黄河甘宁蒙段表层沉积物中重金属元素含量及其形态分析

到目前为止，关于水环境中重金属浓度和形态分布的研究有许多报道。但是关于黄河上游，特别是对黄河甘宁蒙段区域重金属的研究报道仍需进一步深入。在相关研究工作的基础上，使用HR-ICP-MS和BCR连续提取法主要对2011年丰水期黄河甘宁蒙段12个采样点表层沉积物Cd，Pb，Cr，V，Co，Ni，Cu和Zn重金属元素的含量，形态和潜在风险进行测定与分析。结果表明：所有采样点各重金属元素含量顺序相同：Cr>V>Zn>Cu>Ni>Pb>Co>Cd，与各采样点所在区域土壤中背景值相比，S5采样点Cd元素的含量水平最高(1.30 μg·g-1) 约为背景值(0.103 μg·g-1)的13倍。通过I_geo对重金属进行污染评价，结果显示S5采样点Cd元素为强污染水平(I_geo=3.08)，内蒙古段四个采样点(S1—S4)Cd表现为中强度污染水平，I_geo位于2.02~2.90之间;此外，富集因子(EF)评价结果发现，研究区域表层沉积物中八种重金属均受到人为活动的污染。根据潜在生态风险指数(RI)结果，S5和S3采样点为高生态风险，其他采样点为中等生态风险。BCR连续提取法结果显示Cd的有效性最高，其次为Co和Ni，V和Cr有效性最低。根据形态分析风险评估准则 (RAC)，Cd在S1—S4采样点有高风险，在S5采样点有很高风险;而对于Ni和Co来说，12个采样点中均表现为中等风险。研究结果和结论可为相关政府部门提供重要的研究信息。

Heavy Metals Contents and Speciation in Surface Sediments from Gansu,Ningxia and Inner Mongolia Sections of the Yellow River of China

So far, many investigations had been made on the concentration and species distribution of heavy metals in aquatic environments. However, there are only a few studies on heavy metals in upper reaches of the Yellow River, especially in Gansu, Ningxia and Inner Mongolia sections. We have literatures related to the Yellow River, in this work, we remarkably discussed about the contents, speciation and potential risks of Cd, Pb, Cr, V, Co, Ni, Cu, and Zn in surface sediments from 12 sampling sites in Gansu, Ningxia, and Inner Mongolia sections of the Yellow River of China in 2011 year wet season by high resolution inductively coupled plasma mass spectrometer (HR-ICP-MS) and sequential extraction procedure of BCR method. The results indicated that the metals contents were arranged as Cr>V>Zn>Cu>Ni>Pb>Co>Cd in all sites. Comparing with the background value of soil in local section, Cd showed the highest level at S5 (1.30 μg·g-1), which was almost 13 times higher than the background value (0.103 μg·g-1). Pollution assessment indicated that Cd presented a strong polluted status with the geo-accumulation index (I_geo) value of 3.08 at S5, moderately to strong polluted status with the I_geo ranged from 2.02 to 2.90 in Inner Mongolia section (S1—S4). Moreover, enrichment factor (EF) showed that all heavy metals in these sediments have been influenced by anthropogenic activities. According to potential ecological risk index (RI), S5 and S3 demonstrated high ecologic risk of heavy metals, while other sampling sites showed moderately ecological risk. The results of BCR exhibited that Cd was the most available metal, followed by Co and Ni, while V and Cr were unavailable in the sediments. Risk assessment code (RAC) exhibited high risk for Cd at S1—S4 and very high risk at S5, while medium risk for Ni and Co at all sites. The results and conclusions may be important information and therefore of interest to the relevant departments of the governments.