Johnson & Ettinger模型和Volasoil模型在污染物室内挥发风险评价中的应用和比较

在土壤污染和地下水污染的现场,挥发过程是挥发性污染物暴露的重要途径.设置典型土壤污染场景作为研究对象,选取Johnson&Ettinger模型和Volasoil模型进行室内挥发过程的模拟和暴露浓度的计算.对两个模型中污染物的运移机理进行了比较和分析.尽管方法和参数选择有所不同,二者对污染源处三相平衡浓度的计算本质上是一致的.暴露浓度的计算结果表明,两个模型对室内挥发过程的模拟可能会有较大差异,与污染现场的具体情况有关.参数影响的分析表明,污染源顶部埋深对二者暴露浓度的影响一致,Johnson&Ettinger模型对污染土壤含水率的大小非常敏感.建议考虑房屋结构的实际情况,选用或者改进模型进行室内挥发过程的评价.

Comparative study on Johnson & Ettinger model and Volasoil model in the indoor volatilization risk assessment of contaminant

On soil or groundwater contamination site, volatilization is an important exposure pathway for volatile contaminant. Johnson & Ettinger model and Volasoil model were used to simulate indoor volatilization process and calculate contaminant concentrations in air on typical soil contamination site, and the migration mechanism of contaminant was analyzed. For the contaminant concentrations in three phases including volatile phase in soil gas, dissolved phase in moisture and sorption phase on soil grains at equilibrium status, two models are theoretically the same although the methods and parameters are different. However, the calculated indoor exposure concentrations due to volatilization were quite different between the two models. The depth of contamination had similar influence on the exposure concentrations for the two models. Johnson & Ettinger model was sensitive to the water content in soils. It was suggested to select or improve the model for indoor volatilization assessment based on the building structure.