Role of Temperature and Suwannee River Natural Organic Matter on Inactivation Kinetics of Rotavirus and Bacteriophage MS2 by Solar Irradiation

摘要

Although the sunlight-mediated inactivation of viruses has been recognized as an important process that controls surface water quality, the mechanisms of virus inactivation by sunlight are not yet clearly understood. We investigated the synergistic role of temperature and Suwannee River natural organic matter (SRNOM), an exogenous sensitizer, for sunlight-mediated inactivation of porcine rotavirus and MS2 bacteriophage. Upon irradiation by a fall spectrum of simulated sunlight in the absence of SRNOM and in the temperature range of 14-42 ℃, high inactivation rate constants, k_(obv), of MS2 (k_(obs)≦ 3.8h~(-1) or l-log_(10) over 0.6 h) and rottvirus (k_(obs) < 11.8 h~(-1) or ~1-log_(10) over 02 h) were measured. A weak temperature (14-42 ℃) dependence of K_(obs), values was observed for both viruses irradiated by the full sunlight spectrum. Under the same irradiation condition, the presence of SRNOM reduced the inactivation of both viruses due to attenuation of lower wavelengths of the simulated sunlight For rotavirus and MS2 solutions irradiated by only UVA and visible light in die absence of SRNOM, inactivation kinetics were slow (K_(obs) < 0.3 h~(-1) or 33 ℃, with low rotavirus K_(obs), values (k_(obs)≈ 0.2 h~(-1); 1-log_(10) unit reduction over 12 h) for the temperature range of 14-33 ℃ These K_(obs) values increased to 0.5 h~(-) at 43 ℃ and LSh~(-1) (l-log_(10) reduction over 1.6 h) at 50 ℃. While SRNOM-mediated exogenous inactivation of MS2 was triggered by singlet oxygen, the presence of hydrogen peroxide was important for rotavirus inactivation in the 40-50 ℃ range.