Into the deep: Evaluation of SourceTracker for assessment of faecal contamination of coastal waters

Rebekah Henry, Christelle Schang, Scott Coutts, Peter Kolotelo, Toby Prosser, Nick Crosbie, Trish Grant, Darren Cottam, Peter O'Brien, Ana Deletic, David McCarthy

Research output: Contribution to journalArticleResearchpeer-review

97 Citations (Scopus)


Faecal contamination of recreational waters is an increasing global health concern. Tracing the source of the contaminant is a vital step towards mitigation and disease prevention. Total 16S rRNA amplicon data for a specific environment (faeces, water, soil) and computational tools such as the Markov-Chain Monte Carlo based SourceTracker can be applied to microbial source tracking (MST) and attribution studies. The current study applied artificial and in-laboratory derived bacterial communities to define the potential and limitations associated with the use of SourceTracker, prior to its application for faecal source tracking at three recreational beaches near Port Phillip Bay (Victoria, Australia). The results demonstrated that at minimum multiple model runs of the SourceTracker modelling tool (i.e. technical replicates) were required to identify potential false positive predictions. The calculation of relative standard deviations (RSDs) for each attributed source improved overall predictive confidence in the results. In general, default parameter settings provided high sensitivity, specificity, accuracy and precision. Application of SourceTracker to recreational beach samples identified treated effluent as major source of human-derived faecal contamination, present in 69% of samples. Site-specific sources, such as raw sewage, stormwater and bacterial populations associated with the Yarra River estuary were also identified. Rainfall and associated sand resuspension at each location correlated with observed human faecal indicators. The results of the optimised SourceTracker analysis suggests that local sources of contamination have the greatest effect on recreational coastal water quality.

Original languageEnglish
Pages (from-to)242-253
Number of pages12
JournalWater Research
Publication statusPublished - 15 Apr 2016


  • Microbial source tracking
  • Coastal waters
  • Bacterial communities
  • 16S rRNA amplicon
  • SourceTracker
  • Faecal contamination

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