxidised Sb compounds. All these data suggest poor Sb (III) formation and a low toxicological risk in the area associated with past mining activities. The low mobility of Sb suggests advantages for future sustainable mining of such ore deposits in a semi-arid climate and is also indicative of the limitations of geochemical exploration in the search for new Sb deposits.

Trace element compositions of galena in an MVT deposit from the Sichuan-Yunnan-Guizhou metallogenic province, SW China: Constraints from LA-ICP-MS spot analysis and elemental mapping

Galena trace element signatures and element partitioning between associated sulfides are poorly constrained, especially in Mississippi Valley-type (MVT) Zn-Pb deposits. This study reports laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) spot analysis data of different stages of galena as well as elemental mapping results of typical sulfide assemblages in the Daliangzi Zn-Pb deposit, one of the largest MVT deposits in the Sichuan-Yunnan-Guizhou (SYG) metallogenic province, SW China. The galena is generally enriched in Sb and Ag, with minor Cd, Cu, and As, but depleted in Bi. Antimony was generally incorporated into galena lattice via Sb3+ + Ag+ ↔ 2Pb2+, and the substitution of 2Sb3+ + □ (vacancy) ↔ 3Pb2+ also occurred at high Sb content level (>1200 ppm). Direct substitution is the main way for Cd incorporation, while Cu and As may exist via coupled substitution. Micro-inclusions also play important roles in the incorporation of Sb, As, and Cu in some cases. The elemental distribution maps show that Sb, Ag, and Tl are dominantly incorporated into galena, while Cd, Fe, Mn, Cu, As, Ga, and Ge are primarily concentrated in sphalerite. However, when present tennantite-tetrahedrite will become the preferential host phase of Sb, Ag, Cu, and As. This elemental partitioning verifies that the preferential host sulfide for trace elements is controlled by intrinsic factors (e.g., oxidation state and ion radius) rather than external factors (e.g., metal sources, pressure, temperature, and redox conditions). External factors, such as temperature, may be vital for the partitioning of a given element (e.g., Cd) between priority and subordinate hosts. Additionally, the galena trace element characteristics are found to vary significantly with the ore genetic types, which appears to imply the applicability of galena geochemistry in the ore type discrimination.

In-situ trace element and S isotope compositions of sulfides from the Tonggou Cu deposit, Eastern Tianshan Orogen: Implication for ore-forming process

The Tonggou deposit is located in the western Bogda Orogen, the northern margin of Eastern Tianshan. Porphyry Cu and vein-type Cu-Zn mineralization are both developed in the Tonggou orefield. This well-preserved porphyry-vein system, therefore offers an excellent opportunity to evaluate the genetic relationship and ore-forming process between porphyry Cu and vein-type Cu-Zn mineralization. Porphyry mineralization consists of magnetite-quartz (P1) and chalcopyrite-quartz (P2) stages, whilst vein-type mineralization includes pyrite-quartz (V1), polymetallic sulfide-quartz (V2), and pyrite-calcite (V3) stages. Four pyrite generations are identified, including porphyry Cu ore-related (Py1) and vein-type Cu-Zn ore-related (Py2, Py3, and Py4) ones. In most cases, Py1 (stage P2) occurs as anhedral grains, Py2 (stage V1) as fine anhedral grains, Py3 (stage V2) as euhedral-subhedral grains, and Py4 (stage V3) as anhedral aggregates. The Sb content first decreases from Py1 to Py2, then increases from Py2 to Py3, and finally decreases from Py3 to Py4. Cobalt and Ni contents show opposite trend to that of Sb. The relatively high Sb but low Co-Ni contents in Py1 and Py3 indicate that the main ore stage (P2 and V2) environment was high oxygen fugacity and low sulfur fugacity. Moreover, the contents of Cu (Py1: avg. 4108 ppm, Py2: avg. 735 ppm, Py3: avg. 284 ppm, Py4: avg. 149 ppm) and Ag (Py1: avg. 204 ppm, Py2: avg. 11.1 ppm, Py3: avg. 6.29 ppm, Py4: avg. 2.98 ppm) gradually decrease from Py1 to Py4, indicating that the initial ore fluid was Cu-Ag rich. The δ34S values obtained are 4.6–6.8 ‰ (avg. 5.9 ‰; Py2), 5.7–7.4 ‰ (avg. 6.6 ‰; Py3), and 7.3–8.8 ‰ (avg. 8.1 ‰; Py4), which indicate that the sulfur of vein-type mineralization was initially derived from felsic magma, and subsequently mixed with strata sulfur. Furthermore, the similar δ34S range of Ccp1 (4.7–5.3 ‰) from porphyry ore and Ccp2 (3.3–4.8 ‰) from vein-type ore indicates that they have a similar felsic-magma-derived sulfur source. Combining with principal component analysis (PCA) of pyrite trace elements and REE patterns, the different pyrite generations can be divided into porphyry pyrite and vein-type pyrite, albeit with similar fluid source.Consequently, we suggest that the Tonggou porphyry and vein-type ores have similar ore-fluid source, and may belong to the same porphyry mineralization system with different ore-forming processes. Redox change may have played an important role in the metal enrichment and precipitation at Tonggou.

Complex fluid source of the multistage pyrite-bearing Huilvshan gold deposit (west Junggar, NW China): Insight from pyrite texture, sulfur isotope and trace element compositions

Hydrothermal gold deposits commonly form during protracted multistage ore-forming processes, however, discriminating among different ore-forming fluids and tracing their origin to unique or different repositories is a challenging task. The Huilvshan gold deposit in West Junggar (Xinjiang province, NW China), was affected by three hydrothermal stages and thus provides an opportunity to examine complex ore-forming processes. The deposit consists of gold-bearing quartz-sulfide veins and disseminated sulfides, hosted within Early Carboniferous basalts and tuffs. Three stages of hydrothermal pyrite (Py1, Py2, and Py3) were identified. Gold is only present in Py2 where it occurs as native gold inclusion and in invisible form. Anhedral Py1, disseminated in the altered basalt, is characterized by higher Ni (13.7 to 635 ppm) concentrations than Py2 and Py3. Euhedral-subhedral Py2 is the richest in Au (1.46 to 25.7 ppm) among three stages of pyrite. Py3 is subdivided into grains with zonal texture (Py3a) and irregular grains (Py3b). Both sub-types have high Sb (56.8 to 1599 ppm) and Tl (0.02 to 68.7 ppm) concentrations. In situ δ34S values of Py1 (-6.0 to 2.7 ‰) are similar to those of Py2 (-5.9 to 3.9 ‰), whereas Py3 has extremely negative δ34S values (-44.3 to-18.0 ‰).Ar-Ar ages of hydrothermal muscovite coexisting with Py2 indicate that the Huilvshan gold deposit formed at ∼300 Ma. The sulfur isotopic systematics of Py1 and Py2, close spatial and temporal relationship between the Huilvshan gold deposit and adjacent felsic intrusions, and paucity of regional metamorphic rocks in the region all suggest that hydrothermal fluids in stage I (Py1) and II (Py2) were derived from magmatism. On the other hand, stage III pyrite and associated sulfides more likely precipitated from a hydrothermal fluid that circulated in tuffs, based on the extremely negative δ34S values of Py3, similar to those measured from framboidal pyrite in the host tuffs.Therefore, textural, trace elemental and sulfur isotope data from pyrite suggest different sources for the hydrothermal fluids in the Huilvshan gold deposit, and that magmatic activity may have contributed the most to the main ore-forming stage. The genesis of this Huilvshan gold deposit could provide significant insights into the origin of other hydrothermal gold deposits that show multiple sulfide generations.

Antimony in Mine Wastes: Geochemistry, Mineralogy, and Microbiology

AbstractAntimony (Sb) is a valuable mined commodity, used mostly in fire retardants, and considered a critical element. It is also a potential environment hazard classed as a carcinogen. Antimony is concentrated in tailings and waste rock from Sb mines as well as other locations, such as precious metal deposits, where Sb is present in the ore but not recovered. This review covers the aqueous geochemistry, isotope chemistry, mineralogy, and microbiology of Sb in the context of mine waste. The primary minerals stibnite and sulfosalts may release Sb in surface and groundwaters and result in contamination of soils, plants, and river sediments. In some cases, Sb mobility is limited by its adsorption and incorporation into Fe (oxyhydr)oxides. At higher Sb concentrations, precipitation of Sb secondary hosts such as tripuhyite (FeSbO4, relatively insoluble) and brandholzite (Mg[Sb(OH)6]2 · 6H2O, highly soluble) influence Sb concentrations in water associated with mine waste. Although Sb is nonessential to organisms, microorganisms are involved in oxidation, reduction, and methylation processes that can drive biogeochemical transformations. Limited toxicological information about Sb makes it challenging to establish regulations or guidelines limiting the concentration of Sb. Antimony is frequently associated with arsenic in mine waste, and remediation design is often based on the assumption that both metalloids behave in a similar way. However, new research suggests that in some environments, this is not the case, and Sb should be considered based on its unique biogeochemical behavior.

Rhizosphere Microbial Communities and Geochemical Constraining Mechanism of Antimony Mine Waste-Adapted Plants in Southwestern China.

Antimony (Sb) and arsenic (As) are two hazardous metalloid elements, and the biogeochemical cycle of Sb and As can be better understood by studying plant rhizosphere microorganisms associated with Sb mine waste. In the current study, samples of three types of mine waste—Sb mine tailing, waste rocks, and smelting slag—and associated rhizosphere microorganisms of adapted plants were collected from Qinglong Sb mine, southwest China. 16S rRNA was sequenced and used to study the composition of the mine waste microbial community. The most abundant phylum in all samples was Proteobacteria, followed by Bacteroidota, Acidobacteriota, and Actinobacteriota. The community composition varied among different mine waste types. Gammaproteobacteria was the most abundant microorganism in tailings, Actinobacteria was mainly distributed in waste rock, and Saccharimonadia, Acidobacteriae, and Ktedonobacteria were mainly present in slag. At the family level, the vast majority of Hydrogenophilaceae were found in tailings, Ktedonobacteraceae, Chthoniobacteraceae, and Acidobacteriaceae (Subgroup 1) were mostly found in slag, and Pseudomonadaceae and Micrococcaceae were mainly found in waste rock. Actinobacteriota and Arthrobacter are important taxa for reducing heavy metal(loid) mobility, vegetation restoration, and self-sustaining ecosystem construction on antimony mine waste. The high concentrations of Sb and As reduce microbial diversity.

Diversity and composition of soil bacteria between abandoned and selective-farming farmlands in an antimony mining area.

Background and aimsLand abandonment and selective farming are two common management methods to restore the soil conditions of low-pollution farmland in mining areas. The soil bacterial community plays an important role in farmland soil restoration; however, few studies have compared the composition and diversity of soil bacteria between the abandoned farmlands (AFS) and selective-farming farmlands (FFS). Here, the effects of AFS and FFS on soil properties and bacterial diversity were evaluated in an antimony (Sb) mining area in southern China. This study aimed to identify effective land management methods in terms of positive or negative changes in soil environment and bacterial diversity.Methods16S rRNA high-throughput sequencing was used to compare the diversity and composition of soil bacteria between AFS and FFS in the Xikuangshan (the largest Sb mine in the world).ResultsCompared to AFS, FFS had higher Sb concentration and nutritional properties (e.g., available N, P, and K) and lower Zn concentration (p < 0.05). The bacterial alpha diversity including Chao1 index, Simpson index, Shannon index and Pielou−e index in FFS was higher than AFS (p < 0.05). At the phylum level, FFS had higher relative abundances of Chloroflexi, Acidobacteria, Gemmatimonadetes, and Rokubacteria, and lower relative abundances of Firmicutes, Actinobacteria, and Bacteroidetes. At the genus level, FFS had higher relative abundances of Acidothermus, Haliangium, and Rokubacteriales, and lower relative abundances of Bacillus, Rhodococcus, Sphingomonas, and 67-14. Redundancy analysis indicated that soil heavy metal content and soil fertility were closely correlated with the soil bacterial community. Altogether, selective farming of low-pollution farmland in the mining area can improve soil properties and soil bacterial diversity.

Crystallization Of Tensile Strained n-Type Ge By Continuous Wave Laser Annealing

In recent years, germanium (Ge) has attracted a lot of attention for the development of next generation devices due to its higher carrier mobilities compared with silicon (Si) and its compatibility for complementary metal-oxide-semiconductor (CMOS) applications. It is widely known that Ge is an indirect-band semiconductor like Si. However, by introducing tensile strain, the 136 meV difference between direct and indirect gaps can be reduced. Furthermore, in the case of 0.2-0.3% tensile strained Ge, n-type doping in the order of 1019 cm-3 were expected to be resulted in quasi direct-band light emission around 1550 nm wavelength. [1] The realization of this tensile strained n-Ge is promising for the integration of light sources on next generation Ge-based devices. Here, we focused on n-type Ge deposition using molecular beam epitaxy (MBE) method and have succeeded in realizing highly Sb-doped epitaxial n-Ge films by modulating the deposition temperatures. [2] Moreover, we have recently reported the crystallization of amorphous Ge by high-speed continuous wave laser annealing (CWLA), which more importantly also resulted in the introduction of 0.55-0.62% tensile strain. [3] In this study, we applied the similar annealing technique for crystallization of Sb-doped Ge toward the realization of tensile strained n-type Ge films.Sb-doped poly-crystalline Ge films with high Sb concentration (approximately 1019 cm-3) and thickness of about 100 nm were deposited on quartz substrate by molecular beam deposition at 450ºC substrate temperature. Then, 300 nm of SiO2 capping layer was deposited by sputtering in room temperature, such that the sample structure become that shown in Fig.1(a). The samples then annealed in the CWLA system equipped with Nd:YVO4 solid state laser with wavelength of 532 nm as the light source, which scan laser light at the speed (vscan) of 800 m/min. Also, the laser is focused to 20 μm diameter and shifted at 5 μm to scan the samples. Here, the laser power (Elaser) was changed from 300 to 1000 mW. After laser annealing, the capping layer were removed then the samples were characterized by micro-Raman spectroscopy.The annealed sample surface shows brighter contrast compared to the as-deposited samples, as shown in Fig.1(b) and (c), which indicate the structural change of Ge layer. Raman spectra measured at surface of annealed Ge layers are summarized in Fig.2. Here, Ge-Ge peak around 300.2 cm-1 confirmed on the samples, indicating the crystallization of the Ge layers. This peak is not shifted in low Elaser but largely shifted in high Elaser at up to -2.4 cm-1 for undoped and -3.6 cm-1 for the Sb-doped Ge films. This difference could be explained by the liquid phase recrystallization after Ge layer melted in high Elaser (≥600 mW). During recrystallization process, tensile strain is accumulated upon cooling as the tensile strain amount (0.43-0.63%) is agree with the thermal expansion value of Ge between solidification temperature and room temperature (-0.60%). This mechanism is similar to the crystallization of amorphous Ge films on quartz substrates in our previous work. [3] These results show the successful crystallization of tensile strained n-Ge layer by the CWLA method. This finding will be useful for the growth of Ge-based films and a promising step toward the development of CMOS-integrated optoelectronics. Further investigation of the annealing conditions and its relations with the properties of Sb-doped Ge films will be discussed in the main presentation. References Liu, J., Kimerling, L. C. & Michel, J. Semicond. Sci. Technol. 27, (2012).Saputro, R.H., Matsumura, R. & Fukata, N. Cryst. Growth & Des. 21, 6523–6528 (2021).Matsumura, R. & Fukata, N. ECS J. Solid State Sci. Technol. 9, 063002 (2020). Figure 1

Influence of soil physicochemical properties, particle size fractions and mineralogy on the leaching potentials of arsenic and antimony in abandoned mine soils

At abandoned mine sites, arsenic (As)- and antimony (Sb)-enriched soils are often disposed of through onsite burial or capping. In highly weathered mine sites, the mobility of As and Sb is typically controlled by iron (Fe)(III)/Fe(II) phases; thus, the suitability of such disposal methods and appropriate testing techniques are questionable. In the present study, leaching potentials of As and Sb were examined using the toxicity characteristic leaching procedure (TCLP), waste extraction test (WET), and WET-extended procedure (WET-EXT) at three abandoned mine site soils in Australia. The leached concentration of As regularly exceeded USEPA criteria (5 mg L−1). The highest leached concentrations of As and Sb were observed in the finest particle size fraction (< 0.053 mm) by WET-EXT (1 040 mg L−1 for As and 21.10 mg L−1 for Sb) followed by WET (800 mg L−1 for As and 20.90 mg L−1 for Sb). The TCLP method resulted in the lowest concentrations of leached As (0.000 9 mg L−1) and Sb (0.000 3 mg L−1). Crystalline and amorphous As-bearing Fe oxides were the main phases in the soils studied. However, the best correlations of leached As determined by TCLP (0.832), WET (0.944), and WET-EXT (0.961) were found with the non-specifically sorbed (NS1) As fraction. The mineralogical and sequential extraction data clearly indicate the dominant role of Fe geochemistry in controlling leachability of As and Sb. The TCLP method was unlikely to be suitable for assessing leachability, as it exhibited no relationship with leachable Fe and substantially lower leached As and Sb than the other two methods. Given the high to extremely high leachable As and Sb concentrations, most of the soil samples would not be recommended for placement in capping works, old shafts, or reduction systems (e.g., collection in drainage basins).