Spatial distribution of pollution characteristics and human health risk assessment of exposure to heavy elements in road dust from different functional areas of Zhengzhou, China

Comprehensive analysis and risk assessment of fine road dust in Abbottabad city (Pakistan) with heavy traffic for potentially toxic elements

Human activities have far-reaching impact on natural ecosystems, causing increasing disturbances and disruptions to the delicate balance of the environment. Poor land use planning, urbanization, infrastructure development, and unplanned tourism exacerbate contamination and degradation in tourist destinations, yet the pollution of potentially toxic elements (PTEs) in these environments remains inadequately explored. To address this issue, we investigated the concentrations of acid-digested PTEs in road dust in Abbottabad city (Pakistan) with heavy traffic. The current study also evaluated PTE associated pollution, ecological and health risks, and potential sources of these elements. The average concentrations (in mg kg-1) of PTEs in road dust were highest for Fe (15540), followed by Mn (304), Zn (139), Cu (50.0), Pb (21.5), Cr (13.0), Ni (10.3), Co (6.66), and Cd (0.236). The levels of Co, Cr, Mn, Ni, and Fe were below the upper continental crust (UCC) averages, while Cd, Cu, Pb, and Zn exceeded them. Spatially, Cd, Cu, Pb, and Zn were found at higher levels near traffic hotspots, bus stands and automobile workshops. Road dust in Abbottabad exhibited unpolluted to moderate pollution levels (geo-accumulation index), with Cd, Cu, Zn, and Pb at 23 % of the sites. The enrichment factor results indicated a significant anthropogenic influence, with Cd being significantly enriched and Zn, Cu, and Pb moderately enriched. The contamination factor results revealed moderate contamination by (Cd: 2.62, Zn: 2.08, Cu: 1.79, Pb: 1.27). Single metal risk index showed that 61 % of the sites posed considerable to very high ecological risks due to Cd, which was highlighted as a significant concern. The absolute principal component scores-multiple linear regression model identified three factors contributing to PTE pollution: lithogenic (Co, Fe, Mn, Ni), traffic-related (Cd, Cu, Pb, Zn), and mixed sources (Cr), with contributions of 52.8 %, 35.8 %, and 11.4 %, respectively. The PTE hazard quotient and total hazard index values for children and adults were below the safe risk level of 1, indicating no non-carcinogenic health risks. The cumulative carcinogenic risk values to the residents were also within acceptable limits. However, children's susceptibility to non-carcinogenic risks is higher due to their behavior and lower body weight. This study highlights the accumulation of PTEs in Abbottabad's environment, which poses challenges to long-term sustainability, particularly amid unplanned tourism. Therefore, urgent measures are necessary to mitigate PTE pollution and preserve tourist spots and public health.

Determination of priority control factors for risk management of heavy metal(loid)s in park dust in Mianyang City

In order to determine the priority control elements and sources of heavy metal(loid)s (HMs) pollution in park dust, this study collected dust samples from 25 parks in the urban area of Mianyang City and measured the contents of 10 HMs. Based on Monte Carlo simulation, the probabilistic pollution levels and ecological-health risks of HMs were assessed. We found that the average contents of Zn, Co, Pb, and Cr were much higher than their background values in local soil and were influenced by artificial activities. The pollution assessment found that 5 parks were moderately polluted. The comprehensive pollution of HMs in the dust was mainly caused by Zn and Cr, and industrial source was the main contributor to Zn and Cr pollution. The contribution of As, Co, and Pb to the comprehensive ecological risk was high, accounting for 54.6%. Co, Pb, and As were the priority control HMs of ecological risk, while mixed source and industrial source were the priority control sources. HMs presented potential carcinogenic health risks to both children and adults. The non-carcinogenic risk to adults was within safety level, while some parks showed non-carcinogenic risk to children, which should be paid attention to. The source-specific health risk assessment showed that Cr and As were the priority control HMs for human health, while mixed source and industrial source were the priority control sources.

Spatial distribution characteristics and source apportionment of heavy metal(loid)s in park dust in the Mianyang urban area, China

Park dust is a carrier of heavy metal pollutants and could potentially harm the health of urban residents. The concentrations of 10 heavy metal(loid)s (HMs) in park dust from the Mianyang urban area were analysed via X-ray fluorescence spectrometry. Based on ArcGIS spatial analysis, Spearman correlation analysis, spatial autocorrelation analysis, and the positive matrix factorization (PMF) model, the spatial distribution and sources of HMs in park dust were studied. The average contents of Zn, Co, Cu, Cr, Pb, and Ba in park dust were 185.0, 33.7, 38.7, 178.7, 51.0, and 662.1 mg/kg, respectively, which are higher than the reference values. The 10 HMs exhibited obvious spatial distribution and local spatial agglomeration patterns. High concentrations of As and Pb were primarily concentrated in the eastern part of the Mianyang urban area. High concentrations of Zn, Cr, and Cu were largely distributed in parks near the Changjiang River and Fujiang River. A high concentration of Co was concentrated in the northern region. The high-value areas of Mn, Ba, V, and Ni occurred far from the city centre and were located in the southwestern region. We found that Pb and As primarily originated from mixed traffic and natural sources; Zn, Cr, and Cu mainly originated from industrial activities; Co largely originated from building sources; and Ba, Ni, Mn, and V were mostly derived from natural sources. Mixed, industrial, building, and natural sources accounted for 24.5%, 24.8%, 24.7%, and 26.0%, respectively, of the HM sources. Co, Cu, Cr, and Zn in the Mianyang urban area were obviously influenced by human activities and should receive close attention.

Response of trace elements in urban deposition to emissions in a northwestern river valley type city: 2010-2021

Anthropogenic activities release significant quantities of trace elements into the atmosphere, which can infiltrate ecosystems through both wet and dry deposition, resulting in ecological harm. Although the current study focuses on the emission inventory and deposition of trace elements, their complex interactions remain insufficiently explored. In this study, we employ emission inventories and deposition data for eight TEs (Cr, Mn, Ni, Cu, Zn, As, Cd, Pb) in Lanzhou City to unveil the relationship between these two aspects. Emissions in Lanzhou can be roughly divided into two periods centered around 2017. Preceding 2017, industrial production constituted the primary source of TEs emissions except for As; coal combustion was the primary contributor to Cr, Mn, and As emissions; waste incineration played a significant role in As, Zn, and Cd emissions; biomass combustion influenced Cr and Cd emissions; and transportation sources were the predominant contributors to Pb and Cu emissions. With the establishment of waste-to-energy plants and the implementation of ultra-low emission retrofits, emissions from these sources decreased substantially after 2017. Consequently, emissions from industrial production emerged as the main source of TEs. The deposition concentrations of Cr, Mn, Ni, Cu, and Pb followed a similar trend to the emissions. However, Cd and As exhibited lower emissions and a less pronounced response relationship. Moreover, Zn concentrations fluctuated within a narrow range and showed a weaker response to emissions. The consistent changes in emissions and TEs deposition concentrations signify a shift in deposition pollution in Lanzhou city from Coal-fired pollution to that driven by transportation and industrial activities. Within this transition, the industrial production process offers significant potential for emission reduction. This insight provides a crucial foundation for managing TEs pollution and implementing strategies to prevent ecological risks.

Elemental distribution and source analysis of atmospheric aerosols from Meycauayan, Bulacan, Philippines

One of the industrialized cities in the Philippines is Meycauayan, Bulacan. This study reports the elemental distribution and source apportionment in eight varying land cover-land use type sampling points located along the Marilao-Meycauayan- Obando Rivers System. Elemental analysis was conducted using a scanning electron microscope coupled with energy dispersive x-ray. Cu, Pb, Zn, Cr, Mn, As, Cd, Co, Fe, Ni, Ti, and V concentrations were determined using Inductively Coupled Plasma Mass Spectrometry, and Hg concentrations by Mercury analyzer. Principal component analysis (PCA), hierarchical cluster analysis (HCA), and Pearson's r correlation were used to analyze different sources of heavy metals and its corresponding land use-land cover type. The aerosol samples showed the presence of heavy metals Pb and Hg, elements that were also detected in trace amounts in the water measurements. Concentrations of heavy metals such as Cu, Fe, Pb, Zn, V, Ni, and As found in the atmospheric aerosols and urban dusts were attributed to anthropogenic sources such as residential, commercial and industrial wastes. Other source of aerosols in the area were traffic and crustal emissions in Meycauayan. Using HCA, there are 3 clusters observed based on the similar sets of heavy metals: (1) AQS1 (Caingin), AQS2 (Banga), and AQS8 (Malhacan); (2) AQS3(Calvario), AQS4 (Camalig), and AQS5(Langka); (3) AQS1(Sto Nino-Perez), and (AQS7) (Sterling). These groups are related based on different land use setting such as residential/commercial, agricultural, and commercial/industrial areas. Our study recommends the need to address heavy metal pollution in Meycauayan in support to the ongoing implementation of laws and regulations by the local and private sectors.

A magnetic solid phase extraction procedure for Pb(II) at trace levels on magnetic Luffa@TiO2 in food and water samples

A novel magnetic Luffa@TiO₂ sorbent was synthesized and characterized by using XRD, FTIR and SEM techniques. Magnetic Luffa@TiO₂ was used for solid phase extraction of Pb(II) in food and water samples prior to its flame atomic absorption spectrometric (FAAS) detection. The analytical parameters such as pH, adsorbent quantity, type and volume of eluent, and foreign ions were optimized. Analytical features such as the limit of detection (LOD) and the limit of quantification (LOQ) of Pb(II) are 0.04 μg L^-1 and 0.13 μg L^-1 for liquid samples and 0.159 ng/g and 0.529 ng/g for solid samples, respectively. The preconcentration factor (PF) and relative standard deviation (RSD%) were found 50, and 4 % respectively. The method was validated by using three certified reference materials (NIST SRM 1577b bovine liver, TMDA-53.3 and TMDA-64.3fortified water). The presented method was applied to lead contents of some food and natural water samples.

Identifying proxies and mapping heavy metals concentrations in city road dusts: A case study in the Brussels-Capital Region, Belgium

This paper investigates the spatial distribution of heavy metals (HMs) concentrations in road dusts over a part of the Brussels-Capital Region (BCR), with the aim of identifying the most relevant factors impacting these concentrations and subsequently mapping them over all road segments. For this goal, a set of 128 samples of road dusts was collected over a three years time span in the Anderlecht municipality, that covers about a tenth of the BCR area. The concentrations of Cd, Cr, Cu, Ni, Pb and Zn have been measured in the finest fraction ( ⌀ < 250 μm) using ICP-OES. In parallel, continuous and categorical-valued proxies have been collected over all road segments. Using a multivariate linear modeling (MLR) approach, the most influential proxies that have been identified are the distance to the center of the BCR, land use, road hierarchy and roadside parking occupation. The performance of the MLR models remains however limited, with adjusted R 2 values around 0.5 for all HMs. From a spatial analysis of the regression residuals, it is likely that some useful proxies could have been overlooked. Although these models have clear limitations for reliably predicting HMs concentrations at specific locations, the corresponding maps drawn over all road segments provide a useful overview and help designing sound monitoring policies as well appropriate implementation of mitigation measures at places where road dust pollutants tend to concentrate. Further studies are needed to confirm this, but it is expected that our models will perform reasonably well over a large part of the BCR. It is believed too that our findings are relevant for modeling road dusts pollution in other cities as well.

Heavy metal levels in the soil near typical coal-fired power plants: partition source apportionment and associated health risks based on PMF and HHRA

In this study, five priority metals recommended by the Ministry of Ecology and Environment of China (MEEC) were investigated. In the Bijie region of Guizhou Province, three typical coal-fired power plants were chosen as the research locations. A combination of 24 soil samples was obtained at various distances and depths from the point source of contamination. The authors found that the average contents of As, Cd, Cr, Ni, and Pb were 14.15, 1.52, 16.80, 40.71, and 53.00 mg kg^-1, respectively, with Cd and Pb pollution prominent. In another, soil heavy metal (SHM) content tends to increase or decrease dependently with the increase of sampling distance and depth, with total concentrations ranging from 77.14 to 157.33 mg kg^-1. Combining PCA and PMF models, the number of source factors was determined more clearly and accurately using PCA, and the Q-value of PMF was used for validation. The PCA-PMF indicated that the primary anthropogenic sources were transportation-related activities and emissions from coal combustion. The health risks of SHMs under three different exposure routes were then assessed using the HHRA. The findings showed the five HMs in order of non-carcinogenic risk were As > Pb > Cr > Ni > Cd. The comprehensive non-carcinogenic risk for children under the oral intake route around plant B and C was greater than 1, pointing to a potential health risk to children from the soils. The carcinogenic risk of HM was less than 1.00E-04 for both single-factor and multifactor under all three exposure routes, which is below the tolerable limit.

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.

Geochemistry of street dust in Tyumen, Russia: influence of traffic load

This study investigates the elemental composition, organic carbon content, pH values, and particle size characteristics in 50 road dust samples collected from Tyumen, a large city in Western Siberia (Russia). The content of 62 major and trace elements was studied using atomic emission spectrometry (ICP-AES) и inductively coupled plasma spectrometry (ICP-MS). It was revealed that the dust has an alkaline reaction pH = 7.4-10.2 and low organic carbon content (0.07-2.9%). The grain size distribution of the road dust samples revealed that the predominant grain size fraction was of 100-250 μm. The content of small particles (PM₂ and PM₁₀) representing the greatest environmental hazard is minimal on roads with an average traffic intensity. Studies have shown that the main road dust pollutants in Tyumen are Ni, Sb, Cr, Zn, and Co. The average geoaccumulation index (Igeo) values are ranked as Ni (2.2) > Sb (1.5) > Cr (1.3) > Zn (0.4) > Co (0.4) > Cu (0.2). The contamination evaluation through enrichment factor (EF) calculation showed that road dust is highly enriched in Ni and significantly in Cr and Sb. More than 80% of Zn, Co, and Cu and more than 90% of Ni, Sb, and Cr come from anthropogenic sources. The average concentration of Ni and Cr in the road dust of Tyumen is one order of magnitude higher than in other cities of the Earth where similar studies were carried out. The high Ni content is associated with the composition of local soils and roadways, increased content in vehicle exhaust gasses, and abrasion of metal parts. Calculations of the total enrichment index Ze showed that the level of road dust pollution in most of Tyumen's territory is hazardous.

Incorporating in vitro bioaccessibility into human health risk assessment of heavy metals and metalloid (As) in soil and pak choi (Brassica chinensis L.) from greenhouse vegetable production fields in a megacity in Northwest China

The rapid development of greenhouse vegetable production (GVP) in densely populated areas may cause the heavy metal/metalloid accumulation in soil and pose a threat to human health. In this study, 180 pairs of topsoil and pak choi (Brassica chinensis L.) samples were collected from GVP fields in Xi'an city in Northwest China to analyze health risks of Cd, Cr, Pb, and As in soil and pak choi combining in vitro bioaccessibility investigation. The results showed that Cd and Cr were common pollutants in both soil and pak choi. In the soil-pak choi system, the indexes of non-carcinogenic and carcinogenic risk for adults and children were 1.53, 2.68, and 1.37 × 10^-4, 8.14 × 10^-5, respectively, thereby indicating the presence of heavy metal/metalloid health risks for both groups. Based on the results, procedures to mitigate heavy metal/metalloid contamination risks should be discussed more during the development of GVP in the largest city in Northwest China.

Source, degree and potential health risk of metal(loid)s contamination on the water and soil in the Söke Basin, Western Anatolia, Turkey

Water and soil quality are the two most important parameters for sustainable agriculture and regional development in the basin. This study focused on the causes of soil and water contamination and the potential impact of drinking water on community health. Reasons for metal(loid)s enrichment in the water and soil in the Söke Basin were examined by considering anthropogenic and geogenic inputs. Four rock samples in the drainage network, 28 soil samples, and 29 water samples in the Söke Plain were collected. All samples were analyzed for metal(loid)s by inductively coupled plasma-mass spectrometry (ICP-MS). The carcinogenic and non-carcinogenic effects of water on human health were calculated mathematically. Potential ecological risk index (PERI), enrichment factor (EF), and ecological risk (ER) were calculated for the soil samples. In addition, principal component analysis (PCA) with Varimax rotation and Kaiser normalization was applied to the soil data set. Cr, Ni, and Cd contamination in soils was associated with anthropogenic inputs, while arsenic contamination was related to both anthropogenic and geogenic inputs. As, B, Ba, Pb, and Sb contamination was found in some drinking water. As contamination has been clearly found to be caused by natural geological processes in and around Lake Azap. It was determined that metal(loid)s enrichment occurred in drinking water due to the mixing of geothermal waters affected by seawater intrusion with surface and groundwater. Contamination inputs were geogenic, but their negative impacts appearing in surface water and drinking water occurred due to human influence.

Pollution characteristics, spatial distribution, and source identification of heavy metals in road dust in a central eastern city in China: a comprehensive survey

Road dust enriched with heavy metals (HMs) is detrimental to ecosystems and human health in urban environments. In this study, it is to explore the concentrations, spatial distribution, contaminated levels, and source identification of six HMs (lead (Pb), zinc (Zn), copper (Cu), cobalt (Co), chromium (Cr), and nickel (Ni)) based on 130 road dusts in Xinyang urban area. The results indicated that the contents of Pb, Zn, Cu, and Co were higher than the background values in more than 99% of the samples, and their average concentrations were 15.2, 9.2, 8.6, and 6.3 times the background value, respectively. The spatial distribution of high-value areas for Pb, Zn, Cu, Cr, and Ni was more similar, which was associated with traffic density near major roads and population and settlement patterns. Co was relatively different from the five elements, which was distributed in the areas of residence, commerce, and industry. Furthermore, the investigated HMs were clearly polluted, with Pb, Zn, Cu, and Co indicating high levels of contamination, while Cr and Ni were moderately polluted. The comprehensive pollution of the six HMs was mostly moderate to heavy in this study. Moreover, three sources of HMs designated by correlation analysis (CA) and principal component analysis (PCA) were mixed traffic emissions and industrial waste for Cu and Cr; automotive emissions for Pb, Ni, and Zn; and mixed domestic waste and industrial activities for Co, with contributions of 42.3%, 46.4%, and 11.3% via the principal component analysis-multiple linear regression (PCA-MLR) model. The multi-factor index for pollution assessment combined with source identification is extremely effective and practical for providing reliable data support and a theoretical reference for pollution monitoring and governance.

Quantification of Pb pollution sources in complex urban environments through a multi-source isotope mixing model based on Pb isotopes in lichens and road sediment

Despite a growing focus on anthropogenic toxic metal pollution in urban environments, few studies have addressed the problem of quantification when more than two pollution sources are likely present, particularly within complex urban settings in the United States (U.S.). In this study, we utilize the MixSIAR package in R for source apportionment based on Pb isotopic signatures in lichen and road sediment in two urban-industrial centers in SW Ohio (OH). We show that ranges of pollutant contributions are more useful than only visualizing mean or raw values of source apportionment, because this avoids overinterpretation of data when certain sources have a large range of uncertainty. We point out both the dominance of industrial pollution as well as the legacy of leaded gasoline pollution in typical mid-sized U.S. cities, which is evident in both road sediment and lichens. Leaded gasoline contribution to Pb in Middletown, OH lichens mostly vary between ~10 and 25%, while in Hamilton, OH the contribution to lichens and road sediment tends to be relatively negligible except for two road sediment samples and one lichen sample, where median contributions are ~20-30%. Industrial combustion pollution source contributions vary between ~25 and 75% in Hamilton, and ~50-100% in Middletown, OH. Furthermore, comparing pollution sources in lichens to modern particulate matter can provide a record of how pollutant sources change over time, such as our traffic lichen (Sample Li-9) plotting closer to leaded gasoline on a bivariate mixing diagram than modern traffic particulate matter, or our coke plant lichen containing slightly less Pb contribution from industrial combustion sources relative to modern coke plant particulate matter. Lastly, when applicable, multi-source mixing models should be complimented in future studies with additional isotopic source tracers such as Cu, Zn, Nd, and Os to further elucidate unique sources of metal pollutants in addition to Pb.

Analyzing environmental risk, source and spatial distribution of potentially toxic elements in dust of residential area in Xi'an urban area, China

A comprehensive study on concentration, spatial distribution, pollution, ecological-health risk and source of potentially toxic elements (PTEs) in dust of residential area in Xi'an, China were conducted to explore the environmental quality of residential area in urban district. The results show that the concentrations of V, Ni, and Mn in the dust were less than, while the contents of Cr, Zn, Pb, Cu, and Ba in the dust were obviously larger than, the soil background values of Shaanxi. The high-value area of PTEs primarily concentrated in densely populated areas, heavily trafficked areas and the surroundings of plants. Cr, Pb and Zn posed moderate enrichment and Pb possessed moderate ecological risk in the dust. The comprehensive pollution levels of PTEs in the dust were uncontaminated to moderately contaminated and their comprehensive ecological risk were moderate. The non-carcinogenic risks of the PTEs for adults and children were in the safe level and the carcinogenic risks of Ni and Cr were under the current acceptable value. Four major sources were discriminated on basis of the multivariate statistical analysis results and the content characteristics, enrichment degrees, and the spatial distribution features of the PTEs, viz. Mn, V, and Ni primarily came from natural source; Pb, Zn, and Cu mainly originated from traffic source; and Ba and Cr were respectively from construction source and coal-fired power plant source, which respectively contributed 22.8%, 28.3%, 47.3%, and 1.6% to the total content of PTEs determined in the dust.