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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]

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]

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]

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]

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]

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]

• Sb concentrations varied with aquifers, whereas As differed seasonally. • Sb and As co-pollution types were identified by cluster analysis. • Mine activities have significant impacts on karst groundwater geochemistry. • Elevated SO 4 2− was related to Sb pollution indicated by tracing sulfate sources. The elevated levels of antimony (Sb) and arsenic (As) in groundwater caused by mine activities is of particular global concern. Understanding pollution mechanism of Sb and As related to mine activities and their influence on karst groundwater geochemistry is of great significance. However, it is still unclear. To address such questions, Sb and As and major ions, δ34S and δ18O of dissolved sulfate as well as δD and δ18O of water were analyzed for groundwater sampled from three main karst aquifers at the Xikuangshan (XKS) antimony mine from 2013 to 2017. Spatial and temporal variations of Sb and As of the three main karst aquifers were characterized as that, (1) Sb concentrations, rather than As, varied with aquifers, with high Sb (1–50 mg/L) of the D 3 s2 and C 1 y3 aquifers and low Sb (0.01–1.0 mg/L) of the D 3 x4 aquifer; (2) As concentrations had significant seasonal effect that was higher in winter and lower in summer, whereas Sb concentrations did not differ seasonally. Here we applied a recently developed cluster analysis method as well as geochemical indicators to identify pollution types of Sb and As in groundwater related to complex mine activities, and further to reveal main effects on karst groundwater geochemistry. The cluster analysis yielded a classification of four clusters, which was confirmed by principal component analysis. The groundwater of cluster 3 is of weakly alkaline HCO 3 -Ca type with low Sb (<0.015 mg/L) and low As (<0.005 mg/L), which is typical karst groundwater controlled by limestone dissolution. Whereas the other three clusters with high concentrations of Sb and As were identified to represent three pollution patterns dominated by oxidative dissolution of stibnite, leaching of mine wastes, and mixed pollution, respectively. Moreover, the effects of long-term mine activities on karst groundwater geochemistry are revealed, including: (1) Hydrogeochemical compositions of groundwater changed from HCO 3 -Ca type to SO 4 -Ca type. (2) Sulfuric acid significantly participated in carbonate weathering. (3) Weathering of silicate (main as silicified limestone) by H 2 CO 3 and H 2 SO 4 was accelerated. (4) Cation-exchange was enhanced to dominate groundwater geochemistry. Another striking finding is that sulfur and oxygen isotopes of sulfate can effectively distinguish sulfate sources related to mine activities and to trace Sb sources in karst groundwater. [ABSTRACT FROM AUTHOR]

Abstract: A sediment core in Lake Qinghai in northwest China was collected in 2006. 137Cs and 210Pb activities were analyzed to investigate the chronology of the sediment core. Sb and Pb concentrations, and Pb stable isotopic ratios were analyzed to study the historical atmospheric deposition records and sources of Sb over the past 15 centuries. The Sb concentration was 4.21±1.52μg/g in the sediments, its vertical distribution of Sb shows three large peaks in the recent two centuries, 1799, 1896 and 1944, coincided with Sb contamination from large wars, respectively. The peak in 1920 responded the large earthquake that happened in northern China, which was not far away from Lake Qinghai. The Sb/Pb ratio, 206Pb/207Pb and 208Pb/206Pb results suggest that Sb and Pb were probably from the ores in South China and coals in North China before 1965, but obviously from uses of leaded gasoline after 1965. [ABSTRACT FROM AUTHOR]

Abstract: To study the characteristics of antimony (Sb) bioaccumulation under high Sb background values, aquatic, amphibious and terrestrial biological samples were collected in the vicinity of the Xikuangshan (XKS) Sb mine area in China. Hydride generation-atomic fluorescence (HG-AFS) analysis showed that Sb concentrations in terrestrial invertebrates (average 30,400μgkg−1 dry wt.) were higher than those in aquatic (average 5200μgkg−1 dry wt.) and amphibian (average 2300μgkg−1 dry wt.) biological samples. Within 1km distance of the XKS Sb mine area, grasshoppers (Acrida chinensis) and earthworms (Pheretima aspergillum) had the highest Sb amounts of 17,300±3200 and 43,600±47,700μgkg−1 dry wt., respectively. No Sb biomagnifications were observed. The bioavailability of Sb was found to be lower than those of As and Hg. A preliminary conclusion is that antagonistic effects exist between Sb and Hg accumulation in biological samples from aquatic environments. Our study is the first to report such antagonistic effects between Sb and Hg. If this deduction proves to be correct, it should be taken into consideration in assessing human health risks, especially when Sb and Hg concentrations in the aquatic environments are high. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we determined the concentrations of antimony species (antimonite (Sb(III)), antimonate (Sb(V)) and dissolved inorganic antimony (DISb)) and arsenic, in Bohai Bay seawaters, as well as the relationships of the analytes with environmental factors such as seawater characteristics (e.g., suspended particulate material (SPM), salinity and total organic carbon (TOC)), heavy metals, nutrients and phytoplankton species, and evaluated the sources of arsenic and antimony. Dissolved arsenic and antimony concentrations in the surface waters were ranging spatially from 1.03 to 1.26ng/ml and 0.386 to 1.075ng/ml, with mean values of 1.18 and 0.562ng/ml, respectively. Sb(V) as the prominent chemical species constituted about 89%. Regarding arsenic concentrations in the surface waters, there was a tendency for a small variation. However, antimony species concentrations were much variable than arsenic. The highest arsenic and antimony concentrations were found near the Haihe Estuary. These distribution patterns were controlled mainly by environmental factors, biological activities and sources. In this region, DISb and Sb(V) negatively correlated with salinity. Besides, arsenic and antimony correlated well with the nutrients, chlorophyll a and phytoplankton, implying that arsenic and antimony had been involved in biological cycling. In addition, according to our estimate, about 333.5×108 mg/year of arsenic and 454.2×108 mg/year of antimony reached Bohai Bay via rivers. [ABSTRACT FROM AUTHOR]

Mining activities can result in serious contamination of soil by heavy metal(loid)s. In this study, the sources and spatial distribution of metal(loid)s, and the risks to public health from these metal(loid)s at an abandoned arsenic mine site were explored. The mean concentrations of arsenic (As), cadmium (Cd), mercury (Hg), manganese (Mn), lead (Pb), antimony (Sb), strontium (Sr), and thallium (Tl) in the soil in the mining area were higher than the mean background values. The main pollutants from the mining activities were As, Hg, and Sb. Five pollutant sources were identified using an approach that combined statistical methods, a positive matrix factorization model, and historical information analysis. As, Hg, Sb, and Tl were associated with the mining resources and related activities (37.29%); Mn (15.57%) and Sr (15.96%) were mainly from crustal origin and pedogenesis, respectively; Pb, Sb, and Tl were mainly from industrial sources (17.57%), and Cd was mainly from the production and application of phosphorous fertilizer (13.60%). Using incremental spatial autocorrelation crystallized that As, Hg, and Sb were mainly contained within 500 m of their source. There were formed existing non-carcinogenic hazards and carcinogenic risks from As, and potential carcinogenic risks from Cd, in the soil for those living locally. [Display omitted] • As, Hg, Sb and Tl pollution deserve special attention in arsenic-containing mine. • Integration of GIS, PCA, ISA, PMF model and field study. • Five anthropogenic sources were identified and quantified by PMF. • The soil metal(loid)s distribution, source and diffusion range were quantified. [ABSTRACT FROM AUTHOR]

Mining activities of antimony (Sb) and arsenic (As) typically result in severe environmental contamination. These contaminants accumulate in rice and thus threaten the health of local residents, who consume Sb- and As-enriched rice grains. Microorganisms play a critical role in the transformation and transportation of Sb and As in paddy soil. Thus, an understanding of the microbiology of contaminated sites would promote the production of safe agricultural products. In this study, six Sb- and As-contaminated rice fields near an active Sb-mining area were investigated. The Sb and As concentrations of all samples were elevated compared to the background level in China. Nitrate, total As, total Sb, and Fe(III) were the major determinants of the microbial community structure. Seven bacterial taxa (i.e. Bradyrhizobium , Bryobacter , Candidatus Solibacter , Geobacter , Gemmatimonas , Halingium , and Sphingomonas) were identified as the core microbiome. These taxa were strongly correlated with the As and Sb contaminant fractions and likely to metabolize As and Sb. Results imply that many soil microbes can survival in the Sb/As contaminated sites. • Rice paddy was collected from various field in Sb contaminated site. • Microbial communities were characterized using amplicon sequencing. • Core microbiome of the paddy was obtained. • Environment-microbe interaction were investigated. [ABSTRACT FROM AUTHOR]

Abstract: Environmental contamination due to uncontrolled e-waste recycling is an emerging global issue. Antimony (Sb) is a toxic element used in semiconductor components and flame retardants for circuit board within electronic equipment. When e-waste is recycled, Sb is released and contaminates the surrounding environment; however, few studies have characterized the extent of this problem. In this study, we investigated Sb and arsenic (As) distributions in indoor dust from 13 e-waste recycling villages in Guiyu, Guangdong Province, southeastern China. Results revealed significantly elevated concentrations of Sb (6.1–232mg/kg) in dust within all villages, which were 3.9–147 times higher than those from the non e-waste sites, indicating e-waste recycling was an important source of Sb pollution. On the contrary, As concentrations (5.4–17.7mg/kg) in e-waste dusts were similar to reference values from the control sites. Therefore, dusts emitted from e-waste recycling may be characterized by high Sb/As ratios, which may help identify the contamination due to the e-waste recycling activities. [Copyright &y& Elsevier]