研究报告
王博,夏敦胜,余晔,贾佳,田世丽,刘现彬.环境磁学在监测城市河流沉积物污染中的应用[J].环境科学学报,2011,31(9):1979-1991
环境磁学在监测城市河流沉积物污染中的应用
- Use of environmental magnetism to monitor pollution in the river sediment of an urban area
- 基金项目：中国科学院"百人计划"项目(No.0827631002);国家自然科学基金项目(No.41071125)
- 作者
- 单位
- 王博
- 兰州大学西部环境教育部重点实验室,兰州 730000
- 夏敦胜
- 1. 兰州大学西部环境教育部重点实验室,兰州 730000;
2. 中国科学院寒区旱区环境科学与工程研究所,兰州 730000
- 余晔
- 中国科学院寒区旱区环境科学与工程研究所,兰州 730000
- 贾佳
- 兰州大学西部环境教育部重点实验室,兰州 730000
- 田世丽
- 中国科学院寒区旱区环境科学与工程研究所,兰州 730000
- 刘现彬
- 兰州大学西部环境教育部重点实验室,兰州 730000
- 摘要：环境磁学因简便、快速、经济等特征而逐渐广泛应用于城市环境污染研究,并得到了大量学者的认可.与此同时,对环境磁学污染响应机理的研究也成为当前环境磁学发展突破点.本文选取流经兰州市不同功能区(绿地区、生活区、商业区、工业区)的典型河流——寺儿沟为研究对象,通过环境磁学、元素、粒度等指标对其4个功能区河段沉积物的磁性特征进行研究,探讨环境磁学对不同功能区的污染响应特征,研究结果表明:绿地区和居民区磁性特征以磁铁矿为主导,同时存在磁赤铁矿的贡献,磁性矿物浓度较低;商业区和工业区磁性特征以磁铁矿为主导,磁性矿物浓度较高.绿地区河流沉积物中原生磁赤铁矿的含量与黄土沉积物接近,生活区较低,商业区和工业区已几乎不含原生磁赤铁矿,原生磁赤铁矿可以作为兰州地区污染的指示性矿物.对兰州地区而言,磁晶粒度并非区分污染的有效指标.对比沉积物的磁学性质和污染程度发现:商业区河段沉积物的污染程度虽然最高,但仅表现出较高的磁化率;工业区河段沉积物的污染程度较高,但仅表现出最高的磁化率,暗示当元素富集程度很高时,沉积物的磁化率出现明显升高;然而这种升高在不同类型的沉积物中表现出非线性规律.此研究结果指示在通过磁学手段测量沉积物污染程度的过程中,必须通过各种磁学手段甚至其它参数进行对比判断来源的差异,将物源影响去除后,磁学参数才能更为准确的指示沉积物的污染程度.
- Abstract：With the advantages of fast, sensitive, inexpensive and nondestructive measurement, environmental magnetism analysis has been used as a preliminary method to study pollution effects before starting time- consuming and expensive chemical methods. In this study, sediments from a representative river, the Sier River, were selected for measurement of particle size, elemental composition and magnetic properties with the purpose of exploring the sediment magnetism response to different nearby landuses. The results indicate that river sediments collected in the Green district and residential areas are characterised by low concentrations of magnetic minerals and a small amount of maghaemite, while those collected in the commercial district and industrial areas are characterised by high magnetic mineral content and low maghaemite. The origin of maghaemite can be used to indicate the river pollution level, but mineral grain sizes are not an effective indicator of pollution intensity in an urban area. Comparison of the sediment magnetic properties with the degree of pollution reveals that, although the degree of pollution is the highest in the commercial district, the highest magnetic susceptibility was measured in sediments from the industrial area, which implies that although the magnetic susceptibility increased significantly when the degree of element enrichment was high, the increase is nonlinear in different types of sediments. The study indicates that various magnetic parameters should be used and the influence of source should be minimized when monitoring the pollution using environmental magnetism analysis.
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