【摘要】 为研究我国南方桉树人工林区水库沉积物中重金属污染程度及垂向分布特征,选取南宁市那降水库和天雹水库为研究对象,采用ICP-AES测定沉积物中Cr、Cu、Zn、As、Cd、Hg和Pb 7种重金属在垂向上的含量分布,并采用地累积指数法对重金属污染进行风险评价。结果表明,天雹水库沉积物中重金属污染较那降水库严重,且7种重金属平均含量远远高于南宁市土壤重金属元素背景值。重金属垂向分布特征显示,重金属Cu和Pb平均含量呈波动增长趋势,Zn和Cd呈持续增长趋势,而Cr、As和Hg呈波动下降趋势。由重金属含量变异系数垂向变化来看,重金属Hg含量变异系数最大,不同深度处均大于0.45,离散程度较高。地累积指数法评价结果表明,重金属污染程度由大到小顺序为:Hg>Cd>Zn>Cu>Pb>Cr>As,重金属Hg累积最严重,属于中度污染程度,且有逐年加重趋势,两个水库的相似点是重金属Hg和Cd也有明显累积,处于中度污染水平。更多还原

【Abstract】 In order to study the heavy metal pollution degree and vertical distribution characteristics in the reservoir sediments of eucalyptus plantation in southern China, Najiang reservoir and Tianbao reservoir Nanning City were selected as research target, Icp-aes was used to determine the vertical distribution of Cr, Cu, Zn, As, Cd, Hg and Pb 7 heavy metals in the sediments. The pollution status was assessed by geo-accumulation index method. Results showed that the heavy metal pollution in the sediment of Tianbao reservoir is more serious than that in Najiang reservoir, and the average concentrations of the above-mentioned seven heavy metals were all higher than the soil background values of Nanning. Vertical distribution characteristics of heavy metals showed that the average concentrations of Cu and Pb presented a fluctuating growth trend, Zn and Cd presented an increasing growth trend, while Cr, As and Hg presented a fluctuating downward trend. The vertical variation of heavy metal content variable coefficient showed that Hg had the greatest coefficient of variation, higher than 0.45 in different depths, with high degree of dispersion. Assessment results based on geo-accumulation index showed that the pollution degree of heavy metals followed the order of Hg, Cd, Zn, Cu, Pb, Cr, As. The accumulation of heavy metal Hg is the most serious, which belongs to moderate pollution, and has an increasing trend year by year. The similarity between the two reservoirs was that Hg and Cd were remarkably accumulated, and were at moderate pollution level.更多还原