2015/18 – Conara (Tasmania) – Dichloroacetic Acid, Trichloroacetic Acid, Lead, Iron, Aluminium, Colour, Manganese, Temperature, Turbidity


Conara (Tasmania) – Dichloroacetic Acid, Trichloroacetic Acid

August 12 2015 Conara (Tasmania) – Dichoroacetic Acid 100ug/L

August 12 2015 Conara (Tasmania) – Trichoroacetic Acid 210ug/L

November 18 2015 Conara (Tasmania) – Trichoroacetic Acid 110ug/L

2016/17: Conara (Tasmania) – Dichloroacetic Acid 138 ug/L (max), 77.88 (mean)

2016/17: Conara (Tasmania) – Trichloroacetic Acid 222 ug/L (max), 123.5 (mean) DBPs were detected above the ADWG health limits in December 2016 and June 2017. Due to a lack of filtration barriers, precursors to DBPs such as organic matter are not removed. As the system is on a BWA, chlorine residuals were reduced to try and minimise DBP formation. This work is ongoing.

1/9/17: Conara Trichloroacetic acid exceedance at CNW51W03 of 157 ug/L

12/6/18: Conara Trichloroacetic acid exceedance at CNW51W03 of 130 ug/L

Australian Guideline Level: Dichloroacetic Acid 0.100mg/L, Trichloroacetic Acid 0.100mg/L

“Chloroacetic acids are produced in drinking water as by-products of the reaction between chlorine and naturally occurring humic and fulvic acids. Concentrations reported overseas range up to 0.16mg/L and are typically about half the chloroform concentration. The chloroacetic acids are used commercially as reagents or intermediates in the preparation of a wide variety of chemicals. Monochloroacetic acid can be used as a pre-emergent herbicide, dichloroacetic acid as an ingredient in some pharmaceutical products, and trichloroacetic acid as a herbicide, soil sterilant and antiseptic.” Australian Drinking Water Guidelines – National Health and Medical Research Council

Conara (Tasmania) – Lead

September 2016: Conara (Tasmania) – Lead 0.0173mg/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

Conara – Tasmania – Iron

August 12 2015: Conara (Tasmania) – Iron 390ug/L

November 18 2015: Conara (Tasmania) – Iron 344ug/L

March 9 2016: Conara (Tasmania) – Iron 893ug/L

March 9 2016: Conara (Tasmania) – Iron (Dissolved) 703ug/L

June 14 2016: Conara (Tasmania) – Iron 2220ug/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

Conara (Tasmania) – Aluminium

June 14 2016: Conara (Tasmania) Little Cardigan Reservoir – Aluminium 1.730 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.

Conara (Tasmania) – Colour

August 12 2015: Conara (Tasmania) – Colour Apparent 30 PCU

November 18 2015: Conara (Tasmania) – Colour Apparent 16 PCU

March 9 2016: Conara (Tasmania) – Colour Apparent 36 PCU

June 14 2016: Conara (Tasmania) – Colour Apparent 199 PCU

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…

Conara (Tasmania) – Manganese

March 9 2016: Conara (Tasmania) – Manganese Soluble 0.102mg/L

Manganese: ADWG Guidelines 0.5mg/L. ADWG Aesthetic Guideline 0.1mg/L
Manganese is found in the natural environment. Manganese in drinking water above 0.1mg/L can give water an unpleasant taste and stain plumbling fixtures and laundry.

Conara – Tasmania – Temperature

November 24 2015: Conara (Tasmania) – Temperature 20.5C

December 1 2015: Conara (Tasmania) – Temperature 20.4C

December 8 2015: Conara (Tasmania) – Temperature 21.7C

December 15 2015: Conara (Tasmania) – Temperature 22.1C

December 22 2015: Conara (Tasmania) – Temperature 23.9C

December 29 2015: Conara (Tasmania) – Temperature 22.1C

January 5 2016: Conara (Tasmania) – Temperature 22.7C

January 12 2016: Conara (Tasmania) – Temperature 25.2C

January 19 2016: Conara (Tasmania) – Temperature 25.4C

January 27 2016: Conara (Tasmania) – Temperature 23C

February 2 2016: Conara (Tasmania) – Temperature 21.8C

February 9 2016: Conara (Tasmania) – Temperature 26.3C

February 16 2016: Conara (Tasmania) – Temperature 20.5C

February 23 2016: Conara (Tasmania) – Temperature 23.6C

March 1 2016: Conara (Tasmania) – Temperature 20.3C

March 8 2016: Conara (Tasmania) – Temperature 22.3C

March 15 2016: Conara (Tasmania) – Temperature 20C


“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).

Conara – Tasmania – Turbidity

November 10 2015: Conara (Tasmania) – Turbidity 5.64 NTU

November 17 2015: Conara (Tasmania) – Turbidity 7.18 NTU

December 1 2015: Conara (Tasmania) – Turbidity 7.79 NTU

February 2 2016: Conara (Tasmania) – Turbidity 6.49 NTU

February 9 2016: Conara (Tasmania) – Turbidity 11.4 NTU

February 16 2016: Conara (Tasmania) – Turbidity 6.09 NTU

May 24 2016: Conara (Tasmania) – Turbidity 8.5 NTU

June 7 2016: Conara (Tasmania) – Turbidity 7.52 NTU

June 14 2016: Conara (Tasmania) – Turbidity 13.8 NTU

June 21 2016: Conara (Tasmania) – Turbidity 15.2 NTU

June 28 2016: Conara (Tasmania) – Turbidity 12 NTU

2016/17: Conara (Tasmania) – Turbidity 24.3 NTU (max), 4.18 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.