Nowadays, studies on monitoring and risk assessment of environmental pollutants, especially air pollutants, are necessary and inevitable. Among these pollutants, particulate matters are more important due to their ability to absorb other pollutants such as heavy metals and cause synergistic effect with them. The purpose of this study is to assess ecological risk, human health risk and identification of potential sources of heavy metals in PM2.5 and road dust in Isfahan City. For this purpose, the risk of 17 elements including iron (Fe), manganese (Mn), vanadium (V), chromium (Cr), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), molybdenum (Mo), palladium (Pd), silver (Ag), cadmium (Cd), tin (Sn), antimony (Sb), lanthanum (La) and lead (Pb) was determined in 40 different points of Isfahan City during four seasons (fall and winter 2017 and spring and summer 2018) using different ecological risk assessment indicators such as enrichment factor, geo-accumulation index, pollution index, ecological risk index, integrated pollution index, Nemro pollution index, polution load index, modified contamination degree, as well as overall ecological risk index. Then, the health risks of 6 elements including As, Pb, Cr, Cd, Co and Ni in both carcinogenic and non-carcinogenic states were eva‎luated using the human health risk assessment model. Furethermore, their potentials sources were investigated using statistical analyses including principal component, correlation and cluster analyses. Finally, land use regression method and interpolation methods were used for mapping the concentration of particulate matters of Isfahan City. In addition, road dust samples from four points of Jomhory Square, Azadi Square, Segzi and Gavkhooni Wetland were collected in summer (2017) and the concentration, risk and bioavailability of heavy metals in them were determined and eva‎luated through geochemical analysis. The results showed that the autumn was the critical season in terms of the concentration of particulate matters, concentration of heavy metals and the risk of metals in the particles. The elements of Cu, Mn, Ag, Cd, La and Sn had the highest risk levels. The elements of As, Pb, Cr and Cd were also identified as non-carcinogenic risk elements, among which Cd, Pb and As also crossed the carcinogenic threshold in some points. Bedies, the results of source identification revealed the existence of potential sources of traffic, metal smelting industries, brick and cement production, and petrochemical industries as the main potentially anthropogenic sources of heavy metals associated with particulate matters. The results of particulate matters zoning also confirmed the existence of a significant positive correlation between the concentration of particulate matters and industrial and high-traffic areas. The results of metal risk in road dust also showed that metals such as Cr and V had the highest risk at the stations. However, only Cr and Cd metals were at risk for human health. According to the obtained results, it is recommended to present and implement programs to reduce and prevent the release of metallic pollutants into the air to maintain the health of residents of Isfahan City.

محسن سليماني

محمد نعمتي ورنوسفادراني

نورالله ميرغفاري، سعيد پورمنافي