东平湖表层沉积物重金属富集特征及其污染研究

CHARACTERISTICS OF ENRICHMENT AND ECOLOGICAL RISK ASSESSMENT OF HEAVY METALS IN SURFACE SEDIMENTS OF DONGPING LAKE

对东平湖36个不同位点的表层沉积物中Co、Cr、Cu、Mn、Ni、Pb、Sr、V、Zn等9种重金属元素含量进行分析,结果表明,沉积物中重金属含量分布呈现一定的区域特征,东部湖区明显高于西部湖区。采用富集系数法和地积累指数法对东平湖沉积物重金属污染状况进行了评价,两种方法得出的结果基本一致,东部湖区沉积物中存在Cu、Ni、Pb、Zn污染,其中Cu元素污染风险高于其他元素,污染程度呈自湖东部向湖西部逐渐减少的趋势。主成分分析结果显示,第一主成分贡献率为67.8%,主要载荷因子为Ni、Cr、V、Zn、Co、Pb和Cu,反映了自然和人为两种因素的影响;第二主成分贡献率为14.0%,主要支配Mn和Sr的载荷,反映了地球化学成分的影响。同时也进一步说明工业废水排放、煤和石油的燃烧、废弃物燃烧和农业种植等人为因素是造成东湖区金属元素污染的主要原因。

In this paper,total concentrations of nine heavy metals,including Co,Cr,Cu,Mn,Ni,Pb,Sr,V and Zn were determined in surface sediments from 36 different sites of Dongping Lake. The results showed that the heavy metals had certain regional characteristics in the content distribution,and the content of heavy metals in the eastern lake was higher than that of the western lake. The pollution level of heavy metals in surface sediments of the Dongping Lake was evaluated using the enrichment factors and geo-accumulation index,the results of two methods were basically similar. The pollution of Cu,Ni,Pb,Zn centralized in the eastern part of lake. The ecological risk assessment of Cu was higher than that of other elements,and the contamination degree in the sediments had decreased from eastern to western of the lake. The first principal component（ PC1） in Dongping Lake accounted for 67. 8% of total data variance,which reflected the impact of natural and man-made elements. The second principal（ PC2） accounted for 14. 0%. Ni,Cr,V,Zn,Co,Pb and Cu had greater loadings in the PC1,Mn and Sr had greater loadings in PC2,which reflected the impact of geochemical composition. The results also revealed that industrial discharge,coal and oil combustion,waste combustion and agricultural cultivation were the main source of that contamination.