拒马河流域河流沉积物与土壤重金属含量及风险评价

拒马河流域河流沉积物与土壤存在污染下游北京市和雄安新区生态环境的风险,为此,沿源头至张坊出山口采集河流沉积物与土壤样品,将样品进一步分为干流底泥（29件）、河岸土壤（27件）和农田土壤（26件）这3种类型,采用富集因子法和潜在生态风险指数法开展了重金属富集特征与生态风险评价研究.结果表明,研究区河流沉积物与土壤Cd、Hg、Pb、Zn和Cu含量均值高于白洋淀底泥与河北省表层土壤含量均值,As、Cr和Ni含量则偏低.各重金属污染程度由高到低为：Cd>Hg>Pb>Zn>Cu>Cr>Ni>As,生态风险综合指数显示农田土壤和河岸土壤以轻微风险为主,其次为中度；干流底泥潜在生态风险则以中度、重度和严重为主,分别占比为35.5%、24.1%和24.1%,主要贡献因子为Cd和Hg.多元统计分析结果表明Cd、Pb、Zn和Cu主要污染源为工矿活动；Cr、Ni和As则主要由成土母岩风化控制,As还受农业活动等的影响；Hg则由工矿活动、母岩风化和大气降尘等复合污染源控制.总体上,研究区土壤重金属风险整体处于轻微等级,但台峪-司各庄-蓬头河段干流底泥中存在Cd等重金属明显富集的现象,环境监测、河道清淤与治理应以该河段为重点.

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.