Responses of Salmonella typhimurium LT2, Vibrio harveyi, and Cryptosporidium parvum to UVB and UVA radiation

Publication date: 1 September 2019Source: Chemical Engineering Journal, Volume 371Author(s): Margaret M. Busse, Matouš Becker, Bruce M. Applegate, Joseph W. Camp, Ernest R. BlatchleyAbstractConventional solar disinfection (SODIS) processes rely on UVA radiation due to exclusion of shorter wavelengths by common SODIS containers. Because of this, these processes are slow and could be improved by inclusion of UVB radiation, which has been reported to be more effective for microbial inactivation than UVA on a photon basis, but is typically present at lower spectral irradiance. To examine the potential for microbial inactivation resulting from exposure to solar UVB radiation at sea-level, experiments were conducted to define the UVB/UVA action and effectiveness spectra for Salmonella typhimurium LT2, Vibrio harveyi, and Cryptosporidium parvum, which are representative of three of the most prevalent waterborne pathogens globally. For each organism, the action spectrum was similar in shape to its corresponding DNA absorption spectrum, thereby suggesting that inactivation of these organisms by UVB irradiation was largely attributable to DNA damage. Modeling and measurements of ambient solar UVB spectral irradiance were compared, indicating a trend of model over-prediction of spectral irradiance by up to 20% on cloudless days. Effectiveness spectra for organism/location pairs were calculated as the product of the action spectra and calculated spectral irradiance to identify the most ...
Source: Chemical Engineering Journal - Category: Chemistry Source Type: research