Source identification of potentially hazardous elements and their relationships with soil properties in agricultural soil of the Pinggu district of Beijing, China: Multivariate statistical analysis and redundancy analysis

A total of 370 samples of agricultural soils were collected from the Pinggu district of Beijing to distinguish the natural and anthropogenic sources of potentially hazardous elements (PHEs) and to investigate the relationships between the PHEs and soil properties. The concentrations of potentially hazardous elements were detected in soil, and their median values (mg/kg) followed a decreasing order: V (81.4) > Zn (75.5) > Cr (68.4) > Ni (27.7) > Cu (27.1) > Co (12.6) > Cd (0.240) > Hg (0.096). The methods of multivariate statistical analysis were applied for source identification. It was determined that Co, Ni, Cr and V were primarily originated from the parent material of the soils, and that Cd, Cu, Zn and Hg were added primarily from agricultural cultivation. These results were confirmed by the method of spatial variability. Furthermore, the results of a linear model of redundancy analysis suggested that Co, Ni, Cr and V were closely associated with Fe2O3 and Al2O3, while Cd, Cu, Zn, Hg were associated with P, N and organic matter. In addition, the ecological risks were assessed for the evaluated elements in the soil of the study area. Our research provides comprehensive approaches to better understand the potential sources and the fate of contaminants in agricultural soils.