|Thurston Enriquez, Jeanette|
Submitted to: Applied and Environmental Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/1/2007
Publication Date: 12/1/2007
Citation: Linden, K.G., Thurston Enriquez, J.A., Schaefer, R., Malley, J.P. 2007. Enhanced inactivation of adenovirus under polychromatic UV lamps. Applied and Environmental Microbiology. 73:7571-7574. Interpretive Summary: Adenovirus is recognized as the most UV-resistant waterborne pathogen of concern to public health microbiologists. This is due to recent evidence that adenoviruses are extremely resistant to low pressure UV light systems. These systems are used for water treatment (disinfection of pathogenic microorganisms). Other UV light technologies are also available for water treatment but information on their effectiveness to inactivate adenovirus is lacking. This study determined the inactivation of adenoviruses by polychromatic UV sources: medium pressure and pulsed UV light technologies. The polychromatic UV technologies, assessed for their ability to inactivate adenoviruses, were more effective than low pressure UV systems for inactivating adenoviruses in water. This work has important implications regarding effective water treatment, public health and the future of UV light regulations for virus disinfection.
Technical Abstract: Adenovirus is recognized as the most UV-resistant waterborne pathogen of concern to public health microbiologists. The US EPA has stipulated that a UV fluence (dose) of 186 mJ cm-2 is required for 4-log inactivation credit in water treatment. However, all adenovirus inactivation data to date published in the peer-reviewed literature has performed UV disinfection experiments using UV irradiation at 253.7 nm produced from a conventional low pressure UV source. Work reported here presents inactivation data for adenovirus utilizing polychromatic UV sources and details the significant enhancement in inactivation using these polychromatic sources. Using full spectrum medium pressure UV lamps, 4-log inactivation of adenovirus type 40 is achieved at a UV fluence of less than 60 mJ cm-2 and a surface discharge pulsed UV sources required a UV fluence of less than 40 mJ cm-2. The action spectrum for adenovirus type 2 was also developed and partially explains the improved inactivation based on enhancements at wavelengths below 230 nm. Implications for water treatment, public health, and the future of UV regulations for virus disinfection are discussed.