Kinetics of Virus Inactivation by Ammonia

Abstract

Ammonia has been shown to be virucidal in sludge and NH 4 Cl solutions, although the rates at which viruses are inactivated have not been thoroughly studied. In the present studies, the kinetics of the poliovirus type 1 (strain CHAT) and bacteriophage f2 inactivation were examined in such a way that the effects of OH − and NH 4 + could be separated from those of NH 3 . Purified virus stocks were placed into solutions of NH 4 Cl and control solutions containing an equivalent concentration of NaCl and incubated at 20°C. The percentage of virus surviving was calculated, and the kinetics were evaluated by constructing semilogarithmic plots of data. At all pH values and NH 3 concentrations studied, the kinetics of the inactivation of both viruses were pseudo-first order. OH − had no measurable effect on the viruses, whereas the effects of NH 4 + and Na + were similar. A dose-response relationship between NH 3 and the viruses was also found. Bacteriophage f2 was approximately 4.5 times more resistant to the effects of NH 3 than was poliovirus.