Elemental and magnetic analyses, source identification, and oxidative potential of airborne, passive, and street dust particles in Asaluyeh County, Iran

Rare earth elements and health risk assessment of road dust from the vicinity of coal fired thermal power plants

As emerging pollutants, rare earth elements (REEs) have been explored in different environmental samples. This is the first study to use road dust samples to monitor REEs form the vicinity of thermal power plant (TPPs). Road dust samples were collected from 17 locations (main and side roads) in a 15 km radius surrounding two coal-fired TPP (TPP Kostolac A & B, Serbia). Concentrations of nine REEs (Sc, La, Ce, Nd, Sm, Eu, Tb, Dy, Yb) were measured in the road dust samples (f < 63 μm, easily resuspended fraction size) using instrumental neutron activation analysis (INAA). We have found that the concentrations of REEs do not depend on the distance of the sampling location from TPP. There were no statistically significant differences between the main road and side road samples suggest that traffic is not the main source of REE in the studied area. Principal component analysis, hierarchical cluster analysis as well as geo-accumulation index (Igeo) and enrichment factors (EF) point to an enrichment with Dy of road dust samples collected in September. The road dust samples do not pose any harm to human health in the tested area, as shown by a hazard index of less than 0.1. Despite the low REE risk, it is important to consider the possibility of negative health consequences, mainly because these samples may contain numerous other organic and inorganic pollutants.

Characterization of PM2.5 emissions from on-road vehicles in the tunnel of a major Middle Eastern city

Traffic emissions are an important source of air pollution worldwide, but in the Middle East, this problem is exacerbated by weak or no enforcement of emission regulations. Comprehensive measurements of fine PM emission factors (EFs) from road transport in the region have not yet been conducted, but such data are necessary for quantitative assessments of the health impact of transport emissions in the region. To address this need, PM2.5 samples collected inside the Salim Slam tunnel in Beirut, Lebanon were analyzed for carbonaceous matter (organic carbon (OC) and elemental carbon (EC)), water-soluble ions, elements, and selected organic compounds. The OC/EC ratio was 1.8 for the total fleet and 2.6 for light-duty vehicles (LDV), in agreement with the dominant proportion of gasoline LDV in the Lebanese fleet. A Cu/Sb ratio of 4.2 ± 0.1 was observed, offering a valuable metric for detecting brake wear emissions in subsequent studies conducted in the region. The EFs of carbonaceous matter, elements and ions generally varied by a factor 0.1 and 10 in comparison to literature values, while those for alkanes and polycyclic aromatic hydrocarbons were similar to the upper values previously reported. The average number size distribution was characterized by a single mode around 35 nm. The particles number EF (for diameters between 10 and 480 nm) was within the range of 1014-1015 particles per kg of fuel. The chemical mass balance model showed an average contribution to EF of 62% from non-exhaust sources. This study highlights the need for more enforceable stringent vehicular regulations because of the local practices (i.e., removal of catalyst) and some EF values are very high compared to other studies/countries.

On the nature and sources of microplastics (MPs) and microrubbers (MRs) in urban snow

This work reports a characterization of microplastics (MPs) and microrubbers (MRs) such as color, size, shape, and the chemical composition in snowfall in central Iran (Qom) at five sites. Identification of MPs and MRs involved using a stereo microscope to evaluate physical characteristics such as thickness, shininess, hardness, and reaction to a hot needle. HYSPLIT trajectory and end-member microplastic (PM) mixing models are used to determine the contribution of local and remote sources to MPs. The mean (±SD) abundance of MPs and MRs is 23.8 ± 15.87 (MP/L) and 1.26 ± 1.16 (MR/L), respectively, whereas the mean (±SD) abundance of MPs and MRs is 30.7 ± 19.36 (MP/m2) and 1.58 ± 1.39 (MR/m2), respectively. The frequency of MP colors in order are: black (63.8%) > red (12.8%) > blue (11 %) > white (9.1%) > green (2.1%) > yellow (1.3%). About 71.6% and 3.6% of the identified MPs are 250-500 μm and >1000 μm, respectively. Snow samples contain different identified polymers such as polyethylene terephthalate (PET), nylon, viscose, polypropylene (PP), polyethylene (PE), polystyrene (PS), and polyvinyl chloride (PVC). Analysis reveals that 90% of Qom city's snowy day winds come from local sources. The high MP levels in are due to human activities from local origins according to end-member MP mixing model. Further study is needed to understand the potential impacts of MPs and MRs on ecosystems and human health.

Evaluation of potentially toxic elements and microplastics in the water treatment facility

The potentially harmful effects of consuming potentially toxic elements (PTEs) and microplastics (MPs) regularly via drinking water are a significant cause for worry. This study investigated PTEs (Cd, Cu, Cr, Ni, Pd, Zn, Co), MPs, turbidity, pH, conductivity, and health risk assessment in the water treatment plant in Kielce, Poland. Zn had the highest concentrations throughout the water treatment facility, whereas Cd, Pb, and Co had lower concentrations (< 0.1 µg/L). The order of the concentrations among the specified PTEs was like Zn˃Cu˃Ni˃Cr˃Cd˃Pb and Co. The minimum turbidity was 0.34, and the maximum was 1.9 NTU. The range of pH in water samples was 6.51-7.47. The conductivity was 1,203-1,445 ms in water samples. These identified MPs were categorized into fiber and fragments. The color of these identified MPs was blue, red, black, green, and transparent. The minimum and maximum size of the MPs was 196 and 4,018 µm, while the average size was 2,751 ± 1,905 µm. The average concentration of MPs per liter of the water treatment plant was 108.88 ± 55.61. The elements listed are C, O, Na, Mg, Al, Si, K, Ca, and Ti. Fe and Zn were the predominant elements seen using EDX. HQ values of the PTEs were less than one for adults and children. The human health risk associated with all detected PTEs revealed that the HQ values exhibit a satisfactory degree of non-carcinogenic adverse health risk. HI values for adults and children age groups were less than one. In most water treatment samples, the carcinogenic value exceeds the threshold value of 10-6. The PTEs and MP concentrations in drinking water should be periodically monitored to minimize consumers' environmental pollution and health risks.

Accumulation, sources, and health risks of phthalic acid esters (PAEs) in road dust from heavily industrialized, urban and rural areas in southern Iran

In this research, a total of 51 road dust samples were collected from three districts (Asaluyeh, Bushehr, and Goshoui) in the south of Iran from April to June 2022 and analyzed for the concentration of 7 phthalic acid esters (PAEs) compounds. Asaluyeh was considered as an industrial area (near gas and petrochemical industries), Bushehr as an urban area, and Goshoui as a rural area (far from pollution sources). The PAEs concentration of the street dust samples was determined using a mass detection gas chromatography (GC/MS). The mean ± SD levels of ƩPAEs in samples from industrial, urban, and rural sources were 56.9 ± 11.5, 18.3 ± 9.64, and 5.68 ± 1.85 μg/g, respectively. The mean concentration levels of ƩPAEs was significantly (P < 0.05) higher in samples from the industrial area than urban and rural areas. The mean levels of di(2-Ethylhexyl) phthalate (DEHP) in industrial, urban, and rural areas were 20.3 ± 8.76, 4.59 ± 1.71, and 2.35 ± 0.98 μg/g, respectively. The results of the PCA analysis indicate that the likely major sources of PAEs in the road dust in the studied areas are the application of various plasticizers in industry, solvents, chemical fertilizers, waste disposal, wastewater (e.g., agricultural, domestic, and industrial), and the use of plastic films and plastic-based irrigation pipes in greenhouses. As well as, it was found that the non-cancer risk of exposure to dust-bound PAEs was higher for children than for adults. These values were <1 for both age groups (children and adults) and the exposure of inhabitants to PAEs in road dust did not pose a notable non-cancer risk. The cancer risk from exposure to DEHP in road dust was below the standard range of 10-6 in all three areas. Further studies that consider different routes of exposure to these contaminants are needed for an accurate risk assessment. Moreover, since higher PAEs level was found in industrial area, decision-makers should adopt strict strategies to control the discharging of pollution from industries to the environment and human societies.

Spatial distribution, sources identification, and health risk assessment polycyclic aromatic hydrocarbon compounds and polychlorinated biphenyl compounds in total suspended particulates (TSP) in the air of South Pars Industrial region-Iran

South Pars Industrial Energy Zone, located in the southwest of Iran along the Persian Gulf coast, encompasses many industrial units in the vicinity of urban areas. This research study investigated the effects of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) on human health and the environment. Suspended particulate matters (SPM) in the air sampled, in summer and winter 2019, from ten stations next to industrial units and residential areas. The samples were analyzed by gas chromatography-mass spectrometry (GC-MS). Spatial distribution maps of pollutants in the region were prepared using GIS software. The highest carcinogenic risk due to PAHs and PCBs measured as ([Formula: see text]) and ([Formula: see text], respectively. According to the US Environmental Protection Agency limit ([Formula: see text]), the cancer risks from PAH compounds were significant and need further investigation. The PCB cancer risks were within acceptable ranges. The highest adsorption ratios for PAHs were obtained through skin and PCBs by ingestion. The maximum measured non-carcinogenic hazard indexes (HI) turned out to be 0.037 and 0.023 for PAH and PCB, respectively, and were reported as acceptable risks. The predominant source of PAH in industrial areas was liquid fossil combustion, and in urban areas replaced by coal-wood-sugarcane combustion. Petrochemical complexes, flares, power plants (69%), electric waste disposal sites, and commercial pigments (31%) were reported as PCB sources. Industries activities were the most effective factors in producing the highest level of carcinogenic compounds in the region, and it is necessary to include essential measures in the reform programs.

Environmental magnetic signatures in mangrove ecosystems in northern Persian Gulf: Implication for pollution assessment in marine environment

Magnetic properties of root, bark, and leaf of mangrove (Avicenna marina) and sediment were determined for pollution assessment at three locations in the northern coast of the Persian Gulf. The study revealed that the sources of the particles deposited on leaf surfaces can be discriminated via saturation isothermal remanent magnetization (SIRM) values and heavy metal. However, different factors including wind direction, size of the magnetic particles and crown density, play a role using SIRM for biomonitoring of atmospheric particulate matter. For leaves, the significant correlations between SIRM and leaf elemental contents indicated that the deposited particles on their surface mainly have geogenic sources. The magnetic analyses revealed that leaves are more suitable than bark for monitoring atmospheric pollution using mangrove trees due to the effect of different factors including dense crown of trees, washing of tree trunk by sea waves, and elements translocation from roots and sediments. Instead, the positive and significant correlation between the SIRM values for sediments and mangrove roots, and no or negative correlation between sediments and roots with barks and leaves indicates that the magnetic properties of the sediments and mangrove roots are suitable indicators of pollution in aquatic environment.

Discovering oxidative potential (OP) drivers of atmospheric PM10, PM2.5, and PM1 simultaneously in North-Eastern Spain

Ambient particulate matter (PM) is a major contributor to air pollution, leading to adverse health effects on the human population. It has been suggested that the oxidative potential (OP, as a tracer of oxidative stress) of PM is a possible determinant of its health impact. In this study, samples of PM₁₀, PM_2.5, and PM₁ were collected roughly every four days from January 2018 until March 2019 at a Barcelona urban background site and Montseny rural background site in northeastern Spain. We determined the chemical composition of samples, allowing us to perform source apportionment using positive matrix factorization. The OP of PM was determined by measuring reactive oxygen species using dithiothreitol and ascorbic acid assays. Finally, to link the sources with the measured OP, both a Pearson's correlation and a multiple linear regression model were applied to the dataset. The results showed that in Barcelona, the OP of PM₁₀ was much higher than those of PM_2.5 and PM₁, whereas in Montseny results for all PM sizes were in the same range, but significantly lower than in Barcelona. In Barcelona, several anthropogenic sources were the main drivers of OP in PM₁₀ (Combustion + Road Dust + Heavy Oil + OC-rich) and PM_2.5 (Road Dust + Combustion). In contrast, PM₁ -associated OP was driven by Industry, with a much lower contribution to PM₁₀ and PM_2.5 mass. Meanwhile, Montseny exhibited no clear drivers for OP evolution, likely explaining the lack of a significant difference in OP between PM₁₀, PM_2.5, and PM₁. Overall, this study indicates that size fraction matters for OP, as a function of the environment typology. In an urban context, OP is driven by the PM₁₀ and PM₁ size fractions, whereas only the PM₁ fraction is involved in rural environments.

The characteristics of polycyclic aromatic hydrocarbons and heavy metals in water and sediment of dajiuhu subalpine wetland, shennongjia, central China, 2018-2020: Insights for sources, sediment-water exchange, and ecological risk

Polycyclic aromatic hydrocarbons (PAHs) and heavy metals (HMs) are persistent environmental issues. Secondary emissions are produced as a result of climate change and human activity. To observe spatio-temporal variations of PAHs and HMs and to discuss the sources as well as the source or sink of PAHs for sediment and peat, twelve surface sediment and surface water sites were chosen along the direction of the flow to down hole in the Dajiuhu area, simultaneously, surface peat and water samples were collected in peatland. Samples were continuously taken for three years (Sep. 2018, Sep. 2019, and Sep. 2020, respectively). The results showed that PAHs and HMs are common in sediment and peat. PAHs concentration is generally higher in peat and water, while HMs concentration is relatively higher in water and relatively low in sediment and peat, and the ecological risk of sediment was low. HMs in sediment are mainly affected by rock weathering, while PAHs are mainly affected by atmospheric deposition, biomass and coal combustion and vehicle emission. HMs and PAHs can be used as an indicator of rock weathering and human activity in Dajiuhu area, respectively. A water-sediment fugacity analysis revealed that peat is a sink for PAHs, confirming that it has a high capacity for adsorbing organic contaminants, and that sediments are secondary sources of PAHs that can release them into water. Attention should be paid to the increased fugacity fraction (ff) value in peatland, indicating that peat might be converted from a sink to a source of PAHs.

Source apportionment, identification and characterization, and emission inventory of ambient particulate matter in 22 Eastern Mediterranean Region countries: A systematic review and recommendations for good practice

Little is known about the main sources of ambient particulate matter (PM) in the 22 Eastern Mediterranean Region (EMR) countries. We designed this study to systematically review all published and unpublished source apportionment (SA), identification and characterization studies as well as emission inventories in the EMR. Of 440 articles identified, 82 (11 emission inventory ones) met our inclusion criteria for final analyses. Of 22 EMR countries, Iran with 30 articles had the highest number of studies on source specific PM followed by Pakistan (n = 15 articles) and Saudi Arabia (n = 8 papers). By contrast, there were no studies in Afghanistan, Bahrain, Djibouti, Libya, Somalia, Sudan, Syria, Tunisia, United Arab Emirates and Yemen. Approximately 72% of studies (51) were published within a span of 2015-2021.48 studies identified the sources of PM_2.5 and its constituents. Positive matrix factorization (PMF), principal component analysis (PCA) and chemical mass balance (CMB) were the most common approaches to identify the source contributions of ambient PM. Both secondary aerosols and dust, with 12-51% and 8-80% (33% and 30% for all EMR countries, on average) had the greatest contributions in ambient PM_2.5. The remaining sources for ambient PM_2.5, including mixed sources (traffic, industry and residential (TIR)), traffic, industries, biomass burning, and sea salt were in the range of approximately 4-69%, 4-49%, 1-53%, 7-25% and 3-29%, respectively. For PM₁₀, the most dominant source was dust with 7-95% (49% for all EMR countries, on average). The limited number of SA studies in the EMR countries (one study per approximately 9.6 million people) in comparison to Europe and North America (1 study per 4.3 and 2.1 million people respectively) can be augmented by future studies that will provide a better understanding of emission sources in the urban environment.

Monitoring, Source Identification and Environmental Risk of Potentially Toxic Elements of Dust in Isfahan Province, Central Iran

The aim of this study was to identify potentially toxic elements (PTEs) associated with airborne particulate matters (PMs) and their source identification and environmental risk in Isfahan Province, central Iran. Dust samples were collected from various locations included three urban and four rural locations. Results revealed the eastern part of the region as the main source of dust and showed that the highest monthly atmospheric dust deposition was in July (5.53 g m^-2). The mean concentrations of Zn, Pb, Cu and Cd were respectively 279, 63, 49 and 0.5 mg kg^-1 in dust samples, whereas Cd showed the highest ecological risk index. Dust samples of urban areas showed considerable and very high levels of pollution indices for Pb and Zn, respectively. Among the metals, Zn showed the highest enrichment factor (>5), mainly due to anthropogenic sources. The comprehensive ecological risk index of PTEs revealed the moderate and considerable risk of Isfahan and Najafabad cities, respectively.

Heavy metal pollution levels, source apportionment and risk assessment in dust storms in key cities in Northwest China

In this study, the potential hazards of heavy metals in dust storms were investigated by collecting dust storm samples, measuring their heavy metal concentrations, and using index evaluation, spatial analysis, positive matrix factorization (PMF) model and risk assessment model. Heavy metals in dust storms were contaminated by anthropogenic sources leading to their concentrations being higher than the background values. The enrichment factors and geoaccumulation indices showed that the heavy metals came from both natural and anthropogenic sources, Cu, Ni, Zn and Pb are strongly influenced by anthropogenic sources. Heavy metals in dust storms were divided into four sources: Cu and Ni were attributed to industrial sources mainly from local mining and metal processing; Cr was mainly contributed by industrial sources related to industrial production such as coal combustion; Pb and Zn were mainly contributed by transportation sources; and Ti, V, Mn, Fe, and As were from natural and agricultural sources. The level of comprehensive ecological risk of heavy metals in dust storms were low, but there were moderate and above risks at individual sites. Both adults and children had the highest carcinogenic and non-carcinogenic risks from the ingestion route, and the risk for children was higher than that for adults.

Correlation between heavy metal concentration and oxidative potential of street dust

The current study aimed to consider oxidative potential (OP), its spatial distribution, and correlations with heavy metals (HMs) in street dust in Kerman city, Iran. The concentration of HMs in 35 street dust samples was detected by ICP-AES. The OP in samples was measured through dithiothreitol (DTT). The mean concentration of elements followed Zn > Cu > Pb > Cr > As > Cd. The OP value was found to be 7.17 ± 2.98 nmol/min. µg dust in the current study. A strong correlation was observed among the concentrations of As and Cr and OP values in dust samples. More values of OP were observed in the center and west of the Kerman city. According to results of the current study, it could be concluded that OP can be applied as metrics of pollution originated from different sources and human health effects. The amount of OP in the street dust in the Kerman city can be reduced through the use of clean fuels.

Advanced mineral magnetic and geochemical investigations of road dusts for assessment of pollution in urban areas near the largest copper smelter in SE Europe

This study aims to evaluate the urban pollution by combined magnetometric and geochemical analyses on road dusts from three towns in the vicinity of Cu-smelter and ore mining. A collection of 117 road dust samples was investigated for their magnetic characteristics (magnetic susceptibility (χ), frequency dependent susceptibility, anhysteretic and isothermal (IRM) remanences), IRM step-wise acquisition and thermal demagnetization. Coarse grained magnetite and hematite were identified as major iron oxides in the emissions from ore spills and smelter, while traffic-related magnetic minerals were finer magnetite grains. Degree of pollution is assessed by geo-accumulation index, enrichment factor and Pollution Load Index (PLI) for a set of potentially toxic elements (PTEs). Using the geochemical data, we evaluate the carcinogenic and non-carcinogenic health risks for the population. Our results show that dust emissions from the industrial facilities likely pose significant health hazard for adults and children caused largely by Arsenic pollution in "hot spots". Based on the strong correlation between χ and most of the PTEs, detailed variations in pollution degree inside the urban areas are inferred. Strong linear regression between χ and PLI allows designating limit susceptibility values, corresponding to the PLI categories. This approach can be successfully applied for monitoring and mapping purposes at high spatial and temporal resolution.

Investigation of the 2018 Shiraz dust event: Potential sources of metals, rare earth elements, and radionuclides; health assessment

In the middle of May 2018, an unprecedented dust storm occurred in the Shiraz metropolis. After the storm, several samples were collected from dust that settled around the city. These dust samples were analysed for potentially toxic elements (PTEs), rare earth elements (REEs), and radionuclides. This work is the first study that considered rare earth elements (REEs) for source identification and radionuclide contamination of Shiraz dust event. Hysplit model analysis and NASA and NOAA satellite maps illustrated that the air mass affecting Shiraz was moving mainly through the Saudi Arabian deserts. In addition, REE results of the dust that settled in Shiraz showed a trend similar to shale, sandstone, and especially Saudi Arabian soils. Ti/Al (0.01), Fe/Al (0.92), and Mg/Al (0.55) ratios and the values of LaN/SmN (0.91-0.98), GdN/YbN (1.8-2), LaN/YbN (1.7-1.9), HREE/LREE (0.52-0.6), Ce/Ce∗ (1.09-1.13), Eu/Eu∗ (1.03-1.18), Pr/Pr∗ (0.85-0.87), Gd/Gd∗ (1.1-1.15), and MREEs/MREE∗ (4.3-4.5) ratios provided insights into dust sources. These values indicated that Shiraz dust was affected by Asaluyeh and Iraq soils during transport and the main source of the dust that settled in Shiraz on the May 13, 2018 was Saudi Arabian soil. The concentrations of Mo, Cu, Pb, Zn, Ni, Co, Mn, As, Cd, Ti, Al, Sc, and Fe in the settled dust were 0.24, 47.67, 67.33, 244, 70.27, 19.33, 664, 8.39, 0.65, 537.33, 40933.33, 11.54, and 37800 mg/kg, respectively. According to the enrichment factor (EF), coefficient variation, and Positive Matrix Factorization (PMF) model the Mo, Cu, Pb, Zn, and Cd mainly originated from exhaust emissions and industrial activities. The activity concentrations of the radionuclides ⁷Be, ⁴ K, ¹³⁷Cs, and ²³⁵U in the Shiraz-settled dust were 814, 421, 14, and 5.4 Bq kg^-1, respectively and the activity concentration of ⁴ K was higher than the crustal average. Health risk assessment indices for the elements considering all three pathways revealed the following trend: dermal contact (HQ_derm)< inhalation (HQ_inh)< ingestion (HQ_ing). The values of HQ_inh and HQ_ing for children were higher than adults, while the values for the skin adsorption pathway for adults were higher than for children.

Magnetic monitoring of topsoil and street dust in Xinyang (China) and their environmental implications

The magnetic measurement is an effective tool to identify the source of pollutants and diagnose the urban pollution. In this study, 132 group samples (that topsoil and street dust were sampled at the same location is regarded as a group) were collected from Xinyang, central eastern China. In addition, the background samples (19 topsoils under woodland around the outskirts) were also sampled. Herein, the aim was to investigate and compare the magnetic characteristics of both topsoil and street dust, and further to discuss the source and environmental implications using magnetic and diffuse reflection spectrum methods. The following points are highlighted: (1) the primary magnetic carrier of both materials was magnetite and that of the background sample were magnetite and maghemite. Furthermore, the ferrimagnetic mineral concentration and magnetic domain follow the order: street dust > topsoil > background sample. (2) The source of both materials was mainly from anthropogenic activities (e.g. industrial and traffic vehicles). The difference between them was the contribution related to natural sources (e.g. parent materials), which was negligible in street dust, and played a secondary role in topsoil. (3) Both materials showed that areas with a higher intensity of anthropogenic activities had higher pollution level, whereas areas with a lower anthropogenic intensity had lower pollution level.

Physico-chemical properties and reactive oxygen species generation by respirable coal dust: Implication for human health risk assessment

This study investigates the mineralogy, micro-morphology, chemical characteristics and oxidation toxicity of respirable dusts generated in underground coal mines. The active sampling was applied to collect airborne particulates with aerodynamic diameter <4 µm (PM₄) at depth greater than 500 m from earth surface. The average mass concentration of PM₄ was extremely higher than recommended values. QXRD and FESEM-EDS analyses were applied to study the micro-mineralogy and micro-morphology of respirable dusts. The chemical analysis by ICP-MS revealed an enrichment of V, Cr, Cu, Zn, As, Ag, Cd and Sb in respirable dust compared with the background environment and world coals. The EPA's health risk model showed that the health risk posed by Cr and Co in all workplaces exceeded the acceptable risk value for human health. The synthetic respiratory tract lining fluid (RTLF) model was utilized to achieve a novel insight into the toxicity of respirable coal dust. The result showed an overall depletion of lung surface antioxidants with the decreasing trend of ascorbic acid > reduced glutathione >> urate, implying low- to medium level of oxidative stress. The result of this study can be applied globally by decision-makers to decrease hazardous exposure of mine workers to respirable dust.

Thoracic Fraction (PM10) of Resuspended Urban Dust: Geochemistry, Particle Size Distribution and Lung Bioaccessibility

A fluidized bed aerosol generator was connected to a 13-stage cascade impactor (nanoMOUDI) for the size fractionation of urban dust (<10 µm), followed by the gravimetric analysis of loaded PTFE filter samples. This method was used to characterize the PM10 (thoracic) fraction of road dust sampled from expressways, arterial roads and local roads in Toronto, Canada. The fine particle fractions (<1.8 µm) of all the studied samples accounted for 51–72% of the resuspended PM10 (by weight). Elemental analysis using ICP-MS and ICP-OES revealed an overall trend of element enrichment in the <1.8 µm fraction compared to the coarse fraction (1.8–10 µm) of the road dust. By contrast, archived house dust samples displayed the reverse trend for most elements. The lung bioaccessibility of target elements (Al, B, Ba, Co, Cr, Fe, La, Mn, Mo, Sb, Sr, Ti, V and Zn) was assessed for each road dust fraction using 0.1 M ammonium citrate (pH 4.4) to simulate intracellular fluid and Gamble solution (pH 7.2) to simulate interstitial lung fluid. The <1.8 µm fraction of local road dust displayed significantly higher bioaccessibility (p < 0.05) for Zn when using Gamble solution, and for seven out of the 14 target elements when using ammonium citrate. These results show the importance of characterizing the fine fraction of road dust.

Spatial and Temporal Distribution of Pollution Based on Magnetic Analysis of Soil and Atmospheric Dustfall in Baiyin City, Northwestern China

The characteristics of spatial-temporal distribution and sources for multiple environmental carriers (surface soil, soil profiles, atmospheric dustfall) from the typical industrial city of Baiyin in Northwestern China were studied by means of environmental magnetism. This study aims to contribute to the potential application of magnetic measurements in the case of multiple environmental carriers, for the evaluation and differentiation of urban pollution sources. Results show that background magnetic susceptibility of soil is 37 × 10⁻⁸ m³ kg⁻¹, and that magnetite and hematite carry the magnetic properties. However, magnetic properties of urban soil and atmospheric dustfall are dominated by PSD magnetite. Magnetite content in soil samples is anomalously high surrounding metallurgical plant and slag dump (major industry district), of moderate value in the center of the city (major commercial district), and of low value in the west of city (Baiyin new zone). Vertical distribution of magnetite content in soil profile of waste land suggests that the pollutants are mostly enriched in the top 0–2 cm soil layers, while planting of crops near the industrial area may accelerate the transfer of contaminants deeper in the soil (2–30 cm); accordingly, reducing detrimental soil tillage practices can alleviate the vertical migration of pollution. Measurements of magnetic variations of atmospheric dustfall indicate that industrial emissions by factory chimneys and blowing dust from slag heap and mineral transport control the magnetic properties of dust, with slag heaps being the main pollution source since 2014. Governance of slag pollution is a primary task in resource-exhausted urban contexts. The combination of several magnetic parameters arising from multiple environmental carriers, such as soil and atmospheric dustfall, can provide comprehensive spatio-temporal information on environmental pollution.

Potentially toxic elements in the Middle East oldest oil refinery zone soils: source apportionment, speciation, bioaccessibility and human health risk assessment

In this research, fifteen potentially toxic elements (PTEs) (Al, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Sb, Sc and Zn) were analysed and quantified in samples collected at 44 sites in an urban area of Iran. Sources were apportioned using enrichment factors (EFs), modified pollution index (MPI), principal component analysis (PCA), multivariate linear regression of absolute principal component scores (MLR-APCS) and speciation, with a focus on anthropogenic PTEs in the urban and industrial soils of the Arvand Free Zone area, an oil-rich zone in the country. Furthermore, the bioaccessibility and the human health risks of PTEs were investigated. The EF revealed a significant enrichment for elements such as Cd, Cu, Hg, Mo, Pb, Sb and Zn. Values of MPI showed that Abadan industrial district and Abadan petrochemical complex are the most polluted sites in the study area.The PCA/MLR analysis revealed four main sources: natural sources, fossil fuel combustion, traffic and oil derivatives and petroleum waste. The relative contribution of each source to PTE concentration varied from 32.3% of the natural sources to 30.6% of traffic and from 20.1% of petroleum waste to 17% of fossil fuel combustion. The source apportionment of metals generated using MLR-APCS receptor modelling revealed that 85.0% of Hg was generated by oil products. Chemical speciation results were compatible with the results obtained from PCA. Bioaccessibility of PTEs decreased from gastric to intestinal phase except Mo and Sb due to their different geochemical characteristics. Hazard index (HI) for non-cancer risk of PTEs for both children and adults based on total element concentrations was estimated to range from 2-fold to more than 10-fold higher than that of bioaccessible phases.

Identifying environmental pollution recorded in street dust using the magnetic method: a case study from central eastern China

Urban street dust constitutes important intermediate products for the transmission of solid organic and inorganic pollutants in the urban environment. In this study, 133 street dust samples were collected from Xinyang to explore their magnetic characteristics, spatial distribution, and environmental implications using magnetic measurements. The results are as follows. (1) There were ferrimagnetic, antiferrimagnetic, and paramagnetic (e.g., lepidocrocite) minerals in the dust. Among these, the dominant magnetic carriers were ferrimagnetic minerals. Furthermore, magnetite was a first-order ferrimagnetic carrier. (2) The magnetic domains of the dust were pseudo single-domain to multi-domain. (3) The magnetic concentration (χ and SIRM) of dust were 2.6 and 4.1 times higher than those of background samples that were not polluted by urban and anthropogenic activities, respectively. Therefore, we conclude that the dust consisted of high concentration of ferrimagnetic minerals and coarse magnetic particles. (4) The magnetic distribution was spatially different. The industrial area, which was the most polluted sampling area, had the highest magnetic concentration and the coarsest magnetic particles. This was attributable to industrial emissions, fossil fuel combustion, and exhaust emissions from heavy-laden trucks. Residential and commercial areas, which were the second most polluted areas, had higher concentration and coarser particles. This was primarily due to the high population density and traffic activities of mini-cars (i.e., high flux and exhaust emissions). Hence, the conclusion is that the magnetic characteristics, spatial distribution, and the sources of dust are dictated by anthropogenic activities. Our results indicate that the magnetic method is a highly effective tool to monitor urban environmental pollution.