白洋淀底栖动物群落特征与重金属潜在生态风险的相关性研究

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

在2011年4—11月,对白洋淀表层沉积物重金属含量和底栖动物群落的时空分布特征进行了分析,探讨了重金属分布对底栖动物群落结构特征的影响,采用Hakanson潜在生态风险指数法综合评价了白洋淀沉积物中重金属污染状况和潜在风险程度。结果表明,沉积物中重金属含量大小顺序为Zn>Cr>Cu>Pb>As>Cd>Hg,表层沉积物中重金属的潜在生态风险处于低风险水平,综合潜在生态风险指数为17.55～62.89;各种重金属元素的单项潜在生态风险大小顺序为Hg>Cd>As>Cu>Pb>Cr>Zn;潜在生态风险分布也存在时空差异,就空间分布而言,生境1中最高,依次为生境2和生境3;就时间分布而言,8月最高,依次为4月和11月。同时,对白洋淀的底栖动物的群落结构也进行了调查分析,结构指标分布也存在时空差异。就空间分布而言,HBI、PTT、NDT、PC、PDT、CLI的最大值均出现在生境1,PIT、PNI、CSI的最大值出现在生境3,TR的最大值出现在生境2;就时间分布而言,HBI、PTT、TR、NDT、PNI、PC、PDT、CLI的最大值出现在8月,PIT、CSI的最大值出现在4月。并对重金属潜在生态风险及其与底栖动物生物指标的相关性进行了探讨,结果表明EriCd、EriCr、EriCu、EriPb,以及RI与NDT的相关性最显著,EriHg与CSI的相关性最显著,EriZn与CLI的相关性最显著。因此,在白洋淀重金属生态风险的生物监测中,可以考虑运用底栖动物的NDT、CLI、CSI指标。

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.