Sinks and Sources of Faecal Micro-Organisms in the Yarra River Estuary

(2009 – current)

This project aims to understand and reduce the public health risk of aquatic recreation in the Yarra River estuary.  The results of this project will be used to inform future management decisions for not only the Yarra River estuary, but other rivers and estuaries around the world facing similar contamination issues.

While recent investigations into locating and mitigating faecal pollutants delivered to the lower Yarra River were able to improve the quality of the system in the local vicinity of the identified faecal source through mitigation methods, there is some doubt about whether significant improvements will manifest in the entire Yarra River estuary.  It does not seem sufficient to mitigate faecal inputs into the estuary without a good understanding of all sources, sinks and processes which govern microbial concentrations in the estuary.  Armed with this knowledge, it will be possible to employ successful mitigation methods to reduce human health risks associated with users of this estuary.

However, in order to improve the usability of the estuary, we first need to understand the actual human health risks to users, meaning we must gain an understanding of the level of pathogens, and their viability, within the estuary.  Understanding the relationship between indicators and pathogens will inform future risk assessments and monitoring programs for the estuary. It will also inform managers of the effect of mitigation efforts on risks to users and how that relates to compliance targets (E. coli).

Considering the above statements, the following key objectives have been identified for this project:

  1. Understand the factors (sources, sinks and processes) which control the level of microorganisms (indicator bacteria and pathogens) in the Yarra River Estuary
  2. Understand the actual human health risks (and reductions after mitigation) of aquatic recreation in the Yarra River estuary.  Further, determine the interaction between faecal indicator bacteria and pathogens/risk and whether the key factors influencing faecal indicator bacteria in the Yarra River estuary are the same as for pathogens (i.e. should future monitoring regimes go to the trouble of collecting bacteria indicator data?).
  3. Based on the above understanding, identify appropriate mitigation  methods and locations for targeted trials

Project Partners:
Melbourne Water
ARC Linkage grant ($441k) – Sources, sinks and processes of faecal contamination in urban estuaries: a case study of the lower Yarra River estuary (Dr David McCarthy, Prof Ana Deletic, Dr Catherine Osborne and Prof Stanley Grant)


Research Team:
Dr David McCarthy, Prof Ana Deletic, Dr Catherine Osborne, Mr Peter Kolotelo and Ms Christelle Schang

McCarthy D.T., Bach P.M. and Deletic A. (2009) Conducting a microbial budget – a literature review. Monash University, Australia. PDF (0.8 MB)

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