Spatial distribution and ecological risk of heavy metals in the sediments of the Luoyang section of the Luohe River
In order to clarify the distribution,risks,and sources of heavy metals in the sediments of the Luoyang section of the Luohe River,surface sediments were collected from 13 sites located in the upstream urban area,the main urban area,and the downstream urban area.Spatial distribution characteristics of heavy metals(Pb,Cd,Cr,Mo,Cu,and Zn)were ana-lyzed.The geoaccumulation index(Igeo),potential ecological risk index(RI),and principal component analysis were used to evaluate the pollution level,potential ecological risks,and identify the sources of heavy metals.The results showed that the av-erage mass fraction of heavy metal in the sediments,Pb(42.90 mg·kg-1),Cd(2.41 mg·kg-1),Cr(76.86 mg·kg-1),Mo(9.31 mg·kg-1),Cu(35.15 mg·kg-1)and Zn(145.60 mg·kg-1)were 1.7,14.2,1.1,13.7,1.5,and 2.2 times of the soil background values of heavy metals in Henan section of the Yellow River Basin,respectively.The contents of Pb,Cr and Cu in sediments in the upstream urban area were significantly higher than those in the downstream urban area,the contents of Cd,Mo,and Zn in the main urban area were significantly higher than those in the downstream urban area.There was no signif-icant difference between the upstream urban area and the main urban area.In the upstream urban area and the main urban area,the Cd pollution level at most sites reaches moderate to severe,while Mo pollution is moderate to severe,and the rest are mild or low.Source analysis indicates that Pb,Cd,Mo,Cu,and Zn mainly originate from anthropogenic sources,while Cr is primarily a natural source.The RI results showed that the sites in the upstream urban area have reached a strong ecological hazard level(Grade Ⅲ)or above,all sites in the main urban area have reached a very strong ecological risk level(Grade Ⅳ),while all sites in the downstream urban area were at a strong ecological risk level(Grade Ⅲ).Among them,Cd contributes the most(64.10％)to the RI,followed by Mo(32.67％).Luoyang City should focus on environmental risks potentially caused by the molybdenum industry and further reduce Cd pollution levels to mitigate heavy metal pollution and potential ecological risks in the Luohe River sediments.
万方数据
维普
