Priority control of potentially toxic elements in urban park soils through integrated source apportionment and health...

Accelerating urbanization has rendered contamination of urban soils by potentially toxic elements (PTEs) a critical threat to public health and ecological security. This study investigated park greenspaces in the central urban area of Chengdu, systematically assessing the spatial distribution, source contributions, and ecological health risks of seven PTEs (Cd, Hg, As, Pb, Cu, Zn, and Cr). Surface soil samples collected from 13 districts of Chengdu were analyzed for PTEs by ICP-MS and AFS, followed by source apportionment using positive matrix factorization (PMF) and health risk assessment coupled with Monte Carlo simulations. The results revealed that the concentrations of most elements exceeded the Sichuan soil background values (e.g., Cd = 0.33 versus 0.1 mg/kg; Hg = 0.19 vs. 0.07 mg/kg). PMF analysis indicated that PTEs were primarily derived from industrial activities (34.1%), traffic emissions (32.1%), natural sources (24.5%), and atmospheric deposition (9.3%). Health risk assessment, coupled with Monte Carlo simulations, revealed that non-carcinogenic risks were negligible for both adults and children, while carcinogenic risks were within acceptable range for adults. However, the probability of carcinogenic risk exceeding the acceptable threshold reached 44.8% for children, with As and Cd identified as the dominant contributors and ingestion as the primary exposure pathway. Integrated source-risk analysis, As, Cd, and Cu are recommended as priority control elements, with industrial and traffic-related sources identified as key targets for management. These findings serve as a scientific foundation for targeted management of soil pollution in urban greenspaces and the protection of public health.