Fig 1.
Site locations along the Yarra River, the Yarra Estuary, and Port Phillip Bay in Melbourne, Australia.
Site details provided in Table 1.
Table 1.
Site location and characteristics.
Table 2.
Analyses performed on samples.
Table 3.
Rain-gauge combinations used for rainfall analysis at each sampling site.
Fig 2.
E. coli concentration at the four upstream sites (left) and enterococci concentration recorded at the three beach sites (right).
The dashed and plain lines represents the SEPP thresholds for waters used for primary and secondary contact recreation in the Yarra River, respectively (E. coli = 150 MPN/100 mL and 1000 MPN/100 mL). For the marine water (right) the plain line represents the two thresholds mentioned in the SEPP for Water of Port Phillip Bay that are commonly used for long-term water quality assessment.
Table 4.
Summary statistics for E. coli and enterococci concentrations estimated using IDEXX Colilert and Enterolert, Median [5th; 95th]. n is the number of samples, with [>dl] being the number of samples greater than the detection limit indicated.
The water quality assessment category was estimated using NHMRC Guidelines for Managing Risks in Recreational Water Quality [22]. The % exceedance and the long-term water quality assessment were based on SEPP values [1, 2] for fresh and marine water.
Fig 3.
E. coli (at YER, WAR, DFS and MOR) and enterococci (at ELW, FRA, and RYE): concentrations vs time since last rainfall of >1 mm over 24 hours.
Fig 4.
Enterococci concentration measured in the EPHM laboratory vs concentration reported on the EPA Beach Report website.
Both results are from the IDEXX Enterolert method.
Fig 5.
Method comparison: overall and site-specific.
(a) E. coli TECTA™ vs IDEXX Colilert; (b) total coliform TECTA™ vs IDEXX Colilert; and (c) Enterococci TECTA™ vs IDEXX Enterolert. In each plot, the solid lines represent the 1:1 relationship.
Fig 6.
Method comparison: overall and site-specific, enterococci US EPA Method 1611 qPCR vs IDEXX Enterolert.
In each plot, solid lines represent the 1:1 relationship.
Fig 7.
Comparison between IDEXX enterococci concentration recorded at ELW, FRA, and RYE, and IDEXX E. coli concentrations observed at MOR, DFS, WAR, and YER vs proportion of total FIOs (a and b), Enterobacteriaceae family (c and d), Enterococcaceae family (e and f), and Enterococcus genus (g and h) as measured by the NGS method.
Table 5.
Costs and processing times of the different methods, based on 2014–2015 summer monitoring.
All values were estimated on the assumption that a batch of 15 samples are analysed. Consumable costs were estimated as a ratio in comparison to IDEXX consumables.