Prediction and risk assessment of five heavy metals in maize and peanut: A case study of Guangxi, China

To assess the contamination levels and health risk of cadmium (Cd), copper (Cu), mercury (Hg), lead (Pb), and zinc (Zn) to human beings, the concentrations of these heavy metals in soil were surveyed and the concentrations in maize and peanut grains were estimated by models. The geo-accumulation index (I geo) was calculated, and chronic daily intake (CDI), hazard quotient (HQ) and hazard index (HI) were estimated. Results indicated that the concentrations of Cd, Cu, Hg, Pb, and Zn in the soil samples exceeded the limit set by authorities in China. However, the concentrations in maize and peanut grains were rarely higher than the allowable concentrations suggested by the Ministry of Health of China (MHC). In accordance with geo-accumulation, these heavy metals in soil samples were polluted to different extents. Prediction models were developed to effectively assess the health risk of using TOC, Mn, pH, and CaO to human beings. Therefore, the concentrations of these heavy metals in the grains could be decreased by changing their levels in soil. The CDI, HQ, and HI were estimated by estimating concentrations of Cd, Cu, Pb, and Zn in maize grains, indicating that these metals exhibited a slight health risk to adult residents.