Heavy metals in urban and peri-urban soils of a heavily-populated and industrialized city: Assessment of ecological risks and human health repercussions

Increasing levels of heavy metals in soil have become a serious concern for human health because they can be easily transferred into the human body through contaminated food web. It is imperative to evaluate pollution levels, origin and ecological risks of heavy metals. The geoaccumaualtion (Igeo), contamination factor (CF), pollution load index (PLI) and human health risk were estimated to determine the soil pollution in Faisalabad, a heavily-populated and industrialized city of Pakistan. The maximum CF (1.58) and PLI (1.22) values were estimated for Cd and Pb, respectively, and maximum Igeo (-0.19) value was observed for Cd. Correlation analysis and principal component analysis suggested that common industrial sources for Cd and Pb were identified in the study sites. It clearly indicates that the significant levels of heavy metals pollution arise from local industries, busy commercial centers and heavy traffic load in the last few decades in heavily-populated and industrialized city. Further, soil heavy metals concentration were used to evaluate the human health risk such as chronic or non-carcinogenic including hazard indexes HIexP (ingestion, inhalation and dermal and carcinogenic) and cancer risk (CR). The HIexP values of Pb (10.30) and Cd (4.56) were found above the permissible limit (HI = 1) for children. The CR due to carcinogenic metals (Co, Cr and Cd) are within the safe limit (1E-06 to 1E-04). However, CR was comparatively higher in adults as compared to children. The results from the current investigation can help to develop a sustainable strategy in the study region to minimize the entry of heavy metals in food chain through source identification and pollution abatement techniques.