Identification source and human health risk assessment of potentially toxic metal in soil samples around karst watershed of Pangkajene, Indonesia

This study focuses on the health risks caused by potentially toxic metal (Cd, Cr, Hg, Ni, and Pb) contamination in soil. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) were used to identify the source of heavy metal. While non-carcinogenic and carcinogenic risks were determined using deterministic (USEPA's human health risk assessment methods) and probabilistic methods (Monte Carlo Simulation model), respectively. The mean concentration of heavy metal increased in the order of Cd < Ni < Pb < Hg < Cr. PCA, HCA, and spatial distribution demonstrated that Pb and Ni may be derived from anthropogenic activities, whereas Cr and Hg were mostly derived from natural sources. Adults and children were relatively safe from non-carcinogenic risk except for children living near mining and cement factories (THI > 1). The total average cancer risk of adults and children was 2E-03 and 7E-04, respectively. This indicates that both adults and children were at high risk of developing cancer in the future (TCR > 1E-04). Based on the sensitivity analysis, Cr concentration, exposure frequency, and exposure duration were the most influential factors to cancer risk. Therefore, we must implement integrated risk management, which includes reducing Cr concentration in soil, and educating people to avoid soil contact, and implementing good personal hygiene. The recommended concentration of Cr in the soil was 20 mg/kg.