Risk assessment based on Cr, Mn, Co, Ni, Cu, Zn, Ba, Pb, and Sc contents in soils and blood Pb levels in children: Seasonable variations and Monte Carlo simulations

Abstract

Potentially toxic metals (PTMs) in soil pose threats and hazards to human health. Their seasonal variations were observed and thus their risks. However, limited research was conducted based on the seasonal variations of soil PTMs and children's blood lead levels (BLLs). In this study, seasonable variations of PTM risks (Cr, Mn, Co, Ni, Cu, Zn, Ba, and Pb) and 0–6 years old children's BLLs were investigated based on 534 Xi'an seasonable soils (spring, summer and winter) and Monte Carlo simulations. The results indicate that the distributions of PTMs and risks depended on seasonas. The highest Mn, Cr, Cu, and Pb contents appeared in the winter, which were 785, 148, 146, and 134 ​mg/kg, respectively. Pollution load index ranged 1.14–1.15, while ecological risk index was 30.6–30.9. Further, non-carcinogenic risk for Pb was 2.27–2.36 ​× ​10⁻², Zn was 8.10–8.73 ​× ​10⁻⁴ and Cu was 1.89–1.94 ​× ​10⁻². PTM contamination was slightly higher in the winter compared to spring and summer. Although PTMs posed mild pollution and acceptable risk, seasonal variations affected children's BLLs, particularly in the winter. The Zn, Cu, and Pb from automobile emissions were identified as the most significant source and priority contaminants in Xi'an, with blood Pb levels being slightly higher in winter at 3.24–3.39 μg/dL. This study highlights the importance of developing targeted strategies to mitigate Pb risks in urban areas, particularly addressing seasonal variations, to reduce children's BLLs effectively.