Source-oriented health risk assessment and priority control factor analysis of heavy metals in urban soil of Shanghai

The characteristics and ecological risks of heavy metal pollution in urban soils were comprehensively investigated, focusing on 224 typical industries undergoing redevelopment in Shanghai. The PMF (Positive Matrix Factorization) model was used to analyze the sources of soil heavy metals, while the HRA (Health Risk Assessment) model with Monte Carlo simulation assessed health risks to humans. Health risks under different pollution sources were explored, and priority control factors were identified. Results showed that, levels of most heavy metals exceeded Shanghai soil background values. Surface soil concentrations of Cd, Hg, Pb, Cu, Zn, and Ni exceeded the background values of Shanghai's soil to varying degrees, at 5.08, 5.40, 1.81, 1.95, 1.43, and 3.53 times, respectively. Four sources were identified: natural sources (22.23 %), mixed sources from the chemical industry and traffic (26.25 %), metal product sources (36.38 %), and pollution sources from electrical manufacturing and the integrated circuit industry (15.14 %). The HRA model indicated a tolerable carcinogenic risk for adults and children, with negligible non-carcinogenic risk. Potential risk was higher for children than for adult females, and higher for adult females than for adult males, with oral ingestion as the primary exposure pathway. Metal product sources and Ni were identified as primary control factors, suggesting intensified regional control. This study provides theoretical support for urban pollution prevention and control.