东北农田黑土中Cd、Pb、As含量空间分异特征分析

采用点面结合方法,研究了东北区农田黑土中Cd、Pb、As含量的空间分异特征。结果表明,三种元素含量的变异系数为Cd>Pb>As。Cd、Pb的平均含量高于其背景值;其中Cd有45个样品超过了国家二级标准限值。Cd、Pb、As含量由南至北未表现出明显的分布规律。对煤矿区周围农田土壤的调查发现,煤矿是其周围农田土壤的主要污染源。采用最优内插法得到了长春市市郊农田黑土中Cd、Pb、As含量的空间分布图,结果表明人为活动显著改变了局部地区Cd、Pb、As的含量,污染源主要为汽车尾气和固体废弃物的堆积。对三种元素垂直分布进行了分析,剖面土层Cd、Pb、As主要来自于表面污染源,向下迁移作用还不很强烈。

Spatial Distribution Characteristics of Cd, Pb and As Contents in the Farmland Black Soil in the Northeast of China

Analyses of the spatial distribution of Cadmium(Cd),Lead(Pb) and Arsenic(As) contents in farmland black soil in the Northeast of China indicated that the variance coefficient of Cd content was the highest,As the lowest,and Pb medium.Average contents of Pb and As were higher than the background values for black soil,and there were 45 samples,of which the content of Cd was higher than the soil environment quality standard.There were no distinct patterns in the distribution of Cd,Pb and As in the direction of latitude.According to the results of investigation,pollution of the farmland near coal mines was relatively heavy.Kriging interpolation method was used to create the distribution maps of the three elements in the farmland of the suburb of Changchun city,and it was found that the accumulation of Cd,Pb and As in the black soil was obvious.Analyses of vertical distribution showed that Cd,Pb and As were mainly accumulated within the depth of 0-20cm,and the contents in the subsurface layer were relatively lower.