成都盆地平原区浅层土壤Cd、Pb、Zn分布特征及其成因初探

通过多目标地球化学调查在成都盆地平原区浅层土壤内发现呈面状分布的Cd、pb、Zn等元素高值区.为了研究它们的成因,应用多元统计方法分析了这些元素在不同景观区及不同环境介质中的分布特征及相关关系,利用参考元素对Cd、Pb、Zn的富集含量进行了定量估算.结果表明,平原区浅层土壤内Cd、Pb、Zn元素的分布明显不同于物源区及平原区深层土壤,在元素之间的典型相关关系及元素富集的分布特征上,均表现出明显的人为源特征.Cd、Pb、Zn元素的富集主要出现在平原区中部的城镇及农田区,与成都盆地浅层样地球化学图上的高值区一致.Cd、Pb、Zn元素的富集,是在自然背景的基础叠加了人为源含量,但尚未达到危害程度.

Distribution and origin of Cd, Pb and Zn in topsoils of plain region of Chengdu Basin

Flat-shaped areas of high concentrations of Cd, Pb and Zn in topsoils of plain region are detected by the multi-purpose geochemistry survey in Chengdu Basin. The distribution and correlations of Cd, Pb and Zn in the different landscapes and environmental samples are discussed using statistical analysis with the aim of discussing their origins, the enrichment value are estimated by a reference element. The results indicate that the distribution of Cd, Pb and Zn in topsoils of the plain region is different obviously from that in deep soils of the plain region and the genetic area, which is apparently anthropogenic input according to canonical correlations and the distribution characteristics of enrichment value. The enrichments of Cd, Pb and Zn occur mainly in the urban area and agricultural topsoils in the plain region, which agrees with the high value area in the geochemistry maps in topsoils of Chengdu Basin. The enrichments of Cd, Pb and Zn are the superposition of anthropogenic source upon the natural background, but the pollution is serious yet.