2003/6 + 2009/16: Merino (Victoria) – Arsenic, Hardness, Turbidity, Aluminium

Merino (Victoria) – Arsenic

Reported highest reading Nov 2003: Merino 0.50mg/L – 0.75mg/L

Highest Victorian reading 2005-10: Merino 0.13mg/L

“Merino was previously sourced from the Mocamboro bore supply. Water form this aquifer contains naturally high levels of Arsenic. To reduce the level of Arsenic, a new pipeline was constructed to supply Merino from the Casterton Water Treatment Plant.” Wannon Water Annual Drinking Water Report 2005/6

Arsenic problems have also been recorded at Merino and Darlington. “MERINO residents will no
longer have to worry about arsenic problems in their water supply after gaining a new one worth nearly $1 million. A pipeline from the Casterton water supply was brought online in Merino on December 1, 2005… In November 2003, it was reported that Merino’s arsenic level was between 50 and 75 micrograms per litre. The allowable limit at the time was 50 MPL. However, new drinking water guidelines from July 1 2004 saw the allowable limit drop sharply to just seven MPL – putting the town’s water supply well above the legal level. Then Glenelg Water chief executive, Kevin Safe, said there were long-term effects with arsenic in the water supply – but it had to be consumed at a level of 300 MPL for between five and 25 years..” https://www.spec.com.au/blog/2005/12/13/nomore-

Arsenic: Australian Drinking Water Guideline = 0.01mg/L

Arsenic is bioaccumulative and symptoms may take 10-15 years to develop after expsoure at high levels. Drinking water can be contaminated with inorganic arsenic through wind blown dust, leaching or runoff from soil, rocks and sediment. Groundwater sources such as bores will usually have higher arsenic levels than surface water. In major Australian reticulated water supplies concentrations of arsenic range up to 0.015mg/L, with typical values less than
0.005mg/L. https://www.health.qld.gov.au/ph/documents/ehu/2676.pdf

Merino – Victoria – Hardness

2012/13: Merino (Victoria) – Calcium Hardness 230mg/L (Highest Detection Only)

2013/14: Merino (Victoria) – Calcium Hardness 240mg/L (Highest Detection Only)

2014/15: Merino (Victoria) – Calcium Hardness 250mg/L (Highest Detection Only)

2015/16: Merino (Victoria) – Calcium Hardness 260mg/L (Highest Detection Only)


“To minimise undesirable build‑up of scale in hot water systems, total hardness (as calcium
carbonate) in drinking water should not exceed 200 mg/L.

Hard water requires more soap than soft water to obtain a lather. It can also cause scale to form on hot water pipes and fittings. Hardness is caused primarily by the presence of calcium and magnesium ions, although other cations such as strontium, iron, manganese and barium can also contribute.”

Australian Drinking Water Guidelines 2011

Merino – Victoria – Turbidity

2013/14: Merino (Victoria) – Turbidity 11 NTU (Maximum detection during year)

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.

Merino (Victoria) – Aluminium

2009/10: Merino (Victoria) Aluminium 0.23mg/L (Natural Sources)
Australian Guideline: Aluminium 0.2mg/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.