Pollution Characteristics, Spatial Distribution, and Health Risk Assessment of Soil Heavy Metal(loid)s in Panxi District, Southwest China: A Typical Industrial City

This study collected 49 topsoil samples in agricultural soil from Panxi district (Sichuan, China), investigating the contamination status and probabilistic health risk of their heavy metal(loid)s (HMs). The average concentrations (mg/kg) of As, Cd, Cr, Cu, Ni, Pb and Zn were 18.18, 1.66, 294.05, 143.37, 70.18, 31.70 and 139.18, respectively. The pollution index (Pi) of the seven HMs were in the descending order of Cd > Cr > Cu > As > Zn > Ni > Pb, and the comprehensive Nemeiro risk index (PN) was 2.67, indicating that the study area was a moderate pollution by HMs. Meanwhile, Cd showed major contribution to the soil pollution among these HMs. The spatial distribution of HMs revealed that the southwestern part of the study area was the contamination hotspots. The hazard index (Hi) for children and adults were 1.621 and 0.346, respectively, and the total non-carcinogenic risk for children exceeded the threshold of 1. The carcinogenic risks associated with Cr (adults:, children:) and Ni (adults:) far exceeded the safe level of 1E-04; Monte Carlo simulations showed that humans locating in the study area suffered from a relatively significant carcinogenic risk; and the children were at higher risk than the adults. Among the three exposure pathways (ingestion, inhalation, and dermal contact), the ingestion was the most important way for HMs to harm human health. Overall, this study provides a scientific basis for both controlling HMs contamination and reducing the potential health risks in studied soils.