仙鹤湖重金属污染及其潜在生态风险分析

水体是重金属元素的重要载体，其含量高低能反映水环境质量现状。采集仙鹤湖水样品，分析仙鹤湖湖水中Fe、Mn、Pb、Cd、V、Zn、Ni、As、Se、Mo、Ba、Sb 12种重金属元素含量特征，并用Hakanson潜在生态危害指数法评价其生态危害，旨在为合理预防和治理仙鹤湖的重金属污染以及仙鹤湖生态系统的修复提供基础资料。结果表明，与“全国土壤环境质量标准”对比，湖水中主要是Pb、Cd、As、Fe、Mn、Mo、V、Ba超标，重金属污染强度总体上是湖外围＞内湖。不同重金属间的相关性分析结果表明，Ni-As、As-Mo之间呈极显著相关，说明这3种元素污染源可能相同，V-Ba呈显著不相关，说明这2种元素的污染源可能不同，几种污染重金属与胶体矿物元素Fe、Mn间的相关性不大，说明在所调查沉积物中，Fe/Mn氧化物或氢氧化物共沉淀或吸附Pb、Cd、V、Zn、Ni、As、Se、Mo、Ba、Sb元素量较少。由潜在生态风险评价结果可知，仙鹤湖水已具极强生态危害，各重金属对仙鹤湖生态风险影响程度由高到低依次为：Cd>As>Pb>V>Mn>Ni>Zn。

Heavy Metals Pollution and Its Potential Ecological Risk Assessment of Xianhe Lake

Heavy metals are mainly carried in sediment of water body, their contents play important role on the environmental quality of the water body. The aim of this study is to control heavy metal pollution in Xianhe Lake and provide the basic information of ecosystem recovery of the water. The contents and characteristics of 12 heavy metals （Fe, Mn, Pb, Cd, V, Zn, Ni, As, Se, Mo, Ba, Sb） of surface sediments from the water of Xianhe Lake were analyzed. Ecological risk index presented by Hakanson to assess the potential ecological risk of Xianhe Lake was utilized. The results showed that＇ the water of Xianhe Lake was polluted mainly by Pb, Cd, As, Fe, Mn, Mo, V and Ba compared with the ＇environmental quality standard for soils＇, and the lake perimeter of heavy metal pollution of Xianhe Lake was stronger than that of neihu. According to the correlation analysis of various heavy metals, there was a remarkable correlation between Ni-As, As-Mo, which suggested their origins were the same. There was unremarkable correlation between V-Ba, which suggested their origins were different. While the correlation between Fe, Mn and other heavy metals was weak, which indicated that Pb, Cd, V, Zn, Ni, As, Se, Mo, Ba and Sb deposited or adsorbed by Fe/Mn oxides or hydroxides was less in the investigated water body. Based on the potential ecological risk assessment results, the water of Xianhe Lake had reached a high ecological risk level, and the order of ecological risk of heavy metals in water of Xianhe Lake in the decline order was Cd 〉 As 〉 Pb 〉 V 〉 Mn 〉 Ni 〉 Zn.