University of Tehran Journal of Environmental Studies 1025-8620 50 4 2025 02 28 Spatiotemporal variations of potentially toxic elements in dry deposition of Hamedan Megacity, west of Iran; levels and ecological risk Spatiotemporal variations of potentially toxic elements in dry deposition of Hamedan Megacity, west of Iran; levels and ecological risk 477 500 100780 10.22059/jes.2025.378315.1008511 FA Bijan Haghi Department of the Environment, College of Basic Sciences, Hamedan Branch, Islamic Azad University, Hamedan, Iran 0009-0004-2827-8431 Mehrdad Cheraghi Department of the Environment, College of Basic Sciences, Hamedan Branch, Islamic Azad University, Hamedan, Iran 0000-0001-9917-805X Soheil Sobhan Ardakani Department of the Environment, College of Basic Sciences, Hamedan Branch, Islamic Azad University, Hamedan, Iran 0000-0002-6038-0514 Bahareh Lorestani Department of the Environment, College of Basic Sciences, Hamedan Branch, Islamic Azad University, Hamedan, Iran 0000-0001-5016-8651 Maryam Kiani Sadr Department of the Environment, College of Basic Sciences, Hamedan Branch, Islamic Azad University, Hamedan, Iran 0000-0002-9410-8332 Journal Article 2024 07 12 Objective: Airborne particulate matter, especially the fine particles, is known as a potential source of potentially toxic elements (PTEs) for people living in urban communities and can lead to adverse effects such as adhering to the surface of pulmonary epithelial cells and lung alveoli, acute inflammatory reaction on human health through inhalation, oral, and dermal contact routes, and also oxidative stress. Therefore, concern about the quality of dust and atmospheric depositions is vital. Since the similar studies in terms of the ecological risk assessment of arsenic (As), cadmium (Cd), chromium (Cr), manganese (Mn), and lead (Pb) in atmospheric dry deposition have not been previously conducted in the city of Hamedan, this study was performed to assess the spatiotemporal variations and ecological risks of PTEs in the dry deposition of Hamedan Megacity in 2023. Method: In this descriptive cross-sectional study, a total of 144 dry deposition samples were collected from 12 sampling sites across four seasons. Following sample preparation and acid digestion, the concentrations of As, Cd, Cr, Mn, and Pb were determined using inductively coupled plasma-optical emission spectroscopy (ICP-OES). Additionally, various indices, including the pollution index (PI), integrated pollution index (IPI), ecological risk (Er), and the comprehensive potential ecological risk index (RI), were calculated to assess the pollution and ecological risks associated with these elements. Statistical analyses of the results were performed using SPSS statistical software. Results: The results of determining the content of the elements revealed the significant impact of human activities, particularly those of industrial origin and traffic. The PI values indicated that the pollution levels of As, Cd, Cr, Mn, and Pb ranged from "low" to "high." Furthermore, the average IPI value of 1.73 suggested "moderate" pollution conditions in the study area. Ecological risk assessments demonstrated that in all sampled regions and seasons, the Er values for As, Cr, Mn, and Pb were categorized as "low risk," whereas Cd exhibited a "moderate" to "high" risk level. Additionally, the average RI value of 113 indicated a "moderate" level of hazard posed by dry deposition in the studied area. Notably, Cd, accounting for 68.3% of the ecological risk, had the most significant contribution to the overall ecological risk assessment. Conclusions: In conclusion, it is recommended to conduct regular monitoring the concentrations of PTEs and perform ecological and health risk assessments of contaminated dry deposition. Such measures are essential for safeguarding the health of both the environment and the residents. Objective: Airborne particulate matter, especially the fine particles, is known as a potential source of potentially toxic elements (PTEs) for people living in urban communities and can lead to adverse effects such as adhering to the surface of pulmonary epithelial cells and lung alveoli, acute inflammatory reaction on human health through inhalation, oral, and dermal contact routes, and also oxidative stress. Therefore, concern about the quality of dust and atmospheric depositions is vital. Since the similar studies in terms of the ecological risk assessment of arsenic (As), cadmium (Cd), chromium (Cr), manganese (Mn), and lead (Pb) in atmospheric dry deposition have not been previously conducted in the city of Hamedan, this study was performed to assess the spatiotemporal variations and ecological risks of PTEs in the dry deposition of Hamedan Megacity in 2023. Method: In this descriptive cross-sectional study, a total of 144 dry deposition samples were collected from 12 sampling sites across four seasons. Following sample preparation and acid digestion, the concentrations of As, Cd, Cr, Mn, and Pb were determined using inductively coupled plasma-optical emission spectroscopy (ICP-OES). Additionally, various indices, including the pollution index (PI), integrated pollution index (IPI), ecological risk (Er), and the comprehensive potential ecological risk index (RI), were calculated to assess the pollution and ecological risks associated with these elements. Statistical analyses of the results were performed using SPSS statistical software. Results: The results of determining the content of the elements revealed the significant impact of human activities, particularly those of industrial origin and traffic. The PI values indicated that the pollution levels of As, Cd, Cr, Mn, and Pb ranged from "low" to "high." Furthermore, the average IPI value of 1.73 suggested "moderate" pollution conditions in the study area. Ecological risk assessments demonstrated that in all sampled regions and seasons, the Er values for As, Cr, Mn, and Pb were categorized as "low risk," whereas Cd exhibited a "moderate" to "high" risk level. Additionally, the average RI value of 113 indicated a "moderate" level of hazard posed by dry deposition in the studied area. Notably, Cd, accounting for 68.3% of the ecological risk, had the most significant contribution to the overall ecological risk assessment. Conclusions: In conclusion, it is recommended to conduct regular monitoring the concentrations of PTEs and perform ecological and health risk assessments of contaminated dry deposition. Such measures are essential for safeguarding the health of both the environment and the residents.

https://jes.ut.ac.ir/article_100780_fdc6dbc601a35260511baa6fe53dcddf.pdf