Distribution Of Antimony Research Articles

Uniform Sb doping of ZnO films with controllable morphology and enhanced optical property

In order to provide an effective and reliable approach to solving the difficulties in p-type modification of ZnO nanomaterials, in this work, we successfully synthesized ZnO films with uniform antimony distribution through low temperature aqueous growth method. The growth quality and dopant distribution of Sb-doped ZnO (SZO) films were evaluated by high-resolution micro-structural characterizations, and the growth mechanism for SZO films with various doping concentrations was discussed and revealed. Uniform and dispersive Sb distribution within SZO films contributed to the light transmittance of SZO films. The blue-shifted UV emission accompanied with weak visible light emission of SZO films were observed in room-temperature photoluminescent (PL) spectra, the rare yellow-red light emission and XPS results confirmed the existence of SbZn-related complex defects. This type of SZO films is competitive and promising for serving as the highly photo-conductive and photo-sensitive ZnO-based nanomaterials. And SZO films could be served as the basis for realizing the purpose of p-type modification with high efficiency and excellent stability.

A study of Physicochemical Parameters, Heavy Metals and Algae in the Euphrates River, Iraq

For many individuals, heavy metal persistence and toxicity are severe problems. Most of these heavy metals collect in wastewater from effluents discharged by various industries. The efficient re-use of these particles as catalysts is another new development in research that complements the success of hazardous metal particle removal. Five locations along the Euphrates River in western Iraq’s Anbar Governorate were the subject of the research (Husaibah Al-Sharqiah, Al-Karābilah, Barwana, Al-Garma, Al-Forat sub district) and for four seasons (Summer, Autumn, Winter, and Spring) from November 2021 to November 2022 in order to examine how the physical and chemical characteristics of the water in the Euphrates River vary over space and time in these areas. Based on these locations of garbage, contaminants, and heavy metal components that may flow into the river without environmental management, sampling locations on the Euphrates River were chosen. In order to better understand the distribution of heavy metals (HMs: Arsenic (As), Antimony (Sb), Selenium (Se), Molybdenum (Mo), Cyanide (CN-), and Chromium (Cr) in river sediments, five locations in western Iraq were chosen for the research. The PH, electrical conductivity (EC), algaes, and sediments (Nitrate (NO3), sulfate (SO4), and HMs content) were all measured in the river’s edge water. A qualitative research was also carried out at various times of year and locations. 104 different kinds of algae were found, and some of them dominated all the research locations. In each station near the beginning of the estuary, the quantitative research revealed a rise in the number of algae species indicative of pollution, confirming that these sites are impacted by the pollutants from untreated sewage discharged into the Euphrates River in those locations. The average concentrations of HMs and compounds in the sediments were as follows: SO4> NO3>Mo>Cn>Cr>Sb>Se>As. According to the investigation, the HMs polluted cities in the following ways: Sediment concentrations are greater in Husaibah Al-Sharqiah, Al-Karbilah, Barwana, Al-Garma, and Al-Forat subdistrict cities.

Geochemical and Microbiological Composition of Soils and Tailings Surrounding the Komsomolsk Tailings, Kemerovo Region, Russia

Microorganisms have the potential to address environmental pollution, but the interaction mechanism between microorganisms and mine tailings is not well understood. This work was aimed at determining the bacterial isolates in soils and mine tailings and evaluating the distribution of metals, antimony (Sb), and arsenic (As) in the soils around the Komsomolsk tailings. Areas with high concentrations of As, Sb, cadmium (Cd), and lead (Pb) were found. Assessment based on the value of the contamination factor (CF) indicated large-scale As, Sb, Pb, Cd, iron (Fe), bismuth (Bi), and beryllium (Be) pollution, especially in soils sampled from the northeast direction of the mine tailings. Soils had a higher number of CFUs per g of dry weight than did the tailings, ranging from 84 × 106 to 3.1 × 109 and from 20 × 106 to 1.7 × 109, respectively. Arsenic exhibited a positive statistical correlation with the number of CFUs of Agrococcus and Staphylococcus. In addition, a positive correlation was found between the concentration of Co and the number of CFUs of Moraxella and Microbacterium. The Sb exhibited a positive correlation with Streptomyces. These results can be used to develop methods for waste reclamation, including the use of isolated bacterial strains for arsenic removal by precipitation.

Evaluation of Pollution Level, Spatial Distribution, and Ecological Effects of Antimony in Soils of Mining Areas: A Review.

The first global-scale assessment of Sb contamination in soil that was related to mining/smelting activities was conducted based on 91 articles that were published between 1989 and 2021. The geographical variation, the pollution level, the speciation, the influencing factors, and the environmental effects of Sb that were associated with mining/smelting-affected soils were analyzed. The high Sb values mainly occurred in developed (Poland, Italy, Spain, Portugal, New Zealand, Australia) and developing (China, Algeria, Slovakia) countries. Sb concentrations of polluted soil from mining areas that were reported in most countries significantly exceeded the maximum permissible limit that is recommended by WHO, except in Turkey and Macedonia. The soil Sb concentrations decreased in the order of Oceania (29,151 mg/kg) > North Africa (13,022 mg/kg) > Asia (1527 mg/kg) > Europe (858 mg/kg) > South America (37.4 mg/kg). The existing extraction methods for Sb speciation have been classified according to the extractant, however, further research is needed in the standardization of these extraction methods. Modern analytical and characterization technologies, e.g., X-ray absorption spectroscopy, are effective at characterizing chemical speciation. Conditional inference tree (CIT) analysis has shown that the clay content was the major factor that influenced the soil Sb concentration. Non-carcinogenic risks to the public from soil Sb pollution were within the acceptable levels in most regions. An Sb smelter site at the Endeavour Inlet in New Zealand, an abandoned open-pit Sb mine in Djebel Hamimat, Algeria, an old Sb-mining area in Tuscany, Italy, and Hillgrove mine in Australia were selected as the priority control areas. Cynodon dactylon, Boehmeria, Pteris vittata, and Amaranthus paniculatus were found to be potential Sb accumulators. All of the values of bioaccumulation factors for the crops were less than one. However, ingestion of Sb through crop consumption posed potential non-carcinogenic health risks, which should not be neglected. The soil variables (pH, Eh, total sulfur, carbon nitrogen ratio, total organic carbon, and sulfate), the total Sb and the bioavailable Sb, and heavy metal(loid)s (As, Pb, and Fe) were the major parameters affecting the microbial community compositions.

Occurrence, distribution, and migration of antimony in the Zijiang River around a superlarge antimony deposit zone

Under the environmental changes associated with mine tributaries entering mainstream rivers, differences in the distributions and migration behaviors of metal(loid)s can be found, but the behavior of antimony (Sb) is still poorly understood in this regard. We analyzed the occurrence, distribution, migration, and influencing factors of the Sb concentration in the water body of the Zijiang River (ZR) around a superlarge Sb deposit zone. The total Sb concentrations were 1.45–15.66 μg/L, 3.16–133.63 mg/kg, and 0.83–41.82 μg/L in the ZR surface waters, sediments, and pore waters, respectively; Sb(V) was the predominant form of Sb found in the surface waters. Mining and smelting were the main sources of Sb in the ZR. Spatially, the Sb concentration showed a decreasing trend from the tributaries to the ZR mainstream. In the ZR, the surface-water Sb concentration showed an increasing trend from the upstream to the downstream, while in the sediments and pore waters, the midstream Sb concentrations were higher than the upstream and downstream concentrations; this finding was related to the sediment retention and accumulation behaviors of reservoirs and dams resulting in the secondary release of Sb in sediments. Sb tended to be bound to the solid phase, dominated by amorphous iron (Fe)/aluminum (Al) oxides and calcium in sediments. This study highlights that, based on current Sb migration patterns, the accumulation of sediments carried by tributaries near Sb mines in the midstream ZR and the Sb pollution caused by sediment release will be long-term, and the related environmental consequences need to be further predicted.

Source, Distribution and Potential Risk of Antimony in Water and Sediments of Danjiangkou Reservoir: Impact from Dam.

Danjiangkou Reservoir is the water source of the mid-route of the South-to-North Water Transfer Project. The source, distribution and potential risk of antimony in its water and sediments are rarely reported. In this study, symmetrical investigation results demonstrated that the concentration of antimony in the Han sub-reservoir and water in front of the dam fluctuated at about 0.9 mg L−1, while it was relatively higher and increased with the distance from the dam in Dan sub-reservoir water, with an annual average of 0.93~3.15 mg L−1. In recent years, the concentration of antimony in the Danjiangkou Reservoir showed a downward trend, and the difference between the Han and Dan sub-reservoirs decreased significantly. The antimony in the sediments in the reservoir was primarily derived from the inflowing rivers, and it was higher in the Dan sub-reservoir than in the Han sub-reservoir. The concentration of antimony in the water in the reservoir was considerably higher than the background value in the watersheds, indicating that there is an external input with decreasing input intensity. The content of antimony in the sediments in the reservoir and its inflow rivers was substantially higher than the background value of watersheds, indicating that there is a certain degree of enrichment. In addition, the antimony mining industry in the water source area poses a risk to the water safety of the reservoir. Antimony is not a conventional pollutant. Consequently, the collection of antimony monitoring results is a challenging task. Additionally, this study fills the gap in regional antimony research. Furthermore, the ecological risk assessment of antimony in China is still in its infancy. Unquestionably, the study of the temporal and spatial distribution of antimony concentration will be beneficial for the protection of water sources in relevant regions.

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.

Effects of Antimony on Rice Growth and Its Existing Forms in Rice Under Arbuscular Mycorrhizal Fungi Environment.

Arbuscular mycorrhizal fungi (AMF) can form symbiotic relationships with most terrestrial plants and regulate the uptake and distribution of antimony (Sb) in rice. The effect of AMF on the uptake and transport of Sb in rice was observed using pot experiments in the greenhouse. The results showed that AMF inoculation increased the contact area between roots and metals by forming mycelium, and changed the pH and Eh of the root soil, leading to more Sb entering various parts of the rice, especially at an Sb concentration of 1,200 mg/kg. The increase in metal toxicity further led to a decrease in the rice chlorophyll content, which directly resulted in a 22.7% decrease in aboveground biomass, 21.7% in underground biomass, and 11.3% in grain biomass. In addition, the antioxidant enzyme results showed that inoculation of AMF decreased 22.3% in superoxide dismutase, 9.9% in catalase, and 20.7% in peroxidase compared to the non-inoculation groups, further verifying the negative synergistic effect of AMF inoculation on the uptake of Sb in rice. The present study demonstrated the effect of AMF on the uptake and transport of Sb in the soil–rice system, facilitating future research on the related mechanism in the soil–rice system under Sb stress.

Spatial distribution, geochemical behaviors and risk assessment of antimony in rivers around the antimony mine of Xikuangshan, Hunan Province, China.

Pollutants derived from antimony (Sb) mining can easily cause pollution of surrounding water bodies. However, qualitative source analysis of river pollution is mostly conducted, and quantitative source analysis is still lacking. A total of 21 water samples were collected to analyze the pollution status of the heavy metal element Sb, explore the Xikuangshan (XKS) area river heavy metals pollution mechanism, undertake quantitative analysis of the sources of pollution, and carry out irrigation water suitability assessment and potential ecological risk assessment. The results showed that, compared with the mining non-affected area, the maximum excess multiple of Sb in surface water and rivers in Hunan XKS area is 411.31. When the river fluid flows through the mining-affected area, the heavy metal element Sb content increases rapidly, and then decreases due to dilution process. Positive matrix factorization (PMF) source analysis showed that the main source of Sb pollution in the rivers is the impact of mining and smelting (83.60%), followed by the role of waste rock leaching (16.40%). After irrigation, 27.78% of the river water had strong ecological risks, and 16.67% had extremely strong ecological risks. This achievement provides a theoretical basis and technical guarantee for protecting and using the local water body of the mining area.

Disorder-Induced Degradation of Vertical Carrier Transport in Strain-Balanced Antimony-Based Superlattices

We investigate carrier transport in gallium-free strained-balanced $\mathrm{In}\mathrm{As}/{\mathrm{In}}_{x}{\mathrm{As}}_{1\ensuremath{-}x}\mathrm{Sb}$ type-II superlattices in the presence of positional and compositional disorder. We use a rigorous nonequilibrium Green's function model based on fully nonlocal scattering self-energies computed in the self-consistent Born approximation and a multiband description of the electronic structure. Layer-thickness fluctuations, nonuniform antimony composition, and segregation throughout the superlattice stack lead to as-grown disordered structures that are quite different from the abrupt interface ideal superlattices. We find that regardless of its nature and cause, disorder significantly affects vertical-carrier-transport properties, by impeding the coherent propagation of carriers in the minibands. In particular, the minority-carrier hole mobility is fundamentally limited by the nonideal properties of the superlattice, namely the layer-thickness fluctuation and the nonuniform antimony distribution. Furthermore, upon reducing the temperature, holes become fully localized and transport occurs by hopping, which explains published measured detector data that demonstrates the quantum efficiency, exhibiting a very strong temperature dependence that degrades as the temperature is reduced. As a result, photodetectors that employ holes as minority carriers will be limited in performance, especially for long-wavelength infrared applications at low temperature. However, we find that minority-carrier electron mobility is largely unaffected by disorder, indicating the $p$-type absorbing layer as the preferred option.

Antimony distribution and mobility in different types of waste derived from the exploitation of stibnite ore deposits

Wastes derived from the exploitation of stibnite ore deposits were studied to determine their mineralogical, chemical, and environmental characteristics and establish the Sb distribution and the current and long-term risks of Sb mobilization. Representative samples of mine waste rocks, mine tailings, and smelting waste were studied by X-ray powder diffraction, polarized light microscopy, electron microprobe analysis, and digestion, leaching, and extraction procedures. The main Sb-bearing minerals and phases identified in the smelting waste were natrojarosite, iron (oxyhydr)oxides, mixtures of iron and antimony (oxyhydr)oxides, and tripuhyite; those in the mine tailings and mine waste rocks were iron (oxyhydr)oxides and/or mixtures of iron and antimony (oxyhydr)oxides. Iron (oxyhydr)oxides and natrojarosite had high Sb contents, with maximum values of 16.51 and 9.63 wt% Sb2O5, respectively. All three types of waste were characterized as toxic; the mine waste rocks and mine tailings would require pretreatment to decrease their leachable Sb content before they would be acceptable at hazardous waste landfills. Relatively little of the Sb was in desorbable forms, which accounted for <0.01 and <0.8% of the total Sb content in the smelting waste and mine waste rocks/mine tailings, respectively. Under reducing conditions, further Sb mobilization from mine waste rocks and mine tailings could occur (up to 4.6 and 3.3% of the total content, respectively), considerably increasing the risk that Sb will be introduced into the surroundings. Although the smelting waste had the highest total Sb content, it showed the lowest risk of Sb release under different environmental conditions. The significant Fe levels in the smelting waste facilitated the formation of various Fe compounds that greatly decreased the Sb mobilization from these wastes.

Response of antimony distribution in street dust to urban road traffic conditions

Little is known about the relationship between traffic congestion and antimony (Sb) distribution in street dust, which is essential for Sb control and emission reduction in urban areas. Sb concentrations and mass load of the street dust collected in 19 cities of China were determined before investigating the mechanism of traffic influence on Sb distribution through diverse statistical means. The results showed that the Sb concentrations in each city were 1.10–4.76 times higher than the local background values. Sb concentrations in transportation areas were significantly higher than those in residential and industrial areas, and were significantly affected by road network density. The effect of congestion on Sb load of street dust was influenced by vehicle flowrate. Only when the vehicle flowrate was high, the traffic congestion would promote the increase of Sb load obviously. The improved accounting method showed that the Sb dissipation from brake wear in major Chinese cities were higher than that in Stockholm, Sweden, in 2005. The latent path analysis illustrated that a 1% increase in congestion index was correlated with a 0.886% increase in the Sb load. Compared with Switzerland, which has a typical industrialized Sb consumption pattern, China needs to recycle brake pads in addition to taking various measures to alleviate traffic congestion and reduce brake pad wear, despite the fact that the maximum health risk of Sb was far below the safety threshold. This study will provide valuable insights for urban traffic management and brake pad recycling.

Effects of four woody plant species revegetation on habitat improvement and the spatial distribution of arsenic and antimony in zinc smelting slag

Broussonetia papyrifera, Cryptomeria fortunei, Arundo donax, and Robinia pseudoacacia were planted on a zinc smelting slag site. The habitat conditions and spatial distribution of arsenic (As) and antimony (Sb) in slag were analyzed after seven years of restoration. The results showed that the pH, conductivity (EC), and moisture content of phytoremediated slag were lower than those of the control slag. The redox potential (Eh) and EC decreased with increasing slag depth. Phytostabilization significantly increased the contents of total nitrogen (TN), total phosphorus (TP), available nitrogen (AN), available phosphorus (AP), and dissolved organic carbon (DOC) in slag. TN, AN, AP, and DOC in slag showed obvious surface polymerization. Phytostabilization increased the content of calcite and gypsum in the slag. As and Sb concentrations were significantly lower than control slag, with an average decrease of 651–844 and 422–693 mg·kg −1, respectively. Residual As and Sb in phytoremediated slag was the most present form, the proportion of which was higher than that in the control slag. The proportions of calcium-bound and aluminum-bound As and Sb were lower. The contents of arsenic and antimony in plants had lower levels and followed the order of roots > leaves > stems. As and Sb showed a strong positive correlation with pH, EC, moisture content, and a negative correlation with TN, TP, AN, AP, and DOC. In summary, phytostabilization significantly improved slag site conditions and reduce As and Sb available concentrations. Novelty statement Co-contamination of As and Sb is common in mining areas because of similar chemical properties. There are only few reports on the effects of matrix modification and phytoremediation (without additional soil cover) on the soil physicochemical properties, the spatial distribution, and the bioavailability of As and Sb in zinc slag with an alkaline pH. The research determined that phytostabilization significantly improved slag site conditions and reduce As and Sb available concentrations. The results obtained can be used as necessary information for the large-scale ecological restoration or vegetation reconstruction of zinc smelting slag yards.

Distribution of Antimony and Gold in Old Tailings and Heaps at the Milešov Locality (Příbram District)

Antimony ores were extracted and processed near the village of Milešov (Příbram district) for about twenty years in the second halfof the 19th century. Large heaps and a small sludge pond were left behind after this period. In 1988, this locality was inspected andsampled in order to gather information about residual resources of gold and antimony. The original archive data from this surveywere now studied again and interpreted using modern statistical and geostatistical methods. The interpolations methods chosenfor this purpose were inverse distance weighting (IDW), simple kriging and geostatistical sequential Gaussian simulation (SGS).These procedures allowed for a much more accurate determination of the spatial distribution of the elements or substances studied.The results showed significantly higher volumes and a more accurate localization of the studied elements in both bodies (heap andtailings). This procedure can be considered as the basis of a new methodology for the assessment of similar objects.

Spatial Distribution and Environmental Risk of Arsenic and Antimony in Soil Around an Antimony Smelter of Qinglong County.

The purpose of this study was to investigate the distribution of arsenic (As) and antimony (Sb) in soils around an antimony smelter at Qinglong together with the soil pollution levels and potential ecological risk. The results show that (1) total concentrations of As (23 ~ 539mg/kg) and Sb (19.7 ~ 5681mgkg-1) were higher than the Guizhou province-level background values (As, 20; Sb, 2.24), especially Sb. Their dominant geochemical speciation was the residual fraction which accounted for > 90% of the total concentrations. (2) The distribution of As and Sb in soils influenced mainly by land-use type, altitude, predominant wind direction, and distance from the pollution source. (3) The geo-accumulation index shows that the soil was highly contaminated with Sb and moderately with As. The potential ecological risk index shows that As posed a moderate risk and Sb a high risk. The general ecological risk was classified as high risk. However, the risk index coding method shows low environmental risk from As and Sb.

Indium and Antimony Distribution in a Sphalerite from the “Burgstaetter Gangzug” of the Upper Harz Mountains Pb-Zn Mineralization

The sphalerite from the Burgstaetter Gangzug, a vein system of the Upper Harz Mountain nearby the town of Clausthal-Zellerfeld, exhibits a very interesting and partly complementary incorporation pattern of Cu, In and Sb, which has not yet been reported for natural sphalerite. A sphalerite specimen was characterized with electron probe micro-analysis (EPMA) and atom probe tomography (APT). Based on the EPMA results and a multilinear regression, a relation expressed as Cu = 0.98In + 1.81Sb + 0.03 can be calculated to describe the correlation between the elements. This indicates, that the incorporation mechanisms of In and Sb in the structure differ substantially. Indium is incorporated with the ratio Cu:In = 1:1 like in roquesite (CuInS2), supporting the coupled substitution mechanism 2Zn2+ → Cu+ + In3+. In contrast, Sb is incorporated with a ratio of Cu:Sb = 1.81:1. APT, which has a much higher spatial resolution indicates a ratio of Cu: Sb = 2.28: 1 in the entire captured volume, which is similar to the ratio calculated by EPMA, yet with inhomogeneities at the nanometer-scale. Analysis of the solute distribution shows two distinct sizes of clusters that are rich in Cu, Sb and Ag.

Geogenic and anthropogenic interactions at a former Sb mine: environmental impacts of As and Sb

Mining activities are acknowledged to introduce contaminants into localised environments and cause wider spread diffuse pollution. The concentration, distribution and fate of arsenic (As) and antimony (Sb) were studied at the former metalliferous Louisa Mine at Glendinning, Scotland. Soils and surface water were sampled and subsequently analysed to map the distribution of contamination and identify pollution sources. The maximum concentrations of As and Sb of 15,490 and 1504.2 mg kg−1, respectively, were determined in soils associated with the ore processing area and spoil heaps. The fractions of dissolved As and Sb in soils were < 1 and < 5% of total soil content, respectively, confirming findings of previous studies that As and Sb are relatively immobile. Yet, the concentrations of As and Sb released by soils exceeded regulatory limits. Concentrations of As and Sb in surface water in the immediate vicinity of the mine were impacted by a gully discharge, but rapidly diluted. While the concentrations affected by the run-off waters did not exceed EU environmental standards for freshwater, the concentrations of both, As and Sb, sharply increased above the said environmental standards approximately 100 m downstream of the mine site. The unaltered As-to-Sb ratio in water samples suggests a geogenic source. While there is a justifiable concern about the soil pollution caused by the historic mining in the area, the Glenshanna Burn is affected more by indigenous geochemical processes than the derelict mine.

Distribution, accumulation, and potential risks of heavy metals in soil and tea leaves from geologically different plantations.

Risk assessment regarding heavy metals in tea is crucial to ensure the health of tea customers. However, the effects of geological difference on distribution of heavy metals in soils and their accumulation in tea leaves remain unclear. This study aimed to estimate the impacts of geological difference on distribution of cadmium (Cd), lead (Pb), thallium (Tl), mercury (Hg), arsenic (As), antimony (Sb), chromium (Cr), nickel (Ni), and manganese (Mn) in soils and their accumulation in tea leaves, and further evaluate their health risks. 22 soils and corresponding young tea leaves (YTL) and old tea leaves (OTL), from geologically different plantations, were sampled and analyzed. Results showed that heavy metals concentrations in soils, derived from Permian limestone and Cambrian weakly mineralized dolomite, were obviously greater than those from Silurian clastic rock. The geological difference controlled the distribution of soil heavy metals to a large extent. Contents of Cd, Tl, and Mn in tea leaves mainly depended on their contents in soils. Soil Hg, Pb, As, and Sb contents may not be the only influencing factors for their respective accumulation in tea leaves. More attentions should be paid to soil acidification of tea plantations to ensure the tea quality security. Target hazard quotients (THQ) of Cd, Pb, Tl, Hg, As, Sb, Cr, and Ni and hazard index (HI) via tea intake were below one, indicating no human health risk. The non-mineralized Silurian area was less at risk of heavy metals accumulation in tea leaves than the Cambrian metallogenic belt and the Permian Cd-enriched zone. This study could provide an important basis to understand and mitigate the potential risks of heavy metals in tea.

Determining the effects of past gold mining using a sediment palaeotoxicity model

Ore processing techniques used in Yellowknife's largest mining operation, Giant Mine, is responsible for the atmospheric release of approximately 20,000 t of particulate arsenic trioxide and other heavy metal(loids). This rapid deposition of heavy metal(loids) may have caused ecological disturbances to aquatic food webs. Here we use 210Pb and 137Cs dated lake sediment cores from 20 lakes within a 40 km radius of Yellowknife to examine the spatial-temporal distribution of arsenic, antimony and lead. Further, we model the toxicity of the sediment to aquatic biota pre-, during, and post-mining using palaeotoxicity modelling, enrichment factor assessment, and comparisons to national sediment quality guidelines. We found that metal(loid) profiles in sediment peaked during the height of mining operations. These peak metal(loid) concentrations were highest in lakes near the mine's roaster stack, and decreased with distance from the historic mine. Palaeotoxicity modelling of lake sediment archives indicate that there is no significant difference in the mean predicted toxicity of pre- and post-mining samples (p = 0.14), however mining activities in the region significantly increased the predicted toxicity of sediments to aquatic organisms during mining operations (p < 0.001). In the years since roasting processes ceased, the mean palaeotoxicity of all lakes has decreased significantly (p < 0.05), indicating a projected pattern of biological recovery. Importantly, some lakes remain at an elevated risk, indicating that aquatic ecosystems in Yellowknife may continue to have lingering effects on aquatic biota despite the closure of the mine two decades ago.

Distribution of Antimony in Copper-Zinc Concentrate Metallurgical Processing Products

The distribution of antimony in sulfide copper-zinc concentrates processing products manufactured according to a production scheme including autogenous smelting, matte conversion to blister copper, and flotation extraction of metals from slags, is evaluated. The main products concentrating antimony concern autogenous smelting and conversion dust. The proportion of antimony transferred into these products does not exceed 40%, and the rest is removed with slag flotation treatment tailings. With a relatively low antimony content in blister copper its electrolysis sludge contains up to 15% Sb. Dust and anode sludge are considered as a source of antimony production.