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Efficacy of Inactivation of Human Enteroviruses by Multiple-Wavelength UV LEDs
Citation:
Ryu, H., S. Beck, L. Boczek, N. Brinkman, K. Linden, O. Lawal, AND S. Hayes. Efficacy of Inactivation of Human Enteroviruses by Multiple-Wavelength UV LEDs. Presented at American Society of Microbiology general meeting, Boston, MA, June 16 - 20, 2016.
Impact/Purpose:
Presenting the efficacy of inactivation of four human enteroviruses by multiple-wavelength UV LEDs in American Society for Microbiology general meeting.
Description:
Ultraviolet (UV) light has been successfully used for treating a broad suite of pathogens without the concomitant formation of carcinogenic disinfection by-products (DBPs). However, conventional mercury UV lamps have some practical limitations in water treatment applications, such as the inefficiency of energy consumption and more importantly potential mercury contamination upon disposal of the lamps. The recent invention of a novel light-emitting-diodes (LED) device generating germicidal UV wavelengths could eliminate the aforementioned limitations. In this study, we investigated the efficacy of multiple-wavelength UV LEDs for inactivating USEPA contaminant candidate list (CCL) RNA enteroviruses. Of 12 enterovirus species, serotype representatives of the four human enteric species (enterovirus A-D) such as coxsackievirus A10 (CVA10), echovirus 30 (Echo30), poliovirus 1 (PV1), and enterovirus 70 (EV70) respectively were selected as testing RNA viruses. Bench-scale performance evaluation was conducted using a collimated beam (CB) apparatus with LEDs emitting at 260 nm, 280 nm, and the combination of 260|280 nm together, as well as a monochromatic low-pressure (LP) UV lamp at 254 nm for comparison. The CB tests were performed with mixed stocks of four viruses. Infectious virus concentrations were determined using an integrated cell culture reverse transcriptase quantitative PCR (ICC-RTqPCR). The 260 nm LED was most effective at inactivating all enteroviruses tested, followed by the 260|280 nm LED, LP UV and lastly the 280 nm LED. These results are favorably comparable to our companion study with MS2 coliphage (RNA virus), suggesting no synergistic inactivation of RNA viruses by the 260|280 nm combination. Specifically, for a 2-log inactivation (i.e., 99% reduction) credit by the most effective 260 nm LED, UV doses averaged approximately 8 mJ/cm2 for CVA10 and PV1, 10 mJ/cm2 for EV70, and 13 mJ/cm2 for Echo30. These UV doses for the viruses tested yielded much greater inactivation rate constants than MS2 coliphage and the most UV resistant adenoviruses. Overall, UV LEDs showed the capability to effectively inactivate the CCL enteroviruses tested. Superior performance of the 260 nm LED to conventional LP UV encourages further studies on its applicability for sustainable water treatment and other CCL pathogens.
