Heavy Metals In Road Dust Research Articles

Sources, Distribution, and Health Implications of Heavy Metals in Street Dust across Industrial, Capital City, and Peri-Urban Areas of Bangladesh

Heavy metals in road dusts can directly pose significant health risks through ingestion, inhalation, and dermal contact. This study investigated the pollution, distribution, and health effect of heavy metals in street dust from industrial, capital city, and peri-urban areas of Bangladesh. Inductively coupled plasma mass spectrometry (ICP-MS) examined eight hazardous heavy metals such as Zn, Cu, Pb, Ni, Mn, Cr, Cd, and Co. Results revealed that industrial areas showed the highest metal concentrations, following the order Mn > Zn > Cr > Pb > Ni > Co > Cd, with an average level of 444.35, 299.25, 238.31, 54.22, 52.78, 45.66, and 2.73 mg/kg, respectively, for fine particles (≤20 μm). Conversely, multivariate statistical analyses were conducted to assess pollution levels and sources. Anthropogenic activities like traffic emissions, construction, and industrial processing were the main pollution sources. A pollution load index revealed that industrial areas had significantly higher pollution (PLI of 2.45), while the capital city and peri-urban areas experienced moderate pollution (PLI of 1.54 and 1.59). Hazard index values were below the safety level of 1, but health risk evaluations revealed increased non-carcinogenic risks for children, especially from Cr, Ni, Cd, and Pb where Cr poses the highest cancer risk via inhalation, with values reaching 1.13 × 10−4–5.96 × 10−4 falling within the threshold level (10−4 to 10−6). These results underline the need for continuous environmental monitoring and pollution control in order to lower health hazards.

Sources Analysis and Health Risk Assessment of Heavy Metals in Street Dust from Urban Core of Zhengzhou, China

Fifty-one street dust samples were systematically collected from the urban core of Zhengzhou, China, and analyzed for potentially toxic metals. The concentrations of vanadium (V), manganese (Mn), copper (Cu), zinc (Zn), arsenic (As), lead (Pb), and nickel (Ni) in the samples surpassed the background values of the local soil, indicating a notable potential for contamination. Spatially, the traffic area was the most polluted with a total heavy metal concentration of Cu, Zn, As, Pb, and Ni, while the pollution levels were lower in the culture and education area and commercial area with total concentrations of V and Mn. Seasonal variations were discerned in the concentrations of heavy metals, with V, Cu, Zn, and As exhibiting heightened levels during the fall and winter, while Mn, Ni, and Pb reached peaks in the spring season. Zn exhibited the highest mean geo-accumulation index (Igeo) value at 2.247, followed by Cu at 2.019, Pb at 0.961, As at 0.590, Ni at 0.126, Mn at −0.178, and V at −0.359. The potential ecological risk index (RI) in the traffic-intensive area markedly exceeded other functional areas. Health risk assessments showed that children were more vulnerable to heavy metal exposure than adults, particularly through the ingestion pathway. Correlation analysis, principal component analysis (PCA), and cluster analysis (CA) were applied in conjunction with the spatial–temporal concentration patterns across various functional areas to ascertain the plausible sources of heavy metal pollutants. The results indicated that heavy metals in the urban street dust of Zhengzhou were multifaceted, stemming from natural processes and diverse anthropogenic activities such as coal burning, industrial emissions, traffic, and construction operations.

Health Risk Assessment of Road-Dust-Bound Heavy Metals via Ingestion Exposure from One Typical Inland City of Northern China: Incorporation of Sources and Bioaccessibility

Heavy metals in road dust pose potential health risks to humans, while oral bioaccessibility and sources are all important factors influencing this health risk. However, few prior studies have combined them for health risk analysis. In this study, road dust samples were collected from different geographical locations of Jinan (west area, WA; central area, CA; and east area, EA) to analyze the source-specific and bioaccessibility-based health risks of heavy metals. The mean concentrations of heavy metals in the three areas were CA > EA > WA, with Cd, Cu, Mn, Pb, and Zn exceeding their corresponding background values. A source analysis using a Positive Matrix Factorization (PMF) model showed that traffic emissions were the main source of heavy metals in the WA and CA, while industrial activities were the main source in the EA. The mean bioaccessibility of heavy metals extracted using the Solubility Bioaccessibility Research Consortium (SBRC) method followed the order of Cd (75.5%) > Zn (42.2%) > Mn (42.1%) > Pb (42.0%) > Cu (32.9%) > As (23.6%) > Ni (20.1%) > V (16.8%) > Cr (13.3%). According to the combined source analysis, traffic was the primary risk factor in the WA (54.5 and 58.3% of NCR and CR, respectively) and CA (61.8 and 51.2%), with solid waste being the main risk factor in the EA (41.9 and 51.3%). In oral bioaccessibility testing, lower non-carcinogenic (<1.0) and carcinogenic risks (<1 × 10−6) of heavy metals were observed than those based on the total metal content. More importantly, As (43.4%) was replaced by V (29.7%) as the main contributor to NCR. Source-specific and bioaccessibility-based health risk assessments can accurately identify priority pollutants and heavy metals in urban road dust that need to be controlled. This provides more effective and accurate urban environmental risk management recommendations for sustainable urban development and population health.

Health risk assessment of heavy metal(loid)s in road dust via dermal exposure pathway from a low latitude plateau provincial capital city: The importance of toxicological verification

The human health risk assessment through the dermal exposure of metal (loid)s in dust from low latitude and high geological background plateau cities was largely unknown. In this study, the road dust samples were harvested from a typical low-latitude plateau provincial capital city Kunming, Southwest China. The total concentration and dermal bioaccessibility of heavy metal (loid)s in road dust were determined, and their health risks as well as cytotoxicity on human skin keratinocytes were also assessed. The average concentrations of As (28.5 mg/kg), Cd (2.65 mg/kg), Mn (671 mg/kg), and Zn (511 mg/kg) exceeded the soil background values. Arsenic had the highest bioaccessibility after 2 h (3.79%), 8 h (4.24%), and 24 h (16.6%) extraction. The dermal pathway when bioaccessibility is considered has a higher hazard quotient than the conventional method using total metal(loid)s in the dust. In addition, toxicological verification suggested that the dust extracts suppressed the cell viability, increased the reactive oxygen species (ROS) level and DNA damage, and eventually activated the mitochondria-mediated apoptosis pathway, evidenced by the upregulation of Caspase-3/9, Bax, and Bak-1. Cadmium was positively correlated with the mRNA expression of Bax. Taken together, our data indicated that both dermal bioaccessibility and cytotoxicity should be considered for accurate human skin health risk assessment of heavy metal(loid)s in road dust, which may provide new insight for accurate human health risk assessment and environmental management.

Urban geochemistry of heavy metals in road dust from Cairo megacity, Egypt: enrichment, sources, contamination, and health risks

Traffic emissions, overpopulation, and poor urban planning have degraded the environmental quality of the Greater Cairo megacity. As road dust is considered the main sink of pollutants in urban environments, thirty road dust samples from six major roads were collected. ICP-OES was used to analyze the samples in order to determine the contamination grade using the pollution indices, decipher metal sources and geochemical associations using multivariate analysis, and evaluate the ecological and human health risks. The average contents of heavy metals were arranged in decreasing order: Fe (1181.12), Zn (201.36), Pb (66.10), Ni (32.42), Cu (26.07), Cr (26.00), Co (14.78), As (2.76), and Hg (0.93) mg/kg. The spatial pattern showed that new urban communities exhibited lower contamination levels compared to unplanned old districts, especially for traffic elements (Pb, Zn, and Cu). The highest Igeo mean value was observed for Hg (3.34) followed by Zn (1.34), Pb (1.24), Ni (0.10), As (− 0.19), Co (− 0.24), Cu (− 0.73), and Cr (− 1.05). Additionally, CF values indicated very high contamination levels for Pb and Zn, whereas the highest PLI value was observed at Ramses Street. All EF values were higher than 1.5, indicating the anthropogenic enrichment of metals. RI values classified Cairo as a region with considerable ecological risk, observing that Hg was the main contributor. Correlation analysis and PCA showed that Pb and Zn originated from vehicle exhaust, Hg, Cu, and As from domestic and industrial activities, and Fe and Co from natural origin. Cr and Ni exhibited potential carcinogenic risks for children through ingestion; conversely, the non-carcinogenic risks were within safe levels. As a result, the use of clean energy is recommended to mitigate the accumulation of heavy metals in road dust and to improve the quality of life.

Characteristics of heavy metals in road dust: An overview of South Korean cases

The urbanization and industrialization of our society necessitate the extension of road traffic systems. Road dust generated by road traffic is harmful to the human respiratory system. In particular, heavy metals adsorbed on road dust can pose substantial risks to human health owing to their toxicity, environmental longevity, and ability to accumulate in the human body. Although the evaluation of the concentration of heavy metals in road dust is essential for understanding their sources and risks to human health, there is a lack of comprehensive information on the heavy metal content in road dust in South Korea. In this review, sampling methods and analytical techniques for characterizing the contents of various heavy metals in road dust collected from different regions of South Korea are discussed. Cu, Zn, Cd, Pb, Ni, Cr, As, and Hg are the most frequently found heavy metals in road dust, and their concentrations are strongly associated with the sampling locations (e.g., industrial vs. residential sites and rural vs. urban areas) and particle size of the road dust. Road dust samples collected from more industrialized regions tend to contain more heavy metals. Further, smaller dust particles are likely apt to contain more heavy metals. The application of non-destructive analytical techniques is also necessary for the accurate characterization of heavy metals in road dust.

Sources and probabilistic ecological-health risks of heavy metals in road dust from urban areas in a typical industrial city

Urban road dust (URD) is a primary source of pollutants in urban environments. The contamination of heavy metals (HMs) in URD from urban area of Xingtai, a typical industrial city in China, was evaluated using enrichment factor, geoaccumulation index, and Nemerow integrated enrichment factor, along with Monte Carlo simulation (MCS). The HM sources in the URD were apportioned using positive matrix factorization (PMF). We employed a combination of PMF and MCS to estimate the probabilistic ecological-health risks of source-specific HMs in the URD and to identify priority sources and pollutants for HMs pollution control in the URD. Compared to the background values, the URD had elevated Pb, Co, Cr, Cu, Zn, and Ba concentrations. The overall pollution levels and ecological risks of the HMs were heavy and moderate, respectively, and were mainly caused by Co. The potential carcinogenic risks posed by HMs in URD to residents, and their non-carcinogenic risks to children, cannot be overlooked. The HMs in the URD originated mainly from industrial, mixed, and atmospheric deposition sources, accounting for 28.8, 30.8, and 40.4% of the total HMs, respectively. Mixed and industrial sources were priority sources, and Co and Cr were priority control HMs in the URD.

Pollution characteristics, associated risks, and possible sources of heavy metals in road dust collected from different areas of a metropolis in Vietnam.

Road dust samples were collected from different areas in Ho Chi Minh City (HCMC)-the largest city in Vietnam to explore pollution characteristics, ecological and human health risks, and sources of heavy metals (HMs). Results revealed the level of HMs found in the samples from residential and industrial zones of HCMC in the order of Mn > Zn > Cu > Cr > Pb > Ni > Co > As > Cd, Zn > Mn > Cu > Cr > Pb > Ni > Co > As > Cd. Due to the high enrichment of Cu, Zn in residential areas and Cu, Pb, Zn in industrial areas, the HM contamination in these areas remained moderate to severe. The findings also revealed a rising trend in the level of HMs in road dust from the east to the west of HCMC, and a heavy metal contamination hotspot in the west. In addition, industrial areas were more contaminated with HMs, posing greater associated risks than residential areas. Children living in urban areas of HCMC were found to be exposed to unacceptable health risks. Meanwhile, adults living in industrial areas face intolerable cancer risk. Among the nine HMs, Cd, Pb, and Cu posed the greatest ecological risk, while Cr and As were the main culprits behind health risks. HMs in road dust might derive from non-exhaust vehicular emissions, crustal materials, and industrial activities. The results suggested that industrial areas to the west of HCMC should focus more on reducing and controlling severe pollution of HMs.

Assessment of heavy metal pollution and preschool children health risk in urban street dusts from different functional areas in a typical industrial and mining city, NW China.

To assess the pollution characteristics and health risks associated with street dust exposure among preschool children in typical industrial and mining areas, we analyzed heavy metal concentrations of 20 urban street dusts in commercial area (CA), residential area (RA), scientific and educational area (SEA) and industrial and mining area (IMA) from Baiyin, NW China. The average concentrations of Cr, Mn, Ni, Cu, Zn, Cd, Pb, As and Hg were 614.96, 484.25, 1757.74, 6868.86, 893.19, 77.62, 1473.99, 15.01 and 0.59mg·kg-1, respectively. The ecological risk indexes for Cd, Cu and Hg were found as 20,075.20, 1425.07 and 1174.86, respectively, and the ecological risk was extremely high. The pollution load indexes (PLI) were > 1 for all four functional areas. The total hazard index (THI) for different functional areas were more than 1, and the main exposure pathway for children was ingestion route. Heavy metals in street dust of the IMA had the highest THI for children (43.88), and HI of Pb was being most significant (17.38). In addition, the carcinogenic risk to children via the respiratory route was acceptable. Furthermore, factor analysis and cluster analysis classified heavy metals into two groups, indicating common anthropogenic sources for Cr, Ni, Cu, Zn, Cd, Pb, As and Hg. In conclusion, urban street dusts from industrial and mining area of Baiyin, NW China were found polluted by heavy metals and the pollution would pose an obvious non-carcinogenic risk to preschool children.

Spatial Distribution and Pollution Level of Heavy Metals in Street Dust of the City of Suwałki (Poland).

This paper presents an analysis of the content and spatial distribution of heavy metals (HM) in street dust in Suwałki, a city located in northeastern Poland. The HM content of street dust was also evaluated using the geochemical index (Igeo), enrichment factor (EF), and contamination factor (CF), and local HM sources were identified using chemometric methods. The arithmetic averages of HM contents in dust arranged in the following order: Fe > Zn > Mn > Cu > Cr > Ni > Pb, were 11,692.80, 215.97, 194.78, 142.84, 63.59, 17.50, 17.04 mg∙kg-1, respectively. Higher values than the local background occurred for Cr, Cu, Ni, Zn and Pb. The values of Igeo, CF, and EF indicate that the highest pollution in dust is due to Zn and Cu. The spatial distribution of metals was evaluated using maps of HM content in road dust samples from Suwałki. The spatial distribution of HM showed areas with high contents of Cr, Cu, Ni, Zn and Pb located mainly in the central and eastern parts of the city. In these areas, high traffic volume, the presence of shopping centers, administrative buildings and bus stops dominate. Statistical models of multivariate analysis (FA) and cluster analysis (CA) identified two sources of HM. The first source of pollution was associated with local industrial activity and motor vehicle travel, and the second with natural sources.

Health risk assessment of heavy metals in road dust from the fourth-tier industrial city in central China based on Monte Carlo simulation and bioaccessibility

Health risks caused by heavy metal (HM) exposure in road dust has attracted extensive attention, but few studies have focused on the health risks of residents living in small- and medium-sized cities with rapid industrialization and urbanization. Thus, 140 road dust samples were collected across Anyang, a typical fourth-tier industrial city in central China, which were analysed for 10 different HMs (Mn, Zn, Pb, V, Cr, As, Cd, Ni, Cu and Co). Monte Carlo simulation and bioaccessibility were used to quantify the health risks of heavy metals comprehensively in road dust. Results revealed a remarkable accumulation of Mn, Zn, Pb, Cd and Cu. According to the Geo-accumulation index and potential ecological risk index, Cd was priority control pollutant. Moreover, 55.0% of the road dust samples reached heavily polluted level, and 52.86% of the samples were at high ecological risk levels. These results illustrated that HM contamination was serious and universal in the road dust of Anyang. The occurrences of HMs were allocated to traffic emissions, natural sources, industrial activities and agricultural activities with contribution rates of 35.4%, 6.0%, 41.6% and 17.0%, respectively. Except for Zn in the gastric phase, all other HMs had relatively low bioaccessibilities in the gastrointestinal system, usually less than 20%. The bioaccessibilities of most HMs were higher in the gastric phase, except for Cr, Ni and Cu, which remained higher in the intestinal phase. The non-carcinogenic risk and carcinogenic risk were remarkably reduced when considering the HM bioaccessibilities in the gastrointestinal system, especially for adults. The outcomes of this paper are valuable for understanding HM contamination in road dust and highlight the importance of risk assessment for populations living in the fourth- and fifth-tier cities.

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

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

Characteristics, Sources and Health Risk of Heavy Metals in Road Dust in the Typical County Town, Central China

In this study, to investigate the contamination characteristics and potential health implications of heavy metals in road dust of the typical county in central China, heavy metals (Cd, Co, Cr, Cu, Mn, Ni, V, Pb, Zn) in typical road dust with large traffic flow, in different functional areas of Yangxin County, were determined. The results of the geo-accumulation index (Igeo) showed that Co, Mn, Ni, and V were not polluted, while other heavy metals caused different degrees of pollution. According to principal component analysis (PCA), there were three main sources of heavy metals. The result of statistical analysis showed that heavy metal pollution in road dust mainly comes from traffic activities, industrial production activities, building pollution, and the natural environment. The carcinogenic and non-carcinogenic risks of children and adults were within the safe range, and hand–oral contact was the main exposure route of non-carcinogenic risks. The non-carcinogenic risk and carcinogenic effects of heavy metals in urban road dust were acceptable to children and adults. However, we should still pay attention to the impact of heavy metals on the ecological environment and human health.

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 (Igeo) and potential ecological risk assessment (PERI). Based on the Igeo 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.

Morphological characterization, hazardous metal contamination, source identification, and health risk assessment of the fine road dust from Dachang mining area, China.

Dachang mining area in China is known as "paradise for mineralogists" due to its most reserves of Sn, Sb, Pb, and Zn non-ferrous metal resources; thus, its evaluation for heavy metal assessment and consequent health risk is unavoidable. Sixty road dust samples were collected from study area to explore pollution level, ecological, and health risks from heavy metals and were analyzed by an inductively coupled plasma optical emission spectrometer and atomic fluorescence spectrometer. The results showed that average concentration of all the heavy metals in road dust in both mining and residential areas were remarkable higher than its corresponding background values, the former being more severe, except for Cr and Co. The morphological investigation showed that most of the particles were much less than 100μm illustrating fine part of the road dust samples. Based on integrated pollution indices, Cd, Sb, As, Zn, and Pb were extremely contaminated and exceeded hundred times of the maximum risk value. The health risk assessment revealed substantially higher carcinogenic and non-carcinogenic risks to children and adult. Highest non-carcinogenic risk resulted from arsenic in mining and residential area with HQing of 644.56 and 267.94 respectively (standard HQ ≥ 1) while carcinogenic risk to children (1.94E + 00) which greatly exceeded from the threshold value of (1.0E-4). Sb, Cd, and Pb also posed carcinogenic and non-carcinogenic risk in road dust which is caused by excessive mining activities and heavy vehicle movement in the study area.

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

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

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.

Comprehensive insight into heavy metal(loid)s in road dust from industrial and urban areas in northern Vietnam: concentrations, fractionation characteristics, and risk assessment

ABSTRACT Road dust samples were collected from 6 cities and provinces in northern Vietnam to evaluate contamination levels and distribution characteristics of 5 toxic elements, including Cu, Zn, Pb, Cd, and As. Total concentrations of 5 elements in road dust samples ranged from 18.4 to 470 (median 96.4) mg/kg, in declining order of Zn > Cu > Pb > As > Cd. Pollution levels in urban road dust from Hanoi (median 266; range 205–366 mg/kg) were generally higher than those measured in samples taken from other industrial areas (median 91.1; range 18.4–470 mg/kg). Our results showed that the emission of some heavy metals from urban areas with high population density and heavy traffic was comparable to or even higher than in manufacturing areas of electronic components, construction materials, and mining. The chemical fractions of heavy metals in road dust were also evaluated. More than 60% of heavy metals are present in the potential mobile phases, indicating that the anthropogenic metals are still in a relatively weakly bound form. These metals can be mobile and bioaccumulative, affecting ecosystems and humans. The geological accumulation indexes indicate moderate contamination of heavy metals in many locations of this study. Cd poses an ecological threat in several urban and industrial sites. There were no serious human health risks associated with heavy metals in road dust. However, relatively high levels of Cu and Pb in road dust imply a health risk for children living in some urban and industrial areas. Further monitoring and risk assessment studies on toxic elements in road dust should be conducted, especially in developing countries’ highly urbanised and industrialised areas.

Assessment of Heavy Metals in Road Dust of Behbahan City, Iran: Distribution, Sources and Health Risks

Introduction: Road dust is a group of solid particles that are presented in the urban areas and are originated from both natural and human-induced sources. This study aims to determine concentrations of heavy metals in urban dusts in Behbahan to identify their natural or anthropogenic sources. Materials and Methods: In this study, a total of 20 samples were collected from main roads with different land uses, including residential, industrial, and commercial areas in Behbahan city, Khuzestan province. Results: The results of mineralogy identification showed that calcite, dolomite, quartz, albite, and gypsum were the most identified minerals in dust samples. In addition, heavy metals of As, Co, Cr, Cu, Mn, Fe, Ni, Zn, Pb, Sb, U, Cd, Hg, and Mo were investigated in the collected settled road dust. The results indicated that the level of heavy metals, such as Co and Sb in the places with high traffic load were much higher than other areas. The highest Igeo value for Pb, Cu, and Sb were 1.39, 2.19, 2.46, respectively, suggesting that Pb, Cu, and Sb in the road dust were originated from the anthropogenic sources. Moreover, the results demonstrated that road dust may pose serious health threats to humans (both adults and children). Conclusion: In this study, the concentration of heavy metals in road dust of Behbahan was investigated. The concentration of heavy metals, such as Cu, Zn, Ni, As, Cr, Pb, U, and Fe in the road dust of the commercial section were much higher than other sections.

Heavy metals in road dust across China: occurrence, sources and health risk assessment.

We investigated the occurrence of Cd, Cr, Cu, Ni, Pb and Zn in 28 road dust samples collected across China from June to August, 2020. The mean concentrations of Cd, Cr, Cu, Ni, Pb and Zn were 3.16, 24.2, 27.4, 10.4, 49.8 and 608mg·kg- 1, respectively. The mean levels of Cd and Zn exceeded the Chinese background values by 32.6- and 8.2- fold. Cd, Ni mainly distributed in southern China, whereas Cu, Pb and Zn mainly distributed in central China. Higher concentrations of Cd, Cr, Cu and Pb were found in road dusts from urban areas than those from rural areas. Cu and Ni mainly came from natural sources; Pb and Cd mainly originated from industrial emissions and vehicle exhaust. Hand-mouth ingestion was the most common exposure pathway for both adults and children, followed by dermal contact and inhalation. Pb was found to be the highest risk element via ingestion. No significant non-carcinogenic risks and carcinogenic risks were found for local residents.