Inactivation of poliovirus by gamma irradiation of wastewater sludges.

The effect of gamma radiation on poliovirus infectivity seeded in sludge samples was investigated in order to determine the radiation dose required to inactivate 90% of viral infectivity (D10). Sludges were obtained from anaerobic pretreated sewages produced by San Felipe, a wastewater treatment facility located at the Tucuman province, Argentina. A D10 of 3.34 kGy was determined for poliovirus type III, Sabin strain, suspended in sludge samples. This value dropped to 1.92 kGy when the virus was suspended in water. A virucidal effect associated to sludges was also demonstrated. These results will be of interest when considering the dose of gamma radiation to be applied to wastewater sludges in order to preserve the environment from viral contamination.