Magnetic properties of different pollution receptors around steel plants and their environmental significance
Magnetic properties of different pollution receptors around steel plants and their environmental significance
复制标题
钢铁厂周围不同污染受体的磁特性及其环境意义
DOI：
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发表时间：
2009
影响因子：
1.4
通讯作者：
Liu Qing-Song
中科院分区：
文献类型：
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作者：
Zhang Chun-Xia;Huang Bao-Chun;Liu Qing-Song
我们的目标是利用不同材料的磁性来有效地监测钢铁厂周围的环境污染：树皮、草地和花园表面的飞灰、土壤以及四种不同树木的年轮芯。样品分别采自河北省兴隆县和湖南省娄底县两个钢铁厂附近。以草为短期受体，树皮和土壤为中短期受体，年轮芯为中长期受体，可以对不同时间尺度的环境污染进行评价。磁性测量包括磁化率和剩磁的温度依赖性、磁滞回线、一阶反转曲线（FORC）和低温实验，以及微观SEM、EDX和XRD分析。结果表明，粉煤灰和土壤样品中主要以磁铁矿、赤铁矿和纯铁为主。磁铁矿颗粒呈球形，不同受体中的颗粒尺寸在8 - 50 μm之间，而纯铁颗粒通常具有不规则形状。低温测量结果表明，杨柳的年轮核中存在磁铁矿颗粒，而极地、枫树和樟脑的年轮核中很可能主要是顺磁性或超磁性矿物，而铁磁性矿物很少或不存在。这表明，只有杨柳年轮核心可以作为重工业活动引起的长期污染的磁性指标。我们的结论是，岩石磁性和显微镜调查可能是一种有效的方法，用于确定磁性矿物和重工业活动引起的铁磁体的粒度，它们提供了一个快速和有用的技术监测环境污染。
Our aim is to effectively monitor environmental pollution around steel plants using magnetic properties of different material: fly ashes on the surfaces of tree bark, grass and garden, soil, and tree ring cores from four different trees. Samples were collected from the vicinity of two steel plants, located at Xinglong County ( Hebei Province) and Loudi County (Hunan Province), respectively. Environmental pollution on different time-scales could be assessed by using grass as short-term receptor tree bark and soil as short-to medium-term receptors and tree ring cores as medium- to long-term receptor. Magnetic measurements included temperature-dependence of magnetic susceptibility and remanence, hystersis loops, First-Order Reversal Curves (FORCs) and low-temperature experiments, and microscopic SEM, EDX and XRD analyses. The results indicate that the fly ashes and soil samples are predominated by magnetite, hematite and pure iron. Magnetite grains are spherical and grain size in different receptors ranges from 8 to 50 μm whilst the pure iron grains generally have an irregular shape. Low-temperature measurements show that magnetite grains exist in the tree ring cores of willow, whereas the tree rings cores of polar, maple and camphor are most likely dominated by para-or supermagnetic minerals whereas ferromagnetic minerals are scarce or absent. This suggests that only the willow tree ring core could serve as a magnetic indicator for long-term pollution induced by the heavy industry activity. We conclude that rock magnetic and microscopic investigations could be an effective method for determining magnetic minerals and grain sizes of ferromagnets induced by heavy industry activity; they provide a rapid and useful technique for monitoring environmental pollution.