2007/11 + 2016/19 – Bellbridge (Victoria) – E.coli, Trichloroacetic Acid, Iron, Turbidity

Bellbridge – Victoria – E.coli
20 December 2017. Bellbridge. E. coli detection (3 orgs/100 mL)
An E. coli detection (3 orgs/100 mL) occurred as part of routine monitoring in the reticulation at Bellbridge on 20 December 2017. The same sample had a chlorine residual of 0.56 mg/L, turbidity of < 0.1 NTU, pH of 6.6 and 3 coliforms/100 mL. The entry point to the reticulation was tested by the external laboratory on the same day and had no E. coli, a chlorine residual of 1.21 mg/L, turbidity of < 0.1 NTU, pH of 6.5 and no coliforms. There had been no operational
issues at the water treatment plant or main breaks that could impact water quality.
An Operator attended the site on the day of notification to investigate further. There was nothing visible at the detection site or at the tanks that could have contributed to the E. coli
result. Precautionary flushing was conducted. North East Water conducted a full investigation and determined that the result was not representative of the water supplied to this locality. DHHS agreed with the investigation report findings.

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

2010/11 – Bellbridge (Victoria) – Trichloroacetic Acid

2010/11: Bellbridge Trichloroacetic Acid 0.092mg/L

Australian Guidelines Trichloroacetic Acid 0.100mg/L

“Chloroacetic acids are produced in drinking water as by-products of the reaction between chlorine and naturally occurring humic and fulvic acids. Concentrations reported overseas range up to 0.16mg/L and are typically about half the chloroform concentration. The chloroacetic acids are used commercially as reagents or intermediates in the preparation of a wide variety of chemicals. Monochloroacetic acid can be used as a pre-emergent herbicide, dichloroacetic acid as an ingredient in some pharmaceutical products, and trichloroacetic acid as a herbicide, soil sterilant and antiseptic.” Australian Drinking Water Guidelines – National Health and Medical Research Council…

There are no epidemiological studies of TCA carcinogenicity in humans. Most of the human health data for chlorinated acetic acids concern components of complex mixtures of water disinfectant by-products. These complex mixtures of disinfectant by-products have been associated with increased potential for bladder, rectal, and colon cancer in humans [reviewed by Boorman et al. (1999); Mills et al. (1998)].” Ref: tmp/Trichloroacetic acid (TCA) CASRN 76-03-9 IRIS US EPA.htm

Bellbridge –  Victoria – Iron

2007/08: Bellbridge (Victoria)  – Iron 0.79mg/L (Highest level only)

2016/17:  Bellbridge Iron  0.32mg/L

Based on aesthetic considerations (precipitation of iron from solution and taste),
the concentration of iron in drinking water should not exceed 0.3 mg/L.
No health-based guideline value has been set for iron.

Iron has a taste threshold of about 0.3 mg/L in water, and becomes objectionable above 3 mg/L. High iron concentrations give water an undesirable rust-brown appearance and can cause staining of laundry and plumbing fittings, fouling of ion-exchange softeners, and blockages in irrigation systems. Growths of iron bacteria, which concentrate iron, may cause taste and odour problems and lead to pipe restrictions, blockages and corrosion. ADWG 2011

2017/18 – Bellridge (Victoria) – Turbidity

2017/18 – Bellridge (Victoria) – Turbidity 7.5NTU (max)

2018/19 – Bellridge (Victoria) – Turbidity 7.4NTU (max), 2.4NTU (av)

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