Inactivation of Hepatitis A Virus and Other Model Viruses by Free Chlorine and Monochloramine

The kinetics and extent of inactivation of two strains of Hepatitis A Virus (HAV HM175 and HAV MD1) as well as three other viruses, Coxsackievirus B5 (CB5) and Coliphage MS2 and ΦX174, by 0.5 mg/l free chlorine at pH 6.0, 8.0 and 10.0 and by 10 mg/l monochloramine, pH 8.0, at 5°C in 0.01M phosphate buffer were determined. Both strains of HAV were relatively sensitive 0.5 mg/l free chlorine but relatively resistant to 10 mg/l monochloramine. Compared to the HAV strains, CB5 was quite resistant to inactivation by free chlorine but similar in resistance to inactivation by monochloramine. The coliphages were, in general, more sensitive to inactivation by free chlorine than the enteric viruses at pH 6.0 and 8.0. ΦX174 was inactivated the most rapidly of all the viruses tested and showed a sensitivity to inactivation at pH 10.0 intermediate between that of HAV and CBS. MS2 was more sensitive to inactivation by free chlorine at pH 6.0 than the HAV strains, but at the higher pH's, was inactivated at similar or slightly slower rates than that of the HAV. ΦX174 was inactivated most rapidly of all viruses tested by 10 mg/1 monochloramine, pH 8,0, while MS2 was the most resistant to inactivation under these conditions. KEY WORDS: Hepatitis A Virus, Coxsackievirus, Enterovirus, Coliphages, Disinfection, Inactivation, Free Chlorine, Monochloramine, Water.Master of Science in Public Healt