2003/17: Newcastle Waters (Northern Territory) – E.coli, Hardness, Iodine

Newcastle Waters (Northern Territory) – E.coli

9/5/11: Newcastle Waters 1 positive sample 3MPN/100mL

2010/11: E. coli 1 positive detection. 95.7% compliance over year

Newcastle Waters 1 e.coli detection 3 February 2014 4MPN/100mL

“The Gunn Point incident was likely due to low level faecal contamination from small animals, while inadequate chlorination due to a chlorination system disruption is likely to have contributed to identification of E.coli in samples from the Garawa and Newcastle Waters
water supplies.” Power and Water Corporation Water Quality Report 2016
Newcastle Waters 3 February 2014: Samples with E.coli detections (1). Number of E.coli detected in sample (MPN/10ml) (4)

“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

Newcastle Waters – Northern Territory – Hardness

2003/04: Newcastle Waters Hardness 360mg/L

2004/05: Newcastle Waters Hardness 334mg/L

2005/06: Newcastle Waters Hardness 334mg/L

2007/08: Newcastle Waters Hardness 318mg/L

2008/09: Newcastle Waters Hardness 320mg/L

2009/10: Newcastle Waters Hardness 281mg/L

2010/11: Newcastle Waters Hardness 293mg/L

2011/12: Newcastle Waters  Hardness 303mg/L

2012/13: Newcastle Waters Hardness 300mg/L

2013/14: Newcastle Waters Hardness 320mg/L

2014/15: Newcastle Waters Hardness 315mg/L

2015/16: Newcastle Waters Hardness 334mg/L

2016/17: Newcastle Waters Hardness 346mg/L


“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

Newcastle Waters – (Northern Territory) – Iodine

2007/08: Newcastle Waters Iodine 0.11mg/L

Iodide: Based on health considerations, the concentration of iodide in drinking water should
not exceed 0.5 mg/L.
Iodine: No guideline value has been set for molecular iodine.
The element iodine is present naturally in seawater, nitrate minerals and seaweed, mostly in the form of iodide salts. It may be present in water due to leaching from salt and mineral deposits. Iodide can be oxidised to molecular iodine with strong disinfectants such as chlorine.
Molecular iodine solutions are used as antiseptics and as sanitising agents in hospitals and laboratories.
Iodine is occasionally used for the emergency disinfection of water for field use but is not used for disinfecting larger drinking water supplies. Iodide is used in pharmaceutical and photographic materials. Iodine has a taste threshold in water of about 0.15 mg/L.
Iodide occurs in cows’ milk and seafood. Some countries add iodide to table salt to compensate for iodide-deficient diets.