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| 宁夏贺兰县土壤重金属分布特征及其生态风险评价 |
| Distribution characteristics and ecological risk assessment of soil heavy metal in Helan County of Ningxia, China |
| 投稿时间：2018-07-23 |
| DOI：10.13254/j.jare.2018.0191 |
| 中文关键词: 宁夏，土壤，重金属，分布特征，潜在生态风险 |
| 英文关键词: Ningxia, soil, heavy metal, distribution characteristics, potential ecological risk |
| 基金项目:环保部公益性项目（201509044） |
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| 中文摘要: |
| 为研究西北地区农田土壤重金属分布特征及其生态风险，以宁夏贺兰县为研究区，采集农田表层土壤样品140个，分析测试了Cr、Ni、Cu、Zn、As、Cd和Pb含量，并采用内梅罗综合污染指数和Håkanson潜在生态风险指数法进行了重金属生态风险评价。结果表明：宁夏贺兰县农田表层土壤Cr、Ni、Cu、Zn、As和Pb元素均低于国家土壤环境二级标准，仅有1.42%样点的Cd元素出现超标；与宁夏土壤背景值相比，各元素都有不同程度的累积，其中Cd和Ni元素超出背景值的点位率分别达到100%和85%；土壤各重金属元素的分布特征较为一致，各元素含量分布比较均匀，高值区集中在中部和东部地区，主要受人类活动的影响。单因子污染指数分析结果表明，Cd元素有0.71%的点位为中度污染水平，Ni和As分别有7.14%和5%的点位处于尚清洁水平，Cr、Cu、Zn、Pb全部清洁，尚未造成污染。重金属的单项生态风险指数（Eri）表明，Cd元素的平均潜在生态风险指数为97.68，达强烈风险水平，是最主要的生态风险元素。宁夏贺兰县农田土壤环境质量整体良好，Cd和Ni累积严重，值得关注。 |
| 英文摘要: |
| Ningxia Helan County was taken as the research area in this paper to study the distribution characteristics and ecological risk of heavy metals in farmland soil in northwest China. 140 topsoil samples were collected aiming to analyze and measure the concentration of Cr, Ni, Cu, Zn, As, Cd and Pb belonging to heavy metal elements. The distributions, soil environment status and ecological risk of the seven heavy metals were studied by Nemerow pollution index and Håkanson potential ecological risk index methods. The results showed that concentrations of Cr, Ni, Cu, Zn, As and Pb were all lower than the second-level of Environmental Quality Standard for Soils of China except that concentrations of Cd of 1.42% samples were appeared to exceed the standard. Compared with the background values, seven heavy metals of all samples showed different degree accumulation, in which Cd, Ni elements beyond the background value ratio reached 100% and 85%. Spatial distribution of the concentrations of the seven heavy metals had obvious accordance. The content of each element was evenly distributed. The high content of each element was concentrated in the central and eastern part of Helan County, which was related to human activities. The calculation results of single-factor pollution index showed that among the 140 soil samples, 0.71% of Cd were moderate contamination, 7.14% of Ni and 5% of As were slight clean, Cr, Cu, Zn, Pb of all samples were all clean. According to the individual potential ecological risk index (Eri) of heavy metals, the average potential ecological risk index of Cd element was 97.68, which indicated that Cd had reached the serious risk level, becoming the main element of potential ecological risk. All in all, the quality of farmland soil in Helan County of Ningxia is good, but it is noteworthy that the concentration of Cd, Ni has a serious accumulation. |
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