Virus Transport through Saturated Sand Columns as Affected by Different Buffer Solutions

Abstract

To accurately examine the mechanisms that control virus retention and transport in porous media, it is essential to perform experiments under environmentally relevant conditions. Laboratory studies of virus transport are generally conducted using buffered solutions. However, there are no standards for the concentration and composition of the solution, making comparisons between different studies difficult. Our objective was to systematically investigate the effects of the ionic strength and composition of buffer solutions on adsorption of viruses during transport through saturated sand columns. Two phosphate buffered saline solutions (PBS and PBS2) and one artificial ground water (AGW) were used and experiments were conducted under saturated, steady state flow conditions. Bromide tracer and bacteriophages φX174 and MS‐2 were introduced into saturated sand columns as step inputs and their concentrations in the outflow samples were determined. Change in ionic strength did not affect the behavior of φX174, whereas MS‐2 was largely removed in the high ionic strength PBS buffer (0.16 M) but moved through the columns in the low ionic strength PBS2 and AGW buffers (0.002 2M). An additional experiment conducted under an ionic strength gradient (from 0.002 to 0.2 M) using PBS indicated that the outflow concentration of MS‐2 decreased slowly from an ionic strength of ∼0.03 M, reached a minimum at an apparent critical value of ∼0.1 M, and then increased gradually. This study also suggests that metals or metal oxides on sand surfaces can cause significant virus removal under high ionic strength conditions.

Processes in Pathogenic Biocolloidal Contaminants Transport in Saturated and Unsaturated Porous Media: A Review

“…The physical processes such as advection, dispersion, diffusion, straining and physical filtration, adsorption and biological processes such as growth/ decay processes and include active adhesion/detachment, survival and chemotaxis are strongly affected on biocolloid transport in saturated and unsaturated porous media. Although there is a substantial body of published research on biocolloidal transport in the subsurface, much of it focuses on transport in the saturated zone (e. g. Bales et al 1989;Chu et al 2000;Chu et al 2001;Fontes et al 1991;Harvey 1997;Hornberger et al 1992;McCarthy and McKay 2004;McKay et al 1993;Sen and Khilar 2006;Sen and Khilar 2009;Sen et al 2004) rather than on transport in the unsaturated vadoze zone. In the unsaturated porous media, the additional mechanisms (compared with saturated zone) for colloid transport are reported as: colloid captured at the liquid-gas interface (Crist et al 2004;2005;Gao et al 2008;Zevi et al 2005), colloid capture due to straining (Wan and Tokunaga 1997;Bradford et al 2006, colloid captured at solid-liquid-gas interface (Williams and Berg 1992;Abdel-Fattah and El-Genk 1998;Sirivithayapakorn and Keller 2003;Lazouskaya and Jin 2006) and colloid storage in immobile zone (Cherrey et al 2003;Gamerdinger and Kaplan 2001;Gao et al 2006), respectively.…”

Review on subsurface colloids and colloid-associated contaminant transport in saturated porous media

“…McCarthy and McKay [18] and Sen et al [122] mentioned in their article that there is a substantial body of published research on microbial transport in the subsurface, much of it focuses on transport in the saturated zone [119][120][121][122][123][124][125][126][127][128][129][130][131][132][133][134]. Transport of bacteria in porous media is mainly bounded with small scale batch and column studies.…”

Relative transport of human adenovirus and MS2 in porous media

“…Previous studies found the breakthroughs of MS2 were more retarded [20] and recoveries of MS2 were lower [21] under higher IS conditions. However, the attachment of different viruses may respond differently to IS, for example, the recovery of X174 remained the same in higher IS buffer [21].…”

“…Ionic strength (IS) is known to have significant influence on microbial and virus transport behaviors [19][20][21][22] and a wide range of IS is present in different environmental waters such as rivers, lakes, estuaries and oceans. Previous studies found the breakthroughs of MS2 were more retarded [20] and recoveries of MS2 were lower [21] under higher IS conditions.…”