Integration of magnetism and heavy metal chemistry of soils to quantify the environmental pollution in Kathmandu, Nepal
Integration of magnetism and heavy metal chemistry of soils to quantify the environmental pollution in Kathmandu, Nepal
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DOI：
10.1111/j.1440-1738.2005.00496.x
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发表时间：
2005-12-01
期刊：
影响因子：
1.5
通讯作者：
Appel, E
中科院分区：
文献类型：
--
作者：
Gautam, P;Blaha, U;Appel, E
加德满都城区土壤剖面的磁化率和饱和等温剩磁具有显著的变化特征，可用于区分环境污染。磁化率可用于划分土壤层段，按深度分为正常（< 10（-7）m（3）/kg）、中度增强（10（-7）-< 10（-6）m（3）/kg）和高度增强（>= 10-6 m3/kg）。远离道路和工业场地的土壤通常属于“正常”类别。靠近道路走廊，几厘米深的土壤具有最高的chi，在上面20厘米的间隔内保持较高，并随着深度的增加而降低，从“中等磁性”到大约30-40厘米的“正常”。城市游憩公园土壤剖面上部土壤具有中等的土壤肥力。土壤SIRM有三个不同的中位数采集字段（B-1/2）的组成部分：软（30-50 mT，磁铁矿样相），中间（120-180 mT，可能磁赤铁矿或软磁性赤铁矿）和硬（550-600 mT，赤铁矿）。接近日光表面，SIRM主要由软成分，这意味着城市污染的磁铁矿样阶段的富集结果。原子吸收光谱法的土壤从几个剖面的重金属显示显着的变化（最大值与最小值的比值）的铜（16.3），锌（14.8）和铅（9.3）。在拉尼波哈里，几种金属与chi有很好的相关性，如对数值之间的线性关系所示。而在Ratna公园，chi和SIRM与Zn、Pb、Cu呈显著正相关，与Fe（Mn）、Cr、Ni、Co相关性较差，甚至呈负相关。然而，对于受污染（基本上与交通有关）的土壤剖面，chi表现出显着的线性关系的污染指数的基础上的一些城市元素（铜，铅，锌）的含量，因此，它作为一个有效的参数量化的城市污染。
Soil profiles of the Kathmandu urban area exhibit significant variations in magnetic susceptibility (chi) and saturation isothermal remanence ( SIRM), which can be used to discriminate environmental pollution. Magnetic susceptibility can be used to delineate soil intervals by depth into normal (< 10(-7) m(3)/kg), moderately enhanced (10(-7) -< 10(-6) m(3)/kg) and highly enhanced (>= 10-6 m3/kg). Soils far from roads and industrial sites commonly fall into the 'normal' category. Close to a road corridor, soils at depths of several centimeters have the highest chi, which remains high within the upper 20 cm interval, and decreases with depth through 'moderately magnetic' to 'normal' at approximately 30-40 cm. Soils in the upper parts of profiles in urban recreational parks have moderate chi. Soil SIRM has three components of distinct median acquisition fields (B-1/2): soft (30-50 mT, magnetite-like phase), intermediate (120-180 mT, probably maghemite or soft coercivity hematite) and hard (550-600 mT, hematite). Close to the daylight surface, SIRM is dominated by a soft component, implying that urban pollution results in enrichment by a magnetite-like phase. Atomic absorption spectrometry of soils from several profiles for heavy metals reveals remarkable variability ( ratio of maximum to minimum contents) of Cu (16.3), Zn ( 14.8) and Pb (9.3). At Rani Pokhari, several metals are well correlated with chi, as shown by a linear relationship between the logarithmic values. At Ratna Park, however, both chi and SIRM show significant positive correlation with Zn, Pb and Cu, but poor and even negative correlation with Fe (Mn), Cr, Ni and Co. Such differences result from a variety of geogenic, pedogenic, biogenic and man-made factors, which vary in time and space. Nevertheless, for soil profiles affected by pollution ( basically traffic-related), chi exhibits a significant linear relationship with a pollution index based on the contents of some urban elements ( Cu, Pb, Zn), and therefore it serves as an effective parameter for quantifying the urban pollution.