A synthetic health risk assessment based on geochemical equilibrium simulation and grid spatial interpolation for zinc (II) species.

Soil heavy metal pollution has become a global issue involving environmental safety and human health risks. This paper quantified the sources of heavy metals by positive matrix factorization (PMF) model and explored the spatial distribution of heavy metals by means of grid scales, with an industrial site as the study area in Suzhou. The PMF identified four pollution sources of heavy metal in soil, and the quantitative results revealed that industrial activities (33.5%) contributed the most to heavy metals, followed by soil parent materials (30.8%) and agricultural activities (19.7%). Zinc (Zn) was screened out as the targeted metal (TM) through the potential ecological risk assessment, the metal species of which was simulated by the geochemical software PHREEQC. This research aimed to determine the dominant metal species of TM with high-risk levels to realize the transformation of toxic metal species. Herein, according to the morphological evolution of metal species, the activity and concentration of the Zn ion species were obtained for both carcinogenic and non-carcinogenic risk assessment. The evaluation of the optimized human health risk demonstrated that the associated health risk of Zn (II) ions depended predominantly on its metal speciation. Overall, the optimized carcinogenic and non-carcinogenic risk value of Zn2S32- for adults was 2.01E-04 and for children was 1.31, resulting in corresponding hazardous risk to humans, which accounted for high-risk levels of 61.5% and 58.5% for adults and children, respectively. The OHRA method can provide a reference for the decision-making of soil heavy metal pollution and remediation for specific heavy metals in polluted areas.