[Heavy Metal Content and Risk Assessment of Sediments and Soils in the Juma River Basin]

The sediment and soil in the Juma River channel pose a risk of pollution to the downstream ecological environment of Beijing and Xiong'an New Area. To address this issue, sediments and soil samples were collected along the river from the source to the Zhangfang outlet. The samples were further divided into three types:main stream sediment (29 samples), riverbank soil (27 samples), and farmland soil (26 samples). Enrichment factor analysis and the potential ecological risk index were employed to investigate the ecological risk. The results showed that the average concentrations of Cd, Hg, Pb, Zn, and Cu in the river sediment and soil in the study area were higher than those in the Baiyangdian Lake sediment and the surface soil of Hebei Province, whereas the concentrations of As, Cr, and Ni were relatively lower. The ranking of heavy metal pollution levels from high to low were Cd > Hg > Pb > Zn > Cu > Cr > Ni > As. The comprehensive ecological risk index showed that farmland soil and riverbank soil were mainly at a slight risk, followed by a moderate risk. The potential ecological risk of the main stream sediment was mainly moderate, severe, and extremely severe, accounting for 35.5%, 24.1%, and 24.1%, respectively, and the main contributing factors of the risk were Cd and Hg. The results of multivariate statistical analysis indicated that the main pollution sources of Cd, Pb, Zn, and Cu were industrial and mining activities. Cr, Ni, and As were mainly controlled by the weathering of the parent rock, and As was also influenced by agricultural activities. Hg was controlled by composite pollution sources such as industrial and mining activities, parent rock weathering, and atmospheric dust fall. Overall, the risk of heavy metal in the soil of the research area was generally at a slight level. However, there was a significant enrichment of Cd and other heavy metal in the sediment of the Taiyu-Sigezhuang-Pengtou River. This river section should be the focus of environmental monitoring, river dredging, and governance.