基于多元统计和傅立叶和谱分析的土壤重金属的来源解析及其风险评价

Soil heavy metal sources identification and associated risk assessment using multivariate statistical and Fourier spectral analysis

分析珠江三角洲腹地佛山顺德区208个蔬菜地表层土样Cu、Ni、Cr、As、Pb、Zn、Cd和Hg等8种重金属的全量,结果表明,8种重金属的平均浓度高于广东省土壤背景值。Cd和Hg的最高浓度和变异系数分别为6.54mg/kg、115%和4.82mg/kg、151%,暗示Cd和Hg的人为来源。多元统计与傅立叶和谱分析的结合,解释了Cr、Ni和Cu的自然来源,Pb、Zn、As、Cd和Hg的人为来源;傅立叶和谱分析进一步阐释了Zn与Cu的双重来源,并推断土壤Hg来源于大气沉降。研究区内大约21.7%的土壤受重金属污染,表明需要调整该区的农业生产活动。

In the Shunde Area of Foshan,Pearl River Delta Economic Zone,208 topsoil samples were collected from vegetable fields to measure the contents of copper,nickel,chromium,arsenic,lead,zinc,cadmium,and mercury. The results showed that the average concentration of all these eight heavy metals were higher than their background values of Guangdong Province. Coefficients of variation of Cd and Hg reached as high as 115% and 151% respectively,coupling with high concentrations,which suggested anthropogenic sources of these elements. Cr,Ni and Cu displayed low coefficients of variation,thus suggesting a major natural source. The combination of multivariate statistical and Fourier spectral analysis methods successfully identified the elements Pb,Zn,As,Cd and Hg from anthropogenic sources and Cr,Ni and Cu from natural source. Furthermore,Fourier spectral analysis not only interpreted the double sources of Zn and Cu,but also inferred that atmosphere deposition could be an important source of Hg enrichment in soil. According to the pollution evaluation,21.7 percent of the study area is suffered from moderate and severe pollution,indicating the requirement of modifications in agricultural cultivation practices in these areas.