2014 February + 2016/20: Cornwall (Tas). E.coli, High Lead & Mercury detections, Aluminium, Temperature


Cornwall/Miners Park (Tasmania) – E.coli

October 13 2015: Cornwall/Miners Park (Tasmania) – E.coli 1 MPN100/mL

February 23 2016: Cornwall/Miners Park (Tasmania) – E.coli 1 MPN100/mL

March 15 2016: Cornwall/Miners Park (Tasmania) – E.coli 14.6 MPN100/mL

June 21 2016: Cornwall/Miners Park (Tasmania) – E.coli 3.1 MPN100/mL

2016/17: Cornwall (Tasmania) – E.coli 1 exceedence

20/3/2018: Cornwall (Tasmania) – E.coli E. coli of 4.1 MPN/100mL in monthly compliance sample

June 2018: Cornwall – E.coli detections occurred during the period the system was subject to a BWA. A newly constructed WTP provides treated water, after a rigorous testing program in consultation with DoH. The BWA was removed 15 June 2018 and met the microbiological compliance target when Potable. 91.7% compliance

Escherichia coli should not be detected in any 100 mL sample of drinking water. If detected
in drinking water, immediate action should be taken including investigation of potential
sources of faecal contamination.

“Coliforms are Gram-negative, non-spore-forming, rod-shaped bacteria that are capable of aerobic and facultative anaerobic growth in the presence of bile salts or other surface active agents with similar growth-inhibiting properties. They are found in large numbers in the faeces of humans and other warm-blooded animals, but many species also occur in the environment.

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 2011

Cornwall – Tasmania – Lead

“The RTI information revealed that the highest levels of lead detected in Tasmania [averaged out over the year] were in the community of Cornwall in the states north east. The high levels were caused by a spike in lead, >8 times the ADWG in February 2014. [Another reading of 64.4μg/L was recorded by TasWater in May 2014, but not presented in the RTI data].”

13/11/2020: Cornwall (Tasmania)      Lead 73.7 ug/l

Australian Drinking Water Guideline for Lead is 10μg/L

Source: A Snapshot of Tasmanian Non-Microbiological Detections in Drinking Water July 2013-June 2014. Friends of the Earth Australia (October 2015)

Highest Tasmanian Mercury Reading 2009-11: Cornwall 0.0017mg/L Ben Lomond Water

Australian Drinking Water Guideline for Mercury is 1μg/L  (0.001mg/L)

Mercury, if it enters the ecosystem can transform into the more toxic methylmercury where it can bioaccumulate. Methylmercury is highly toxic to human embryos, fetuses, infants and children. Mercury has numerous sources including old gold mines, where mercury was used in gold recovery process. It has been estimated that 950 tonnes of mercury was deposited into Victorian soil, rivers and streams during the various gold rushes.

Cornwall (Tasmania) – Aluminium

June 8 2016: Cornwall (Tasmania) – Aluminium 0.582 mg/L

According to the ADWG, no health guideline has been adopted for Aluminium, but that the issue is still open to review. Aluminium can come from natural geological sources or from the use of aluminium salts as coagulants in water treatment plants. According to the ADWG “A well-operated water filtration plant (even using aluminium as a flocculant) can achieve aluminium concentrations in the finished water of less than 0.1 mg/L.

The most common form of aluminium in water treatment plants is Aluminium Sulfate (Alum). Alum can be supplied as a bulk liquid or in granular form. It is used at water treatment plants as a coagulant to remove turbidity, microorganisms, organic matter and inorganic chemicals. If water is particularly dirty an Alum dose of as high as 500mg/L could occur. There is also concern that other metals may also exist in refined alum.

While the ADWG mentions that there is considerable evidence that Aluminium is neurotoxic and can pass the gut barrier to accumulate in the blood, leading to a condition called encephalopathy (dialysis dementia) and that Aluminium has been associated with Parkinsonism dementia and amyotrophic lateral sclerosis, the NHMRC, whilst also acknowledging studies which have linked Aluminium with Alzheimer disease, has not granted Aluminium a NOEL (No Observable Effect Level) due to insufficient and contradictory data. Without a NOEL, a health guideline cannot be established. The NHMRC has also stated that if new information comes to hand, a health guideline may be established in the future.

In communication with Aluminium expert Dr Chris Exley (Professor in Bioinorganic Chemistry
The Birchall Centre, Lennard-Jones Laboratories, Keele University, Staffordshire UK) in March 2013 regarding high levels of Aluminium detected in the South Western Victorian town of Hamilton
“It is my opinion that any value above 0.5 mg/L is totally unacceptable and a potential health risk. Where such values are maintained over days, weeks or even months, as indeed is indicated by the data you sent to me, these represent a significant health risk to all consumers. While consumers may not experience any short term health effects the result of longer term exposure to elevated levels of aluminium in potable waters may be a significant increase in the body burden of aluminium in these individuals. This artificially increased body burden will not return to ‘normal’ levels when the Al content of the potable water returns to normal but will act as a new platform level from which the Al body burden will continue to increase with age.

Ross – Tasmania – Temperature

February 23 2016: Cornwall (Tasmania) – Temperature 20.1C


“No guideline is set due to the impracticality of controlling water temperature.
Drinking water temperatures above 20°C may result in an increase in the number of

Temperature is primarily an aesthetic criterion for drinking water. Generally, cool water is more palatable than warm or cold water. In general, consumers will react to a change in water temperature. Complaints are most frequent when the temperature suddenly increases.

The turbidity and colour of filtered water may be indirectly affected by temperature, as low water temperatures tend to decrease the efficiency of water treatment processes by, for instance, affecting floc formation rates and sedimentation efficiency.

Chemical reaction rates increase with temperature, and this can lead to greater corrosion of pipes and fittings in closed systems. Scale formation in hard waters will also be greater at higher temperatures…

Water temperatures in major Australian reticulated supplies range from 10°C to 30°C. In some long, above-ground pipelines, water temperatures up to 45°C may be experienced…

The effectiveness of chlorine as a disinfectant is influenced by the temperature of the water being dosed. Generally higher temperatures result in more effective disinfection at a particular chlorine dose, but this may be counterbalanced by a more rapid loss of chlorine to the atmosphere (AWWA 1990).

Cornwall – Tasmania – Turbidity

March 15 2016: Cornwall (Tasmania) – Turbidity 6.92 NTU

2016/17: Cornwall Turbidity – 5.1 NTU (max), 1.48 NTU (mean)

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.