不同温度带多氯联苯土壤残留特征的数值模拟

Numerical simulation on residue characteristics of polychlorinated biphenyls in soil in different temperature zones

为了解多氯联苯(PCBs)在不同温度带的环境分布行为及特征,采用ChnGIPERM(Chinese gridded industrial pollu-tants emission and residue model)模型,对PCB同系物单源以相同排放量向大气排放,进行了土壤残留特征的数值模拟,并根据不同温度带选取相应的受体点,进行环境分布行为及特征的分析研究.研究结果表明,PCB同系物在土壤中的残留量与离污染源的距离、理化性质及气象条件有关,随着距离的增大土壤残留浓度降低,气象条件会影响多氯联苯的分布状况.PCB同系物从土壤中的挥发与具有较强温度依存性的蒸汽压有关,低氯取代的PCB同系物因其蒸汽压大于高氯取代的PCB同系物,易于从土壤中挥发而导致其土壤中的残留量迅速降低.[OH]降解速率系数随着氯原子数的增多而降低,从而使长距离迁移过程中,高纬度地区随着氯原子数的增多而使PCBs土壤中的含量增高.

In an effort to understand environment distribution and characteristics of polychlorinated biphenyls（PCBs） in different temperature zones,Chinese gridded industrial pollutants emission and residue model（Chn GIPERM） was employed to model the residues characteristics of PCBs in soil,caused by emissions of a single PCB source.Receptor sides were also selected utilizing different temperature zones,for the purpose of conducting analysis of environment distribution behavior and characteristics of PCBs.The results illustrate that the residues quantity of PCBs in soil was related to the distance from the pollution source,physical and chemical properties and meteorological condition.The residue concentration decreased with the increase of distance,and the physic-chemical properties of PCBs and the meteorological condition also affected the distribution.The strong temperature dependence of vapor pressure affects the rate of evaporation from soil of PCBs.The vapor pressure of light PCBs is larger than heavy PCBs,so the light PCBs can easily evaporate from soil,which results in the residue concentration rapidly decreasing.The degradation rate constant hydroxyl radicals decreased with the increase of the number of chlorine atoms,so that in the process of long-range atmospheric transport,the residue concentration of PCBs in soil increased with the increase of the number of chlorine atoms in the high latitude region.