Antimony speciation as geochemical tracer for anthropogenic emissions of atmospheric particulate matter

Decryption analysis of antimony pollution sources in PM2.5 through a multi-source isotope mixing model based on lead isotopes

Antimony (Sb) in PM_2.5 has attracted close attention as a new air pollutant due to its extensive use in daily life. The identification of antimony sources in PM_2.5 by scientific methods is important to control its pollution. In this study, the Sb and other elements concentrations and Pb isotopic compositions in PM_2.5 and possible pollution sources (soil, road dust, traffic emission, coal-fired fly ash, local factory emission dust and cement dust) were analyzed. The results showed that the Sb in the PM_2.5 samples had seasonal change. The enrichment factors of Sb in PM_2.5 samples were all above 100 in four seasons, which indicated anthropogenic pollution. The average value of potential ecological risk index was at extremely high-risk level greater than 320. Based on Pearson correlation coefficient and hierarchical cluster analysis results, the pollution sources of antimony and lead in PM_2.5 samples were highly consistent which means that Pb isotopes might be a new and feasible tracer for Sb pollution in air. The sources analysis results based on Pb isotopes indicated that the proportion of Pb and Sb from coal-fired fly ash was the highest in winter (47.7%) and inclined to road dust in spring (34.5%), but it was mainly from traffic emissions in summer and autumn (34.2% and 32.8%). This study showed that Pb isotope tracing can be applied to predict the potential pollution sources, and it was also a feasible substitute for tracing Sb pollution in PM_2.5.

Fate of antimony contamination generated by road traffic - A focus on Sb geochemistry and speciation in stormwater ponds

Although antimony (Sb) contamination has been documented in urban areas, knowledge gaps remain concerning the contributions of the different sources to the Sb urban biogeochemical cycle, including non-exhaust road traffic emissions, urban materials leaching/erosion and waste incineration. Additionally, details are lacking about Sb chemical forms involved in urban soils, sediments and water bodies. Here, with the aim to document the fate of metallic contaminants emitted through non-exhaust traffic emissions in urban aquatic systems, we studied trace element contamination, with a particular focus on Sb geochemistry, in three highway stormwater pond systems, standing as models of surface environments receiving road-water runoff. In all systems, differentiated on the basis of lead isotopic signatures, Sb shows the higher enrichment factor with respect to the geochemical background, up to 130, compared to other traffic-related inorganic contaminants (Co, Cr, Ni, Cu, Zn, Cd, Pb). Measurements of Sb isotopic composition (δ¹²³Sb) performed on solid samples, including air-exposed dusts and underwater sediments, show an average signature of 0.07 ± 0.05‰ (n = 25, all sites), close to the δ¹²³Sb value measured previously in certified reference material of road dust (BCR 723, δ¹²³Sb = 0.03 ± 0.05‰). Moreover, a fractionation of Sb isotopes is observed between solid and dissolved phases in one sample, which might result from Sb (bio)reduction and/or adsorption processes. SEM-EDXS investigations show the presence of discrete submicrometric particles concentrating Sb in all the systems, interpreted as friction residues of Sb-containing brake pads. Sb solid speciation determined by linear combination fitting of X-Ray Absorption Near Edge Structure (XANES) spectra at the Sb K-edge shows an important spatial variability in the ponds, with Sb chemical forms likely driven by local redox conditions: "dry" samples exposed to air exhibited contributions from Sb(V)-O (52% to 100%) and Sb(III)-O (<10% to 48%) species whereas only underwater samples, representative of suboxic/anoxic conditions, showed an additional contribution from Sb(III)-S (41% to 80%) species. Altogether, these results confirm the traffic emission as a specific source of Sb emission in surface environments. The spatial variations of Sb speciation observed along the road-to-pond continuum likely reflect a high geochemical reactivity, which could have important implications on Sb transfer properties in (sub)surface hydrosystems.

Impact of the SARS-CoV-2 lockdown measures in Southern Spain on PM10 trace element and gaseous pollutant concentrations

Trace element concentrations within PM10, gaseous pollutants (NO₂ and SO₂), and PM10 levels were studied during the Covid-19 lockdown at a regional level in Southern Spain (Andalusia). Pollutant concentrations were compared considering different mobility periods (pre-lockdown, lockdown, and relaxation) in 2020 and previous years (2013-2016). An acute decrease in NO₂ levels (<50%) was observed as a consequence of traffic diminution during the confinement period. Moreover, a lower reduction in PM10 levels and a non-clear pattern for SO₂ levels were observed. During the lockdown period, PM10 elements released from traffic emissions (Sn and Sb) showed the highest concentration diminution in the study area. Regarding the primary industrial sites, there were no significant differences in V, Ni, La, and Cr concentration reduction during 2020 associated with industrial activity (stainless steel and oil refinery) in Algeciras Bay. Similarly, concentrations of Zn showed the same behaviour at Cordoba, indicating that the Zn-smelter activity was not affected by the lockdown. Nevertheless, stronger reductions of Cu, Zn, and As in Huelva during the confinement period indicated a decrease in the nearby Cu-smelter emissions. Brick factories in Bailen were also influenced by the confinement measures, as corroborated by the marked decrease in concentrations of Ni, V, Cu, and Zn during the lockdown compared to that from previous years. This work has shown the baseline concentrations of trace elements of PM10, which is of great value to air quality managers in order to minimise pollution levels by applying the confinement of the population, affecting both traffic and industrial anthropogenic activities.

Contribution of anthropogenic and natural sources in PM10 during North African dust events in Southern Europe

The influence of North African (NAF) dust events on the air quality at the regional level (12 representative monitoring stations) in Southern Europe during a long time series (2007-2014) was studied. PM10 levels and chemical composition were separated by Atlantic (ATL) and NAF air masses. An increase in the average PM10 concentrations was observed on sampling days with NAF dust influence (42 μg m^-3) when compared to ATL air masses (29 μg m^-3). Major compounds such as crustal components and secondary inorganic compounds (SIC), as well as toxic trace elements derived from industrial emissions, also showed higher concentrations of NAF events. A source contribution analysis using positive matrix factorisation (PMF) 5.0 of the PM10 chemical data, discriminating ATL and NAF air mass origins, allowed the identification of five sources: crustal, sea salt, traffic, regional, and industrial. A higher contribution (74%) of the natural sources to PM10 concentrations was confirmed under NAF episodes compared with ATL. Furthermore, there was an increase in anthropogenic sources during these events (51%), indicating the important influence of the NAF air masses on these sources. The results of this study highlight that environmental managers should take appropriate actions to reduce local emissions during NAF events to ensure good air quality.

Air quality biomonitoring through Olea europaea L.: The study case of "Land of pyres"

The "Land of pyres", namely "La Terra dei Fuochi", is an area of Campania region (South-Italy), highly inhabited and comprises between the Provinces of Naples and Caserta, sadly known worldwide for the criminal activities related to the illegal waste disposal and burning. These fires, concomitantly with traffic emissions, might be the source of potential toxic element (PTE) dangerous for the human health and causing pathologies. In the framework of Correlation Health-Environment project, funded by the Campania region, eight municipalities (of area "Land of pyres") and three remote sites have been bio-monitored using the olive (Olea europaea L.) plants as biomonitors. Leaves of olive plants were collected in each assayed municipality and the concentration of 11 metal(loid)s was evaluated by means of ICP-OES. Our findings revealed that the air of these municipalities was limitedly contaminated by PTE; in fact, only Sb, Al and Mn were detected in the olive leaves collected in some of the assayed municipalities and showed a high enrichment factors (EC) manly due, probably, to the vehicular traffic emissions. Furthermore, the concentrations of the other assayed PTEs were lower than those of Sb, Al and Mn. For these reasons we suppose that their emissions in the troposphere have been and are limited, and they mainly have a crustal origin. Even if our data are very comforting for those urban area, regarded by many as one of the most contaminated one in Italy, a great environment care, in any case, is always needed.

Characterizing the sources, concentrations and resuspension potential of metals and metalloids in the thoracic fraction of urban road dust

Road dust is a sink and source of metals and metalloids of human health concern. To date, many studies have examined the composition of road dust but there remain critical knowledge gaps on the chemistry of thoracic fractions (< 10 μm) and their patterns of deposition and resuspension. The goal of this study is to characterize the elemental concentrations and sources of thoracic fractions of road dust and their resuspension potential for Toronto, Ontario, Canada. Bulk and thoracic road sweepings were acid digested (HF, HClO₄, HNO₃ and HCl) and the elemental concentrations measured using ICP-MS. Principal component analysis (PCA) was applied to infer source emissions. Annual elemental loadings to roads were estimated using data on total sweepings collected by the City of Toronto. The mass amounts of metals and metalloids (< 10 μm) available for resuspension were calculated assuming a contribution of 10% to total loadings for this fraction. The median trace element concentrations in city sweepings (n = 64) ranged from highest to lowest as follows: Mn > Zn > Ba > Cr > Cu > Pb > V > Ni > Sn > Mo > Co > As > Sb > Cd. Iron, Cr, Ni, Co, Mo and Cu levels were significantly associated with road class, with the highest concentrations measured for the expressway. Most elements, especially Sb and Zn, were enriched in thoracic sweepings. The PCA results demonstrate the importance of non-fossil fuel, traffic-related elemental emissions. Difficulties in identifying sources, given uncertainties regarding overlapping chemical profiles, are also highlighted. Significant elemental loadings to roads were estimated to occur, with the largest amounts identified for Fe, Al, Mn, Zn, Cr and Cu. Road dust resuspension is predicted to be the most important source of emissions for Fe, Al, Mn, Cr, V, Sn, Mo, Co and Sb.

A Review on Atmospheric Analysis Focusing on Public Health, Environmental Legislation and Chemical Characterization

Atmospheric pollution has been considered one of the most important topics in environmental science once it can be related to the incidence of respiratory diseases, climate change, and others. Knowing the composition of this complex and variable mixture of gases and particulate matter is crucial to understand the damages it causes, help establish limit levels, reduce emissions, and mitigate risks. In this work, the current scenario of the legislation and guideline values for indoor and outdoor atmospheric parameters will be reviewed, focusing on the inorganic and organic compositions of particulate matter and on biomonitoring. Considering the concentration level of the contaminants in air and the physical aspects (meteorological conditions) involved in the dispersion of these contaminants, different approaches for air sampling and analysis have been developed in recent years. Finally, this review presents the importance of data analysis, whose main objective is to transform analytical results into reliable information about the significance of anthropic activities in air pollution and its possible sources. This information is a useful tool to help the government implement actions against atmospheric air pollution.

Characteristics, Accumulation, and Potential Health Risks of Antimony in Atmospheric Particulate Matter

Antimony (Sb), a priority pollutant listed by the U.S. Environmental Protection Agency (USEPA), can cause adverse effects on human health, with particular impacts on skin, eyes, gastrointestinal tract, and respiratory system. In this study, a database of Sb concentrations in the global atmosphere was developed through a survey of measurements published in more than 600 articles, which was then used to assess the health risks of Sb exposure based on a USEPA assessment model. Most measurements showed Sb concentrations of less than ∼10 ng m-3, but those at several contaminated sites exhibited Sb concentrations of more than 100 ng m-3. For measurements conducted in urban environments, Sb concentrations in the total suspended particles (TSP) and particles of less than 10 (PM10) or 2.5 μm (PM2.5) were the highest in Asia, followed by Europe, South America, and North America. Sb concentrations were generally higher in winter and fall than during other seasons in TSP and PM10 samples. A significant correlation was observed between Sb and As in TSP and PM2.5 on a global scale. Sb was mainly derived from anthropogenic sources, especially traffic emission, industrial emission, and fossil combustion. Hazard quotients (HQ) of Sb in TSP, PM10, and PM2.5 were higher for children than adults because of their lighter body weight, inferior physical resistance, and higher ingestion probability. The global database for atmospheric Sb concentrations demonstrates a relatively low noncarcinogenic risk in most regions. Long-term monitoring is still required to identify the sources and growth potentials of Sb so that effective control policies can be established.

Ecotoxicology of Heavy Metal(loid)-Enriched Particulate Matter: Foliar Accumulation by Plants and Health Impacts

Atmospheric contamination by heavy metal-enriched particulate matter (metal-PM) is highly topical nowadays because of its high persistence and toxic nature. Metal-PMs are emitted to the atmosphere by various natural and anthropogenic activities, the latter being the major source. After being released into the atmosphere, metal-PM can travel over a long distance and can deposit on the buildings, water, soil, and plant canopy. In this way, these metal-PMs can contaminate different parts of the ecosystem. In addition, metal-PMs can be directly inhaled by humans and induce several health effects. Therefore, it is of great importance to understand the fate and behavior of these metal-PMs in the environment. In this review, we highlighted the atmospheric contamination by metal-PMs, possible sources, speciation, transport over a long distance, and deposition on soil, plants, and buildings. This review also describes the foliar deposition and uptake of metal-PMs by plants. Moreover, the inhalation of these metal-PMs by humans and the associated health risks have been critically discussed. Finally, the article proposed some key management strategies and future perspectives along with the summary of the entire review. The abovementioned facts about the biogeochemical behavior of metal-PMs in the ecosystem have been supported with well-summarized tables (total 14) and figures (4), which make this review article highly informative and useful for researchers, scientists, students, policymakers, and the organizations involved in development and management. It is proposed that management strategies should be developed and adapted to cope with atmospheric release and contamination of metal-PM.

Determination of oxoanions and water-soluble species of arsenic, selenium, antimony, vanadium, and chromium eluted in water from airborne fine particles (PM2.5): effect of acid and transition metal content of particles on heavy metal elution

Heavy metals in particulate matter (PM) are of great concern, and their effects on the environment and human health depend on their solubilities and species present. In this study, the solubility of As, Se, Sb, V and Cr and their species eluted in water was investigated. As, Se, Sb, and V were present mostly in fine particles, and they were predominantly water-soluble in fine particles (<2.5 μm, PM_2.5) but insoluble in coarse particles (>2.5 μm). Solubility of Cr was poor even in fine particles. It was found that for fine particles, solubilities of the heavy metals were related to the nitrate and sulfate contents. This suggests that the higher the acidity of the particles, the higher the solubility of the heavy metals. Oxoanions of the five kinds of heavy metals in water extracts of fine particles were determined by inductively coupled plasma mass spectrometry preceded by ion chromatography. The results suggested the presence of atmospheric oxidation during the aerosol transportation. Also, the As(iii)/As(v) (arsenite/arsenate) ratios for the fine particle extracts were related to the transition metal concentrations, which indicated that Fe, Cu, etc. in fine particles affected the As redox equilibrium. It was suggested that the heavy metals exist as complexes with iron hydroxide and dissolved organic matter in addition to the free oxoanions. These investigations were performed for PM samples collected in winter and summer in Kumamoto, west Japan, where the site is strongly exposed to westerly winds from continental East Asia. The obtained results improve our understanding of the behavior of the heavy metals in airborne PM after depositing on a wet environment and biota.

Multidisciplinary Approach for Evaluating the Geochemical Degradation of Building Stone Related to Pollution Sources in the Historical Center of Naples (Italy)

Natural stones have represented one of the main building materials since ancient times. In recent decades, a worsening in degradation phenomena related mostly to environmental pollution was observed, threatening their conservation. The present work is focused on the minero-petrographic and geochemical characterization of black crust (BC) samples taken from the historical center of Naples, after selecting two pilot monumental areas. The latter were chosen based on their historical importance, type of material, state of preservation and position in the urban context (i.e., high vehicular traffic area, limited traffic area, industrial area, etc.). The building materials used and their interaction with environmental pollutions were studied comparing the results obtained by means of different analytical techniques such as polarized light Optical Microscopy (OM), scanning electron microscopy with energy dispersion system (SEM-EDS), X-ray powder diffraction (XRPD) and laser ablation coupled with inductive plasma mass spectrometry (LA-ICP-MS).

Chemical characterization of mountain forest soils: impact of long-term atmospheric deposition loadings (Czech-Polish-German border region)

The composition of lipids in soil offers clues to soil degradation processes due their persistency and selectivity in soil, and close relation to long-term processes in the ecosystem, thanks to their role in cell membranes of organisms. Organic solvent-extractable compounds were recovered from soils collected at two sites differing in the degree of forest damage. Gas chromatography/mass spectroscopy and Fourier transform infrared spectroscopy were applied in order to characterize solvent-extractable lipids. Raman spectroscopy was also applied as it provides distinct advantages for determining the structural order of carbonaceous materials. The organic matter measurement techniques were combined with an established simultaneous multi-element measurement technique. Variations in individual soil horizons from the sites were reflected in the crystallinity of epicuticular waxes, presence of long-chain aliphatic hydrocarbons, concentrations of n-alkanes, saturated and unsaturated fatty acids, dicarboxylic acids, and in the content of aromatic structures, hydroxyl, ester, and carboxylic acid groups. The results are explained by differently transformed organic matter. The concentrations of elements in the soils were also affected by atmospheric depositions, including higher accumulations of arsenic and antimony, and lower contents of natural nutrients. These data have potential to be used as sensitive biogenic indicators of ecosystem damage by long-term atmospheric depositions.

A review of removal technology for antimony in aqueous solution

Antimony (Sb) and its compounds, toxic metalloid, have been classified as high-priority pollutants. Increasing Sb released into the water environment by natural processes and anthropogenic activities, which exposure threatens to human health and ecosystems. Therefore, it is of unquestionable importance to remove Sb from polluted water. Keeping in view the extreme importance of this issue, we summarize the source, chemistry, speciation, distribution, toxicity, and polluted situation of Sb about aqueous solution. Then, we provide the recent and common technology to remove Sb, which are based on adsorption, coagulation/flocculation, electrochemical technology, membrane technology, ion exchange, etc. In this review, we focus in detail on the adsorption method, researchers at present have been investigating to discover more advanced, cost-effective, eco-friendly, reusable adsorbents. However, to date the Sb-containing wastewater treatment technologies are not sufficiently developed and most of research have been tested only in controlled lab conditions. Few reports are available that include field studies and applications. We critically analyzed the salient features and removal mechanisms, evaluating benefits and limitations of these technologies, hoping to provide more references for further research. Finally, we considered the Fe- or Mn-based technologies was the most promising technique to remove Sb for field application.

Hazardous trace elements in thoracic fraction of airborne particulate matter: Assessment of temporal variations, sources, and health risks in a megacity

The deleterious health effects of thoracic fractions seem to be more related to the chemical composition of the particles than to their mass concentration. The presence of hazardous materials in PM₁₀ (e.g., heavy metals and metalloids) causes risks to human health. In this study, twelve trace elements (Cd, Cr, Pb, Zn, Cu, Ni, Sn, Ba, Co, As, V, and Sb) in 315 samples of ambient PM₁₀ were analyzed. The samples were collected at an urban background site in a Latin American megacity (Bogota, Colombia) for one year. The concentrations and temporal variabilities of these elements were examined. According to the results, Cu (52 ng/m³), Zn (44 ng/m³), Pb (25 ng/m³), and Ba (20 ng/m³) were the traces with the highest concentrations, particularly during the dry season (January to March), which was characterized by barbecue (BBQ) charcoal combustion and forest fires. In addition, the differences between the results of weekdays and weekends were identified. The determined enrichment factor (EF) indicated that Zn, Pb, Sn, Cu, Cd, and Sb mainly originated from anthropogenic sources. Moreover, a speciation analysis of inorganic Sb (EF > 300) was conducted, which revealed that Sb(V) was the main Sb species in the PM₁₀ samples (>80%). Six causes for the hazardous elements were identified based on the positive matrix factorization (PMF) model: fossil fuel combustion and forest fires (60%), road dust (19%), traffic-related emissions (9%), copper smelting (8%), the iron and steel industry (2%), and an unidentified industrial sector (2%). Furthermore, a health risk assessment of the carcinogenic elements was performed. Accordingly, the cancer risk of inhalation exposure to Co, Ni, As, Cd, Sb(III), and Pb was negligible for children and adults at the sampling site. For adults, the adjusted Cr(VI) level was slightly higher than the minimal acceptable risk level during the study period (1.4 × 10^-6).

Anthropogenic and meteorological influences on PM10 metal/semi-metal concentrations: Implications for human health

There is growing interest in investigating the human health risk associated with metals in airborne particulate matter. The objective of this paper is the health risk assessment of Al, Be, Sb, Sn, Ti and Tl in PM₁₀ under different advections of air masses. These metals/semi-metal were studied in samples collected in an area influenced by industrial activities in northern Spain with the aim of analysing the variations in PM₁₀ metal/semi-metal. Elemental concentrations were assessed over a period of one year in terms of air mass origin by means of back trajectories (HYSPLIT), the conditional probability function, polar plots, PM concentration roses, aerosol maps (NAAPs) and receptor modelling. The mean concentrations of Al, Be, Sb, Sn, Ti and Tl were 254, 0.02, 1.30, 1.15, 15.3 and 0.20  ng/m³, respectively, and were within the usual range for suburban stations in Europe. The highest levels were recorded during conditions of regional air mass origin, highlighting the importance of sources not far from the station. Under these circumstances, the renovation of air masses was not produced. The main sources of metals were anthropogenic, mostly related to the use of coal and coke production. In general, the cancer and non-cancer risk values obtained in this study fell within accepted precautionary criteria in all trajectory groups. However, in order to improve air quality and reduce risks to human health, the impact resulting from the joint inhalation of Al, Be, Sb, Sn, Ti and Tl should not be ignored when air masses are fundamentally of regional origin.

The source apportionment, pollution characteristic and mobility of Sb in roadside soils affected by traffic and industrial activities

Antimony (Sb), as an emerging pollutant, has aroused people's concerns for its wide usage in industrial production. In this study, we identify and quantify the traffic-derived Sb and investigate its mobility in roadside soils affected by traffic and industrial activities. 73 surface roadside soils and 5 transects in three areas nearby different industries (smelting, power and refining, and waste incineration) were collected and analyzed. Results showed that the Sb concentration ranged between 0.54 and 9.32 mg/kg, and the mean EF_s value was 4.63, which indicated moderate to significant Sb enrichment. Significantly high concentrations of Sb occurred at locations with heavy traffic and frequent braking process, with an average concentration of 4.13 mg/kg, compared to the control sites (2.01 mg/kg). Moreover, Sb diffused exponentially with increasing distance from road edges. These results suggested that traffic activities were the main source of Sb in roadside soils. According to the quantitative calculation, the average contributions from traffic, industrial activities and soil parent material to Sb accumulation in roadside soils were 50.73%, 21.38% and 27.88%, respectively. Even though Sb was slightly mobile, roadside soils was a persistent source of potentially mobile Sb which may release into water and cause long-term environmental risk.

Removal of antimonite and antimonate from water using Fe-based metal-organic frameworks: The relationship between framework structure and adsorption performance

We investigated the adsorption performance of five Fe-based MOFs (Fe-BTC, MIL-100(Fe), MIL-101(Fe), MIL-53(Fe) and MIL-88C(Fe)) for removal of antimonite (Sb(III)) and antimonate (Sb(V)) from water. Among these MOFs, MIL-101(Fe) exhibited the best adsorption capacities for both Sb(III) and Sb(V) (151.8 and 472.8mg/g, respectively) which were higher than those of most adsorbents previously reported. The effect of steric hindrance was evident during Sb removal using the Fe-based MOFs, and the proper diameter of the smallest cage windows/channels should be considered an important parameter during the evaluation and selection of MOFs. Additionally, the adsorption capacities of MIL-101(Fe) for Sb(V) decreased with increasing initial pH values (from 3.0 to 8.0), while the opposite trend was observed for Sb(III). Chloride, nitrate and sulfate ions had a negligible influence on Sb(V) adsorption, while NO₃^- and SO₄^2- improved Sb(III) adsorption. This result implies that inner sphere complexes might form during both Sb(III) and Sb(V) adsorption.

Sequential determination and chemical speciation analysis of inorganic As and Sb in airborne particulate matter collected in outdoor and indoor environments using slurry sampling and detection by HG AAS

In this work, fast sequential determination and chemical speciation analysis of inorganic arsenic and antimony in airborne particulate matter collected in outdoor and indoor environments using slurry sampling and detection by hydride generation atomic absorption spectrometry (HG-AAS) is proposed. A Doehlert design was applied to optimise the hydride generation conditions of As and Sb for fast sequential determination in the same aliquot of particulate matter samples after preparation of the slurry. The limits of quantification (LoQ) obtained for As and Sb were 0.3 and 0.9 ng m^-3, respectively. The accuracy of the analytical method was confirmed by analysis of the certified reference material of urban particulate matter (SRM NIST 1648a), presenting concordance with certified values of 92.7±7.7% for As and 91.2±9.5% for Sb. Precision was expressed as relative standard deviation (% RSD, n=3), with our results presenting values better than 3.4% and 4.2% for total inorganic As and Sb, respectively. For all analysed samples, total As concentrations and its inorganic species were below the LoQ of the analytical method (<0.3 ng m^-3). However, the averages of total inorganic Sb concentrations in airborne particulate matter, collected as total suspended outdoor particles (TSP_outdoor), inhalable particulate matter (PM₁₀), and total suspended indoor particles (TSP_indoor), were 3.1±0.5, 2.4±0.6, and 2.6±0.4 ng m^-3, respectively. Trivalent Sb (Sb³⁺) was the predominant inorganic species in all samples investigated, with mean percentages of 76%, 72%, and 73% in TSP_outdoor, PM₁₀, and TSP_indoor, respectively. The presence of Sb and its predominant inorganic form (Sb³⁺) can be attributed to vehicular traffic close to the sampled urban areas. Therefore, fast sequential determination of As and Sb and their inorganic species in particulate matter samples prepared as slurry by FS-HG-AAS is an efficient, accurate, and precise method and can be successfully applied to routine analysis.

Antimony speciation in the environment: Recent advances in understanding the biogeochemical processes and ecological effects

Antimony (Sb) is a toxic metalloid, and its pollution has become a global environmental problem as a result of its extensive use and corresponding Sb-mining activities. The toxicity and mobility of Sb strongly depend on its chemical speciation. In this review, we summarize the current knowledge on the biogeochemical processes (including emission, distribution, speciation, redox, metabolism and toxicity) that trigger the mobilization and transformation of Sb from pollution sources to the surrounding environment. Natural phenomena such as weathering, biological activity and volcanic activity, together with anthropogenic inputs, are responsible for the emission of Sb into the environment. Sb emitted in the environment can adsorb and undergo redox reactions on organic or inorganic environmental media, thus changing its existing form and exerting toxic effects on the ecosystem. This review is based on a careful and systematic collection of the latest papers during 2010-2017 and our research results, and it illustrates the fate and ecological effects of Sb in the environment.

Integrated approach to environmental pollution investigation - Spatial and temporal patterns of potentially toxic elements and magnetic particles in vineyard through the entire grapevine season

An integrated approach to the investigation of potentially toxic elements (PTEs) was applied to the soil and grapevine leaf samples collected from vineyard environment through the grapevine season. To investigate mobile and bioavailable concentrations of PTEs, six single extraction procedures and pseudo-total digestion were applied to the samples. The element concentrations in the samples were measured using inductively coupled plasma-optical emission spectrometry (ICP-OES) and inductively coupled plasma-mass spectrometry (ICP-MS). To assess atmospheric particle deposition, saturation isothermal remanent magnetisation (SIRM) was applied to the leaf samples. The obtained PTE concentrations in samples were used for calculating various ecological implications in the vineyard environment. The notable environmental pollution implications were estimated for As, B, Cd, Co, Cr, Cu, Mn, Ni and Sr. The environmental risk (RI) of the elements soluble under low-acid conditions influenced soil bioavailability risk. The most bioavailable elements from soil to leaves were Mn, Ni and Sr, followed by Cr and Cu. Cadmium and Co were strongly-bonded in the soil and were not bioavailable. The most suitable extractants for assessing bioavailability in the soil-leaf system were chelating agent Na₂EDTA, and weak salt solutions CaCl₂ and NH₄NO₃. The biological accumulation concentrations (BACs) of B, Ba, Cd, Co, Ni and Zn were decreasing in the leaves through the grapevine growing phases, that is contributed to the decreasing agrochemical application through the season. The BACs of Co, Cr, Sb and Pb, in July (veraison), were higher than in other phases, which indicate anthropogenic activities. According to correlations between biogeochemical index (BGI) and BAC, Cu and Na were mostly bioaccumulated from soil to leaves due to agrochemical applications, while bioaccumulation of B, Cd, Sb and Sr could be influenced by the other anthropogenic sources. Significant correlations between PTE concentrations and SIRM imply that leaves indicate Co, Cr and Ni air pollution in the vineyard environment.

Enrichment and sources of trace metals in roadside soils in Shanghai, China: A case study of two urban/rural roads

The road traffic has become one of the main sources of urban pollution and could directly affect roadside soils. To understand the level of contamination and potential sources of trace metals in roadside soils of Shanghai, 10 trace metals (Sb, Cr, Co, Ni, Cu, Cd, Pb, Hg, Mn and Zn) from two urban/rural roads (Hutai Road and Wunign-Caoan Road) were analyzed in this study. Antimony, Ni, Cu, Cd, Pb, Hg and Zn concentrations were higher than that of soil background values of Shanghai, whereas accumulation of Cr, Co and Mn were minimal. Significantly higher Sb, Cd, Pb contents were found in samples from urban areas than those from suburban area, suggesting the impact from urbanization. The concentrations of Sb and Cd in older road (Hutai) were higher than that in younger road (Wunign-Caoan). Multivariate statistical analysis revealed that Sb, Cu, Cd, Pb and Zn were mainly controlled by traffic activities (e.g. brake wear, tire wear, automobile exhaust) with high contamination levels found near traffic-intensive areas; Cr, Co, Ni and Mn derived primarily from soil parent materials; Hg was related to industrial activities. Besides, the enrichment of Sb, Cd, Cu, Pb and Zn showed a decreasing trend with distance to the road edges. According to the enrichment factors (EF_s), 78.5% of Sb, Cu, Cd, Pb and Zn were in moderate or significant pollution, indicating considerable traffic contribution. In particular, recently introduced in automotive technology, accumulation of Sb has been recognized in 42.9% samples of both roads. The accumulation of these traffic-derived metals causes potential negative impact to human health and ecological environment and should be concerned, especially the emerging trace elements like Sb.

Characterization of typical metal particles during haze episodes in Shanghai, China

Aerosol particles were collected during three heavy haze episodes at Shanghai in the winter of 2013. Transmission electron microscopy (TEM) coupled with energy dispersive X-ray spectroscopy was used to study the morphology and speciation of typical metal particles at a single-particle level. In addition, time-of-flight aerosol mass spectrometry (ATOFMS) was applied to identify the speciation of the Fe-containing particles. TEM analysis indicated that various metal-containing particles were hosted by sulfates, nitrates, and oxides. Fe-bearing particles mainly originated from vehicle emissions and/or steel production. Pb-, Zn-, and Sb-bearing particles were mainly contributed by anthropogenic sources. Fe-bearing particles were clustered into six groups by ATOFMS: Fe-Carbon, Fe-Inorganic, Fe-Trace metal, Fe-CN, Fe-PO_3, and Fe-NO₃. ATOFMS data suggested that Fe-containing particles corresponded to different origins, including industrial activities, resuspension of dusts, and vehicle emissions. Fe-Carbon and Fe-CN particles displayed significant diurnal variation, and high levels were observed during the morning rush hours. Fe-Inorganic and Fe-Trace metal particle levels peaked at night. Furthermore, Fe-Carbon and Fe-PO₃ were mainly concentrated in the fine particles. Fe-CN, Fe-Inorganic, and Fe-Trace metal exhibited bimodal distribution. The mixing state of the particles revealed that all Fe-bearing particles tended to be mixed with sulfate and nitrate. The data presented herein is essential for elucidating the origin, evolution processes, and health effects of metal-bearing particles.