Sorption of hydrophobic pollutants such as polynuclear aromatic hydrocarbons (PAHs) to soil and aquifer materials can severely retard their mobility and the time course of their removal. Because mobile colloids may enhance the mobility of hydrophobic pollutants in porous media and indigenous bacteria are generally colloidal in size, bacterial isolates from soil and subsurface environments were tested for their ability to enhance the transport of phenanthrene, a model PAH, in aquifer sand. Batch isotherm experiments were performed to measure the ability of selected bacteria, including 14 isolates from a manufactured gas plant waste site, to sorb 14C-phenanthrene and to determine whether the presence of the suspended cells would reduce the distribution coefficient (Kd) for phenanthrene with the sand. Column experiments were then used to test the mobility of isolates that reduced the Kd for phenanthrene and to test the most mobile isolate for its ability to enhance the transport of phenanthrene. All of the isolates tested passively sorbed phenanthrene, and most but not all of the isolates reduced the Kd for phenanthrene. Some, but not all, of those isolates were mobile in column experiments. The most mobile isolate significantly enhanced the transport of phenanthrene in aquifer sand, reducing its retardation coefficient by 25% at a cell concentration of approximately 5 x 10(7) ml-1. The experimental results demonstrated that mobile bacteria may enhance the transport of PAHs in the subsurface.
展开▼
机译：疏水性污染物（例如多核芳香烃（PAHs））吸附到土壤和含水层材料上会严重阻碍其流动性和去除时间。由于可移动的胶体可增强疏水性污染物在多孔介质中的流动性，并且原生细菌的大小通常为胶体，因此测试了从土壤和地下环境中分离出的细菌增强在水层砂中菲（一种PAH模型）的迁移能力。进行批量等温线实验以测量所选细菌（包括来自人工煤气厂废物场所的14种分离物）吸附14C菲的能力，并确定悬浮细胞的存在是否会降低菲的分配系数（Kd）。沙子。然后，使用柱实验来测试降低Kd菲的分离物的迁移率，并测试流动性最强的分离物增强菲转运的能力。所有分离物均测试了被动吸附的菲，大多数但并非全部分离物均降低了菲的Kd。这些分离物中的一些（但不是全部）在色谱柱实验中可以移动。最具流动性的分离物显着增强了菲在含水层砂中的运输，在细胞浓度约为5 x 10（7）ml-1时，其阻滞系数降低了25％。实验结果表明，可移动细菌可能会增强地下PAHs的运输。
展开▼
