城市表层土壤重金属与磁化率的多尺度空间变异分析

采集徐州市城区167个表层土壤的样品,并分别测定了磁化率χ的数值及其5种重金属(Cu、Zn、Mo、Cd和Pb)的含量.利用多元因子克里金分析上述研究变量在局部尺度(1 km变程)和区域尺度(5.5 km变程)的空间变异特征.研究表明,徐州城市表土中的磁化率与重金属在局部尺度上主要受到交通、工业和农业等人为因素的影响,在区域尺度上,则以土壤母岩等自然因素为主导.磁化率#与Cu、Zn、Mo、Cd、Pb在局部尺度上的结构相关性较高,在此尺度内选择适当的采样间隔,有助于提高磁化率作为上述重金属污染替代指标进行空间制图的精度.

Multi-scale spatial variability analysis of heavy metals and magnetic susceptibility in urban topsoil

Soil samples (n=167) were collected from Xuzhou city, China. The value of magnetic susceptibility and the content of heavy metals (Cu, Zn, Mo, Cd and Pb) were determined. Factorial kriging analysis was applied to investigate spatial variability of magnetic susceptibility and heavy metals at the local (1 km range) and the regional (5.5 km range) scales. Our results indicate that all the variables were influenced by anthropogenic activities (mainly transportation, industry and agriculture) at the local scale. However, their spatial variability at the regional scale is related to soil parent rock. The structural correlations between magnetic susceptibility and the five heavy metals were more significant at the local scale. We therefore conclude that selecting an appropriate sampling interval in this scale is an effective way in improving accuracy of spatial mapping when magnetic susceptibility is used as a proxy for studying heavy metals.