渗滤液污染包气带中铁的形态变化

从渗滤液场龄和包气带岩性两方面出发，研究了新、老渗滤液对亚粘土和细砂包气带环境中Fe的含量及存在形态的影响。结果表明：新、老渗滤液分别能使细砂包气带介质中除残渣态以外Fe的含量增加16.68%或降低13.82%。亚粘土比细砂作为包气带介质更能缓冲渗滤液对介质中Fe的影响程度，其受影响范围在包气带0～20 cm深度处。当亚粘土为介质的包气带被新渗滤液污染后，其表层介质中碳酸盐结合态Fe的含量会增加15倍之多，为缓冲渗滤液Fe的污染做出了巨大贡献，但这部分Fe的存在也是潜在的二次污染源，在环境pH急剧变化的情况下，它可能会引起地下水高铁污染。

Variation of Fe speciation in the vadose zone polluted by landfill leachate

Changes of Fe content and speciation in the sub-clay and fine sand vadose zone were studied in laboratory columns,which were polluted by acetigenic and methanogenic landfill leachate. Experimental results showed that the Fe content besides residual form of fine sand was increased 16.68% in the vadose zone after the pollution of acetigenic leachate,however decreased 13.82% contaminated by methanogenic leachate. Sub-clay did better than the fine sand in the vadose zone as buffer to trail off the contamination of leachate on Fe,just a-bove 20 cm area in the vadose zone was affected. When the sub-clay vadose zone was polluted by acetigenic leachate,the content of bound to carbonates Fe increased by 15 times,which made a huge contribution to buffer the Fe pollution of the leachate. On the other side it was also a potential source of the second pollution,when the pH changes rapidly it would arouse the high Fe content of groundwater.