Submitted to: Environmental Science and Technology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/25/2006
Publication Date: 8/9/2006
Citation: Bradford, S.A., Tadassa, Y.F., Jin, Y. 2006. Transport of coliphage in the presence and absence of manure suspension. Environmental Science and Technology. VOL 35:1692-1701 Interpretive Summary: Groundwater contamination by disease causing viruses is common in many areas of the United States. Although most waterborne viruses are of fecal origin, knowledge of the processes that control the transport and fate of viruses in the presence of manure contam-inated water is still incomplete. Results from this study indicate that the survival of viruses may be enhanced in the presence of dissolved manure, and that virus transport studies conducted with pure solutions may significantly underestimate the migration potential of viruses in manure contaminated environ-ments. Conversely, manure contamination was also found to increase the retention of viruses in the soil by filling and/or clogging small soil pores. Information on virus fate is needed to assess the risk and vulnerability of water resources to pollution, and to develop cost-effective treatment strategies to minimize human and animal exposure.
Technical Abstract: Mechanisms of coliphage (PhiX174 and/or MS2) transport and fate in the presence and absence of manure suspension were studied in saturated column experiments. In the presence of manure suspen-sion, little inactivation occurred and the transport was con-trolled by deposition. The deposition followed a power law distribution with depth, and the magnitude increased with decreas-ing sand size. Comparison of the cumulative size distribution of manure components in the suspension initially and after passage through sand, suggested that particles retained by mechanical filtration decreased the effective pore size and potentially induced straining of PhiX174. A 2-site kinetic deposition model was used to estimate the magnitudes of attachment and straining in the presence of manure suspension, and provided a good description of the data. Modeling results indicated that straining accounted for 16-42% percent of the deposited PhiX174, and that both straining and attachment increased with decreasing sand size due to smaller pores and higher surface area, respectively. In the absence of manure suspension, PhiX174 and MS2 transport was controlled by inactivation induced by the solid phase. This conclusion was based upon comparison of coliphage transport behavior at 5 and 20 deg C, mass balance information, and numerical modeling. Comparison of PhiX174 transport data in the presence and absence of manure suspension revealed much higher effluent concentrations in the presence of manure. This difference was attributed to lower inactivation and higher detachment rates. The observed coliphage transport behavior suggests that viability of viruses may be enhanced in the presence of manure suspensions, and that transport studies conducted in the absence of manure suspension may significantly underestimate the transport potential of viruses in manure contaminated environments.