ABSTRACT

In order to study the characteristics and ecological risks of heavy metal pollution in Dongting Lake, 24 sediment cores were collected in August, 2017. The content characteristics and the pollution status of heavy metals in the study area were analyzed by the method of Igeo, RI and mPEC-Q, and the interrelation and source of heaty metals were evalutated by CA and PCA. The results showed that the concentrations of heavy metals in the surface sediments followed the order of Cr > Pb > Cu > As > Cd > Hg, and the contents of Hg, Cr, Cd, Pb, Cu were 7.0, 2.0, 9.3, 2.2, 2.3 times greater than the background values, respectively. The results using the geo-accumulation index and the potential ecological risk assessment indicated that Cd and Hg were considered as the dominant pollutants. The RI values followed the order of Cd > Hg > Cu > Pb > As > Cr and the mean value of mPEC-Q was 0.43, indicating that the sediments in all of the sampling sites had a 15%-29% probality of toxcity. Source analysis showed that As, Pb, Cd and Cu were homologous and mainly came from the industrial wastewater of the “Four-rivers” basin.

摘要

为研究洞庭湖重金属污染特征及生态风险，于2017年8月采集了24个沉积岩心，采用Igeo, RI方法分析了研究区重金属的含量特征及污染状况。和 mPEC-Q，以及热金属的相互关系和来源由 CA 和 PCA 评估。结果表明，表层沉积物中重金属含量顺序为Cr>Pb>Cu>As>Cd>Hg，Hg、Cr、Cd、Pb、Cu含量依次为7.0、2.0、9.3、2.2 , 分别比背景值大 2.3 倍。使用地累积指数和潜在生态风险评估的结果表明，Cd 和 Hg 被认为是主要污染物。RI 值遵循 Cd > Hg > Cu > Pb > As > Cr 且 mPEC-Q 的平均值为 0.43，表明所有采样点的沉积物具有 15%-29% 的毒性概率。来源分析表明，As、Pb、Cd和Cu是同源的，主要来自“四河”流域的工业废水。