Bacterial filtration rates in repacked and weathered soil columns

Safadoust, A.; Mahboubi, A.A.; Gharabaghi, Bahram; Mosaddeghi, Mohammad Reza; Voroney, Paul; Unc, Adrian; Sayyad, Gholamabbas

doi:10.1016/j.geoderma.2011.08.014

Cited by 20 publications

(21 citation statements)

References 39 publications

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“…5). The relation indicates that as the average pore water velocity increases, AgNPs filtration decreases, which is in agreement with Safadoust et al (2011) who reported that the filtration coefficient for E. coli in soil columns increased as a result of a reduced flow rate. The data points in Fig.…”

Section: Transport and Retention Of Agnps Through Saturated And Unsatsupporting

confidence: 91%

“…It is expected that much larger λ f values should be observed in natural soil columns compared with the homogenous sand columns. The key role of soil structure and texture in the transport and retention of particles has been demonstrated in several studies (e.g., Safadoust et al, 2011). However, in our study, λ f is not significantly affected by soil texture and saturation conditions (Table 4).…”

Section: Transport and Retention Of Agnps Through Saturated And Unsatsupporting

confidence: 57%

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Transport of silver nanoparticles in intact columns of calcareous soils: The role of flow conditions and soil texture

et al. 2018

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A B S T R A C TGrowing production of manufactured nanomaterials has increased the possibility of contamination of groundwater resources and soils by nanoparticles (NPs). It is crucial to study the fate of NPs in subsurface porous media in order to evaluate and control their risks to ecosystems and human health. Hence, this study was conducted to investigate the transport and retention of polyvinylpyrrolidone (PVP) stabilized silver nanoparticles (AgNPs, a diameter of 40 nm) under saturated and unsaturated conditions in intact columns of two calcareous sandy loam (TR) and loam (ZR) soils. Furthermore, similar experiments were conducted using sand quartz as a reference medium. A pulse of the AgNP suspension with an input concentration (C 0 ) of 50 mg L −1 was injected into the columns for 3 pore volumes. The transport of bromide (Br), as a non-reactive inert tracer, was also examined. High mobility of AgNPs was observed through the sand columns due to unfavorable conditions for AgNP deposition on the quartz sand surfaces. Nearly all AgNPs introduced into the columns of both soils were retained in the soil. Percentages of AgNPs leached out of the columns were < 1% of the total injected mass in both soils. Hyperexponential retention profiles (RPs) were observed in both soils and maximum concentrations of 100-130 mg kg −1 were determined near the columns' inlet. However, slightly stronger retention of AgNPs and greater maximum retained concentrations on the solid phase (S max ) in the ZR soil compared with the TR soil may be attributed to smaller grain sizes of the ZR soil. Hydrodynamic forces adjacent to the solid surfaces near the column inlet can provide a viable explanation for the hyperexponential shape of RPs. The one-site kinetic attachment model in HYDRUS-1D, which accounted for time-and depth-dependent retention, was successfully used to analyze the retention of AgNPs. The results showed that the degree of saturation had little effect on the mobility of AgNPs through undisturbed soil columns. Our results suggested the limited transport of AgNPs in neutral/alkaline calcareous soils under both saturated and unsaturated conditions.

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Section: Transport and Retention Of Agnps Through Saturated And Unsatsupporting

confidence: 91%

Section: Transport and Retention Of Agnps Through Saturated And Unsatsupporting

confidence: 57%

Transport of silver nanoparticles in intact columns of calcareous soils: The role of flow conditions and soil texture

et al. 2018

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“…There were no significant differences in the performance of the soil in filtering E. coli between the drip irrigated system with canal water and furrow irrigated treatment with canal water. The soil filtering described here is for lateral flow of water, in some ways analogous to previous published research on soil filtering of bacteria under vertical flow of water in soil and water columns (Jamieson et al, 2002;Unc and Goss, 2004;Mankin et al, 2007;Semenov et al, 2009;Safacoust et al, 2011Safacoust et al, , 2012. Regardless of initial counts, concentrations were typically highest near the drip tape for SDI or water's edge of furrow irrigation, lower at the points halfway between the drip tape/furrow and onion bulbs, and lowest at spots adjacent to the onions.…”

Section: Soil Filtration Of E Colimentioning

confidence: 58%

“…Semenov et al (2009) found limited E. coli movement in the field beyond the application layer with surface application of E. coli. Recovery rates of E. coli from water flowing through soil columns were tested for two different soil types, two different flow rates, and two different methods of preparing the soil for the columns (repacked or physically and biologically weathered) (Safacoust et al, 2011). In all eight instances, the E. coli recovery diminished with increasing soil depths of 15, 30, and 45 cm.…”

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confidence: 99%

Drip vs. Furrow Irrigation in the Delivery of Escherichia coli to Onions

Shock¹,

Reitz²,

Roncarati³

et al. 2016

Appl. Eng. Agric.

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“…Therefore a solution spreader (mini column with the diameter as the same as soil column and the high of 10 cm) was placed on soil columns to spread the bromide solution (hydraulic head) on the soil columns ( Figure 1). A gentle suction was created by a vacuum pump on the bottom of the single grain (0.3 ± 0.05 hPa) and prismatic (0.1 ± 0.05 hPa) columns due to their low conductivity in order to avoid water accumulation at the lower boundary of the columns and to ensure a steady-state flow condition (Mosaddeghi et al 2009;Safadoust et al 2011Safadoust et al , 2012aSafadoust et al , 2012b. It was necessary to increase the pressure gradient to compensate for the lower hydraulic A c c e p t e d M a n u s c r i p t conductivity of these columns, resulting in similar flow rate.…”

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confidence: 99%

Comparison of three models describing bromide transport affected by different soil structure types

Safadoust

Khaboushan

Mahboubi

et al. 2015

Archives of Agronomy and Soil Science

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This study was conducted to investigate the effects of soil structure on bromide transport through three soils with granular, prismatic, and single-grain structures. The breakthrough curve (BTC) of the single-grain structure was sigmoidal, symmetrical and similar to a piston flow, showing the dominance of mass flow. In contrast, the BTCs of the granular and prismatic structures were initially steep, becoming more gradual at high pore volumes (PVs). The stable structure and preferential pathways caused the early breakthrough of BrP P in the leachate of these columns. The convection dispersion equation (CDE), mobile-immobile water (MIM), and dualpermeability (DP) models were fitted to observed data using the program HYDRUS-1D. The equilibrium transport model (CDE) was not as successful as non-equilibrium (MIM and DP) models in describing the Br transport in prismatic and granular soil columns, although it was able to describe the Br transport in single-grain column well. Overall the results demonstrated the importance of soil structure in pollutant transport through soils. Downloaded by [University of Otago] at 12:08 17 July 2015A c c e p t e d M a n u s c r i p t

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Bacterial filtration rates in repacked and weathered soil columns

Cited by 20 publications

References 39 publications

Transport of silver nanoparticles in intact columns of calcareous soils: The role of flow conditions and soil texture

Transport of silver nanoparticles in intact columns of calcareous soils: The role of flow conditions and soil texture

Drip vs. Furrow Irrigation in the Delivery of Escherichia coli to Onions

Comparison of three models describing bromide transport affected by different soil structure types

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