不同土壤类型多氯联苯土壤残留特征变化分析

Residual Polychlorinated Biphenyls Characteristics Analysis of Different Soil Types

为了解多氯联苯(PCBs)在不同土壤类型中的环境分布行为,在'中国网格化农药排放残留模型'的基础上,开发了'中国网格化工业污染物排放残留模型',并用以对PCBs的研究。进行了PCBs的单源排放和包括城市土壤、旱田、水田、草地、林地及荒地等6种不同类型的土壤残留特征的数值模拟,并对土壤残留特征的变化进行了分析。研究结果表明:PCBs在土壤中的残留浓度与土壤的含气和含水率及其理化性质有关,对排放期末6种类型土壤质量分数与土壤含水体积作相关分析,其相关系数为R=-0.999 5,显著性水平P<0.000 1;PCB同系物在不同土壤层的残留浓度的变化与其理化性质有关。低氯取代的PCB同系物由于其水溶解度高,更容易向深层土壤迁移,其在土壤纵向分布随时间变化较快;随着土壤深度的增加,高氯取代的PCB同系物向深层土壤的扩散能力较弱,其在土壤纵向分布较为稳定。

In order to understand the environment distribution of polychlorinated biphenyls（PCBs） in soil,Chinese gridded industrial pollutants emission and residue model（ChnGIPERM） was developed based on ChnGPERM（Chinese gridded pesticide emission and residue model）,which has been used to study environmental behavior of PCBs in soil.Characteristics of PCBs in different types of soil,including urban soil,dry soil,paddy,grass,forest and uncultivated soil,contaminated by emissions of a single PCB source were investigated.The results showed that,the residue concentration of PCBs in soil depends on contents of air and water in soil,as well as the physic-chemical properties of PCBs,the correlation between quality fractions and contents of water in soil was pretty high（R=-0.999 5,P0.000 1）.With the increasing soil depth,the residue concentrations decrease with higher chlorine content in PCBs.Because of the higher water solubility,PCBs that contains less chlorine enters soil more easily,and their vertical distributions in soil change fast with time,while PCBs containing more chlorine have weaker abilities to diffuse in soil,and their vertical distributions in soil are quite stable with time.