黄土掺混下pH、有机质与南方农业土壤重金属含量的相关性分析

Correlation Analysis between pH and Organic Matter and Heavy Metal Content in Southern Agricultural Soil

摘要: 为能更好的了解北方黄土掺混下对南方农业土壤重金属污染的消减情况，本试验拟以甘肃省定西市自然黄土与湖南省长沙市芙蓉区重金属污染土壤为研究对象，设置两种土壤不同质量比例，分别测定土壤pH、有机质含量与重金属Cd、Hg、Pb、Cr和As元素的全量及有效态含量，对土壤污染情况进行分析评估并探讨三者与有效态含量间的相关性。研究结果显示：(1) 湖南芙蓉区农业土壤重金属污染情况为：主要受到镉、铅和汞重金属元素的污染，其中以铅超标最为严重，三种重金属已经超过了对环境的要求，须采取必要管控措施。(2) 土壤pH值、有机质含量与重金属有效态含量之间的关系：pH与有效态Cd、Pb含量呈极显著负相关，与有效态Hg、Cr和As之间无明显相关性。SOM与有效态Cd、Pb和As含量呈明显的正相关，与有效态Hg和Cr间相关性不明显。(3) 土壤重金属Cd、Pb全量与其有效量间呈极显著正相关关系，Hg全量与其有效量间呈显著正相关，而Cr、As全量与其有效量的相关性为不显著。利用北方黄土掺混消减超标重金属的修复方法可为今后开展重金属污染修复工作提供基础的科学依据。

Abstract: In order to better understand the reduction of heavy metal pollution in agricultural soil in southern China under the mixing of northern loess, this experiment intends to take the natural loess in Dingxi City, Gansu Province and the heavy metal-polluted soil in Furong District, Changsha City, Hu-nan Province as the research object, sets up different mass ratios of the two soils, determines the soil pH, organic matter content and the full and effective state content of heavy metals Cd, Hg, Pb, Cr and As elements, analyzes and evaluates the soil pollution and explores the correlation between the three and the effective state content. The results of the study show that: (1) The heavy metal pollu-tion of agricultural soil in Furong District, Hunan Province is mainly contaminated by cadmium, lead and mercury heavy metal elements, of which lead exceeds the standard is the most serious, and the three heavy metals have exceeded the environmental requirements, and necessary control measures must be taken. (2) Relationship among soil pH value, organic matter content and heavy metal effective state content: pH is negatively correlated with effective Cd and Pb content, and there is no obvious correlation between pH and effective Hg, Cr and As. SOM was positively correlated with the effective states Cd, Pb and As, but not with the effective Hg and Cr. (3) There was a significant positive correlation between the total amount of soil heavy metals Cd and Pb and their effective amount, the correlation between the total amount of Hg and its effective amount was significantly positive, while the correlation between the total amount of Cr and As and their effective quantity was not significant. The remediation method of using northern loess mixing to reduce excessive heavy metals can provide a basic scientific basis for the future remediation of heavy metal pollution.