2017/23 – Greenvale (Queensland) – Aluminium, Cadmium, Turbidity, Colour, Iron, Chlorine, Chlorate

Greenvale Water Supply (January 2023-March 2023) Non Potable

2 March 2023 (Charters Towers Regional Council)

The extraction of water from the Burdekin River, and the treatment and water reticulation network provided to the Greenvale community is operating as it has since it was transferred to Council in the early 2000s.

Since then, Council has been managing the system and complying with water quality standards.

More recently, Council has entered into discussions with the ASMTI (Australian Singapore Military Training Initiative) to provide new drinking water and wastewater treatment systems for the community.

Prior to Christmas 2022, there was a process failure at the Greenvale Water Treatment Plant that caused excess chlorination and increased chlorate levels in the water supply.

This was a reportable incident and Council advised the regulator, Queensland Health that it had occurred.

The water supply was in normal operation a few days after the incident, however due to a change in Queensland Health Water Quality Standards, Queensland Health have since directed Council to notify the community that the water supply is ‘Non-Potable’; that is, not fit for human consumption.

National Australian Drinking Water Guidelines (ADWG) have a higher threshold rate for chlorates, and the Greenvale water supply is within those standards, however Queensland Health has determined a more cautious approach and has lower acceptable thresholds.

Council is currently providing bottled drinking water to the community and will continue to do so until there is a viable alternative potable water supply.

While the water is deemed non-potable, it can still be used for other household purposes such as washing and for use for pets and plants, but cannot be consumed, that is, not to be used to drink or to use for cooking purposes.

The timeframe to implement a robust and appropriate solution will take approximately 12 months, with an estimated cost in the region of $3 – $4 million, to be undertaken in 2 stages:

  • Stage 1 will involve a modified chlorination system which can be installed within 6 months.
  • Stage 2 will involve further works addressing all issues and provide a water source classified as potable, which will take up to another 6 months.

Council has completed concept designs and is now undertaking a detailed design and construction program in conjunction with the ASMTI project.

Council acknowledges that the current arrangements represent a significant impact to the community and ask for patience whilst the delivery of an improved water supply is sourced and installed.

Due to the scale and technical issues of the project, Council is not able to address the water supply issues in the short-term but is committed to providing a robust long-term solution for the community.

30 Jan 2023

The Mayor, Deputy Mayor, and Councillors visited Greenvale with the CEO and Council Officers on Friday, 27 January 2023 to update and inform the community about the current situation with the drinking water supply and Council’s action plan to address the problem.

While the water supply is declared Non-Potable, Council will continue to provide alternative supply via bottled water.  In response to requests from the community, some drinking water will also be provided in containers with taps rather than screw top bottles.

Council has engaged a consultant to assess the situation, consider alternative methods to improve water quality, and provide estimates of costs and timeframes.  A draft report has been submitted and is under review.

It is expected that resumption of normal supply by using alternative disinfection systems may take up to six months.  The establishment and commissioning of a treatment plant that will remove the turbidity and other contaminants from the water will take longer.  This is intended to be completed as a preliminary activity in advance of the Australia-Singapore Military Training Initiative (ASMTI), and Council will seek reimbursement to cover the costs of the works.

Council is focused on minimising the disruption to normal activities in Greenvale, and appreciates the patience of the community during this challenging period.

2017/19 – Greenvale (Queensland) – Aluminium

2017/18: Greenvale (Queensland) – Aluminium 5.11mg/L (max), 0.64mg/L (av)

2018/19: Greenvale (Queensland) – Aluminium 2.9mg/L (max), 0.413mg/L (av)

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.

2017/18 – Greenvale – Cadmium

2017/18: Greenvale (Queensland) – Cadmium 0.006mg/L (max), 0.0008mg/L (av.)

ADWG Cadmium Guideline. 0.002mg/L

The primary route of exposure of cadmium is via contaminated water or food. Fertiliser can be a source of excessive cadmium as can rainwater tanks. It has been linked to cancer, lung disorders, kidney disease and autoimmune disease.

Greenvale (Queensland) – Turbidity

2017/18: Greenvale (Queensland) – Turbidity. 63.4 NTU (max), 8.8NTU (mean)

2018/19: Greenvale (Queensland) – Turbidity. 71.2 NTU (max), 10.7NTU (mean)

2019/20: Greenvale (Queensland) – Turbidity. 19.3 NTU (max), 2.2NTU (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.

Greenvale (Queensland) – Colour

2017/18: Greenvale (Queensland) – Colour. 22 Pt-Co Units (max), 5.2 Pt-Co Units (mean)

“At times colour is above the ADWG guideline criteria….Generally the colour of treated water at GISC is below the ADWG value, however, large spikes were observed in January 2013 due to an increase in the concentration of manganese in the source water.”

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…

Greenvale (Queensland) – Iron

2017/18: Greenvale (Queensland) – Iron 2.9mg/L (max), 0.5mg/L (mean)

2018/19: Greenvale (Queensland) – Iron 2.6mg/L (max), 0.38mg/L (mean)

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

Greenvale (Queensland) – Chlorine

2017/18: Greenvale (Qld) – Chlorine (free) 4.92mg/L (max), 2.5mg/L (av.)

2018/19: Greenvale (Qld) – Chlorine (free) 4.97mg/L (max), 2.14mg/L (av.)

Chlorine dissociates in water to form free chlorine, which consists of aqueous molecular chlorine, hypochlorous acid and hypochlorite ion. Chlorine and hypochlorites are toxic to microorganisms and are used extensively as disinfectants for drinking water supplies. Chlorine is also used to disinfect sewage and wastewater, swimming pool water, in-plant supplies, and industrial cooling water.

Chlorine has an odour threshold in drinking water of about 0.6 mg/L, but some people are particularly sensitive and can detect amounts as low as 0.2 mg/L. Water authorities may need to exceed the odour threshold value of 0.6 mg/L in order to maintain an effective disinfectant residual.

In the food industry, chlorine and hypochlorites are used for general sanitation and for odour control. Large amounts of chlorine are used in the production of industrial and domestic disinfectants and bleaches, and it is used in the synthesis of a large range of chemical compounds.

Free chlorine reacts with ammonia and certain nitrogen compounds to form combined chlorine. With ammonia, chlorine forms chloramines (monochloramine, dichloramine and nitrogen trichloride or trichloramine) (APHA 2012). Chloramines are used for disinfection but are weaker oxidising agents than free chlorine.

Free chlorine and combined chlorine may be present simultaneously (APHA 2012). The term totalchlorine refers to the sum of free chlorine and combined chlorine present in a sample.

Chlorine (Free) ADWG Guideline: 5mg/L (Chlorine in chloraminated supplies 4.1mg/L). Chlorine dissociates in water to form free chlorine, which consists of aqueous molecular chlorine, hypochlorous acid and hypochlorite ion.

Chlorine (Total) ADWG Guideline 5mg/L (chloraminated supplies 4.1mg/L): The term total chlorine refers to the sum of free chlorine and combined chlorine present in a sample