丹江口水库沉积物重金属形态分布特征及其迁移能力

以丹江口库区及其支流为研究对象,采用连续分级提取法研究了表层沉积物中Cr、Ni、Cu、Zn、As、Cd、Hg和Pb各形态的空间赋存特征和相对比例,探讨了各形态金属的稳定度并对其进行污染评价.结果表明,表层沉积物各形态金属分布都具有明显的空间差异性,高值集中于库区中部、西部入库支流和丹江库区西北部.沉积物中Pb的可还原态、Cd的弱酸提取态占总量的质量分数较高,分别达到54.91%和42.19%,其余重金属则以残渣态为主.重金属稳定度分析表明,8种金属稳定性顺序为Cr >Pb >As >Ni >Cu >Hg >Zn >Cd,Cd在大部分点位处于不稳定状态,快速解吸释放的风险较大.

Heavy metal in sediment of Danjiangkou Reservoir chemical speciation and mobility.

BCR three stage sequential extraction procedure was applied to examine the spatial occurrence characteristics and relative ratio of the speciation of Cr, Ni, Cu, Zn, As, Cd, Hg and Pb in the sediments from Danjiangkou reservoir, and meanwhile their stability and pollution assessment were discussed. All types of metals had obvious spatial heterogeneity; their high value was grouped in the middle of the reservoir, the west of tributaries and the northwest of Danjiang reservoir. Most metals mainly existed in residue state except for Pb and Cd, the reducible Pb and acid soluble Cd respectively accounted for 54.91% and 42.19% of the total content. The stability of eight studied metals was in the order of Cr >Pb >As >Ni >Cu >Hg >Zn >Cd. Cd was unstable in most studied sites, and there was higher risk of quick desorption and release.