Pollution Characteristics and Ecological Risk Assessment of Heavy Metals in the Sediments of Shangyou Reservoir in Songming County
Taking the sediments of Shangyou reservoir of Songming County as the research object,the spatial distribution characteristics of eight heavy metals(Zn,Cu,Cr,Ni,Pb,As,Cd,Hg)in different areas of the reservoir tail,reservoir and lock dam were analyzed,and the pollution characteristics and ecological risk level of heavy metals were evaluated using the ground accumulation index method and potential ecological risk index method.The results showed that:Cu、Zn、Cr、Cd、Ni、Pband Hg indicated different degrees of accumulation in the reservoir sediments,and the average content were 2.14,1.73,1.41,7.57,3.56,1.06 and 1.90 times of the background value,respectively,among which the accumulation of Cd was the most serious,mainly from the geochemical properties of Cd and agricultural activities,and Hg,Zn,Cr and Ni were more likely to have the same source,and the sources were both from transportation and industry.From the spatial distribution,the content distribution of Cu,Zn,Cr,Ni,Pb and Hg was the reservoir tail>the reservoir>dam,Cd was the reservoir>lock dam>reservoir tail,and the content of Cd in the reservoir and lock dam was significantly higher than that in the reservoir and lock dam.The ground accumulation index showed that Cd was the most important pollution factor,and Cd was moderate-severely polluted in the sediments,Ni was moderately polluted,and Cu,Hg and Zn were mild-moderate pollution.From the perspective of potential ecological risk index,Cd showed strong ecological risk in reservoir and lock dam,strong ecological risk in reservoir tail,strong ecological risk in reservoir and dam,and moderate ecological risk in reservoir and lock dam,Cd contributed the most to RI,reaching 65.16%,followed by Hg with 22.42%.
Shangyou reservoirsedimentheavy metalthe degree of contaminationecological risk index
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