Antimony Mine Research Articles

Heavy metal pollution characteristics and potential ecological risk assessment of soils around three typical antimony mining areas and watersheds in China

China is the largest antimony resource globally. The mining and smelting of antimony will inevitably have a significant impact on the surrounding and downstream farmlands of the mining area, Therefore, it is necessary to understand the pollution characteristics of antimony and evaluate its potential environmental risks. In this paper, three typical antimony mining areas were used as research districts to analyze the contents of heavy metals in soils of the mining areas and watersheds. The single-factor pollution index method, Nemerow comprehensive pollution index method, geo-accumulation index method, and potential ecological risk index method were used to comprehensively evaluate the pollution status and ecological risk of heavy metals in soils around the mining areas. The soil around the Lengshuijiang tin mine was polluted by As, Cd, Zn, and Sb, it was a heavily polluted soil and at a high ecological risk level. The arable soil around the Nandan tea mountain antimony mine was polluted by As, Cd, Cu, Pb, Sb, and Zn, and it was a heavily polluted soil with very high ecological risk level. The soil around the Xunyang antimony mine was mainly polluted by Sb and it was a moderately polluted soil with moderate ecological risk level. The results revealed that the overall soil heavy metal levels in the Lengshuijiang mining area and the Nandan mining area were in a high-risk state, most likely due to the mining and smelting of metal ores and the weathering of mineralised rocks. showing a high-potential ecological risk in these mining areas. We expect to provide a scientific basis for the safe utilization of farmland and pollution control around the antimony mining areas and watersheds in China.

Attenuation of antimony in groundwater from the Xikuangshan antimony mine, China: Evidence from sulfur and molybdenum isotope study

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 SO42−, 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.

Pollution and risk assessment of heavy metals in rivers in the antimony capital of Xikuangshan

Xikuangshan (XKS) is the world's largest antimony mining region, and its exploitation for hundreds of years has also resulted in serious soil erosion, fragile ecology, contaminated water, and shortage water. Through systematic and scientific collection samples from the rivers in XKS, the Nemerow index (NI), modified heavy metal pollution index (m-HPI), ecological risk index, and health risk indexeswere used to evaluate and analyze the water quality, pollution levels and risks of heavy metals (Sb, As, Mn, Pb, Zn, Hg, Cd) to ecology and humans in XKS. The results showed that the average concentrations of TN, TP, Sb, As and Hg in surface water were 0.48 mg/L (0–4.34 mg/L), 2.58 mg/L (0–4.34 mg/L), 1.05 mg/L (0.0009–5.33 mg/L), 1.06 mg/L (BDL–19.60 mg/L) and 0.00084 mg/L (LDBL–0.0036 mg/L), respectively, exceeding the limits of the Chinese surface water quality standards. Based on the m-HPI method, only 8.57% of the sampling points are classified as the worst water quality. However, according to the NI method, about 7.14% and 87.16% of the sampling points in the study area are moderately and severely polluted, respectively. The results of heavy metal pollution based on the NI evaluation is were more serious than that on the m-HPI method. The values of ecological risk assessment varied from 22.69 to 7351.20, revealed that heavy metals pose a very serious risk to the surface water ecosystem at more than 50% of the sampling sites, and Sb and As are the main pollutants, followed by Hg. The total non-carcinogenic risk index (TCR) for adults and children were 47.70 and 90.10 respectively, Sb and As is the main non-carcinogenic risk factor. For adults and children, the average carcinogenic risk (CR) of As was 6.49 × 10–3 and 1.05 × 10–2, respectively, and exceeded the threshold of 1 × 10–4, indicating a high carcinogenic risk.

A novel vacuum distillation method for preparing high purity antimony trisulfide from antimony minerals

High purity antimony trisulfide has been widely used in the photovoltaic field. A new clean process for preparing high purity antimony trisulfide directly from antimony ore by a two-step vacuum distillation method at low temperature was proposed in this study. Impurity arsenic was volatilized into the gas phase, and antimony and other impurities were retained in the residue in the first step at 773 K and 5 Pa for 60 min in the first step vacuum distillation. The content of the arsenic in the residue was 0.1 × 10-3 wt%, and the removal ratio was 99.98 %. Antimony trisulfide was volatilized into the gas phase, and other impurities were retained in the residue in the second step vacuum distillation at 923 K and 5 Pa for 30 min. The total removal ratio of impurities through the two-step process can reach 99.524 %, and the antimony trisulfide product with a purity of about 99.99 wt% can be obtained directly. This method provides a novel idea for the efficient and low-cost preparation of high-purity antimony trisulfide.

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.

Response of soil microbial activities and ammonia oxidation potential to environmental factors in a typical antimony mining area

Mining, smelting and tailing deposition activities can cause metal(loid) contamination in surrounding soils, threatening ecosystems and human health. Microbial indicators are sensitive to environmental factors and have a crucial role in soil ecological risk assessment. Xikuangshan, the largest active antimony (Sb) mine in the world, was taken as the research area. The soil properties, metal(loid) contents and microbial characteristics were investigated and their internal response relationships were explored by multivariate statistical analysis. The assessment of the single pollution index and Nemerow synthetic pollution index (PN) showed that the soils were mainly polluted by Sb, followed by Cd and As, in which sampling site S1 had a slight metal(loid) pollution and the other sampling sites suffered from severe synthetic metal(loid) pollution. The microbial characteristics were dissimilar among sampling points at different locations from the mining area according to hierarchical cluster analysis. The correlation analysis indicated that fluorescein diacetate hydrolase, acid phosphatase, soil basal respiration and microbial biomass carbon were negatively correlated with PN, indicating their sensitivity to combined metal(loid) contamination; that dehydrogenase was positively correlated with pH; and that urease, potential ammonia oxidation and abundance of ammonia-oxidizing bacteria and archaea were correlated with N (nitrogen) contents. However, β-glucosidase activity had no significant correlations with physicochemical properties and metal(loid) contents. Principal components analysis suggested bioavailable Sb and pH were the dominant factors of soil environment in Xikuangshan Sb mining area. Our results can provide a theoretical basis for ecological risk assessment of contaminated soil.

Morphological Distribution and Formation Mechanisms of Antimony in the Shallow Groundwater of the Xikuangshan Antimony Mine in Hunan, China

The century-old mining development and utilization of antimony (Sb) ore in Xikuangshan (XKS) mine, groundwater antimony pollution has attracted great attention. At present, the sources and geochemical behaviors of high Sb groundwater in this area have been widely recognized, but morphological distribution and formation mechanisms of Sb(V) and Sb(III) in shallow groundwater were still little known. Forty-three groundwater samples of Magunao aquifer (D3x4) were collected between June and September 2020 to determine morphological distribution and formation mechanisms of Sb valence state in the recharge area, runoff area and discharge area. The range of Sb content in the recharge area, runoff area, and discharge area of the D3x4 water was 3.300 × 10−3–7.982 mg/L, 1.760 × 10−2–17.326 mg/L and 1.230 × 10−2–16.773 mg/L, respectively. The D3x4 water is dominated by Sb(V), which form was Sb(OH)6−. The Sb(V) mainly comes from the oxidative dissolution of Sb2S3, the mining activities, and the leaching of arsenic alkali residues. The silicate mineral weathering, carbonate mineral dissolution, and ion exchange promote the dissolution of Sb2S3. At the same time, redox and competitive adsorption in the runoff area increase the Sb(V) content in the water environment. The results of this research provide an understanding of the mechanism of Sb pollution in shallow groundwater and will help in controlling water-environment pollution and securing water-resource in mining areas.

Золотое оруденение Нижне-Мякитского рудно-россыпного узла (Северо-Восток России)

A comprehensive study of native gold and ore mineral parageneses of the Berental intrusive-dome structure in the southeastern part of the Yano-Kolyma gold-bearing belt has been carried out. The zonality of mineralization is shown: from the central part (in the Berental stock endocontacts) with the Au-Bi-Te mineralization "style" to - As-Au (in the exocontacts of the stock) and, further, to Ag-Pb-Zn on the periphery. In the same direction changes the fineness of native gold in ores, from high and medium to low fineness. Antimony mineralization was noted at the final stage of ore formation. Vertical zoning is expressed in the silver-polysulfide type of mineralization changing with depth to sulfide-sulfoarsenide and, lower, bismuth-sulfotelluride. A rare mineral, maldonite (Au2Bi), is relatively widespread. The end-to-end ore minerals are pyrrhotite, native bismuth, and its tellurides. The obtained facts permitted to attribute the hydrothermal system of the Berental stock to the RIRGD type, i. e. to gold deposits associated with restored intrusives, which can contribute to the improvement of the methodology for prospecting and evaluation works at deposits of this type and to the discovery of large occurrences in terms of reserves.

Stable sulfur and oxygen isotopes of sulfate as tracers of antimony and arsenic pollution sources related to antimony mine activities in an impacted river

Source identification of antimony (Sb) and arsenic (As) pollution associated with mine activities is crucial for pollution prevention and control, but is still challenging. A typical river at the Xikuangshan antimony mine affected by known mine activities along the runoff, including mining, beneficiation and smelting, may allow to test the possibility and reliability of stable isotopes of sulfate (δ34SSO4 and δ18OSO4) as tracers to identify Sb and As sources associated with mine activities. The river water and mine wastewater samples were chemically and isotopically characterized in the dry and rainy season respectively. As expected, the concentrations of Sb, As and SO42− in the river increased and varied with the seasons. The spatial and seasonal variations of Sb, As and SO42− concentrations in the river were consistent with the mixing of the mine wastewater discharged into the river. Moreover, the impact of mine activities resulted in the correlations of Sb, As and SO42− of the river water high in the rainy season but low in the dry season. The sulfur and oxygen isotopic compositions of SO42− of the river fell within the range composed of upstream river and its received mine wastewater. The estimated proportional contributions of multiple mine activities to the river by a Bayesian isotope mixing model suggested that the total contribution of the mine activities ranged from 37 ± 10% to 96 ± 4% in the dry season and from 28 ± 8% to 88 ± 8% in the rainy season. The leachate of waste rocks and smelting slag dumps was the predominant contributor in the upper section, with the proportions greater in the dry season (37 ± 9%∼76 ± 12%) than in the rainy season (28 ± 8%∼56 ± 9%). The mining drainage became the primary source (69 ± 8%∼80 ± 8%) in the lower section in the dry season, whereas all sources contributed approximately equally in the rainy season. Leakage from the tailings pond (19 ± 13%) is another important source in the rainy season. This study demonstrated that sulfur and oxygen isotopes can be effective for source identification and qualification of multiple mine activities on Sb and As pollution in the river, which provides new insights into source apportionment of metal(loid)s pollution related to complex mine activities.

U-Pb Scheelite Ages of Tungsten and Antimony Mineralization in the Stibnite-Yellow Pine District, Central Idaho

Abstract The Stibnite-Yellow Pine district contains the largest antimony resource in the United States, as well as significant gold, and is a historic producer of tungsten. Application of in situ laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) direct dating of scheelite from two Au-Sb-W ore deposits, Yellow Pine and Hangar Flats, yielded an older group of U-Pb ages in the range of 60.0 ± 2.8 to 57.0 ± 1.1 Ma and a younger U-Pb age for scheelite intergrown with stibnite of 47.4 ± 1.1 Ma. These in situ analyses were calibrated by isotope dilution-thermal ionization mass spectrometry (ID-TIMS) U-Pb lower intercept ages of two coarsely crystalline scheelite samples that yielded ages of 57.52 ± 0.22 and 56.62 ± 0.16 Ma. Scheelite of the latter age is of sufficient quality to serve as a primary reference material for LA-ICP-MS scheelite U-Pb geochronology. The group of older U-Pb scheelite ages agrees with 40Ar/39Ar ages of 56.9 ± 1.2 to 56.38 ± 0.54 Ma on adularia from Yellow Pine and Hangar Flats, whereas the younger U-Pb scheelite age is similar to an 40Ar/39Ar age of 46.00 ± 0.40 Ma on adularia from an epithermal gold-silver deposit in the adjacent Thunder Mountain caldera. Our results indicate that the main stage of tungsten mineralization occurred at ca. 57 Ma, whereas the main stage of antimony mineralization occurred at ca. 47 Ma—thereby providing first-time age constraints for antimony and tungsten mineralization in the Stibnite-Yellow Pine district.

The Arsenic-Antimony Creek at Sauerbrunn/Burgenland, Austria: A Toxic Habitat for Amphibians.

(1) Background: All Austrian amphibians are affected by the degradation of habitats. Mining contributes to habitat destruction by the formation of spoil heaps and mine drainage waters. In Stadtschlaining/Burgenland, antimony mining led to increased arsenic (As) and antimony (Sb) concentrations in soil and water. This study investigates a contaminated creek, still inhabited by amphibians. (2) Methods: Water and soil were analyzed along the creek and correlated with the occurrence of amphibians. (3) Results: As and Sb were increased, with up to 49,000 mg/kg As and 2446 mg/kg Sb in the soil. Up to 317 mg/kg As and 156 mg/kg Sb became bioavailable under gastric, and up to 298 mg/kg As and 30 mg/kg Sb under intestinal conditions, and were absorbed upon ingestion of soil. Larvae of Salamandra salamandra were found throughout the creek; survival rates were low. Rana temporaria occurs in the most contaminated sections but does not propagate here. Bombina variegata appears occasionally. Amphibians seem not to be able to detect and avoid metal or metalloid contamination. (4) Conclusion: Survival of larvae is dubious, but adult amphibians survive without apparent damage under severe metalloid contamination.

Assessment of rhizosphere bacterial diversity and composition in a metal hyperaccumulator (Boehmeria nivea) and a nonaccumulator (Artemisia annua) in an antimony mine.

Heavy metal hyperaccumulators are widely used in mining restoration due to their ability to accumulate and transport heavy metals, compared to nonaccumulators. Rhizosphere bacteria in metal hyperaccumulators play a key role in the uptake of heavy metals from soil; however, assessments of the differences of rhizosphere bacteria between metal hyperaccumulators and nonaccumulator are scarce. To understand the difference of bacterial composition between hyperaccumulator and nonaccumulator in rhizosphere, the diversity and composition of rhizosphere bacteria in a metal hyperaccumulator (Boehmeria nivea) and a nonaccumulator (Artemisia annua) grown in the same field in Xikuangshan were evaluated using Illumina Miseq high-throughput sequencing technology. Boehmeria nivea and A. annua had 3926 overlapping OTUs, 19,736 and 17,579 unique OTUs, respectively. Boehmeria nivea had lower Chao1 index, Shannon index and Pielou index than A. annua. The dominant phyla and genera of rhizosphere bacteria in B. nivea and A. annua were similar, but some rhizosphere bacterial communities with heavy metal remediation ability mainly appeared in the rhizosphere of the hyperaccumulator. Compared to A. annua, B. nivea showed a significantly higher relative abundance of rhizosphere bacteria, such as Acidobacteria and Bacteroidete at the phylum level and RB41 at the genus level. Some specific rhizosphere bacteria with the ability to bind metal, such as Leifsonia and Kibdelosporangium, were only found in the rhizosphere of B. nivea. Results indicated that B. nivea, as a metal hyperaccumulator, has a key function in governing metal-resistant rhizosphere bacteria in response to antimony compound pollution stress. Understanding the diversity of rhizosphere bacteria between hyperaccumulators and nonaccumulators is beneficial to formulate strategies to improve metal uptake efficiency by selecting specific plant species and rhizosphere bacteria grown on polluted soil.

Specific development features of secondary gold mineralization in mature tailings of gold processing plants

The paper studies the development of secondary gold mineralization driven by the interaction of gold-bearing solutions with primary minerals in sulfide and oxidized ore processing tailings, as well as with secondary limonite formed during their long-term storage. Lowtemperature gas adsorption was used to establish that such tailings are characterized by high specific surface areas of up to 20 m2/g. Material surface area may play an important role in the processes of sorption and reduction. Using X-ray photoelectron spectroscopy, it has been established that secondary mineralization gold predominantly occurs in its elemental form, with a subordinate amount of the occluded ionic form of Au(I). It has been shown that Au(III) ions selectively precipitate from solutions at 25 &deg;C and pH 6.9&ndash;7.3 on pyrite, arsenopyrite, and limonite, forming individual metal particles of 30&ndash;1000 nm, as well as mineral aggregates of complex structure and composition, including oxidized antimony minerals, limonite, and nanodispersed gold. Gold precipitation on a mixture of hydrates of iron and manganese oxides was found in samples of oxidized ore processing tailings. The specific morphology and grain-size distribution of secondary gold particles on various carrier minerals and the composition of new formations have been studied. On the secondary limonite, containing calcite (up to 10 wt%) and quartz impurities, the gold particles are up to 500 nm and are uniformly distributed over the entire material surface. This is in contrast to the sulfide and oxidized ore processing tailings, where gold was selectively reduced on certain minerals. The paper considers the potential mechanisms of gold reduction on the surfaces of oxidized minerals.The work patially was carried out within the framework of the state&nbsp;assignment of the Institute of Chemistry and Chemical Technology&nbsp;of the Siberian Branch of the Russian Academy of Sciences (project&nbsp;No. 0287-2021-0014) using the equipment of the Federal Research&nbsp;Center &laquo;Krasnoyarsk Science Center of the Siberian Branch of the&nbsp;Russian Academy of Sciences&raquo;.

Characteristics of Antimony Migration and Transformation and Pollution Evaluation in a Soil-Crop System Around a Tin Mine in Hunan Province

This study used 193 sets of farmland soil and agricultural product samples collected from around a tin mine in Hunan Province, China, to explore the antimony (Sb) content characteristics and pollution status of soil and agricultural products and to provide a scientific basis for the prevention and control of soil antimony pollution in antimony mining areas and the safe use of farmland. We analyzed the amount of antimony in the soil, basic physical and chemical properties, and antimony content in agricultural products; studied the characteristics of antimony migration and transformation in the soil-agricultural product system; and conducted safety assessments on soil and agricultural products. The results showed that the soil ω(Sb) in the central area of the mine, the southern area of the mine, the central township area, the urban-rural transfer area, and the northern area of the mine reached (2348±2165), (1298±884.1), (311.8±526.5), (302.5±355.9), and (215.6±183.2) mg·kg-1, and the exceeding multiples reached 65.22, 36.06, 8.66, 8.40, and 5.99 times, respectively. The antimony enrichment coefficients of lettuce, scallion, cabbage, water spinach, garlic, and pea seedlings in agricultural products were 0.01-0.1, which indicated good antimony absorption capacity. The antimony enrichment coefficients of loofah, asparagus lettuce, pepper, carrot, bitter gourd, corn, eggplant, cowpea, and celery were less than 0.01, and the antimony absorption capacity was relatively poor. The safety assessment results showed that roots, allium, and garlic vegetables had a high risk of antimony pollution; leafy vegetables and legumes had a higher risk of antimony pollution; and solanaceous vegetables, melons, and fruit vegetables and corn (cereals) had a high risk of antimony pollution. Therefore, it is urgent to take soil antimony pollution control measures in the mining area. At the same time, in order to realize the safe use of agricultural land in the mining area, the farmland far away from the low antimony content of the soil in the central area of the mine should be selected as the planting area, and the agricultural products with weak antimony absorption capacity should be planted first.

Microbial community structures and their driving factors in a typical gathering area of antimony mining and smelting in South China.

This study investigated soil microbial community in a typical gathering area of antimony mining and smelting in South China. The physical and chemical properties of different soils (mining waste dumps, flotation tailings, and smelting slag) and depths (0-20 cm, 40-60 cm, and 80-100 cm) were compared. The results showed that antimony (Sb) and arsenic (As) were the main pollutants, and their concentrations were 5524.7 mg/kg and 3433.7 mg/kg, respectively. Xanthates were found in the flotation tailings and smelting slag, and the highest concentration was 585.1 mg/kg. The microbial communities were analyzed by high-throughput sequencing, and it was shown that Proteobacteria, Acidobacteria, Chlorobacterium, Bacteroides, and Actinomycetes were the dominant taxa at the phylum level. There were obvious differences in microbial community structure in different sites. The dominant microorganism in the mining site was Chujaibacter. Subgroup_2_unclassified and Gemmatimonadaceae_unclassified were the prevalent microorganisms in the flotation and smelting sites, respectively. As, Sb, and xanthates were the main factors affecting the diversity and composition of bacteria in the flotation tailings and smelting slag areas. Therefore, this study provides experimental guidance and a theoretical basis for soil antimony pollution quality assessment, biological treatment, and environmental remediation.

Transcriptome analysis of an arsenite-/antimonite-oxidizer, Bosea sp. AS-1 reveals the importance of the type 4 secretion system in antimony resistance

Bosea sp. AS-1 is an arsenite [As(III)] and antimonite [Sb(III)] oxidizer previously isolated by our group from the Xikuangshan Antimony (Sb) Mine area. Our previous study showed that Bosea sp. AS-1 had a preference for oxidizing As(III) or Sb(III) with different carbon sources, which suggested that different metabolic mechanisms may be utilized by the bacteria to survive in As(III)- or Sb(III)-contaminated environments. Here, we conducted whole-genome and transcriptome sequencing to reveal the molecular mechanisms utilized by Bosea sp. AS-1 to resist As(III) or Sb(III). We discovered that AS-1 acquired various As- and Sb-resistant genes in its genome and might resist As(III) or Sb(III) through the regulation of multiple pathways, such as As and Sb metabolism, the bacterial secretion system, oxidative phosphorylation, the TCA cycle and bacterial flagellar motility. Interestingly, we discovered that genes of the type IV secretion system (T4SS) were activated in response to Sb(III), and inhibiting T4SS activity in AS-1 dramatically reduced its oxidation efficiency and tolerance to Sb(III). To our knowledge, this is the first study showing the activation of T4SS genes by Sb and a direct involvement of T4SS in bacterial Sb resistance. Our findings establish the T4SS as an important Sb resistance factor in bacteria and may help us understand the spread of Sb resistance genes in the environment.

Trivalent antimony removal using carbonaceous nanomaterial loaded with zero-valent bimetal (iron/copper) and their effect on seed growth

As rapid industrial and social growth, antimony mines are the overexploited, leading to the accumulation of trivalent antimony in the aquatic environment near smelters, which harm human health. To eradicate trivalent antimony from water, an innovative nanomaterial in the form of sludge biochar loaded with zero-valent bimetal was synthesized using a liquid-phase reduction method. The adsorption performance of the nanomaterial for trivalent antimony was investigated based on a series of adsorption experiments using sludge biochar, nano zero-valent iron biochar, and nano zero-valent bimetal biochar. The results showed that the optimal adsorption performance of the three nanomaterials for trivalent antimony, considering the economic practicability, was highlighted at solution pH of 3 and 0.05 g of nanomaterial. Additionally, the maximum adsorption capacity of sludge biochar, nano zero-valent iron biochar, and nano zero-valent bimetal biochar is 3.89 mg g−1 at 35 °C, 32.01 mg g−1 at 25 °C, 50.96 mg g−1 at 25 °C, respectively. The adsorption process of sludge biochar is endothermic, resulting in an increase in the adsorption capacity with increasing temperature, whereas the exothermic reaction contributes to decrease in the adsorption capacity at increasing temperature for the other two carbon nanomaterials. The inhibitory effect of coexisting ions was in the order: Al3+ > NH4+ > Na+ > K+; CO32− > CH3COO− > H2PO4− > S2−. Additionally, nanomaterials promoted seed germination and growth. Investigation of the adsorption mechanism using X-ray photoelectron spectroscopy showed that trivalent antimony was oxidised to pentavalent antimony, and Fe(III) was reduced to Fe(II). The formed primary battery formed by copper ions and iron acclerated electron transfer and improved the adsorption rate. This implied that trivalent antimony could be removed through the synergistic action of the adsorption behaviour and redox reaction. Therefore, the biochar loaded with the zero-valent bimetal serves as a pathway for eradicating trivalent antimony.

Collection Tubes Can Cause False Elevations in Occupational and Clinical Evaluation of Antimony Exposure.

Occupational exposure to antimony has become rare in the past decades due to antimony mine closures and technological improvement in antimony processing plants in the USA. Although antimony's ubiquitous presence in plasticwares does not pose known health risk, it can present as a potential contaminant to antimony analysis for occupational exposure assessment. To understand the level of antimony contamination from plastic collection devices, we evaluated two different whole-blood plastic collection tubes that are routinely used for trace and toxic element assessment: royal blue BD Vacutainer® EDTA tube and Greiner VACUETTE® trace elements sodium heparin tube. We analyzed how different fill volumes may impact the concentrations of antimony detected. Although both collection tubes can introduce antimony contaminations to nitric acid and neutral buffer rinse, the Greiner heparin tube introduces a significantly lower amount of antimony to freshly collected whole-blood samples compared to the BD EDTA tube. When patients' samples are collected with BD EDTA tubes, they would exhibit elevated antimony concentrations that can be interpreted as potential antimony exposure. We conclude that the royal blue BD EDTA plastic tube is not suitable to evaluate blood antimony levels, and laboratories need to validate their own alternative sources when the glass tubes are not available.

Mineral Paragenesis, formation stages and trace elements in sulfides of the Olympiada gold deposit (Yenisei Ridge, Russia)

The mineral sequence and LA-ICP-MS study of the trace-elements distribution in chalcogenides (arsenopyrite, pyrite, pyrrhotite, sphalerite, chalcopyrite, ullmannite, tetrahedrite, berthierite, stibnite, gudmundite, jamesonite) of the Olympiada gold ore deposit (Yenisei Ridge, Russia) are presented. The deposit was formed in three stages, separated by tectonic breaks. Early (I) corresponds to the paragenesis of acicular arsenopyrite + pyrite + pyrrhotite. At the stage of base-metal sulfides (II), the deposition of the bulk of chalcopyrite, sphalerite and galena occurred. Mineral associations of these stages determined the gold-arsenic (Au-As) type of ores. The stage of late sulfides (III) is characterized by the paragenesis of antimony minerals (stibnite + berthierite + gudmundite) and corresponds to the gold-antimony (Au-Sb) ore type. Commercial concentrations of gold were formed at the early sulfides stage in the lattice bonded and nanosize mode in acicular arsenopyrite (12.5–1,512 ppm). The progress of the ore deposition process with the formation of late polymetallic and stibnite-berthierite mineralization led to recrystallization of early sulfides (prismatic arsenopyrite Au ∼ 36.4 ppm → dipyramidal arsenopyrite Au ∼ 0.5 ppm), remobilization and re-deposition of gold in a native form. Pyrite of the deposit does not contain significant amounts of gold (∼0.4 ppm). Silver is absent in early sulfides, but is concentrated in tetrahedrite (348.0–3,811 ppm), jamesonite (0.1–7.7 ppm), berthierite (0.1–2.3 ppm) and stibnite (0.2–2.0 ppm) of the later stage (III). Early sulfides (stage I) are characterized by the As-Au-W-Se-Te geochemical association; polymetallic sulfides (stage II) — by the Cu-Zn-Pb-Cd-In association; and late sulfides (stage III) — by the Sb-Co-Ni-Te-Bi-Pb-Hg-Ag association.