Fate and Transport of Viruses in Porous Media

Microbiological contaminants (e.g., bacteria, protozoa, and viruses) pose one of the greatest risks in water resources. About 70% of the waterborne microbial illness outbreaks in the United States has been associated with groundwater. Although viruses are not the only pathogens known to contaminate groundwater, they are much smaller in size than bacteria or protozoan cysts and are not filtered out to the same extent in the porous soil matrix. Knowledge of the factors that influence the fate and transport of viruses in soil and aquifers is critical to making accurate determinations of groundwater vulnerability and to developing regulations that are protective of public health. In this paper, we review the current state of knowledge on fate and transport of viruses in porous media which include (i) mechanisms and modeling of virus sorption, (ii) virus survival and factors affecting virus inactivation in the natural environment, and (iii) mechanisms of virus transport in porous media and available modeling approaches. Because viruses are surrounded by a protein capsid and are expected to behave similarly to proteins, an overview on the mechanisms of protein sorption and denaturation is also provided. Factors such as solution chemistry, virus properties, soil properties, temperature, association with solid particles, and water content have been found to influence virus sorption, survival, and transport in porous media. A review of protein literature provides some insights as to what mechanism might be involved in virus sorption that have so far not been studied. Some needs for future research are suggested.