Transport of avian infectious bronchitis virus (IBV) and bacteriophage (MS2) in saturated porous media

Retention and transport of microbial pathogens such as viruses in the subsurface environment is an important public health concern. The objectives of this study include: 1) evaluate the transport potential of the avian infectious bronchitis virus (IBV), which is a good surrogate for the virus that causes Severe Acute Respiratory Syndrome (SARS) and 2) examine the effect of solution ionic strength on the retention and transport of bacteriophage MS2, which is a commonly used model for human enteric viruses. Column experiments using either glass beads (IBV) or sand (MS2) were conducted under steady-state and saturated water flow conditions, and for MS2, at a wide range of ionic strength from 0.002 to 0.163mol/L. IBV was retained via first-order removal with a rate coefficient of 0.18h-1 when transported through the glass beads under the conditions examined in this study. Transport of MS2 was shown to strongly depend on ionic strength. The first-order removal rate coefficient was found to increase with increasing ionic strength from 0.002 to 0.065mol/L (first critical value), decrease when ionic strength was further increased to 0.08 mol/L (second critical value), and then increased slowly again when the ionic strength exceeded 0.080mol/L. The reasons for the existence for such critical ionic strength values are not clear at the present. IBV reacted more strongly with porous media and was retained more than MS2 under the same ionic strength and pH, indicating that MS2 may also be used as a conservative model for IBV and perhaps also the SARS virus.