鄱阳湖沉积物重金属空间分布及潜在生态风险评价

Spatial Distribution and Potential Ecological Risk Assessment of Heavy Metals in Sediments of Poyang Lake

通过分析鄱阳湖沉积物重金属空间分布特征,评价其潜在生态风险,并探讨了主要重金属污染来源。结果表明：鄱阳湖沉积物7种重金属元素Cd、Hg、As、Cu、Pb、Cr、Zn含量平均值分别为0.67、0.078、17、51、72、42.9、117 mg/kg,除Cd外,其余6种元素均明显高于相应的背景值。从空间分布来看,Cd、Cr含量总体呈现东南、西北部偏高的现象,而Hg、Cu、Pb含量总体呈现东南部偏高的现象,As、Zn的含量分布相对平均。Hg、Cu、Pb、Zn 4种金属元素之间存在极显著相关性,表明这些元素污染具有同源性。潜在生态风险评价结果显示,单个重金属潜在生态风险顺序为Cu〉Hg〉Pb〉Cd〉As〉Cr〉Zn;从综合潜在生态风险分析来看,整个湖区的RI值为46.4～476.3,平均值为165.4,属于中等潜在生态危害,其中湖区东南部综合潜在生态风险最高。Cu、Hg、Pb等重金属主要来自乐安河流域工业排放。

The objection of this paper is to investigate the spatial distribution of heavy metal and their potential ecological risk in sediments of Poyang Lake, and explore the pollution sources. The results can be summarized as the following：The concentration of Cd, Hg, As, Cu, Pb, Cr and Zn were 0. 67, 0. 094, 17, 51, 72,42.0, 117 mg/kg, respectively, which were all above the soil background values of Poyang Lake beside Cd. The concentrations of Cd, and Cr in the southeast and northwest of Poyang Lake and were relatively high, the concentrations of Hg, Cu and Pb in the southeast of Lake were relatively high, while the concentrations of As and Zn were relatively average in the entire Poyang Lake. The concentration of Hg, Cu, Pb and Zn were significantly correlated to each other, which indicating those heavy metal had the same source. The sequence of potential ecological risk of heavy metal was Cu 〉 Hg 〉 Pb 〉 Cd 〉 As 〉 Cr 〉 Zn; The average potential ecological risk indexes was 165.4 （ ranged from 46.4-476.3） , suggesting a moderate ecological risk. In addition, the ecological risk indexes in the southeast of Poyang Lake were highest. The main metal heavy in the sediment of Poyang Lake is most from the industrial discharge at Le-an river valley.