Deterministic model of microbial sources, fate and transport: a quantitative tool for pathogen catchment budgeting Presented by Christobel Ferguson Submitted in total fulfillment of the requirements of the degree of Doctor of Philosophy Department of Biotechnology and Biomolecular Science Faculty of Science The University of New South Wales June 2005 The object of the bacteriological examination of any water-supply is to ascertain whether that particular water is, or is not, one the consumption of which may give rise to disease or be prejudicial to its users, either at the time of examination or subsequently. Hygienists are unanimous in recognising that sewage and the excreta of human beings, diseased or healthy, must be looked upon as potential vehicles for disease production. The presence of the excreta of animals must also be looked upon as prejudicial, since it may contain harmful bacteria and other parasites. It is clear, therefore, that the detection of the presence of sewage and of human excreta, and to a lesser extent of animal excreta, must be the aim of the water bacteriologist. William G. Savage, B.Sc. M.D. from The Bacteriological Examination of Water-Supplies. London 1906. i ABSTRACT The most important priority for the management of Australian drinking water catchments is the control of pathogen loads delivered to raw water reservoirs and treatment plant intakes. A process-based mathematical model was developed to estimate pathogen catchment budgets (PCB) for Cryptosporidium, Giardia and E. coli loads generated within and exported from catchments. The model quantified key processes affecting the generation and transport of microorganisms from humans and animal excreta using land use and hydrologic data, and catchment specific information including point sources such as sewage treatment plants and on-site systems. The PCB model was applied in the Wingecarribee catchment, Sydney and used to predict and rank pathogen and indicator loads in dry weather, intermediate (<30 mm in 24 h) and large wet weather events (100mm in 24 h). Sensitivity analysis identified that pathogen excretion rates from animals and humans, and manure mobilisation rates were the most significant factors determining the output of the model. Comparison with water quality data indicated that predicted dry weather loads were generally within 1-2 log10 of the measured loads for Cryptosporidium and E. coli and within 1 log10 for Giardia. The model was subsequently used to predict and rank pathogen and indicator loads for the entire (16 000 km2) Sydney drinking water catchment. iii ORIGINALITY STATEMENT ‘I hereby declare that this submission is my own work and to the best of my knowledge it contains no materials previously published or written by another person, or substantial proportions of material which have been accepted for the award of any other degree or diploma at UNSW or any other educational institution, except where due acknowledgement is made in the thesis. Any contribution made to the research by others, with whom I have worked at UNSW or elsewhere, is explicitly acknowledged in the thesis. I also declare that the intellectual content of this thesis is the product of my own work, except to the extent that assistance from others in the project’s design and conception or in style, presentation and linguistic expression is acknowledged.’ Signed …………………………………………………. iv ACKNOWLEDGMENTS I would like to thank my supervisors for their support and guidance; Professor Brett Neilan (Biotechnology and Biomolecular Science, University of New South Wales), Professor Nicholas Ashbolt (Civil and Environmental Engineering, University of New South Wales), Dr. Daniel Deere (Water Futures Pty Ltd and CRC for Water Quality and Treatment) and Dr. Barry Croke (Integrated Catchment Assessment and Management Centre, Australian National University). I particularly thank Barry for coding the model in ICMS and FORTRAN and helping me to test the model by sensitivity analysis. I would like to thank the Cooperative Research Centre for Water Quality and Treatment, American Water Works Association Research Foundation, Water Services Association of Australia, Melbourne Water and the Sydney Catchment Authority. I would also like to thank the following people for their generous assistance. Martin Krogh, Chris Chafer, Bala Vigneswaran, Peter Paterson, Danielle Camenzulli, Julian Long, Stuart Naylor, Bruce Whitehill, Gary Bownds, Penny Knights, Tony Paull and Ben Shallis, Sydney Catchment Authority. Katrina Charles, Christine Kaucner, Dr Cheryl Davies, Nanda Altavilla, Dr Peter White, Paul Gwynne, Andrew Feitz, Paul Beavis, Dr David Roser, Robby Smith and Lynnette Menzies, University of New South Wales. Dr Peter Cox, Malcolm Warnecke, Dr Mark Angles, Merran Griffith, Richard Teffer, Myly Truong, Monica Logan, Mike Mannile, Hamish Manzi, Terry Adams and Lyn Tamsitt, Sydney Water Corporation. Professor Tony Jakeman and the research group at the Integrated Catchment Assessment and Management Centre, Australian National University. Dr. Ana Maria de Roda Husman, Dr. Jack Schijven and Dr Peter Teunis, National Institute of Public Health and the Environment (RIVM), the Netherlands. Dr. Melita Stevens, Melbourne Water. Professor Bill Cooper, University of North Carolina, USA. v Joerg Rodehutskors, University of Lippe and Hoexter, Germany. Stephen Burgun and Professor Richard Whittington, Sydney University. Peter Jackson and Dr. Paul Hackney, University of Western Sydney. Dr. Gertjan Medema and Dr. Wim Heijnen, KIWA Water Research, the Netherlands. Dr. Dennis Mulcahy, Dr. Dennis Steffensen, Rachael Miller and Professor Don Bursill, Cooperative Research Centre for Water Quality and Treatment. Professor Bob Wasson, Centre for Resource and Environmental Studies, Australian National University. Dr. Therese Flapper and Grant Leslie, Ecowise Environmental. Dr. Annette Davison, Water Futures. Special thank you to Elena Cotto for formatting the manuscript. Finally, I would like to thank my parents for their unqualified support of my academic pursuits, and my husband, Dr. Peter Beatson, for his encouragement and for the numerous discussions regarding various aspects of this work, without which, it might not have been completed. vi PUBLICATIONS Ferguson, C.M., Altavilla, N., Ashbolt, N.J. & Deere, D.A. (2003a) Prioritising Watershed Pathogen Research. Journal of American Water Works Association, 95(2), 92-102. Ferguson, C.M., Ashbolt, N.J. & Deere, D.A. (2004) Prioritisation of catchment management in the Sydney catchment - construction of a pathogen budget. Water Science and Technology: Water Supply, 4(2), 35-38. Ferguson, C.M., Croke, B.F.W., Beatson, P.J., Ashbolt, N.J. & Deere, D.A. (submitted- a) Development of a process-based model to predict pathogen budgets for the Sydney drinking water catchment. Journal of Water and Health. Ferguson, C.M., Davies, C.M., Kaucner, C., Krogh, M., Rodehutskors, J., Deere, D.A. & Ashbolt, N.J. (in press) Field scale transport of Cryptosporidium parvum, E. coli and PRD1 bacteriophage in surface runoff from bovine faecal pats under simulated rainfall. Journal of Water and Health. Ferguson, C.M., de Roda Husman, A.M., Altavilla, N., Deere, D. & Ashbolt, N.J. (2003b) Fate and transport of surface water pathogens in watersheds. Critical Reviews in Environmental Science and Technology, 33(3), 299-361. Ferguson, C.M., Kaucner, C., Krogh, M., Deere, D. & Warnecke, M. (2004) Comparison of methods for the concentration of Cryptosporidium oocysts and Giardia cysts from raw waters. Canadian Journal of Microbiology, 50, 675-82. Chalmers, R., Ferguson, C.M., Caccio, S., Gasser, R., Abs EL-Osta, Y., Heijnen, L., Xiao, L., Elwin, K., Hadfield, S., Sinclair, M. & Stevens, M. (2005) Direct comparison of selected methods for genetic categorisation of Cryptosporidium parvum and vii Cryptosporidium hominis species. International Journal for Parasitology, 35(4), 397- 410. Charles, K.J., Ashbolt, N.J., Ferguson, C., Roser, D.J., McGuinness, R. & Deere, D.A. (2003c) Impacts of centralised versus decentralised sewage systems on water quality in Sydney's drinking water catchments. Water Science & Technology, 48(11-12), 53-60. Cox, P., Griffith, M., Angles, M., Deere, D.A. & Ferguson, C.M. (2005) Concentrations of pathogens and indicators in animal feces in the Sydney watershed. Applied and Environmental Microbiology, 71(10), 5929-5934. Davies, C., Kaucner, C., Altavilla, N., Ashbolt, N., Hijnen, W., Medema, G., Deere, D., Krogh, M. & Ferguson, C. (2004a) Pathogen fate and transport in surface water flow. Water (Australia), 31(3), 57-62. Davies, C.M., Altavilla, N., Krogh, M., Ferguson, C.M., Deere, D.A. & Ashbolt, N.J. (2005a) Environmental inactivation of Cryptosporidium oocysts in catchment soils. Journal of Applied Microbiology, 98(2), 308-17. Davies, C.M., Logan, M.R., Rothwell, V.L., Krogh, M., Ferguson, C.M., Charles, K., Deere, D.A. & Ashbolt, N.J. (in press) Soil inactivation of viruses in septic seepage. Letters in Applied Microbiology. Miller, K., Ferguson, C.M., Gillings, M.R., Mitchell, H., Pappayut, S., Angles, M., Cox, P., Brusentiev, S. & Neilan, B. (submitted) Comparison of tracing and tracking tools for identifying bacterial contamination in drinking water catchments. Environmental Science and Technology. viii EXECUTIVE SUMMARY The World Health Organisation (WHO) has identified that pathogen contamination continues to be the greatest risk to the quality of drinking water supplies. Many water utilities are thus embracing the concept of risk management and the