انجمن مخاطره شناسی ایران مدیریت مخاطرات محیطی 2423-415X 8 4 2021 12 22 Identification of effective factors concentration of heavy metals in the dust existing in the air of Tehran metropolis عوامل موثردر ایجاد غلظت فلزات سنگین در گردوغبار هوای کلانشهر تهران و مخاطرات آن 321 335 85881 10.22059/jhsci.2021.329792.673 FA فاطمه ارسلانی دکتری مخاطرات آب و هوا، دانشگاه خوارزمی، تهران، ایران بهلول علیجانی استاد گروه اقلیم شناسی، دانشگاه خوارزمی، تهران، ایران Journal Article 2021 08 31 Introduction In large and industrial cities, thousands of heavy metal particles are released into the environment [2]. These heavy metal particles are released by attaching to dust particles on a large scale [3]. It is important to study heavy metal concentrations in the dust falling due to the threats for human health [1, 4, 5]. Dust originates from both natural and human sources. Studies have been conducted to investigate the sources of heavy metal emissions in street dust with cluster analysis [CA] and principal component analysis [PCA] methods. The metropolis of Tehran has a population of over eight million people, that facing a severe air pollution problem. Therefore, the purpose of the present study was to identify the factors of increasing the heavy metal concentrations (Al, As, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Se, Si, V, Zn) in the dust falling of Tehran city.  Materials and methods Dust fallout samples were collected with using Marble Dust Collector (MDCO) from 28 different locations across the city of Tehran, during winter of 2017. XRF analysis used to identify and determine the concentration of heavy metals. The Principal Component Analysis (PCA) method were summarized 15 heavy elements studied into three factors. The kriging interpolation method was used to determine the role of each factor in the study area. In the next step, the extracted factors were grouped based on factor scores, by statistical method of cluster analysis. Discussion and Results The results of the Principal Component Analysis (PCA) showed the existence of three factors: natural, human and combination of natural and human factors which increasing the concentration of heavy metals in the dust of Tehran metropolis. Factor 1: Aluminum, chromium, iron, magnesium, manganese, nickel, silicon, and vanadium have the same emission source. These factors are not affected by human activities but have natural origin. Therefore, this category was called the natural factor. Factor 2: Arsenic, cadmium, copper, lead, and selenium have the same emission source. Probably, human factors have role in increasing these elements in the dust falling.  Therefore, this category was called the human factor. Factor 3: Cobalt and zinc have the same emission source. This factor is combination of both natural and human factors. Based on the extracted factors and with using method of Cluster Analysis (CA), the stations in Tehran were classified into four clusters as follows: The First group: Forest and Range Organization of IRAN, Dadman Blvd, Pole Gisha, Arash Blvd, Majidiyeh Shomali, Janatabad, Shahre Ziba, Pole Kan, Motahhari, Narmak, Hashemi, Tehransar. These stations are located in the northern and western regions of Tehran. The second group: Afsaria station is located in the southeast of Tehran. This station has the highest concentration of heavy metal in dust falling. The Third group: Velenjak station is located in north of Tehran. The heavy metal concentrations in dust falling are higher than other groups in human resources. The Fourth group: Enghelab, Darvaze Dolat, Imam Hossein Square, Nawab, Si-e-tir, Komeil Gharbi, Tehranno, Piroozi, Nazi Abad and Shahr-e-rey are located in this cluster. These stations are located in the central, eastern and southern regions of Tehran. The concentration of heavy metals in these regions are high. Conclusion Heavy metals in dust are an important component of urban pollution. The harmful effects of heavy elements on human health have been proven in different ways. Considering the population of Tehran metropolis, the results of this research are very important for developing management approaches to create a healthier environment. The results showed that the pollution of dust falling into heavy metal with human origin in the northern and western regions of Tehran is less than other regions and in the southeast of Tehran is more than other regions. results indicated that population density, traffic and traffic volume, industries and mines, topographic pattern, vegetation pattern, prevailing wind pattern and air stability are effective in the concentration of heavy elements in Tehran dust falling. فلزات سنگین موجود در گرد و غبار هوا، جزء خطرناک­ترین آلاینده­هایی است که سلامتی انسان و محیط را مورد تهدید جدی قرار می­دهد. هدف پژوهش حاضر شناسایی عوامل افزایش غلظت فلزات سنگین (Al, As, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Se, Si, V, Zn) موجود در گردوغبار ریزشی هوای کلانشهر تهران و بررسی وضعیت آلودگی و پراکندگی آن روی ایستگاه­های مورد مطالعه است. بدین منظور 28 نمونه غبار ریزشی در زمستان 1396 از مناطق مختلف تهران جمع­آوری شد. آنالیز XRF غلظت عناصر سنگین موجود در آن را مشخص کرد. با روش تجزیه مؤلفه اصلی(PCA)، 15 عنصر سنگین مورد مطالعه، در سه عامل خلاصه شد. سپس عامل­های استخراج شده، با روش آماری تجزیه خوشه­ای(CA)  و با استفاده از روش ادغام وارد گروهبندی شد. جهت تعیین پراکندگی فضایی هر عامل در منطقه­ی مورد مطالعه، از روش درون­یابی کریجینگ در GIS استفاده شد. نتایج وجود سه عامل طبیعی، انسانی و ترکیبی از عامل­های طبیعی و انسانی را در افزایش غلظت فلزات سنگین در غبار ریزشی کلانشهر تهران نشان داد. عوامل طبیعی در شمال تهران، عوامل انسانی در شرق تهران و ترکیبی از عامل­های طبیعی و انسانی در جنوب تهران در آلودگی غبار ریزشی به فلزات سنگین نقش بیشتری داشت. تحلیل نتایج نشان داد تراکم جمعیت، ترافیک و حجم تردد، بخصوص تردد خودروهای سنگین و دیزلی، صنایع و معادن، الگوی توپوگرافی، الگوی پوشش گیاهی، الگوی باد غالب و وضعیت پایداری هوا در غلظت عناصر سنگین موجود در غبار ریزشی تهران نقش دارد. بنابراین برای مدیریت و کنترل آلودگی، گسترش و بهینه­سازی حمل و نقل عمومی و گسترش فرهنگ استفاده از آن (بخصوص مترو) مخصوصاً در نیمه­ی شرقی تهران و ایجاد پوشش گیاهی بیشتر و مرتفع­تر در مناطق حاشیه غربی و جنوبی شهر تهران پیشنهاد می­گردد. https://jhsci.ut.ac.ir/article_85881_a25e0ac9b5a456cfd20380130a4ad547.pdf