Health risk assessment associated to heavy metal pollution levels in Mediterranean environment soils: a case study in the watershed of Sebkhet Ariana, Tunisia

We measured the concentrations of 9 heavy metals (Fe, Cd, Hg, Pb, Zn, Co, Cr, Cu, Ni) in the soils collected in the watershed of Sebkhet Ariana (Tunisia) and assessed health risks for residential adults and children. Also, we assessed their potential sources, contamination status, and ecological risks using pollution indicators such as the enrichment factor (EF), geoaccumulation index ( I geo ), contamination factor (CF), pollution load index (PLI), ecological risk (RI), hazard index (HI), and carcinogenic risk index (CRI) to both children and adults. Heavy metal concentrations followed the order Fe > Zn > Pb > Cr > Ni > Cu > Co > Cd > Hg. Geoaccumulation index, contamination factor, and enrichment factor results indicated that watershed of Sebkhet Ariana was polluted with Cd, Hg, and Pb due to use of pesticides and fertilizers and industrial wastewater reuse. Also, the study region had “high potential ecological risk” for Cd, whereas “low potential ecological risk” for the other heavy metals. Factor and hierarchical cluster analyses revealed that Ni, Hg, and Cu were from anthropogenic sources; Cd, Cr, and Co from both anthropogenic and natural sources; while other heavy metals from natural sources. The hazard index and the carcinogenic risk of HMs in adults’ group revealed an acceptable level; however, children’s group faced a great chance of carcinogenic risk by Cr and Ni moreover non-carcinogenic risk due to high level of Co.