Pollution and health risk of potentially toxic metals in urban road dust in Nanjing, a mega-city of China

The relationship between the inhalation bioaccessibility of potentially toxic elements in road dust from a heavily polluted industrial area and the source of their pollution

One of the sources of chronic exposure to potentially toxic elements (PTE), especially in polluted environments, is the inhalation of resuspended road dust (RD). The aim of this study is to assess the inhalation bioaccessibility of PTE in RD from highly polluted environments from mining/smelting industries and traffic, and to identify any correlations between the bioaccessibility fraction of PTE and the physicochemical characteristics of the particles. RD from the studied area contains extremely high total concentrations of Cr, V, and Mn, which are likely due to pollution from the smelting industry. Additionally, elevated total concentrations of other elements associated with traffic emissions including Zn, Cu, Pb, Sb, and Sn were also measured. The bioaccessibility of PTE was assessed using two synthetic extraction solutions - Gamble's solution (GS) and Artificial Lysosomal Fluid (ALF). The majority of elements showed negligible bioaccessibility in GS. However, quite high inhalation bioaccessibility was observed for Zn, Pb, Sb, Cd, and Mn in the ALF solution, with a mean bioaccessible fraction of 49, 51.5, 41, 50, and 40% respectively. The highest bioavailable fraction was measured for Cd (97%) in a sample collected near a steel production facility and for Pb (95%) in a sample collected near the highway. These results indicate that increased mobility of the elements in inhaled particles occurs only in the case of phagocytosis. The lowest inhalation bioavailability was measured for Cr (mean is 3%). Differential individual particle analysis revealed that about 60% of phases, mostly major (Cr,Ti,V)-bearing metallic alloys, silicates, oxides and sulphides, are stable in ALF solution, while 40% of phases, mostly (Fe,Ca,Mn)-bearing oxides, silicates, sulphides, metals and metallic alloys originating from steel production, ferrochrome, ferrosilicon and vanadium production and from traffic emissions have been heavily corroded or completely dissolved. The study provides valuable information to further assess health hazards from various emission sources.

Red Cell Distribution Width and Mean Corpuscular Volume Alterations: Detecting Inflammation Early in Occupational Cement Dust Exposure

Introduction Cement dust emitted during cement manufacture consists of toxic components. Occupational cement dust exposure may cause inflammation in the human body, which may be detected early by observing changes in blood parameters such as red blood cell distribution width (RDW) and mean corpuscular volume (MCV). Objectives The study aims to observe the effect of occupational cement dust exposure on RDW and MCV. Methods This study was performed in the Department of Physiology of Dhaka Medical College, Dhaka, Bangladesh, and a factory in Munshiganj, Bangladesh, from September 2017 to August 2018. Ninety-two participants between 20 and 50 years were included (46 subjects were occupationally exposed to cement dust, and 46 were not exposed to cement dust). A pre-designed questionnaire was used for data collection. An independent sample t-test was used to analyze basic information, such as blood pressure and BMI. The multivariate regression model was used to analyze the effect of cement dust exposure on the study group. The impact of cement dust exposure duration was analyzed using the multivariate regression model. The level of significance was p < 0.05. The statistical analysis was performed using STATA-15 (StataCorp, College Station, TX), and the graphical presentation used GraphPad Prism v8.3.2. Results The cement dust-exposed participants had a significantly higher value of MCV by 1.19 fi (95% CI = 0.02, 4.84; p = 0.049) and a 5.92% increase in RDW (95% CI = 5.29, 6.55; p < 0.001) than that of the control group. Conclusion The study reveals that exposure to cement dust causes significant changes in RDW and MCV. These changes may indicate hemolysis due to inflammation.

Assessing heavy metal contamination in a Brazilian metropolis: a case study with a focus on (bio)indicators

The continuous expansion of the global vehicle fleet poses a growing threat to environmental quality through heavy metal contamination. In this scenario, monitoring to safeguard public health in urban areas is necessary. Our study involved the collection of 36 street dust and 29 moss samples from roads of a Brazilian metropolis (Recife) with varying traffic intensities as follows: natural reserve (0 vehicles per day), low (< 15,000 vehicles per day), medium (15,000-30,000 vehicles per day), and high (> 30,000 vehicles per day). ICP-AES analysis was performed to determine the concentrations of nine potentially toxic metals (Ba, Cd, Cr, Cu, Mn, Ni, Pb, V, and Zn) to assess the influence of vehicular flow on urban contamination. In the street dust samples, the mean metal concentrations (mg kg-1) exhibited the following order: Ba (503.7) > Mn (303.0) > Zn (144.4) > Cu (95.3) > Cr (56.1) > Pb (34.2) > V (28.7) > Ni (11.3) > Cd (1.5). Conversely, in the moss samples, the metal concentration order was as follows (mg kg-1): Mn (63.8) > Zn (62.5) > Ba (61.0) > Cu (17.7) > Cr (8.0) > V (7.3) > Pb (7.0) > Ni (2.9) > Cd (0.3). Roads with higher traffic volumes exhibited the highest metal enrichments in moss samples for all metals and in dust samples for Cd, Cr, Mn, Ni, and V. However, dust from low-flow roads had higher enrichments for Ba, Cu, and Zn, indicating the influential role of other traffic-related factors in metal deposition. Our findings highlight traffic flow as the predominant source of pollution in urban centers, with both street dust and moss serving as sensitive indicators of metal input attributable to vehicular traffic. These indicators offer valuable insights for urban quality monitoring and pollution control efforts.

Assessment of elemental chemistry, spatial distribution, and potential risks of road-deposited dusts in Sharjah, United Arab Emirates

Road dust is a major source of pollution in the environment, carrying different pollutants, including heavy metals and metalloids, from one location to another. This study assesses the concentrations of eight heavy metals and one metalloid (Zn, Pb, Mn, Fe, Cr, Cu, Cd, Ni, and As) in dust samples collected from sixty-eight streets of Sharjah, United Arab Emirates using ICP-OES, as well as investigates their effects on both the environment and humans. Mean concentrations of the elements in μg/g across the sites were 392 ± 46 (Zn), 68.28 ± 11.3 (Pb), 1437 ± 67 (Mn), 39,481 ± 4611 (Fe), 460 ± 31 (Cr), 150 ± 44 (Cu), 1.25 ± 0.65 (Cd), 856 ± 72 (Ni), and 0.97 ± 0.28 (As). The Cdeg and ERI calculated from the study were 54.79 and 573, respectively, suggesting varying pollution levels. The highest contributions were from Ni, Cd, Zn, Cu, Cr, and Pb, especially in areas with heavy traffic. The non-carcinogenic risk assessments were generally low for the three routes of exposure, except HQoral that was slightly higher for children. Similarly, none of the elements exhibited any carcinogenic risk except chromium. Overall, the cancer risk is considered low. In view of the limited studies from UAE in relation to the metal content of road-deposited dusts, the current study serves as novel knowledge, especially in the context of geographical areas with a higher occurrence of sandstorms and the presence of particulate matter. The study also adds to the global understanding of the contribution of street dust to environmental pollution and its implications for human health.

Pollution indices of selected metals in tea (Camellia sinensis L.) growing soils of the Upper Assam region divulge a non-trifling menace of National Highway

The study investigated the influence of a National Highway (NH) traversing tea estates (TEs) on heavy metal (HM) contamination in the top soils of Upper Assam, India. The dispersion and accumulation of six HMs, viz. cadmium (Cd), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), and zinc (Zn), within tea-growing soils were assessed using diverse indices: contamination factor (CF), degree of contamination (DC), enrichment factor (EF), geo-accumulation index (Igeo), modified degree of contamination (MDC), Nemerow pollution index (PINemerow), pollution load index (PLI), potential ecological risk factor (Eri), and potential ecological risk index (RI). The order of HM prevalence was Fe > Mn > Zn > Ni > Cu > Cd. Elevated Cd levels near the NH prompted immediate attention, while Cd and Zn showed moderate pollution in CF, EF, and RI. The remaining metals posed minimal individual risk (Eri< 40), resulting in an overall contamination range of "nil to shallow," signifying slight contamination from the studied metals. From MDC values for investigated metals, it was found to be "zero to very low degree of contamination" at all locations except the vicinity of NH. Soil pollution, as determined by PLI, indicated unpolluted soils in both districts, yet PINemerow values indicated slight pollution. The statistical analysis revealed that there is a significant decrease in most of the indices of HM as the distance from NH increases. The application of multivariate statistical techniques namely Principal Component Analysis and Cluster Analysis showed the presence of three distinct homogenous groups of distances based on different indices. This investigation underscores NH-associated anthropogenic effects on TE soil quality due to HM deposition, warranting proactive mitigation measures.

Human health risk assessment of metal-contaminated soils in Sydney estuary catchment (Australia)

Sydney estuary catchment supports the largest city in Australia and provides essential eco-social and environmental services; however, the region has been influenced by extensive anthropogenic modification. Soil metal concentrations in the catchment had been studied previously; however, the current investigation was designed to determine the risk posed by these contaminants to human health. Soil metal concentrations were higher than observed in most global capitals and increased substantially in the south and south-east of the catchment and close to the central business district. Road-side soils and road dust contained the highest concentration of metals in the catchment. Lead in catchment soils was closely related to traffic density and sourced from the historic use of Pb in petrol. A human health assessment indicated that soil Cd, Ni and Zn posed no non-carcinogenic risk (NCR), or carcinogenic risk (CR) for children, or adults in Sydney estuary catchment and that Cu and Cr may pose minor NCR for children. Vehicle-related Pb raised the greatest human health risk in catchment soils and may pose NCR at 32% and 4.3% of sites for children and adults, respectively. Inconsistent analytical techniques used in CR and NCR evaluations produce incomparable assessments and a consistent` methodology is suggested to improve interpretation. Human health risk may well be higher than commonly calculated due to pollutants present in urban soil not being included in assessments.

Review and assessment of road-derived metals as a major contributor of metallic contaminants to urban stormwater and the estuarine environment (Sydney estuary, Australia)

Sydney Harbour (Australia). is one of the most metal-contaminated in the world and sediments are toxic over large areas. The major source of metals is stormwater, however there remains considerable debate regarding the source of metals in water entering the estuary. The current review and critical assessment of a large source of data accumulated from over three decades of research, supplemented by global studies, identified road-derived metals (RDMs) as the chief contributor of metals to stormwater and consequently to pollution of the estuary. Roads comprise almost 25% of a typical urban catchment and generate a considerable metal load from highly effective impervious surfaces and RDM is transported directly to the adjacent receiving basin with enhanced connectivity. In Sydney, industrial waste is delivered to the sewage system and is disposed of offshore, leaving RDM as a major contributor of metals to the stormwater system and estuarine environment. RDMs are modelled to be hazardous to the ecology and human health (carcinogenic and non-carcinogenic diseases) in the catchment environment driven by high metal concentrations, small size and elevated bioavailability. Remediation of RDMs is complex, requiring extensive knowledge and an experienced management team. The enormous potential for water re-use is often neglected.

Road dust exposure and human corneal damage in a plateau high geological background provincial capital city: Spatial distribution, sources, bioaccessibility, and cytotoxicity of dust heavy metals

Ocular surface diseases are common in the plateau city, Kunming China, the continued daily exposure to heavy metals in dust may be an important inducement. In this study, the 150 road dust samples from five functional areas in Kunming were collected. The concentrations, distribution, possible sources, and bioaccessibility of heavy metals were analyzed. The adverse effects of dust extracts on human corneal epithelial cells and the underlying mechanisms were also assessed. The concentrations (mg·kg-1) of As (19.1), Cd (2.67), Cr (90.5), Cu (123), Pb (78.4), and Zn (389) in road dust were higher than the soil background, with commercial and residential areas showing the highest pollution. Their bioaccessibility in artificial tears was As (6.59 %) > Cu (5.11 %) > Ni (1.47 %) > Cr (1.17 %) > Mn (0.84 %) > Cd (0.76 %) > Zn (0.50 %) > Pb (0.31 %). The two main sources of heavy metals included tire and mechanical abrasion (24.5 %) and traffic exhaust (21.6 %). All dust extracts induced cytotoxicity, evidenced by stronger inhibition of cell viability, higher production of ROS, and altered mRNA expression of antioxidant enzymes and cell cycle-related genes, with commercial- areas-2 (CA2)-dust extract showing the greatest oxidative damage and cell cycle arrest. Our data may provide new evidence that dust exposure in high geological background cities could trigger human cornea damage.

Investigating seasonal air quality variations consequent to the urban vegetation in the metropolis of Faisalabad, Pakistan

Urban atmospheric pollution is global problem and and have become increasingly critical in big cities around the world. Issue of toxic emissions has gained significant attention in the scientific community as the release of pollutants into the atmosphere rising continuously. Although, the Pakistani government has started the Pakistan Clean Air Program to control ambient air quality however, the desired air quality levels are yet to be reached. Since the process of mapping the dispersion of atmospheric pollutants in urban areas is intricate due to its dependence on multiple factors, such as urban vegetation and weather conditions. Therefore, present research focuses on two essential items: (1) the relationship between urban vegetation and atmospheric variables (temperature, relative humidity (RH), sound intensity (SI), CO, CO2, and particulate matter (PM0.5, PM1.0, and PM2.5) and (2) the effect of seasonal change on concentration and magnitude of atmospheric variables. A geographic Information System (GIS) was utilized to map urban atmospheric variables dispersion in the residential areas of Faisalabad, Pakistan. Pearson correlation and principal component analyses were performed to establish the relationship between urban atmospheric pollutants, urban vegetation, and seasonal variation. The results showed a positive correlation between urban vegetation, metrological factors, and most of the atmospheric pollutants. Furthermore, PM concentration showed a significant correlation with temperature and urban vegetation cover. GIS distribution maps for PM0.5, PM1.0, PM2.5, and CO2 pollutants showed the highest concentration of pollutants in poorly to the moderated vegetated areas. Therefore, it can be concluded that urban vegetation requires a rigorous design, planning, and cost-benefit analysis to maximize its positive environmental effects.

Health Risk Assessment of Heavy Metals in Indoor Household Dust in Urban and Rural Areas of Chiang Mai and Lamphun Provinces, Thailand

Indoor exposure to heavy metals poses human health risks worldwide, but study reports from Thailand are still limited, particularly in rural and urban areas. We measured the heavy metals in a hundred indoor household dust samples collected from urban and rural areas in Chiang Mai and Lamphun provinces and found a significantly higher concentration of As in rural areas and Cd in urban areas with industrial activities. The source identification of the heavy metals showed significant enrichment from traffic emissions, paint, smoking, and mixed sources with natural soil. From health risk assessment models, children were more vulnerable to noncarcinogenic risks (HI = 1.45), primarily via ingestion (HQ = 1.39). Lifetime cancer risks (LCRs) due to heavy metal exposure were found in adults (LCR = 5.31 × 10-4) and children (LCR = 9.05 × 10-4). The cancer risks from As were higher in rural areas via ingestion, while Cr and Ni were higher in urban areas via inhalation and ingestion, respectively. This study estimated that approximately 5 out of 10,000 adults and 9 out of 10,000 children among the population may develop cancer in their lifetime from exposure to indoor heavy metals in this region.

Similarity in human health risk assessment using models of soil-blood lead levels (IEUBK) and non-carcinogenic condition (US EPA 2002)

Soil lead (Pb) concentrations in Sydney estuary (Australia) catchment are substantially elevated and strongly associated with traffic networks. This study compared the health risk predictions of blood Pb levels (BLL) in children using the soil IEUBK model and an independent, non-carcinogenic human health risk (NCR) assessment using the soil US EPA 2002 model. The predictions by the two models were significantly correlated (p < 0.001) and showed similar spatial distributions, but the NCR model may be more stringent in protection of human health when exposed to soil Pb in relation to adverse health effect, as the warning soil Pb concentration from the BLL was 4.6-fold higher than that from the NCR. The empirical IEUBK model considers gastric phase adsorption only and of the three exposure pathways (ingestion, inhalation and dermal) assessed by the theoretical NCR model, ingestion was the major exposure route. The reason for the similarity in outcomes of the two models is unknown, however the close correlation may be due to broadly similar formulations and, or that neurological and non-carcinogenic risks may be related to the adverse effects of Pb on bodily function. Parallel studies of human health risk based on BLL and NCR models have not been attempted previously and this opportunity to compare results from the two health risk assessments employing the same soil metal data is therefore unique.

Assessment of potentially toxic elements in atmospheric dust and associated health risks in Zahedan City, Iran

Zahedan City is situated in the Sistan basin, a highly active dust source region that poses significant risks to human and ecological health due to potentially toxic elements (PTEs) present in atmospheric dust. In this study, we investigated the concentration, sources, and human health risk assessment of PTEs in 88 monthly atmospheric dust samples collected between December 2020 and October 2021 using inductively coupled plasma mass spectrometry. The results showed that the concentrations of PTEs in atmospheric dust followed the descending order of Mn > Zn > Ba > Sr > Cr > V > Ni > Cu > Pb > Co > As > Mo > Cd. The calculated enrichment factors revealed significant enrichment for As > Zn, moderate enrichment Pb > Ni, deficiency to minimal enrichment for Cr > Mn > Fe > Sr > Cd > V > Cu > Ba > Co, and no enrichment for Mo. Arsenic was found to be the major contributor to the potential ecological risk index, accounting for 55% of the total risk. The widespread utilization of arsenic-based pesticides in the surrounding agricultural lands may be a significant contributor to the severe arsenic pollution in the region. The winter season exhibited the highest monthly mean concentrations of Zn and Pb possibly due to temperature inversions trapping local anthropogenic pollutants near the Earth's surface. Cluster analysis revealed a strong correlation between Ni-Cr-Fe-V-Mn-Al, which shows mainly the geogenic source for these elements. The predominant exposure route for non-carcinogenic risk to humans was ingestion. The hazard index (HI) values for the heavy metals studied decreased in the following order: Cr > As > Pb > Ni > Zn > Cu > Cd, for both children and adults. The HI values indicated that there was no possible non-carcinogenic risk associated with exposure to these heavy metals in Zahedan's atmospheric dust. The result of the inhalation cancer risk assessment suggested that while the potential risks of cancer for As, Cd, Cr, and Ni were below the safe level, the levels of Chromium were close enough to the threshold to warrant further investigation and monitoring.

Source identification and health risk assessment of heavy metals with mineralogy: the case of soils from a Chinese industrial and mining city

Understanding the precise sources of heavy metals (HMs) in soil and the contribution of these sources to health risks has positive effects in terms of risk management. This study focused on the HMs in the soil of five land uses in an industrial and mining city. The sources of HMs in soils were identified, and the soil mineralogical characteristics and health risks of HMs were discussed. The results showed that the HMs (Cu, Zn, Ni, Cd, Pb) found in the soil of the five land uses were affected by human activities. For example, the Cu in grassland, gobi beach, woodland, green belt, and farmland is 22.3, 3.5, 22.5, 16.7, and 21.3 times higher than the soil background values in Gansu Province, respectively. The Positive Matrix Factorization model (PMF) results revealed that traffic emissions and industrial and agricultural activities were the primary sources of HMs in the soil, with industrial sources accounting for the largest share at 55.79%. Furthermore, various characteristics proved that the studied HMs were closely related to smelting products. Concentration-oriented health risk assessments showed that HMs in the different soil types held non-carcinogenic and carcinogenic risks for children and adults. Contamination source-oriented health risk assessments of children and adults found that industrial activities controlled non-carcinogenic and carcinogenic risks. This study highlighted the critical effects of smelting on urban soil and the contribution of pollution sources to health risks. Furthermore, this work is significant in respect of the risk control of HMs in urban soils.

Integrative assessment of urban dust polycyclic aromatic hydrocarbons using ground and satellite data in Iran

Recently, for quick urbanization and industrialization, pollutants, especially urban dust, have posed many threats to the human environment. Polycyclic aromatic hydrocarbons (PAHs) are regarded as the main dangerous pollutants that are widespread, persistent, and carcinogenic. The present work aimed to investigate the contamination and sources of PAHs, as well as to assess the risk of cancer for 16 priority PAHs, in urban dust samples in Ahvaz, Isfahan, and Shiraz cities in Iran. We measured PAH concentrations by gas chromatography-mass spectrometry (GC-MS). The average concentrations of the 16 PAHs in Ahvaz, Isfahan, and Shiraz were 6215.11, 7611.03, and 7810.37 μg kg-1, respectively. The domination of low-molecular-weight (LMW) PAHs was observed in Ahvaz, while maximum contribution was observed for high-molecular-weight (HMW) PAHs in Esfahan and Shiraz. For PAHs' source identification, diagnostic ratio, correlation analysis, clustering, and positive matrix factorization (PMF) model were used. PAHs had a combustion (coal and wood, oil, fossil fuels) and gasoline/diesel engine emissions in all cities. Comparative studies suggest that the PAH compounds' level is higher in the research area than in other countries, except for China and India. Also, the pollution of urban dust PAHs has increased over time compared to previous studies in the same cities. The cancer risk from exposure to dust contaminated with PAHs was assessed using the Incremental Lifetime Cancer Risk (ILCR) model. According to the findings, a high risk of exposure to cancer was observed in Ahvaz, Isfahan, and Shiraz. However, compared to adults, children are at higher risk of cancer in their daily lives via dermal contact and unconscious ingestion. Based on the ILCR values, the risk of cancer is in the order of Shiraz > Isfahan > Ahvaz. To assess air pollutants and their effects on urban dust, TROPOMI onboard the Sentinel-5P data were used in the studied cities during 2018-2021. The results show that Ahvaz has different high levels of CO compared to the other 2 cities. Also, Isfahan has different high levels of NO2 compared to the other 2 cities, but Shiraz has different low levels of O3. According to satellite time series data, the trend of the Aerosol Absorbing Index (AAI) has been increasing, while there was a decreasing trend in AAI from the beginning of the COVID-19 pandemic until 12 months later. Therefore, the natural and anthropogenic sources of urban dust PAHs have been increasing in all studied cities. Our findings show that PAH compounds in urban dust pose a significant threat to human health. Therefore, strategic management and planning are vital in reducing urban dust pollution.

Heavy metal contamination levels, source distribution, and risk assessment in fine sand of urban surface deposited sediments of Ekaterinburg, Russia

Urban surface deposited sediments (USDS) are unique indicators of local pollution that pose a potential threat to the living environment and human health. Ekaterinburg is a highly populated metropolitan area in Russia with rapid urbanization and industrialization activities. In Ekaterinburg's residential areas, about 35, 12, and 16 samples are represented by green zones, roads, driveways, and sidewalks, respectively. The total concentrations of heavy metals was detected using a chemical analyzer inductively coupled plasma mass spectrometry (ICP-MS). Zn, Sn, Sb, and Pb have the highest concentrations in the green zone, while V, Fe, Co, and Cu represent the utmost values on roads. Moreover, Mn and Ni are the prevailing metals in the fine sand fraction of driveways along with sidewalks. Broadly, the high pollution in the studied zones is generated by anthropogenic activities and traffic emissions. The potential ecological risk (RI) was observed in high risk (IR > 600), even though the results of all heavy metals reveal no adverse health effects from the considered noncarcinogenic metal for adults and children by different exposure pathways except the children's exposure to Co in case of the dermal contact, where the HI values of Co for children in the studied zones are higher than the proposed level (> 1). In all urban zones, the total carcinogenic risk (TLCR) values are predicted as a high potential inhalation exposure.

Contamination and source apportionment of metals in urban road dust (Jinan, China) integrating the enrichment factor, receptor models (FA-NNC and PMF), local Moran's index, Pb isotopes and source-oriented health risk

Contamination and source identifications of metals in urban road dust are critical for remediation and health protection. Receptor models are commonly used for metal source identification, whereas the results are usually subjective and not verified by other indicators. Here we present and discuss a comprehensive approach to study metal contamination and sources in urban road dust (Jinan) in spring and winter by integrating the enrichment factor (EF), receptor models (positive matrix factorization (PMF) and factor analysis with nonnegative constraints (FA-NNC)), local Moran's index, traffic factors and Pb isotopes. Cadmium, Cr, Cu, Pb, Sb, Sn and Zn were the main contaminants, with mean EFs of 2.0-7.1. The EFs were 1.0-1.6 times higher in winter than in spring but exhibited similar spatial trends. Chromium contamination hotspots occurred in the northern area, with other metal contamination hotspots in the central, southeastern and eastern areas. The FA-NNC results indicated Cr contamination primarily resulting from industrial sources and other metal contamination primarily originating from traffic emissions during the two seasons. Coal burning emissions also contributed to Cd, Pb and Zn contamination in winter. FA-NNC model-identified metal sources were verified via traffic factors, atmospheric monitoring and Pb isotopes. The PMF model failed to differentiate Cr contamination from other detrital metals and the above anthropogenic sources, largely due to the model grouping metals by emphasizing hotspots. Considering the FA-NNC results, industrial and traffic sources accounted for 28.5 % (23.3 %) and 44.7 % (28.4 %), respectively, of the metal concentrations in spring (winter), and coal burning emissions contributed 34.3 % in winter. Industrial emissions primarily contributed to the health risks of metals due to the high Cr loading factor, but traffic emissions dominated metal contamination. Through Monte Carlo simulations, Cr had 4.8 % and 0.4 % possibilities posing noncarcinogenic and 18.8 % and 8.2 % possibilities posing carcinogenic risks for children in spring and winter, respectively.

Adverse impacts of Asian dust events on human health and the environment-A probabilistic risk assessment study on particulate matter-bound metals and bacteria in Seoul, South Korea

This study aimed to assess the impact of Asian dust (AD) on the human health and the environment. Particulate matter (PM) and PM-bound trace elements and bacteria were examined to determine the chemical and biological hazards associated with AD days and compared with non-AD days in Seoul. On AD days, the mean PM10 concentration was ∼3.5 times higher than that on non-AD days. Elements generated from the Earth's crust (Al, Fe, and Ca) and anthropogenic sources (Pb, Ni, and Cd) were identified as major contributors to coarse and fine particles, respectively. During AD days, the study area was recognized as "severe" for pollution index and pollution load index levels, and "moderately to heavily polluted" for geoaccumulation index levels. The potential cancer risk (CR) and non-CR were estimated for the dust generated during AD events. On AD days, total CR levels were significant (in 1.08 × 10^-5-2.22 × 10^-5), which were associated with PM-bound As, Cd, and Ni. In addition, inhalation CR was found to be similar to the incremental lifetime CR levels estimated using the human respiratory tract mass deposition model. In a short exposure duration (14 days), high PM and bacterial mass deposition, significant non-CR levels, and a high presence of potential respiratory infection-causing pathogens (Rothia mucilaginosa) were observed during AD days. Significant non-CR levels were observed for bacterial exposure, despite insignificant levels of PM10-bound elements. Therefore, the substantial ecological risk, CR, and non-CR levels for inhalation exposure to PM-bound bacteria, and the presence of potential respiratory pathogens, indicate that AD events pose a significant risk to both human lung health and the environment. This study provides the first comprehensive examination of significant non-CR levels for bacteria and carcinogenicity of PM-bound metals during AD events.

Assessment of metal pollution and human health risks in road dust from mineral rich zone of East Singhbhum, India

A detailed study of heavy metals in the road dust of a mineral rich zone of Jharkhand state, India is reported herein. Metal concentrations in the road dust exceeded the corresponding values in the average shale as well as world average of soil. Metal pollution due to the road dust and the possible health impact arising there from was appraised through a number of indices such as Geo-accumulation Index (I_geo), Pollution Load Index, Enrichment Factor (EF), Contamination Factor and US EPA Hazard Index and Cancer Risk. Cu contamination was highest as per EF and Igeo, followed by Pb and Zn. Aggravated heavy metal loading in the road dust was conspicuous in the proximity of copper mines and processing units. Both geogenic and anthropogenic sources were responsible for heavy metals in road dust according to principal component analysis. Hazard Quotient, Hazard Index and Cancer Risk were calculated to ascertain non-carcinogenic and carcinogenic health risks in adults and children. Local inhabitants, particularly children, were under appreciable cancer and non-cancer risk. Oral ingestion was the major pathway for risk to the local commuters followed by dermal pathway. Present study underscored the importance of regular heavy metal monitoring of road dust in this zone and administer proactive road dust management practices to reduce metal pollution.

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.

Heavy metal content in soil-like fractions on the landfills within Volgograd boundaries and assessment of health risk connected to its presence in the environment

The heavy metal content (Cu, Ni, Pb, Zn, and Cd) in a soil-like fraction from two landfills located within the boundaries of Volgograd was described using pollution indices and health risks. The calculated pollution index (PI) values have shown a lack of Pb and Zn pollution in the soil-like fraction from both landfills. For landfill No.1, the pollution level was determined as very high for Cd and as low for Cu and Ni, and for landfill No.2, this level was determined as very high, low, and non-polluted, respectively. The Nemerov integral pollution index (NIPI) values (25.24-43.90 for landfill No. 1 and 10.37-40.38 for landfill No. 2) indicated a high level of pollution in a soil-like fraction with studied elements in both landfills. According to the calculated values of the hazard index (HI), which are significantly lower than 1 in all samples, there is no non-carcinogenic risk for children and adults associated with the presence of a soil-like fraction in the environment. The total potential carcinogenic risks (TCR) associated with the heavy metals in a soil-like fraction were determined to be high for both target groups. The health of a child target group (TCR = 1.30E-03 and 4.87E-04) was found to be more exposed to carcinogenic risk than an adult target group (TCR = 1.40E-04 and 5.21E-05). Because the risk of a carcinogenic effect is high, the use of a soil-like fraction from both landfills for territory reclamation without prior detoxification is not allowed.

Mitochondrion Participated in Effect Mechanism of Manganese Poisoning on Heat Shock Protein and Ultrastructure of Testes in Chickens

Manganese (Mn) poisoning can happen in the case of environmental pollution and occupational exposure. However, the underlying mechanisms of Mn-induced teste toxicity and whether mitochondrion and heat shock proteins (HSPs) are involved in toxic effect of Mn on chicken testes remain poorly understood. To investigate this, MnCl₂·4H₂O was administered in the diet (600, 900, and 1800 mg/kg Mn) of chickens for 30, 60, and 90 days. Electron microscopy and qPCR were performed. Results showed that Mn exposure suppressed dose- and time-dependently HSP40 and HSP60 mRNA levels, meanwhile increased does-dependently HSP27, HSP70, and HSP90 mRNA levels at all three time points under three Mn exposure concentrations. Furthermore, Mn treatment damaged myoid cells, spermatocytes, and Sertoli cells through electron microscopic observation, indicating that Mn treatment damaged chicken testes. In addition, abnormal shapes of mitochondria were found, and mitochondria displayed extensive vacuolation. The increase of HSP90 and HSP70 induced by Mn exposure inhibited HSP40 and stimulated HSP27, respectively, in chicken testes, which needs further to be explored. Taken together, our study suggested that there was toxic effect in excess Mn on chickens, and HSPs and mitochondria were involved in the mechanism of dose-dependent injury caused by Mn in chicken testes. This study provided new insights for Mn toxicity identification in animal husbandry production practice.

A comprehensive review on pollution status and associated health risk assessment of human exposure to selected heavy metals in road dust across different cities of the world

In order to expound on the present situation and potential risk of road dust heavy metals in major cities, a total of 114 literatures mainly over the past two decades, involving more than 5000 sampling sites in 61 cities of 21 countries, were screened through the collection and analysis of research papers. The concentration, sources, distribution, health risk, sample collection, and analytical methods of heavy metal research on road dust in cities around the world are summarized. The results show that Cd, Zn, and Cu in many urban road dusts in the world are higher than the grade II of the Chinese maximum allowable concentration of potentially toxic elements in the soil. Geo-accumulation index values show that Pb > Cd > Zn > Cu had the highest contamination levels. Hazard index assessment indicates Pb and Cr had the highest potential health risk, especially for children in which ingestion was found as the main exposure pathway. Moreover, through comparative analysis, it is found that some pollutants are higher in developed and industrialized cities and transport (53%) followed by industrial emissions (35%) provide the major contributions to the sources of heavy metals.

Baseline concentrations, source apportionment, and probabilistic risk assessment of heavy metals in urban street dust in Northeast Brazil

Heavy metal pollution by accelerating urbanization is an emerging socio-environmental issue that poses a potential risk to human health and the environment. In this scenario, street dust is a primary source of contaminants. Here, the metal concentrations in street dust of one of the biggest Brazilian cities were assessed aiming to identify and quantify the sources of contamination. The metal bioaccessibility and estimated probabilistic (non)-carcinogenic risks to humans were also evaluated. Thirty-six dust samples were collected in the metropolitan region of Recife. Results showed that the traffic governed the distribution and accumulation of metals in street dust. Emissions from vehicles were the primary source (> 70 %) of heavy metals, except for Cd, which had a mixed origin (natural, traffic, and industrial). Moderate to heavy dust contamination by Ba, Cu, Mn, Pb, and Zn were found, with a very high potential ecological risk. The main exposure route depended on the metal. Barium, Cu, and Pb had ingestion rather than dermal contact as the main route of exposure, while inhalation and dermal contact posed the main risks to Mn and Cr, respectively. The risk for children was higher than for adults. The probabilities of unacceptable carcinogenic risk scenarios (TCRI >10-6) for children and adults were 27 and 4 %, respectively, with Cr being the most concerning metal for the health of the urban population.

Pollution characteristics and health risks of heavy metals in road dust in Ma'anshan, China

Road dust contains various heavy metals, which are re-suspension in the air under the action of wind and other external forces, threatening people's health all the time. Road dust was collected in the industrial heavy traffic area (IHT), non-industrial heavy traffic area (HT), urban area (UA), and study recreation area (SR) of Ma'anshan. The pollution degree of heavy metals in the four areas was calculated and demonstrated IHT > HT > UA > SR. In addition to the Ni (24.24 mg kg^-1)metals, the metals concentrations of Cr (74.14 mg kg^-1), Cu (91.8 mg kg^-1), Zn (393.03 mg kg^-1), Cd (9.93 mg kg^-1), and Pb (72.85 mg kg^-1) were all higher than the local soil background values. Cu comes from traffic emissions, Pb, Cd, and Zn mainly come from industrial emissions, as well as traffic emissions. While Cr and Ni mainly come from industrial emissions and local soil re-suspension. The non-carcinogenic risk of each heavy metal to children is 10 times higher than that of adults. Among them, the non-carcinogenic risk of Cr, Cd, and Pb to children is close to 1, so great attention should be paid to it. According to the study of enrichment factor (EF) and geo-accumulation index (I_geo), Cd is extremely polluted and it is imperative to reduce Cd pollution.

Elemental imaging approach to assess the ability of subaerial biofilms growing on constructions located in tropical climates as potential biomonitors of atmospheric heavy metals pollution

Over the last decades, the concern about air pollution has increased significantly, especially in urban areas. Active sampling of air pollutants requires specific instrumentation not always available in all the laboratories. Passive sampling has a lower cost than active alternatives but still requires efforts to cover extensive areas. The use of biological systems as passive samplers might be a solution that provides information about air pollution to assist decision-makers in environmental health and urban planning. This study aims to employ subaerial biofilms (SABs) growing naturally on façades of historical and recent constructions as natural passive biomonitors of atmospheric heavy metals pollution. Concretely, SABs spontaneously growing on constructions located in a tropical climate, like the one of the city of Barranquilla (Colombia), have been used to develop the methodological approach here presented as an alternative to SABS grown under laboratory conditions. After a proper identification of the biocolonizers in the SAB through taxonomic and morphological observations, the study of the particulate matter accumulated on the SABs of five constructions was conducted under a multi-analytical approach based mainly on elemental imaging studies by micro Energy Dispersive X-ray fluorescence spectrometry (μ-EDXRF) and Scanning Electron Microscopy coupled with Energy Dispersive X-ray spectrometry (SEM-EDS) techniques, trying to reduce the time needed and associated costs. This methodology allowed to discriminate metals that are part of the original structure of the SABs, from those coming from the anthropogenic emissions. The whole methodology applied assisted the identification of the main metallic particles that could be associated with nearby anthropogenic sources of emission such as Zn, Fe, Mn, Ni and Ti by SEM-EDS and by μ-EDXRF Ba, Sb, Sn, Cl and Br apart others; revealing that it could be used as a good alternative for a rapid screening of the atmospheric heavy metals pollution.

Potentially harmful elements in urban surface deposited sediment of Ekaterinburg, Russia: Occurrence, source appointment and risk assessment

In this study, the human health risks of potentially harmful elements (PHEs) in urban surface deposited sediments (USDS) were examined by collecting urban dust samples, measuring their PHE concentrations, and using index evaluation. About 35, 12 and 16 samples are represented a green zones, roads, driveways and sidewalks in residential areas of Ekaterinburg, respectively. The dust fraction (0.002-0.1 mm) was obtained by sieving, filtration, and decantation process. Total concentrations of 10 PHEs were measured using inductively coupled plasma mass spectrometry. The highest concentrations of Pb were found in USDS from green zones, while Fe, V, Mn, Co, Ni, Sn, and Sb on roads, Cu and Zn on driveways and sidewalks. The contamination levels in the investigated land-use areas were studied, where the highest contamination was contributed from Sb in the driveways and sidewalk. Moreover, the pollution in the studied zones was a high load, contributing to anthropogenic activities and traffic emissions. No non-cancerogenic risk was attributed from the PHEs based on the results of health indices (HI < 1) for both adult and children, except Co and Ni which has HI > 1 for children. The total carcinogenic risk (TLCR) in all urban landscape areas is defined as a high potential inhalation exposure and a low potential ingestion and dermal exposure.

Characterization, source apportionment and risk assessment of PAHs in urban surface dust in Shenyang city, China

Characteristics, profile composition, ecological and human health risk of polycyclic aromatic hydrocarbons in surface dust collected from Shenyang city, China, were investigated. Concentrations of 16 USEPA priority PAHs ranged between 371.57 and 3300.04 μg/kg (mean 1244.76 ± 715.25 μg/kg). Fluoranthene was the most abundant individual PAHs, followed by pyrene, and high molecular weight PAHs, more than three times of low molecular weight PAHs, were the predominant components. Profiles of PAHs showed that 4-ring PAHs were dominant, followed by 3-ring and 5-ring PAHs, and indicated that combustion sources accounted for the most PAHs. Results of diagnostic ratios and positive matrix factorization all suggested that pyrogenic sources were the most important source of PAHs in urban dust, followed by natural gas combustion and petrogenic sources, and traffic emissions would play an increasingly critical role with the increasing of vehicles. Health risk assessment suggested children were the most vulnerable to PAHs compared to adolescents and adults. Ingestion was the most important exposure pathway. The total lifetime cancer risk of 43.33% of sampling sites was higher than 10^-6, but the TLCR at all sites was much lower than the highest acceptable risk established by USEPA (10^-4).

Metal contamination in soils and windowsill dusts: implication of multiple sources on dust metal accumulation within a city affected by Pb smelting

The accumulation of total Pb, Cd, Cu, and Zn in soils (0-5 cm) and windowsill dust fractions (45-125, 10-45, and < 10 μm), and soil pollution indices (PI), were investigated in a long-term (~ 70 years) Pb smelter area and in the nearby urban city of Jiyuan, China. Principal component analysis (PCA) was utilized to identify metal contamination sources. Results showed that mean soil Pb, Cd, Cu, and Zn concentrations in the smelter area were 803, 13.8, 118, and 323 mg kg^-1, while those of the urban area were 270, 7.95, 51.6, and 244 mg kg^-1, respectively. Lead and Cd had greater soil PI than Cu and Zn. Lead concentrations in the 45-125, 10-45, and < 10-μm urban dust fractions ranged from 197.1 to 1953 (mean 1020), 202-3962 (2407), and 51.1-1258 (310.7) mg kg^-1, while Cd concentrations ranged from 11.1 to 111 (49.2), 10.4-159 (64.3) and 21.5-131 (60.0) mg kg^-1, respectively. Excessive Zn concentrations (5000-22,000 mg kg^-1) in some urban dust samples were found at two sampling sites, while Zn concentrations were < 2600 mg kg^-1 in all other samples. Based on PCA results, metal accumulation near the Pb smelter was dominated by smelting activities. The PCA results further suggested that mass vehicular transportation modes may be an important source of metals such as Cu and Zn in the urban area. Certain samples in both sub-areas had unsafe potential non-carcinogenic risks of Pb for children. These findings suggest that reducing environmentally relevant metal concentrations in this, and similar areas, will likely require a multi-faceted approach.

Tracing of Heavy Metals Embedded in Indoor Dust Particles from the Industrial City of Asaluyeh, South of Iran

Assessment of indoor air quality is especially important, since people spend substantial amounts of time indoors, either at home or at work. This study analyzes concentrations of selected heavy metals in 40 indoor dust samples obtained from houses in the highly-industrialized Asaluyeh city, south Iran in spring and summer seasons (20 samples each). Furthermore, the health risk due to exposure to indoor air pollution is investigated for both children and adults, in a city with several oil refineries and petrochemical industries. The chemical analysis revealed that in both seasons the concentrations of heavy metals followed the order of Cr > Ni > Pb > As > Co > Cd. A significant difference was observed in the concentrations of potential toxic elements (PTEs) such as Cr, As and Ni, since the mean (±stdev) summer levels were at 60.2 ± 9.1 mg kg−1, 5.6 ± 2.7 mg kg−1 and 16.4 ± 1.9 mg kg−1, respectively, while the concentrations were significantly lower in spring (17.6 ± 9.7 mg kg−1, 3.0 ± 1.7 mg kg−1 and 13.5 ± 2.4 mg kg−1 for Cr, As and Ni, respectively). Although the hazard index (HI) values, which denote the possibility of non-carcinogenic risk due to exposure to household heavy metals, were generally low for both children and adults (HI < 1), the carcinogenic risks of arsenic and chromium were found to be above the safe limit of 1 × 10−4 for children through the ingestion pathway, indicating a high cancer risk due to household dust in Asaluyeh, especially in summer.

Characteristics, source apportionment and health risk assessment of heavy metals in urban road dust of the Pearl River Delta, South China

To investigate the characteristics of heavy metals (As, Cd, Cr, Cu, Pb, Hg, Ni and Zn) in urban road dust from different cities and functional areas in the Pearl River Delta (PRD), South China, a total of 294 dust samples were analyzed. The contamination characteristics and health risk of heavy metals in the dust were assessed, their chemical speciation were distinguished, and their sources were identified by the correlations, cluster and principal component analysis (PCA). The mean concentrations of As (15.89 mg/kg), Cd (1.59 mg/kg), Cr (143.75 mg/kg), Cu (184.42 mg/kg), Pb (114.82 mg/kg), Hg (0.11 mg/kg), Ni (41.53 mg/kg) and Zn (645.94 mg/kg) in urban road dust were in high or moderate levels compare with other previous researches. In this case, the contamination of Cr, Cu, Ni and Zn in the industrial area (IA) and the contamination of Cd and Hg in the commercial area (CA) were significantly higher relative to other functional areas (P < 0.05), and the contamination of heavy metals in Foshan City was significantly higher than other cities (P < 0.01). The order of mobility of the heavy metals with higher concentration in urban road dust of the Pearl River Delta declined in the following order: Zn, Ni, Cu, Pb and Cr. Statistical analysis result showed the contaminated heavy metals in urban road dust were mainly contributed by industrial activities, traffic activities and building pollution. There were no significant carcinogenic and noncarcinogenic risks for adults, children however showed significant noncarcinogenic effect caused by As and Cr in partial points, albeit with low contamination level of the two metals. The ingestion was a principal pathway for heavy metals via urban road dust to exposure population. More protection measures should be considered to reduce children's exposure to the dust, especially in the CA and IA.

A global perspective of the current state of heavy metal contamination in road dust

Heavy metals are persistent and bio-accumulative, and pose potential risk to human health and ecosystem. We reviewed the current state of heavy metal contamination, the ecotoxicological and human health risk of heavy metals reported in urban road dust from various cities in different continents (Asia, Europe, Africa, America, and Australia). We compared and synthesized the findings on the methods related to sample collection, extraction, analytical tools of heavy metals, their concentrations, level of contamination, ecological risk, non-carcinogenic risk, and carcinogenic risk in road dust. Concentrations of Pb, Zn, Cu, Ni, Cd, Cr, Mn, and Fe were found to be higher than their background values in soil. As expected, the contamination levels of the heavy metals varied extensively among cities, countries, continents, and periods. A high level of contamination is observed for Pb and Cd in road dust due to operating leaded gasoline and the old vehicle population. The highest Zn contamination was observed from road dust in Europe, followed by Asia, Africa, Australia, and America (North America and South America). Cu contamination and the pollution load index (PLI) is found to be the highest in Europe and lowest in Africa, with in-between values of PLI in American and African cities. The potential ecological risk on different continents was observed highest in Asia, followed by Europe, Australia, America, and Africa. A comparative assessment of non-carcinogenic risk for children indicated that Australia is the most susceptible country due to high heavy metal exposure in road dust, followed by Asia. However, there is no susceptible risk in European, African, and American cities. We did not observe any potential risk to adults due to non-carcinogenic metals. Carcinogenic risk to all age groups was within the threshold limit range for all the regions worldwide.

Estimation of Ecological and Human Health Risks Posed by Heavy Metals in Street Dust of Madrid City (Spain)

In this work, sampling was carried out in the urban area of Madrid to analyze the content of total heavy metals (Zn, Pb, Cu, Cr, Ni, and Cd) in the street dust. Contamination was evaluated using various indices, such as the Contamination Factor (CF), Enrichment Factor (EF), Geo-accumulation Index (Igeo), Potential Ecological Risk Index (RI), Pollution Load Index (PLI), the Human Health Index Hazard Index (HI), and Cancer Risk (CR). Pollution indices were related to traffic density and color. Traffic density was the factor that most influenced the values of the pollution indexes, but no significant differences were found with the color of street dust. The concentration of heavy metals in the urban dust of Madrid had the following sequence: Zn (895) > Cu (411) > Pb (290) > Cr (100) > Ni (42) > Cd (1.25 mg kg−1). The pollution levels were high or very high in Pb, Zn, and Cd regarding the environmental pollution indexes. Ingestion was the main route of exposure to heavy metals contained in street dust. The CR for adults and children is less than 1 × 10−6, which means that there is no risk for the population. However, the HI was 10 times higher in children than in adults.

Source apportionment and health risk assessment for potentially toxic elements in size-fractionated road dust in Busan Metropolitan City, Korea

Potentially toxic elements' (PTEs; V, Cr, Co, Ni, Cu, Zn, As, Cd, Sb, Pb, and Hg) pollution level was investigated in size-fractionated road dust in Busan Metropolitan City. Health risks to humans (adult and children) were also evaluated in fine particle fraction (< 63 μm) of road dust. PTE concentrations in the fine particles (< 63 μm) were ranked as follows (unit: mg/kg): Zn (2511) > Cu (559) > Cr (531) > Pb (385) > Ni (139) > V (83.8) > Sb (31.6) > Co (21.6) > As (17.2) > Cd (4.1) > Hg (0.38). The PTE concentrations in fine particles (< 63 μm) were significantly higher than those in coarse particles except for V, Co, and As. The mean PTE loadings of fine particle fraction (< 63 μm; 233 mg/m2) in road dust were up to 4.5 times higher than other particle fractions. Igeo values of Sb were higher than 5 except for > 1000-μm fraction, indicating extremely polluted status. PCA results and elemental ratios indicated that most of the PTEs in road dust were derived from non-exhaust traffic-related sources such as brake pads and tires. Cr, Pb, and Sb had higher HI values than other metals for both adults and children. Sampling sites of heavy traffic and industrial areas showed that the carcinogenic risk exceeded the maximum threshold level (10 - 4). Especially in children, the mean carcinogenic risk (ingestion pathway) of As (6.8 × 10 - 4) Cd (2.0 × 10 - 4), and Ni (4.1 × 10 - 4) exceeded the maximum threshold level, indicating that continuous exposure to road dust may pose a high cancer risk to children. Therefore, continuous monitoring and management of these metals are needed to protect human health and the urban environment.

Characteristics and Health Risk Assessment of Mercury Exposure via Indoor and Outdoor Household Dust in Three Iranian Cities

This study aims to increase our current knowledge on the concentration of particulate-bound mercury (PBM) in urban environments of three Iranian cities, where high concentrations of dust particles can act as carriers for mercury transport and deposition. A total of 172 dust samples were collected from Ahvaz, Asaluyeh, and Zabol residential houses and in outdoor air and were analyzed for total mercury content. Ahvaz is a highly industrialized city with large metallurgical plants, refineries, and major oil-related activities, which were assumed to contribute to elevated contents of PBM in this city. Very high levels of Hg contamination in Ahvaz indoor dust samples were calculated (Contamination Factor: CF > 6). Sampling sites in Asaluyeh are influenced by Hg emissions from the South Pars Gas Field. However, the results revealed a relatively lower concentration of PBM in Asaluyeh, with a low-to-moderate level of Hg contamination. This is likely ascribed to the lower content of total mercury in hydrocarbon gases than crude oil, in addition to the absence of metal smelting plants in this city compared to Ahvaz. Zabol, as a city devoid of industrial activity, presented the lowest levels of PBM concentration and contamination. Indoor dust in Ahvaz showed considerable potential to cause a non-carcinogenic health risk for children, mainly through the inhalation of PBM, while the health risk for other cities was below safe limits. The trend of health risk was found in the order of indoor > outdoor and children > adults in all studied cities.

Sources of airborne particulate matter-bound metals and spatial-seasonal variability of health risk potentials in four large cities, South Korea

Fifteen airborne particulate matter-bound metals were analyzed at 14 sites in four large cities (Seoul, Incheon, Busan, Daegu) in South Korea, between August 2013 and June 2017. Among the seven sources resolved by positive matrix factorization, soil dust and marine aerosol accounted for the largest and second largest portions in the three cities; however, in Seoul, soil dust and traffic occupied the largest and the second largest, respectively. Non-carcinogenic risk assessed by inhalation of eight metals (Cd, Co, Ni, Pb, As, Al, Mn, and V) was greater than the hazard index (HI) of 1 at four sites located at or near the industrial complexes. Cumulative incremental lifetime cancer risk (ILCR) due to exposure to five metals (Cd, Co, Ni, Pb, and As) exceeded the 10^-6 cancer benchmark at 14 sites and 10^-5 at six sites, which includes four sites with HI greater than 1. The largest contributor to ILCR was coal combustion in Seoul, Incheon, and Daegu, and industry sources in Busan. Moreover, industry sources were the largest contributors to non-carcinogenic risk in Seoul, Busan, and Daegu, and soil dust was in Incheon. Incheon had the highest HI in spring because of the higher contribution of soil dust sources than in other seasons. The higher ILCR in Incheon in spring and winter and higher ILCR and HI in Daegu in autumn were mainly due to the influence of industry or coal combustion sources. Statistically significant differences in the ILCR and HI values among the sampling sites in Busan and Daegu resulted from the higher contribution of industry sources at a certain site in the respective city.

Road dust-driven elemental distribution in megacity Dhaka, Bangladesh: environmental, ecological, and human health risks assessment

Road dust, which reflects ambient air quality, receives various pollutants including toxic metal(oid)s from several natural and/or anthropogenic sources. This manuscript reports a comprehensive evaluation of the levels of seventeen metal(oid)s in road dust of a megacity (Dhaka, Bangladesh). Different evaluation approaches were implemented including statistical analysis and GIS mapping, besides environmental, ecological, and human health risk indices. From 30 sampling sites, representative samples were collected, which were analyzed by neutron activation analysis. The average concentrations (± SD) of Na, Mg, Al, Sc, Ti, V, Cr, Mn, Fe, Co, Zn, As, Rb, Sb, Cs, Ba, and W were 11,738 ± 560 µg g^-1, 12,410 ± 1249 µg g^-1, 62,127 ± 5937 µg g^-1, 8.89 ± 0.47 µg g^-1, 5224 ± 1244 µg g^-1, 66 ± 8 µg g^-1, 66.7 ± 6.9 µg g^-1, 547 ± 110 µg g^-1, 25,150 ± 1723 µg g^-1, 8.39 ± 0.65 µg g^-1, 125 ± 17 µg g^-1, 3.63 ± 0.56 µg g^-1, 87 ± 9 µg g^-1, 0.75 ± 0.28 µg g^-1, 4.40 ± 0.48 µg g^-1, 397 ± 87 µg g^-1, and 3.82 ± 1.77 µg g^-1, respectively. The distance-based redundancy analysis showed that the northern region was enriched with Na, Mn, Al, Fe, Zn, and Rb, while the southern region was enriched with Fe, Al, Ti, Cr, and Mg. The GIS mapping shows hot spots of Sc, Cr, Zn, and Cs were observed mostly in heavy traffic areas. Significant positive correlations of Fe-Sc, Al-Mg, V-Mg, V-Al, Cs-Rb, Cs-Sc, Rb-Sc, As-Na, and Cs-Rb invoked their inter-dependency and persistence in road dust. Depending on a set of environmental and ecological index-based calculation, the degree of metal(oid) pollution followed the descending order as W > Sb > Zn > Cr > As > Ti > Sc > V, while no pollution was recorded by Mn, Fe, Al, Rb, Cs, Co, and Ba. Importantly, the total hazard index values for adults and children were higher than unity, indicating potential non-carcinogenic health risks from exposure of road dust. Furthermore, the total carcinogenic risks from Cr and As through ingestion and dermal contact exceeded the standard guideline values. The implementation of different evaluation approaches strengthens the findings of metal(oid) source apportionment.

Assessing the contamination level, sources and risk of potentially toxic elements in urban soil and dust of Iranian cities using secondary data of published literature

Research in urban geochemistry has been expanding globally in recent years, following the trend of the ever-increasing human population living in cities. Environmental problems caused by non-degradable pollutants such as metals and metalloids are of particular interest considering the potential to affect the health of current and future urban residents. In comparison with the extensive global research on urban geochemistry, Iranian cities have not received sufficient study. However, rapid and often uncontrolled urban expansion in Iran over recent years has contributed to an increasing number of studies concerning contamination of urban soil and dust. The present work is based on a comprehensive nationwide evaluation and intercomparison of published quantitative datasets to determine the contamination levels of Iranian cities with respect to potentially toxic elements (PTEs) and assess health risks for urban population. Calculation of geoaccumulation, pollution, and integrated pollution indices facilitated the identification of the elements of most concern in the cities, while both carcinogenic and non-carcinogenic risks have been assessed using a widely accepted health-risk model. The analysis of secondary, literature data revealed a trend of contamination, particularly in old and industrial cities with some alarming levels of health risks. Among the elements of concern, As, Cd, Cu, and Pb were found to be most enriched in soils and dusts of the studied cities based on the calculated geochemical indices. The necessity of designing strategic plans to mitigate possible adverse effects of elevated PTE concentrations in urban environments is emphasized considering the role of long-term exposure in the occurrence of chronic carcinogenic and non-carcinogenic health problems.

Human health risk assessment of lead (Pb) through the environmental-food pathway

Drinking water and farm-to-fork pathways have been identified as the predominant environmental pathways associated with human exposure (HE) to Pb. This study integrates a GIS-based survey of metal concentrations in soil and a probabilistic quantitative risk assessment of Pb through the food chain. The case study area was selected in the east of Ireland. A step-wise exposure assessment collated the data for Pb concentration in soil and water media, bioaccumulation of Pb in unprocessed food products, such as potatoes, carrots, green vegetables, and salad vegetables. The daily mean HE to Pb through selected food products was found to be 0.073 mg day^-1, where a mean weekly exposure was estimated as 0.0065 mg kg body weight^-1 week^-1. Multiple risk estimates were used. Hazard Quotient (HQ), Daily Dietary Index (DDI), Daily Intake of Metal (DIM), Health Risk Index (HRI), Target Hazard Quotient (THQ) and Cancer Risk (CR) were found as 0.234 to 0.669, 0.002, 0.0002, 0.020 to 0.057, 0.234 to 0.669, and 0.00001, respectively which signify a low to moderate risk. A sensitivity analysis revealed that intake of potato is the most sensitive parameter of the model, which is positively correlated (coeff. + 0.66) followed by concentration of Pb in the arable soil (+0.49), bioaccumulation in tubers (+0.37), consumption of salad vegetables (+0.20), and consumption of green vegetables (+0.13) (top 5). A back-calculated limit of Pb in the soil (51 mg kg^-1) justifies the lower threshold limit of Pb (50-300 mg kg^-1) in agricultural soil set by the European Union to mitigate potential bio-transfer into food products. The study concludes there is a low to moderate risk posed by Pb, within the system boundary of the probabilistic model, and highlights the significance of limiting Pb concentrations in the vegetable producing agricultural soil.

Polycyclic aromatic hydrocarbons in street dust from different functional areas in Chengdu, China: seasonal variation and health risk assessment

This is the first investigation that identified seasonal variation, possible sources and health risk of 16 PAHs in street dust sampled park area (PA), educational area (EA), commercial area (CA), residential area (RA), and traffic area (TA) of Chengdu, one of the new first-tier cities in China. The total PAHs (∑₁₆PAHs) concentrations of averaging over two seasons varied from 2.15 to 10.6 mg/kg with a median value of 4.61 mg/kg and in winter (5.48 ± 1.52 mg/kg) were significantly higher than that in summer (4.04 ± 0.91 mg/kg). The highest ∑16PAHs concentration was found in TA (median 6.74 mg/kg). Statistical analysis results indicated that mixture sources of petroleum combustion and combustion of biomass and coal seem to be the primary source of the PAHs in street dust. Carcinogenic risk by incremental lifetime cancer risk (ILCR) model for PAHs in street dust indicates an acceptable potential cancer risk for residents. The same sequences of cancer risk to be observed for both children and adults among different functional areas: TA > CA > EA > RA > PA. The results provided advice for habitants in Chengdu to encourage outdoor activities in parks and residential areas and minimize traffic areas and commercial areas.

Seasonal source identification and source-specific health risk assessment of pollutants in road dust

Humans who are exposed to metals in road dust may have potential health risks through touching, ingesting, and inhaling the suspended road dust. There were limited studies to link seasonal emission sources to health risks from metals in road dust. In this study, metals in road dust from different functional areas were seasonally monitored. The contributions of the pollutant sources in study areas varied with seasons. By combining the source apportionment model (PMF), road dust emission model, and health risk models (HI: hazard index and ILCR: incremental lifetime carcinogenic risk), industrial and construction activity was identified as the crucial source of both the pollutants in road dust (29-47%), and the HI for adults (27-45%) and children (41-50%) in different seasons. The traffic non-exhaust emission dominated in the carcinogenic risks for children in spring (45%) and summer (36%). Factors such as seasons, particle size, metal bioavailability, human exposure time, and exposure area were all taken into consideration to avoid overestimating or underestimating health risks. The carcinogenic risks for children (1.6 E-06) and adults (2.8 E-06) exposed to Cr both exceed the minimum threshold (10^-6). It means that the potential risks were acceptable but could not be completely neglected. Measured metals mainly posed hazard to human health through ingestion route. Pb and Mn, Fe and Mn were the main harmful elements that induced non-carcinogenic risks for adults and children, respectively. Effectively identifying the source-specific health risks in different seasons will help in the formulation of adaptive strategies to diminish the potential risks.

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.

Source identification of pollution and health risks to metals in household indoor and outdoor dust: A cross-sectional study in a typical mining town, China

Dust is regarded as an important pathway of heavy metal(loid)s to the human body. Health risks posed by metal(loid)s from household dust are of particular concern. However, the contamination and sources of heavy metal(loid)s in household dust environments, as well as source identification of health risks related to heavy metal(loid)s from household dust for vulnerable populations such as children, have not been thoroughly studied in China, particularly for the areas involved with industrial activities such as ore mining. Thus, a cross-sectional study was conducted in a rural area famous for Pb/Zn ore mining, to assess the pollution sources and health risks of heavy metal(loid)s from household indoor and outdoor dust and to identify the contribution of household dust to the health risks for children. The results indicated that household environment was heavily contaminated by metal(loid)s, which were mainly attributed to mining activity. Meanwhile, the indoor/outdoor ratio and the redundancy analysis indicated that there were other pollution sources in indoor environments such as coal combustion, materials for interior building and decoration. Vapor inhalation was the main exposure pathway for Hg, while ingestion was the predominant pathway for other metal(loid)s. Although the cancer risks were relatively low, the HIt from household indoor and outdoor dust (2.19) was about twice the acceptable limit (1) and was primarily from Pb (64.52%) and As (23.42%). Outdoor dust was a larger contributor to the HI of Sb, As, Cr, Cd, Zn and Pb, which accounted for 51.37%, 58.63%, 52.14%, 59.66%, 52.87% and 64.47%, respectively, and the HIt was mainly from outdoor dust (60.76%). These results indicated that non-cancer health risks were largely from outdoor dust exposure, and strengthened the notion that concern should be given to the potential health risks from metal(loid)s in household dust both originating from mining activity and indoor environmental sources.

Investigations of Metal Pollution in Road Dust of Steel Industrial Area and Application of Magnetic Separation

Pollution characteristics and ecological risks for metals in non-magnetic and magnetic road dust from steel industrial areas were investigated by applying a magnetic separation method. Metal (except for Al, Li, Ti, As, and Sb) concentrations in the magnetic road dust were 1.2 (Sn) to 7.8 (Fe) times higher than those in the non-magnetic road dust. For the magnetic road dust, the geo-accumulation index revealed a strongly to extremely polluted status for Cr, Zn, Cd, and Sb, a strongly polluted status for Mn, Cu, and Pb, and a moderately to strongly polluted status for Fe, Ni, Mo, and Hg. This result indicates that the dominant metal pollution sources of road dust in industrial areas were the traffic activities of heavy-duty vehicles. The mean content of magnetic particles accounted for 44.7% of the total road dust. The metal loadings in the magnetic road dust were 86% (Fe), 77% (Cr), 67% (Mn), 86% (Ni), 76% (Cu), 72% (Zn), 64% (Mo), and 62% (Cd), respectively. Removal of the magnetic fraction from road dust using magnetic separation techniques not only reduces metal contamination but can also improve effective road cleaning strategies or reduce waste generation.

Concentrations and transportation of metal and organochlorine pollutants in vegetables and risk assessment of human exposure in rural, urban and industrial environments (Bouches-du-Rhône, France)

The bioaccumulation of metals (As, Cd, Co, Cr, Cu, Ni, Pb, Sb, V, Zn, Al, Fe) and organochlorine compounds (PCDD-Fs and PCBs) was assessed in soils and vegetables of 3 sites of contrasted anthropogenic influence (rural and industrial-urban areas). Cultivated soils in industrial areas exhibited diffuse pollution in organochlorine pollutants (PCBs and PCDD-Fs). The pollutant levels encountered in vegetables were always lower than the EU regulatory or recommended values. However, the contents measured in vegetables cultivated near industrialized areas were significantly higher than those observed in rural areas. This was notably the case for Co, Cd, Cr, Ni, Pb, V, NDL- and DL-PCB, PCDD, and PCDF. The leaf pathway appeared as the main absorption pathway for many contaminants. The results suggested that population exposure to pollutants was mainly caused by vegetable ingestion. In the vegetables and soils, the toxicity was mainly caused by the V, Co, Cd, and Pb contents to which can be added As and PCDD-Fs for soils. Therefore, the proximity of vegetable crops to highly anthropised areas has led to long-term exposure of vegetables and soils to air pollutants, leading to an accumulation in the food chain and thus a risk for human health.

Trace element-based geochemical contamination characteristics and potential risks to human health: a case study from Northeast Turkey

Trace elements measured in Artvin province soil samples in Northeast Turkey were assessed using pollution and health indices. The study area is positioned in one of the essential metallogenic belts in Turkey. This attempt is the first endeavor toward the study area in this context. The measured trace elements are As, Co, Cr, Cu, Mn, Ni, Pb and Zn, as they were assessed using pollution indices, enrichment factor, geo-accumulation index, contamination factor, and health risk assessment methods. According to the results of enrichment factor (EF), geo-accumulation index (I_geo), and contamination factor (CF), the soils of Artvin province show a slightly severe enrichment, moderately polluted and very high contaminated with arsenic, respectively. The pollution load index score (PLI) index (1.57) indicates that Artvin province is polluted in terms of trace elements. The hazard index (HI) calculated values for children and adults were 1.55 and 0.18, respectively. This revealed that the aforementioned metals can have non-carcinogenic effects (HI > 1). Total potential carcinogenic health risk (TCR) values for children and adults were 3.22 × 10^-5 and 1.40 × 10^-5, respectively. The non-carcinogenic risk level indicates that there may be a risk for children rather than adults.

Characteristics and Risk Assessment of 16 Metals in Street Dust Collected from a Highway in a Densely Populated Metropolitan Area of Vietnam

The present study focused on investigating the contamination and risk assessment for 16 metals in street dust from Ha Noi highway, Ho Chi Minh City. The results indicated that the concentrations of metals (mg/kg) were found, in decreasing order, to be Ti (676.3 ± 155.4) > Zn (519.2 ± 318.9) > Mn (426.6 ±113.1) > Cu (144.7 ± 61.5) > Cr (81.4 ± 22.6) > Pb (52.2 ± 22.9) > V (35.5 ± 5.6) > Ni (30.9 ± 9.5) > Co (8.3 ± 1.2) > As (8.3 ± 2.5) > Sn (7.0 ± 3.6) > B (5.7 ± 0.9) > Mo (4.1 ± 1.7) > Sb (0.8 ± 0.3) > Cd (0.6 ± 0.2) > Se (0.4 ± 0.1). The geo-accumulation index (Igeo) showed moderate contamination levels for Pb, Cd, Cu, Sn, Mo, and Zn. The enrichment factor (EF) values revealed moderate levels for Cd, Cu, Mo, and Sn but moderate–severe levels for Zn. The pollution load index of the heavy metals was moderate. The potential ecological risk (207.43) showed a high potential. Notably, 40.7% and 33.5% of the ecological risks were contributed by Zn and Mn, respectively. These findings are expected to provide useful information to decision-makers about environmental quality control strategies.

Pollution characteristics and human health risk assessments of toxic metals and particle pollutants via soil and air using geoinformation in urbanized city of Pakistan

Toxic metals and particle pollutants in urbanized cities have significantly increased over the past few decades mainly due to rapid urbanization and unplanned infrastructure. This research aimed at estimating the concentration of toxic metals and particle pollutants and the associated risks to public health across different land-use settings including commercial area (CA), urban area (UA), residential area (RA), and industrial area (IA). A total of 47 samples for both soil and air were collected from different land-use settings of Faisalabad city in Pakistan. Mean concentrations of toxic metals such as Mn, Zn, Pb, Ni, Cr, Co, and Cd in all land-use settings were 92.68, 4.06, 1.34, 0.16, 0.07, 0.03, and 0.02 mg kg^-1, respectively. Mean values of PM₁₀, PM_2.5, and Mn in all land-use settings were found 5.14, 1.34, and 1.9 times higher than the World Health Organization (WHO) guidelines. Mn was found as the most hazardous metal in terms of pollution load index (PLI) and contamination factor (CF) in the studied area. Health risk analysis for particle pollutants using air quality index (AQI) and geoinformation was found in the range between good to very critical for all the land-use settings. The hazard quotient (HQ) and hazard index (HI) were higher for children in comparison to adults, suggesting that children may be susceptible to potentially higher health risks. However, the cancer risk (CR) value for Pb ingestion (1.21 × 10^-6) in children was lower than the permissible limit (1 × 10^-4 to 1 × 10^-6). Nonetheless, for Cr inhalation, CR value (1.09 × 10^-8) was close to tolerable limits. Our findings can be of valuable assistance toward advancing our understanding of soil and air pollutions concerning public health in different land-use settings of the urbanized cities of Pakistan.

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.

Can the contamination of urban street sediment be used as an indicator for traffic density? A case-study in the city of Leuven, Belgium

The concentration, in urban street sediment, of 13 chemical elements was measured in the city of Leuven, Belgium. A total of 77 locations were sampled in pedestrian zones, streets with limited traffic, streets with much traffic, and on the ring road that has very busy traffic. The data were compared to NO₂ concentrations measured by the CurieuzeNeuzen-Vlaanderen project, a large-scale study with 20,000 sampling points all over Flanders (the northern part of Belgium). NO₂ is a frequently used indicator for traffic pollution. In Leuven the highest enrichment (strongest pollution) was measured for Cu, Sb, Pb and Zn. These elements could be related to brake wear and tire wear, respectively. For Cu and Zn the concentrations in Leuven exceed those in most of the other cities investigated in the literature. Moderate enrichment was measured for Cd, Cr, Ni and S. The other elements (As, Co, Fe, Mn and V) showed concentrations close to the background value in unpolluted soil. The Integrated Pollution Index (IPI) for Leuven is 8.15, which, according to criteria proposed by the literature on street sediment, classifies Leuven, on average over its surface area, as a "very highly polluted" city. As expected, for Cu and Sb the highest contamination is found on the ring road and the busy traffic circulation loops. For Zn and Pb, on the other hand, the highest contamination occurs in the city center, in the pedestrian zone where no traffic is allowed except for buses and taxis. We hypothesize that this is a result of historic accumulation of these elements at the time traffic was still allowed in this zone. In Leuven the chemical composition of street sediment did not correlate to the NO₂ concentrations. This study shows that measurements of current pollution by traffic are not sufficient to determine the health risk because much exposure to toxic substances may be caused by resuspension, by traffic or wind, of substances that have accumulated in the city over time, sometimes decades ago, when regulations were much less stringent then today.