More than 50% of the outbreaks of waterborne disease in the United States are due to the consumption of contaminated groundwater. An estimated 65% of the cases in these outbreaks are caused by enteric viruses. Little, however, is known about the persistence of viruses in groundwater. The purpose of this study was to determine whether measurable chemical and physical factors correlate with virus survival in groundwater. Groundwater samples were obtained from 11 sites throughout the United States. Water temperature was measured at the time of collection. Several physical and chemical characteristics, including pH, nitrates, turbidity, and hardness, were determined for each sample. Separate water samples were inoculated with each of three viruses (poliovirus 1, echovirus 1, and MS-2 coliphage) and incubated at the in situ groundwater temperature; selected samples were also incubated at other temperatures. Assays were performed at predetermined intervals over a 30-day period to determine the number of infective viruses remaining. Multiple regression analysis revealed that temperature was the only variable significantly correlated with the decay rates of all three viruses. No significant differences were found among the decay rates of the three viruses, an indication that MS-2 coliphage might be used as a model of animal virus survival in groundwater.

Abstract. Previous studies suggest that sorption of colloidal particles onto the air-water interface is an important mechanism for enhanced retention and retardation during transport in unsaturated systems. In this study, bacteriophages qbX174 and MS-2 and Brtracer were introduced into sand columns of various water contents as a step function under constant flow rates. The results showed that when a "reactive" (water washed) sand was used, the retention of both qbX174 and MS-2 increased significantly at low water saturation levels. However, when an "inert" (metals and metal oxides removed) sand was used, the effect of water content was minimal, although observable. These results suggest that in the presence of reactive solid surfaces, increased reactions at the solid-water interface rather than at the air-water interface dominates in virus removal and transport under unsaturated conditions. A model that incorporated reactions at both the solid-water and air-water interfaces was developed and successfully applied to the data.

No abstract

No abstract

As more and more cases of ground‐water contamination are reported, the public has become increasingly aware of the importance of preserving the quality of this limited resource, especially in areas totally dependent on ground‐water sources. Although most of the attention is focused on pollution by organic chemicals, these compounds are responsible for a relatively small percentage of ground‐water‐related disease outbreaks. The majority of waterborne disease outbreaks are caused by bacteria and viruses present in domestic sewage. Septic tanks contribute the largest volume of waste water, 800 billion gallons per year to the subsurface, and are the most frequently reported cause of ground‐water contamination associated with disease outbreaks. The U.S. Environmental Protection Agency has designated areas with septic tank densities of greater than 40 systems per mi2 (1 system per 16 acres) as regions of potential ground‐water contamination. Numerous cases of ground‐water contamination have been reported in areas of high septic tank density; lot sizes in these areas range from less than one‐quarter acre to three acres. The single most important means of limiting ground‐water contamination by septic tanks is to restrict the density of these systems in an area.