阳澄湖沉积物重金属空间分布及生物毒害特征

为了解阳澄湖沉积物重金属含量空间分布及污染特征，选取阳澄湖柱状沉积物样为研究对象，采用电感耦合等离子体质谱仪（ICP-MS）、原子荧光光谱仪（AFS）和Hydra-c型全自动测汞仪于2018年2月对阳澄湖15个采样点沉积物柱状样中8种重金属Cr、Ni、Cu、Zn、As、Cd、Pb、Hg进行测定，分析重金属元素含量在水平及垂向的分布特征和污染状况.结果表明，阳澄湖表层沉积物中Cr、Ni、Cu、Zn、As、Cd、Pb、Hg平均含量分别为101.28，68.72，66.54，187.33，15.85，0.45，34.02，0.09mg/kg，是各自背景值的1.34，2.09，2.89，2.88，1.69，4.99，1.54，3.00倍.垂向上重金属的含量随着深度的增加呈现出下降的趋势.对8种重金属进行相关分析和聚类分析，除As、Ni和Hg外，不同重金属之间存在着显著相关关系（P<0.05），这说明阳澄湖沉积物重金属之间存在着一定的同源性.采用沉积物质量基准（SQG）对阳澄湖沉积物中重金属生物毒性效应进行了评价，结果表明，阳澄湖沉积物中Ni有75%以上的可能性出现生物毒害效应，Cr、Cu、Zn、As则有10%~75%的可能性产生生物毒害效应，而Cd、Pb和Hg造成的生物毒害效应的可能性较小.ERMQ评价结果表明，阳澄西湖沉积物中重金属造成生物毒害的风险较大，其余湖区发生重金属生物毒害的风险较小.

Characteristics of spatial distribution andbiological toxicity for heavy metals in sediments of the Yangcheng Lake

To explore thespatial distribution and pollution characteristics of heavy metals in theYangcheng Lake, core sediment samples were analyzed. ICP-MS, ASFand Hydra-c automatic mercury measuring instrument were applied to quantify eight heavy metals (Cr, Ni, Cu, Zn, As, Cd, Pband Hg) in sediments samples from 15sampling sites of the Yangcheng lake in February 2018, analyzing the spatial distribution and pollution condition of heavy metals. The results indicated that the average contents of Cr, Ni, Cu, Zn, As, Cd,Pband Hg in the surface sediments were 101.28mg/kg, 68.72mg/kg, 6.54mg/kg, 87.33mg/kg, 5.85mg/kg, 0.45mg/kg, 34.02mg/kg and 0.09mg/kg, respectively, which were 1.34, 2.09, 2.89, 2.88, 1.69, 4.99, 1.54, 3.00times of the soil background values in Jiangsu Province.Contents of heavy metals showed a downward trend with increasing depth vertically. Cluster analysis and correlation analysis of eight metals manifested that except for As, Ni and Hg, there was a significant correlation between other heavy metals (P<0.05), which indicated certain homology among the heavy metals in sediments. The bio-toxicity effects of heavy metals in Yangcheng Lake sediments were evaluated by sediment quality guideline (SQG). The results suggested that Ni was more likely to have adverse effect on origanisms, with a probability of 75% and heavy metals like Cr, Cu, Zn, andAs were 10% to 75% likely to have biological toxic effects. Further analysis based on ERMQ evaluation showed the risk of adverse effects was higher in the west Yangcheng Lake compared to the other parts of the lake.