DHS directed North East Water, under section 34 of the Safe Drinking water Act, to institute a
Boil Water Notice, effective, August 2007.
As part of North East Water‟s ongoing risk management program for the Myrtleford supply an
extensive microbiological testing program, including E.coli and specific pathogen testing, was
implemented. This involved weekly testing over 4 different reticulation sites. During this
program E.coli was detected in January, February and April.
When the data was recalculated in line with the DHS-SDWA sampling regime of one
reticulation site per week, Myrtleford was deemed to be compliant with the E.coli water quality
standard.
Upon reviewing the data, and risk profile for the supply, DHS advised NEW to implement a
Seasonal Boil Water Notice, which resulted in the lifting of the Boil Water Notice on May 1
2008. If any E.coli were detected between the May 2008 and November 2008 period there
would be further discussions to determine the Boil Water Notice status.
An upgrade is planned for this system to implement multiple barriers and provide drinking
water compliant with the regulations.
Water Notice was in place. Retest was clear.
was clear. Boil Water Notice was in place.
Media release had been made late January to remind residents to continue to boil their water.
Retest was clear.
24/08/09 Myrtleford E. coli detection at Entry point to Myrtleford reticulation 1 org/100mL Ultra violet lamps were checked and working. A resample was clear.
7/09/09 Myrtleford E. coli 1 org/100mL reticulation No filtration, no residual disinfection. Resample was clear.
2/11/09 Myrtleford E. coli 3 orgs/100mL Roberts Rd A seasonal Boil Water Notice was in place as of 1/11/09. E. coli was detected as part of an additional monitoring program . Resample was clear.
14/12/09 Myrtleford E. coli 1 org/100mL in two reticulation sites Ultra violet lamps were replaced in November 2009, Boil Water Notice was in place. A media release to remind customers to boil water was prepared for local newspapers and media prior to the holiday season.
18/01/10 Myrtleford E. coli 1 org/100mL Boil Water Notice was in place. The construction works are under way for the new water treatment plant to be completed by end 2010.
1/03/10 Myrtleford Enterococcus detection 1 org/100mL
5/09/10 –17/09/10
Myrtleford Boil Water Notice Due to heavy rainfall and risk of inundation of the non-residual reticulation system, a precautionary BWN was implemented to reduce health risks. Additional monitoring was undertaken. Note: Supply from the new system occurred early Aug 2011.
13/09/10 – ongoing Myrtleford E.coli : 1org/100mL Detected during BWN post flood event
(13/9/10). Unfiltered site with no residual disinfection.
20/09/10 – ongoing Myrtleford E.coli :1org/100mL Increased monitoring of the reticulation allowed additional vigilance and response flushing. In cases of detections WTP (UV system) was checked and localised areas were flushed.
22/09/10- ongoing Myrtleford E.coli : 1org/100mL at 2 locations Increased monitoring of the reticulation allowed additional vigilance and response flushing. In cases of detections WTP (UVsystem) was checked and localised areas were flushed.
24/01/11- ongoing Myrtleford Enterococci : 3orgs/100mL Increased monitoring of the reticulation allowed additional vigilance and response flushing. In cases of detections WTP (UV system) was checked and localised areas were flushed. Note: any of the ‘additional’ microbial detections were reported, however were not included in statistical compliance data.
Seasonal Boil Water Notice was in place from 1.11.10 to 30.04.11. Note: Supply from the new system occurred early Aug 2011..
1/02/11 – ongoing Myrtleford E.coli : 10orgs/100mL and Enterococci :3orgs/100mL
14/02/11 – ongoing Myrtleford E.coli : 2orgs/100mL
30/03/11 – ongoing Myrtleford E.coli : 1org/100mL Enterococci : 2org/100mL
11/04/11 – ongoing Myrtleford Enterococci: 1org/100mL
“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
Myrtleford (Victoria) – Cryptosporidium
2008/9: Four positive cryptosporidium results were detected in the reticulation in Corryong High Level, Corryong Low Level, Myrtleford and Tawonga. Each of these localities is unfiltered and Myrtleford and Tawonga do not have residual disinfection. Investigations into these detections did not reveal the source of the detection. North East Water Annual Drinking Water Quality Report 2008/9
“In recent years, Cryptosporidium has come to be regarded as one of the most important waterborne human pathogens in developed countries. Over 30 outbreaks associated with drinking water have beenreported in North America and Britain, with the largest infecting an estimated 403,000 people (Mackenzieet al. 1994). Recent research has led to improved methods for testing water for the presence of humaninfectious species, although such tests remain technically demanding and relatively expensive.
Cryptosporidium is an obligate parasite with a complex life cycle that involves intracellular development in the gut wall, with sexual and asexual reproduction. Thick-walled oocysts, shed in faeces are responsible for transmission. Concentrations of oocysts as high as 14,000 per litre in raw sewage and 5,800 per litre in surface water have been reported (Madore et al. 1987). Oocysts are robust and can survive for weeks to months in fresh water under cold conditions (King and Monis 2007).
There are a number of species of Cryptosporidium, with C. hominis and C. parvum identified as the main causes of disease (cryptosporidiosis) in humans. C. hominis appears to be confined to human hosts, while the C. parvum strains that infect humans also occur in cattle and sheep. C. parvum infection sare particularly common in young animals, and it has been reported that infected calves can excrete up to 10 billion oocysts in one day. Waterborne outbreaks of cryptosporidiosis have been attributed to inadequate or faulty treatment and contamination by human or livestock (particularly cattle) waste.
C. hominis and C. parvum can be distinguished from one another and from other Cryptosporidium species by a number of genotyping methods. Infectivity tests using cell culture techniques have also been developed. Consumption of contaminated drinking water is only one of several mechanisms by which transmission (faecal-oral) can occur. Recreational waters, including swimming pools, are an important source of cryptosporidiosis and direct contact with a human carrier is also a common route of transmission.Transmission of Cryptosporidium can also occur by contact with infected farm animals, and occasionally through contaminated food.” ADWG 2011
Myrtleford (Victoria) – Turbidity
2014/15: Myrtleford Turbidity 6.6NTU
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.
Myrtleford (Victoria) – Aluminium
2016/17: Myrtleford Aluminium 0.57mg/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.