海南岛表层及深层土壤重金属分布特征及源解析

Distribution Characteristics and Source Identification of Heavy Metals in Topsoils and Subsoils of Hainan Island

地学统计及多元分析是判断土壤中重金属元素来源和影响因素的有效方法。区域尺度上不同岩性地区表层及深层土壤中重金属元素含量和空间分布的对比分析,也可以为区分重金属元素来源提供有价值的信息。本研究在海南岛共采集了8713件表层土壤样品和2197件深层土壤样品,分别测定了其中8种重金属元素和Sc等元素含量。结果表明,表层和深层土壤中As、Co、Cr、Cu、Pb、Zn、Cd、Hg的平均含量分别为5.29 mg/kg、11.95 mg/kg、60.79 mg/kg、17.24 mg/kg、26.18 mg/kg、51.22 mg/kg、0.081 mg/kg、0.043 mg/kg和5.53 mg/kg、12.89 mg/kg、65.24 mg/kg、19.97 mg/kg、29.15 mg/kg、58.87 mg/kg、0.065 mg/kg、0.029 mg/kg。通过Pearson相关性分析和多元成分数据分析,发现影响海南岛表层和深层土壤中重金属元素分布的主要因素为成土母岩的岩性、成土过程以及人类活动。分析结果表明,As、Co、Cr、Cu、Pb、Zn元素主要继承于土壤母质并受成土过程影响,而Cd和Hg元素受到人为活动输入影响较大。

Geo-statistical and multivariate analyses are effective methods to determine the source and impact factors on heavy metals in the soil.The comparative analysis of contents and spatial distribution of heavy metals in topsoils and subsoils of different lithologic regions on a regional scale can also provide valuable information for distinguishing the sources of heavy metals.In our study,concentrations of 8 heavy metals were respectively measured in 8,713 topsoil samples and 2,197 subsoil samples collected from Hainan Island.The mean concentrations of As,Co,Cr,Cu,Pb,Zn,Cd,Hg in topsoils and subsoils were 5.29 mg/kg,11.95 mg/kg,60.79 mg/kg,17.24 mg/kg,26.18 mg/kg,5122 mg/kg,0.081 mg/kg,0.043 mg/kg and 5.53 mg/kg,12.89 mg/kg,65.24 mg/kg,19.97 mg/kg,29.15 mg/kg,58.87 mg/kg,0.065 mg/kg,0.029 mg/kg,respectively.The dominant impact factors including lithology of soil parent material,pedogenesis and human activities were figured out for heavy metals both in topsoils and subsoils by using Pearson correlation analysis and multivariate compositional analysis.The result shows that As,Co,Cr,Cu,Pb and Zn mainly come from the inheritance of soil parent material and influence of the pedogenesis,while Cd and Hg are greatly affected by the input of human activities.