Pathogenic bacteria, widely present in septic tanks, sewage sludges, and wastewater, can move through the subsurface environment to pollute drinking water. Bacterial transport behaviors vary with soil properties and are subject to soil pore networking. In this study, we investigated the transport of Escherichia coli 652T7 through intact and disturbed soils collected from different soil depths (0−5 cm, 5−10 cm, 10−15 cm, and 15−20 cm). The results obtained under steady-state saturated flow conditions demonstrated significant influences of soil depth and soil structure on the transport of E. coli 652T7. The breakthrough percentages of E. coli 652T7 from the intact soil cores increased with soil depth from 36 % at 0−5 cm to 63 % at 5−10 cm, 83 % at 10−15 cm, and 100 % at 15−20 cm. A similar trend was observed for the breakthrough from the repacked soil cores except with lower percentages (i.e., 16 % at 0−5 cm, 49 % at 5−10 cm, 76 % at 10−15 cm, and 86 % at 15−20 cm). Such an increase with soil depth was attributed to a combined effect of decreases in soil organic matter content (from 3.84 % to 2.47 %), free iron oxides (from 142.25 mg kg⁻¹ to 110.66 mg kg⁻¹), and zeta potential (from −17.6 mV to −29.0 mV) with soil depth. The larger breakthrough percentages of E. coli 652T7 from the intact than the repacked soil cores are speculated due to the existence of larger macropores, lower pore connectivity density, and reduced access to attachment sites in the intact soils than in the disturbed soils. Overall, this study suggests that tillage and organic amendments might be effective measures for reducing bacterial movement in soils.

在化粪池，污水污泥和废水中广泛存在的致病细菌可以穿过地下环境污染饮用水。细菌的运输行为随土壤特性而变化，并受土壤孔隙网络的影响。在这项研究中，我们调查了从不同土壤深度（0-5厘米，5-10厘米，10-15厘米和15-20厘米）收集的完整且受干扰的土壤中大肠杆菌652T7的运输。在稳态饱和流动条件下获得的结果表明，土壤深度和土壤结构对大肠杆菌652T7的运输具有重大影响。大肠杆菌的突破百分比完整土壤芯的652T7随着土壤深度的增加而增加，从0-5 cm的36％增至5-10 cm的63％，10-15 cm的83％和15-20 cm的100％。从重新包装的土壤岩心中发现的突破具有相似的趋势，但百分比较低（例如，在0-5 cm处为16％，在5-10 cm处为49％，在10-15 cm处为76％，在15-cm处为86％ 20厘米）。这种随土壤深度的增加归因于土壤有机质含量（从3.84％降低到2.47％），游离氧化铁（从142.25 mg kg ^-1到110.66 mg kg ^-1）和zeta电位（从-17.6 mV到-29.0 mV）。大肠杆菌的突破率更高推测从完整的土壤核心到重新包装的652T7的原因是，与受干扰的土壤相比，完整土壤中存在较大的大孔，较低的孔隙连通性密度和较少的附着点。总的来说，这项研究表明耕作和有机改良可能是减少土壤中细菌运动的有效措施。