EFFECT OF EFFLUENT QUALITY AND TEMPERATURE ON THE PERSISTENCE OF VIRUSES IN SOIL

Survival and adsorption of pathogenic viruses in soil material can eff ect the extent of groundwater pollution by the application of wastewat er effluents to soil. This study was conducted to determine the effect of soil composition and wastewater quality on the adsorption of patho genic viruses (hepatitis A virus and poliovirus 1) and model bacteriop hages onto soil. Moreover, the effect of temperature, soil composition and water quality on the die-off of pathogenic viruses and model bact eriophages was also studied. The effect of water quality on virus adso rption to soil was virus type dependant. Poliovirus 1 adsorption was t he highest regardless of water type, whereas the poorest adsorption wa s observed for MS2 bacteriophage. Intermediate adsorption rates were o bserved for PRD-1 bacteriophage. No die-off was observed for any one o f the studied viruses (HAV, polio1, MS2 and PRD-1) after 20 days incub ation in soil saturated with secondary/tertiary treated wastewater at 10 degrees C. At 23 degrees C, the greatest die-off was observed for M S2 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 i ndicate that polio 1 and MS2 bacteriophage can not be used as models f or the persistence of pathogenic viruses such as HAV in soil. PRD-1 ba cteriophage has been found to be more suitable than MS2 to predict the persistence of pathogenic viruses especially at ambient temperatures. Copyright (C) 1996 IAWQ.