23/11/09: E.coli Corryong High level E. coli detection at Playles Hill tank 2orgs/100mL.
15/02/10 E. coli detection at Playles Hill tank 9orgs/100mL
Due to a reduction in water usage and extended storage times in the Playles Hill tank, chlorine residual levels decreased. The chlorine dose was increased and water was flushed through the reticulation system to increase the chlorine residual levels. Resamples were clear.
20/01/10 Corryong High Level Enterococcus detection at Greenham St Basin 1org/100mL Following high coliform counts from the initial sample, further tests were done to test for Enterococci. Chlorine residual levels were 1.5mg/L
21/05/10 Corryong High Level, Corryong Low Level and Cudgewa Boil Water Notice (BWN) instated 21/05/10 to 9/08/10. Due to increased sediment and presence of algae, the raw water turbidity was elevated which could compromise the UV and chlorine disinfection at an unfiltered site. Short term action: communication of BWN to towns, media, critical customers. Medium term action was an alternate water supply to reduce the total turbidity Longer term action is a treatment plant upgrade due for completion by 2013.
21/03/11 <24hr Corryong HL (Greenham st basin) E.coli : 2 orgs/100mL Chlorine residual was increased and resample was clear.
24 April 2012 (<24hours) Corryong Low Level E. coli detection(1 orgs/100 mL) An E. coli detection occurred due to decreased water usage and a subsequently low chlorine residual. Investigation was unable to determine the source of contamination. Chlorine dosing was increased, monitoring and flushing was conducted. Subsequent microbiological results were clear. Operation of high level reticulation was reviewed and refined.
“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
Corryong (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
Corryong (Victoria) Lead
2010/11: Corryong (low level) Lead 0.01mg/L
Lead Australian Drinking Water Guideline 0.01mg/L
“… Lead can be present in drinking water as a result of dissolution from natural sources, or from household plumbing systems containing lead. These may include lead in pipes, or in solder used to seal joints. The amount of lead dissolved will depend on a number of factors including pH, water hardness and the standing time of the water.
Lead is the most common of the heavy metals and is mined widely throughout the world. It is used in the production of lead acid batteries, solder, alloys, cable sheathing, paint pigments, rust inhibitors, ammunition, glazes and plastic stabilisers. The organo-lead compounds tetramethyl and tetraethyl lead are used extensively as anti-knock and lubricating compounds in gasoline…ADWG 2011
Corryong – Victoria – Turbidity (maximum levels)
2007/8: Corryong (High Level) (Victoria) – Turbidity 13 NTU
2007/8: Corryong (Low Level) (Victoria) – Turbidity 18 NTU
2008/9: Corryong (High Level) (Victoria) – Turbidity 13 NTU
2008/9: Corryong (Low Level) (Victoria) – Turbidity 18 NTU
2009/10: Corryong (high level) Turbidity 8.6NTU
2009/10: Corryong (low level) Turbidity 7.4NTU
2010/11: Corryong (high level) Turbidity 19NTU
2010/11: Corryong (low level) Turbidity 7NTU
2011/12: Corryong (high level) Turbidity 7.7NTU
2011/12: Corryong (low level) Turbidity 14NTU
2012/13: Corryong (high level) Turbidity 20NTU
2012/13: Corryong (low level) Turbidity 12NTU
2013/14: Corryong (low level) Turbidity 6.4NTU
2014/15: Corryong (high level) Turbidity 5.1NTU
2015/16 Corryong (low level) Turbidity 6.9NTU
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
Corryong – Victoria – Iron
2007/08: Corryong (Low Level) (Victoria) – Iron 0.37mg/L
2008/09: Corryong (High Level) (Victoria) – Iron 0.54mg/L
2008/09: Corryong (Low Level) (Victoria) – Iron 0.32mg/L
2011/12: Corryong (high level) Iron 0.37mg/L
2011/12: Corryong (low level) Iron 0.4mg/L
2012/13: Corryong (high level) Iron 0.58mg/L
2012/13: Corryong (low level) Iron 0.83mg/L
2013/14: Corryong (high level) Iron 0.52mg/L
2013/14: Corryong (low level) Iron 1.5mg/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
Corryong (Victoria) – Aluminium
2016/17 Corryong (low level) Aluminium 2.1mg/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.
Mercury: Australian Drinking Water Guideline 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.