Receptor modeling and health risk assessment of suspended heavy metal particles in Tehran's District 21.

Suspended particles containing heavy metals from natural and anthropogenic sources are regarded as one of the world's most significant threats due to their potential adverse health effects. This research aimed to identify the sources of heavy metals in suspended particles in Tehran's District 21 and evaluate the health risks associated with exposure to these pollutants. Using a high-volume sampler, 50 samples were collected from five stations following ASTM D4096 and EPA standards. Per the EPA 2021 sampling schedule, sampling was conducted every six days from April 21, 2021, to April 20, 2022. Heavy metal concentration was measured using inductively coupled plasma-optical emission spectroscopy (ICP-OES). UNMIX was utilized for heavy metal source attribution. The integrated risk information system (IRIS) method was employed to estimate carcinogenic and noncarcinogenic risks. The average concentration of heavy metals over a year exhibited the following trend: Li < Ti < W < Pb < Sr < Mg < Fe < Zn < Cr < Al. Aluminum and lithium had the highest and lowest concentrations, 58.87 µg/m³ and 0.01 µg/m³, respectively. Light-duty vehicles, paved road dust, and aircraft emissions were estimated to contribute to 47%, 34%, and 18% of pollution, respectively. Finally, the health risk assessment results revealed that aluminum with an HQ value of 1.13e + 0.1 and lead with a CR value of 1.49e-0.5 pose significant noncarcinogenic and carcinogenic risks. [ABSTRACT FROM AUTHOR]