通过砂柱试验模拟BTEX(苯、甲苯、乙苯和二甲苯的混合物)污染含水层的过程,分析了含水层中铁形态分布及氧化还原环境的变化.结果表明:发生铁还原反应区域介质中的w(TFe)降幅最大,达25.7％；而发生硫酸盐还原反应的区域介质中的w(TFe)因亚铁沉淀生成作用降幅减至11.7％ ～ 14.6％.铁还原菌电子受体主要来源于氧化物结合态铁；氧化物结合态铁首先转化为可交换态铁,进而被利用.硫化物结合态铁的形成可作为硫酸盐还原过程开始的标志.%A lab-scale column was constructed to investigate the pollution process of an aquifer by BTEX ( mixture of benzene, toluene, ethyl-benzene and xylenes ). Variations of iron species and redox environments were analyzed, in order to clarify the biogeochemical process of iron reduction. The experimental results indicated that the total iron content decreased in the iron reduction zone, with the maximum decreasing extent reaching 25. 7% . The total iron content decreased less in the sulfate reduction zone due to the precipitation of ferrous iron,with the decreasing extent being 11. 7% -14. 6% . Oxides combined iron, which was transformed to exchangeable iron first and then utilized by microbes, were the dominant electron acceptor sources for iron reduction bacteria. The formation of ferrous sulfide could serve as an indicator of the beginning of sulfate reduction.
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