The transport of human adenovirus, nanoparticles, and PRD1 and MS2 bacteriophages was tested in fine granular limestone aquifer material taken from a borehole at a managed aquifer recharge site in Adelaide, South Australia. Comparison of transport and removal of virus surrogates with the pathogenic virus is necessary to understand the differences between the virus and surrogate. Because experiments using pathogenic viruses cannot be done in the field, laboratory tests using flow-through soil columns were used. Results show that PRD1 is the most appropriate surrogate for adenovirus in an aquifer dominated by calcite material but not under high ionic strength or high pH conditions. It was also found that straining due to size and the charge of the colloid were not dominant removal mechanisms in this system. Implications of this study indicate that a certain surrogate may not represent a specific pathogen solely based on similar size, morphology, and/or surface charge. Moreover, if a particular surrogate is representative of a pathogen in one aquifer system, it may not be the most appropriate surrogate in another porous media system. This was apparent in the inferior performance of MS2 as a surrogate, which is commonly used in virus transport studies. A quantitative study of virus transport and removal in aquifer material in the laboratory is a useful first step to investigating field studies. This study compared the transport of human adenovirus (HAdV), a common virus that causes childhood diarrhea, in small columns of fine granular limestone with three different virus surrogates: PRD1 and MS2 bacteriophages and 100-nm carboxylated polystyrene nanoparticles. This was done to assess the suitability of the surrogates for further investigations, possibly in the field, and to establish preliminary attachment and detachment rates for the colloids in the aquifer material, as well as defining a preliminary removal rate.Human adenovirus from human fecal sources is present in surface water and groundwater, but its transport in groundwater has not yet been widely studied. Prevalent in urban stormwater runoff (Sidhu et al., 2012), HAdV was also detected in a large river and its watershed (Corsi et al., 2014) and has been found in groundwater (Futch et al., 2010), possibly leaking into the subsurface from sewage pipes (Bradbury et al., 2013). Because of its resistance to treatment such as chlorination and ultraviolet disinfection (Calgua et al., 2014;Rodriguez et al., 2008) and its persistence in sewage and treated water with a very long Journal of Environmental Quality MICROBIAL TRANSPORT AND FATE IN THE SUBSURFACE SPECIAL SECTION Core Ideas• Adenovirus was compared to three surrogates: 100-nm particles and MS2 and PRD1 bacteriophages.• Column tests were performed in experiments using fine granular limestone aquifer material.• Column experiments under variable chemical conditions have not been done before using adenovirus.• PRD1 bacteriophage was the best surrogate to model the attachment of adenovirus but not detac...

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Members of the genus Cryptosporidium are waterborne protozoa of great health concern. Many studies have attempted to find appropriate surrogates for assessing Cryptosporidium filtration removal in porous media. In this study, we evaluated the filtration of Cryptosporidium parvum in granular limestone medium by the use of biotin-and glycoprotein-coated carboxylated polystyrene microspheres (CPMs) as surrogates. Column experiments were carried out with core material taken from a managed aquifer recharge site in Adelaide, Australia. For the experiments with injection of a single type of particle, we observed the total removal of the oocysts and glycoprotein-coated CPMs, a 4.6-to 6.3-log 10 reduction of biotin-coated CPMs, and a 2.6-log 10 reduction of unmodified CPMs. When two different types of particles were simultaneously injected, glycoprotein-coated CPMs showed a 5.3-log 10 reduction, while the uncoated CPMs displayed a 3.7-log 10 reduction, probably due to particle-particle interactions. Our results confirm that glycoprotein-coated CPMs are the most accurate surrogates for C. parvum; biotin-coated CPMs are slightly more conservative, while unmodified CPMs are markedly overly conservative for predicting C. parvum removal in granular limestone medium. The total removal of C. parvum observed in our study suggests that granular limestone medium is very effective for the filtration removal of C. parvum and could potentially be used for the pretreatment of drinking water and aquifer storage recovery of recycled water. W aterborne cryptosporidiosis is mainly caused by Cryptosporidium parvum and Cryptosporidium hominis in humans (1). Cryptosporidium can be found in water contaminated with infected human or animal feces and has a low infectious dose, and ingestion of less than 10 oocysts can lead to infection (2). Cryptosporidium oocysts are sometimes detected in drinking water supplies (3) and in potable groundwater (4), causing disease outbreaks. For example, in the 1993 cryptosporidiosis outbreak in Milwaukee, WI, USA, about 400,000 people were infected and more than 100 people died after contamination of drinking water by C. parvum (5). More recently, a waterborne outbreak of cryptosporidiosis in Ö stersund, Sweden, which infected 27,000 people in 2010, was caused by C. hominis (6).C. parvum can survive in surface water and groundwater for a long period of time (7) and is resistant to chemical disinfection, like chlorination (8) and ozonation (9), due to its thick oocyst wall. UV irradiation with low-and medium-pressure lamps has been found to be effective at inactivating C. parvum (10). However, the efficacy of UV irradiation as well as that of chemical disinfection is hampered by turbidity in the water. Thus, filtration is often used as an essential primary step for drinking water treatment in the course of a multibarrier treatment system because it is effective and cost-efficient.Because it is extremely infectious and highly resistant to chlorination, testing for C. parvum is often used in risk analysis of drin...