[Risk Assessment of Soil Heavy Metal Sources in the Lower Reaches of the Jinling River Based on PMF Model and Geodetector].

Abstract

To understand the pollution characteristics and sources of heavy metals in the soil of the lower reaches of the Jinling River, 41 samples of surface soil in the lower reaches of the Jinling River were collected, and the contents of eight heavy metals （Cr, Mn, Ni, Cu, Zn, As, Cd, and Pb） were determined by high-precision X-ray fluorescence spectrometer （HDXRF）. Correlation analysis and positive matrix factorization model （PMF） were used to analyze the sources of heavy metals in the soil. The potential ecological risk assessment model based on source was used to analyze the potential ecological risk under different pollution sources, and the influencing factors of ecological risk of each pollution source were analyzed by means of geographical detector. The results showed that： ① The average values of eight heavy metal elements in soil were lower than the risk screening values of soil pollution but higher than the soil background values of Shaanxi Province. The spatial variability of Zn, Cd, and Pb was large, which was mainly affected by human activities. ② The heavy metals in the soil of the study area were mainly from industrial sources, traffic sources, natural sources, and agricultural-industrial mixed sources, and the contribution rates of each pollution source were 16.51%, 23.68%, 51.08%, and 8.73%, respectively. Based on the source-based potential ecological risk assessment, the potential ecological risk index （RI） of industrial sources, traffic sources, natural sources, and agricultural-industrial mixed sources were 34.11, 85.03, 16.76, and 21.19, respectively. Cd was the priority control element, and traffic sources were the priority control sources. ③ The distance from key enterprises, the distance from highway, sand content, and land use type were the main influencing factors of the industrial source, traffic source, natural source, and agricultural-industrial mixed sources, respectively. The results of this study can provide scientific basis for environmental management and pollution control of heavy metals in soil.