2015/18: Georgetown (Queensland) – Chlorate

2017/18: Georgetown (Queensland) – Chlorate 1.81mg/L (max), 0.653mg/L (av.)

“… ongoing incident for detection of Chlorate – a parameter with no water quality criteria taken from the Georgetown Rec Grounds. 0.367, 0.442, 1.70, 1.52 & 0.456 Mg/L was/were detected…We are testing for chlorate quarterly and monitoring the situation. We turn over our chlorine as frequent as possible and keep it out of the sun”

Etheridge Shire Annual Drinking Water Quality Management Plan 2015/16

2015/16: Incident Description: Chlorate – Georgetown DWI-7-49-00014. We have an ongoing incident for detection of Chlorate – a parameter with no water quality criteria. We regularly detect chlorates in our treated water. We send updates along with detection levels to The Drinking Water regulators and Health Department monthly.

Etheridge Shire Annual Drinking Water Quality Management Plan 2017/18

2021/22: Georgetown There were two ongoing incidents at Georgetown for the detection of Bromide & Chlorate, which are parameters with no water quality criteria although we have now adopted guidelines. An investigation Report was submitted on the 5-4-2021 and a guideline value of 1 mg/L was agreed upon for Bromide and this ongoing incident was closed.
An investigation Report was submitted on the 3-8-2021 and a guideline value of .8 mg/L was agreed upon for Chlorates and this ongoing incident was closed.
This financial year there was one new instance at Georgetown where the Regulator was notified
under sections 102 or 102A of the Act. This was a 1.18 mg/L detection of Chlorate on the 21-2-2022 which has an adopted guideline of .8 mg/L.

Etheridge Shire Annual Drinking Water Quality Management Plan 2021/22

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.

2015/16: Georgetown (Queensland) – Bromide

We have an ongoing incident for detection of Bromide – a parameter with no water quality criteria taken from the Georgetown Rec Grounds. 0.008, & 0.013 Mg/L was/were detected.

Etheridge Shire Annual Drinking Water Quality Management Plan 2015/16

Incident Description: Bromide – Georgetown 0.017mg/L of Bromide which has no ADWG Health value was detected on the 15-11-2017 at the Georgetown rec Grounds and incident DWI-7-49-00023 was opened. Since then we have had 5 low detections within 12 monthly samples. We send updates along with detection levels to The Drinking Water regulators and Health Department monthly.

Etheridge Shire Annual Drinking Water Quality Management Plan 2017/18

2018/19: Georgetown (Queensland) – Bromate

Incident Description: Bromate – Georgetown 0.072mg/L of Bromate which has a ADWG Health limit of 0.02mg/L was detected on the 11-7-2018 at the Georgetown Rec Grounds L and incident DWI-7-49-00024 was opened. Since then we have had 0 detections over the health limit within 4 tests done monthly. We seem to have occasional detections.