Level and contamination assessment of environmentally sensitive elements in smaller than 100 μm street dust particles from Xining, China

Particle size distribution and total suspended solid concentrations in urban surface runoff

An in-depth understanding of particle size distribution as well as total suspended solids (TSS) in surface runoff is essential for managing urban diffuse pollution. In this study, field experiments and model simulation were undertaken to explore and confirm the dynamic runoff behaviour of TSS and their influencing factors. Field observation results showed that samples with high TSS concentrations contained coarser particles (>100 μm) during three natural rainfall events. Particle size distribution as well as road-deposited sediments (RDS) amount before and after these rainfall events also confirmed that a higher percentage of washed-off coarser particles resulted in higher TSS concentrations in surface runoff water. The impacts of rainfall characteristics, urban-rural gradients, surface roughness, and climate difference on particle distribution as well as TSS concentration were analyzed using the wash-off formula of particle size. These factors mainly affected the contribution rate of RDS to TSS by altering particle size composition; rates ranged from 4% to 44% under different rainfall characteristics. The critical particle size (<100 μm) was developed according to the mass percentage of particles with different sizes in RDS and TSS. Our results can provide a simple and effective way of assessing RDS contribution to TSS in surface runoff.

Spatial distribution, risk estimation and source apportionment of potentially toxic metal(loid)s in resuspended megacity street dust

The levels of potentially toxic metal(loid)s (PTMs) As, Cu, Co, Cr, Hg, Mn, Ni, Pb, and Zn in resuspended street dust (<100 μm particles) from a megacity in north China were determined. The sources of PTMs in resuspended street dust were analyzed using multivariate statistical analysis and positive matrix factorization methods that combined the spatial distributions of PTMs. Average levels of Zn, As, Pb, Cu, Co, and Hg exceeded those found in local soil samples, while those of Cr, Mn, and Ni were less than their background levels found in local soil. The overall contamination of PTMs in resuspended street dust was characterized as moderately contaminated and as uncontaminated to moderately contaminated. The ecological risk associated with Hg was very high, while the ecological risks associated with Cu, Co, Cr, Mn, Ni, Pb, and Zn were low. The overall ecological risk of PTMs was defined as high, driven by Hg. The non-carcinogenic risks of PTMs to inhabitants fell within safety limits, and the carcinogenic risks of As, Co, Cr, and Ni were below receivable values. A comprehensive analysis of PTMs sources revealed that Co, Zn, Cu, and Pb were principally associated with traffic emissions, which accounted for about 38.3% of these PTMs' contents. Mn, Ni, and Cr were mainly generated by natural source, which contributed to about 41.5% of these PTMs' concentrations. Hg and As were primarily derived from coal-related industrial source, which accounted for 77.9% of Hg and 62.9% of As in resuspended street dust. This study demonstrates that coal-related industrial discharges and traffic emissions are the main anthropogenic sources of PTMs contamination in resuspended street dust in the study area.

Productivity and heavy metal pollution management in a silage maize field with reduced recycled wastewater applications with different irrigation methods

Using wastewaters in irrigated agriculture can cause heavy metal accumulation as well as salinity in soil. A practical way of minimizing accumulation in soil is to use irrigation techniques that require less water and consequently introduce less heavy metals into the feeding chain in silage maize cultivation with wastewater irrigation. The objective of this study is to address this issue. A factorial field experiment was carried out for two years in a completely randomized design with three replicates. Experimental plots were irrigated with three different irrigation methods (subsurface and surface drip, and furrow) applying three different levels (full irrigation and 33 and 67% deficit irrigations) of recycled wastewater and freshwater. The results showed that soil heavy metal contents, salinity, macro nutrients, organic matter, cation exchange capacity, porosity and wet aggregate stability were significantly higher in full irrigation with wastewater, while pH, carbonates, bulk and particle densities were significantly lower. Drip methods reduced salinity and heavy metal contents significantly. Heavy metal pollution indexes also indicated that drip methods are more effective in reducing metal pollution in soil. However, considerable accumulations of Cd and Ni were found with all methods while deficit irrigation decreased accumulations. The highest cation exchange capacity and K₂O contents and the lowest exchangeable sodium percentage were determined with the subsurface drip method. The subsurface drip method saved 20.7 and 49% more irrigation water than the surface drip and furrow methods under fully irrigated conditions. Therefore, it can be concluded that using the subsurface drip method with recycled wastewater can be used in silage maize cultivation because soil productivity and water savings increased while metal pollution and salinity in soil decreased. Moreover, using 33% less wastewater can be a useful practice to decrease Cd and Ni accumulation.

Environmental and human health risks associated with exposure to hazardous elements present in urban dust from Barranquilla, Colombian Caribbean

Urban dust is a mixture of deposited particles from different sources usually linked to potentially toxic elements (PTEs). Despite the industrialization of many South American countries, little is known about the impact of particulate matter in large cities; these data are necessary to promote environmental policies aiming to protect human health. The main objective of this work was to evaluate the particle size distribution, composition, and environmental and human health risks of settled dust particles from Barranquilla, a Colombian Caribbean industrialized area. Trace elements were analyzed by inductively coupled plasma-mass spectrometry from 35 different sites, covering all city areas. Dust was mostly composed of 10-to-70-μm particles. The average concentrations of V, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Mo, Ag, Cd, Sn, Sb, Pb, and Bi were above background. High spatial heterogeneity was observed for Cu, Zn, As, Se, Mo, Ag, Sn, Sb, and Bi. Concentration factors suggest that urban dusts are extremely contaminated by Zn and Cu. The ecological risk associated with specific elements decreased in the order Cd > Cu > As > Hg > Pb > Ni > Co ≈ Zn ≈ Cr, and the contamination load index showed that 91% of the samples are polluted by PTEs. Although the carcinogenic risks of Cr, Ni, As, Co, and Cd were low, chronic exposure to several PTEs may affect quality of life. Educational programs, as well as monitoring and greater control on traffic, industry, and construction activities are needed to protect environmental and human health.

Speciation analysis of inorganic As and Sb in urban dust using slurry sampling and detection by fast sequential hydride generation atomic absorption spectrometry

In this work, a methodology for chemical speciation analysis of inorganic As and Sb in urban dust using slurry sampling and detection by fast sequential hydride generation atomic absorption spectrometry is proposed. Doehlert design and desirability function were used to find the optimum conditions for hydride generation (1.0 mol L^-1 HCl and 0.9% m v^-1 NaBH₄). The accuracy of the analytical method was evaluated by analysis of reference material fly ash (BCR 176R), addition and recovery tests for inorganic As species, and comparison of independent methods for Sb determination in urban dust samples. The determination of the total concentrations of As and Sb and their inorganic species presented good accuracy, between 80 ± 1 and 101 ± 6%. Precision was expressed as the relative standard deviation and was better than 4.7% (n = 3). The limit-of-quantification values were 0.23 and 1.03 mg kg^-1 for As and Sb, respectively. The methodology was applied to eight samples of dust collected in an urban area of Salvador and Jaguaquara cities, Bahia, Northeast, Brazil, with an aerodynamic size lower than 38 μm. Concentrations of pentavalent inorganic species (iAs⁵⁺ and iSb⁵⁺) in relation to trivalent species (iAs³⁺ and iSb³⁺) were found in urban dust collected in the city of Salvador, which are regarded as more toxic for both elements. The enrichment factor and geoaccumulation index (I_geo) values showed that for some samples, the concentrations of iAs and iSb presented strong enrichment and, and regarding environment, strong to moderately polluted by iAs and iSb, with an indication of anthropogenic contributions. The occurrence of these inorganic constituents in the urban area of Salvador can be related with intense industrial activities and vehicular traffic.

A mineralogical and chemical investigation of road dust in Philadelphia, PA, USA

Road dust was investigated within Philadelphia, a major United States city with a long history of industrial activities, in order to determine pollution levels. Almost all of the investigated minor elements were enriched relative to the continental crust. Furthermore, mean concentrations of Cr, Co, Cu, and Pb were high compared with those reported in cities in other countries. Lead pollution should be investigated further in Philadelphia, where 8 of the 30 sample sites, including those heavily trafficked by civilians, were at or above the EPA's child safety threshold for Pb in bare soil. High Spearman correlations between Zn and Cu, Zn and Cr, Cu and Cr, and Sn and V, as well as factor analysis of minor elements suggests that the primary sources of these elements were anthropogenic. Potential sources included the breakdown of alloys, non-exhaust traffic emissions, paint, smelting, and industry. We found that higher organic content in road dust may be related to higher traffic densities, which could be due to tire-wear particles. Additionally, higher mean concentrations of Fe, Cr, Cu, and Zn were found at sites with elevated traffic densities. Land use impacted some of the elements not influenced by traffic density, including Co, Sn, and Pb. Bulk mineral content was similar across different land uses and traffic densities and, thus, did not appear to be influenced by these factors. Our research emphasized the complexity of road dust and utilized a more comprehensive approach than many previous studies. This study established fundamental groundwork for future risk assessment in Philadelphia, as it identified several key pollutants in the city. Overall, this assessment serves as an informative reference point for other formerly heavily industrialized cities in the USA and abroad.

Ecological and Human Health Risk Assessment of Heavy Metal Content of Atmospheric Dry Deposition, a Case Study: Kermanshah, Iran

The present study was intended to investigate the ecological and human health risk of cobalt, nickel, and vanadium in the atmospheric dry deposition of the Kermanshah city, Iran, in 2015. Totally 54 samples of atmospheric dry deposition were collected from the three regions of the city with different traffic intensity, and after acid digestion of the samples with ultrapure concentrated HNO₃, the total contents of the metals were determined using inductively coupled plasma optical emission spectrometer (ICP-OES). Also, all statistical analyses were performed using the SPSS statistical package. The atmospheric dry deposition element contents increase according to the following descending order for both autumn seasons: Ni > Co > V. The results of potential ecological risk analysis demonstrated that metals in the samples are in low ecological risk levels, whereas the results of human health risk assessment showed that ingestion is the main exposure pathway of heavy metals in the dust to the local residents compared with inhalation and dermal pathways. Also, the upper limit of the 95% confidence interval (95% UCL) of hazard indices for non-carcinogenic risks of all analyzed metals in the dust samples was within the safe level for both children and adults. On the other hand, the carcinogenic risk levels of Co and Ni were all lower than the acceptable range (10^-6-10^-4) to local citizens. Consequently, the results advocate the necessity of understanding the heavy metal content of atmospheric dry deposition and regular monitoring of air pollution.

Multipotential Toxic Metals Accumulated in Urban Soil and Street Dust from Xining City, NW China: Spatial Occurrences, Sources, and Health Risks

A total of 155 urban soil and 157 dust samples were collected from Xining city (NW, China) with the objective to systematically investigate the spatial occurrences, sources, and health risk status of potential toxic metals (PTMs) bound in urban soil and street dust. Results established by Geographic Information System tools with inverse distance weighted interpolation technique indicated that the spatial status of 24 multi-PTMs varied with their concentration levels in urban soils and street dusts in monitored local areas. However, they had the similar sources in soil and dust. It was found that Bi, Ga, Nb, Ni, Rb, Sr, Th, U, Y, Zr, As, Mn, Nb, Ti, and V would be possibly predominated by nature material, whereas contamination of Ba, Cr, Cu, Pb, and Zn was clearly related to traffic-related sources. Peculiar associations among Sb, Sn, Ce, and Co were possibly enriched in soil and dust very close to the industrial activities. It was noted that PTMs in urban soil was an important contributor to them in dust. Compared with the potential ecological risk index of all PTMs, Sb posed very high risk. The calculated hazard index and cancer risk of all PTMs suggested the acceptable range both to noncarcinogenic and carcinogenic risk to children and adults except for the case of Cr. However, the noncarcinogenic risk for children was usually higher compared with adults. Although the noncarcinogenic and carcinogenic risk were not significant, the risk of Cr above the threshold for children and adults were observed in most local sites, which should be given more attention.

Contamination Level, Source Identification and Risk Assessment of Potentially Toxic Elements (PTEs) and Polycyclic Aromatic Hydrocarbons (PAHs) in Street Dust of an Important Commercial Center in Iran

The geochemical nature and health hazards of potentially toxic elements (PTEs) and polycyclic aromatic hydrocarbons (PAHs) in the street dust of Bandar Abbas, Iran, are investigated in this study based on 27 street dust samples. Mean concentrations of Cu, Pb, Zn, As, Sb, and Hg revealed elevated concentrations as compared to the world soil average. Calculated enrichment factors (EFs) indicated that there is very high contamination in dust particles owing to anthropogenic emissions. Two main sources of PTEs are traffic emissions (Cu, Pb, Zn, Co, Mn, Fe, As, Cd, Sb, and Hg) and resuspended soil particles (Al, Ti, Ni, and Cr). Statistical analysis shows that Al, Mn, Ni, Ti, Cr, Fe, and Co are geogenic, whereas PAHs are mainly derived from traffic emissions. Values of incremental lifetime cancer risk (ILCR), as derived from a modified model of the United State Environmental Protection Agency (USEPA), indicate that Bandar Abbas residents are potentially exposed to high cancer risk, especially via dust ingestion and dermal contact, whereas the level of hazard index (HI), hazard quotients (HQ), and cancer risk associated with exposure to the elements in street dust fall lower than threshold values representative of health risks.

Human health risk assessment of potentially toxic heavy metals in the atmospheric dust of city of Hamedan, west of Iran

The atmospheric dust is an important route of human exposure to kinds of pollutants particularly toxic heavy metals. The current study was carried out to assess the ecological and health risk assessment of Co, Cr, and Mn in the atmospheric dust of city of Hamedan, Iran. In so doing, a total of 54 samples of atmospheric dust were collected from the three regions of the study area in 2014. After acid digestion of samples in the laboratory, the Co, Cr, and Mn contents were determined using inductively coupled plasma-optical emission spectrometer (ICP-OES). The results showed that the average contents (mg kg^-1) of Co, Cr, and Mn in the analyzed samples were 0.23, 0.89, and 8.10, respectively. The results of human health risk assessment showed that ingestion of dust particles is the main exposure route to heavy metals in the dust for the local residents. Also, the upper limit of the 95% confidence interval of hazard indices for non-carcinogenic risks of all analyzed metals in the atmospheric dust was within the safe level (= 1) for both children and adults. The carcinogenic risk levels of Co and Cr were all lower than the acceptable range for local citizens. Based on the results, it can be suggested that special attention be paid to toxic heavy metals that long-term exposure to which via atmospheric dust can have adverse effects on the city resident health.

Risk assessment and source analysis of soil heavy metal pollution from lower reaches of Yellow River irrigation in China

The level of concentration of heavy metal in soil is detrimental to soil quality. The Heigangkou-Liuyuankou irrigation area in the lower-reach of Yellow River irrigation, as home to a large population and a major site to agricultural production, is vulnerable to heavy metal pollution. This study examined soil quality in Heigangkou-Liuyuankou irrigation areas of Kaifeng, China. Pollution in soil and potential risks introduced by heavy metal accumulation were assessed using Nemerow, Geoaccumulation, and Hakanson's ecological risk indices. Statistics and Geographic Information Systems (GIS) were used to model and present the spatiotemporal changes of the pollution sources and factors affecting the levels of pollution. The heavy metals found in the sampled soil are Cr, Ni, Cu, Zn, Cd, Pb, As, and Hg. Among them, Cd is more concentrated than the others. The southwestern region of the studied area confronts the most serious heavy metal pollution. There exist spatial disparities of low concentrations of different heavy metals in the study area. Hg and Cd are found to pose the highest potential ecological risks. However, their risk levels are not the same across the study area. Levels concentration of Ni, Cu, Zn, Cd, Pb, As, and Hg in soil are highly correlated. In combination, they post an additional threat to the ecological environment. Transportation, rural settlements, and water bodies are found to be the major sources of Cr, Ni, Cu, Zn, Cd, Pb, and Hg pollution in the soil; among the major sources, transportation is the most significant factor.

Assessment of oral and lung bioaccessibility of Cd and Pb from smelter-impacted dust

Soil and dust contamination by metals engenders significant environmental and health problems in northern France where a lead smelter was in activity for more than a century. This study aims to examine the long-term effects of the smelter, 10 years after its closedown, on the presence of metal in sidewalk dust for a better assessment of the local population's exposure to Cd and Pb. The investigation included: (i) the metal distribution in different dust particle sizes and (ii) the assessment of metal bioaccessibility via ingestion and inhalation of dust. Seventy-two sidewalk dust samples were collected using a dust-sampling vacuum. The samples were sieved to collect different particle sizes from 0.3 to 1000 μm. The unified bioaccessibility method (UBM) was employed to evaluate the oral bioaccessibility of metals in the different particle sizes. The pulmonary bioaccessible fraction of Cd and Pb via the finest particles was extracted with lung-simulating solution (artificial lysosomal fluid). Ten years after the smelter closedown, (i) a strong relationship was observed between the concentrations of metals in dust and the distance to the former smelter, whatever the particle size; (ii) both total and oral bioaccessible concentrations of metals were high in the finest fraction (0.3-5 μm) and decreased when the particle size increased; (iii) a higher oral bioaccessibility of Cd and Pb was measured in the gastric phase (on average 43% for both metals for all particle sizes) and compared to the gastrointestinal phase (on average 16% for both metals for all particle sizes); and (iv) metal bioaccessibility via inhalation of dust was relatively high (on average 74 and 69%, for Cd and Pb, respectively). The results of the present study suggest that this environmental compartment may be a sensitive and effective indicator of anthropogenic metal contamination and the human exposure in urban areas.

Health Risks and Contamination Levels of Heavy Metals in Dusts from Parks and Squares of an Industrial City in Semi-Arid Area of China

The contamination characteristics and health risk of barium (Ba), cobalt (Co), chromium (Cr), copper (Cu), manganese (Mn), nickel (Ni), lead (Pb), vanadium (V), zinc (Zn), arsenic (As), mercury (Hg), and cadmium (Cd) in samples of dust gathered from squares and parks of Baotou city, an industrial city situated in a semi-arid location of the northwest China were investigated. The contents of Ba, Co, Cr, Cu, Mn, Ni, V, Pb, and Zn in the collected dust samples were determined using X-ray fluorescence spectrometry, while the contents of As and Hg in the dust were investigated by use of the ICP-MS. Further, cadmium was quantified through the atomic absorption spectrometry. Levels of contamination of heavy metals analyzed in the dust samples were evaluated using the Geo-Accumulation index (I_geo) as well as through a Pollution Load Index (PLI). Their health risks to children and adults were evaluated based on the US EPA model of health risk. The findings portrayed that the mean concentrations of Ba, Co Cr, Cu, Pb, V, Cd, and Hg were elevated as compared with their local soil background values. Mean values of I_geo illustrate the order of Co > Cr> Cd > Hg > Pb > Cu > Ba > V > Ni > Mn > Zn > As. It was evident that dusts from the parks and squares were “unpolluted” to “moderately polluted”. Assessment of health risk depicts that ingestion is the foremost route of exposure in regard to the heavy metals, then the dermal adsorption follows. Hg exposure from dust might also set impending health threats to children. Besides, the cancer risks of Co, Cr, Ni, Cd, and As are considered to be within the presently tolerable range.

Analysis of heavy metals in the re-suspended road dusts from different functional areas in Xi'an, China

A study on heavy metal pollution was undertaken in the re-suspended road dusts from different functional areas in Xi'an City of China to investigate the impacts of human activities and land uses on urban environment. The concentrations of Co, Cr, Cu, Mn, Ni, Pb, V, and Zn were determined using X-ray fluorescence spectrometry, and their accumulations were analyzed using enrichment factor. Correlation analysis, principal component analysis, and cluster analysis, combined with the concentration property and enrichment factor, were used to identify the possible sources of heavy metals investigated. The investigated re-suspended road dusts had Co, Cr, Cu, Pb, and Zn concentrations higher than background levels. Samples from different functional areas had diverse heavy metal concentration levels. Co, Cr, Cu, Pb, and Zn presented moderate/significant enrichment in the samples. The source analyses indicated that Mn, Ni, V, Pb, and Zn had the mixed sources of nature and traffic, Cr and Cu mainly originated from traffic source, while Co was primarily derived from construction source. Traffic and construction activities had a significant impact on urban environment. This preliminary research provides a valuable basis for urban environment protection and management.

An index for estimating the potential metal pollution contribution to atmospheric particulate matter from road dust in Beijing

The resuspension of road dust from street surfaces could be a big contributor to atmospheric particulate pollution in the rapid urbanization context in the world. However, to date what its potential contribution to the spatial pattern is little known. Here we developed an innovative index model called the road dust index (RI<105μm) and it combines source and transport factors for road dust particles <105μm in diameter. It could quantify and differentiate the impact of the spatial distribution of the potential risks posed by metals associated with road dust on atmospheric suspended particles. The factors were ranked and weighted based on road dust characteristics (the amounts, grain sizes, and mobilities of the road dust, and the concentrations and toxicities of metals in the road dust). We then applied the RI<105μm in the Beijing region to assess the spatial distribution of the potential risks posed by metals associated with road dust on atmospheric suspended particles. The results demonstrated that the road dust in urban areas has higher potential risk of metal to atmospheric particles than that in rural areas. The RI<105μm method offers a new and useful tool for assessing the potential risks posed by metals associated with road dust on atmospheric suspended particles and for controlling atmospheric particulate pollution caused by road dust emissions.

Grain Size Distribution and Health Risk Assessment of Metals in Outdoor Dust in Chengdu, Southwestern China

A total of 27 outdoor dust samples from roads, parks, and high spots were collected and analyzed to investigate the contamination of 11 metals (Cr, Mn, Co, Ni, Cu, Zn, As, Sr, Cd, Sb, and Pb) in Chengdu, China. The results showed that the samples from the high spots exhibited the highest heavy metal level compared with those from the roads and the parks, except for Ni, Cu, and Pb. The dust was classified into five grain size fractions. The mean loads of each grain size fraction of 11 determined metals displayed similar distribution, and the contribution of median size (63-125, 125-250, 250-500 μm) fractions accounted for more than 70% of overall heavy metal loads. The health risk posed by the determined metals to human via dust ingestion, dermal contact, and inhalation was investigated. Oral and respiratory bioaccessible parts of the metals in dust were extracted using simulated stomach solution and composite lung serum. The mean bioaccessibilities of 11 investigated metals in the gastric solution were much higher than those in the composite lung serum, especially Zn, Cd, and Pb. Ingestion was the most important exposure pathway with percentage greater than 70% for both children and adults. Risk evaluation results illustrated that children in Chengdu might suffer noncarcinogenic risk when exposed to outdoor dust. Given that the cancer risk values of Pb and Cr larger than 1 × 10(-4), potential carcinogenic risk might occur for Chengdu residents through outdoor dust intake.

Residents health risk of Pb, Cd and Cu exposure to street dust based on different particle sizes around zinc smelting plant, Northeast of China

The residents health risk of Pb, Cd and Cu exposure to street dust with different particle sizes (<100 and <63 μm) near Huludao Zinc Plant (HZP) was investigated in this study. The average concentrations of Pb, Cd and Cu in the <100-μm and <63-μm dust were 1,559, 178.5, 917.9 and 2,099, 198.4, 1,038 mg kg(-1), respectively. It showed that smaller particles tended to contain higher element concentrations. Metals in dust around HZP decreased gradually from the zinc smelter to west and east directions. There was significantly positive correlation among Pb, Cd and Cu in street dust with different particle sizes. The contents of Pb, Cd and Cu in dust increased with decreasing pH or increasing organic matter. Non-carcinogenic health risk assessment showed that the health index (HI) for children and adult exposed to <63-μm particles were higher than exposed to <100-μm particles, which indicated that smaller particles tend to have higher non-carcinogenic health risk. Non-carcinogenic risk of Pb was the highest in both particle sizes, followed by Cd and Cu. HI for Pb and Cd in both particle sizes for children had exceeded the acceptable value, indicated that children living around HZP were experiencing the non-carcinogenic health risk from Pb and Cd exposure to street dust.

Heavy metal contamination assessment and partition for industrial and mining gathering areas

Industrial and mining activities have been recognized as the major sources of soil heavy metal contamination. This study introduced an improved Nemerow index method based on the Nemerow and geo-accumulation index. Taking a typical industrial and mining gathering area in Tianjin (China) as example, this study then analyzed the contamination sources as well as the ecological and integrated risks. The spatial distribution of the contamination level and ecological risk were determined using Geographic Information Systems. The results are as follows: (1) Zinc showed the highest contaminant level in the study area; the contamination levels of the other seven heavy metals assessed were relatively lower. (2) The combustion of fossil fuels and emissions from industrial and mining activities were the main sources of contamination in the study area. (3) The overall contamination level of heavy metals in the study area ranged from heavily contaminated to extremely contaminated and showed an uneven distribution. (4) The potential ecological risk showed an uneven distribution, and the overall ecological risk level ranged from low to moderate. This study also emphasized the importance of partition in industrial and mining areas, the extensive application of spatial analysis methods, and the consideration of human health risks in future studies.