High Concentrations Of Antimony Research Articles

Antimony mobility in soil near historical waste rock at the world's largest Sb mine, Central China

Soil near waste rock often contains high concentrations of antimony (Sb), but the mechanisms that mobilize Sb in a soil closely impacted by the waste rock piles are not well understood. We investigated these mobility mechanisms in soils near historical waste rock at the world's largest Sb mine. The sequential extraction (BCR) of soil reveal that over 95 % Sb is present in the residual fraction. The leached Sb concentration is related to the surface protonation and deprotonation of soil minerals. SEM-EDS shows Sb in the soil is associated with Fe and Ca. Moreover, X-ray absorption spectroscopy (XAS) results show Sb is predominantly present as Sb(V) and is associated with Fe in the form of tripuhyite (FeSbO4) as well as edge- and corner-sharing complexes on ferrihydrite and goethite. Thus, Fe in soils is important in controlling the mobility of Sb via surface complexation and co-precipitation of Sb by Fe oxides. The initially surface-adsorbed Sb(V) or co-precipitation is likely to undergo a phase transformation as the Fe oxides age. In addition, Sb mobility may be controlled by small amounts of calcium antimonate. These results further the understanding of the effect of secondary minerals in soils on the fate of Sb from waste rock weathering and inform source treatment for Sb-contaminated soils.

Effluents from the copper electrorefining as a secondary source of antimony: Role of mass transfer on the recovery by electrodeposition

The limited availability of antimony has increased the need for exploiting alternative sources to its direct extraction from stibnite deposits. Furthermore, introducing recovery techniques in industries where antimony is released in wastewaters leads to more responsible production routes. In this work, electrodeposition is employed to recover the antimony present in a secondary waste effluent of the copper electrorefining that is highly concentrated in hydrochloric acid. The electrochemical characterization of the system was conducted by voltammetry to identify a range of suitable operating conditions for the potentiostatic and galvanostatic electro-recovery of antimony. In potentiostatic mode, the progress of the secondary electrode reactions of hydrogen and chlorine evolution at potentials more cathodic than −0.38 V vs. Ag/AgCl causes the detachment and redissolution of the deposited antimony. Operating under galvanostatic control, similar effects were observed when the limiting current density is exceeded. Current efficiency and specific energy consumption values above 50 % and below 65 kW·h·kg−1, were achieved below the limiting current density (1.265 mA·cm−2). The operational range where electrodeposition of antimony is accelerated at increasing current densities can be broadened at intensified hydrodynamic conditions and higher concentrations of antimony. The detrimental effect of the hydrogen evolution reaction on the recovery of antimony decreases at high HCl concentrations.

Antimony Immobilization in Primary-Explosives-Contaminated Soils by Fe-Al-Based Amendments.

Soils at primary explosives sites have been contaminated by high concentrations of antimony (Sb) and co-occurring heavy metals (Cu and Zn), and are largely overlooked and neglected. In this study, we investigated Sb concentrations and species and studied the effect of combined Fe- and Fe–Al-based sorbent application on the mobility of Sb and co-occurring metals. The content of Sb in soil samples varied from 26.7 to 4255.0 mg/kg. In batch experiments, FeSO4 showed ideal Sb sorption (up to 97% sorption with 10% FeSO4·7H2O), whereas the sorptions of 10% Fe0 and 10% goethite were 72% and 41%, respectively. However, Fe-based sorbents enhanced the mobility of co-occurring Cu and Zn to varying levels, especially FeSO4·7H2O. Al(OH)3 was required to prevent Cu and Zn mobilization. In this study, 5% FeSO4·7H2O and 4% Al(OH)3 mixed with soil was the optimal combination to solve this problem, with Sb, Zn, and Cu stabilizations of 94.6%, 74.2%, and 82.2%, respectively. Column tests spiked with 5% FeSO4·7H2O, and 4% Al(OH)3 showed significant Sb (85.85%), Zn (83.9%), and Cu (94.8%) retention. The pH-regulated results indicated that acid conditioning improved Sb retention under alkaline conditions. However, no significant difference was found between the acidification sets and those without pH regulation. The experimental results showed that 5% FeSO4·7H2O + 4% Al(OH)3 without pH regulation was effective for the stabilization of Sb and co-occurring metals in primary explosive soils.

A simple graphene modified electrode for the determination of antimony(III) in edible plants and beverage

Antimony(III) is a rare electroactive specie present on Earth, whose concentration is not typically determined. The presence of high concentrations of antimony is responsible for a variety of diseases, which makes it desirable to find convenient and reliable methods for its determination. We have developed a convenient glassy carbon modified electrode with electroreduced graphene oxide GC/rGO for the first time determination of Sb(III) in commercial lettuce, celery, and beverages. The surface of the electrode was characterized by scanning electron microscopy (SEM) and cyclic voltammetry, indicating a heterogeneous and rough surface with a real area of 0.28 cm2, which is ~2.5 times the area of GC. The optimal chemical and electrochemical parameters used were: sodium acetate buffer (pH = 4.3), an accumulation potential of −1.0 V and an accumulation time of 150 s. The analytical validation was developed evaluating the linear range (10–60 µg L−1), limit of detection (2.5 µg L−1), accuracy, repetibility and reproducibility with satisfactory results (relative standard deviation (RSD) values lower than 10%). All the analyzes performed in real samples by stripping voltammetry were compared with GF-AAS, showing statistically similar values, demonstrating that GC/rGO could be effectively applied in the analysis of food samples.

Metallic air pollutants and breast cancer heterogeneity

BackgroundEmerging evidence suggests airborne metals may be associated with breast cancer risk. However, breast cancer is heterogenous and associations with heavy metals vary by subtype. Heavy metals possess both carcinogenic and xenoestrogenic properties which may be related to different tumor etiologies. Therefore, we tested for etiologic heterogeneity, using a case-series approach, to determine whether associations between residential airborne metal concentrations and breast cancer differed by tumor subtype. MethodsBetween 2005 and 2008, we enrolled incident breast cancer cases into the Breast Cancer Care in Chicago study. Tumor estrogen and progesterone receptors status was determined by medical record abstraction and confirmed immunohistochemically (N = 696; 147 ER/PR-negative). The 2002 USEPA's National Air Toxics Assessment census-tract estimates of metal concentrations (antimony, arsenic, beryllium, cadmium, chromium, cobalt, lead, manganese, mercury, nickel and selenium) were matched to participants' residences of the same year. Adjusted logistic regression models were used to examine whether the airborne heavy metal associations differed by tumor ER/PR status. Principal component analysis was performed to assess associations by metal co-exposures. ResultsComparing the highest and lowest quintiles, higher concentrations of antimony (odds ratio[OR]: 1.8, 95% confidence interval[CI]: 0.9, 3.7, P-trend: 0.05), cadmium (OR: 2.3, 95% CI: 1.2, 4.4, P-trend: 0.04) and cobalt (OR: 2.0, 95% CI: 0.9, 4.4, P-trend: 0.04) were associated with ER/PR-negative breast cancer. Mixture analysis using principal components suggested co-exposures to multiple airborne heavy metals may drive associations with tumor receptor status. ConclusionsAmong women diagnosed with breast cancer, metallic air pollutants were associated with increased odds of developing ER/PR-negative breast cancer.

Metallic AsSb nanoinclusions strongly enriched by Sb in AlGaAsSb metamaterial

We have elucidated the microstructure of Al0.28Ga0.72As0.972Sb0.028 metamaterial containing a developed array of AsSb nanoinclusions. The AlGaAsSb films were grown by low-temperature molecular-beam epitaxy followed by high-temperature postgrowth thermal treatment. The process resulted in an array of self-organized AsSb nanoinclusions with an average diameter of 15 nm (after annealing at 750 °C), which occupied about 0.003 of the volume of the crystalline AlGaAsSb matrix. The nanoinclusions were found to have an A7-type rhombohedral microstructure and contained a very high concentration of antimony that exceeded 90%, whereas the Sb content in the AlGaAsSb matrix was 2.8 at. %. The strong enrichment of the inclusion with Sb resulted from the local thermodynamic equilibrium between the solid AlGaAsSb matrix and the As0.1Sb0.9 inclusions that became liquid at an annealing temperature of 750 °C. The inclusion-matrix orientation relationship was established to be (003)p || {111}m and [2¯110]p || 〈220〉m, similar to that for pure As precipitates in low-temperature grown GaAs despite a rather large difference in particle lattice constants and the c/a ratio. The increased inclusion-matrix lattice mismatch resulted in the generation of (001) prismatic dislocation loops associated with the inclusions bigger than 8.5 nm in diameter. The Burgers vector of the dislocation was determined as b = amatrix[001]. The established microstructural and compositional features create an opportunity to specify plasmonic resonance conditions in the low-temperature grown AlGaAsSb metamaterial.

Selected Sorption Materials for Removal of Heavy Metals from Water

Increased pollution of water resources leads to deterioration of surface water and ground water quality and it initiates application of various methods for water treatment. Passing the Decree of the Ministry of Health of the Slovak Republic No. 247/20174 on requirements for drinking water and monitoring of drinking water quality have determined the limit of heavy metal concentrations in drinking water. Based on this fact some water resources in Slovakia became unsuitable for further use and they require appropriate treatment. The present research related to removal of heavy metals is focused on introduction of natural materials as well as industrial and agricultural waste that can be used as cost-effective sorption materials.Arsenic and antimony are present in the aquatic environment as result of rock weathering reactions, biological activity, geochemical reactions, volcanic emissions, mining operations and anthropogenic activities.The objective of this work was to verify the sorption properties of granular filter materials READ-As (hydrous cerium dioxide adsorbent) in removal of heavy metals from water. This material was developed in Japan for removal of arsenic from water. One part of experiments was carried out in ground water source Dúbrava, where a high concentration of antimony in water is caused from mining activities as well as from rain falling on antimony-rich waste rock piles and a sludge-settling pond has led to higher concentrations of antimony in the relevant water resources. At the other part of article there are presented results with the same material READ-As for removal of arsenic from ground water source in Jasenie. The values of the bed volume and the adsorption capacity for this sorption material when reaching the limit concentration of antimony and arsenic were determined. READ-As material has shown to be more efficient in antimony removal from water in Dúbrava locality than GEH, for average antimony concentrations of antimony in a raw water 27.73 μg/L, filtration rate 5.58 m/h reached the antimony concentration of 5 μg/L in the outflow from the adsorption column of high level 48 cm, V/Vo (bed volume) 3967 and adsorption capacity of a value 128.4 μg/g. Limit concentration of antimony 5 μg/L was exceeded after 336 hours of operation of the model equipment. Lower efficiency of the GEH material in Sb removal from the water was observed in consideration with currently published results. By pilot plant tests in Jasenie locality was determined adsorption capacity 354 μg/g and ration V/V0 (bed volume) 5130 μg/g for water with arsenic content of 55-60 μg/L and filtration rate 5.35 m/h, two steps filtration with READAs material. These values were determined when the limit concentration of arsenic in water outflowing the columns (10 μg/L) was reached. Mentioned values are significantly higher than it was in a case of antimony.

Chemical order in Ga or Sb modified germanium sulfide glasses around stoichiometry: High-resolution XPS and Raman studies

To understand the unique features of germanium sulfide (~60–70 at.% of S) glasses modified with Ga or Sb, the chemical order in these materials is investigated using X-ray photoelectron spectroscopy (XPS). The obtained results are correlated with Raman spectroscopy data and verified with quantum chemical calculations. It is shown that in addition to the regular corner-shared and SS-shared [SbS3/2] pyramids and [GeS4/2] tetrahedra, a fraction of these structural units can form edge-shared fragments. The obtained XPS results also support the possibility for [SbS5/2] distorted square pyramids formation in Sb-rich glasses. At higher concentrations of antimony, a tendency to the increased concentration of homopolar bonds is observed.

Antimony and arsenic exhibit contrasting spatial distributions in the sediment and vegetation of a contaminated wetland

Antimony is a priority environmental contaminant that is relatively poorly studied compared to other trace metal(loid)s. In particular, the behaviour of antimony in wetland sediments, where anaerobic conditions often dominate, has received considerably less attention compared to well-drained terrestrial soil environments. Here we report the results of a spatial assessment of antimony in the sediments and vegetation of a freshwater wetland exposed to stibnite tailings for the past forty years. The concentration of antimony in the sediment decreased rapidly with distance from the tailings deposit, from a maximum of ∼22,000 mg kg−1 to ∼1000 mg kg−1 at a distance of ∼150 m. In contrast, arsenic was distributed more evenly across the wetland, indicating that it was more mobile under the prevailing hypoxic/anoxic conditions. Less clear trends were observed in the tissues of wetland plants, with the concentrations of antimony in waterlilies (2.5–195 mg kg−1) showing no clear trends with distance from the tailings deposit, and no correlation with sediment concentrations. Sedges and Melaleuca sp. trees had lower antimony concentrations (<25 mg kg−1 and 5 mg kg−1, respectively) compared to waterlilies, but showed a non-significant trend of higher concentrations closer to the tailings. For all vegetation types sampled, antimony concentrations were consistently lower than arsenic concentrations (Sb:As = 0.27–0.31), despite higher concentrations of antimony in the sediment. Overall, the results of this study highlight clear differences in the behaviour of antimony and arsenic in freshwater wetlands, which should be considered during the management and remediation of such sites.

Effect of Antimony on Physiological Responses of Green Chinese Cabbage and Enzyme Activities of Allitic Udic Ferrisols

High concentrations of antimony (Sb) in soils and vegetables can cause potential health risk. However, the effect of Sb on the growth and response of crops are not well known and to date, there is still no Sb limit standard for Allitic Udic Ferrisols in China. In this study, a greenhouse experiment was carried out to investigate the effect of antimony (Sb) on biomass, physiological performances, and macro- and micronutrient element concentrations of green Chinese cabbage (Brassica chinensis L.), as well as enzyme activities, in Allitic Udic Ferrisols from Hunan Province, China. Antimony was supplied at rates of 0 (control), 2, 5, 10, 20, and 50 mg kg−1 and thus with the background value of 1.0 mg kg−1, the Sb concentrations in the treated soil samples were 1, 3, 6, 11 21, and 51 mg kg−1, respectively. The results showed the leaf biomass and ascorbic acid content of cabbage significantly (P < 0.05) decreased by 30.6% and 48.3%, respectively, and soil urease and dehydrogenase activities also significantly (P < 0.05) decreased by 33.6% and 32.5%, respectively, when soil Sb concentration was 21 mg kg−1 as compared with the control. The uptake of essential nutrient elements such as Mg, Cu, and Zn by cabbage was obviously affected, while the leaf soluble sugar content slightly changed when the soil Sb concentration exceeded 21 mg kg−1. Based on cabbage physiological responses and soil enzyme activities, the permissible concentration of 21 mg kg−1 for Sb in Allitic Udic Ferrisols should be recommended.

Antimony release in PET bottled natural water in Lebanon

Antimony (Sb) leaching from polyethylene terephthalate (PET) bottling material was assessed in eight registered Lebanese brands of bottled natural water as a function of contact time. The study was performed indoors at 22 °C in the dark and outdoors at a maximum temperature of 45 °C under sunlight. The leached antimony concentration increased with contact time for all of the studied brands except one. The antimony concentration reached 5.5 μg/L after 544 days of contact time with PET packaging. Small bottles with large contact surface area had higher antimony concentration. However, outdoor storage under sunlight at temperatures below 45 °C did not reveal a significant effect on antimony release. Among some physico-chemical parameters studied (pH, calcium, magnesium and bicarbonate), only calcium concentration showed a significant effect on antimony release. The rate of antimony leaching, normalized to the surface to volume ratio of the water bottle, fits the exponential model Sb/(S/V) = 0.562e0.0041t, with R2 = 0.87. Atomic absorption spectroscopy analysis of the different PET packaging material showed an antimony concentration between 80.6 and 352.7 mg Sb/kg PET.

Anodic behavior of Al–Bi and Al–Sb alloys in 3% NaCl solution

The methods of polarization curves and scanning electron microscopy are used to study the pitting corrosion resistance of Al-Bi (up to 4 wt.% Bi) and Al-Sb (up to 20 wt.% Sb) binary alloys in a 3% NaCl solution. With concentration of the alloying element to 0.1 wt.%, current density decreases and corrosion slows down. With higher concentrations of antimony and bismuth, the early passivation current density increases and the active region reduces on potentiodynamic curves. This indicates that the corrosion resistance of aluminum alloys decreases with greater content of the other phase (Bi or Sb).

Assessment of metal contaminations leaching out from recycling plastic bottles upon treatments

Heavy metal contaminants in environment, especially in drinking water, are always of great concern due to their health impact. Due to the use of heavy metals as catalysts during plastic syntheses, particularly antimony, human exposure to metal release from plastic bottles has been a serious concern in recent years. The aim and scope of this study were to assess metal contaminations leaching out from a series of recycling plastic bottles upon treatments. In this study, leaching concentrations of 16 metal elements were determined in 21 different types of plastic bottles from five commercial brands, which were made of recycling materials ranging from no. 1 to no. 7. Several sets of experiments were conducted to study the factors that could potentially affect the metal elements leaching from plastic bottles, which include cooling with frozen water, heating with boiling water, microwave, incubating with low-pH water, outdoor sunlight irradiation, and in-car storage. Heating and microwave can lead to a noticeable increase of antimony leaching relative to the controls in bottle samples A to G, and some even reached to a higher level than the maximum contamination level (MCL) of the US Environmental Protection Agency (USEPA) regulations. Incubation with low-pH water, outdoor sunlight irradiation, and in-car storage had no significant effect on antimony leaching relative to controls in bottle samples A to G, and the levels of antimony leaching detected were below 6 ppb which is the MCL of USEPA regulations. Cooling had almost no effect on antimony leaching based on our results. For the other interested 15 metal elements (Al, V, Cr, Mn, Co, Ni, Cu, As, Se, Mo, Ag, Cd, Ba, Tl, Pb), no significant leaching was detected or the level was far below the MCL of USEPA regulations in all bottle samples in this study. In addition, washing procedure did contribute to the antimony leaching concentration for polyethylene terephthalate (PET) bottles. The difference of antimony leaching concentration between washing procedure involved and no washing procedure involved (AC) was larger than zero for samples A to G. This interesting result showed that higher antimony concentration was detected in experiments with no washing procedures compared with those experiments with washing procedures. Our study results indicate that partial antimony leaching from PET bottles comes from contaminations on the surface of plastic during manufacturing process, while major antimony leaching comes from conditional changes. The results revealed that heating and microwaving enhance antimony leaching significantly in PET plastic bottles. Plastic bottle manufacturers should consider the contaminations during manufacturing process and washing bottles before first use was strongly recommended to remove those contaminants.

Antimony and arsenic leaching from secondary lead smelter air-pollution-control residues

Environments in the vicinity of the lead (Pb) smelters are contaminated by emissions containing high concentrations of antimony (Sb) and arsenic (As). Air-pollution-control (APC) residues from bag-type filters from a secondary Pb smelter were subjected to leaching experiments to elucidate the controlling mechanisms of Sb and As release. Kinetic batch leaching tests at a liquid-to-solid (L/S) ratio of 10 L kg(- 1) within the time frame of 720 hours and batch leaching at various L/S ratios (ranging from 1 to 1000 L kg(-1)) were performed. In contrast to other inorganic contaminants (Pb, Cd, Zn), less than 1% of the total Sb and As content was leached from the residues. At a L/S ratio of 10, the As and Sb concentrations in the leachates exceeded the EU limit values for non-hazardous waste (0.2 and 0.07 mg L(-1) ). According to PHREEQC-2 calculations, the concentrations of As and Sb are controlled by the precipitation of complex arsenates and antimonates mainly at low L/S ratios. The washing and related chemical/mineralogical transformation of APC residues was suggested as a technological pre-treatment process before their re-smelting in a blast furnace. The Ferrox-like processing of the resulting contaminated process water/leachate was simulated using the PHREEQC-2 code. Significant reduction was obtained in the concentration of some key contaminants (As, Cu, Pb, Zn) related to sorption on newly formed hydrous ferric oxides, whereas Sb and Cd exhibited only limited attenuation.

Antimony in the environment - the new global puzzle

Recent records in bogs[1] and Arctic polar ice cores[2] show a dramatic increase in antimony in the environment since the Industrial Revolution – probably because it is now being used extensively in industry[3] and for items such as car brake linings[4] and in fire retardants.[5] Air analyses in major cities show very high concentrations of antimony in air particulates,[6] and soil samples near motorways show enrichment in antimony.[7] As antimony has no known biological function, there is concern as to the long-term effects on ecosystems and humans from these increased levels. Many basic questions about the environmental chemistry of Sb remain unanswered, in particular, the factors that influence redox transformations in waters and soils and the formation of methylated species by organisms in landfills and sewage.[8–10] Its impact as an environmental contaminant is unclear and its toxicity to organisms is not well understood. Antimony is a global contaminant and there is an urgent need to improve our understanding of its biogeochemical cycling and behaviour, and risks associated with its presence in environmental systems. As well, data for environmental compartments such as groundwater[11,12] are sparse. It is clear that the natural biogeochemical cycle of Sb needs to be understood before the effects of global contamination can be assessed with confidence. It is timely to bring together a series of papers highlighting the biogeochemical cycling of Sb, its sources, transport through environmental compartments, and risk assessment. Thus, we present in the current Research Front a series of papers on various aspects of antimony’s environmental chemistry in order to enable readers to get some insight into the topic and its pressing issues. The series includes two Reviews, a Highlight article and five Research papers. Review articles Filella et al.[13] in their Review discuss the environmental chemistry of Sb, calling for more focussed research, particularly in the areas of ecotoxicology and speciation analysis.They ask that researchers carefully read the primary literature as myths about Sb are being propagated. A further Review from Tschan et al.[14] highlights that, although available soil Sb is readily taken up by plants, little is known about

Radiation effects on the optical properties of Se85−x Te15Sb x thin films

The optical absorption of the as-deposited and γ-irradiated (doses of 3, 10, 12, 15 Mrad) thermally evaporated Se85−x Te15Sb x (x=0, 6, 9) films was measured. The refractive index n and the extinction coefficient k of the films were calculated using an analytical method developed by Zheng et al. The Urbach relation was used in the fundamental edge region to calculate the width of the band tail states. The behavior of the composition with high concentration of antimony (x=9) was attributed to the produced Se–Sb bonds and an excess of Te–Te bonds, which break the chain structure of the Se–Te system and generate defects in the film. The related optical parameters were also calculated and discussed.

Occupational exposure to antimony compounds

The toxicology of antimony and its compounds is known from three sources: its medicinal use over centuries, studies of process workers in more recent times, and more recent still, studies of its presence in modern city environments and in domestic environments. Gross exposure to antimony compounds over long periods, usually the sulfide (SbS3) or the oxide (Sb2O3) has occurred in antimony miners and in antimony process workers. There have been relatively few of these, and few studies of possible symptoms have been made. Antimony sulfide imported from, at different times, China, South Africa, and South America was processed in the North-East of England from about 1870 to 2003. The process workers in North-East England have been studied at different times, notably by Sir Thomas Oliver in 1933, and by the Newcastle upon Tyne University Department of Occupational Medicine on later occasions. Studies which have been made of the working environment, and in particular of the risk of lung cancer in process workers, have underlined the high levels of exposure to antimony compounds and to other toxic materials. However, the working conditions in antimony processing have improved markedly over the last 30 years, and the workforce had been much reduced in numbers following automation of the process. Prior to the cessation of the industry in the UK it had become a 'white coat' operation with relatively few people exposed to high concentrations of antimony. Antimony, which is normally present in domestic environments, has also been studied as a possible cause of cot death syndrome (SIDS) but extensive investigations have not confirmed this. The full importance of environmental antimony has still to be determined, and evidence of specific effects has not yet been presented.

Antimony Enrichment on the Bullets' Surfaces and the Possibility of Finding It in Gunshot Residue (GSR) of the Ammunition Having Antimony-Free Primers

Abstract Projectiles of twenty brands of ammunition were examined by scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDX). In all of them antimony enrichment was found on the surface (about 10 µm depth or less) of the lead alloy as compared to the bulk. In some of the bullets the enrichment was high—as much as tens of times the bulk concentration. Concentration depth profiles in several of the projectiles were also studied by Auger electron spectroscopy (AES), and much higher concentrations of antimony on the surface than in the bulk were observed even where this effect could hardly be detected by SEM/EDX. Shooting tests were carried out using ammunition having antimony-free primers and in which the highest content of antimony on the surface of projectiles was observed. A very small percentage of gunshot residue particles containing antimony was found in these tests.

Antimony in the aquatic environment in north Kyushu district of Japan

In Japan, the water quality standards for items requiring surveillance for drinking water in 1992 and environmental water in 1993 stipulate that the concentration of antimony is 2 μg/l or less. Recently cases of water contamination by antimony have been reported throughout Japan. We have measured antimony concentrations in the aquatic environment in north Kyushu district of Japan by atomic absorption spectrometry with hydride generation and found them to be in the range 0.0 to 0.8 μg/l all of which were less than the water quality standards at the present time. However, wastewater containing high concentration of antimony may contaminate aquatic environment in future. Studies have since been carried out to remove antimony from polluted wastewater. We tried to use ferric chloride as coagulant and dechlorination tap water containing approximately 10 μg/l antimony as the sample solution. Of the sample solution, pH of which was 7 - 8 and included the ferric chloride, pH was controlled by adding either hydrochloric acid or sodium hydroxide. The efficiency of removal of antimony reached a maximum at pH 4.0 - 5.5. When ferric chloride concentration was more than 30 mg/l at pH 4.5, 80 - 90% antimony was removed. However, when the original antimony concentration was 250 μg/l, up to 200 mg/l ferric chloride had to be added. Therefore, from water originally polluted by antimony at concentrations of 2 - 250 μg/l, almost complete removal of antimony is expected by adding ferric chloride to become 200 mg/l and adjusting the pH to 4.5.

Antimony in the aquatic environment in North Kyushu district of Japan

In Japan, the water quality standards for items requiring surveillance for drinking water in 1992 and environmental water in 1993 stipulate that the concentration of antimony is 2 µg/l or less. Recently cases of water contamination by antimony have been reported throughout Japan. We have measured antimony concentrations in the aquatic environment in north Kyushu district of Japan by atomic absorption spectrometry with hydride generation and found them to be in the range 0.0 to 0.8 µg/l all of which were less than the water quality standards at the present time. However, wastewater containing high concentration of antimony may contaminate aquatic environment in future. Studies have since been carried out to remove antimony from polluted wastewater. We tried to use ferric chloride as coagulant and dechlorination tap water containing approximately 10 µg/l antimony as the sample solution. Of the sample solution, pH of which was 7 - 8 and included the ferric chloride, pH was controlled by adding either hydrochloric acid or sodium hydroxide. The efficiency of removal of antimony reached a maximum at pH 4.0 - 5.5. When ferric chloride concentration was more than 30 mg/l at pH 4.5, 80 - 90% antimony was removed. However, when the original antimony concentration was 250 µg/l, up to 200 mg/l ferric chloride had to be added. Therefore, from water originally polluted by antimony at concentrations of 2 - 250 µg/l, almost complete removal of antimony is expected by adding ferric chloride to become 200 mg/l and adjusting the pH to 4.5.