The Correlational Study Between the Community Characteristics of Benthic Macroinvertebrates and the Potential Ecological Risk of Heavy Metal in Baiyangdian

In the present study,the contents of seven heavy metals were determined using X-ray fluorescence spectrometry in Baiyangdian Lake sediments and their spatial and temporal distribution characters were analyzed in April,August,and November 2011.Hakanson's methodology was applied to determine the degree of contamination and the ecological risk of these heavy metals:Cd,As,Pb,Cu,Hg,Cr and Zn.The results showed that according to the contents,these heavy metals in the surface sediments followed the order as ZnCrCuPbAs CdHg,the potential ecological risk index showed that the heavy metals pollution risk was relatively low in the lake.According to the impact extent of the potential ecological risk,the pollutants could be ranged as HgCdAsCuPbCrZn,the potential ecological risk index is appeared the spatial and temporal differences.The community structure metrics of benthic macroinvertebrate were investigated,and the correlations between the risk index of heavy metals and community structural metrics were analyzed.The distribution of community structural metrics are also appeared the spatial and temporal differences.According to the spatial distribution,the maximum of HBI,PTT,NDT,PC,PDT,and CLI were appeared in Habitat 1,the maximum of PIT,PNI,and CSI were appeared in Habitat 3,the maximum of TR was appeared in Habitata 2;for the temporal distribution,the maximum of HBI,PTT,TR,NDT,PNI,PC,PDT,and CLI were appeared in August,the maximum of PIT and CSI were appeared in April.Through the Pearson correlation analysis between structural metrics and potential risk index,the results showed that the correlation among Eri Cd,Eri Cr,Eri Cu,Eri Pb,RI and NDT is the most significance,between Eri Hg and CSI is the most significance,and between Eri Zn and CLI is the most significance.Thus,we can use the community structural metrics,especially the NDT,CLI,and CSI metrics in the biomonitoring of ecological risk for heavy metal in Baiyangdian Lake.