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

Romero, Ofelia C.; Straub, Anthony P.; Kohn, Tamar; Nguyen, Thanh H.

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

Type

Article

Authors

Romero, Ofelia C.
Straub, Anthony P.
Kohn, Tamar
Nguyen, Thanh H.

Date

2011-12-15

Abstract

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 full spectrum of simulated sunlight in the absence of SRNOM and in the temperature range of 14-42 °C, high inactivation rate constants, kobs, of MS2 (k obs ≤ 3.8 h-1 or 1-log10 over 0.6 h) and rotavirus (kobs ≤ 11.8 h-1 or ∼1-log10 over 0.2 h) were measured. A weak temperature (14-42 °C) dependence of kobs 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 the absence of SRNOM, inactivation kinetics were slow (kobs < 0.3 h-1 or <1-log10 unit reduction over 7 h) and temperature-independent for the range considered. Conversely, under UVA and visible light irradiation and in the presence of SRNOM, temperature-dependent inactivation of MS2 was observed. For rotavirus, the SRNOM-mediated exogenous inactivation was only important at temperatures >33 °C, with low rotavirus kobs values (kobs ≈ 0.2 h-1; 1-log10 unit reduction over 12 h) for the temperature range of 14-33 °C. These kobs values increased to 0.5 h-1 at 43 °C and 1.5 h-1 (1-log10 reduction over 1.6 h) at 50 °C. 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 °C range. © 2011 American Chemical Society.

Citation

Romero OC, Straub AP, Kohn T, Nguyen TH (2011) Role of Temperature and Suwannee River Natural Organic Matter on Inactivation Kinetics of Rotavirus and Bacteriophage MS2 by Solar Irradiation. Environ Sci Technol 45: 10385–10393. Available: http://dx.doi.org/10.1021/es202067f.

Acknowledgements

We acknowledge the financial support of NSF CTS-0120978 and its supplements, USDA Grant No. 2008-35102-19143, and NSF CAREER grant to T.H.N. (0954501), and NSF GRF DGE 07-15088 FLW to O.C.R. This work is partially funded by the Academic Excellence Alliance (AEA) program at King Abdullah University of Science and Technology (KAUST).