The first phase of the study was designed to determine the adsorption rate of viruses and microspheres to sandy and loamy soils and determine the adsorption efficiency of various viruses to soil. The adsorption of viruses to sandy and loamy soils has been found virus type dependent. The poorest adsorption was observed for MS2 bacteriophage while the greatest adsorption was observed for PRD-1. Adsorption sites on the soil material were not found as limiting factors for adsorption of viruses on soil material. The effect of water quality on adsorption has been found as virus type dependent.
The adsorption process of microspheres to soil material has been found to be similar to that of viruses and occurs within a very short period of time. Carboxylated (negatively charged) microspheres seems to adsorb more efficiently than plain microspheres to soil material.
At low temperatures (10oC), and under saturated conditions no virus die-off was observed, therefore under these conditions virus can survive for long period of time. At 23oC, and saturated conditions, the greatest die-off was observed for MS2 bacteriophage, whereas, negligible die-off was for PRD-1 bacteriophage and hepatitis A virus. Considering the survival results MS2 bacteriophages is not suitable as indicator for pathogenic viruses persistence in soil material. Furthermore, temperature, is more important than any other factor for the inactivation of viruses.