Key Laboratory of West China's Environmental System, Ministry of Education, Lanzhou University of China, Lanzhou 730000, China.
Environ Pollut. 2014 Jan;184:335-46. doi: 10.1016/j.envpol.2013.08.024. Epub 2013 Oct 2.
Increasing urbanization and industrialization over the world has caused many social and environmental problems, one of which drawing particular concern is the soil pollution and its ecological degradation. In this study, the efficiency of magnetic methods for detecting and discriminating contaminates in the arid and semi-arid regions of northwestern China was investigated. Topsoil samples from six typical cities (i.e. Karamay, Urumqi, Lanzhou, Yinchuan, Shizuishan and Wuhai) were collected and a systematic analysis of their magnetic properties was conducted. Results indicate that the topsoil samples from the six cities were all dominated by coarse low-coercivity magnetite. In addition, the average magnetite contents in the soils from Urumqi and Lanzhou were shown to be much higher than those from Karamay, Yinchuan, Shizuishan and Wuhai, and they also have relatively higher χlf and χfd% when compared with cities in eastern China. Moreover, specific and distinctive soil pollution signals were identified at each sampling site using the combined various magnetic data, reflecting distinct sources. Industrial and traffic-derived pollution was dominant in Urumqi and Lanzhou, in Yinchuan industrial progress was observed to be important with some places affected by vehicle emission, while Karamay, Shizuishan and Wuhai were relatively clean. The magnetic properties of these latter three cities are significantly affected by both anthropogenic pollution and local parent materials from the nearby Gobi desert. The differences in magnetic properties of topsoil samples affected by mixed industrial and simplex traffic emissions are not obvious, but significant differences exist in samples affected by simplex industrial/vehicle emissions and domestic pollution. The combined magnetic analyses thus provide a sensitive and powerful tool for classifying samples according to likely sources, and may even provide a valuable diagnostic tool for discriminating among different cities.
随着世界范围内城市化和工业化的不断推进，带来了诸多社会和环境问题，其中土壤污染及其生态退化问题尤为引人关注。本研究旨在探讨磁学方法在探测和识别中国西北地区干旱半干旱地区污染物方面的有效性。采集了来自六个典型城市（克拉玛依、乌鲁木齐、兰州、银川、石嘴山和乌海）的表层土壤样本，并对其磁性特征进行了系统分析。结果表明，六个城市的表层土壤样本均以粗粒低矫顽力磁铁矿为主。此外，乌鲁木齐和兰州土壤中的磁铁矿含量明显高于克拉玛依、银川、石嘴山和乌海，其χlf 和 χfd%值也相对较高，表明它们受到了来自东部地区城市所没有的工业和交通污染源的影响。此外，通过综合分析各种磁性数据，在每个采样点都识别出了独特的土壤污染信号，反映了不同的污染源。乌鲁木齐和兰州的污染主要来自工业和交通，银川则以工业发展为主，部分地区受到车辆排放的影响，而克拉玛依、石嘴山和乌海相对较为清洁。这些城市的磁性特征既受到人为污染的影响，也受到附近戈壁沙漠基岩的影响。受混合工业和单一交通排放影响的表层土壤样品的磁性特征差异不明显，但受单一工业/车辆排放和家庭污染影响的样品之间存在显著差异。因此，综合磁性分析为根据可能的污染源对样品进行分类提供了一种敏感而强大的工具，甚至可能为不同城市之间的区分提供有价值的诊断工具。
