title: Into the deep: Evaluation of SourceTracker for assessment of faecal contamination of coastal waters.
abstract: 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.
authors.affiliation: Environmental and Public Health Microbiology Laboratory (EPHM Lab), Department of Civil Engineering, Monash University, Wellington Road, Clayton 3800, Victoria, Australia.
authors.forename: Rebekah
authors.initials: R
authors.lastname: Henry
authors.affiliation: Environmental and Public Health Microbiology Laboratory (EPHM Lab), Department of Civil Engineering, Monash University, Wellington Road, Clayton 3800, Victoria, Australia.
authors.forename: Christelle
authors.initials: C
authors.lastname: Schang
authors.affiliation: Micromon, Dept. of Microbiology, Monash University, Wellington Road, Clayton 3800, Victoria, Australia.
authors.forename: Scott
authors.initials: S
authors.lastname: Coutts
authors.affiliation: Environmental and Public Health Microbiology Laboratory (EPHM Lab), Department of Civil Engineering, Monash University, Wellington Road, Clayton 3800, Victoria, Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: Kolotelo
authors.affiliation: Melbourne Water, Latrobe St, Docklands 3008, Victoria, Australia.
authors.forename: Toby
authors.initials: T
authors.lastname: Prosser
authors.affiliation: Melbourne Water, Latrobe St, Docklands 3008, Victoria, Australia.
authors.forename: Nick
authors.initials: N
authors.lastname: Crosbie
authors.affiliation: Melbourne Water, Latrobe St, Docklands 3008, Victoria, Australia.
authors.forename: Trish
authors.initials: T
authors.lastname: Grant
authors.affiliation: Environment Protection Authority, 200 Victoria Street, Carlton 3053, Victoria, Australia.
authors.forename: Darren
authors.initials: D
authors.lastname: Cottam
authors.affiliation: Mornington Shire Council, 2 Queen Street, Mornington 3931, Victoria, Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: O'Brien
authors.affiliation: Environmental and Public Health Microbiology Laboratory (EPHM Lab), Department of Civil Engineering, Monash University, Wellington Road, Clayton 3800, Victoria, Australia.
authors.forename: Ana
authors.initials: A
authors.lastname: Deletic
authors.affiliation: Environmental and Public Health Microbiology Laboratory (EPHM Lab), Department of Civil Engineering, Monash University, Wellington Road, Clayton 3800, Victoria, Australia. Electronic address: david.mccarthy@monash.edu.
authors.forename: David
authors.initials: D
authors.lastname: McCarthy
mesh_terms: D001419:Bacteria / Q000145:classification / Q000235:genetics; D001493:Bathing Beaches; D061006:Bays / Q000382:microbiology; D019295:Computational Biology / Q000379:methods*; D004784:Environmental Monitoring / Q000379:methods; D063366:Estuaries; D005243:Feces / Q000382:microbiology*; D005843:Geography; D006801:Humans; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D011998:Recreation; D015203:Reproducibility of Results; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D045483:Rivers / Q000382:microbiology; D012722:Sewage / Q000382:microbiology; D012988:Soil Microbiology; D014739:Victoria; D014871:Water Microbiology
chemical_list: D012336:RNA, Ribosomal, 16S; D012722:Sewage
keywords: 16S rRNA amplicon; Bacterial communities; Coastal waters; Faecal contamination; Microbial source tracking; SourceTracker