2005/11 + 2016/18 – Castlemaine (Victoria) – E.coli, Nickel, Turbidity

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Castlemaine (Victoria) – E.coli
4/1/07: Castlemaine (Victoria) 2org/100mL. (sample at storage basin)
No known cause – possibly due to low chlorine residual or bird entry.  All possible entry points to the basin sealed. Sodium hypochlorite added to tank (5 mg/L). Re-sampling completed showing no further E.Coli.

2007/8 Castlemaine E.Coli. 1orgs/100ml 98.5% samples no e.coli (1 positive)

2010/11 Castlemaine E.coli  1/100mL (98.5% samples no e.coli ) (1 positive)

“E.coli

Thermotolerant coliforms are a sub-group of coliforms that are able to grow at 44.5 ± 0.2°C. E. coli is the most common thermotolerant coliform present in faeces and is regarded as the most specific indicator of recent faecal contamination because generally it is not capable of growth in the environment. In contrast, some other thermotolerant coliforms (including strains of Klebsiella, Citrobacter and Enterobacter) are able to grow in the environment and their presence is not necessarily related to faecal contamination. While tests for thermotolerant coliforms can be simpler than for E. coli, E. coli is considered a superior indicator for detecting faecal contamination…” ADWG

Castlemaine (Victoria) – Nickel

7 Nov 2016 – Castlemaine (Victoria) – Nickel 0.1mg/L

A sample, collected from the distribution system as part of Coliban Water’s sampling program, had an elevated nickel level of (0.1mg/L), exceeding the water quality standard of 0.02mg/L. The investigation undertaken has concluded that the nickel exceedance appears to be unexplainable anomaly. It was an isolated incident, and not an ongoing issue, and the probable
cause of the elevated nickel result was contamination during sampling procedures.
Detailed investigations were undertaken to identify the root cause of the elevated Nickel result, which included an assessment of raw water quality, treatment plant performance, and repeat sampling in the distribution network. The samples were analysed with different analytical methods and also by another accredited laboratory to ensure there were no ongoing issues.
Resamples were taken to establish that the issue was an isolated event, was not ongoing
and to ensure that the water being supplied to customers was safe. Stainless steel fittings used to collect the samples were replaced to eliminate doubt that nickel may be leaching from old stainless steel fittings. The investigation could not identify or determine the source of the elevated nickel.
https://www.coliban.com.au/site/root/operations/documents/ColibanWaterSDWAAnnualReport2016_2017.pdf

5/2/18: Castlemaine (Victoria) – Nickel 0.066mg/L

A sample, collected from the distribution system as part of Coliban Water’s sampling
program, had an elevated level of nickel (0.066 mg/L), exceeding the health-based guideline value for nickel (0.02mg/L) in the ADWG. The investigation undertaken has concluded that the nickel exceedance appears to be an unexplainable anomaly. It was an isolated incident and not an ongoing issue, and the probable cause of the elevated nickel result was contamination during sampling procedures.

Nickel: ADWG Health Guideline 0.02mg/L. A chemical element and silvery white corrosion resistant metal with a golden tinge. 60% of nickel production is used in nickel steel (particularly stainless steel). In water, mainly a problem with nickel plated fittings. Main releases to the environment are from the burning of fossil fuels and in waste discharges from electroplating industries.

2005/6 – Castlemaine (Victoria) – Turbidity

2005/6 – Castlemaine (Victoria) – Turbidity 7NTU (maximum detection)

Chlorine-resistant pathogen reduction: Where filtration alone is used as the water treatment
process to address identified risks from Cryptosporidium and Giardia, it is essential
that filtration is optimised and consequently the target for the turbidity of water leaving
individual filters should be less than 0.2 NTU, and should not exceed 0.5 NTU at any time
Disinfection: A turbidity of less than 1 NTU is desirable at the time of disinfection with
chlorine unless a higher value can be validated in a specific context.

Aesthetic: Based on aesthetic considerations, the turbidity should not exceed 5 NTU at the
consumer’s tap