Microbial risk implications of rainfall-induced runoff events entering a reservoir used as a drinking-water source

Research Article| December 01 2007 Microbial risk implications of rainfall-induced runoff events entering a reservoir used as a drinking-water source R. S. Signor; R. S. Signor 1School of Civil and Environmental Engineering/Centre for Water and Waste Technology, The University of New South Wales, Sydney, NSW 2052, Australia Tel: +61(2) 9385 7896 Fax: +61(2) 9313 8624; E-mail: ryan.signor@student.unsw.edu.au Search for other works by this author on: This Site PubMed Google Scholar N. J. Ashbolt; N. J. Ashbolt 1School of Civil and Environmental Engineering/Centre for Water and Waste Technology, The University of New South Wales, Sydney, NSW 2052, Australia Search for other works by this author on: This Site PubMed Google Scholar D. J. Roser D. J. Roser 1School of Civil and Environmental Engineering/Centre for Water and Waste Technology, The University of New South Wales, Sydney, NSW 2052, Australia Search for other works by this author on: This Site PubMed Google Scholar Journal of Water Supply: Research and Technology-Aqua (2007) 56 (8): 515–531. https://doi.org/10.2166/aqua.2007.107 Article history Received: February 01 2006 Accepted: July 27 2007 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Share Icon Share Facebook Twitter LinkedIn Email Tools Icon Tools Cite Icon Cite Permissions Search Site Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll JournalsThis Journal Search Advanced Search Citation R. S. Signor, N. J. Ashbolt, D. J. Roser; Microbial risk implications of rainfall-induced runoff events entering a reservoir used as a drinking-water source. Journal of Water Supply: Research and Technology-Aqua 1 December 2007; 56 (8): 515–531. doi: https://doi.org/10.2166/aqua.2007.107 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Waterborne disease outbreaks have been associated with periods of heightened source water pathogen concentrations in treated drinking-water supplies. For their management it is necessary to identify and quantify the impacts of events which lead to adverse concentration fluctuations. The aim of this work was to estimate relative microbial risks to water consumers arising from one such event: rainfall-induced runoff entering a surface drinking-water reservoir in an Australian agricultural catchment. Runoff events are known to influence both the source water entering a reservoir and the ability of a reservoir to act as a barrier to pathogen progression. Hydrograph separation methods were used to distinguish ‘runoff event’ from baseflow periods and pathogen concentrations of the inflow to the reservoir during runoff and baseflow periods respectively were estimated. Relative impacts of runoff event periods on health risks to consumers were assessed using Quantitative Microbial Risk Assessment principles. Runoff event conditions predominated 14 % of the time. The proportions of infections attributable to runoff event periods from Cryptosporidium, Giardia and Campylobacter spp. were 57 %, 80 %, and 28 % respectively. Daily infection risks were greatest in winter months than other seasons primarily due to the higher frequency of runoff events. Results from this and similar analyses, aiming to assess impacts of explicitly identified events on consumer health risks, provides important information for water system risk management, e.g. identifying periods of heightened risk and setting management priorities. Campylobacter, Cryptosporidium, Giardia, microbial risk assessment, runoff events This content is only available as a PDF.