2004/10 + 2012/21: Cobden (Victoria) – Microcystis sp, Chloral Hydrate, Aluminium, Colour, Taste & Odour

Cobden (Victoria) – Microcystis

23 January–13 February 2013. Cobden raw water storage. Microcystis sp.– 5900 cells/mL

Cobden (Victoria) – Chloral Hydrate

Highest Detections only  2009/10

Cobden 20ug/L [mean 10ug/L] Chloral Hydrate 2009/10

2004 Australian Drinking Water Guideline: Trichloroacetaldehyde (chloral hydrate): 0.02mg/L

2011 Australian Drinking Water Guideline: Trichloroacetaldehyde (chloral hydrate): 0.1mg/L

“Chloral hydrate is a disinfection by-product, arising from chlorination of water containing naturally occurring organic material (NOM). Chloral hydrate has only been detected by Goulburn Valley Water since changing to a new contract testing laboratory in November 2007. The Department of Health is currently conducting a study into the detection of chloral hydrate across Victoria.”

Cobden (Victoria) – Aluminium

September 2004: Cobden (Victoria) Aluminium 1.8mg/L (Highest Level Only)
2005/6: Cobden (Victoria) Aluminium 1.1mg/L (Highest Level Only)
2006/7: Cobden (Victoria) Aluminium 1.2mg/L (Highest Level Only)
2007/8: Cobden (Victoria) Aluminium 0.42mg/L (Highest Level Only)
2008/9: Cobden (Victoria) Aluminium 0.65mg/L (Highest Level Only)
2013/14: Cobden (Victoria) Aluminium 0.3mg/L (Highest Level Only)
2014/15: Cobden (Victoria) Aluminium 0.26mg/L (Highest Level Only)

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.

Cobden – (Victoria) – Colour

2013/14: Cobden (Victoria) – Colour Apparent 19 Pt-Co (Highest Level Only)

Based on aesthetic considerations, true colour in drinking water should not exceed 15 HU.

“… Colour is generally related to organic content, and while colour derived from natural sources such as humic and fulvic acids is not a health consideration, chlorination of such water can produce a variety of chlorinated organic compounds as by-products (see Section 6.3.2 on disinfection by-products). If the colour is high at the time of disinfection, then the water should be checked for disinfection by-products. It should be noted, however, that low colour at the time of disinfection does not necessarily mean that the concentration of disinfection by-products will be low…

Cobden (Victoria) – Taste and Odour

25/1/21-28/1/21: Seasonal algae growth event in the raw water basin produced customer  complaints of earthy tasting water. Bypassing the raw water storage and feeding raw
water directly from the Otway pipeline to the treatment plant. Extensive flushing of the township to turn over volumes of water from the affected area. Wannon Water external web site updated with notice of possible taste and odour issues, their causes and relevant information.Targeted social media notice/information to customers in the Cobden area.
Commercial customers notified of taste and odour issues.