阳宗海表层沉积物中的重金属生态风险评估

对从阳宗海湖底表层采集的25组沉积物样品中的10种重金属质量比进行分析,结果表明,Ti、Mn、Zn、V、Cr、Cu、Ni、Co、Pb和As的质量比平均值均超过了当地土壤背景值。而重金属系统聚类分析表明,Zn、Cr、Pb、As高度相关,其污染主要由于人类活动造成;Ti、Mn、V、Cu、Ni、Co的分布特征相似,其污染原因以岩石风化等自然因素为主。单因子富集系数评价表明,阳宗海10种重金属均达到了中度富集程度,其中As、Cu、Cr富集程度较为突出。用Hakanson潜在生态风险指数法评价阳宗海表层沉积物中重金属的生态风险,结果表明,阳宗海表层沉积物中重金属的生态风险总体属轻微程度,阳宗海南岸局部区域达到中等生态风险程度。几种重金属对阳宗海生态风险的贡献由大到小依次为As、Cu、Co、Ni、Pb、Cr、V、Zn、Mn、Ti,其中,As是阳宗海最突出的生态风险因子。

Evaluation of ecological risk of heavy metals in surface sediments from Yangzonghai Lake

The concentrations of ten heavy metals in 25 groups of surface sediment samples from Yangzonghai Lake were analyzed. The results show that the mean concentrations of Ti, Mn, Zn, V, Cr, Cu, Ni, Co, Pb, and As were higher than their natural background values. Cluster analysis indicated that Zn, Cr, Pb, and As were highly correlated whith one another and mainly came from human activities, and Ti, Mn, V, Cu, Ni, and Co were also well correlated and mainly came from the natural lenvironment. The evaluation of the single-factor pollution index indicated that the ten heavy metals were enriched to a certain degree, all reaching the level of medium pollution. The enrichment of As, Cu, and Cr was more prominent than that of the other heavy metals. The Hakanson potential ecological index was used to evaluate the ecological risk of heavy metals in surface sediments of Yangzonghai Lake. The results indicate a slight ecological risk of heavy metals in surface sediments of the lake as a whole, and a medium-level ecological risk of heavy metals in some southern parts of the lake. The heavy metals in surface sediments of Yangzonghai Lake can be grouped in to the descending order according to their contribution to ecological risk： As, Cu, Co, Ni, Pb, Cr, V, Zn, Mn, and Ti. Of them, As was the most prominent factor of ecological risk in surface sediments of Yangzonghai Lake.