Because of the increasing emphasis placed upon land application as a means of wastewater disposal, it is important to evaluate the influences of different factors upon virus survival in soil. The objective of this study was to measure the effects of various environmental variables on virus persistence. Test samples of soil were placed in vials, and the soil was wetted with suspensions of virus in either distilled water, unchlorinated secondary sewage effluent, or mixtures of effluent and water. The viruses used were coxsackieviruses A9 and B3, echovirus 1, poliovirus 1, rotavirus SAll, and bacteriophages T2 and MS2. The rate of virus inactivation was evaluated statistically with regard to conditions under which the vials were incubated and to the soil characteristics. The factors that were found to influence virus survival were temperature, soil moisture content, presence of aerobic microorganisms, degree of virus adsorption to the soil, soil levels of resin-extractable phosphorus, exchangeable aluminum, and soil pH. Overall, temperature and virus adsorption to soil appeared to be the most important factors affecting virus survival. Viruses conta;ined in wastewater that is applied to soil can persist in the environment for prolonged periods of time. Indigenous enteroviruses have been isolated from soils of rapid infiltration basins receiving primary and secondary sewage effluents (7). Indigenous enterovi

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The rates of inactivation of poliovirus 1, echovirus 7, coxsackievirus B3, and simian rotavirus SAil were compared in polluted and nonpolluted fresh and estuarine water samples. The study was done in two parts, comparing virus survival in samples taken 1 year apart from the same sites. The survival studies were perforned at 200C and at the natural pH of the water samples. In the first part of the study, the time required for a 3-logio reduction in the initial virus titers was 2 to 3 days in the estuarine water samples and varied from 3 to >14 days in the freshwater samples. In the second part of the study, no clear distinction was found between survival of viruses in freshwater samples and survival in estuarine water samples. The time required for a 3-logio reduction in the initial virus titers in the second part of the study varied from 12 to >14 days. This indicates that there is a nonseasonal change in factors in the water which affect virus survival. In this study SA11 survival time (used as a model for human virus) was well within the range exhibited by the enteroviruses, indicating that it also is environmentally stable in natural waters.

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