2014/23 – Ayr/Brandon (Queensland) – PFAS, E.coli, Turbidity, Zinc, Chlorate, Lead

Ayr (Queensland) – PFAS

2018/19: Ayr (Queensland) October 2018/February 2019

1Notifiable Incidents details:

(i) Combined PFHxS/PFOS – Reported 12 October 2018 Ayr Water Tower – 0.084 ug/L

Council Chambers Tap – 0.77 ug/L

Samples taken in the Ayr Water Supply Network on 27 September 2018 resulted in the above detections of combined PFHxS/PFOS.

Investigations found this to be as a result of bores 2 and 5 Nelsons Lagoon.

These two bores as well as Bore 3 Nelsons Lagoon, have since been taken offline permanently.

Follow up samples were taken on 16 October 2018 with the following results:

Ayr Water Tower – 0.070 ug/L

Council Chambers Tap – <0.003 ug/L

Samples were again taken on 26 February 2019 with the following results:

Ayr Water Tower – 0.048 ug/L

Council Chambers Tap – 0.018 ug/L

Status for all PFHxS/PFOS – completed pending close out Due to hazard and safety concerns with access to the Council Chambers Tap, this location has been changed to the Council Chambers Bore 15 Reticulation site which is in close proximity to the previous location but in a safer area.


After receiving a directive from the Department of Health advising drinking water service providers test their drinking water for PFAS as soon as practicable and after an internal risk assessment,

BSC commenced PFAS sampling with the 6 bores at Nelsons Borefield in Ayr.

Results for initial samples taken by Queensland Health on 29 March 2018 showed levels in all bores in Nelsons, South Ayr and Home Hill tested below the draft ADWG guideline limit of 0.07 ug/L total PFOS/PFAxS. Queensland Health decided to resample on 9 May 2018. Test results received on Friday 25th May showed Bores 2 and 5 Nelsons over the draft limits with results as


• Bore 2 – 0.22 ug/L

• Bore 5 – 0.18 ug/L

Bores 2 and 5 Nelsons were immediately turned off and tagged out within an hour of results being received

• The Mayor and Chief Executive Officer were informed in relation to test results and actions

• DNRME, the Water Supply Regulator was informed of the test results by phone at 3pm via the DWQI hotline and in writing by 5pm

• Resampling of all Nelsons zone area plus three reticulation locations South Ayr – Basin Tap, Council Chambers and Ayr Water Tower was performed on 28 May 2018. Bores 1, 3, 4, 5 and 6 plus the three reticulation samples all returned results under the guideline value.

• Follow up sample results for PFOS/PFAxS as follows:

o 28/05/2018 – Nelsons Bore 2 – 0.43 ug/L

o 28/05/2018 – Nelsons Bore 5 – 0.03 ug/L

o Reticulation network samples on 7 June and 12 June 2018 returned results well below the guideline value.

o 14 June 2018 – Bore 2 Nelsons – 0.42 ug/L (standing) and 0.43 ug/L (running)

o 14 June 2018 – Bore 5 Nelsons – 0.029 ug/L (standing) and 0.066 ug/L (running)

Bores 2 and 5 Nelsons remain switched off and no longer in use. Council is investigating the installation of additional bores for the Ayr/Brandon network in areas with no PFAS detection.

Monitoring of PFAS is ongoing in both the BSC’s raw water and reticulation network. These samples will be added to the Verification Monitoring Schedule of the Council’s DWQMP.

Drinking Water Quality Management Plan

Annual Report 2017/18 Burdekin Shire Council

Ayr/Braddon (Queensland): E.coli
2014/15: Ayr/Braddon Park (Queensland) – 1org/100mL
Source: Burdekin Shire Drinking Water Management Plan 2014/15

“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

Ayr/Brandon (Queensland) – Turbidity

2020/21: Ayr/Brandon (Queensland) – Turbidity 7NTU (max), 1.28NTU (average)

2022/23: Ayr/Brandon (Queensland) – Turbidity 6NTU (max), 2.375NTU (average)

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

2020/21: Ayr/Brandon (Qld) – Zinc

2020/21: Ayr/Brandon (Qld) – Zinc 3.9mg/L (max), 0.003mg/L (min), 0.3177mg/L (mean)

Based on aesthetic considerations (taste), the concentration of zinc in drinking water should
be less than 3 mg/L. No health-based guideline value is proposed for zinc.

Zinc is widely distributed and occurs in small amounts in almost all rocks, commonly as the sulfide. It is used as a coating to prevent corrosion of iron and steel products, and in the manufacture of brass. Zinc oxide is an important component in the manufacture of paint and rubber products, including tyres.

In surface and ground waters, the concentration of zinc from natural leaching is usually less than 0.01 mg/L. Tap water can contain much higher concentrations as a result of corrosion of zinc-coated pipes and fittings. Zinc concentrations in galvanised iron rainwater tanks are typically 2 mg/L to 4 mg/L but have been reported as high as 11 mg/L.

Taste problems can occur if the zinc concentration in drinking water exceeds 3 mg/L. Water with a zinc concentration above 5 mg/L tends to be opalescent, develops a greasy film when boiled, and has an undesirable dry ‘metallic’ taste. Zinc is present in plant and animal tissues, and food is the major source of zinc intake. Drinking water usually makes a negligible contribution to total intake. 2011 ADWG

Ayr/Brandon – (Queensland) Chlorate

2020/21: Ayr/Brandon (Qld) Chlorate 1.05 mg/L (max), 0.276 mg/L (average/mean)

Chlorite: ADWG Health 0.3mg/L.

Chlorite and chlorate are disinfection by-products of chlorine dioxide disinfection process.

“… industry are having serious problems meeting chlorite/chlorate limits that were proposed in the new Australian Drinking Water Guidelines, especially for disinfection in long distance pipelines that are dosed with sodium hyptochlorite” pers comm 18/5/11.

“Chlorite occurs in drinking water when chlorine dioxide is used for purification purposes. The
International Agency for Research on Cancer (IARC) has concluded that chlorite is not classifiable as carcinogenic to humans and is listed in the Group 3 category. Changes in red blood vessels due to oxidative stress are a major concern with excessive levels of Chlorite in drinking water. According to the US EPA, potential health problems for people drinking Chorite above safe drinking water guideline include: Anemia in infants and young children and nervous system effects.” https://water.epa.gov/drink/contaminants/index.cfm

“Chlorine dioxide (chlorite) is rarely used as a disinfectant in Australian reticulated supplies.
When used, the chlorite residual is generally maintained between 0.2mg/L and 0.4mg/L. It is
particularly effective inthe control of manganese-reducing bacteria. Few data are available on
chlorate levels in Australian water supplies….Chlorine dioxide, chlorite, and chlorate are all
absorbed rapidly by the gastrointestinal tract into blood plasma and distributed to the major
organs. All compounds appear to be rapidly metabolised. Chlorine dioxide has been shown to
impair neurobehavioural and neurological development in rats exposed before birth. Experimental studies with rats and monkeys exposed to chlorine dioxide in drinking water have shown some evidence of thyroid toxicity; however, because of the studies’ limitations, it is difficult to draw firm conclusions (WHO 2005) The primary concern with chlorite and chlorate is oxidative stress resulting in changes in red blood cells. This end point is seen in laboratory animals and, by analogy with chlorate, in humans exposed to high doses in poisoning incidents (WHO 2005).” Australian Drinking Water Guidelines – National Health and Medical Research Centre

“…Subchronic studies in animals (cats, mice, rats and monkeys) indicate that chlorite and chlorate cause haematological changes (osmotic fragility, oxidative stress, increase in mean corpuscular volume), stomach lesions and increased spleen and adrenal weights… Neurobehavioural effects (lowered auditory startle amplitude, decreased brain weight and decreased exploratory activity) are the most sensitive endpoints following oral exposure to chlorite…” https://www.hc-sc.gc.ca/ewh-semt/pubs/water-eau/chlorite-chlorate/indexeng.
php#sec10_1Guidelines for Canadian Drinking Water Quality.

2022/23 Ayr/Brandon (Queensland) – Lead

2022/23: Ayr/Brandon (Queensland) Lead – Total 0.018mg/L (max), 0.008 (mean)

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