Iranian Journal of

Background and Objective: Non-biodegradation in nature and creation of adverse health effects in humans is important features of heavy metals. The main objective of this study was to determine the level of contamination, carcinogenic and non-carcinogenic risks of falling dust containing heavy metals on residents around the industrial areas of Ardakan. Another objective was to identify potential sources of heavy metal release into the environment.
Materials and Methods: In this cross-sectional analytical study, the falling dust was collected in summer around Tile and Ceramic, Khak-e-chini, sand and gravel and glass industries by installing 35 Inverted Frisbee traps with artificial grass cover. The concentration of Cd, Ba, Cu, Ni, Cr, Mn and V were measured by ICP-MS. Probable sources of the heavy metal of the dust were evaluated using Pearson correlation coefficient and cluster analysis. Ecological risk indices for determining the level of contamination and proposed relationships proposed by the US Environmental Protection Agency were used to assess the carcinogenic and non-carcinogenic risks.
Results: The highest and lowest mean concentrations of heavy metals were measured for Cd and Ba, respectively. The results of Pearson correlation analysis and cluster analysis revealed three anthropogenic and also natural sources for heavy metals of the falling dust. According to the Ecological Risk Potential Index, Cd in 45.10% of the samples was in a very high class and in 54.88% of the samples was a high class. Pollution class of the ecological risk index of all the heavy metals was medium to high. The carcinogenic risk of Cr and Ba in children and adults was estimated to be higher than 10^–4. In both age groups, the Hazard index for each metal was less than 1 and its sum was measured as 1.29 for children and 0.16 for adults.
Conclusion: Cd increases the ecological risk of the falling dust in the area. Ther heavy metal carcinogenic risk results showed that the concentrations of Cr and Ba were higher than standard. Also, the non-carcinogenic risk was higher in children than in adults.

Background and Objective: Urban traffic, while affecting human health, causes physiological and biochemical changes in plants. The aim of this study was to investigate the bioaccumulation potential of Pb and Cd and assess air pollution tolerance index for a number of plants grown high traffic areas of Yazd.

Materials and Methods: This cross-sectional, descriptive-analytical study was performed in both control and high traffic areas of Yazd city by random sampling of trees, shrub and herb species. After transferring the samples to laboratory, relative water content, pH of leaf extract, total chlorophyll and ascorbic acid content (the factors for calculating APTI) in plants were measured using standard methods. Furtheremore, Pb and Cd concentrations were measured to find their relation with APTI index in plants. All statistical analysis, including Kolmogorov–Smirnov test, ANOVA, Duncan test and Pearson correlation coefficient between the studied parameters, were performed in SPSS software version 22.

Results: The highest relative water content (84.73%) and ascorbic acid (5.98 mg/g) were measured in contaminated area for Canna indica and Rosa damascena, respectively. Also, the highest acidity (7.01) and total chlorophyll (1.48 mg/g) in the control area were measured for Verbena hybrida and Ligustrum vulgar, respectively. The highest air pollution tolerance values were recorded in Rosa damascena and Ligustrum vulgar. Moreover, the results obtained showed that APTI index was positively and significantly correlated to Pb, ascorbic acid and relative water content.

Conclusion: According to the classification of air pollution tolerance index, two species of Rosa damascena and Ligustrum vulgar exhibited moderately tolerant to traffic pollutant. Therefore, based on ecological requirements of these two species, they can be used to develop green spaces in high-traffic areas of Yazd.  This study showed that Pb increased physiological response of the studied plants, while the plants did not exhibit a significant physiological response to the Cd element. The results also showed that the relative water content and ascorbic acid were more important in the air pollution tolerance index than other factors.