土柱模拟研究氯代烃在土壤包气带中的垂向迁移-环境科学研究.DOC

土壤包气带含水率对氯代烃垂向迁移影响的1,2，杨 兵2，秦普丰1，刘寒冰2，薛南冬2* 1.湖南农业大学资源环境学院，湖南 长沙 4101282 2.中国环境科学研究院，北京 100012 摘要：挥发性有机物通过土柱模拟，研究土壤包气带含水率对不同氯代烃TCE（三氯乙烯、四氯乙烯）气相扩散速率的影响。结果表明，土壤含水率与氯代烃气相扩散显著负相关=-0.89，P0.01，n=7（TCE）=-0.86，P0.01，n=7（PCE）〕土壤含水率0.5%增至%，TCE气相有效扩散系数0.0359 cm2/s降至0.0cm2/s，平衡时间由13 h增至91 h，平衡时气体浓度由4.22 g/m3降至0.31 g/m3；PCE气相有效扩散系数cm2/s降至0.0cm2/s，平衡时间由15 h增至103 h，平衡时气体浓度由3.01 g/m3降至0.12 g/m3。与Penman模型、Marshall模型模拟值相比，氯代烃气相有效扩散系数实测值与Millington-Quirk模型模拟值拟合程度更好（R0.95，P0.01，n=7）。研究显示，土壤包气带含水率的增加对氯代烃气相扩散有明显的抑制作用。 关键词：含水率三氯乙烯；四氯乙烯；垂向迁移Millington-Quirk模型X53 Effect of Moisture Content on the Vertical Migration of Chlorinated Hydrocarbons in Soil Unsaturated Zone LONG Yu1,2, YANG Bing2, QING Pufeng1, LIU Hanbing2, XUE Nandong2 1.College of resources and Environment, Hunan Agricultural University, Changsha 410128, China 2.Chinese Research Academy of Environmental Sciences, Beijing 100012, China Abstract: The vertical migration of chlorinated hydrocarbon in soil is an important way leading to a risk of inhalation exposure to volatile organic compounds. Serial soil column experiments have been developed to investigate the vertical migration of chlorinated hydrocarbons. The effect of moisture content in soil unsaturated zone on the diffusion rate of chlorinated hydrocarbons (Trichloroethylene, TCE and Tetrachloroethylen, PCE) was studied, and a prediction model of effective vapor diffusion coefficient was optimized by linear fitting. The results showed that moisture content in soil was significantly negative correlated with the effective vapor diffusion coefficient of chlorinated hydrocarbons (R=-0.89, P0.01, n=7(TCE); R=-0.86, P0.01, n=7(PCE)). With the moisture content increased from 0.5% to 40.0%, the effective vapor diffusion coefficient of TCE(DT) decreased from 0.0359 cm2/s to 0.0025 cm2/s, equilibrium time increased from 13 h to 91 h and the equilibrium vapor concentration decreased from 4.22 g/m3 to 0.31 g/m3; while the effective vapor diffusion coefficient of PCE(DP) decreased f