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To assess the application of a receptor model on the identification of urban road dust pollution and associated human health risks by six heavy metal(loid)s (i.e., As, Cr, Cu, Ni, Pb, and Zn), the present study was carried out in Yazd City, a major city in Iran, that commonly experiences severe desert dust storms. The results indicate that, except for Ni, the mean concentration of all metal(loid)s was found to be higher than corresponding values in the upper continental crust with the highest ratio for Pb (3.8). Geogenic sources (i.e., dust storms and mining activities), vehicular emissions, and industrial emissions (iron, steel, tile, and ceramic factories) are responsible for heavy metal(loid)s pollution in urban road dust from the study area. According to the results of the PMF receptor model, geogenic sources are mainly characterized by Ni (65.8%), As (51.1%), and Zn (45.1%), whereas vehicular emissions are chiefly dominated by Pb (69.9%). With the contribution of 75.6% and 43.2%, Cr and As are the principal heavy metal(loid)s that originate from industrial emissions, respectively. Receptor model-based pollution assessment (RMB-MPI) highlighted those industrial emissions, followed by vehicular emissions and geogenic sources, are responsible for severe, high, and moderate pollution, respectively. The mean value of carcinogenic risk for Cr was found to be at the acceptable level for adults, whereas children are predicted to be at substantial risk of developing cancers due to exposure to Cr. Although the receptor model-based approach to estimate children's health risk (RMB-HHRA) due to exposure to Cr showed an acceptable level of risk from geogenic, vehicular, and industrial sources, the cumulative concentrations of Cr from all three source types lead to elevated cancer risk in children. [ABSTRACT FROM AUTHOR]

Urban soil pollution with heavy metals is one of the environmental problems in recent years, especially in industrial cities. The aim of this study is to evaluate the role of geogenic and anthropogenic sources in the urban soil pollution in Yazd, Iran. For this purpose, 30 top-soil (0–10 cm) samples from Yazd within an area of 136.37 Km2 and population of nearly 656 thousand are collected, and the concentration of heavy elements is measured. To evaluate factors affecting the concentration of heavy elements in urban soils and determine their possible sources, Multivariate statistical analysis, including correlation coefficient, principal components analysis (PCA) and cluster analysis (CA) are performed. Enrichment Factor (EF), Geo-accumulation index (Igeo), and Modified potential ecological Risk Index (MRI) are used to assess the level and extension of contamination. Results of this study suggest that As, Cd, Pb and Zn are affected by anthropogenic source, while the concentrations of Fe, Mn, Ni, Cr, Co, Cu and Cs have come from mostly natural geologic sources. As, Cd and Pb are considerably enriched in the area, provided moderately enriched for the elements Mn, Zn and Cu. However, the other heavy elements show minimal enrichment. Igeo reveal that Co, Cr, Cs, Cu, Fe, Mn, Zn and Ni with negative values are unpolluted, Pb posed unpolluted to moderately polluted, and As and Cd represent high polluted. Based on the results of the ecological risk factor, the heavy metals of Mn, Ni, Cr, Zn and Cu have a low ecological risk level. More specifically, we find that Pb shows a moderated ecological risk in 39% of the urban soil in the studied area. As and Cd with respectively 100 and 72% contribution have considerable and very high ecological risk. According to the results of MRI, the area is in a very high ecological risk level, and appropriate management practice is essential to reduce the pollution of heavy elements in this area. [ABSTRACT FROM AUTHOR]

Heavy metal pollution significantly reduces the quality of the environment and threatens human health, especially in industrial cities. This study investigated toxic metals concentrations, pollution levels and human health risks assessment of urban soils in Yazd City, as an industrial city in center of Iran. Soil surface samples (0–10 cm) were collected from 30 points in the area for geochemical analysis. The concentrations of heavy metals were determined using an inductively coupled plasma mass spectrometry (ICP-MS). The values of the mean concentrations of toxic metals (mg kg−1) in the urban soils decrease in the order of Zn (83.9) > Pb (34.5) > Cr (32.6) > Cu (23.5) > Ni (23.4) > As (5.86) > Co (4.86) > Cd (0.27). The mean concentration of Zn, Pb, As and Cd elements was higher than the background and the crust values. A pollution assessment by Geo-accumulation Index (Igeo), Pollution Index (PI), Contamination Degree (CD), the Integrated Pollution Index (IPI), the Pollution Load Index (PLI) and Integrated Nemerow Pollution Index (INPI) showed that As, Cd and Pb were moderately enriched and the study area polluted considerably by these toxic metals. Based on PI results, 88.9% of the urban soil samples highly polluted by As. Overall, the quality of the urban soil in Yazd City is clearly affected by toxic metals. Due to the prevailing wind direction, the route of the north–south highway of Iran and the population density and traffic of the northwestern and southern areas of the study area were found the highest level of pollution indicators (IPI > 1.8; LPI > 1.3; CD > 15 and INPI > 4.3). The results of Pearson correlation analysis indicated that all pollution evaluation indicators were influenced by As and Cu, and showed high significant correlation with these two elements, while neither of them had a significant relationship with Pb and was found also a weak link statistically with Cd. Health risk assessment of toxic metals has been performed in both carcinogenic and non-carcinogenic sectors. The results indicate that oral intake is the main pathway that toxic metals can harm human health for both the child and adults. The carcinogenic risks (RI) of adults and child by toxic metals were as follows: Ni > Pb > Cr > As > Cd. Hazard quotients (HQ) and hazard index (HI) values for child also were higher than these for adults. Generally, the results demonstrated that the potential carcinogenic health risks for adults of toxic metals were in an acceptable range in study area, whereas for Cr, Ni and Pb with RI > 10–4, the risk of cancer in child probably increases. [ABSTRACT FROM AUTHOR]