Abstract:
Three cities in Guangdong Province, Shenzhen, Huizhou and Zhaoqing, were selected as the research area, and total 181 soil samples from 36 city parks were collected to determine the contents of eight heavy metals, including Pb, Cd, Cr, Zn, Mn, Ni, Cu, and V. The primary sources of soil heavy metals were analyzed by the Absolute Principal Component Scores-Multiple Linear Regression (APCS-MLR) model and the Positive Matrix Factorization (PMF) model, and the risk assessment was conducted employing a refined version of the Potential Ecological Risk Index (NIRI) alongside the Health Risk Assessment model, while the four models were combined to identify priority control factors. Our results showed that the average values of two heavy metals, Pb (46.91 mg/kg) and Cu (41.00 mg/kg), were higher than the background values for urban soils in China in the urban park soils of Shenzhen, and the sources were traffic sources and industrial sources, respectively; only the mean value of the element Pb (30.42 mg/kg) in the soil of the urban park in Huizhou was higher than the background value of Guangdong Province, and the main source was the traffic source; Zhaoqing park soil mean values of Cd (0.74 mg/kg), Cu (59.04 mg/kg), Pb (88.13 mg/kg) and Zn (104.52 mg/kg) exceeded the background values, with the main sources being a mixture of agricultural and traffic sources. The potential ecological risk associated with soil heavy metals was present in all three city parks, with Zhaoqing Park exhibiting the highest level of potential ecological risk. The non-carcinogenic health risks posed by soil heavy metals in urban parks are deemed acceptable for both adults and children. Industrial activities are the chief contributors, with cadmium (Cd and Cu) recognized as the primary element requiring regulation. The present study provides data support and theoretical reference for future related research, and is of great practical significance for safeguarding the safety of urban ecological environment and the prevention and control of residents' health.