Airborne Particulates Pollution Level Characterization and Ecological Health Risk Assessment of Toxic Metals in Suburban Sfax, Southern Tunisia

The present study investigated the temporal variability of PM10 water-soluble and water-insoluble constituents (Ca ++ , Cl − , Na + , Mg ++ , K + , Fe (2;3)+ , PO 4 3− , NH 4 + , NO 3 − , SO 4 = , Pb, Zn, and Cu), as well as, the ecological and human health risks associated with toxic metals. It was conducted at the proximity of a traffic crossroad (≈22,580 vehicles per day) close to some kindergartens and schools (50–100 m) located in Suburban Sfax (Southern Tunisia), from January to October 2017. The results revealed the significant impact of multi-scale sources and meteorology. The source apportionment based on enrichment factors and principal component analysis highlighted three main origins: crustal (for Ca ++ , Mg ++ , Na + , K + , and Fe (2;3)+ ), marine (for Cl − ), and anthropogenic (for NO 3 − , NH 4 + , SO 4 = , PO 4 3− , Pb, Zn, and Cu). Computed I geo values of Pb, Zn, and Cu show that the most PM10 samples (80%) were ranged from 0 to 3. Based on Müller scale, they were moderately to strongly polluted. Eighteen percent of them were found to be strongly to extremely polluted. As regard m-ERM-Q values, the results showed that almost 50% of samples were characterized by a moderate ecological toxicity risk, and only 5% of them were distinguished by a high risk. Computed Hazard Index levels were shown to be significant for ingestion in the children’s group (4.09E+01) and for ingestion and dermal absorption in adults (8.49E+00 and 3.05E+02, respectively). These levels, well above 1, show a strong possibility of the chronic effects’ occurrence for the two age groups. The carcinogenic risk (CR) levels linked to Pb showing values ranged between 2.27E−06 and 7.60E−03 indicate moderate chances of developing any type of cancer due to lifetime exposure to this metal.