华北平原地区交通干线附近土壤重金属有效性研究

选择郑州市郊潮土区域连霍高速公路和京广铁路交叉处附近农田,采集0~20cm土壤样品50个,同时采取远离道路和污染源的农田潮土作对照,研究了土壤DTPA态Ni、Zn、Cu和Pb含量,结果表明,研究区DTPA态Ni、Zn、Cu和Pb的平均含量分别为0.229、1.71、1.02、1.16mg/kg,且Ni和Cu有效性显著高于对照区域(P<0.05),Zn和Pb有效性高于对照区域,,但差异不显著(P>0.05)。小麦地重金属有效性较高,花椰菜地重金属有效性较低。主成分分析结果表明,土壤Ni、Zn、Cu有效性受相同因素影响,Pb有效性受另一因素影响。公路对土壤重金属有效性空间分布有一定影响,铁路对重金属有效性空间分布的影响不明显。以上结果表明,交通干线导致研究区内土壤重金属有效性增加,但程度较小,土地利用方式对土壤重金属有效性有重要影响,土壤重金属有效性空间分布受公路的影响比铁路大。

Availability of Soil Heavy Metals Near the Conjunction of Trunk Railway and Highway in the North China Plain

In this work,50 soil samples of 0-20 cm depth in a field near the conjunction of Lianhuo Expressway and Jingguang Railway in the Chaotu Soil area were collected and control samples were sampled in fields far away from traffic lines and possible pollution source,Soil Ni,Zn,Cu and Pb were extracted with DTPA and analyzed with atomic absorption spectrometry.The average Content of DTPA-extractable Ni,Zn,Cu and Pb were 0.229,1.71,1.02 and 1.16mg/kg,respectively.DTPA-extractable Ni and Cu were significantly higher than the control soil(P<0.05),DTPA-Pb and Zn were also higher than the control soil but the difference was not significant(P>0.05).Higher heavy metal availability was found in soil samples from wheat(Triticum aestivum L.) field than cauliflower(Brassica oleracea var.botrytis)field.Principal component analysis(PCA)indicated that the availability of Ni,Zn,and Cu were affected by the same component,while that of Pb was affected by another component.The Lianhuo Expressway affected the spatial variability of the heavy metals to a certain degree,while the effect of the Jingguang Railway on the spatial variability of the heavy metals was not obvious.The results suggest that soil heavy metal availability in the studied area is enhanced by the road and railway traffic and the effect of railway on the spatial variability is minor.