Heavy metals and polycyclic aromatic hydrocarbons: pollution and ecological risk assessment in street dust of Tehran

Ecological and human health risks of potentially toxic elements (PTEs) in street dust of Al-Hillah City, Iraq using Monte Carlo simulation

Street dust is a primary source of metal pollution in urban environments, posing a significant threat to human health through chronic exposure via inhalation, ingestion, and skin contact. This study used deterministic and Monte Carlo simulation to assess the health risks of potential toxic elements (PTEs) in the street dust of Al-Hillah City. The average concentrations of elements in the samples followed the order: Al > Fe > S > K > Sr > Mn > Cr > Ba > Zn > Ni > Pb > Cu > Co > As > Sn > Sb > Cd. In the study area, all the measured elements exceeded UCC values except for Al, Ba, Fe, and K. The results for the enrichment factor (EF), geo accumulation index (Igeo), and contamination factor (CF) revealed that the most sampled locations were polluted with sulfur (S), arsenic (As), and chromium (Cr). The highest values of the pollution load index were not for a solely land use class; they were identified at different sampling stations. According to the potential ecological risk rating, As and Cd pose a medium risk, while Cr, Cu, Ni, Pb, and Zn have low risks. The probabilistic Monte Carlo simulation highlighted the significant health risks from PTEs in street dust, especially for children, with HI values of 2.01, 3.24, and 5.26 at the 5th, 50th, and 95th percentiles, respectively. In comparison, HI values for adults were much lower at 0.29, 0.41, and 0.58, remaining within safe limits. Lifetime Cancer Risk (LTCR) estimates showed that 99.7 % of adults and 97 % of children exposed to levels exceeding the safe threshold 1E-4. Sensitivity analysis revealed that chromium (Cr) and nickel (Ni) were the main PTEs contributing to health risks in children and adults' groups.

A study of the direct emission of tire wear particles on different types of roads

In the range of 5-6 Mt/y tire wear particles (TWP) are emitted from vehicles in both developed and emerging countries. In an attempt to reduce these emissions, new regulations will come into force in the EU and USA, although currently no oversight methods are actually in place. This study proposes a method for assessing direct TWP emissions (TWPD) from vehicles. The method entails labeling the tire with mercury, then collecting and fractionating the particles emitted at the rear of the wheel (RoWP), and lastly analyzing their Hg content in the laboratory using atomic absorption spectroscopy. It provides access to the magnitude, size distribution and factors affecting TWPD emissions under actual driving conditions. Furthermore, the implementation of desorption and dispersion models allows evaluation of the proportion of TWPD embedded in tire and road wear particles (TRWP) and estimating the TWPD contribution to the lower atmosphere PM1, PM2.5 and PM10 pollution within the EU-27. A key finding of this research is that ultrafine TWPD (accounting for 33-260 mg/g of abraded front tire material) account for 30-70 % of total TWPD emissions (with >93 % being in the form of inclusions), although they make up 0.5-5.7 % of RoWP mass emissions. Our data also draw attention to the magnitude and lower TRWP-embedment of TWPD emissions in urban areas.

Spatial distribution, source apportionment, and health risks assessment of trace elements in pre- and post-monsoon soils in the coal-mining region of North Karanpura basin, India

Coal mining activities in the North Karanpura basin have significantly increased the trace element (TE) concentrations in the soil, resulting in soil pollution and potential health risks. To assess this, 113 soil samples, along with coal, shale, and overburden rocks, were collected from open-cast mining areas during pre-monsoon (Pre-M) and post-monsoon (Post-M) seasons. Seasonal analysis revealed higher TE concentrations in the Post-M period, especially in the SE direction, followed by NE and NW, likely due to surface runoff and deposition, demonstrating temporal variability in TE distribution which corroborated from the spatial distribution maps. Positive matrix factorization (PMF) model identified four factors: mixed sources (F1Pre-M: 37.6 %; F4Post-M: 28.9 %), coal-fired emissions (F2Pre-M: 20.5 %; F3Post-M: 26.0 %), overburden rocks (F3Pre-M: 25.5 %; F2Post-M: 16.7 %), and agricultural and lithogenic origin (F4Pre-M: 16.4 %) during the Pre-M period, attributed to coal mining. Post-M sources were similar, but agricultural and lithogenic origins were replaced by atmospheric deposition (F1Post-M: 28.4 %), enhanced by monsoon effects. Carcinogenic risk assessment revealed that As, Cr, and Ni exceeded acceptable levels for children via ingestion, though adults remained within safe limits. Inhalation and dermal contact were also considered, but ingestion posed the highest risk. The hazard index (HI) via ingestion showed that children had an HI of 1.6 in Pre-M, increasing to 2.66 in Post-M, highlighting their potential vulnerability to non-carcinogenic risks, while adults stayed within safe limits. The expansion of mining areas in the study region led to decrease in vegetative areas which could affect agriculture and local communities, raising a comprehensive environmental and public health issues. These results underline the need for implementing effective biannual soil monitoring and mitigation strategies, such as phytoremediation, bioremediation, rock dust remediation, chemical amendments and improved waste management, to reduce TE contamination.

Polycyclic aromatic hydrocarbons within the vicinity of a scrap-iron smelting plant: indoor-outdoor and seasonal pattern, source, and exposure risk assessment

The growing demand for ferrous metals and abundant scrap materials has fueled Nigeria's scrap-iron smelting industry, leading to hazardous pollutant emissions. This study investigated the concentrations, seasonal and indoor-outdoor variations, origins, and health impacts of polycyclic aromatic hydrocarbons (PAHs) in dust samples around a scrap-iron smelting facility. Analyses of dust samples revealed that high molecular weight PAHs (HMWPAHs) dominated during both seasons, with 5-ring PAHs (34%) contributing most during the rainy season and 3-ring PAHs (36%) during the dry season. Carcinogenic PAHs were more prevalent in the rainy season compared to the dry season. Seven PAH sources were identified, with gasoline combustion being the dominant source during the rainy season and iron and steel production during the dry season. Incremental lifetime cancer risk (ILCR) assessments showed PAH concentrations within safe limits, with dermal contact identified as the primary exposure pathway for both children and adults in the study area.

Exposure assessment of metal(loids) in indoor air and biomonitoring in six urban residential areas in Iran

Exposure to metal(loid)s can cause adverse health effects. This study evaluated the concentrations of aluminum, arsenic, cadmium, chromium, mercury, nickel, and lead in particulate matter <10 μm (PM10) and in the urine of 100 participants from urban residential areas in Iran. A total of 100 residential buildings (one adult from each household) in six cities across Iran were recruited for this study. The levels of metal(loid)s in PM10 and the urine of participants were measured using acid digestion followed by inductively coupled plasma mass spectrometry (ICP-MS). The average (±SE) PM10 concentration in the buildings was 51.7 ± 3.46 μg/m3. Aluminum and cadmium had the highest and lowest concentrations among the metal(loid)s, averaging 3.74 ± 1.26 μg/m3 and 0.01 ± 0.001 μg/m3, respectively. In 85 % of the samples, the concentration of metal(loid)s in indoor air exceeded WHO air quality standards. Cadmium and lead had the highest and lowest numbers of indoor air samples exceeding the recommended standards, respectively. A significant correlation was found between the concentration of metal(loid)s in urine samples and indoor PM10 levels, as well as the wealth index of participants. There was also a significant direct relationship between the concentrations of nickel, arsenic, lead, and mercury in urine and the age of participants. Factors such as building location, type of cooling systems, use of printers at home, and natural ventilation influenced the concentration and types of metal(loid)s in the indoor air.

Source-specific probabilistic health risk assessment of dust PAHs in urban parks based on positive matrix factorization and Monte Carlo simulation

Understanding the health risks of polycyclic aromatic hydrocarbons (PAHs) in dust from city parks and prioritizing sources for control are essential for public health and pollution management. The combination of Source-specific and Monte Carlo not only reduces management costs, but also improves the accuracy of assessments. To evaluate the sources of PAHs in urban park dust and the possible health risks caused by different sources, dust samples from 13 popular parks in Kaifeng City were analyzed for PAHs using gas chromatograph-mass spectrometer (GC-MS). The results showed that the surface dust PAH content in the study area ranged from 332.34 µg·kg-1 to 7823.03 µg·kg-1, with a mean value of 1756.59 µg·kg-1. Nemerow Composite Pollution Index in the study area ranged from 0.32 to 14.41, with a mean of 2.24, indicating that the overall pollution warrants attention. Four pollution sources were identified using the positive matrix factorization (PMF) model: transportation source, transportation-coal and biomass combustion source, coke oven emission source, and petroleum source, with contributions of 33.74%, 25.59%, 22.14%, and 18.54%, respectively. The Monte Carlo cancer risk simulation results indicated that park dust PAHs pose a potential cancer risk to all three populations (children, adult male and adult female). Additionally, the cancer risk for children was generally higher than that for adult males and females, with transportation sources being the main contributor to the carcinogenic risk. Lastly, sensitivity analyses results showed that the toxic equivalent concentration (CS) is the parameter contributing the most to carcinogenic risk, followed by Exposure duration (ED).

Hybrid machine learning approach integrating GMDH and SVR for heavy metal concentration prediction in dust samples

In agricultural regions prone to dust storms, heavy metal contamination of soil and crops from airborne particulates poses significant risks to food safety and public health. This study has assessed the potential of machine learning models for predicting concentrations of toxic heavy metals like arsenic, chromium, and lead in dust from the agricultural Sistan region of southeastern Iran. This region experiences frequent dust storms mobilizing particulates from local dried lakes onto agricultural lands. The metals including nickel, copper, magnesium, cobalt, zinc, chromium, arsenic, and lead were measured in summer dust samples during 2012-2018 across 15 stations. Two hybrid models were developed combining group method of data handling (GMDH) and support vector regression (SVR) machine learning with harmony search optimization (H) so as to predict toxic metals arsenic, chromium, and lead using nickel, copper, magnesium, cobalt, and zinc inputs. Standard error maps were uncertainty higher in southern and western areas, and they are most impacted by dust storms. Results demonstrated that the hybrid GMDH + H and SVR + H models improved the accuracy of individual GMDH and SVR models in predicting heavy metals. The GMDH + H model performed the best for the lead with an agreement index (d-index) of 0.98, root mean square error (RMSE) of 2.87 ppm, normalized RMSE (NRMSE) of 0.12, and coefficient of determination (RR) of 0.96. The SVR + H model showed the highest accuracy for arsenic and chromium, obtaining d-index 0.96, RMSE 0.47 ppm, NRMSE 0.09, and RR 0.92 for arsenic, and d-index 0.96, RMSE 11.24 ppm, NRMSE 0.16, and RR 0.93 for chromium. Taylor's diagram and heatmap analysis confirmed the superiority of the hybrid techniques. This work demonstrates the utility of state-of-the-art computing for addressing complex environmental health challenges.

Size-segregated content of heavy metals and polycyclic aromatic hydrocarbons in airborne particles emitted by indoor sources

Indoor air quality is negatively affected by the emission of different combustion sources releasing airborne particles and related particle-bound toxic compounds (e.g., heavy metals and polycyclic aromatic hydrocarbons). To date, very few studies focused on the chemical characterization of the airborne particles emitted by indoor sources were carried out; moreover, no data on their size-resolved chemical compositions are available. In the present study, an experimental analysis aimed at determining the size-segregated content of heavy metals and polycyclic aromatic hydrocarbons in airborne particles (including sub-micrometric ones) emitted by widely-used indoor combustion sources (i.e., incenses, candles, mosquito-coils, and cooking activities) was carried out. To this purpose, airborne particles were collected through an electric low-pressure impactor and were post-analyzed by means of chromatography-mass spectrometry and atomic emission spectrometry techniques. Results of the analyses showed that the chemical composition of the emitted particles is not invariant to the particle size, indeed, an important contribution of sub-micrometric particle range to the total mass of chemical compounds emitted by the sources was noticed. These findings also demonstrated that significant underestimations of particle-bound compounds depositing in the lungs could occur if size-dependent compositions are not adopted.

Health risk assessment of heavy metals in the dust street of Mehran city, as a busy city in religious times, Iran

The concentration of various potentially toxic metals (Pb, Cd, As, Ni, Zn, and Cr) in street dust samples collected from Mehran city, Iran, was analyzed. The samples were obtained during normal traffic conditions, NTT, prior to the Arbaeen ceremony, as well as after the pilgrims' return, which corresponds to high traffic time, HTT. Street dust samples were analyzed for HM content using ICP-OES, following acid digestion. The subsequent evaluation of the data involved the application of the geo-accumulation index, enrichment factor, and potential ecological risk index (PER) and health risk assessment. The findings demonstrate a notable increase in the levels of HMs during HTT compared to the NTT. The highest enrichment values for Pb and Cd were observed in Mehran Street dust during the HTT. The mean of PER for all sampling points increased to 138.24, indicating a moderate-potential ecological risk at this time. Based on the health risk assessment, it was found that the hazard index for all samples was below one. The incremental lifetime cancer risk was below 10-6. This indicates that the exposed population is not exposed to substantial health risks. Despite the heavy traffic caused by the Arbaeen ceremony in this area and the high enrichment of HMs, along with potential ecological risks, no significant health risks were observed for individuals exposed to street dust. However, it is important to note that the continuation of this trend, in the absence of proper traffic management, could lead to significant environmental and health problems in the future.

Application of machine learning and multivariate approaches for assessing microplastic pollution and its associated risks in the urban outdoor environment of Bangladesh

Microplastics (MPs) are an emerging global concern due to severe toxicological risks for ecosystems and public health. Therefore, this is the first study in Bangladesh to assess MP pollution and its associated risks for ecosystems and human health in the outdoor urban environment using machine learning and multivariate approaches. The occurrences of MPs in the urban road dust were 52.76 ± 20.24 particles/g with high diversity, where fiber shape (77%), 0.1-0.5 mm size MPs (75%), blue color (26%), and low-density polyethylene (24%) polymer was the dominating MPs category. Pollution load index value (1.28-4.42), showed severe pollution by MPs. Additionally, the contamination factor (1.00-5.02), and Nemerow pollution index (1.38-5.02), indicate moderate to severe MP pollution. The identified polymers based on calculated potential ecological risk (2248.52 ± 1792.79) and polymer hazard index (814.04 ± 346.15) showed very high and high risks, respectively. The occurrences of MPs could effectively be predicted by random forest, and support random vector machine, where EC, salinity, pH, OC, and texture classes were the influencing parameters. Considering the human health aspect, children and adults could be acutely exposed to 19259.68 and 5777.90 MP particles/ year via oral ingestion. Monte-Carlo-based polymers associated cancer risk assessment results indicate moderate risk and high risk for adults and children, respectively, where children were more vulnerable than adults for MP pollution risks. Overall assessment mentioned that Dhaka was the most polluted division among the other divisions.

Integrating deep learning and regression models for accurate prediction of groundwater fluoride contamination in old city in Bitlis province, Eastern Anatolia Region, Türkiye

Groundwater resources in Bitlis province and its surroundings in Türkiye's Eastern Anatolia Region are pivotal for drinking water, yet they face a significant threat from fluoride contamination, compounded by the region's volcanic rock structure. To address this concern, fluoride levels were meticulously measured at 30 points in June 2019 dry period and September 2019 rainy period. Despite the accuracy of present measurement techniques, their time-consuming nature renders them economically unviable. Therefore, this study aims to assess the distribution of probable geogenic contamination of groundwater and develop a robust prediction model by analyzing the relationship between predictive variables and target contaminants. In this pursuit, various machine learning techniques and regression models, including Linear Regression, Random Forest, Decision Tree, K-Neighbors, and XGBoost, as well as deep learning models such as ANN, DNN, CNN, and LSTM, were employed. Elements such as aluminum (Al), boron (B), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), phosphorus (Pb), lead (Pb), and zinc (Zn) were utilized as features to predict fluoride levels. The SelectKbest feature selection method was used to improve the accuracy of the prediction model. This method identifies important features in the dataset for different values of k and increases model efficiency. The models were able to produce more accurate predictions by selecting the most important variables. The findings highlight the superior performance of the XGBoost regressor and CNN in predicting groundwater quality, with XGBoost consistently outperforming other models, exhibiting the lowest values for evaluation metrics like mean squared error (MSE), mean absolute error (MAE), and root mean squared error (RMSE) across different k values. For instance, when considering all features, XGBoost attained an MSE of 0.07, an MAE of 0.22, an RMSE of 0.27, a MAPE of 9.25%, and an NSE of 0.75. Conversely, the Decision Tree regressor consistently displayed inferior performance, with its maximum MSE reaching 0.11 (k = 5) and maximum RMSE of 0.33 (k = 5). Furthermore, feature selection analysis revealed the consistent significance of boron (B) and cadmium (Cd) across all datasets, underscoring their pivotal roles in groundwater contamination. Notably, in the machine learning framework evaluation, the XGBoost regressor excelled in modeling both the "all" and "rainy season" datasets, while the convolutional neural network (CNN) outperformed in the "dry season" dataset. This study emphasizes the potential of XGBoost regressor and CNN for accurate groundwater quality prediction and recommends their utilization, while acknowledging the limitations of the Decision Tree Regressor.

Accumulation of typical persistent organic pollutants and heavy metals in bioretention facilities: Distribution, risk assessment, and microbial community impact

Bioretention facilities have proven highly effective in removing pollutants from runoff. However, there is a concerning paucity of research on the contamination characteristics and associated risks posed by refractory pollutants in these facilities following long-term operation. This research focuses on the distribution, sources, microbial community impact, and human health risks of pollutants in eight bioretention facilities that have been operational for 5-11 years. The results showed that the distribution of Cu, Zn, and Cd was closely related to anti-seepage measures. PAHs, PCBs, and OCPs primarily accumulated in the surface, with concentrations ranging from 7.42 to 20.34 mg/kg, 31.8-77.3 μg/kg, and 60.5-163.6 μg/kg, respectively. Their concentrations inversely correlate with the depth of the media. Although the majority of contaminants remained below their respective risk thresholds, their concentrations typically exceeded those of background soil values, indicating an enrichment phenomenon. Source analysis revealed that PAHs primarily originate from oil combustion, PCBs were linked to their related industrial products, DDTs had their main sources in technical DDx and residues from the use of dicofol, while HCHs were traced back to historical residues from agricultural activities. Microbial α-diversity (Chao 1 and Shannon) decreased by 8.3-23.4% and 0.8-4.4%, respectively, in different facilities after long-term operation. The most dominant microbial phylum in the facilities was Proteobacteria (all relative abundances >48%). The total relative abundance of dominant genera was 6.7-34.3% higher than the control site, and Pseudomonas, a typical POPs-heavy metal degrading bacterium, had the highest relative abundance (>1.2%). Cu, Zn, and Cd present no non-carcinogenic risks and have low potential ecological risks. However, the lifetime cancer risk for PAHs is 10-6 ∼10-4 in most facilities and is of concern. The cancer risk for PCBs is acceptable, while OCPs pose a low cancer risk only for children.

Spatio-temporal variability of potentially toxic elements' pollution in road-deposited sediments according to health risk thresholds: a meta-analysis

Road deposited sediments (RDS) are important sinks of potentially toxic elements (PTEs), which may have a significant impact on human health. A systematic review of published papers on the PTEs occurrence in RDS was carried out. The main goal was to assess the global RDS contamination by PTEs and human health risks linked with anthropogenic activities. A systematic search was made to collect information about the most cited PTEs in the published literature and perform a statistical analysis. Subsequently, health risks were assessed for 35 different areas worldwide. PTE concentrations showed high variability, and means were multiple times higher than the corresponding consensus-based threshold effect concentrations (5.2-, 10.3-, 5.3-, 3-, 7.3-, and 3.6-fold higher for Zn, Pb, Ni, Cr, Cu, and Cd, respectively). PTEs concentrations were ranked as Zn > Pb > Cu > Mn > Cr > Ni > Cd. Non carcinogenic risks followed the trend Pb > Cu > Zn > Cd. Lead is responsible for the highest significant non carcinogenic risk to human health. Unacceptable exposition to carcinogenic risks is present in most areas. The top carcinogenic risk areas were Singapore > Beijing > Yixing > Shanghai > Zhuzhou for adult male, Dresden > Singapore > Ulsan > Huludao for adult females, and Dresden > Singapore > Ulsan > Huludao for children. Highest chromium and nickel carcinogenic risks occurred in Singapore, Cd in Dresden, and Cu in Huludao. Highest RDS contamination was seen in industrial areas due to pollutants deposition. Highest Zn, Cu, Cd, and Pb concentrations occur in densely urbanized areas due to heavy-duty vehicular exhausts.

Seasonal toxicity of urban road dust in runoff process-studies in Poland

Urban road dust (URD) is one of the most important non-point sources of pollution in agglomerations. The aim of this study was to assess the seasonal toxic effects of URD runoff in two regions of Poland. The concentrations of elements in URD and leachate were studied. The impact of pollutants in URD runoff on water organisms was evaluated using Daphtoxkit F and Rotoxkit F (LC50). The acute toxicity tests for crustaceans and rotifers were selected as the response of these taxa reflects the impact on zooplankton, a key component of aquatic ecosystem and the basis of most food webs. The concentrations of elements were found to vary depending on the site, although URD samples collected in Katowice agglomeration (Upper Silesia) had higher values of elements (Mn, Cu, Zn, As) compared to Wrocław (Lower Silesia). The concentrations of Mn, Zn, As, Cr, and Mg in water-soluble fraction of URD were higher in summer and winter in the Upper Silesia region due to rainwater runoff resulting from traffic, industries, post-industrial waste, and the presence of old heating systems. When comparing the content of elements in the water-soluble fraction between seasons, Zn, As, Cr, and Al concentrations were slightly higher in winter. The highest mortality of Daphnia magna and Brachiouns calyciflorus was observed in URD from both agglomerations in winter. However, the mortality is likely due to the concentration of elements or/and the coexistence of an unknown compound or a synergistic effect of the studied elements. This study highlights the alarming seasonal sources of elements in URD runoff, which will directly enter the food chain and affect the entire ecosystem, and human health.

Assessment of the surface water quality and primary health risk in urban wastewater and its receiving river Kathajodi, Cuttack of eastern India

Kathajodi, the principal southern distributary of the Mahanadi River, is the vital source of irrigation and domestic water use for densely populated Cuttack city which receives anthropogenic wastes abundantly. This study assesses the contamination level and primary health status of urban wastewater, and its receiving river Kathajodi based on the physicochemical quality indices employing inductively coupled plasma mass spectroscopy and aligning with guidelines from the United States Environmental Protection Agency (USEPA) and WHO. The high WQI, HPI, and HEI in the catchment area (KJ2, KJ3, and KJ4) indicate poor water quality due to the influx of domestic waste through the primary drainage system and effluents of healthcare units. A high BOD (4.33-19.66 mg L-1) in the catchment indicates high organic matter, animal waste, bacteriological contamination, and low DO, resulting in deterioration of water quality. CR values beyond limits (1.00E - 06 to 1.00E - 04) in three locations of catchment due to higher Cd, Pb, and As indicate significant carcinogenic risk, while high Mn, Cu, and Al content is responsible for several non-carcinogenic ailments and arsenic-induced physiological disorders. The elevated heavy metals Cd, Cu, Fe, Mn, Ni, and Zn, in Kathajodi, could be due to heavy coal combustion, vehicle exhaust, and industrial waste. On the other hand, Cu, Fe, K, and Al could be from agricultural practices, weathered rocks, and crustal materials. Positive significant (p ≤ 0.05) Pearson correlations between physicochemical parameters indicate their common anthropogenic origin and similar chemical characteristics. A strong correlation of PCA between elements and physiological parameters indicates their role in water quality deterioration. Assessing the surface water quality and heavy metal contents from this study will offer critical data to policymakers for monitoring and managing public health concerns.

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.

Tracing and source fingerprinting of metals from the southern coastal sediments in Bangladesh

Trace element pollution from anthropogenic sources is increasingly widespread. This pollution in terrestrial environments threatens agricultural crop production, while in aquatic environments, it threatens fish cultivation. The contamination of these crucial food sources raises significant concerns regarding food safety, security, and its potential adverse effects on human health. Coastal areas are particularly vulnerable to heavy metal pollution due to their proximity to industrial and urban centres, as well as their susceptibility to contamination from marine sources. In attempting to identify the sources of heavy metals (As, Cu, Cr, Cd, Fe, Hg, Mn, Ni, Pb, and Zn) and measure their contributions, we collected soil samples from thirty sites along the three coastal districts (Patuakhali, Barguna, and Bhola) in Bangladesh. Using atomic absorption spectroscopy, heavy metal concentrations in soil samples were measured and three receptor models (PMF, PCA-MLR, and UNMIX) were applied to detect their sources. Pairwise correlation analysis of metal concentrations in 30 sites across 3 coastal districts showed all possible patterns, including both significant and insignificant positive and negative relationships between different metals, except for As and Hg which did not display any significant relationships with other metals. The concentrations of Cu, Fe, Mn, Ni, and Zn exceed the US-EPA sediment quality standard. The applied PCA-MLR, PMF, and UNMIX models identified several sources of heavy metal contamination, including (i) mixed anthropogenic and natural activities: contribution of 59%, 37%, and 43%, and (ii) vehicle emissions: contribution of 23%, 26% and 29%. The recognized metal sources should be prioritised to avoid the discharge of poisonous pollutants from anthropogenic factors and any possible future exposure. This study's findings have implications for ongoing monitoring and management of heavy metal contamination in coastal environments to mitigate potential health and ecological impacts and can inform policy development and management strategies.

Assessment of sources and health risks of heavy metals in metropolitan household dust among preschool children: The LEAPP-HIT study

The most common construction material used in Taiwan is concrete, potentially contaminated by geologic heavy metals (HMs). Younger children spend much time indoors, increasing HM exposure risks from household dust owing to their behaviors. We evaluated arsenic (As), cadmium (Cd), and lead (Pb) concentrations in fingernails among 280 preschoolers between 2017 and 2023. We also analyzed HM concentrations, including As, Cd, Pb, chromium (Cr), nickel (Ni), copper (Cu), zinc (Zn), iron (Fe), and manganese (Mn), in 90 household dust and 50 road dust samples from a residential area where children lived between 2019 and 2021 to deepen the understanding of sources and health risks of exposure to HMs from household dust. The average As, Cd, and Pb concentrations in fingernails were 0.12 ± 0.06, 0.05 ± 0.05, and 0.95 ± 0.77 μg/g, respectively. Soil parent materials, indoor construction activities, vehicle emissions, and mixed indoor combustion were the pollution sources of HMs in household dust. Higher Cr and Pb levels in household dust may pose non-carcinogenic risks to preschoolers. Addressing indoor construction and soil parent materials sources is vital for children's health. The finding of the present survey can be used for indoor environmental management to reduce the risks of HM exposure and avoid potential adverse health effects for younger children.

Ecological risk assessment of heavy metals in urban dust in Iran: A systematic review and meta-analysis

BACKGROUND

Heavy metals in street dust are one of the most important sources of pollutants in urban areas. This urban dust can be caused by industrial activities, traffic, erosion of buildings, and fossil fuels. The aim of this systematic review is to evaluate the ecological risk of heavy metals in the dust of Iran's provinces.

METHODS

This study was conducted in February 2023 in order to investigate the environmental risks associated with heavy metals associated with dust particles in Iran. The present study was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Finally, 9 studies were extracted from the search databases.

RESULTS

The ecological risk of heavy metals in the present study was as follows: Cd (258.26؛ CI: 83.53, 433) >Pb (52.58؛ CI: 37.15, 68.02) >Cu (24.44؛ CI: 16.74, 32.14)>Ni (14.75؛ CI: 12.68, 16.82)>As (13.53؛ CI: 10.20, 16.85)>Zn (6.32؛ CI: 3.76, 8.87)>V (3.18؛ CI: 2.65, 3.72)>Cr (2.73؛ CI: 2.19, 3.27)>Co (1.94؛ CI: 1.13, 2.74). The mean ranking of the studied Pb ecological risk is as follows: Shiraz.> Tehran > Ahvaz > Ilam > Abadan > Dezful.

CONCLUSION

The ecological risk potential of Cd in Tehran was also much higher than the standard. Therefore, Tehran was the most polluted city studied in terms of the ecological risk potential of Cd (1611.41؛ CI: 1605.98, 1616.84) and Pb (86.54؛ CI: 71.46, 101.62). The average concentration as well as the ecological risk of Cr, Co, and V metals were lower than the standard. Therefore, controlling the sources of heavy metal emissions (especially lead and cadmium) is highly recommended.

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.

Accumulation degree and risk assessment of metals in street dust from a developing city in Central Taiwan

Due to the numerous industrial parks and high traffic density in Miaoli, Taiwan, large amounts of metals may be released into the atmosphere, accumulating in street dust. Therefore, this study aimed to collect street dust in Miaoli to quantify the metals and assess the accumulation degree, sources, and potential risks. The enrichment factor (EF), geological accumulation index (Igeo), ecological risk, and non-carcinogenic and lifetime carcinogenic risk were estimated to assess the accumulation degree and the potential environmental and health risks. Pearson correlation analysis, principal component analysis, and positive matrix factor model were used to clarify the relationship between levels of metals and identify possible sources. The levels of metals in street dust in order were Fe > Zn > Mn > Cu > Cr > Ni > Pb > Sr > Co > Sb. According to Igeo, the level of Ni indicated moderately polluted. The levels of Zn, Cu, and Pb showed moderate to strong pollution, strong pollution, and very strong pollution, respectively. Results of average ecological risk analysis pointed out that Pb and Cu represent a very high risk, while other metals posed low-to moderate-level ecological risks. Excluding the Steel Enterprise area, based on the EF value and source identification, it might be concluded that Co, Sr, Fe, Mn, and Sb were mainly from natural sources, while Cu, Pb, and Zn come from anthropogenic pollution sources. Based on the results of the risk assessments, most metals pose no serious adverse health risk to humans. But, in comparison to Miaoli townships, the health risks of residents living in the Steel Enterprise area were higher. However, given that children and adolescents exposure to Co, Cr, Pb, and Ni together constitute a relatively higher carcinogenic risk (CR > 10-6), more attention needs to be paid to the populations most susceptible.

Trace element contamination in soils surrounding the open-cast coal mines of eastern Raniganj basin, India

Trace element pollution of soils surrounding coal-mining areas affects the health of local communities. The increasing coal-mining and associated activities in the Raniganj basin (east India) have led to increased soil concentration of certain trace elements. To quantify the elevated trace element (TE) concentrations in the soil surrounding coal-mining areas, 83 surface soil, coal, and shale samples were collected from open-cast mining areas of the eastern Raniganj basin. The soils present are sandy silt, silty sand, and silty in nature, but almost no clay. They are acidic (pH = 4.3) to slightly alkaline (pH = 7.9) with a mean electrical conductivity (EC) of 340.45 µS/cm and a mean total organic carbon (TOC) of 1.80%. The northern and western parts of the study area were found to be highly polluted by certain metallic trace elements. The relevant environmental indices, geoaccumulation index (Igeo), contamination factors (CF), enrichment factors (EF), and pollution load index (PLI) were calculated and assessed. Analysis revealed that Cr was highly enriched in these soil samples, followed by Pb, Co, Cu, Cd, Fe, Ni, Mn, Zn, As, and Al. Geostatistical analyses (correlation coefficients and principal component analysis) indicated that the occurrence of some trace elements (Al, Cd, Co, Cu, Fe, Mn, Ni, and Zn) is most likely linked to the various coal-mining operations in the study area. However, the anomalous Cr and Pb distributions are likely influenced by other anthropogenic, mainly industrial, inputs besides coal mining. These results justify the adoption of rigorous soil monitoring programs in the vicinity of coal-mining areas, to identify pollution hotspots and to develop strategies to reduce or mitigate such environmentally damaging pollution.

Environmental hazard assessment and metal contamination in coastal sediments

In order to reduce contamination levels from diverse sources, it is important to understand the factors affecting the natural ecosystems that are impacted by coastal and marine pollution. In this study, we used GIS and remote sensing techniques to investigate and evaluate the distribution of heavy metals (Fe, Mn, Zn, Cr, Pb, Co, and Cu) in surface sediments along Tamil Nadu's East Coast (from Besant Nagar to Sathurangapattinam). The CF and Igeo of metals indicate that sediments contain no evidence of Fe, Mn, or Zn metal pollution in the sediments, with only mild contamination from Co, Cu, and Pb. In contrast, the sediment samples were found to be significantly contaminated with Cr. Heavy metal contamination occurs in the following order, according to our research: Cr > Pb > Cu > Co > Mn > Zn > Fe. Except for sites 8, 10, 11, and 13, where PLI>1 implies that there is no pollution in this area, the PLI values show that most of the locations are contaminated. The ecological risk index (ERI) values for five metals in the study areas are as follows: Cr > Pb > Cu > Mn > Zn. The sediment samples fall into the low-risk and highly polluted to dangerous sediment categories for SPI, according to the Risk index (RI). Based on the Mean Effect Range-Median Quotient (M-ERM-Q), Cu, Pb, Zn, and Cr metals in the research region have a 9-21% probability of being harmful. Statistical approaches show that the majority of heavy metals in sediments are of natural origin. The spatial distribution of heavy metals in surface sediments provides the conceptual framework for practical strategies to protect coastal areas. Many shreds of evidence indicate that anthropogenic inputs from the surrounding land area are primarily responsible for the deposition of these heavy metals in the coastal zone.

Effects of Road Dust Particle Size on Mineralogy, Chemical Bulk Content, Pollution and Health Risk Analyses

Because of the rising environmental and health concerns associated with atmospheric pollution caused by potentially toxic elements (PTEs), several road dust studies have been performed across the world in recent decades. This paper illustrates the effects of particle size on the PTE contents, mineralogical composition, environmental pollution and health risk assessments in road dust from Barcelona (Spain). The samples were sieved into five size fractions ranging from <45 to 500-800 µm. Although the major mineral contents (tectosilicates, phyllosilicates, and carbonates) were profuse in all fractions, the identified inhalable PTE particles (e.g., Fe, Cr, Cu, Zn, Ni, and REE), with size < 10 µm, were more pervasive in the finest fraction (<45 μm). This is consistent with the concentrations measured: the finest fractions were richer in PTEs than the coarser ones, resulting in a direct correlation with the enrichment factor (EFx), geo-accumulation (Igeo), and non-carcinogenic (HI) and carcinogenic (CRI) values. Igeo and EFx values can be appropriate tracers for some common elements (e.g., Zn, Sb, Sn, Cu, and Cr), but they do not seem adequate for anthropogenic particles accumulated at concentrations similar to the geogenic background. Overall, the HI and CRI values obtained in Barcelona were acceptable, reflecting no serious health impacts in the study area, except for Cr. Our results suggest that fine dust particles are a more suitable fraction to conduct pollution and health risk assessments than coarser ones, although the EFx, Igeo, HI, and CRI threshold values should be redefined in the future to include all emergent pollutants as well. In summary, monitoring programs should include at least the road dust evaluation of <45 µm particles, which can be performed with a simple sieving method, which is both time- and cost-effective.

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.

A new hazard assessment workflow to assess soil contamination from large and artisanal scale gold mining

Gold mining activities are undertaken both at large and artisanal scale, often resulting in serious 'collateral' environmental issues, including environmental pollution and hazard to human and ecosystem health. Furthermore, some of these activities are poorly regulated, which can produce long-lasting damage to the environment and local livelihoods. The aim of this study was to identify a new workflow model to discriminate anthropogenic versus geogenic enrichment in soils of gold mining regions. The Kedougou region (Senegal, West Africa) was used as a case study. Ninety-four soil samples (76 topsoils and 18 bottom soils) were collected over an area of 6,742 km2 and analysed for 53 chemical elements. Robust spatial mapping, compositional and geostatistical models were employed to evaluate sources and elemental footprint associated with geology and mining activities. Multivariate approaches highlighted anomalies in arsenic (As) and mercury (Hg) distribution in several areas. However, further interpretation with enrichment factor (EFs) and index of geoaccumulation (IGeo) emphasised high contamination levels in areas approximately coinciding with the ones where artisanal and small scale mining (ASGM) activities occur, and robust compositional contamination index (RCCI) isolated potentially harmful elements (PHE) contamination levels in very specific areas of the Kedougou mining region. The study underlined the importance of complementary approaches to identify anomalies and, more significantly, contamination by hazardous material. In particular, the analyses helped to identify discrete areas that would require to be surveyed in more detail to allow a comprehensive and thorough risk assessment, to investigate potential impacts to both human and ecosystem health.

Degradation of hexavalent chromium and naphthalene by electron beam irradiation: Degradation efficiency, mechanisms, and degradation pathway

Heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs) in industrial wastewater have attracted much attention due to their damage to the environment and the human body. Studies have shown that there may be interactions between PAHs and HMs, leading to enhanced toxicity of both pollutants. It has been shown that traditional methods are difficult to treat a combination of PAHs and HMs simultaneously. This paper presented an innovative method for treating PAHs and HMs compound pollutants by electron beam irradiation and achieved the removal of the compound pollutants using a single means. Experiments showed that the absorbed dose at 15 kGy could achieve 100% degradation of NAP and 90% reduction of Cr (Ⅵ). This article investigated the effects of electron beam removal of PAHs and HMs complex contaminants in various water environmental matrices. The experimental results showed that the degradation of NAP followed the pseudo-first-order dynamics, and the degradation of NAP was more favorable under neutral conditions. Inorganic ions and water quality had little effect on NAP degradation. For electron beam reduction of Cr (Ⅵ), alkaline conditions were more conducive to reducing Cr (Ⅵ). Especially, adding K₂S₂O₈ or HCOOH achieved 99% reduction of Cr (Ⅵ). Experiments showed that •OH achieve the degradation of NAP, and e_aq^- achieve the reduction of Cr (Ⅵ). The results showed that the degradation of NAP was mainly achieved by benzene ring opening, carboxylation and aldehyde, which proved that the degradation of NAP was mainly caused by •OH attack. The toxicity analysis results showed that the electron beam could significantly reduce the toxicity of NAP, and the toxicity of the final product was much lower than NAP, realizing the harmless treatment of NAP. The experimental results showed that electron beam irradiation has faster degradation rates and higher degradation efficiency for NAP and Cr (Ⅵ) compared to other reported treatment methods.

Comparative review of ambient air PM2.5 source apportioning studies in Tehran

Rapid urbanization and consuming lifestyles have intensified air pollution in urban areas. Air pollution in megacities has imposed severe environmental damages to human health. Proper management of the issue necessitates identification of the share of emission sources. Therefore, numerous research works have studied the apportionment of the total emissions and observed concentrations among different emissions sources. In this research, a comprehensive review is conducted to compare the source apportioning results for ambient air PM2.5 in the megacity of Tehran, the capital of Iran. One hundred seventy-seven pieces of scientific literatures, published between 2005 and 2021, were reviewed. The reviewed research are categorized according to the source apportioning methods: emission inventory (EI), source apportionment (SA), and sensitivity analysis of the concentration to the emission sources (SNA). The possible reasons for inconsistency among the results are discussed according to the scope of the studies and the implemented methods. Although 85% of the reviewed original estimates identify that mobile sources contribute to more thant 60% of Tehran air pollution, the distribution of vehicle types and modes are clearly inconsistent among the EI studies. Our review suggests that consistent results in the SA studies in different locations in central Tehran may indicate the reliability of this method for the identification of the type and share of the emission sources. In contrast, differences among the geographical and sectoral coverage of the EI studies and the disparities among the emission factors and activity data have caused significant deviations among the reviewed EI studies. Also, it is shown that the results of the SNA studies are highly dependent on the categorization type, model capabilities and EI presumptions and data input to the pollutant dispersion modelings. As a result, integrated source apportioning in which the three methods complement each other's results is necessary for consistent air pollution management in megacities.

Supplementary information

The online version contains supplementary material available at 10.1007/s40201-023-00855-0.

Short- and medium-chain chlorinated paraffins in urban road dust of Shanghai, China: concentrations, source apportionment and human exposure assessment

Chlorinated paraffins (CPs) are ubiquitous anthropogenic contaminants that have been found in various environmental media. The objective of this study was to determine concentrations, spatial distribution, possible sources and potential health risk of SCCPs and MCCPs in urban road dust collected from Shanghai, China. The concentrations ranged from 9.74 to 11,400 ng g^-1 for ΣSCCPs, 44.1 to 49,900 ng g^-1 for ΣMCCPs and 53.9 to 61,400 ng g^-1 for total CPs, respectively. MCCPs were the dominant component in all road dust, averagely accounting for 82.8% of total CPs. The concentrations of CPs in dust collected from traffic and commercial areas were significantly higher than those from campus, industrial, park and residential areas (p < 0.01), which could be attributed to tire wear in heavy traffic. All dust samples were divided into two groups by hierarchical cluster analysis for both SCCPs and MCCPs, and the most abundant homologue groups in most samples were C₁₀Cl_7-10 and C₁₃Cl_7-9 for SCCPs, and C₁₄Cl_7-9 and C₁₅Cl_8-9 for MCCPs. Correlation analysis showed that all carbon homologues in road dusts were highly correlated each other, suggesting SCCPs and MCCPs in dust maybe came from similar sources. Three sources for CPs in dust samples were apportioned by the PMF model; their relative contributions to the total CPs burden in dust were 25.6% for factor 1 (commercial CP mixture), 13.7% for factor 2 (long-distance transport) and 60.7% for factor 3 (commercial CP mixture). The median estimated daily intakes of total CPs via road dust were 1.78 × 10^-5 for children and 3.0 × 10^-6 mg kg^-1 day^-1 for adults, respectively. Quantitative risk assessment using non-cancer hazard index and total margin of exposure of total CPs indicated that total CPs at the present level in road dust pose no significant risk for both children and adults in Shanghai.

Contamination characteristics and source analysis of potentially toxic elements in dustfall-soil-crop systems near non-ferrous mining areas of Yunnan, southwestern China

Potentially toxic elements (PTEs) in the dustfall-soil-crop system pose a serious threat to the ecological environment and agricultural production. However, there is still a knowledge gap in terms of better understanding the distinctive sources of PTEs by integrating various models and technologies. In this study, we comprehensively investigated the concentrations, distribution, and sources of seven PTEs in a dustfall-soil-crop system (424 samples in total) near a typical non-ferrous mining area, using absolute principal component score/multiple linear regression (APCS/MLR) combined with X-ray diffraction (XRD) and microscopy techniques. Our results showed that the mean values of As, Cd, Cr, Cu, Ni, Pb, and Zn in the soils were 211, 14, 105, 91, 65, 232, and 325 mg/kg, respectively. These values were significantly higher than the background soil values in Yunnan. Except for Ni and Cr, all elements in the soil were significantly higher than the screening values of agricultural lands in China. The spatial distribution of PTE concentrations was similar among the three media. The ACPS/MLR, XRD, and microscopy analyses further indicated that soil PTEs mainly originated from industrial activities (37 %), vehicle emissions and agricultural activities (29 %), respectively. Dustfall PTEs mainly originated from vehicle emissions and industrial activities, accounting for 40 % and 37 %, respectively. Crop PTEs mainly originated from vehicle emissions and soil (57 %), and agricultural activities (11 %), respectively. PTEs seriously threaten the safety of agricultural products and the ecological environment once they settle from the atmosphere to soil and crop leaves, further accumulate in crops, and spread through the food chain. Therefore, our study provides scientific evidence for government regulators to control PTE pollution and reduce their environmental risks in dustfall-soil-crop systems.

Co-occurrence of polycyclic aromatic hydrocarbons and their oxygenated derivatives in indoor dust from various microenvironments in Guangzhou, China: levels, sources, and potential human health risk

For decades, the presence and potential health risk of polycyclic aromatic hydrocarbons (PAHs) in indoor dust have been extensively investigated while with limited attention to oxygenated PAHs (OPAHs). In this study, we collected 45 indoor dust from four microenvironments in Guangzhou City, China, and then focused on the co-occurrence of 16 PAHs and 8 OPAHs and their potential carcinogenic risk to humans. The ΣPAHs concentrations, dominated by 4-6 ring PAHs, ranged from 1761 to 14,290 ng/g (mean of 6058 ng/g) without significant difference in the different microenvironments (Tukey, p > 0.05). The OPAHs were observed with concentrations from 250 to 5160 ng/g (mean of 1646 ng/g), and anthraquinone (AQ) was identified as the main OPAHs with significantly high levels in the residential environment than in instrumental rooms. Notably, AQ dominated over the other target analytes in dust in this study. Our results indicated that PAHs and OPAHs in indoor dust were from outdoor environments, which mainly originated from vehicular exhaust and biomass/coal combustion. A potential cancer risk of PAHs and OPAHs to local adults and children was observed via inhalation, ingestion, and dermal absorption, with the main contribution from benzo[a]pyrene and dibenz[a,h]anthracene.

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.

Diversity of Microbial Communities, PAHs, and Metals in Road and Leaf Dust of Functional Zones of Moscow and Murmansk

The impact of geographical factors, functional zoning, and biotope type on the diversity of microbial communities and chemical components in the dust of urban ecosystems was studied. Comprehensive analyses of bacterial and fungal communities, polycyclic aromatic hydrocarbons (PAHs), and metals in road and leaf dust in three urban zones of Murmansk and Moscow with contrasting anthropogenic load were conducted. We found that the structure of bacterial communities affected the functional zoning of the city, biotope type, and geographical components. Fungal communities were instead impacted only by biotope type. Our findings revealed that the structure of fungal communities was mostly impacted by PAHs whereas bacterial communities were sensitive to metals. Bacteria of the genus Sphingomonas in road and leaf dust as indicators of the ecological state of the urban ecosystems were proposed.

Potentially Harmful Elements Associated with Dust of Mosques: Pollution Status, Sources, and Human Health Risks

Potentially harmful elements (PHEs) associated with dust generated from anthropogenic sources can be transported into mosques and deposited on the filters of the air-conditioners (AC); thereby, children and adults are exposed to such PHEs while visiting mosques. Data dealing with the assessment of PHEs pollution and its human health risk in mosques dust in Saudi Arabia are scarce. Therefore, this work aims to examine the levels and pollution status of PHEs in AC filter dust (ACFD) of mosques and their associated human health risk in three Saudi cities: Jubail, Jeddah, and Dammam metropolitan. A similar concentration pattern of PHEs is observed in three cities' mosques with noticeably higher concentrations than both global crustal and local background values for Zn, Cu, Pb, As, and Cd only. Except for Fe, Al, and Mn, the highest PHEs concentrations were found in Jeddah (1407 mg/kg), followed by Dammam (1239 mg/kg) and Jubail (1103 mg/kg). High PHEs' concentrations were also recorded in mosques located near workshops and suburban areas compared to urban areas. Based on the spatial pattern, enrichment factor, geo-accumulation index, pollution load index, and ecological risk values, Jubail, Jeddah, and Dammam have shown moderate pollution levels of Cd, As, Pb, and Zn. On the other hand, Cu. Zn, Cu, Cr, Pb, Ni, As, and Cd had degrees of enrichment levels that varied from significantly enriched to extremely highly enriched in the ACFD of the three cities. Heavy pollution is found in Jubail, which posed a higher potential ecological risk than in Jeddah and Dammam. Cd presents the highest ecological risk factors (ER) in the three cities. Carcinogenic and non-carcinogenic risks for children and adults follow the order: Jeddah > Dammam > Jubail, and the ingestion pathway was the main route for exposure. Carcinogenic and con-carcinogenic risks in the mosques of the various studied cities were generally within the acceptable range.

Analysis of spatial distribution characteristics and main influencing factors of heavy metals in road dust of Tianjin based on land use regression models

Land use regression (LUR) models are mainly used for the simulation and prediction of conventional atmospheric pollutants. Whether the LUR models can be expanded to study more toxic and hazardous pollutants (such as heavy metals) remains to be verified. Combined with the factors of road, land use type, population, pollution enterprise, meteorology, and terrain, the LUR models were used to simulate the spatial distribution characteristics of heavy metals in road dust and determine the main influencing factors. Samples of road surface dust were collected from 144 evenly distributed points in Tianjin, China, with 108 modelling points and 36 verification points. The R² values of the LUR models of Cd, Cr, Cu, Ni, and Pb contents were 0.301, 0.412, 0.399, 0.496, and 0.377, and their error rates were 2.72%, 4.96%, 4.64%, 8.91%, and 4.94%, respectively. The error rates of the kriging interpolation models were 3.33%, 6.50%, 5.14%, 18.30%, and 22.87%, which were all greater than those of the LUR models. The estimation effect of the LUR models was more refined than that of the kriging interpolation models. The contents of most heavy metals (except Ni) in road dust of the central area in Tianjin were generally higher than those of the surrounding areas. The heavy metal contents in road dust of Tianjin were mainly affected by road variables and meteorological variables. The LUR models were suitable for small-scale spatial prediction of heavy metals in urban road dust within urban areas.

Health implications, distribution and source apportionment of heavy metals in road deposited dust of Jammu City in northern India

Road deposited dust (RDD) is an important indicators of heavy metal contamination in urban areas. In this study, we measured eight heavy metals (V, Cr, Mn, Fe, Ni, Cu, Zn, and Pb) in RDD collected from 34 different locations in Jammu city represented by different land uses such as industrial, urban-residential, high-density traffic, and sub-urban locations, and evaluated their ecological and health risks. The ratio of metal concentrations in RDD to their respective background levels varied as: Cu (3.94) > Pb (3.75) > Zn (3.01) > Cr (1.75) > Ni (1.51) > Mn (1.40) > V (1.35) > Fe (1.1) suggesting Cr, Ni, Cu, Zn and Pb were enriched anthropogenically. Geospatial maps revealed a heterogeneous distribution of metals in Jammu city with metal(s) specific hotspots primarily localized around high traffic density locations and industrial clusters. The index of geoaccumulation indicated 32%, 26%, 20%, 9%, and 8%, of samples belonged to "moderately polluted" category for Zn, Cu, Pb, Cr, and Ni respectively. Health index (HI) showed low non-carcinogenic hazards of metal contamination to adults but a high hazard to children. Though the values of total carcinogenic risks (TCR) (6.53E-05 to 3.71E-04) considerably exceeded the USEPA acceptable levels (1 × 10^-6 ≤ TCR <1 × 10^-4) suggesting high carcinogenic risks of metal contamination to both adults and children. Besides potential ecological risk index (PERI) revealed that 56% of samples had PERI >40 suggesting "moderate to high ecological risk" of metal contamination in the Jammu city RDD.

Meteorological dependence, source identification, and carcinogenic risk assessment of PM2.5-bound Polycyclic Aromatic Hydrocarbons (PAHs) in high-traffic roadside, urban background, and remote suburban area

The Polycyclic Aromatic Hydrocarbons (PAHs) bound to ambient fine Particular Matter (PM2.5) are currently drawing a lot of attention due to their adverse health effects increasing lung cancer risk in humans. In this study, The PM2.5 samples were collected by high volume air samplers simultaneously from three different sites (high-traffic roadside, urban background, and remote suburban) in Tehran, Iran during warm and cold seasons (from July 2018 to March 2019), and 16 PAHs were analyzed using Gas Chromatography-Mass Spectrometry (GC-MS). Unlike previous studies, a remote suburban area was chosen so as to observe the spatial differentiation in PM2.5-bound PAH characteristics. In high-traffic roadside site, the average concentration of total PM2.5-bound PAHs (ƩPAHs) was 3.7 times the concentration value in remote suburban area. Average (ƩPAHs) ranged from 5.54 ng/m3 for remote suburban area to 20.67 ng/m3 for high-traffic roadside site. In all sites, seasonal trends of PAH concentrations elucidated high concentrations in the cold season and low concentrations in the warm season. Correlation analysis between ƩPAHs and atmospheric factors (meteorology parameters and criteria air pollutants) indicated the heterogeneous processes play an important role in the level of PAHs. The results of diagnostic ratio (DR) analysis disclosed that the dominant source of PM2.5-bound PAHs was the combustion of liquid fossil fuels. Despite the fact that incremental lifetime cancer risk (ILCR) via inhaling PM2.5-bound PAHs varied significantly in high-traffic roadside site and remote suburban site, its value was beyond the acceptable risk level in both sites. Our results suggested that effective regulations are needed to monitor PAHs concentrations and reduce PAHs emissions from liquid fossil fuel combustion so as to mitigate the potential carcinogenic risk of PAHs in ambient air.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40201-022-00821-2.

Health risk assessment and source apportionment of potentially toxic metal(loid)s in windowsill dust of a rapidly growing urban settlement, Iran

Rapid industrialization and urbanization have resulted in environmental pollution and unsustainable development of cities. The concentration of 12 potentially toxic metal(loid)s in windowsill dust samples (n = 50) were investigated from different functional areas of Qom city with the highest level of urbanization in Iran. Spatial analyses (ArcGIS 10.3) and multivariate statistics including Principal Component Analysis and Spearman correlation (using STATISTICA-V.12) were adopted to scrutinize the possible sources of pollution. The windowsill dust was very highly enriched with Sb (50 mg/kg) and Pb (1686 mg/kg). Modified degree of contamination (mC_d) and the pollution load indices (PLI_zone) indicate that windowsill dust in all functional areas was polluted in the order of industrial > commercial > residential > green space. Arsenic, Cd, Mo, Pb, Sb, Cu, and Zn were sourced from a mixture of traffic and industrial activities, while Mn in the dust mainly stemmed from mining activities. Non-carcinogenic health risk (HI) showed chronic exposure of Pb for children in the industrial zone (HI = 1.73). The estimations suggest the possible carcinogenic risk of As, Pb, and Cr in the dust. The findings of this study reveal poor environmental management of the city. Emergency plans should be developed to minimize the health risks of dust to residents.

Rare earth elements - Source and evolution in an aquatic system dominated by mine-Influenced waters

Acid mine drainage (AMD), formed by the instability of sulfides, typically generates acidity and releases potentially toxic elements and sulfate to the environment, among other pollutants. An example is the group of rare earth elements (REE) that may have high toxic behavior. This toxicity leads to degradation of soils, water reservoirs and rivers, promoting serious risks for the ecosystems. So, the main goal of the present work is to study the hydrochemical properties of a system with mine-influenced waters during the rainy season, focusing on the origin, evolution/behavior, and concentration of REE. The study area is the São Domingos mining complex, located in one of the largest metallogenetic provinces in the world (Iberian Pyrite Belt), known by the evidences of AMD contamination. The obtained results reveal extraordinarily low pH (0.4), high electrical conductivity, reaching 26,200 μS/cm, and high values of sulfate and acidity. Regarding the REE, the determined concentration exceeded that observed in normal pH of neutral freshwaters by 2-3 times the order of magnitude. The results revealed that Y and Ce are distinguished in practically all sampled sites, due to its higher concentrations, with maximum values of 221.8 and 166.9 μg/L. In general, the concentrations increase as the water pH decreases. The statistical analysis indicates that REE elements may have a common origin, mutual dependence, and similar behavior during transport with typical AMD elements and composition of host rocks. Most samples show enrichment in middle REE (MREE) (Gdn/Lun), like the classic signature of AMD. In turn, colloids and AMD-precipitates may be participating in the incorporation of these elements. Therefore, due to potential risk of impacts on ecosystems, REE are a topic of relevant interest for future studies in order to assist monitoring processes and help government decisions related to water quality management.

Determination of the Heavy Metal Bioaccumulation Patterns in Muscles of Two Species of Mullets from the Southern Caspian Sea

Simple Summary

Fish are an important source of proteins of a high biological value, of some vitamins and minerals, and of polyunsaturated omega-3 fatty acids. However, fish products can also allow harmful substances, like heavy metals, to enter the diet. Such substances are recognized as being the most serious contaminants for aquatic ecosystems at the present time. Their non-biodegradability allows them to accumulate in fish tissues, and then pass into human diets. Therefore, our study aimed to determine the concentrations of heavy metals (As, Cd, Cu, Hg, Ni, Pb, and Zn), and to evaluate the bioaccumulation patterns in the different types of musculature in two species of fish of commercial interest, Chelon auratus and Chelon saliens, from the south coast of the Caspian Sea. The results obtained emphasize the need to continue to monitor and evaluate the degree of pollution in the sampled area, both in fish and other species and also in the environment, as well as recommending prevention measures orientated towards limiting and/or reducing the excessive exposure of the human population to heavy metal contamination.

Abstract

Although fish is a food that supplies nutrients of a high biological value, they can also be a source of some harmful substances, such as heavy metals. In the same context, some human activities in the Caspian Sea have contaminated this ecosystem during the past few years. For those reasons, our objective consisted of determining the concentrations of heavy metals and evaluating their bioaccumulation patterns in the different types of musculature in two species of mullets of commercial interest, Chelon auratus and Chelon saliens, from the southern coast of this sea. For this purpose, 20 C. auratus and 29 C. saliens were caught off this coastline and the metal concentrations in 3 different muscle locations were analyzed: the ventral, dorsal and caudal muscles of each fish. The caudal muscle had higher concentrations of Cd, Cu, Pb, and Zn, whereas As, Hg and Ni accumulation seemed to be independent of the musculature type. Overall, the Cd, Hg, and Pb concentrations exceeded the maximum levels permitted in fish by the European Union. In addition, the relationships between pairs of metals were positive and elevated in all the cases, which could be a sign of heavy metal pollution in the region sampled. Therefore, it will be necessary to continue monitoring and evaluating the degree of pollution in the Caspian Sea.

Spatial distribution, pollution level, and health risk of Pb in the finer dust of residential areas: a case study of Xi'an, northwest China

The spatial distribution, pollution level, and exposure risk of Pb in the finer dust (particle size < 63 μm) of residential areas in Xi'an, northwest China were investigated in this study. Geographical information systems and geodetector methods were used to analyze the spatial variability of Pb content in the finer dust of Xi'an and its forming mechanism. The enrichment factor was used to assess the extent of Pb pollution, and the hazard index was used to evaluate the health risks to children and adults exposed to Pb. The results showed that the average content of Pb in the finer dust of residential areas in Xi'an was 99.9 mg kg^-1. In the Xi'an urban area, a higher Pb content was mainly found in the finer dust near the Second Ring Road of Xi'an City, and the Pb content in the old town of Xi'an City was relatively lower than that near the Second Ring Road. The results of geodetector analysis indicate that the spatial variability of Pb in the finer dust of the Xi'an urban area was primarily controlled by the interaction among vehicle emissions, daily behavior of residents, and industrial emissions. Pb in the finer dust from residential areas in all districts showed moderate enrichment. The non-cancer risks of Pb in the finer dust were within the safe range for both children and adults. However, the prolonged exposure risk of Pb in the finer dust of residential areas should be considered for children.

Pollution Characteristics and Human Health Risk Assessment of Heavy Metals in Street Dust from a Typical Industrial Zone in Wuhan City, Central China

This study aimed to assess the pollution levels, sources, and human health risks of heavy metals in street dust from a typical industrial district in Wuhan City, Central China. In total, 47 street dust samples were collected from the major traffic arteries and streets around Wuhan Iron and Steel (Group) Company (WISC) in Qingshan District, Wuhan. The concentrations of heavy metals (Cr, Mn, Ni, Zn, Fe, Cu, and Cd) in street dust were determined by atomic absorption spectroscopy. Results indicated that the mean concentrations of Zn (249.71 mg/kg), Cu (51.15 mg/kg), and Cd (0.86 mg/kg) in street dust were higher than their corresponding soil background values in Hubei Province. Heavy metal enrichment is closely related to urban transportation and industrial production. The pollution level of heavy metals in street dust was assessed using the geo-accumulation method (I_geo) and potential ecological risk assessment (PERI). Based on the I_geo value, Cr, Mn, Fe, and Ni showed no pollution, Zn and Cu showed light to moderate contamination, and Cd showed moderate contamination. The PERI values of heavy metals in street dust ranged between 76.70 and 7027.28, which represents a medium to high potential ecological risk. Principal component analysis showed that the sources of heavy metals in street dust were mainly influenced by anthropogenic activities. Among the studied metals, Cu, Cr, Zn, Fe, and Mn mainly come from industrial processes, while Ni and Cd come from traffic exhaust. The non-carcinogenic risk indexes of heavy metals for children and adults are ranked as Cr > Cu > Ni > Cd > Zn. The health risks to children through the different exposure pathways are higher than those for adults. Hand-to-mouth intake is the riskiest exposure pathway for non-carcinogenic risk. In addition, Cr, Ni, and Cd do not pose a carcinogenic risk for the residents.

Joint association of polycyclic aromatic hydrocarbons and heavy metal exposure with pulmonary function in children and adolescents aged 6-19 years

Studies have reported associations between polycyclic aromatic hydrocarbon (PAH) or heavy metal (HM) exposure and respiratory diseases. However, evidence of their joint associations with pulmonary function, especially in children and adolescents aged 6-19 years, is lacking. We utilized cross-sectional data from 1,734 children and adolescents aged 6-19 years collected in the National Health and Nutrition Examination Survey 2007-2012 and analysed mixed PAH and mixed HM exposures and their joint association with pulmonary function by applying weighted quantile sum (WQS) regression and Bayesian kernel machine regression (BKMR). Multivariate linear regressions were carried out to determine the relationships between individual urinary PAH metabolites or blood HM levels and pulmonary function indices. We found that mixed PAHs and HMs were negatively related to forced expiratory volume in 1 s (FEV1) in subjects aged 6-12 years (all p values < 0.05). We found synergistic associations of PAH and HM exposure on pulmonary function impairment, mainly in children; lead (Pb) was the most damaging. In the analysis of individual PAH metabolites or HMs, Pb exposure was negatively associated with FEV1 values in all subgroups (all p values < 0.05). Thus, our findings indicate that increased PAH or HM exposure is associated with impairments to pulmonary function and that this association is more pronounced in children.

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.

Decrypting the synergistic action of the Fenton process and biochar addition for sustainable remediation of real technogenic soil from PAHs and heavy metals

The objective of this study was to demonstrate the feasibility and the relevance of combining biochar with the Fenton process for the simultaneous improvement of polycyclic aromatic hydrocarbons (PAHs) degradation and immobilization of heavy metals (HMs) in real soil remediation processes at circumneutral pH. The evaluation of PAHs degradation results was performed through multivariate statistical tools, including principal component analysis (PCA) and partial least squares (PLS). PCA showed that the level of biochar amendment decisively affected the degree of degradation of total PAHs, highlighting the role of biochar in catalyzing the Fenton reaction. Moreover, the PLS model was used to interpret the important features of each PAH's physico-chemical properties and its correlation to degradation efficiency. The electron affinity of PAHs correlated positively with the degradation efficiency only if the level of biochar amendment sat at 5%, explained by the ability of biochar to transfer the electrons to PAHs, improving the Fenton-like degradation. Moreover, the addition of biochar reduced the mobilization of HMs by their fixation on their surface, reducing the Fenton-induced metal leaching from the destruction of metal-organic complexes. In overall, these results on the high immobilization rate of HMs accompanied with additional moderate PAHs degradation highlighted the advantages of using a biochar-assisted Fenton-like reaction for sustainable remediation of technogenic soil.

Assessment of total concentrations of heavy metals in industrial sludges from the North of Vietnam and their potential impact on the ecosystem

Industrial sludges from wastewater treatment plants of industrial parks and a drinking water treatment plant in northern Vietnam were investigated in this study. The total concentrations of heavy metals (As, Cd, Cu, Cr, Ni, Hg, Pb, Zn) and other elements (Mn, Pd, Sb, V) in the sludges were measured using the ICP-MS method. In addition, the surface characteristics of the samples were analyzed using SEM-EDS and FTIR techniques. According to Vietnam's current waste management regulation, the investigated industrial sludges belonged to the hazardous waste category (with Pb concentration > 300 µg/g). In contrast, the sludge from the drinking water treatment plant had a low content of heavy metals and toxic elements. The sequential extraction method revealed that the heavy metals in the industrial sludges exhibited higher mobilization forms (exchangeable and reduceable fractions) than those in the drinking water sludges. The mobilization ability of heavy metals is probably related to the surface function groups of the sludges, which were dominated by (-COOH) and (-OH) groups. The potential ecological risk assessment calculations indicated that the industrial sludges had high potential risk (with the RI values ranging from 229.7 to 605.4), mainly due to the content of Cd in the sludge samples. Further studies about the fate and transport of Cd and other toxic metals in the sludges are highly recommended to better understand their risk to the surrounding environment, such as groundwater and agricultural soil.

Traffic emission dominates the spatial variations of metal contamination and ecological-health risks in urban park soil

Metals in urban park soil are closely related to traffic emissions, which adversely affect soil quality and human health. However, little is known about the quantitative impacts of traffic on the spatial variations of metals in park soil after the banning of leaded gasoline. Herein, concentrations of Cu, Pb and Zn in surface soil of four recreational parks of Sydney (Ashfield, Robson, Lamberts and Leichhardt) were measured to evaluate their spatial characteristics in contamination, ecological and health risks and relationships with traffic emissions. Contamination of metals are assessed by contamination factor (CF). Normalized metal concentrations (<63 μm) in the park soil were 24-614, 23-3520 and 99-3060 mg kg^-1 for Cu, Pb and Zn, respectively, and CFs ranged from 1.4 to 207, whose variations inter- and intra-parks were related to traffic volumes. Traffic emission accounted for 72-84% of metals contamination in soil of Ashfield, Robson and Lamberts by sites, whereas the values were 25-70% for Leichhardt due to the absence of a surrounding arterial road. In Ashfield and Robson Parks, metal concentrations from traffic decreased exponentially with distance from arterial roads. Metals in Lamberts Park and in areas near arterial roads in Ashfield and Robson Parks may raise ecological risk, and traffic sources contributed to 61-81% of the risk. The ranges of ecological risk zones away from arterial roads and average daily traffic volumes showed an exponential relationship. Copper and Zn in soil of the four parks have no non-carcinogenic health risk for children and adults, and Pb has negligible health risk for adults. Lead in Lamberts Park and in sites near arterial roads of Ashfield and Robson Parks may raise non-carcinogenic risk for children (HI > 1) due to traffic emissions. These results emphasize the remarkable influence of traffic emissions on urban soil metal, which can be predicated quantitatively by traffic volume.

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.

A case study on the occurrence of polycyclic aromatic hydrocarbons in indoor dust of Serbian households: Distribution, source apportionment and health risk assessment

This study was conducted in order to obtain the first insight into the occurrence, potential sources, and health risks of polycyclic aromatic hydrocarbons (PAHs) in indoor dust. Samples (n = 47) were collected from households in four settlements in the northern Serbian province of Vojvodina. Total concentrations of 16 EPA priority PAHs in the dust samples varied from 140 to 8265 μg kg^-1. Mean and median values for all samples were 1825 and 1404 μg kg^-1, respectively. According to the international guidelines for indoor environment, PAH content can be regarded as normal (<500 μg kg^-1) for ∼6% of the samples, high (500-5000 μg kg^-1) for ∼87% of the samples, and very high (5000-50000 μg kg¹) for ∼6% of the samples. In all settlements, PAHs with 4 rings were the most prevalent (accounting for 40-53% of the total PAHs). They were followed by 3-ringed PAHs (29-40%), which indicates rather uniform PAH profiles in the analyzed dust. Based on diagnostic ratios, principal component analysis (PCA), and positive matrix factorization (PMF), pyrogenic sources, such as vehicle emissions and wood combustion were the dominant sources of PAHs in analyzed samples. Health risk assessment, which included incidental ingesting, inhaling and skin contact with PAHs in the analyzed dust, was evaluated by using the incremental lifetime cancer risk (ILCR) model. Median total ILCR was 3.88E-04 for children, and 3.73E-04 for adults. Results revealed that major contribution to quite high total ILCRs was brought by dermal contact and ingestion. Total cancer risk for indoor dust indicated that 85% of the studied locations exceeded 10-4. This implies risk of high concern, with potential adverse health effects. The results are valuable for future observation of PAHs in indoor environment. They are also useful for regional authorities who can use them to create policies which control sources of pollution.