Concentration, sources and bioaccessibility-based risk assessment of heavy metals in air-borne PM2.5 in different landuses of Tehran

The present study investigated the concentration, spatial distribution, seasonal changes, potential sources, and bioaccessibility-based risk assessment of Particulate Matter 2.5 -bound heavy metals in seven regions of Tehran city with three different uses. A total of 64 samples were collected from high-traffic, low-traffic and industrial areas, whereby the concentration of Particulate Matter 2.5 -bound heavy metals was analyzed by Inductively Coupled Plasma device. Unmix 6 software was used to determine the source of pollution emission, in this study. Moreover, bioaccessibility-based risk assessment of ParticulateMatter 2.5 -bound heavy metals was done for inhabitants of Tehran city. The results indicated that the concentration of ∑heavy metal High-traffic, Low-traffic and Industrial areas was obtained as 2709.53 ± 172.91, 1981.136 ± 158.46, and 1047.28 ± 81.26 ng/m 3 , respectively. Based on Anmix analysis, 3 sources of heavy metals were found: source 1 mostly resulting from industrial sources, source 2 mainly from natural sources, and source 3 emanating from vehicles (both heavy and light). Bioaccessibility-based risk assessment also indicated that the risk of carcinogenicity of the studied metals exceeded the limit proposed by Environmental Protection Agency and World Health Organization (1 × 10 –4 ). Thus, in order to maintain the health of Tehran citizens, proper managerial strategies are required to control the concentration of these pollutants in the ambient air of Tehran. Graphical abstract