Understanding the fate of Cryptosporidium and Giardia in storage reservoirs: a legacy of Sydney's water contamination incident

Abstract

Research Article| September 01 2000 Understanding the fate of Cryptosporidium and Giardia in storage reservoirs: a legacy of Sydney's water contamination incident Peter R. Hawkins; Peter R. Hawkins 1Australian Water Technologies, 51 Hermitage Rd, West Ryde, NSW 2114, Australia Tel: [phone] Fax: [phone]; E-mail: [e-mail] Search for other works by this author on: This Site PubMed Google Scholar Peter Swanson; Peter Swanson 2Australian Water Technologies, 51 Hermitage Rd, West Ryde, NSW 2114, Australia Search for other works by this author on: This Site PubMed Google Scholar Malcolm Warnecke; Malcolm Warnecke 2Australian Water Technologies, 51 Hermitage Rd, West Ryde, NSW 2114, Australia Search for other works by this author on: This Site PubMed Google Scholar Siva Raj Shanker; Siva Raj Shanker 2Australian Water Technologies, 51 Hermitage Rd, West Ryde, NSW 2114, Australia Search for other works by this author on: This Site PubMed Google Scholar Colin Nicholson Colin Nicholson 3Sydney Water Corporation, Bathurst Street, Sydney, NSW 2000, Australia Search for other works by this author on: This Site PubMed Google Scholar Journal of Water Supply: Research and Technology-Aqua (2000) 49 (6): 289–306. https://doi.org/10.2166/aqua.2000.0025 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Share Icon Share Twitter LinkedIn 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 Peter R. Hawkins, Peter Swanson, Malcolm Warnecke, Siva Raj Shanker, Colin Nicholson; Understanding the fate of Cryptosporidium and Giardia in storage reservoirs: a legacy of Sydney's water contamination incident. Journal of Water Supply: Research and Technology-Aqua 1 September 2000; 49 (6): 289–306. doi: https://doi.org/10.2166/aqua.2000.0025 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex High levels of Cryptosporidium oocysts and Giardia cysts (C&G) were detected in the raw and filtered water supply in Sydney, Australia, in July and August 1998. This paper describes the results of daily monitoring in the Sydney water supply catchments between December 1998 and May 1999, as one response to that incident.C&G were most abundant in the largest and most developed catchment. The levels of contamination in Sydney's raw water supply were of similar magnitude to raw waters in the USA and Europe, but the frequency of contamination was much lower.Physical variables of increased stream flow and turbidity were associated with the presence of C&G. The abundance of Giardia cysts was highly correlated with the number of Cryptosporidium oocysts. Other microbial indicators of faecal contamination (faecal coliforms and C. perfringens) were not useful indicators of either C or G.Both organisms occurred episodically in brief events, which spread rapidly through the water supply system, following stream rises in the catchment. Lake Burragorang was a poor barrier to the transfer of C&G into the bulk supply. C&G disappeared from Lake Burragorang within 4 weeks after each event. This loss rate was more rapid than predicted from settling theory. We observed settling rate of 5–10 m day−1, and postulate that sedimentation was accelerated by agglomeration of oo/cysts with other suspended particles.A design for monitoring programmes and management action in lakes to prevent C&G entering the supply to water treatment plants is suggested. catchments, Cryptosporidium, Giardia, management, reservoirs, oo/cyst sedimentation rates This content is only available as a PDF. © IWA Publishing 2000 You do not currently have access to this content.