| The prevalence of adenovirus (AdV) in fecal-related materials has been recognized by the scientific community and numerous studies have reported the presence of human adenoviruses (HAdV) in the water environment. One of the major reservoirs of AdV in the environment is solid material such as biosolids and manure. However, the quantitative levels and fate of HAdV in land applied waste such as manure and biosolids is still poorly understood. The overall objective of this study is to quantify adenovirus and other virus levels in land applied solid materials (biosolids, manure) and develop an understanding of the factors influencing the transport and sorption of biosolid-associated viruses, particularly HAdV.Among five different enteric viruses tested in this study, HAdV had the highest concentration and occurrence in the mesophilic anaerobic digested (MAD) biosolids. The infectious HAdV was also more prevalent than the infectious enterovirus. Bovine adenovirus (BAdV) was detected frequently in manure samples however, the occurrence and quantitative levels of BAdV were lower than bovine polyomavirus (BPyV), and a high genetic diversity was observed in the BAdV isolated from different samples. These results suggest that biosolids are the major reservoir of HAdV and a more vigorous sludge treatment may be needed to avoid the risk of water contamination by enteric viruses at the land application site. Also, BAdV may be less suitable than BPyV as bovine fecal indicator due to its lower prevalence and higher genetic diversity.Despite the high loads of HAdVs observed in biosolids, no indigenous viruses (HAdV and somatic phage) were observed in any of the leachate (lysimeter effluent) samples in a large-scale field experiment, which indicate that the sandy-loam soil system described in this study could effectively remove/sorb the biosolid-associated pathogens. P-22 bacteriophage (microbial tracer) was found in leachate samples collected from three of the lysimeters with a breakthrough occurring at less than 1.0 pore volume, and early breakthrough indicates that preferential flow plays a critical role in virus transport in subsurface. A first order decay model was fit to the measurements of somatic phage and P-22 in the surface water samples and results indicate the biosolid-associated viruses could survive up to ten days after land application.Based on the Freundlich constants obtained from isotherm curves, both bonded organic matter (OM) and dissolved OM (DOM) inhibited the sorption of HAdV to soil, and soil with higher OM also enhanced desorption of HAdV. A series of experiments provided evidence that the loss of virus in the polyethylene (PE) vials was due to sorption rather than inactivation, and similar to soil, the sorption of HAdV to polyethylene (PE) was inhibited by DOM. Glass containers are preferable to containers made with plastic materials such as PE for HAdV-soils sorption experiment since the sorption of HAdV was significantly reduced in glass tubes. The overall results suggested that OM plays an important role on sorption and desorption of HAdV. |
