Metals In Road Dust Research Articles

Contribution of road dust from Low Impact Development (LID) construction sites to atmospheric pollution from heavy metals

The re-suspension of road dust due to intense Low Impact Development (LID) construction activities may be a major contributor to atmospheric metal pollution. However, the distribution characteristics, mobility potential, and pollutant load of atmospheric particles at LID construction sites are not clear. Consequently, management practices to mitigate air pollution from LID construction are lacking. We investigated the atmospheric metal pollution from road dust produced during different construction stages of rain gardens and porous pavements and estimated the ecological risks posed by the heavy metals. Although concentrations of heavy metals in road dust at LID construction sites were lower than at sites without LID construction, the ecological risks posed by the atmospheric heavy metals at LID construction sites were generally higher due to the greater mass of road dust produced during LID construction. Hence, LID management practices should focus on the removal of road dust, especially finer particles (<44 μm) produced during early construction stages. In roads, the zones influenced by LID construction is related to road types based on traffic volume; these road types in descending order of zone influenced by LID construction are: arterial road (400–600 m) > collector road (100–150 m) > access road (50–100 m) > laneway (30–50 m). Based on the study sites, we estimate LID construction in China will contribute 2.31 and 6.23 times as much as the current load of atmospheric particles by 2020 and 2030; and we project atmospheric heavy metals will be 1.45–2.18 and 2.82–4.73 times greater than the current load by 2020 and 2030 from the intense LID construction. Based on our results, several regulatory recommendations are presented to mitigate air pollution at LID construction sites.

Ecological and human health risk assessment of heavy metal contamination in road dust in the National Capital Territory (NCT) of Delhi, India.

The present study was carried out to determine the contamination levels of heavy metals in road dust of the National Capital Territory of Delhi (NCT), India and its consequent effect on human and environment. The levels of heavy metals (Pb, Zn, Cu, Cr, Ni, Mn, and Fe) in 9 districts (Z1-Z9) of NCT were monitored and the corresponding human health risk was estimated. District-wise evaluation of heavy metal pollution in the road dust was performed. The mean concentrations of Pb, Zn, Cu, Ni, Cr, Mn, and Fe in the road dust samples over the study area were 164.2 ± 53.2, 200.7 ± 45.3, 99.9 ± 64.8, 24.7 ± 5.7, 57.7 ± 25.9, 241.4 ± 39.8, and 11113.9 ± 1669.7 mg kg-1, respectively. PLI showed a high pollution load in the monitored nine locations, indicating an alarming condition and the urgent need for immediate remedial actions. Ecological risk assessment depicted that a 74% risk was attributed to Pb. Hazard quotient (HQ) values indicated that ingestion was the major pathway of road dust heavy metal exposure to human beings. Hazard index values showed that there was no probable non-carcinogenic risk of the heavy metals present in the road dust of the area. Children were found vulnerable to the risks of road dust metals. The findings of this study showed the alarming status of heavy metal contamination to road dust in NCT and the associated risk to human health.

Deciphering source contributions of trace metal contamination in urban soil, road dust, and foliar dust of Guangzhou, southern China

Trace metal contamination prevails in various compartments of the urban environment. Understanding the roles of various anthropogenic sources in urban trace metal contamination is critical for pollution control and city development. In this study, the source contribution from various contamination sources to trace metal contamination (e.g., Cu, Pb, Zn, Co, Cr and Ni) in different environmental compartments in a typical megacity, Guangzhou, southern China, was investigated using the receptor model (Absolute Principal Component Scores-Multiple Linear Regression, APCS-MLR) coupled with the Kriging technique. Lead isotopic data and APCS-MLR analysis identified industrial and traffic emissions as the major sources of trace metals in surface soil, road dust, and foliar dust in Guangzhou. Lead isotopic compositions of road dust and foliar dust exhibited similar ranges, implying their similar sources and potential metal exchange between them. Re-suspended soil contributed to 0–38% and 25–58% of the trace metals in the road dust and foliar dust, respectively, indicating the transport of the different terrestrial dust. Spatial distribution patterns implied that Cu in the road dust was a good indicator of traffic contamination, particularly with traffic volume and vehicle speed. Lead and Zn in foliar dust indicated mainly industrial contamination, which decreased from the emission source (e.g., a power plant and steel factory) to the surrounding environment. The spatial influence of industry and traffic on the contamination status of road dust/foliar dust was successfully separated from that of other anthropogenic sources. This study demonstrated that anthropogenic inputs of trace metals in various environmental compartments (e.g., urban soil, road dust, and foliar dust) can be evaluated using a combined APCS-MLR receptor model and geostatistical analysis at a megacity scale. The coupled use of APCS-MLR analysis, geostatistics, and Pb isotopes successfully deciphered the spatial influence of the contamination sources in the urban environment matrix, providing some important information for further land remediation and health risk assessment.

Environmental Assessment of Some Heavy Metals Pollution in Street Dust in the Industrial Areas of Ahvaz

Background: High concentrations of heavy metals in street dust are considered to be a serious risk to human health and the environment. Therefore, investigating the concentration of heavy metals to monitor pollution and preserve the quality of the environment is essential. Objectives: This study aimed to examine the concentration, enrichment factor (EF), pollution index (PI), and Nemrow integrated pollution index (NIPI) of potentially heavy metals including Cr, Cu, Cd, Pb, Zn, Ni, V, As, and Co in street dust in the industrial areas of Ahvaz. Methods: A total of 29 dust samples were collected from sidewalks of main streets of industrial areas of Ahvaz and were analyzed by the inductively coupled spectroscopy (ICP-OES) method. Results: The average concentration of heavy metals in Pb, Zn, Cu, Cr, Cd, Ni, V, As, and Co was respectively: 86, 999, 50, 57, 0.3, 58, 184, 6, and 13 (mg/kg), respectively. The mean concentration of all heavy metals in the samples of dust in the industrial areas of Ahvaz was several times higher than that of baseline values. Based on the average EF in the study area, Zn and Pb have extremely high enrichment. In addition, Zn, V, and Pb, with the highest PI average, displayed high pollution. In addition, the evaluation of NIPI showed that 100% of samples have high pollution. Conclusions: The source of pollution of studied metals was anthropogenic, such as urban industrial facilities, transport, vehicle traffic, and burning of fossil fuels in the studied area. Generally, some protective protocol are proposed to reduce the level of heavy metals pollution in the city of Ahvaz, such as environmental control of gases produced by industries and factories, increase of green space, conversion of liquid fuel to gaseous, and use of public transportation.

Assessment of trace elements concentration in road dust around the city of Kuala Lumpur

This study aimed to assess the concentrations and health effect of heavy metals (Cd, Cu, Cr, Ni, Pb and Zn) in road dust of selected locations in the city of Kuala Lumpur. Sampling was conducted for three times at four locations namely Jalan Tun Razak, Jalan Raja Abdullah, Jalan TAR and Jalan Ayer Molek. The concentration of heavy metals in road dust was analyzed by using ICP-MS. The study found that Jalan TAR has the highest concentrations for the heavy metals Cd (0.23 ± 0.04 mg/kg), Cu (116.39 ± 38.77 mg/kg), Ni (83.29 ± 23.66 mg/kg), Pb (43.53 ± 7.00 mg/kg) and second highest for Cr (34.69 ± 3.57 mg/kg) and Zn (86.22 ± 23.07). The pollution level of heavy metals in road dust were assessed by Pollution Index and Pollution Load Index, showing that all locations are highly contaminated except Jalan Ayer Molek. Health risk assessment was determined to access the health effect of carcinogenic and non-carcinogenic to adults and children caused by exposure of heavy metals in road dust. Based on the integrated HI for children at all locations are more than 1. Indicating great chance of non-carcinogenic effects. All incremental lifetime cancer risk (ILTCR) values for adult and children at all locations are within acceptable limit. Traffic and activities that take place in these four locations are the sources of heavy metals. Jalan TAR which is loaded with commercial activities is the most polluted location followed by Jalan Raja Abdullah (commercial area), Jalan Tun Razak (highway area) and Jalan Ayer Molek (residential area).

Assessment of heavy metals in roadside dust along the Abu Dhabi–Al Ain National Highway, UAE

Concentrations of key heavy metals (Pb, Zn, Cd, Ni, Cr, Mn, As, and Hg) have been investigated in roadside dust collected from Abu Dhabi–Al Ain National Highway in UAE. The heavy metals contents were analyzed by atomic absorption spectrometer. Heavy metal levels varied widely from 227.9 to 2765, 19 to 1540, 37.4 to 398.6, 20.1 to 123, 0.3 to 0.7, 0.1 to 0.9, 0.1 to 0.7, and 0.1 to 0.5 mg/kg for Mn, Cr, Zn, Pb, Cd, Hg, Ni, and As, respectively. The spatial distribution pattern showed that different sources of roadway metal emissions dominate at specific locations. Peaks in heavy metal concentrations were frequently observed in locations with high traffic volume, road intersections and junctions, gas and bus stations. Decreased levels of heavy metals were measured in locations with low traffic loadings and in close proximity to farm and forest areas. In addition to traffic-related heavy metals, emissions from fossil fuel and industries remain of significance. Natural sources, through regular dust storms, are important contributors to the observed metal levels. Enrichment factor indicated that As and Ni were entirely originated from crustal sources. Cd, Zn, Pb, and Mn were moderately enriched and are probably derived from mixed sources (traffic flows, gas stations, construction and agricultural activities, among others). Road dust was significantly enriched in Cr and Hg indicating their dominant anthropogenic origin. The average geo-accumulation index values suggested that road dust are uncontaminated with Mn, Ni, and As, uncontaminated to moderately contaminated with Zn and Pb, and moderately contaminated with Cr, Cd, and Hg. The contamination factors indicated very highly contaminated road dust with Cr and Hg, considerably contaminated with Cd, and moderately contaminated with Mn, Zn, and Pb. Results of ecological risk assessment revealed that all heavy metals in road dust pose low risk to local ecosystems, except for Cd and Hg, which constitute potentially considerable risk and high risk, respectively.

Determination and Contamination Assessment of Heavy Metals in Street Dust from Different Types of Land-Use in Kathmandu District, Nepal

A total of forty seven street dust samples, collected from five different types of land use viz., industrial, urban, heavy traffic road, residential and undisturbed areas (control) of Kathmandu district (Nepal), were subjected to characterize the physico-chemical parameters such as pH, electrical conductance (EC), total alkalinity (T. Alk), total organic carbon (TOC) and particle size distribution. Four heavy metals of Cd, Cu, Pb and Zn were determined in dust samples using flame atomic absorption spectrophotometer (FAAS). It was found that all types of dust samples possessed alkaline nature along with variation in EC, T. Alk and TOC values. Results revealed that the dust of industrial areas contained high concentrations of Zn (143.3 mg/kg) and Cu (106.42 mg/kg), whereas the heavy traffic areas were mainly affected by Cd (0.90 mg/kg) and Pb (70.08 mg/kg). The average metal concentrations of Cd, Cu, Pb and Zn in dust of all the types of land use in Kathmandu were found to be 0.73, 68.86, 51.46 and 104.30 mg/kg and their average metal enrichment factors were 2.28, 5.50, 1.92 and 3.17, respectively. The results were also compared against heavy metals status in street dust from various cities/countries around the world. Pollution indices such as contamination factor (CF), degree of contamination (CD) and geo-accumulation index (Igeo) showed different classes of metal contamination in street dust of Kathmandu indicating traffic emission, automobiles, construction and demolition activities and other anthropogenic activities as the potential sources.

Investigations of the chemical distribution of heavy metals in street dust and its impact on risk assessment for human health, case study of Radom (Poland)

This work investigated the ecological and health hazards caused by heavy metals present in urban street dust of Radom (Poland). The objectives of this study were to improve the estimation of exposure doses of toxic metals based on their distribution patterns in street dusts and to assess the noncarcinogenic health risk for the residents. Zinc (Zn), manganese (Mn), and lead (Pb) were mainly associated with the reducible fraction, copper (Cu) with the oxidizable fraction, and iron (Fe), nickel (Ni), and chromium (Cr) with the residual fraction. The contents of short-term and long-term labile fractions of the metals were used to assess a direct health risk, a potential health risk and an overall human health risk. The level of the overall risk quantified by the cumulative total labile fraction-HI (tlf-HIc ): 3.91E-01 (children) and 3.85E-02 (adults) was lower than the safety limit of unity. The metal that contributed the most to the overall health risk was Pb: 34% (children) and 31% (adults), while Zn and Ni had the least contribution (3% and 2% for both children and adults). It was shown that the risk assessment based on the pseudo-total content of metals can overestimate the health risk by nearly two times when compared to the assessments based on the total content of labile fractions.

Distribution and health risk assessment of heavy metals in road dust from an industrial estate in Trinidad, West Indies

ABSTRACTRoad dust from the Point Lisas Industrial Estate in Trinidad, West Indies was investigated to determine its heavy metal content and the associated health risks. The average concentrations of Cd, Cr, Cu, Mn, Ni, Pb and Zn were 3.44, 37.69, 58.16, 770.69, 35.61, 68.50 and 342.53 μg/g, respectively. The health risks due to exposure to heavy metals in road dust were assessed based on the US EPA’s Health Risk Assessment Model for both carcinogenic and non-carcinogenic effects. The health risk assessment indicated that the ingestion pathway was the main exposure route to heavy metals from road dust; however, HI values suggested no potential health risks to both children and adults. The cancer risks for Cd, Cr and Ni were less than 10–6 and the resulting exposure was therefore considered low.

The influence of heavy metals in road dust on the surface runoff quality: Kinetic, isotherm, and sequential extraction investigations

This study examines the adsorption and desorption characteristics of heavy metals in road dust (RD) for the aspect of integrated stormwater management. The chemical fractionations of Cu, Zn, Ni, and Cd were determined by a three-step sequential extraction protocol. Pseudo-first-order and Pseudo-second-order kinetic models, along with Langmuir, Freundlich, and Temkin isotherms were adopted to simulate the batch experimental data. The proportional shift of metals' chemical fractionations in original RD, adsorption equilibrium, and desorption equilibrium were determined. Results show that RD has a remarkable affinity to adsorb heavy metal within a short time. The adsorption processes were well described by the Pseudo-second-order kinetic model (R2 = 0.98–0.99) and Freundlich isotherm (R2 = 0.89–0.98) for most of the given metals indicating that the chemical adsorption was probably the rate-controlling step and the binding energy for each site was not identical. The maximum adsorption capacities for Cu, Cd, Zn, and Ni were 6300 mg kg−1, 5800 mg kg−1, 4000 mg kg−1, and 3200 mg kg−1, respectively. A linear fit to the equilibrium pH and the total amounts of the adsorbed metals indicates a strong pH-dependent adsorption. According to the proportional shift of metals’ chemical fractionations during the adsorption and desorption processes, the exchangeable fractions of heavy metals in RD were irreversible. It suggests that a portion of the surface sites of RD would be not exchangeable once it was occupied.

Source identification and risk assessment of heavy metals in road dust of steel industrial city (Anshan), Liaoning, Northeast China

The purpose of the study was to acquire the source and evaluate the risk posed by heavy metals in road dust of steel industrial city (Anshan), Liaoning, Northeast China. Potential ecological risk index (RI), pollution index (PI) and geo-accumulation index (Igeo) were applied to evaluate the heavy metal pollution level, and the carcinogenic risk (RI) and hazard index (HI) were calculated to estimate the human health risk. The geographic information system maps clearly reveal the hot spots of heavy metal spatial distribution. Principle component analysis (PCA) and cluster analysis (CA) classified heavy metals into three groups. The metal Zn and Pb originate from the traffic emission, while Cd, Cr, Fe, Mn, Ni and Sb primarily come from industrial activities. These two pathways were the major source of heavy metals pollution by positive matrix factorization (PMF). The Igeo and PI values of heavy metals were decreased in the following order: Cd > Sb > Zn > Fe > Pb > Cu > Cr > Sn > Mn > Ni. The RI index showed the heavy metals were moderate to very high potential ecological risk. The HI values for children and adults presented a decreasing order of Cr > Pb > Ni > Cu > Cd > Zn. The HI also predicted a possibility of non-carcinogenic risk for children living in urban areas in comparison with adults.

Characterization and risk assessment of heavy metals in road dust from a developing city with good air quality and from Shanghai, China.

To investigate the differences in characteristics of heavy metals associated with different levels of ambient air quality, we collected road dust samples from Beihai (BH) and Shanghai (SH). The mean concentrations of Ni, Cr, Zn, and Cu in BH samples were one to four times the background concentrations in soil, whereas the concentrations of Cd, Cr, Mn, Zn, Cu, and Pb in SH were one to three times the background concentrations. The geo-accumulation index (Igeo) indicated widespread moderate contamination by Zn and high contamination near industrial areas by Ni and Cr in BH, whereas in SH was partly moderately contaminated by Pb, Cu, and Zn. The potential ecological risk index ([Formula: see text]) indicated the low risk posed by all metals in both BH and SH. However, special attention should be given to the maximal [Formula: see text] values, such as considerable risk for Hg ([Formula: see text] = 148.7) and high risk for Ni (254.1) in BH, respectively. According to the health risk assessment results, there were no non-carcinogenic or carcinogenic risks (CR) posed by heavy metals in road dust collected from BH and SH. Non-carcinogenic risks due to Cr for children in both BH (0.36) and SH (0.24) were relatively high compared to other metals, and a maximal CR value for Cr (2.7 × 10-6) was found to pose a potential carcinogenic risk near the industrial area in BH. Compared with those in developed cities, the health risks in BH related to Cu, Pb, and Zn from motor vehicle emissions were relatively low, but those related to Ni and Cr from local industrial activity in road dust were relatively high.

Assessment of Heavy Metals in Street Dusts of Tehran Using Enrichment Factor and Geo-Accumulation Index: A

: Street dust contains small matters coming from motor combustion and other anthropogenic sources. These elements are known as indicators of heavy metals, which have an important role in environmental pollution. The purpose of this study is to evaluate the degrees of arsenic, cadmium, copper, lead, and zinc pollution in street dust by using of the geo-accumulation index and enrichment factor. For sampling, 35 points are randomly defined by using the geographic information system. The metals were detected using acid digestion inductively coupled plasma optical emission spectrometry. The order of geo-accumulation index of analyzed heavy metals were: arsenic < lead < cadmium < zinc < copper. The copper levels can be considered as “moderately to heavily polluted” status. The assessment results of enrichment factor and geo-accumulation index showed that Arsenic did not have any noticeable concern, while enrichment factor of lead and zinc had moderate enrichment, and cadmium and copper had moderately severe enrichment. The average levels of studied metals were higher than the mentioned background level. There are variant elements causing high levels of heavy metals in street dust of Tehran. For instance, the extensive traffic following by the vehicles speed and braking, power plants, and industrial emissions are the main factors. Therefore, considering this information as an alarming sign for the safety of our environment is needed.

Assessment of selected Physicochemical Parameters and Trace Metals in Street Dust along roads in Enugu Metropolis, Nigeria

Trace metals, present above permissible limits are an ever present threat to public health due to their toxicity and carcinogenic nature. They can also impair important biochemical processes in animals and affect plant growth. The assessment of these pollutants, commonly found in street dust, is important for environmental health quality. The present work investigated the level, sources and assessment of trace metal pollution in street dust along selected roads in Enugu metropolis. A total of 32 dust samples were collected from 10 major roads and analyzed for trace metal content with a Buck 210VGP AAS after strong tri-acid digestion. Values were obtained for 9 trace metals in the dust samples within the following ranges (in mg kg-1): Cr(0.67 - 3.67), Mn (2.33 - 7.67), Fe (408.33 - 512.33), Co (3.00 - 61.75), Ni (39.67 - 193.67), Cu (11.50 - 90.00), Zn (1.00 - 31.67), Cd (0.00 - 1.33), and Pb (0.00 - 46.67). pH values, electrical conductivity (EC) and total organic matter (TOM) of the samples ranged from 6.75 - 8.39, 556 - 578.67 μS/cm and 1.27 - 10.35% respectively. The geoaccumulation index (Igeo) shows moderate pollution of Cd and Pb in the roads. The integrated pollution index (IPI) also showed moderate to high level of pollution of the metals in the following order: Cu&lt;Pb&lt;Ni&lt;Cd. Multivariate statistical analysis identified the major sources of these trace metals along the roads as vehicles (from parts and emissions) and road infrastructure.

Human health risk assessment of heavy metals in road dust collected in Cracow

Road dust is viewed as one of the major contributors for metal pollution in urban environment and long-term exposure can cause chronic damage through ways of inhalation, ingestion, and dermal contact so they pose a great threat on human health. The article presents a study conducted to determine the concentrations of seven heavy metals in road dust from a chosen street in Cracow, and the impact of heavy metals contamination in surface street dust on human health using Health Risk Assessment. The health risk was assessed using Hazard Quotient (HQ), Health Index (HI) and Carcinogenic Risk (RI).

Spatial Characteristics of Heavy Metals in Street Dust of Coal Railway Transportation Hubs: A Case Study in Yuanping, China.

Coal is a vital basic energy source in China, and rail serving is its major mode of transportation. Heavy metals in street dust surrounding the coal railway do harm to the environment and pose a potential risk to human health. This paper aims to identify the effects of coal transportation hubs on heavy metals in street dust. The geoaccumulation index and ecological risk index were used to assess the contamination levels of the following elements in Yuanping, Shanxi: arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), mercury (Hg), nickel (Ni), lead (Pb), and zinc (Zn). The levels of contamination of these heavy metals in soils were compared to those in street dust, and the difference between the railway’s and mining’s impacts on dust’s heavy-metal concentrations was explored. The results indicated that Cr and Pb in street dust were mainly affected by coal railway transportation, and the interaction effect of coal railway transportation and mining was greater than either of them alone. A potential control and prevention zone for Cr and Pb extending 1 km to both sides of the railway was identified. This work proves that coal railway transportation has certain effect on heavy metals in street dust and provides a scientific approach for future environmental impact assessments of coal transportation via railway.

Spectroscopic and Voltammetric Analysis of Platinum Group Metals in Road Dust and Roadside Soil

The emission of toxic compounds by increasing anthropogenic activities affects human health and the environment. Heavy road traffic and mining activities are the major anthropogenic activities contributing to the presence of metals in the environment. The release of palladium (Pd), platinum (Pt), and rhodium (Rh) into the environment increases the levels of contamination in soils, road sediments, airborne particles, and plants. These Pd, Pt, and Rh in road dusts can be soluble and enter aquatic environment posing a risk to environment and human health. The aim of this study is to determine the levels of Pd, Pt, and Rh with spectroscopy and voltammetric methods. Potential interferences by other metal ions (Na(I), Fe(III), Ni(II), Co(II)) in voltammetric methods have also been investigated in this study. At all the sampling sites very low concentrations of Pd, Pt, and Rh were found at levels that range from 0.48 ± 0.05 to 5.44 ± 0.11 ng/g (dry weight (d.wt)) for Pd(II), with 17.28 ± 3.12 to 81.44 ± 3.07 pg/g (d.wt) for Pt(II), and 14.34 ± 3.08 to 53.35 ± 4.07 pg/g (d.wt) for Rh(III). The instrumental limit of detection for Pd, Pt, and Rh for Inductively Coupled Plasma Quadrupole-based Mass Spectrometry (ICP-QMS) analysis was found to be 3 × 10−6 µg/g, 3 × 10−6 µg/g and 1 × 10−6 µg/g, respectively. In the case of voltammetric analysis the instrumental limit of detection for Pd(II), Pt(II), and Rh(III) for differential pulse adsorptive stripping voltammetry was found to be 7 × 10−8 µg/g, 6 × 10−8 µg/g, and 2 × 10−7 µg/g, respectively. For the sensor application, good precision was obtained due to consistently reproduced the measurements with a reproducibility of 6.31% for Pt(II), 7.58% for Pd(II), and 5.37% for Rh(III) (n = 10). The reproducibility for ICP-QMS analysis were 1.58% for Pd(II), 1.12% for Pt(II), and 1.37% for Rh(III) (n = 5). In the case of repeatability for differential pulse adsorptive stripping voltammetry (DPAdSV) and ICP-QMS, good standard deviations of 0.01 for Pd(II); 0.02 for Pt(II), 0.009 for Rh(III) and 0.011 for Pd, 0.019 for Pt and 0.013 for Rh, respectively.

Pollution assessment and health risks evaluation of (metalloid) heavy metals in urban street dust of 58 cities in China.

In this research, we conducted a statistical analysis of ten (metalloid) heavy metals, including Cu, Hg, Cd, Zn, Pb, As, Ni, Cr, Co, and Mn in urban dust of 58 cities in China from 2000 to 2018, and then we analyzed the statistic characters, pollution statue, and health risks of ten heavy metals. Results showed that (1) the maximum (average) values of ten (metalloid) heavy metals in the street dust of 58 Chinese cities all exceeded Chinese background values, and there were obvious differences in contents of heavy metals of Hg, Zn, Co, Cr, and As between industry cities and common cities. A provincial spatial distribution analysis revealed large variations of distributions of heavy metals Cu, Zn, Pb, and Cr, which distributed in cities mainly located in southern, central, and eastern China, ranging from relatively low to high levels, while Ni, Co, and Mn mainly distributed in southern and central China. This is mainly associated with the mining of the cities. (2) Igeo analysis showed that there was no obvious Ni, Mn, or Co pollution in street dust, while the other tested heavy metals had a range of low to high levels of pollution, in particular, seven metals among them had low to extremely strong levels of pollution (Igeo values between 0 and 7.154), and the average Igeo values were in the following order: Cd > Hg > Zn > Pb > Cu > As>Cr > Mn > Co > Ni. (3) Health risks evaluation showed that of the three exposure ways, the HQing from hand-mouth intake was the most common exposure route for both children and adults, especially for children, followed by skin absorption and respiration ways. This research showed that the HI value for children was higher than 1, indicative of no carcinogenic risks, while the HI values for both male and female were lower than 1, indicative of carcinogenic risks; calculation of carcinogenic risk through respiratory route showed that the risks of five elements were within the range 10-6-10-4, indicative of carcinogenic risk, among which Cr accounting exceeded 90% of total, which needs to be paid more attention to.

Uncertainty analysis in source apportionment of heavy metals in road dust based on positive matrix factorization model and geographic information system

Based on 36 road dust samples from an urbanized area of Beijing in September 2016, the information about sources (types, proportions, and intensity in spatial) of heavy metals and uncertainties were analyzed using positive matrix factorization (PMF) model, bootstrap (BS), geographic information system (GIS) and Kriging. The mean concentration of most heavy metals was higher than the corresponding background, and mean concentration of Cd was six times of its background value. Types and proportions of four sources were identified: fuel combustion (33.64%), vehicle emission (25.46%), manufacture and use of metallic substances (22.63%), and use of pesticides, fertilizers, and medical devices (18.26%). The intensity of vehicle emission and the use of pesticides, fertilizers, and medical devices were more homogeneous in spatial (extents were 1.285 and 0.955), while intensity of fuel combustion and the manufacture and use of metallic substances varied largely (extents were 4.172 and 5.518). Uncertainty analysis contained three aspects: goodness of fit, bias and variability in the PMF solution, and impact of input data size. Goodness of fit was assessed by coefficient of determination (R2) of predicted and measured values, and R2 of most species were higher than 0.56. Influenced by an outlier, R2 of Ni decreased from 0.59 to 0.11. Result of bootstrap (BS) showed good robust of this four-factor configuration in PMF model, and contributions of base run of factors to most species were contained in the small interquartile range and close to median values of bootstrap. Size of input data also had influence on results of PMF model. Residuals changed largely with the increase of number of site, it varied at first and then kept stable after number of site reached 70.

A comparison of elemental presence in UK and Kuwait road dust

The monitoring of concentrations of metals in road dust can be used in evaluating vehicular contributions to the environment. Here we compare the efficacy of several analytical techniques for such samples: XRF, SEM/EDX and ICP-MS, providing for both qualitative and absolute quantitative analysis. To-date we have made evaluation of key elemental levels from roadside dust sampled at different locations within the University of Surrey and the Kuwait Research Institute, in so-doing also investigating the influence of engine size (Kuwaiti vehicles tending to be of larger engine capacity than those in the UK) and the influence of climate, maritime and arid in the present case. With a total of 36 street dust samples collected to-date, 18 have now been analyzed, elemental concentrations being reported for Mg, Al, Ti, Mn, Fe, Co, Zr, Mo, Ba, Tl, V, Rd, Pb, Cu, Zn, Ni, Cr, Cd, As, Hg and Au. For University of Surrey samples, obtained at three different times of the year, SEM/EDX findings range from below the lower limit of detection for Ag, through to 4.7 × 10−6 mg/m2 for Co, up to 3.6 × 10−2 mg/m2 for Fe. Using ICP-MS on sieved University of Surrey road dust samples similarly taken at different times of the year, mean particle dimensions < 45 µm (i.e. respirable dust) have been obtained yielding elevated elemental concentrations in units of mg/kg (ppm), with mean values as follows: Cu (70.4 mg/kg), Zn (288 mg/kg,) Al (3081 mg/kg) and Fe (14,133 mg/kg). These values can be compared against that for Co (3.5 mg/kg) and V (12.3 mg/kg), a primary source of the latter deriving from their use in vehicle tyres production, also for 78.0 mg/kg (Pb). Other toxic metals found in the Guildford and Kuwait samples in different low concentrations were Ti, Cr, and Ba. The concentrations of Pb were found to be low compared to previous analyses, attributable to modern restrictions on Pb in fuel. Au and Ag were also detected, albeit in very low concentrations in the samples from both countries, in particle sizes of the order of 0.5 µm. In summary, present study shows a number of elements presenting at particularly elevated concentrations, a major source being motorpart wear debris.