Effect of effluent quality and temperature on the persistence of viruses in soil

Abstract

Survival and adsorption of pathogenic viruses in soil material can effect the extent of groundwater pollution by the application of wastewater effluents to soil. This study was conducted to determine the effect of soil composition and wastewater quality on the adsorption of pathogenic viruses (hepatitis A virus and poliovirus 1) and model bacteriophages onto soil. Moreover, the effect of temperature, soil composition and water quality on the die-off of pathogenic viruses and model bacteriophages was also studied. The effect of water quality on virus adsorption to soil was virus type dependant. Poliovirus 1 adsorption was the highest regardless of water type, whereas the poorest adsorption was observed for MS2 bacteriophage. Intermediate adsorption rates were observed for PRD-1 bacteriophage. No die-off was observed for any one of the studied viruses (HAV, poliol, MS2 and PRD-1) after 20 days incubation in soil saturated with secondary/tertiary treated wastewater at 10°C. At 23°C, the greatest die-off was observed for MS2 bacteriophage, which was incubated in soil saturated with secondary and tertiary treated effluents. Intermediate die-off was observed for poliovirus 1, whereas negligible die-off was observed for HAV and PRD-1 bacteriophages. This indicates that pathogenic viruses can survive for long period of time in soil at ambient temperatures. Our results indicate that polio 1 and MS2 bacteriophage can not be used as models for the persistence of pathogenic viruses such as HAV in soil. PRD-1 bacteriophage has been found to be more suitable than MS2 to predict the persistence of pathogenic viruses especially at ambient temperatures.