Physicochemical Factors Influencing the Preferential Transport of Escherichia coli in Soils
Physicochemical Factors Influencing the Preferential Transport of Escherichia coli in Soils
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DOI：
10.2136/vzj2013.07.0120
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发表时间：
2014-01
影响因子：
2.8
通讯作者：
Yusong Wang;S. Bradford;J. Šimůnek
中科院分区：
文献类型：
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作者：
Yusong Wang;S. Bradford;J. Šimůnek
在不同离子强度条件下，对大肠杆菌D21g在具有人工大孔的优先流动体系中的转运和释放进行了实验室和数值研究。大孔是通过将粗砂透镜嵌入细砂基质中，并改变透镜的长度、连续性和垂直位置而产生的。人工大孔的长度被证明对大肠杆菌D21g的优先运输有很大的影响，特别是在高IS条件下。不连续的大孔（被细砂打断）比相同长度的连续大孔（向顶部或底部边界开放）对大肠杆菌D21g的转运更不有利。在低IS条件下，大肠杆菌D21g比Br -在优先路径上更广泛的运输和更早的到达时间，这是由于尺寸排除的结果。对于开放至顶边界或底边界的大孔流动系统，在溶液IS减小后观察到两个释放脉冲（一个来自优先路径，另一个来自矩阵），而对于具有不连续大孔的系统，观察到三个脉冲（两个来自优先路径，另一个来自矩阵）。在恒定和瞬态溶液化学条件下，大肠杆菌D21g的数值模拟与实验数据的一致性非常高，除了它们能够预测不同透镜结构之间输运的一些细微差异。
Laboratory and numerical studies were conducted to investigate the transport and release of Escherichia coli D21g in preferential flow systems with artificial macropores under different ionic strength (IS) conditions. Macropores were created by embedding coarse sand lenses in a fine sand matrix and altering the length, continuity, and vertical position of the lens. The length of an artificial macropore proved to have a great impact on the preferential transport of E. coli D21g, especially under high‐IS conditions. A discontinuous macropore (interrupted by fine sand) was found to have less preferential transport of E. coli D21g than a continuous macropore of the same length that was open to either the top or bottom boundary. At low IS, more extensive transport in the preferential path and earlier arrival time were observed for E. coli D21g than Br− as a result of size exclusion. Two release pulses (one from the preferential path and the other from the matrix) were observed following a reduction of the solution IS for flow systems with macropores that were open to either the top or bottom boundary, whereas three pulses (two from the preferential path and another from the matrix) were observed for systems with discontinuous macropores. Numerical simulations of E. coli D21g under both constant and transient solution chemistry conditions had very high agreement with the experiment data, except for their capability to predict some subtle differences in transport between the various lens configurations.