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Selected Publication:

Publication type: Journal Article
Document type: Full Paper

Year: 2005

Author(s): Mamane-Gravetz, H; Linden, KG; Cabaj, A; Sommer, R

Title: Spectral sensitivity of Bacillus subtilis spores and MS2 coliphage for validation testing of ultraviolet reactors for water disinfection.

Source: Environ Sci Technol. 2005; 39(20):7845-7852

Authors Vetmeduni Vienna:

Cabaj Alexander

Vetmed Research Units
Institute of Physiology, Pathohysiology and Biophysics, Unit of Physiology and Biophysics

Project(s): UV-Disinfection of water

The microbicidal UV fluence under polychromatic radiation from UV lamps is typically measured using the DNA absorbance spectrum as a weighting factor for the relative wavelength effectiveness. However, this DNA-based weighting does not necessarily match the spectral sensitivity of the microorganism being tested. Bacillus subtilis spores are often used for UV reactor validation in Europe, while MS2 coliphage is typically used for validation testing in the United States. These organisms were exposed to quasi-monochromatic UV irradiation across the microbicidal spectrum at wavelengths of 214, 230, 240, 254, 265, 280, and 293 nm. MS2 was three times more sensitive to wavelengths near 214 nm compared to the 254 nm output of low-pressure lamps, while B. subtilis spores were most sensitive to wavelengths around 265 nm. Use of these action spectra, compared to the DNA-based weighting, resulted in differences in the calculated polychromatic UV fluence. Consequently, the action spectrum, which is specific for each microorganism, has implications on the uncertainty of UV fluence determination during validation of reactors with polychromatic UV lamps.

Keywords Pubmed: Bacillus subtilis*
Levivirus/radiation effects*
Reproducibility of Results
Spores, Bacterial/radiation effects*
Ultraviolet Rays*
Water Purification/methods*

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