Aerial dispersal and survival of sewage-derived faecal coliforms in Antarctica

This study demonstrates for the first time that faecalcoliform bacteria can survive airborne transfer in Antarctica, but are unlikely to survive for prolonged periods following deposition due to environmental stresses. The dispersal and survival of airborne faecalcoliform bacteria from the sewage outfall at Rothera Research Station (Adelaide Island, Antarctic Peninsula) was examined. Northerly winds created the potential for sewage aerosols to be blown the 150 m from the outfall to the research station. During moderate wind velocities (∼15 m s−1), faecalcoliform bacteria were detected up to 175 m downwind of the outfall amongst the station buildings. However, moderate doses of solar UV radiation (∼20 W m−2) were capable of reduced the number of viable wind-deposited bacteria by up to 99.9%, compared with periods of low solar UV radiation (∼1 W m−2). Further experiments showed that, within 1 h of deposition, desiccation stress and solar radiation independently reduced coliform viability by up to 99.8% and 99.98%, respectively. These results imply that airborne faecalcoliforms are unlikely to survive for prolonged periods following deposition or cause infection of local wildlife or human populations, though this may not be the case for more stress-resistant microorganisms.

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